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Home My WebLink About20194021.tiffAPPENDIX B UNIT 1 SURFACE WATER CALCULATIONS APPENDIX B -'I cflarlieCaSalson nannaleaCt====znialfliartritaragialheilitil.9klate.kanagipaltarenvarprramormsoc MectZAWMUlaisailediaa _ UPDATED DESIGN AND OPERATIONS PLAN NORTH WELD SANITARY LANDFILL AULT, COLORADO Prepared By: Rust Environment & Infrastructure, Inc. 5575 LTC Parkway, Suite 200 Englewood, Colorado 80111 January 1996 sie 9' t 0 to. 6 t b V Revised y Waste Management Disposal im: f; Collorefido, Inc.. November; 1927 NORTH WELD SANITARY LANDFILL UPDATED DESIGN AND OPERATIONS PLAN FIGURES 1 - t Prr• p'• - • . r•;, fir - C`i-- '•+`- .t.. •• • • - C r • • 't t . • S • - C 3 1 + .1 • .\ — rill As, '-{ ' Ns.- ... =2- i ( . .......:‘ '41 • 'I.'S. •-•••-ile7"1.:"1.4"-::::11•4•.1.7•-• ' . "%is .. % ">. t.4. ..:;419i ‘.:\ .... \ ."Y.\ t ▪ '•-'w--r••- J -N.�_ ..,.+. I-. 'v"L. N. -••••••••N \ . .�\'aS •�(__'�t lL •`•.,L' - •y ' I. gariseasseiwer .ht4 .. 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( C HAN 146 L, La chin e pas 4 NORTH WELD SANITARY LANDFILL UPDATED DESIGN AND OPERATIONS PLAN APPENDIX B LANDFILL PERIMETER CHANNELS DESIGN Rust Environment as Infrastructure CALCULATION SHEET PAGE OF 41 PROJECT O. i224921,/fro TENT --- L dt.. (cep; SUBJECT t - Prepared By ens. Date 12e15 PROJECT ! , .'"'. ,, .r ----- . � Reviewed By /41e1pOs Date tt, A l Approved By Date Parente te ; esiek:fitmeit-e eskitela peel aortal 3'4 A peak t i s .1 'fie at 100 t t t ) +2 ' - kalif/ norm e vies + t Croon1Hoot. I capoesost ii 1 +a +"kc et". r m tutee .. ID" d 4444 Wort FDA' AD $,sJMeI,friv fiek &hoot t +a- saI s fegtoltc v ori ikeer y Ofinhoshilirr a +0 3 son► 4 -rat Ame4 tot. pa INA ; Hots s 1a r .' f t s #- tiirc. son!1 ,pt. rs } lleta (4 FebtivicLAr art keit lock woo, ewireikala Sea - .t -r ,` ► 411:"Pri 1'1► raer ► tte '- 4 kre ''$ k Cb t tt ' g. i i thrwai rir 1 i Vt k, Gi ; �r' . 4446a.* Alt 1 +' e. + j MCP 41$ + + ' i rs i fitz bests 4frievtvor.... is f. cerficomean at -4•1 a in 40L,A0L- Pieta) • - 07 C 4 +.)# rz..#0` rsto w V; o 4ti How 11A%,c,.1 &DAIS flow assatinelpt s4 a on First data Vei *to' 'o ft $ vs c drS. a r' ; - leo Imo. C. l,9 ter‘ acrilfti Row 4 -In c.. c.. rte. f'*o asks► on t 1Qgusted o s sec. vuh. fie (A.) tatiorta. Ira tires ire rarikA fat eisi'orievit,tot+rci, sea is 5 t;red. ass m' j 1 ' .. c,, Ceps/+V t. pea 1 1..� d i reel 'Ss'arid. ra 0ot/stir Co vivtiAri eta : cadAr 52) % cosier X11 t TA acct* A O5 s o s 'M kat. 4- , oii) i O• ( 3 r scoot r kdavive I ciao rat O. 0 3•C ricktiaj risa, t` p .- rap a + DO ' r+r %se r+C. i Precc Oltrinserv1/4.. 1100 a ?rake hie%) re az in I to "' rat& 'Pi home"" Z. re) 11 rev 1 1 r94 sca'e: 4 sq inch cr,5 is i Rust Environment & infrastructure CALCULATION SHEET • PAGE OF ,ieitr PRO;.; ECT NO 12 4,5- I _ CL ENS 4J en 40rft,_ SUBJECT Per i% #- c-_....-- --- Pfeoared By 64145 Date _12_ `, sore COL on Ceirt n Kier I Reviewed By M 4 Date Ase'7"_ Approved By _....-... Date it; gr i reasol*r-s ^ea ths t artioc.ineci F Ore. nee* e.. ;tit° ° ItiA miel mein +5 ,t-, ;,,,. /oleo c n he fer��., ,.,, , t& ("HA litikLT 43 t- h e_, $ 1.4 lea CIPt 441 c. COI 9 4.444 usAtitdisterkil, res Q Isar s is tit -ca. -pis cs AFB SeC Cas all 0 C avid, F 4200 00O TSB glsre> II too Coro .3020 Fie I 7-10 1 1 co c 64(0 Sty t', dale lt Sao i,olo 4LO ArtirecktteA. . 0 12 to 12.x! LZ 60 catO og Dl 10 ,0 .24 %Lc,I & & *to aio Ole' O oas 0,02 O30o4 0 004, 0103 0ztI 646001 00(, 00,04 • OLI O .04 C CI, en CIP r off+'' of 008 0.0`2 - £1° 3 c4 c cas Coct cr 9-5 UDC+ ci445 1 33 C. ,5 orr ars 233 c9 -j cs es• ko-INA see \ „rare 40 etei ea sm. 44.4.4., cLAN\-ttcAt1/4.44h L v.) IseCitess ketr+S b L 15 lat,e,r ,,,ifr1/4 S i to 1 1. r42-461.67; to v"sh's' Cr g— 41n, g.. -14s list fine tot le r Se e -e. \ 5 . 413, scale: 4 sq./inch • .. r 1 Rust Environment & Infrastructure Denver Division - Solid Waste Design Surface Water Run -Of - Open Channel Sizing FILE NAME: Cpench an.wk3 DISK NAME: North Weld USES CHANNEL DIMENSIONS AND SLOPE TO CALCULATE V AND Q FROM MANNING'S EQUATION FOR OPEN -CHANNEL FLOW: Project: North Weld Sanitary Landfill By: ES CHANNEL NAME Channel A -> B SIDESLOPEI z 1.0 Channel Channel E -> F Channel F ->O Channel G -> H Channel Ft -> I Channel I -> J Channel 2 -> 3 Channel 6 -> 7 1.0 Channel 7 -> 8 Channel 9 -> 10 Channel 10 -> 11 Channel 11 -> 12 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 SIDESLOPE 2 z 1.0 1.0 1.0 1,0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.486 213 1/2 �_-- r s n Prof. No.: 82488.100 Date: 02 -Oct -95 Checked Sy: MRH WIDTH (b) (1 12.0 12.0 12.0 12.0 12,0 2.0 .0 2.0 2.0 2.0 2.0 DEPTH (d) (ft) 1.000 2.400 2.500 1.800 1.600 2.100 1.400 0.028 0.025 0.004 0.004 0.009 0.006 0.006 0.006 0.045 0.026 Rust Environment & Infrastructure Denver Division - Solid Waste Design Surface Water Run -Off - Open Channel Sizing FILE NAME: Openchan.wk3 DISK NAME: North Weld USES CHANNEL DIMENSIONS AND SLOPE TO CALCULATE V AND 0 FROM MANNING'S EQUATION FOR OPEN -CHANNEL FLOW: Project: North Weld Sanitary Landfill By: EGS 1.486 213 1/2 n Prole No.: 82488.100 Date 02 -Oct -95 Checked By: MRH MANNINGS AREA (A) F DRL.C RAD. VELOCITY I jV)(fps) IMAX. O1( FLOW ) REG. FLOW (cis) CHANNEL NO. 01 (sq ft (rMft) NAME - Channel A -a B 0.035 13.000 0.877 2.75 35.8 35.0 36.1 35.0 0.035 7.560 0.552 4.78 Channel B -> C Channel C -> D 0.035 8.890 0.588 4.71 41.9 35.0 Channel 0 -> E 0.035 14.410 0.954 4.87 ' 70.1 69.0 Channel E -> F 0.040 20.250 1.247 5.09 103,1 100,0 Channel F ->G 0.035 34.580 1.839 4.03 13943 133,0 Channel C -> H 0.035 40.553 2.051 4,33 175.8 175.0 Channel H -> I - 0.040 25_410 1.520 6.95 183,4 175.0 Channel I -> J 0,040 36.250 1.901 5,50 235.6 233.0 J Channel 1 -> 2 4.78_ 27.6 24.0 0.035 5.760 0.883 Channel 2 -> 3 0.035 6.840 0.965 3.93 26.9 24.0 0.035 7.410 1.005 3.30 24.4 24.0 Channel 3 -> 5 Channel 5 -> 6 0.035 8.610 1.084 3.47 29.9 28.0 Channel 6 -> 7 0.040 5,760 0.883 4.95 28.5 28.0 Channel 7 -> 8 0.035 8.610 1.084 3.47 29.9 28.0 Channel 8 -> 9 H 0.040 4.760 0.799 6,78_ 32.3 _ 32.0 Channel 9 -> 10 0.040 8.840 0.965 5.85 40.0 36.0 Channel 10 -> 11 0.035 9.240 1.124 4.10 37.9 36.0 Channel 11 -> 12 0.035 10.560 1.202 4.29 45..3___ 44.0 North Weld Sanitary Landfill Perimeter Channel Schedule Channel Designation Landfill Terraces Channel A -> B Channel B -> C Channel C -> D Channel O -> E Channel E -> F Channel F -> Channel G -> H Channel H -> I Channel I -> J Channel 1 -> 2 Channel 2 -> 3 Channel 3 -> 5 Channel 5 -> 6 Channel 6 -> 7 Channel 7 -> 3 Channel 8 -> 9 Channel 9 -> 10 Channel 18 -> 11 Channel 11-> 12 Slope (1V 0.040 8.005 0.028 0.025 0.014 0.014 0.004 0.004 0.020 0,013 0.015 0.009 0.006 0.006 0.021 0.006 0.045 0.026 0.008 04 008 Flow Rate (cis) 66.0 3.0 35.0 35.0 89.0 100.0 133.0 175.0 175.0 233.0 24.0 24,0 28.0 28.0 28.0 32.0 38,0 36.0 44,0 Velocity (ftis) 6.16 2.75 4.78 4.71 4.87 5.09 4.03 4.33 6.95 6.50 4.78 3.93 3.30 3.47 4,95 3.47 6.78 5.85 4.10 4.29 Bottom Width b. (ft} 12 12 12 12 12 12 12 }12 12 24.0 2 2 Water Depth de (ft) 1.3 1.0 0.6 0.7 1.1 1.4 2.4 2,8 1.8 2.3 1.6 1.8 1.9 2.1 1.6 2.1 1.4 1.6 2.2 2.4 Channel Depth De (ft) 1.5 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3+0 3,0 3+0 3,0 3;0 3.0 3.0 3;0 3.{ 3.0 3.0 Channel Lining Grass (Rip Rap Ends) Grass Grass Grass Grass Grass Grass Grass Rip Rap Rip Rap Grass Grass Grass Grass Rip Rap Grass Rip Rap Rip Rap Grass Grass NORTH WELD SANITARY LANDFILL UPDATED DESIGN AND OPERATIONS PLAN APPENDIX C SEDIMENTATION POND OUTLET DESIGN Rust Environment i infrastructure Z e COI :c es Motrig &deco setP . _._ ilia WW1 a...a ._--••• •••••••IM• CALCULATiON SHEET sJeJ,_cr _DEurr tens eiF -o Vent y 014 at • . • .F ' • w .;• 4 d • sor .7- goo ,?,;2•'i • 00 m4 s- ° 6MAE' M..• _(,• _ _ _p'_ _ _ : r o z. e t c rR M eks-''i"' sit r a + P 3 ' A t T*e Jo T' H co tr. ° S Am i Tout '' 1�farhJ b ;ate i$ 2tEN D es litittePro aro lacer an L0 ca f''tr h.i tOO Pte c. 5 Q P 4 Aar sat'Jr Sarnia D as to. At e- Des Leib pia c ht.(' i } r� +- t. W Idid Coop\- ' k a r' ' s Dap -- +per ' ; 'Note s it Cr; krater taw 'I' ; t, 13 , toil 3 All Skive re" t thee.r Cats; ‘ ; itritss % l' t. atwes ;et Kew. +a ateAwici ris +"kt ' -c ne usha., irer- ra • crrOM °Kit Snt4. GLeAttet 0 pea N.S-cfr k6 Ps of.. IOC depia.r irciriok treisceaSe irmkdoer.,. i-c ri. , .r r to cose e.•,r- 4:::t/tar a ,.,vet. yvr--i 4h43 a► -Act rct +les Pit o tee . 4..,1 4 .,t. ► tokatieVH. rowte. e Se 5e tear S+br {; : o trkeiss •. c lP ' gel- p esti t ' ;ter r. . let 14eic"StCOLS S or 9rtatasc iAln4 ryeS + + .se 44141. ‘a eel/cot-Ai •9-ro Ns% nuts gocrere v rk ea\ c ft OctseIS Ca FY% p kat 4-ed„, Pr rA Pro creessok Ore, 4rii+"'` Pita I ‘o iv\ co Irciatacte ) so; I Cuo -c-frikar go,.) 14-0; -0 i ... .. ttca.,.nrot. ' oil G ra +l ? D 8a.*eotas +-kat. Moat-it:Yeti4- .-+ - e. t4 lroyson fro test t k -+ 4 serk O p : ,,, 5; 4-.e. ...• p fa sx, i ark t `r a <set_ fiAtteka finoac-t; iolmaakeks • scare: 4 sq rich Rust Environment & Infrastructure CALCULATION SHEET SUBJECT STE MIAJ4-r1 Wop rr Sere,v14tris * . ASkrok Wrt SDP - ! E + '2 •r nut... -t '►Ir 4-v t11 r a ,r'ti r M map •.y 1.►X' '� _r ''1 • 0 ,• -� :,•' - • �• 4 1 4 WIM i see ctql Leo yL i 1�ti•M-rr s1 J ion 'c- 5ed it lista ht. fri c et ponot -, prey ro As i 40 ist1P pi -„ 14-A2 i",s Jim 'mot cx, 3 eat emp gherfritervir.T , .flak, citrocsaale '-t-ea. a ;- Li o 7' otr b , i. " -f.k, r `0 ft 1 +.• n.is S • 7' l 1/4; r +r,s paesit. ... Iaum.) ote heA INA rink. cot 4,O kocf. aerts 0 ;Om-. of How co Oa b•e. Cst fetaditer44 from :resitrg, frotkic At 0 ek at • Pea- igiq3/4 O4.C CietJGOJ'i*.OS•le- 'Ss I) fes 'Peva Aro irlit wesSes? Peak O4o:se-kiwi st. crows. Q r: e tok. ss .0 r;en e , a k 0 u `- Siam kc L'cr s. leo east.. 1 4 40 'Ur 6, h i ; Peo-14% ;kik% F =a a., 3 3 • 0 as p., t h 4 10 + • o cei-s Pea aegeterio 0. z siD 9-4.- "ThrtD z iv / , g Ctrdfr n Awe otej I ` -t& Item ta.." sr + . s. ar")1 '~, `a. ofroo( c tc it 1,`c' letAsioLices o'er. ski -me" - - Letieelet scale: 4 se inch Quick TR-55 Version: 5.46 /N: 1315430243 Page 1 TR-55 TABULAR HYDROCRAPH METHOD Type II Distribution (24 hr. Duration Storm) Executed: 10-02-1995 12:36:06 Watershed file: --> NORTH5YR. SD Hydrograph file: --> NORTH .HYD North Weld Sanitary Landfill 5 -Year, 24 -Hour Storm Event Run-off By: Mike Feinstein October 2, 1995 ››» Input Parameters Used to Compute Hydrograph <ccc Subarea Description AREA (acres) CN Tc (hrs) * Tt (hrs) Pre o ip . (in) Runoff Ia/p (in) input/used subarea subarea subarea subarea subarea subarea subarea g f e d C b a Travel 6.80 5.50 11.00 8.60 17.50 18.30 54600 80.0 80.0 80.0 80.0 60.0 80.0 80.0 0.20 0.10 0.20 0.10 0.10 0.20 0.40 0.20 0.20 0.10 0.00 0,00 0.00 0.00 2.20 2.20 2.20 2.20 2120 2.20 2.20 0.69 0.69 0.69 0.69 0.69 0.69 0.69 . 23 . 23 . 23 . 23 . 3 . 23 . 23 . 30 . 30 .30 . 30 . 30 . 30 . 30 time from subarea outfall to composite watershed outfall point. Total area = 121.70 acres or 0.1902 sq.mi Peak discharge = 59 cfs WARNING: Drainage areas of two or more subareas differ by a factor of 5 or greater. Computer Modifications of Input Parameters <<ccc Subarea Description Input Values Tc * Tt (hr) (hr) Rounded Values Ia/p Tc * Tt Interpolated (hr) (hr) (Yes/No) Ia/p Messages subarea ;ubarea subarea subarea subarea subarea subarea g f e d c b a 0.20 0.10 0.20 0.10 0.10 020 0.40 0.20 0420 0,10 0a00 0.00 0.00 0.00 No No No No No No No * Travel time e from subarea outfall to composite watershed ershed outfall point, * Tc & Tt are available in the hydrograph tables. Quick TR-55 Version: 5.46 S/N: 1315430243 Page 2 TR-55 5 TABULAR HYDROGRAPH METHOD Type II Distribution (24 hr. Duration Storm) Watershed file: Hydrograph file: Executed: 10-02-1995 12:36:06 --> NORTH5YR . WSD - - NORTH 2= North Weld Sanitary Landfill 5 -Year, 24 -Hour Storm Event Run-off By: Mike Heinstein October 2, 1995 >>>> Subarea Summary of Subarea Times to Peak ‹‹c‹ subarea subarea subarea subarea subarea subarea subarea g f 0 d C b a Composite Watershed Peak Discharge at Composite Outfall (cfs) 4 4 7 9 18 14 29 Time to Peak at Composite Outfall (hrs) 12.3 12*3 12.3 12,1 1261 12,2 12.4 59 12.3 Quick TR-55 Version: 5.46 N: 1315430243 Page 3 TR-55 5 5 TABULAR HYDRO .PH METHOD Type II Distribution ( 4 hr. Duration Storm) Executed: 10-02-1995 12:36:06 Watershed file: --> NORTH5 R. WSD Hydrograph file: - _ > NORTH . MYD North Weld Sanitary Landfill 5 -Year, 24 -Hour Storm Event Run-off By: Mike �F a ins 'M.. e i n October 2; 1995 Composite Hydrograph Summary (cfs) Subarea Description 11.0 11.3 11.6 11.9 1240 12.1 12.2 12.3 1244 hr hr hr hr hr hr hr hr hr ;u}barea g 0 0 0 0 0 1 2 4 4 subarea f 0 0 0 0 0 0 2 4 4 subarea e 0 0 0 0 0 2 5 7 6 atharea d 0 0 0 1 5 9 5 2 2 subarea, c 0 0 0 3 11 18 10 4 3 nubare a b 0 0 0 1 4 11 14 10 5 learea a 0 0 0 0 2 7 17 28 29 Total (cfs) 0 0 0 5 22 48 55 59 53 Subarea Description 12.5 12.6 12.7 12.8 13.0 13.2 13.4 13.6 13.6 hr hr hr hr hr hr hr hr hr Subarea. g 3 2 2 1 1 1 1 1 0 ;ubare a, f 3 2 1 1 1 1 0 0 0 subarea e 4 3 2 2 1 1 1 1 1 subarea d 1 1 1 1 1 1 1 1 1 subarea c 3 2 2 2 2 1 1 1 1 .subarea b 4 3 3 2 2 2 1 1 1 subarea a 24 18 14 11 7 6 5 4 4 Cotal (cfs) 42 31 25 20 15 13 10 9 8 Quick TR-55 Version: 5.46 SiN: 1315430243 TR-55 5 5 TABULAR HYDRO PH METHOD Type II Distribution ( 4 hr. Duration Storm) Executed: 10-02-1995 12:36:06 Watershed file: --> NORTH5Y . SD Hydrograph file: -- - > NORTH . HYD North Weld. Sanitary Landfill 5 -Year, 24 -Hour Storm Event Run-off By: Mike He iriste in October 2, 1995 Composite Hydrograph Summary (cfs) Page 4 Subarea Description 1400 hr 14.3 14.6 hr hr 15.0 15.5 hr hr 16.0 16.5 hr hr 17.0 17.5 hr hr subarea g subarea f subarea e subarea d subarea c Subarea b subarea a 0 0 1 0 1 1 4 0 0 1 0 1 1 3 0 0 1 0 1 1 3 0 0 1 0 1 1 3 0 0 0 0 1 I 2 0 0 0 0 1 1 2 0 0 0 0 1 1 2 0 0 0 0 1 1 2 0 0 0 0 1 1 2 .sotal (cfs) 7 6 6 6 4 4 4 4 4 Subarea Description 18.0 hr 190 20.0 hr hr 22.0 26,0 hr hr subarea subarea f subarea e subarea d subarea c ;ubarea b iubarea a 0 0 0 0 1 1 2 0 0 0 0 0 0 1 0 0 0 0 0 0 1 0 0 0 0 0 0 1 0 0 0 0 0 0 0 Total (cfs) 4 1 1 1 0 Quick TR-55 Version: 5.46 B/N: 13154 3 0243 Page 5 TR-55 TABULAR HYDROGRAPH METHOD Type II Distribution ( 4 hr. Duration Storm) Executed: 10-02-1995 12:35:05 Watershed file: --> NORTH5 YR . WSD Hydrograph raph file: - - > NORTH .HAD North Weld Sanitary Landfill 5 -Year, 24 -Hour Storm Event Run-off By: Mike Heinstein October 2/ 1995 Time (hrs) Flow (cfs) 11.0 11.1 11.2 11.3 11.4 11.5 11.6 11.7 11.8 11.9 12.0 12.1 12.2 12.3 12.4 12.5 12.6 12.7 12.8 12.9 13.0 13.1. 13.2 13.3 13.4 13.5 13.6 13.7 13.8 13.9 1460 14.1 14.2 14.3 14.4 14.5 14.6 0 0 0 0 0 0 0 2 3 5 22 48 55 59 53 42 31 25 20 18 15 14 13 12 10 10 9 8 8 8 7 7 6 5 6 6 6 Time (hrs) 14.8 14.9 15.0 15.1 15.2 15.3 15.4 15.5 15.6 15.7 15.8 15.9 16.0 16.1 16.2 16.3 16.4 16.5 16,6 16.7 16.8 16.9 17.0 17.1 17.2 17.3 17.4 17.5 17.6 17.7 17.8 17.9 18.0 18.1 18.2 18.3 18.4 Flow (cfs) 6 6 6 6 5 5 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 3 3 3 14.7 18.5 2 Quick TR-55 Version: 5.46 S/N: 1315430243 Page 6 TR-55 5 5 TABULAR HYDROGRAPH RAPH METHOD Type II Distribution ( 4 hr. Duration Storm) Executed: 10-02-1995 12:36:06 Watershed file: - - > NORTH5YR . W D Hydrograph graph file: --> NORTH .HYD D North Weld Sanitary Landfill 5 -Year, 24 -Hour Storm Event Run-off By: Mike Heinstein October 2, 1995 Time (hrs) Flow (cfs) 18.6 18.7 18.8 18.9 19.0 19.1 19.2 19.3 19.4 19.5 19.6 19.7 19.8 19.9 20.0 20.1 20.2 20.3 20.4 20,5 20.6 20.7 20.8 20.9 21.0 21.1 21.2 21.3 2144 21.5 21.6 21.7 21.8 21.9 22.0 22.1 22.2 22.3 2 2 2 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1. I I 1 1 1 1 1 1 1 1 1 Time (hrs) Flow (cfs) 22.4 22,5 22.6 22.7 22.8 22.9 23.0 23.1 23,2 23.3 23.4 23.5 23.6 23.7 23.8 23.9 24.0 24.1 24.2 24.3 224.5 4 . 4 24.6 24.7 24.8 24.9 25.0 25.1 25,2 25.3 25.4 25.5 25.6 25,7 25.8 25,9 1 1 1 1 1 1 1 1 1 I 1 1 1 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 APPENDIX B-2 Golder Associates Inc. 44 Union Boulevards Suite 3W Lakewood, CO USA 80228 Telephone (303) 9804)540 Fax (303) 985-2080 October 14, 2002 Mr. Doug J enberr'ry Colorado Department of Public Health and Environment FIMW MD-SWI -82 4300 Cherry Creek Drive South Denver, Colorado 80246.1530 Ms. Cindi Etcheverry Weld County, Department of Public Health and Environment 1555 N. 17th Avenue Greeley, Colorado 80631 Our Ref.: 023-2387 RE: NORTH WELD SANITARY LANDFILL (NWSL), RETENTION POND CONSTRUCTION QUALITY ASSURANCE Dear Mr. Ikenberry and Ms. Etcheverry: On behalf of Waste Management Disposal Services, Inc. (WMDS), Golder Associates Inc. (Golder) is providing this letter to outline a Construction Quality Assurance (CQA) Plan for modification of the existing detention pond at NWSL and request approval of the CQA Plan and the design modification. As previously discussed with ADS, the current pond design includes a stormwater outlet structure. Because of the concern by the Colorado Department of Transportation (CDOT) regarding discharge of stormwater onto the State Right of Way, CDPHE had requested NWSL consider converting the stormwater detention pond to a retention pond. Accordingly, WMDS is proposing the detention pond at NWSL be modified to a retention pond in accordance with the enclosed modified design calculations provided by Earth Tech, Inc. on February 19, 2002. These calculations provide the required dimensions for a retention pond that will store the 100 -year, 24 -hour storm event from the 119 acre completed landfill. The results of this analysis are being incorporated into construction drawings by WMDS. These construction drawings will provide survey points that establish the slope and bottom elevations of the retention pond. Golder will review survey data provided by a licensed surveyor during construction and certify that it is within design tolerances established by the specifications. Upon certification of the survey data, Golder will provide a certification letter sealed by a Professional Engineer in Colorado along with as -built drawings and survey tables that demonstrate that retention pond has been built in accordance with the design. Since NWSL would like to incorporate this work in with the Phase 2 Module I constriction project an expeditious review of this design modification and CQA Plan is appreciated. Colorado Department of Public Health and Environment Doug Ikenberry Weld County, Department of Public Health and Environment Cindi Etchever 7 7 w2 - October 14, 2002 023-2387 If you have any questions feel free to contact the undersigned at 303-980-0540. Sincerely, ti OLDS SSOFIA, INC. f Mark M Clain, P.E. Senior rojcct Manager Attachment: Design Calculations cc: Kin Ogle, WCDPS w/attachment Alan Scheere, WMDS wiattachment Bill Hedberg, WMDS &attachment MEM/ljd t'\O C2\OtO 232387.01OQ 05252.00c Golder Associates • ATTACHMENT HMENT - .:. „ -. . - . - . • - •• :_;-: October 2002 is wrolow 2323$7.OI iia.05 zsg Doc Golder Associates 023-2387. 5575 DTC PArk way, Suite 200, Englewood, Colorado 80111-343;6 February 19, 2002 Mr. Alan Scheere Waste Management of Colorado at CSI 2090 E. 104th Avenue, Suite 300 Denver, Colorado 80233 Re: Re -Evaluation of North Weld Sanitary Landfill Retention Pond and Ground Water Discharge Permit Requirement Dear Mr. Scheere: Earth Tech, Inc. has completed a re-evaluation of the North Weld Sanitary Landfill' s (NWSL) proposed retention pond to store the runoff resulting from a 100 -year, 24 - hour storm event from the fully developed landfill. The re-evaluation of the pond to contain the 100 -year, 24 -hour storm runoff is required due the Colorado Department of Transportation' s concern regarding NWSL's discharge of collected storm water to the Colorado State HIghway 14 right-of-way south of the site. The calculations completed to evaluate the pond are attached. The loo -year, 24 -hour storm event volume is approximately 22.6 acre-feet Using a 1.5 factor of safety((approximately 34 acre-feet) for available storage, the pond's dimensions, as previously designed, can remain at a length of approximately 600 feet and a width of 400 feet with 4KIV side lopes. The depth should be increased by 1.5 feet to 8 feet (elevation 5066.0 feet) in order to limit the top of water elevation to approximately 5073.5 feet, This depth assumes that sediment storage of 2 feet (elevation 5066,0 to 5068,0) is incorporated into the pond's design. Earth Tech contacted the Colorado Department of Public Health and Environment Water Quality Control Department to determine if the surface water storage pond would require a ground water discharge permit. Mr, Liuzzi of the Water Quality Control Department indicated that under the Colorado Discharge Permit System Regulations [SCR 1002-61, f 4 l)(b)(iii), attached], any storm water retention or detention impoundment is exempt from the ground water discharge permit requirement. If you have any questions concerning this re -sizing of the NWSL retention pond, please contact me at (505) 350-1306 or Randy Thompson at (303) 694--6660. Very truly yours, Earth Tech, Inc. Michael R. Heinstein, F.E. Civil Engineer cc: Randy Thompson, }I.E. r \44645‘rawsi\portii-analysis.doc EARTHSTECH Telephone 303-694-6660 Facsimile 303.694.4410 Attica INTERNATIONAL LTD. COMPANY ATTACIIMENT1 CALCULATIONS "'- NWSL RETENTION POND RE-EVALUATION CALCULATION SHEET PROJECT: Waste Management — North Weld Sanitary Landfill — Weld County, Colorado ado CALCULATION TITLE: North Weld Sanita Landfill Retention Revaluation PROJECT NUMBER: 39973.0702 PREPARED BY: MRH PROBLEM STATEMENT REVIEWED/CHECKED BY: DATE: December 16, 2001 PA EgOF a The purpose of this evaluation is to determine the size of the North Weld Sanitary Landfill NW retention pond to store the runoff from a 100 -year, 24 -hour (NWSL) storm event from the fully developed 119 -acre site. DESIGN CRITERIA The flow into the NWSL retention pond was determined during the completion of the January 1995 i h will be used to estimate to Development Plans. The storm hydrograph the total volume of water that must be stored by the pond. SITE LOCATION AND LAYOUT Noah €�Id Say f ��fill NWSL is located approximately six miles west of Colorado State Highway 85 on Colorado State Highway 14. The facility's address is 40000 Weld County Road 25, Ault, Colorado 80610, Final grades for the NWSL were designed to promote positive drainage of precipitation runoff (Site Development Plans [January 1996]). Runoff from the landfill dull slopes will collect in channels and will be conveyed to the proposed retention pond that will be located in the southeast corner of the site. The proposed retention pond was initially designed with 2H:IV sideslopes but, to facilitate easier access to collected sediments, the sideslopes will be flattened to 4 : 1pond was V. The retentionsized to control the runoff volume as a result of a 100 -year, 24 -hour storm event from the 119 acre completed landfill. ANALYSIS RESULTS AND DISCUSSION NWSL Retention Pond_ Capacitv,a5nalysis .............. 1. Design factors developed during the completion of the January 1996 Site Development Mans which were used in this analysis include: p h ch a. 100 -year, 24 -hour storm event flow into the pond from the landfill 214 cis; b. Inlet channel invert elevation to pond ; approximately 5070.0 feet; c. Inlet channel top of water surface elevation due to 100 -year storm = 5072.3 feet; and d. Inlet channel top of sideslope elevation = 5074.0. e. Factor of safety = 1,5 (10O -year, 24 -hour runoff volume) [to account for existing water that may be in the pond at the time of the storm event, etc. CALCULATION SHEET PROJECT: Waste Management— North Weld Sanitary Landfill — Weld County, Colorado CALCULATION TITLE: North Weld Sanitary Landfill Retention Revaluation PROJECT NUMBER: PREPARED BY: REVIEWED/CHECKED BY: 39973.0702 MRH Sediment Stara Working Stormwater Volume aramonemom— _ DATE: December 16, 2001 NWSL Retention Pond Volume Capacity Estimate Elevation Area - (acres) 5068.0 8007.0 5068.0 Toyof Pond Notes: - 5068.0 5060.0 5070.0 5071,0 6072.0 5073.0 5074.0 Cumulative Volume of Storage cre-fl) 0 5A1 5.41 5.53 10.82 ._.--....__..... 5.53 0 0.0 5.70 5.7'0 1.0 5.87 11.74 2.0 6.01 18.03 3.0 6.14 24.56 4.0 628 31.40 S. 6.4 38.52 1 6.0 Depth of Water 0 0 0 1_ Storage volumes and primary structure outflow rates based on a 595 ft x 400 ft retention pond with 4H:1 V sideslopes and located as shown on the January 1996 Site Development Plans. 2. Using the pond volume capacity estimates, the 100 -year, 24 -hour storm hydrograph, developed during the January 1996 completion of the Site Development Plans, can be easily stored in the pond. Pond dimensions: 600 feet in length, 400 feet in width and a total of 8 feet in depth. WOW _ PONDe2 Version: 5.17 S/N: 1295130221 EXECUTED: O7 10e2OOO 11:10:12 Page 1 **, ***** -************ **** *************, ********************* ******* * North Weld Sanitary Landfill * Revised Retention Pond Characteristics Widened Pond to 600x400 * Mike Eeinsteln July 10,2000 * * ***** *** * ** * **** ******* * ** ******* * * ** *** * * **-********** **** *** ** * ** *** * Inflow Hydrograph: NWELDHYD.HYD Rating Table file: NPD D . PND rah -INI AL CONDITIONS ---- Elevation = 5069.80 ft Outflow = 0.00 cfs Storage = 0.00 ac -ft GIVEN EN POND DATA I ELEVATION I (ft) I 15069.80 5070,00 5071.00 1 5072.00 J 5073.00 1 5074.00 I. OUTFLOW I STORAGE 1 (cfs) I (ace ft) I 0.0 0.5 3.5 6.7 10.2 13.0 0.0001 1.1701 7.1101 1361901 19.4001 11. 25.7501 } Met •- Faint ,1.fi4 _ blen S r .4"telt e t SIN eflo INTERMEDIATE ROUTING COMPUTATIONS 23/t (cfs) 0.0 283.1 1720.6 3192.0 4694.8 6231.5 Time increment (t) = 0.100 hrs. • ,• .+ e ► wr .,o, a r an a Imatect,i PS1dr-L C 2S1't + 0 {cfs} 0.0 283.6 1724.1 3198.1 4705.0 6244.5 etc trona a4t 445 61 ,2 ;la 4,1;44% s ;Tweet. kb siirtaven arc,. POND -2 Version: 5.17 S/N: 1295130221 EXECUTED: 07-10-2000 11:10:12 Pond File: Inflow Hydrograph: Out flow Hydrograph: INFLOW HYDROGRAPH I TIME I (hrs ) 11.000 11.100 11.300 11.200 Ja. 1 . 3 0 0 11.400 11.500 11.600 11.700 11.800 11.900 12.000 12.100 1f�� 12 . 2Y Y 12.300 12.400 12.500 12.600 12.700 12.800 12.900 13.000 13.100 13.200 13.300 13.400 13.500 13.600 13.700 13,800 13.900 14.000 14.100 14.200 14.300 14.400 14.500 14.600 14.700 14.600 14.900 15,000 15.100 15.200 15.300 15.400 INFLOW (cfs) 1 I 7.001 8.001 9.001 10.001 12.001 14.001 16. 001 30.001 44.00) 58.001 112.001 192.001 214,001 197.001 172.001 128.001 89.001 66.001 50.001 42.001 35.001 31.001 27.001 24.001 22.001 21.001 20.001 19.001 18.001 18.001 17.001 16.0{0 1 16.00 15.001 15.001 14.001 14.001 { 14.001 4 _ oo l 13.001 13.001 13.001 12.001 12.001 11.001 NWPOND . PND UWELDEYD . HY D @WFLO . YD I I I I I I 1 11+12 (cfs) 15.0 17.0 19.0 22.0 26.0 30.0 46.0 74.0 102.0 170.0 304.0 406.0 411.0 369.0 /300.0 2 1 7.0 155_0 116.0 92.0 77.0 66.0 58.0 51.0 46.0 43.0 41.0 39.0 37.0 36.0 35.0 33.0 32.0 31.0 30.0 29.0 28.0 28.0 28.0 27.0 26.0 26.0 25.0 24.0 23.0 0,1 kr% 1. ROUTING COMPUTATIONS 2S/t -- O (cfs) 0.0 14.9 31.8 50.7 72.4 98.1 127.6 173.0 246.1 346.8 5149 815.6 1216.7 1621.1 1982.0 2272.6 2479.2 2623.3 2727.9 2808.1 2'813.1 2926.8 2972.3 3010.7 3043.9 3074.0 3102.0 3127.8 3151.6 3174.2 3195.8 3215-2 3233.6 3250.9 3267.1 / 3282.3 3296.3 3310.4 3324.3 3337.2 3349.0 3360.8 3371.5 3381.2 3389.9 2511 + 0 1 OUTFLOW (cfs) I (cfs) 0.01 15.01 31.91 50.61, 72.71 98.41 128.11 173.61 247.01 348.11 516.81 818.91 1221.61 1627.71 1990.11 2282.01 2489.61 2634.2 2739.3 2819.9 2885.1 2939.1 2964.8 3023.3 3056.7 3086.9 3115.0 3141.0 3164.8 3187.6 3209.2 3228.8 3247.2 3264.6 3280.9 3296.1 3310.3 3324.3 3338.4 3351.3 3363.2 3375.0 3385.8 3395.5 3404.2 0.00 0.03 0.06 0.13 0.17 0.23 0.31 0.44 0.63 0.99 1.61 2.45 3.30 4.08 4.71 5.16 5.48 5.70 5.88 6.02 6.14 6.24 6.32 6.39 6.46 6.52 6.57 6.63 6.68 6.72 6.77 6,81 6.85 6.89 6.93 6.96 6.99 7.02 7.05 7.08 7.11 7.13 7.16 7.18 Page 2 1 ELEVATION (ft) I 1 5069.80 5069.81 5069.82 '.r•;5069.84 5069.85 5069.87 I 5069.89 1 5069.92 5069.97 5070.04 5070.16 5070.37 5070,65 5070.93 5071.18 5071.38 5071.52 5071.62 5071.69 5€ 71-74 5071.79 5071.82 5071.85 5071.88 5071.90 5071.92 5071.94 I 5071.96 5071.98 5071.99 5072.01 1 5072.02 5072.03 1 5072.04 5072.05 5072.06 1 5072.07 5072.08 5072.09 1 507210 5072.11 50.2,12 5072.12 15072.13 ! 5072.14 •*i a. ► 4.3 -1S-.5 oc' c tQ coca 3 4 w c4 3,140 c+ 4i4130c 6. Cott et p 1.510. E 3a cS3 VII. 3Set c4 3o,tactcc- 5q fig 0 a- GI. cc - 000 cac- aCti *L O 11-ilos cc ItC 51,0 c5 s 3j 140 c4 in° CS 10 44.0 C*' line c4 24 LSO ci 140 to a- il d 2-0 C $- Col WO roc' it* 44 GiSootcr- ; le o 14-6Q Cc' 5100 re. ry T cac. 46 M- t c1 p e'4 tom, cc - 4, tpxo cot ,iioc flb c M1 ito lima di. F. POND -2 Version: 5.17 S/N: 1295130221 EXECUTED: O7-1O-2OOO 11:10:12 Pond File: NWPOND .PND Inflow Rydrograph: NWELDfYD. HYD Outflow }Iydrograph ; NWFLOW .HYD INFLOW YDROGRAPH ROUTING TIME (hrs) 195OO 15.600 15.300 15.8DO 15.900 16.000 16.100 16.200 16.300 16. 4OO 16.500 16.600 16.700 16.800 16.900 17.000 17.100 17.200 17,300 17,400 17.500 17.600 17,700 17.800 17. 9OO 18.000 18.100 18.200 18.300 18.400 18.500 18.600 � 18,1j00 18.800 18.900 19.000 19.100 19.200 19.300 19.400 19.500 19.600 19.700 19.800 19.900 20.000 INFLOW I (cfs) I 11.001 11.001 10.001 10.001 9.001 9.001 9.001 9.001 8.001 8.001 8.001 8.001 8.001 8.001 8.001 8.OOj 8.001 8.001 7.001 7.001 7.001 7.001 7.001 6.001 6.001 6.001 6.001 6.001 6.001 6.001 6.001 6.001 6.001 6.001 6.001 6.001 6.001 6.001 5.001 5.001 5.001 5.001 5.001 4.001 4.001 4.001 I 11+12 1 (cfs) 22.0 22.0 21.0 20.0 19.0 18.0 18.0 18.0 17.0 16.0 16.0 16.0 16.0 16.0 16.0 16.0 16.0 16.0 15.0 14.0 14.0 14.0 / 14 .0 13.0 12.0 12.0 12.0 12.0 12,0 12.0 12.0 12.0 12.0 12.0 12.0 12.0 12.0 12.0 11.0 10.0 10.0 10.0 10.0 9.0 8.0 8.0 1 2S/t ` O 1 (cfs) 3397.5 3405,1 3411.6 3417.1 3421.6 3425.1 3428.6 3432.0 3434.4 3435.9 3437.3 3438.7 3440,1 34415 3442.9 3444.3 3445.7 3447.1 3447.5 3446.8 3446.2 3445.6 3445.0 3443.4 3440.8 3438.2 3435.6 3433.1 3430.5 j 342�J 8.0 3425.5 3423.0 3420.5 3418.0 3415.5 3413.1 3410.6 3408.2 3404.7 3400.3 3395.9 3391.6 3387.2 3381.9 3375.6 3369.4 I 1 1 COMPUTATIONS 2S.lt + O (cfs) 3411.9 3419,5 3426.1. 3431.6 3436.1 3439.6 3443.1 3446.6 3449.0 3450.4 3451,9 3453.3 3454.7 3456.1 3457.5 3458.9 3460.3 3461.7 3462.1 3461.5 3460.8 3460.2 3459.6 3458.0 3455.4 3452.8 3450.2 3447.6 3445.1 3442.5 3440.0 3437.5 3435.0 /'� 3432.5 3430.0 3427.5 3425.1 3422.6 3419.2 3414.7 3410.3 3405.9 3401.6 3396%2 3389.9 3383.6 OUTFLOW (cfs) 7.20 7.21 7.23 7.24 7.25 7.26 7,27 +.28 7.28 7.28 7.29 7.29 ( 7 • . 2 1 7.29 7.30 7.30 7.30 7.31 7.31 7.31 7.31 7.31 7.31 7.31 7.30 7.30 7.29 7.28 7.28 7.27 7.27 7.26 7.25 7.25 7.24 7.24 7.23 7.23 7.22 7.21 7.20 7.19 7.18 7.17 7.16 7.14 7.13 Page 3 IELE TYONI (ft) 5072.14 5072.15 5072.15 5072.15 5072.16 5072416 50.72.16 5072.16 5072.17 5072.17 5072.17 5072.17 5072.17 5072.17 5072.17 5072.17 5072.17 5072.17 5072,17 5072.17 5072.17 5072.17 5072.17 5072.17 5072.17 5072417 5072.17 5072.17 5072.16 5072.16 5072.16 5072.16 5072.16 5072.16 5072415 5072.15 5072.15 5072.15 5072•115 5072.14 577^ �f d2, 14 5072.14 5072.13 5072413 5072,13 5072.12 fl0 cc $ is c 1 110 4 iac-4 :1442.00 I, .,eta cc. c4 1aa cif 30,E a J#o4..aC. j oft 3 bid, '4 ac -c - 3.)m c 3-00 c4 Z13'0 c$ t ' 3 }�J 2.1 rip t+ II 310 .1'540'4 lag o cif 3* C5 Lai i g tl 4 €o cif arlit, if} 1,`+tp c4 14100 Cji I$oo c4- 1% Sad c.4 1.17a6 C9~ tr cox II IN D a- LC sl© Lie 1 I J POND -2 Version: 5.17 S/N: 1295130221 EXECUTED: 07-10-2000 11.10.12 Pond File: NWPOt0 . PND Inflow Hycirograph: NWELDHYD . HYD Outflow Hy ograph : NWFLOW . HYD INFLOW HYDROGRAPH ROOTING COMPUTATIONS TIME (hrs) 20.100 20.200 20.300 20.4Q0 20.500 20.600 20.700 20.800 20.900 21.000 21.100 21.200 2.1300 21.400 21.500 21. 600 21.700 21.800 21.900 22.000 22.100 122.200 2 2 . 3 0 0 22.400 22.500 22.600 22.700 22.800 22.900 23.000 23.100 23,200 23.300 23.400 23.500 23.600 23.700 23.800 23.900 24.000 24.100 24.200 24.300 24.400 24.500 24.600 [ INFLOW I (cfs) 1 4.001 4.001 4*Q01 4.001 4.001 4.001 4..00) 4.001 4.001 4.001 4.001 4.00 4.00 4.00 4.00 4.00 4400 4400 4.00 4.00 4,03 4.00 4.00 4.00 4.00 3.00 3.00 3.00 3.00 3.00 3.00 3.00 3.00 3.00 2.00 2.00 2.00 2.00 2.00 2.00 2.00 2.00 2.00 2.00 2.00 1.00 11+12 (cfs) 8.0 8.0 8.0 8.0 8.0 8.0 8.0 /8 .0 8 ♦ 0 8.0 8.0 8.0 8.0 8.0 8.0 8.0 8.0 8.0 8.0 8.0 8.0 8.0 8.0 8.0 8.0 7.0 6.0 6.0 6.0 6.0 6.0 6.0 6.0 6.0 5.0 4.0 4.0 4.0 4.0 4.0 4.0 4.0 4.0 4.0 4.0 3.0 2S/t - 0 (cfs) 3363.1 3356.9 3350.8 3344.6 3338.5 } 3332.4 3320.3 3314.3 3308.4 3302.4 3296.5 3290.6 3284.7 3278.9 3273.1 3267.3 3261.6 3255.8 3250.1 3244.4 3238.8 { 3233.2 3227.6 3222.0 3215.5 3208.0 3200.5 3193.0 3185.6 3178.3 317049 3163.6 3156.4 �j +� 3148..E 3138.9 } 3129.8 3120.6 3111.6 3102.5 3093.5 3084.6 3075,6 3066.8 3057.9 3048,1 Page 4 2 S/ t + 0 I OUTFLOW I tLEVATI ON (cfs) I lcfs) I (ft) I 3377.41 3371.11 3364.91 3358.81 3352.61 3346.51 3340,41 3334.4 3328.31 3322.3 3316.41 3310.41 3304.5 3298.6 3292.7 3286.9 3281.1 3275.3 3269.6 3263.8 3258.1 32}52'. 4 3246.8 3241.2 3235.6 3229.0 3221.5 3214.0 3206.5 3199.0 3191.6 3184.3 3176.9 3168.6 3161.4 3152.1 3142.9 3133.8 3124.61 3115,61 3106.51 3097.51 3088.6, 30794G I 3070.81 3060.9 7.12 7.10 7.09 7.07 7.06 7.04 7.03 7.02 7.00 6.99 6.97 6.96 6.95 6.33 6.92 6.90 6.89 6.88 6.86 6.85 6.84 6.82 6.81 6.60 6.79 6.77 6.75 6.74 6.72 6.70 6.68 6.67 6.65 6.64 6.62 6.60 6.58 6.56 6.54 6.52 6.50 6.48 6.46 6.44 6.42 6.40 I I I I I I 5072.12 5072.11 5072.11 5072.11 5072.10 5012.10 072.09 5072.09 5072.09 5072.08 5072,08 5072.07 5072.07 5072.07 5072.06 5072,06 5072.05 5072.05 5072.05 5072.04 5072.04 5072.04 5072.03 5072.03 5072.02 5072.02 5072.02 5072.01 5072.01 5072.00 5072.00 5071.99 5071.99 5071.98 5071.97 5071.97 5071.96 5071.96 5071.95 5071.94 5071.94 5071.93 5071.93 5071.92 5071.91 5071.91 %1%No c- &- 1S % tl�+� c.J 44° c5- isMaoc4 11otc c LAS° 4.V t4*to a- �; 080 c4 II ck II no 44- ago tio4 gin 44 ho is 4-Zo c* nta tc FAO a / ere Ito ig-P coce 3-24, .44 S'io POD -2 Version: 5.17 S/N: 1295130221 EXECUTED: 07-10-2000 11:10:12 Pond File: NWWOND .FND Inflow Hydrograph: NWELD YD t HYD Outflow Hydrograph: NWFLOW -HID INFLOW HYDROGRAPH ROUTING COMPUTATIONS 1 TIME airs) 24.700 24.800 24.900 /25.000 25 s 100 25.200 25.300 25.400 25*500 25. 600 25.700 25«800 25. 900 INFLOW 1 (cfs) I 1.00i LOU! 1.001 1.001 1.001 1.001 1.001 0.001 0.001 0.001 0.001 0.001 11+12 (cfs 2.0 2.0 2.0 2.0 2.0 2.0 2.0 1.0 0.0 0.0 0.0 0.0 1 2S/t - 0 (cfs) 3037.4 302647 3016.0 3005.4 2994.8 2984.3 2973.8 2963,4 2952.0 2939,7 2927.4 2915.2 2903.0 2S/ft + 0 1 (cfs) f I 3050.11 3039.41 3028.71 3018.01 3007.41 2996.81 29+86.31 2975.81 2964.41 2952.01 2939.71 2927,41 2915.21 Page 5 OUTFLOW (cfs) 6.38 6.35 6.33 6.31 6.28 6.26 6.24 6.22 6.19 5.15 6.14 6.11 6.08 c �- ELEVATION (ft) 5071.90 5071«89 5071.98 5071.88 5071.87 5071.86 5071.86 5071.85 5071.84 5071.83 5071.82 5071.82 5071.81 rt„ raft. a 514 F I cir 360 4.+ 3 O 4-;- 34azic 34.0 3ito c iitter.c' 1%bar D cc. $4 141O c 1$O c.f X92.1 34TO c f. T -t•.- Id 3i a. . e AITACIMENT COLORADO DEPARTMENT OF PUBLIC HEALTH AND ENVIRONMENT WATER QUALITY CONTROL DEPARTMENT COLORADO DISCHARGE PERMIT SYSTEM REGULATIONS 5CC12 1002-61.14(fl)(BXM) COLORADO DEPARTMENT OF PUBLIC HEALTH AND ENVIRONMENT WATER QUALITY CONTROL COMMISSION REGULATION NO, 61 cOtORADODISCHARGE PERMIT synpvi ADOPTED: EFFECTIVE: AMENDED: EFFECTIVE: AMENDED: EFFECTIVE: AMENDED: EFFECTIVE: AMENDED: EFFECTIVE: AMENDED: EFFECTIVE: AMENDED: EFFECTIVE: AMENDED: EFFECTIVE: AMENDED: EFFECTIVE: AMENDED: EFFECTIVE: AMENDED: EFFECTIVE: AMENDED: EFFECTIVE: AMENDED: EFFECTIVE: EMERGENCY EFFECTIVE: AMENDED: EFFECTIVE: AMENDED: EFFECTIVE: AMENDED: EFFECTIVE: AMENDED: EFFECTIVE: AMENDED: EFFECTIVE: EMERGENCY EFFECTIVE: AMENDED; EFFECTIVE: AMENDED: EFFECTIVE; AMENDED: EFFECTIVE: AMENDED: EFFECTIVE: November 171 1981 December 20,1981 March 291 1982 April 29,1983 September 13, 1983 Dr 31, 1983 May 15, 1984 June 30, 1984 April 14, 1986 May 30, 1986 June 2, 1987 July 31, 1988 May 2, 1988 July 1, 1989 November 2 1988 December 30, 1988 July 10, 1989 August 31 "1989 December 4, 1990 July 1, 1991 January 8,1991 March 21991 June 4,1991 July 1, 1992 November 4, 1991 December 30, 1991 AMENDED: January 6,1992 January -6, 1902 April 7, 1992 July 1, 1993 June 2, 1992 June 30,1992 February 2, 1993 March 30, 1993 August 2,1993 September 30, 1993 July 11, 1934 August 30, 1994 AMENDED: November 14, 1994 November14, 1994 December 12, 1994 January 30,1995 January 9, 1995 March 2; 1995 November 13, 1995 December 30, 1996 May 13, 1996 Juno 38, 1996 I AMENDED: EFFECTIVE: AMENDED: EFFECTIVE: AMENDED: EFFECTIVE: EMERGENCY ENCY AMENDED: EFFECTIVE: AMENDED: EFFECTIVE: AMENDED: EFFECTIVE: AMENDED: EFFECTIVE: July 14, 1997 August 30, 1997 March 10, 998 April 30, 1998 February 9, 1999 March 30, 1999 March 9, 1999 March 30, 1999 March 9, 1999 April 30, 1999 January 8, 2001 March 2, 2001 November 13, 2001 Decorator 30, 2001 TABLE OF CONTENTS Ent 110 Colorado D iscis q1 Q F ermi ,Sypte -�_,_'. inula ion ■,a.ara+#ai4 f!!a• tat• 1 6141 Genet* Pt VisicIn lirra+i/rT.T.• v41T.TMT.t4+IRrrr rar }a. si (1) Scope and Purpose r r aaa►ae■• ! a•rs/ae+: T.Ikf1R+Nlta4+; fa4 1 (2) Incorporation by Reference if4ra}r+f•s+a 4ta�• +t 1*44 .iY ►at+a{.+i* isiira }i ■aaa r/r• I (3)SeveLabilit ►a it f! w}+fiiia} aY•ar r.+.R+}ia /ii pets I 612 Definitions sea i.sraf lrhlra lf.i} t!■t t4iF i+a ages •}iar r+ir!• 1 61.3 Applicablittv 13 (1) Applicability Generally 13 (2) Applicability a Stormate/ i /i.TTaahs*i st4 sat a;a r, ■!1R►tRsr rte+♦ 13 a�ai,aa_ft■,■■slrarhfht i (3) Applicability - Concentrated Aquatic Animal Production Facilities 24 (4) Applicability a Aquaculture Projects cast...l..., a r++ 25 (5) Applicability r Silviculture Activities ■.!!! ar •*I...r*rrTt/►RRR*• r ease. 25 61.4 a lic tior for. a Permit, i*.a1e,■r4at t!*lT.h_.rart t!*Y■yR■■ti■+Mal44T+ia}I...a1.f♦ 25 � . _... ... Generally �y �'`� emu+ (1) Application Requirements- Genetalll /r.r►T•l It itf l+/zrae ■, ITs sr Mi _aYrrar++• alts 25 (2) Application Requirements e Existing •Manufacturing* Com ercial* Mining, and Silvaculture Discharges . R T r,i ,. i. • t .... a 30 (3) Application Requirements ents a Storrnwaterl..i ai.wise.,....f.!►t.aii i.i.44*•. T._R,.. 34 (4) Application Requirements w Manufacturing, ng, of mercial, Mining and BiMMicultur l Facilities which Discharge Only Non -Process Water r{ }/ ■ itr to as re rar. ► r.■a r!!• }a ai a 50 (5) Application Requirements - New and Existing Aquatic Animal Production Facilities ..■■! 51 (6) Application Requirements a New and Existing POTWs a...■.}hr .■.i •.T,t t 52 (7) Application Requirements - New Sources and New Discharges P, ii •f f Y 1+., a a. }i .. i 53 (8) Application Requirements For Housed Commercial Swine Feeding Operations 55 61.5 Review, Determination, otice and �i.i a i 'M+! # 55 (1) Review of an Application ...,t .a h •. }} ii• .i • • r, t.. of R 55 (2) Public Notice and Comment a Draft Permits l,rh•.,ra.S *St+h}..i+ ,..,. 56 (3) Public Meetings on Draft Permits 4 1 •h ar rr .rraa 58 (4) Public Access I to Information if lr.riti :,..Rrl.. ►a fr,{rt a.. i. 59 61.6 Issued Permits #tiiti fa.air }.. !•itttht4+It titan, t•TIR.q►...dirt it TR rsal.R 60 61.7 Pemiit Adrudicatory Hearin€ /il/TTtTT!/fin t■Rf►.tt 60 (1) Administrative Stays a Renewal Permits ...}ttf4t}traa1.; , If 61 61.8 Terms and Conditions of Permits }+r}r, iitr..,.,.162 (1) Prohibitions •.ee•#r.i 7TT►.TTRf1•TT••77••rr jLr•i i.• (2) Definition of Effluent Limitations * f a• • s 63 (3) Conditions of Permits nitV i/ra rlia t!!!*•aTa a.srtt t,.raa;r} rt• 41r•/+a•raa 82 i I PAGE 61.9 (1) (2) 61.10 61.11 61.12 61613 (1) (2) (3) (4) (5) (6) 61.14 (1) (2) (3) (a) (5) (6) (7) (8) (9) (10) 61.15 61 .16 fkAcnitoringt Recording and Reporting i i+►ri+A M44 rit,t r4„t, ra- r■:,ar•yt•a rr sr 8 Notification Requirements • a •a r•rs: as♦rraraa.ta* 89 Transfer of Permits r ++ ► r t 4 t 91 Terms and Conditions Applicable to Domestic Wastewater Works tit*..4a.+.r,+4 91 Permit Modificationr Suspensions Revocation and Reissuance and Termination .. 93 Effect of Permit Issuance r aa a 96 Discharges to Ditches and Other MantMade Conveyance Structures, Conditions for Phase II Municipal Stormwater Permits .. *t4.41r•. t ■ .+..�t.. r. t Qualifying Local Programs s . ....4F.a,r•.r r►a,.,l.4r«.a««4ar►+4:+ 1-•••••111.• 9 ,,....#,.101 Other Types ofPermits 3►ct**rt.r a.aaa ra +.rfr+ a •a •ra ♦ra4i 102 Temporary and Extended Permitstrts4 f„ ■,.a.eas* rs*tr4 r• •rrr.+rra.a►4■,•rrr*ta 102 General Permits •- i,aawrYaa►aa aarraas ti rrr 102 ivi,od cat _nd renewal f_ ermits !Antibacrklrsllcjirm•••ii►►4riMYFft*►itfl►k•ti „ann. a►at•yai►rar,r+ 105 War.Qvalitt8taftdarcis Barspd, Permits ir Determination of Economici_Environmental Public ltlll...j Energy Impact Variances I. 107 105 Ho eJi$SMmtuerciaISwineFeJaQpecflQnMf! wrafarr■■r•a 110 Scope and Purpose :r ai.PV • i aaau a F-■waa.,rraaaa aa.a 1410 Specific Applicability 110 Applications and Required Plans i as _ , ....... r r... 110 Requirements for Housed Commercial Swine Feeding Operations+r e a t ,.i116 Permit Fees „r,r a F .... 126 Enforcement 126 Vrar.u-n i •at r.. 127 a Applicability 127 Regulation by Implementing Agencies s. r+ i/ t+ t r R** t t 4 4 r, 4► I t t i l r s M i a t a i •. i a t. s r r r t l R a a r 125 Impacts from Surface Waters4f■FtrFpa■rtaaf as ■raa 125 Point of Compliance 128 Verification cation Monitoring 129 Control Plan a r 129 Land Disposal .rer•aiaa ■ a a ■wrrtr 129 Land Treatment i 130 Impoundments •.fa., r.. -■.+..a.. 130 Application and Operation Requirements 131 Permit Fees so General Provisions 4apa,_..,.•_r_. -.r.., .aa.t..a. ■. 131 d,l in7station by the Division„F •s• • t-3Mr++i►# tiF., e.i as .• •...is 132 (b) The Division shall take immediate enforcement action against any housed commercial swine feeding operation that has exceeded the agronomic rate limit of subsection 61.13(4)(e). 61.14 GROUND WATER 00) APPLICABILITY (a) Pursuant to this section a permit shall be required for ail land application discharges and for all discharges from impoundments unless: (I) The discharge is exempted under section 61.14(1)(b); (ii) The discharge is subject to regulation by one of the implementing agencies described in 61.14(2); (iii) The impoundment has received a waiver from the Division pursuant to section 61.14(9)(a); or (iv) The owner of a land application system can demonstrate that <A) The design and operation of the system will result in complete evapotranspiration of the effluent; (B) There is adequate storage provided for the effluent during periods of inclement weather or where the ground has been frozen unless the provisions of (A) above, can be met during the entire year; and; (C) Any augmentation plan or substitute supply plan for the land application site does not provide a credit for return of the effluent to ground water. (b) The following facilities are specifically exempted from coverage under the ground water discharge provisions of this regulation: (I) Any impoundment subject to regulation under the Uranium Mill Tailings Radiation Control Act, 42 U.S.C., Section 7901, et seq. as amended. (ii) Any impoundment used in the treatment, storage or recharge of raw or potable water; (iii) Any stormwater retention or detention impoundment. (iv) Any impoundment or land application system for which a currently valid certificate of designation has been obtained pursuant to the Solid Waste Disposal Sites and Facilities Act, C.R.S. 1973, 30-20-1011 et seq. as amended, and other impoundments or land application systems subject to regulation under that Act which are not part of a wastewater treatment system for which a Colorado Discharge Permit System (CDPS) permit for a discharge to surface waters is required. (v) Any tank which does not result in a discharge to ground water. 127 APPENDIX B-3 Golder Assiciates CALCULATIONS Date: 08 -November 2010 Made by: Project No.: 103-81825 Checked by: Subject: Supplemental Runon H&H Calculations Reviewed by: Project NWLF Drainage Improvements Short Title: 1.0 OBJECTIVES MBR Ve3 v Size a culvert to collect and divert stormwater runoff contributing to the maintenance shop area from the western portions of the landfill property to the landfill perimeter channels. Peak 100 -year, 24 -hour stormwater flowrates for the landfill were calculated in a previous calculation (RUST, 1995). This report will determine the 100 -year, 24 -hour peak flow contributing to a point upgradient of the maintenance shop area. This peakflow will then be added directly (no routing) to the flowrates provided in the RUST calculation to determine if the as -designed perimeter channels will be adequate to accommodate the additional runoff. .0 METHODS • The contributing basin was delineated based on site topography, see Figure 1. SCS Curve Number (ON) methodology is used to model the basin to the north of the existing berm and shop area; TR-55 methodology was used to model the basin in HEC-HMS (USAGE, 2009). Parameters including subbasin area, CN, lag time, and slope are entered into HEC-HMS to develop a peak flow. Attachment A presents the manning's n and overland flow coefficients. A routing diagram displaying the routing logic is included in the attached HEC-HMS output (Attachment B). Channel dimensions provided by Waste Management were analyzed using a spreadsheet that solves for normal depth using manning's equation to verify that the additional stormwater flows determined in this calculation would not cause overtopping. Culvert sizing was performed using HY8 culvert sizing software (FHWA, 2009). 3.0 DATA AND ASSUMPTIONS NOAA Technical Atlas 2 precipitation depths (NOAA, 1973): Return Period (years) Precipitation (inches) Depth 2 1.7 --- 100 4.0 [IA The rainfall hyetograph assumed an SCS Type II storm distribution. Minimum lag time is 3 minutes. Ea SCS Curve Number was assumed to be 84 for consistency with the RUST calculations Manning's roughness coefficients: Channel Lining/Material Manning's n for Stability Manning's n for Capacity Grass 0.030 0.033 Riprap 0.035 0.040 HDPE (culvert) 0.012 0.012 JA10JOBS\103-81825 NW'LF Drainage Improvements\Surface water\Runyon H&H Calculaiion_docx Golder Associates Inc. 44 Union Boulevard, Suite 300 Lakewood, CO 80228 USA Tel: (303) 980-0540 Fax: (303) 985-2080 vwww.golder.com Golder Associates: Operations in Africa, Asia, Australasia. Europe, North America and South America Golder, Golder Associates and the GA globe design are trademarks of Golder Associates Corporation Waste Management of Colorado 11 -October 2010 North Weld Landfill 2 103-81825 Runoff contributing to the site was assumed to be bounded by the fence line to the west, as there is a ditch on the westernside of the fence to intercept stormwater from the county road. Culvert sizing assumed smooth -wall corrugated HDPE culvert with a conventional entrance. CALCULATIONS Figure 1 presents the subbasin delineation and approximate locations of the affected perimeter channel reaches. Table 1 presents the area -weighted curve number calculations. Table 2 shows the time of concentration calculations but due to uncertainties in determining a defined flow path a conservative, minimum lag time of 3 -minutes was used. Table 3 includes a summary of the HEC-HMS model output. Table 4 provides channel geometry provided by Waste Management and flow information for the perimeter channels. The peak flow from the western runon area as determined from the HE -HIS model was conservatively added directly to the peak flows in the perimeter channels as reported in the RUST report. HY8 output for the culvert sizing calculations are presented as C. li,..)SIONS/RFSOLTS The HEC-HMS results indicate that the estimated 100 -year, 24 -hour peak flow from the western run-on area is 7 cubic feet per second. The HY8 results indicate that an 18 -inch diameter smooth wall HDPE culvert is adequate to pass the 7 cubic feet per second design flow. Based on the channel dimensions provided by Waste Management the additional peak flow will not adversely impact the as -designed perimeter channels. However, in order to provide adequate cover for the proposed culvert under the access road perimeter channel Reach 5-6 was steepened and Reach 6-7 was flattened to allow for a lower pipe invert elevation at the outlet, this change is reflected in Table 4. 04- TACHMENTS NT Attachment A - Travel Time, Manning's n, and Overland Flow Coefficients Attachment B - HEC-HMS Model Parameters Attachment C - HY8 Model Output HE -HMS Hydrologic Modeling System [computer software] August, 2009. US Army Corps of Engineers Version 8.4 U.S. National Oceanic and Atmospheric Administration (NOAA). 1973. Precipitation Frequency Atlas of the Western US, Atlas No. 2, volume ill - Colorado.. Silver Spring MD : US Department of Corn m erce. I.S. Federal Highway Administration (FHVVA). 200'x_ HY8 Version 7.2 FHWA Culvert Analysis. Washington, DC.: FHA Office of Technology Applications. U. S. Soil Conservation Service (USSCS). 1986. Urban Hydrology for Small Watersheds, 2nd edition (USSCS Technical Release Number 55). Washington D.O.: United States Department of Agriculture. J:11DJOBS'\1U3-B1875 NWLF Drainage Improvements\Surface waler\Runon H&H Calcula(ion.docx Golder Associates. IA10 C8:57 NUrhry I flaIICd: 1 I/ dJ10 t5tium MHialhey A1nrn4 rn3 4 411 DRAFT .7l 5120 r x 8 O N CNI z O IX In Us' U5 • I- z w ILI a z H J WO w V o -o J (75 < J C° LU Z zinc O O1 at ?P,..ECT Nv. 103-8162' No. NM f= C,iiv Basin REV. A SCALE AS SHOWN' DESICN' MBR ',0/35/10 CAC}n MBR 10/05/10 C-IECK REVIEW FIGURE 1 TABLE 't SUBBASIN SUMMARY TABLE Waste Management North Weld Landfill Project Number: 103-81825 Desion Storm 100 -Year Reccurence Interval Storm Duration (hours) 2 -Year Depth (inches) 100 -Year Depth I (inches) Storm Distribution 24 2.2 4.0 II Date: 1 11811 0 By:: MBR Chkd: Y le( Apprvd: Subbasin ID Subbasin Area (fk2} Subbasin Area (acres) Subbasin Area (sq mile) CN = 84 Composite SCS Curve No. S = 1000 - Unit Runoff Q (in) Runoff Volume (ac -ft) Runoff Volume (ft) Landfill Slopes (acres) 10 ON A 87,265 2.00 0.0081 2.00 CN = 84 1.90 2.37 0.40 17,243 Total: 87,265 2.00 0.00 0.40 17,243 J:11 DJOBS1103-81825 NWLF Drainage Improvements\Surface water\Runon H&H.xlsm Page 1 of 1 Golder Associates 11/8/2010 TABLE 2 BASIN TIME OF CONCENTRATION CALCULATIONS Waste Management North Weld Landfill Project Number: 103-81625 Date: `1:B.r1ti By: it R Chlttl: Alpi Lail) A pprvd: Flow Segment 1 Floe/ Segment 2 Flow Segment 3 / Subbasin IC l Subbasir Area I {sq mile) Composite Curve plumber Totat Lag (0.6`Te) (min) Total Travel Time (min) eype of Flow Length (t) I Slope Mitt) Roughness Conditicr(l) Tyrplcal Hydraulic ' Radius (Channel Only) (ft) Travel Time (min) I Type of Flow Length (ft) Slope , ift"ti Roughness 2endition{': Typical Hydraulic ' Radius (' hanr,el Only) ;ft) Travel Time (ruin) Type 04 How F Length (ft) Slope (Mt) Roughness Condition'" Tyaical Hydraulic Radius (Channel Only) (ft) Travel Time {min) A I 0.0031 84 15.4 253 Sheet 100.0 0.010 E Short Grass 15 6 Shallow 590_0 0.010 Li Unpaved 6,1 Channel 630 0.008 E Earth -lined 0.34 4.1 Notes: 1) Refer to A,tta;flrnen: A for Roughness Condition descriptions and To Cceffieciel,ts. J.t1JJOS I,111'1,-BS825 NVI/LF C'ra:najc Imrrnrr..wrrrFe rf v tenIct'.Rarnn HH.xis m Fags 1 of 1 Golder Associates 11/6;2010 TABLE 3 FLOW RESULTS FROM HE -HMS Waste Management North Weld Landfill Project Number: 103-81825 HEC-HMS Basin Model: HEC-HMS Met. Model: HEC-HMS Control Specs: Date: 1118110 By: MBR Chkd: 4 ' 7 vi MALe Apprvd: Western Runon 100 -year 24 -hour 48 -hr 5 -min Hydrologic Element Drainage Peak Area Discharge (sq mile) (cfs) Time of Peak Total Volume (ac -ft) A 0.0081 7.0 05Jun2020, 00:55 0.4 Page 1 of 1 Golder Associates J:11DJOBS\103-81825 NVVLF Drainage Impravements\Surface water\Runon H&H.xlsm 11/8/2010 ., Channel Hydraulic Calculations Waste Management North Weld Landfill PROJECT 103-81825 Date: 1118110 By: MDR _ Chkd: +lo "fie Apprvd: °� Reach Designation Estimated 10Q- year Flow Rate Ids) Channel Design Geometry Channel Roughness Parameters Hydraulic Calculations Channel Evaluations Bed Slope (ftlft) cleft Side Slope (H:1'V) Right Side Slope (H:1V) Bottom Width (ft) Minimum Channel Depth (ft) Design Channel Lining Mannings 'n" Mannings 'n' for Capacity for Stability (Depth I (Velocity Calculation} I Calculation) Nlaximunn Velocity (fusee) Maximum Normal Flow Depth (fl) I Fraud° Number Normal Depth Shear i Stress (Ib1Fts) Stream Top Width of Power Flow Mini} {ft) Top Width of Channel (ft) Available Freeboard {ft) S m C4 Reach 1 - 2. 24.0 0,015 2.0 2.0 3 3.0 G Grass -lined 0,035 0 030 4.7 1.10 0.97 1.03 701 7 4 15.0 1,9 Reach 2 - 3 24.0 0 009 2.0 2.0 3 3.0 G Grass -lined 0.035 I 0.030 3S 1.25 0.77 0.70 39.8 8 D 15.0 1.7 Reach :3 - b 24.0 0.006 2.0 2.0 3 3.0 G Grass lined 0.+335 3.4 1.38 D.63 0.52 25.3 •0.03D 87.0 8.5 15.0 1.6 Reach 5 0 Reach 6 - 7 35.0 0.014 2.0 2,0 3 3 0 G Grass -lined 0.035 0.030 5.1 1.35 0.95 1.18 8:4 1 8.3 15.0 1.8 35.0 0.015 2.0 2.0 3 3.0 G G Grass -lined 0.035 0.030 5.2 I 1.33 1.00 1.25 94.0 15.0 1.7 Reach 7-8 35.0 0.000+ 2.0 2.0 3 3.0 Grass -lined 0.035 0.030 3.7 1.67 I 0.65 0.62 33.0 9.7 15.0 1.3 Reach 8 - 9 39.0 0.045 2.0 2 0 3 3 0 R Riprap 0.040 0.035 7.1 1.14 1.45 3.20 331.6 7.6 _ 15.0 15.0 1.9 Roach 9 -10 _ 43.0 0.026 .2.0 2 0 3 3.0 3.0 R G Riprap 0.040 0.035 6.0 1.37 1.13 2.23 194.2 8.5 1.6 Reach 10 - 11 43.0 0.008 2.0 0.008 2.0 2.0 2.0 3 Grass -lined 0.035 11030 4.4 4.6 1.72 0.75 0.86 - 54.2 9.9 15.0 11.3 Reach 11 - 12 51.0 3 3.0 G Grass -lined 9.035 0.030 1.96 D.78 8 0.93 61.5 10.5 15.0 1.1 J:w1:LjfLlS11rri s1R75 NWL= 1}+amain Inrr+avernt3n24Slrn`I1G:ewnterlL2unnn I I.&?c 24 ism (1) Note: Comments and Warnings: < 1.0 Ft indicates freeboard is less than 1 foot. <1/2 Vel. Head indicates that the remaining freel:ward is less than 1/2 the velocity head 0/212g) suggesting water may splash our Warning: Vx.D>9 indicates that the velocity limns the depth is greater than 9 ft`Jsec, which is undesirable and may be u1 Unstable V indicates that calculated velocity exceeds the recommended maximum far the lining material. Unstable T indicates that calculated shear stress exceeds the reeomrnended maximum; for the lining material. P.rz"e 1 of 1 Colder Associates 11+'Sa'2010 Attachment A Travel Time, Manning's n, and Overland Flow Coefficients Attachment A Time of Concentration and Mannings Flow Coefficients TR-55 (1986) Sheet Flow Travel time (SCS Upland Method) Tt = 0.8 0,007 (n' L `F �0.5 S 0.4 � 2 Where: T1= travel time (hr); n' = roughness coefficient; L = flow length (ft); F2 = 2-yr storm depth (inches); s = slope (ft/ft) flow velocity = Lf(60TJ Flow Type Surface Type roughness n Surface Description Short Description sa r. 0 0 U) A B C 0 E F G H I J 0.011 Smooth surfaces (concrete, asphalt, gravel, bare soil) 0.05 Fallow (no residue) 0.06 0.17 0.15 0.24 0.41 0.13 0.40 0.80 Cultivated soils: Residue cover c= 20% Cultivated soils: Residue cover > 20% Grass: Short grass prairie Grass: Dense grasses Grass: Bermuda grass Range (natural) Woods: Light underbrush Woods: Heavy underbrush Smooth Fallow Coverc20% Cover>20% Short Grass Dense Grass Bermuda Grass Range Light woods Heavy Woods Shallow Concentrated Flow Velocity (SCS Upland Method) v = mS°.5 Where: v = veloci ty (fps); rn = roughness coeffient ; S = slope (ft/ft Flow Type Surface Type Roughness m Surface Description Short Description ° c - P 20.3282 Paved Surfaces Paved o U 16.1345 Unpaved Surfaces Unpaved .c L1 in� Channel Flow Veloci Mannings Velocity) v = 1.49/n Rh"Sz11 Where: v = veloci Mannings n Mannings n Lining Type for Depth for Velocity 0.026 0.026 C E G 1 P R 0.024 0.025 0.022 0.022 0.035 0.017 0.030 0.013 0.012 0.009 0.040 0.035 T z 0.035 0.030 0.060 0.005 (f is) Il=rou hness coeffient; Rh = Hydraulic Radius (ft), S = slo e (fttft) Material Maximum Velocity Maximum Shear Stress ACB CSP Earth -lined Grass -lined Ductile Iron Plastic Riprap Turf Reinf. Other 25 50 3 5 50 25 16 10 7 1.5 25 1 of Golder Associates Inc J:t10JOBS\103-81825 NV'VLE Drainage Improvements\Surface water\Runon H&H.xlsm 11/8/2010 Attachment B HEC-HMS Model Parameters Attachment B HEC-HMS Screen Captures and Inputs HEC-HMS Basin Model Schematic Basin Model [Western.Runanj Current. Run [100-yrearj asa ' AP ink. 1 tWi Sub Basin Area Subbasin Area (mil) A 1 0 003100 Loss SCS Curve Number Subbasin Initial Abstraction (in) Curve Impervious Number (%) A I 84 0 Transform SCS Unit Hydrograph Subbasin Lag Time (min) A 3 Pagel oft Golder Associates, Inc. J:U0JOSS1103-81625 MAILF Drainage lmprovements\Surface warerRunon HBH.xfsm 11/8/2010 Attachment C HY8 Model Output HY-8 Culvert Analysis Report Water Surface Profile Plot for Culvert: Culvert I Cltcissilizz- =1rossi1Y2 1 -Smooth HDPE., Deshzu Dischaisze - A cfs (_illl tel t ( :1111 el t 1. Cub -ells Disc:hai ge - 7.1) c' c 5132.0 5131.5 5131.0 0 5130.5 5130.0 W 5129.5 5129.0 5128.5 r 50 100 1 r I 1 I i 1 1 1 I I r 1 1 I 1 1 1 1 1 I 1 I I 250 15,,.+ 1200 150 200 Station (ft) 1 1 1 1 I r� 1 I I I 1 1 I 1 1 1 1 1 1 I 1 1 1 1 1 I . I I I I I I 1 I I I 1 I. I 1 I I Table I - Culvert Summary Table: Culvert I Total Discharge (cfs) Culvert Discharge (cfs) Headwater Elevation (ft) Inlet Control Depth (ft) Outlet Control Depth (ft) Flow Type Normal Depth (ft) Critical Depth (ft) Outlet Depth (ft) Tailwater Depth (ft) Outlet Velocity (Ws) Tailwater Velocity (ft/s) 0.00 0.00 5129.80 0.000 0.0* 0 -NF 0.000 , 0.000 0.000 1.300 0.000 0.000 0.70 0.70 5130.24 0.440 0.0* 1 -stn 0.248 0.309 0.249 1.300 3.551 0.000 1.40 1,40 5130.43 0.631 0.0* 1-S2n 0.358 0.442 0.361 1.300 4.231 0.000 210 210 5130.59 0.786 0.0* 1-S2n n 0.447 0.542 0.448 1.300 4.741 0.000 2.80 2.80 5130.73 0.926 0.0* 1-S2n 0.516 0.632 ' 0.522 1.300 5.097 0.000 3.50 3.50 5130.85 1.050 r 0.0* 1-S2n 0.585 0.711 0.586 1.300 5.468 0.000 4.20 4.20 _ 5130,97 1.168 0.0* 1-S2n 0.647 0.783 0.647 1.300 5.777 0.000 4.90 4.90 5131.09 1,288 0.0* 1-S2n 0106 0.848 0.707 1.300 5.975 0.000 5.60 5.60 5131.21 1.414 0.0" 1-S2n 0.765 0.912 0.765 1.300 6.185 a. 0.000 6.30 6.30 5131.35 1.551 0.0* 5-S2n 0.821 0.967 0.826 1.300 6.320 0.000 7.00 7.00 5131.50 1.702 - 0.0} 5-S2n 0.877 1.022 0.878 1.300 6.513 0.000 theoretical depth is impractical. Depth reported is corrected. Inlet Elevation (invert): 5129.80 ft, Outlet Elevation (invert): 5128.40 ft Culvert Length: 155.01 ft, Culvert Slope: 0.0090 Culvert Data Summary - Culvert 1 Barrel Shape: Circular Barrel Diameter 1.50 ft Barrel Material: Smooth HDPE Embedment: 0.00 in Barrel Manning's n: 0.0120 Inlet Type: Conventional inlet Edge Condition: Mitered to Conform to Slope Inlet Depression: None Table 2 - Downstream Channel Rating Curve (Crossing: Crossing 1 -Smooth HDPE) Flow (cfs) Water Surface Elev (ft) Depth (ft) 0.00 5129.70 1.30 0.70 5129.70 1.30 1.40 5129.70 1.30 2.10 5129.70 1.30 2.80 5129.70 1.30 3.50 5129.70 1.30 4.20 5129.70 1.30 4,90 5129.70 1.30 5.60 5129.70 1.30 6.30 5129.70 130 7.00 5129.70 1.30 Tailwater Channel Data a Crossing 1 -Smooth HDPE Tailwater Channel Option: Enter Constant Tailwater Elevation Constant Tailwater Elevation: 5129.70 ft Roadway Data for Crossing: Crossing 1 -Smooth HDPE Roadway Profile Shape: Constant Roadway Elevation Crest Length: 72.00 ft Crest Elevation: 5132.20 ft Roadway Surface: Paved Roadway Top Width: 100.00 ft APPENDIX B-4 Golder Associates CALCULATIONS Date: Project No.: Subject: Project Short Title: 14 -January -2013 123-82269 Supplemental H&H Calculations Revision 1 NWLF Drainage Improvements Made by: MBR Checked by: et",, Reviewed by: 1.0 OBJECTIVES This calculation serves as a supplement to the Engineering Design and Operations Plan (EDOP) prepared by RUST (RUST, 1995) to document changes to the hydrology and hydraulics calculations. In this revision the calculations originally prepared by Golder in 2010 are updated to reflect changes to the landfill perimeter channel as a result of the proposed liner grading associated with the construction of Phase 3a Module 3. Additionally, a culvert has been sized for an access road crossing over the perimeter channel, and the perimeter channel riprap revetment has been re -analyzed. Peak 100 -year, 24 -hour stormwater flowrates for the landfill were calculated in a previous calculation (RUST, 1995). This memorandum estimates a 100 -year, 24 -hour peak flow contributing to a point upgradient of the maintenance shop area which is subsequently added directly (no routing) to the flowrates provided in the RUST calculation to determine if the as -designed perimeter channels will be adequate to accommodate the additional runoff. ao METHODS The contributing basin for the maintenance shop area was delineated based on site topography, see Figure 1. SCS Curve Number (CN) methodology was used to estimate runoff from this area. Parameters including subbasin area, CN, lag time, and slope were entered into HEC-HMS to develop a peak flow. Attachment A presents the manning's n and overland flow coefficients. A routing diagram displaying the routing logic is included in the attached HEC-HMS output (Attachment B). Revised channel dimensions provided by Waste Management (Figure 2) were analyzed using a spreadsheet that solves for normal depth using manning's equation to verify that the additional stormwater flows determined in this calculation would not cause overtopping. Culvert sizing was performed using HY8 culvert sizing software (FHWA, 2009). .0 DATA AND ASSUMPTIONS ® NOAA Technical Atlas 2 precipitation depths (NOAA, 1973): TN- Ita. Aril Return (years) Period Precipitation (inches) Depth 2 17 100 4.0 The rainfall hyetograph assumed an SCS Type II storm distribution. Basin A lag time assumed to be 3 minutes (for consistency with previous calculations). SCS Curve Number was assumed to be 84 for consistency with the RUST calculations J:l12JOBS1123-82269 NWLF Perimeter ChannefkRurion H&H Calculationtlocx Golder Associates Inc. 44 Union Boulevard, Suite 300 Lakewood, CO 80228 USA Tel: (303) 980-0540 Fax: (303) 985-2080 www.goldercom Golder Associates: Operations in Africa, Asia, Australasia, Europe, North America and South America Waste Management of Colorado North Weld Landfill 14 -January -2013 123-82269 Manning's roughness coefficients: Channel Lining/Material Manning's n for Capacity Manning's n for Stability Grass 0.030 0.033 TRM 0.030 0.035 HDPE (culvert) 0.012 0.012 • Runoff contributing to the site was assumed to be bounded by the fence line to the west, as there is a ditch on the western side of the fence to intercept stormwater from the county road. • Culvert sizing assumed smooth -wall corrugated HOPE culvert with an entrance mitered to match the fill slope. i Maximum allowable peak flow velocity in the perimeter channel with grass lining is assumed to be 5.5 ftis. Channel reaches with peak velocities in excess of 5.5 Ws will be lined with TRM. 4.0 CALCULATIONS Figure 1 presents the subbasin delineation and approximate locations of the affected perimeter channel reaches. Table 1 presents the area -weighted curve number calculations. Table 3 includes a summary of the HEC-HMS model output. Table 4 provides channel geometry provided by Waste Management and flow information for the perimeter channels. The peak flow from the western runon area as determined from the HEC-HMS model was conservatively added directly to the peak flows in the perimeter channels as reported in the RUST report. 5.0 CONCLUSIONS/RESULTS The HEC-HMS results indicate that the estimated 100 -year, 24 -hour peak flow from the western run-on area is 7 cubic feet per second (cfs). The HY8 results indicate that an 18 -inch diameter smooth wall HDPE culvert is adequate to pass the 7 cfs design flow for the main haul road culvert with a headwater of 1.7 ft above the culvert invert and a 36 -inch diameter smooth wail HDPE culvert is adequate to pass the 24 cfs design flow for the access road crossing of the perimeter channel with a headwater of 2.4 ft above the culvert invert. Based on the channel dimensions provided by Waste Management, the additional peak flow will not adversely impact the as -designed perimeter channels. A summary of the estimated design flows and subsequent flow velocities is presented in the following table: Reach I.D sidslope Width Bottom (ft) Depth (ft) Lining 100 Peak (cfs) -year Flow 100 -year Velocity (fps) Peak 2H:1V 3 Grass 24 4.3 2H:1V 3 35 6.0 TRM 77±81 3 10 2H:1V 3 3 Grass 35 4.9 — 10 12 2H:1V 3 TRM 35 3.4 — 12-15 2 H: 1 V 3 3 Grass 43 5,4 15•-16 2H:1V 3 3 TRM 5.6 5P1 asts Management of CSarado North V1/2 I r_ Landfill �ican',, A le -:2 013 123-82269 6.0 LIST OF ATTACHMENTS Attarthririsra A Tr a n?.l Time. Mannin 's n, and Overland Flow Coefficients Attachment B - H EC -HMS Model Parame ers Attachment C - H'YF Mndel Output TO REFERENCES HEC-HMS Hydnologic Modeling Sy si [computer sc'fi'i arej August, 2009. US Army Corps of Er-gireers version 3,4 ,.i atir ri t Ottariic :and Altrimiptielic Administration (NO ..�Q. 1073. Preci ita'tt'r' Frequency Atlas of the 151em U4 ., Mas I'M. 2, volume. Ill - Cal:_Drat t. S 'Pier tpr: n!-_-1 MD : Department of Can it site. U.S,rmy Corps of Eni m'leers (LISAGE). 1994, fvdr3Lt',1t of Mrs .1.1 j Corirrol lil'a ,ric) . Engineer Manu i `1.t .1 C'-2-1 f„= r 1. Department ent {a= the Army. 'rx'i a5hi'.n ton Lin:fed 1a e ` over'ri % 'it Printing 'Office. U.S. Faders' Highway Administration (FHWA). 2109. HAT Ver5von `. 2 FifilW A CIL. err Aralysis. 4 itshin .ton, DC. FHA Office of Technolog Applications. LI. S. Sail :-n 1s ervata n Se n i ce ( US S ). 1D86. ..Urban Hyd4i gv :r -,.r `. , a i.i f ?ersh a rim (USSCS I oche K:al I '.base Number 55). Vi.i shiriglorn D.C.: United is as Departrueni of Agriculture. -a.- - EL-im 0 ... I J•9. -t- - -2-- J-- r�- II II ! y:-i; ! II I / I b I I 4, .,3 f. �,. F. rr I �I i I I 11 f I 2 g' f I • I of r or I I II I I I Sit/ it I I II -5180----- - 5150 er eeer as_ / it r • 1 ti • • 5100 aa aam ol • 8 51501-- IP.f : I,I I of. Mle L X • ift • aim _ 00L0 01 kg OZ IS sir aLvERT fr fir O -a LEGEND 12 EXISTING TOPOGRAPHY PERIMETER CHANNEL ALIGNMENT PERIMETER CHANNEL REACH • BASIN BASIN BASIN DESIGNATOR DELINEATION Ara te- • • , _ lass Ron xcut_veRgq Si s. yr I .+ ree-/ 020 a cdo to rec: oite 0 7) 8 Er; 5 z LLI PHU CI No. 10.3-Mnritt DESGN MISR 'ID/0.5/1C CFECK FIGURE 1 1 a i 4 i i i i i i 15 LEGEND 16 12 250 1 _ 250' PROPOSED LINER GRADE TOPOGRAPHY PERIMETER CHANNEL ALIGNMENT PERIMETER CHANNEL REACH I• D. 250 WASTE MANAGEMENT NORTH WELD LANDFILL 500 Feet REVISED CHANNEL ALIGNMENT AND LANDFILL LINER GRADES Golder _Associates PROXCT Nu. m23-82268 CrFSGr ?ERR 12/14/12 ADO MDR 12/14/12 CHECK 12/14/12 9EME1! 12/14/12 plc #la. u..r.rori MN SCALE N/A 1 REV. FIG2 TABLE 't SUBBASIN BASIN U MMARY TABLE Waste Management North Weld Landfill Project Number: 103-81825 Design Storm 100 -Year Reccurence Interval Storm Duran (hours)24 2 -Year Depth (inches) 2.2 100 -Year Depth (Inches) 4,0 Storm Distribution I I Subbasin ID A Total: Subbasin Area (ft2) 87,265 87,265 J:ti10JOBS\1o3-81825 NWLF Drainage improver enteSurfaco waterdiunon H$W.xksm Subbasin Area (acres) 2.00 2.00 Subbasin Area (sq mile) 0.0031 0.00 CN = 84 Landfill Slopes. Date: 11/8110 By: _ MBR Chkd: Apprvd: iet Composite SCS Curve No. S = 1000 - Unit Runoff 10 n (in) Runoff Volume (ac -ft) Runoff Volume (& Page Ioft Golder Associates CN=84 0.40 17.243 0.40 17.243 11/8/2010 TABLE 3 FLOW RESULTS FROM HEC-HMS Waste Management North Weld Landfill Project Number: 103-81825 HE -HMS Basin Model: HEC-HMS Met. Model: HEC-HMS Control Specs: Date: 1118110 By: MBR Chkd: Vi7 Appryd; - Western Runon 100 -year 24 -hour 48 -hr 5 -min Hydrologic Element ' Drainage Peak Area Discharge (sq mile) Ws) Time of Peak Total Volume (ac -ft) 0.0031 7.0 05Jun2020, 00:55 0.4 Page .1 of 1 Golder Associates J:110JOBS\10'3-81825 NWLF Drainage Improvements\Surfaca water\Runon Heel xlsm 1118/2010 Table 4 Channel Hydraulic Calculations Waste Management North Weld Landfill PROJECT 123-82289 Date: 1/14113 By:: MGR V Chkd: c/"" Appnrd i /'S ChannelDeal Geometry Channel Roughness Parameters a rauftc Calculations Channel Evaluations Reach Desi atlon f2. Estimated 100 -year Flow Rate (cfs) ' Bed Slope (tt/k) Left Side Slops ; (H:1V) Right Side Slope (H:WV) Bottom Width (ft) i Minimum Channel Depth (It) Design Channel Lining Meanings in' F for Capacity pa ty (Depth Calculation) Mannings In for Stability (Velocity • Calculation) Maximum Velocity (ftisoc) Maximum m Normal Flow Depth (ft) Fraude Number Normal Depth Shear Stress (Ibfft?) Stream I Power j (MO i Top Width of Flow (ft) Top Width of Channel (ft) Available Freeboard (ft) 24.0 0:016 -2.11----,....% 3.4 G Grass -lined 0035 0_ t30 4.7 1.10 I 0.97 1.03 70.1 74 15.0 1.9 `Bch Reach 2 -3 24.0 0O09 2.0 2.0 3 3.0 -1---d-1 Grass -!rued _0.035 _ j 0,030 3.5 1.25 0.77 ) 0.70 398 6.0 15.0 1.7 ) g Reach 3 - 5 24.0 0.006 _ 2.0 2.0 3 3.0 G Grass -fined 0.035 0.030 3.4 1.38 0.83 0.52 25.3 8.5 15.0 1.6 I. Roach 5 - la /4.0 0.012 2.0 -7 10 3 3.0 G Grass -lined 0.035 0.030 4.4 1.15 0-89 0,89 55.8 7.6 15,0 1.8 = Reach 8 - 7 24.0 0.016 2.0 2.0 3 3,0 G Grass -lined 0,035 0.030 4.8 1,09 1.00 1.07 74.2 7.3 - - 16.0 1.9 d ,Reach 7 - 8 35.0 0.022 2.0 2.0 3 3.0 T Turf Reinf. D.035 11030 B_0 1.21 - 1,19 1.68 144.0 1.8 " 15.0 1.8 cm Reach 8 - 9 35.0 0.013 2.0 2.0 3 3.0 G Grass -lined i 0.035 0.03D 4.9 1.39 0.92 1.09 77.3 8.6 i 15.0 1.6 a Reach 9 -10 35.0 0.007 2.0 J 2.0 3 3.0 G Grass lined 0.035 0-034 3.9 1.60 0.70 0.70 40.0 9.4 15.0 1.4 ,4 Reach 10 - 11 35.0 0.037 2,0 2:0 3 3.0 T j Turf Reid. 0.035 0.030 7.2 1.06 1.52 2.45 256.9 7.2 15.0 1.9 : Reach 11 - 12 35.0 _ 0056 2.0 2.0 3 3.0 T ' Turf Rainf. 0.035 0.430 8.4 0.95 1.85 3.32 404.4 6.8 15.0 2.0 } Reach 12 - 13 1 39.0 j 0.013 2.0 2.0 3 3.0 G Grass-Ilned 4.035 0.030 6.1 1.45 0,94 1.18 87.0 8.8 15.0 1.5 & Reach 13 -14 43,0 0.013 2.0 2.0 3 3.0 + G Grass -lined 0.035 0.030 5.2 1.53 0.94 1.24 93.6 _ _ 9.1 16.0 1.5 Reach 14-15 43.0 0.014 2.0 ' 2.0 3 3.0 C Grass -lined 0.035 0.030 5.4 1.50 0.98 1.31 101.8 9.0 1 15.0 1,5 Reach 15 - 16 51.0 I 0.014 2.0 2.0 3 3.0 T Turf Reid. 0.035 ` 0.030 5.6 1.63 0.99 1.42 1 115.7 9.5 l 15.0 - I.4 J:112.J0B 1123-822e9 NWLF PercneterChanneP.Runon H&H.glam Page 1 of i Golder Associates 1) Note; Comments and Warnings: c 1.0 ft indicates freeboard is less than 1 foot. { 1/2 Vol. Head indicates that the remaining freeboard is less than 112 the velocity head (V212g) suggesting water may splash out. Warning: VxD>9 indicates that the velocity times the depth is greater than 912/sec, which is undesirable and may be u Unstable V indicates that calculated velocity exceeds the recommended maximum (or the lining material. Unstable T indicates that calculated shear stress exceeds the recommended maximum for the lining material. 1/14/2013 Attachment A Travel Time, Manning's n, and Overland Flow Coefficients Attachment A Time of Concentration and Mannings Flow Coefficients TR-554(1986) Sheet Flow Travel time (SCS Upland Method) 0.007 (a' L )(18 �a5 S. l(P2 Where: Tt = travel time (hr); n' = roughness coefficient; L = flow length (ft); P2 _ 2-yr storm depth (inches); s = slope (ft/fl) flow velocity = U(60T1) Flow Type r Surface Type roughness n Surface Description short Description ShootlOverland Flow A B C O F G H i J 0.011 Smooth surfaces (concrete, asphalt, gravel, bare soil) 0,05 Fallow (no residue) 0.06 Cultivated soils: Residue cover a 20% 0.17 Cultivated soils: Residue cover > 20% 0.15 'Grass: Short grass prairie 0.24 Grass: Dense grasses 0.41 Grass: Bermuda grass 0.13 Range (natural) 0.40 Woods: Light underbrush 0.80 Woods: Heavy underbrush • Smooth Fallow Cover<20% Cover>20 % Short Grass Dense Grass Bermuda Grass Range Light woods Heavy Woods Shallow Concentrated Flow Velocity (SCS Upland Method) v = mSn Where: v = velocity (fps); in = roughness coeffient; S = slope (Mt) Flow T e Surface Type Rou hness m : Surface Description Description i 'Lining Type , for Depth for Velocity A 0.026 , 0.026 0.024 ` 0.022 0.025 - - ` 0022 ©.035 0.030 0017 0.013 G T Z 0.012 0.009 0.040 0.035 0.035 1_ 0.030 0.060 0.005 U 20.3282 Paved Surfaces 16.1346 Unpaved Surfaces Paved Unpaved Channel Flow Velo Mannings Velocity) v = 1.49/n Rhi S„' - - Where: v = velocity (fps); n = roughness coeffrentr Rh = Hydraulic Radius in. S ! slope (ft1ft ' Meanings n Mannings n _ rMaximum t -Maximum Material Velocity Shear Stress ACS CSP Earth -lined Grass -lined Ductile iron Plastic Riprap Turf Reinf. Other 1 of 1 Golder Associates Inc J:1I0JOBS1103-81825 NWIF Drainage ImprovementslSurface water%Runan Ff&H.xrsm 25 50 3 5 5b 25 16 10 25 1.5 11/8/2010 Attachment B HEC-HMS Model Parameters Attachment B HEC-HMS Screen Captures and Inputs HECIHMS Basin Model Schematic Sub Basin Area Subbasin Nir A 0,003100 • Area I (mi'f Loss SCS Curve Number I Initial , A,bstra ct€on Curve impe r vi o us I, (nit Number (%) 8d 0 Subbasin A Transform SCSUnitWdrorah Subbasin A Lag Time (min) 3 Page 1of1 Golder Associates, inc. J11DJOBS1103-91825 MWLF Drainage Improvcmenlw%Surface water\Runon HAH,)dsm 11/8/2010 Attachment C HY8 Modes Output HY-8 Culvert Analysis Report Water Surface Profile Plot for Culvert: Culvert a1 Crossing - Crossi _ . 1 -mooch HDPE, Des Disehaite - 7.0 cTh Culvert - Culvert 1, Culvert Discharge - 7.0 efts 5132.0 5131.5 C 5131 0 151305 0> 5130.0-7_ AMIEW Wag dad I e I 4 r I I I I I ...01S -ra -_-- a ...ma,.�ai 1aa tam mar 5129.5-7 r 5129.0 j 4.. 5128.5 rz S 50 I I 1 1 I I I L I 1 1 1 1 1 1 1 1 I 1 r 1 I I I 4 I 1 1 I r L I 1 I 1 1 I 1 1 I I I I I 1 I 1 I 1 1 1 I 1 e 1 I 1 $ I I 1 1 1 : r e e r r 1 a i I I I I I I I I I `I i p a a a a_ a I 1 I 1 I I I 1 I -I-_-------raa a _ _Ora -.tars---------E 1 1 1 1 I -1. _ 100 150 200 Station (ft) 250 ti I I I I I I I I I I 1 300 1 Table I Culvert Summary Table: Culvert I Total Discharge cfs) Culvert rt Discharge afs Headwater Elevation (ft) Inlet antral Depth eft) Depth �tl t Corttr�al (ft) Flaw Type Normal Depth (ft) critical Depth (ft) Cutlet Depth (ft) Taitwater Depth (ft) Outlet Velocity (ft/5) Taliwator Velocity 0.00 0 00 5129.80 0.000 0.0* 0 -NF 0.000 0.000 0.000 1300 0.000 0.000 070 5130.24 0.440 0.0' 1-52n 0.248 0.309 0.249 1.300 3.551 0.050 0.70 1.40 1.40 5130,43 0.631 D.0* 1-S2n 0.358 0.442 0..351 1300 4.231 0,000 2.10 210 5130.59 0.786 0.0' 0.447 0.542 0.445 1.300 4.141 0.000 2.80 2.80 5130.73 0.926 0.0' 0.516 0.632 _ _ 0.522 1.300 5.097 0.000 + 3.50 513085 1.050 0.0` 0.585 0.711 0.586 1.300 5.468 0.000 4.20 420 1168 0.0* 0 647 0.783 1.300 0.000 5130.97 5.777' 4.90 4.90 5131.09 1.288 0.0` 12n 0.706 0.848 0.707 1.300 5.975 0.000 5.60 5.60 5131.21 1.414 O.Ot 1 -S 2n 0.7650.912 0.765 1.300 0.000 6185 6.30 6.30 5131.35 1.551 0.0* 5-S2n 0.821 0.967 0.826 1.300 6.320 0.000 7.00 7.00 5131.50 1.702 0.0* 5-52n 1.022 0.878 1.300 6.513 0.000 0.877 * theoretical depth is impractical. Depth reported is corrected. Inlet Elevation (invert): 5129.80 ft, Outlet Elevation (invert): 5128.40 ft Culvert Length: 155.01 ft, Culvert Slope: 0.0090 AbA****rtt&-* Rtt **f *******tit!twt#nertt*4i-kiti-tip*t*i&ar****flt*grt*-*flti* Culvert Data Summary - Culvert I Barrel Shape: Circular Barrel Diameter 1.50 ft Barrel Material: Smooth HDPE Embedment: 0.00 in Barrel Manning?s n: 0.0120 Inlet Type: Conventional Inlet Edge Condition: Mitered to Conform to Slope Inlet Depression: None Table 2 - Downstream Channel Rating Curve (Crossing: Crossing 1 -Smooth HDPE) Flow (cfs) Water Surface Elev (ft) Depth (ft) 0.00 5129.70 1.30 0.70 5129.70 1.30 1.40 5129.70 1.30 2.10 5129.70 1.30 2.80 5129.70 1.30 3.50 5129.70 1.30 4.20 5129.70 1.30 4.90 5129.70 1.30 5.60 5129.70 1.30 6.30 5129.70 1.30 7.00 5129.70 1.30 Tailwater Channel Data - Crossing 1 -Smooth HDPE Tailwater Channel Option: Enter Constant Tailwater Elevation Constant Tailwater Elevation: 5129.70 ft Roadway Data for Crossing: Crossing 1 -Smooth HDPE Roadway Profile Shape: Constant Roadway Elevation Crest Length: 72.00 ft Crest Elevation: 5132.20 ft Roadway Surface: Paved Roadway Top Width: 100100 ft HY-8 Culvert Analysis Report Water Surface Profile Plot for Culvert: Culvert 131 Crossing a Access Crossing, Design Dischargea 31.0 els Culvert - Culvert 1.,: Culvert Discharge - 31.0 -cg`s 5136 5135 5134 5133 5130 5129 1 I J � I uf, i -20 20 40 60 80 Station (if) 100 120 Table I - Culvert Summary Table: Culvert PI Total Discharge (cfs) Culvert Discharge (cfs) Headwater Elevation (ft) Inlet Control Depth (ft) Outlet Control Depth (ft) Flow Type Normal Depth (ft) Critical Depth (ft) Outlet Depth (ft) Tailwater Depth (ft) Nutlet Velocity (ft/s) Tailwater Velocity (ft/s) 0.00 0.00 5132.50 0.000 0.0* 0 -NF 0.000 0.000 0.000 0.000 0.000 0.000 3.10 3.10 5133.27 0.768 0.0* 1-S2n 0.311 0.535 0.325 0.381 8.485 2.159 6.20 6.20 5133.61 1.106 0.0* 1-S2n 0.415 0.769 I 0.429 0.562 9.665 2.675 9.30 9.30 5133.87 1.374 0.0* 1-S2n 0.519 0.957 0.527 0.701 10.928 3.014 12.40 12.40 5134.11 1.611 0.0* 1-S2n 0.615 1.111 0.620 0.817 I 11.827 3.273 15.50 15.50 5134.33 1.829 0.0* 1-S2n 0.679 1.252 0.682 0.919 12.130 3.485 18.60 18.60 5134.53 2.027 0.0* 1-52n 0.743 1.374 0.764 1.010 12.986 3.667 21.70 21.70 5134.71 2.214 0.0* 1-S2n 0.808 1.497 0.819 1.094 13.796 3.825 24.80 24.80 5134.90 2.399 0.0* 1-S2n 0.872 I. 1.600 0.924 1.171 13.432 3.966 27.90 27.90 5135.09 1 2.587 0.0* 1-52n 0.928 1.703 0.935 1.242 14.884 4.095 31.00 31.00 5135.28 I 2.783 0.0* 1-S2n 0.977 1.804 1.047 1.310 14.062 4.212 *******'h'J4******7k7 ***9k*****51tYY***** ***************Mfr**1FdFdkai********de*i ***ak*****drab*** Inlet Elevation (invert): 5132.50 ft, Outlet Elevation (invert): 5129.10 ft Culvert Length: 100.06 ft, Culvert Slope: 0.0340 ***********.*************,***************************************************** Site Data - Culvert 1 Site Data Option: Culvert Invert Data Inlet Station: 0.00 ft Inlet Elevation: 5132.50 ft Outlet Station: 100.00 ft Outlet Elevation: 5129.10 ft Number of Barrels: 1 Culvert Data Summary - Culvert I Barrel Shape: Circular Barrel Diameter: 3.00 ft Barrel Material: Smooth HDPE Embedment: 0.00 in Barrel Manning's n: 0.0120 Inlet Type: Conventional Inlet Edge Condition: Mitered to Conform to Slope Inlet Depression: NONE Table 2 - Summary of Culvert Flows at Crossing: Access Crossing Headwater (ft) Elevation , Total Discharge (cfs) Culvert 1 (cfs) Discharge Roadway (cfs) Discharge Iterations 5132.50 0.00 0.00 0.00 1 5133.27 3.10 3.10 0.00 1 5133.61 6.20 6.20 0.00 1 5133.87 9.30 9.30 0.00 1 5134.11 1 12.40 I 12.40 0.00 1 5134.33 15.50 15.50 0.00 1 5134.53 18.60 18.60 0.00 1 5134.71 21.70 21.70 0.00 1 5134.90 24.80 24.80 0.00 1 5135.09 27.90 27.90 0.00 1 5135.28 31.00 31.00 0.00 1 5136.40 45.35 45.35 _ 0.00 Overtopping Table 3 - Downstream Channel Rating Curve (Crossing: Access Crossing) Flow (cfs) Water Surface Elev (ft) Depth (ft) Velocity (ft/s) Shear (psf) Froude Number 0.00 5129.10 0.00 0.00 _ 0.00 1 0.00 3.10 I 5129.48 0.38 2.16 0.30 0.68 6.20 5129.66 0.56 2.68 0.44 i 0.71 9.30 5129.80 0.70 3.01 0.55 0.73 12.40 5129.92 0.82 3.27 0.64 0.74 15.50 5130.02 0.92 I 3.49 0.72 0.75 18.60 A 5130.11 1.01 3.67 0.79 0.76 21.70 5130.19 1.09 3.82 0.86 0.77 24.80 5130.27 1.17 3.97 0.92 0/7 27.90 5130.34 1.24 4.09 0.98 0.78 31.00 5130.41 1.31 4.21 1.03 0.79 Tailwater Channel Data - Access Crossing Tailwater Channel Option: Trapezoidal Channel Bottom Width: 3.00 ft Side Slope (H:V): 2.00 (_:1) Channel Slope: 0.0120 Channel Manning's n: 0.0350 Channel Invert Elevation: 5129.10 ft Roadway Data for Crossing: Access Crossing Roadway Profile Shape: Constant Roadway Elevation Crest Length: 80.00 ft Crest Elevation: 5136.40 ft Roadway Surface: Gravel Roadway Top Width: 20.00 ft APPENDIX B-5 Golder Associates September 22, 2016 Ms. Hayley Brown Weld County Engineering 1555 N. 17th Avenue Greeley, CO 80631 Project No. 1538880 RE: SUPPORTING HYDROLOGIC AND HYDRAULIC CALCULATIONS; NORTH WELD LANDFILL PAVING IMPROVEMENTS Dear Ms. Brown: On behalf of Waste Management Disposal Services of Colorado, Inc. (WMDSC), Golder Associates Inc. (Golder) is pleased to provide Weld County Engineering (the County) with this letter summarizing the hydrologic and hydraulic calculations performed in support of the proposed paving improvements at the North Weld Landfill. As previously discussed between the County and WMDSC, WMDSC plans to pave approximately 1,000 feet of the main haul road along the west side of the landfill. Golder understands that the County requested additional information on potential drainage impacts on site drainage structures related to the increase in impervious area. On September 6, 2016, Senior Engineer Tom Schweitzer with WMDSC provided the County with a letter providing historical information on the design (storage capacity) and construction of the existing stormwater retention pond that ultimately receives stormwater runoff from the haul road to be paved. In response, the County requested additional hydrologic calculations supporting the proposed paving improvements. This purpose of this letter is summarize the scope and results of the hydrologic and hydraulic calculations performed to support the paving improvements. 1.0 STORMWATER MANAGEMENT SYSTEM DESIGN The stormwater management system for the North Weld Landfill was designed as part of the development of the Updated Design and Operations (D&O) Plan for the North Weld Sanitary Landfill originally prepared by Rust Environment & Infrastructure, Inc. in January 1996, and revised by WMDSC in November 1997. Runoff from closed landfill slopes and surrounding run-on areas is collected by permanent perimeter channels and conveyed to a retention pond located in the southeastern corner of the property. The highpoint of the property is in the northwest corner. Runoff from the primary haul road is initially collected in the western perimeter channel, as shown in the attached Figure 1. In 2010, Golder modified the facility hydrologic and hydraulic calculations to capture stormwater runoff from west of the primary haul road and convey it to the landfill perimeter channel via an 18 -inch culvert crossing beneath the primary haul road (Golder 2010). Golder subsequently modified the calculations again in 2013 to replace approximately 100 feet of perimeter channel with a 36 -inch -diameter culvert to allow for the development of a landfill access road across the channel alignment and to incorporate several changes to the perimeter channel alignment as a result of as -built liner grading plans (Golder 2013). The locations of these culverts are shown in the attached Figure 1. i:1151153888010100101101haul rd imp. 22sep1611538880 Itr fni nwlf haul rd improvements 22sep16.docx Golder Associates Inc. 44 Union Boulevard, Suite 300 Lakewood, CO 80228 USA Tel: (303) 980-0540 Fax: (303) 985-2080 www.golder.com Golder Associates: Operations in Africa, Asia, Australasia, Europe, North America and South America Golder, Golder Associates and the GA globe design are trademarks of Golder Associates Corporation Ms. Hayley Brown September 22, 2016 Weld County Engineering 2 1538880 2.0 HYDROLOGIC AND HYDRAULIC CALCULATIONS 2.1 Scope As the new paved section of the haul road will report to the culverts and perimeter channels, the affected channel sections and culvert crossings were re-evaluated to demonstrate that the structures will have sufficient conveyance capacity. As the perimeter channel discharges into the existing retention basin in the southeast corner of the property, the increased runoff volume was also estimated in order to verify that the basin will have sufficient storage capacity. 2.2 Methodology Drainage basins along the main haul road, which include the proposed pavement area, were delineated using site topography provided by WMDSC. The paved roadway was assumed to be crowned perpendicular to the centerline, with runoff from one basin (Al) draining west off the pavement, then south through a drainage ditch and ultimately reporting to the existing 18 -inch high -density polyethylene (HDPE) culvert under the haul road and the other basin (A2) draining east off the pavement into the landfill perimeter channel and continuing south to the existing 36 -inch HDPE culvert under the landfill access road. Consistent with the original hydrologic calculations, the Soils Conservation Service (SCS) methodology was used as the basis of the hydrologic modeling. SCS curve numbers and rainfall data were referenced from the previous Colder calculations (Colder 2010 and 2013). HEC-HMS (USAGE 2013) software was used to calculate peak discharges. For hydraulic analysis of the perimeter channel, Manning's equation flow calculation spreadsheets previously used for the channel design were updated for the purposes of this modification. The Federal Highway Administration's HY-8 culvert analysis program (FHWA 2014) was used to evaluate capacity of the previously -deigned culvert crossings. 2.3 Results The results of the HEC-HMS hydrologic analysis are presented in Table 1 below. Table 1: Peak Discharge Summary Basin Drainage Area (acres) Basin Imperviousness (%) 100-Yr, 24 -Hr Peak Discharge (cfs) Al (West) 2.2 14 7 m A2 (East) 2.2 21 6 Due to a lack of detail provided in the original design calculations and supporting figures presented in the D&O Plan, it is unclear whether runoff from the main haul road and surrounding area west of the road was included in the original channel design. Therefore, it was conservatively assumed that these basin areas along the haul road and corresponding peak flows were not previously included in the areas and runoff volumes presented in the 1997 D&O Plan. As such, the calculated peak flows presented in Table I were added directly (no routing) to the perimeter channel flowrates provided in the 1997 calculations to determine if the as -designed perimeter channels and culvert crossings are adequate to accommodate the additional runoff from the pavement improvements. All channel reaches and culvert inlets as currently sized and constructed have adequate capacity to accommodate the additional discharge from the paved haul road and surrounding runoff areas shown in Figure 1 while maintaining a minimum of one foot of available freeboard. The additional discharge will result in an increase in total runoff volume of approximately 1.0 acre-feet requiring storage in the retention basin. As outlined in the retention basin documentation previously provided to the County by WMDSC, the design runoff volume reporting to the basin is 22.6 acre-feet prior i:115\153888th010010110\haul rd imp. 22sep16\1538880 Itr fnl nwlf haul rd improvements 22sep16.docx a Golder AssocIates Ms. Hayley Brown September 22, 2016 Weld County Engineering 3 1538880 to the pavement improvements work. Conservatively assuming that the runoff from the main haul road and surrounding area west of the road was not previously included in the basin design, the total estimated runoff volume requiring storage will be 23.6 acre-feet. As constructed, the available volume for stormwater retention in the basin is 42.2 acre-feet (10.8 acre-feet set aside for sediment storage in the design calculations and 31.4 acre-feet of stormwater storage). This available storage volume does not include the storage volume set aside for maintaining one foot of freeboard (7.1 acre-feet) per Weld County Code requirements. Complete versions of the supporting hydrologic and hydraulic calculations are not attached to this letter. Complete copies of the calculations can be submitted to the county if required upon request. Please let me know if you have any questions regarding these calculations. Best Regards, GOLDER ASSOCIATES INC. Jeff Rusch, FE Senior Engineer cc: Tom Schweitzer, Waste Management Disposal Services of Colorado, Inc. Bill Hedberg, North Weld Landfill Kim Ogle, Weld County Planning Enclosures: Figure 1 J.Ia p i.\18',153888010100\01101baul rd imp. 22sep16\1538880 1588880 Itr-fnl nwff haul rd improvements 22sep16.docx Golder Associates FIGURE 1 LI\ ti! _ xNil 'gawp - t N I PlAIN HAUL ROAD CULVERT CS in I-DPEi.- r ACCESS ROfi.D CLLVERT (36 in HDPE) N — r - LEGEND —a- goo EXISTING GROUND CONTOUR ;ft -IV84 FXI5TING R0Af1S PEHI ME —ER CI IAN N EL ALIGNMENT 2 PERIME—ER CHANNEL REACH LOCATIC:4., AND ID RA IN FIFI INFATI0N PROPOSED IIAJL ROAD PAVED AREA CONCENTRATION 'DINT BASIN ID 4 WATERS! !ED AREA (ACRES) I"= .iiOC' FEET CLILN I lotif aim INANTE RIANDISEEMINT PROJECT NORTH WELD LANDFILL WELD COUNTY COLORADO MAIN HAUL ROAD IMPROVEMENTS f TITLE Airci RUNON BASIN DELINEATION AND SELECT PERIMETER CHANNEL LOCATIONS CONSUL IANI YYYY-MM-DD 201C -D9.21 DESIGNED SPS PRFPARFD J-IR RFVIFWFFJ APPROVED JAR PROP CT NO. CON T R{OI 1538880 0002 RFV. A FIt;LJRF 1 W T 4 1 ; z no Y 2 r T 1 APPENDIX E CONSTRUCTION QUALITY ASSURANCE (CQA) PLAN A world of capabilitie delivered local) CONSTRUCTION QUALITY ASSURANCE (CQA) PLAN North Weld Landfill Weld County, Colorado Prepared By: Golder Associates Inc. 44 Union Boulevard, Suite 300 Lakewood, CO 80228 Prepared For: Waste Management Disposal Services of Colorado, Inc. North Weld Landfill 40000 Weld County Road 25 Ault, CO 80610 December 21, 2016 1538880 Golder Associates Golder, Golder Associates and the GA globe design are trademarks of Golder Associates Corporation December 2016 1538880 Table of Contents 1.0 INTRODUCTION 1 1.1 Project Background 1 1.2 Scope 1 1.3 Construction Schedules 2 1.4 Document Format 2 2.0 PROJECT PERSONNEL AND CONTACTS 3 2.1 WMDSC Personnel 3 2.2 Design Engineer 3 2.3 Certifying Engineer (CQA Engineer) 3 2.4 CQA Laboratory 3 2.5 Site Surveyor 3 2.6 Construction Contractor 3 2.7 Geomembrane Liner Contractor 4 2.8 Colorado Department of Health and Environment (CDPHE) 4 2.9 Weld County Department of Public Health and Environment (WCDPHE) 4 3.0 CONSTRUCTION MEETINGS 5 3.1 Preconstruction Meeting 5 3.2 Project Progress Meetings 5 4.0 DOCUMENTATION 7 4.1 Standard Reporting Procedures 7 4.2 Applicable Forms 7 4.3 Agency Notification 8 4.4 Issue Identification and Corrective Action 8 4.5 Photographic Documentation 8 4.6 Site Survey Requirements 8 4.6.1 Record Surveys 8 4.6.2 Survey Tolerances 10 4.7 Calibrating Testing Equipment 10 4.8 Complying with Test Standards 10 5.0 LANDFILL CQA—EARTHWORK 11 5.1 Subgrade Preparation 11 5.1.1 Construction Requirements 11 5.1.2 CQA Testing 11 5.1.3 CQA Sampling 11 5.1.4 Leachate Collection Drain Line CQA 12 5.2 Compacted Cohesive Soil Liner 12 5.2.1 Construction Requirements 12 1:115\1538880\040010404 edop fnl decl6tiappendix e_cqa plantiapp e nwlf cqa plan 21dec16.docx Golder Associates December 2016 ii 1538880 5.2.2 CQA Testing 13 5.2.3 CQA Sampling 15 5.3 Inter -phase and Inter -module Separation Berms 15 5.4 Protective Layer 15 5.5 Alternative Final Cover 16 5.5.1 Construction Requirements 16 5.5.2 CQA Testing 16 5.5.3 CQA Sampling 16 6.0 CQA► — LEACHATE COLLECTION SYSTEM 18 6.1 Geotextile Fabric 18 6.2 Leachate Drain and Sump Gravel 18 6.3 Granular Drainage Layer 19 6.4 Leachate Collection Sumps (Permanent and Temporary) 19 7.0 CQA — GEOMEMBRANE LINER 21 7.1 CQA Functions 21 7.2 Pre -construction Submittal Review 21 7.3 Material Specifications, Handling, and Storage 21 7.4 Geomembrane Support 22 7.5 Deployment 22 7.5.1 Weather Conditions 22 7.5.2 Documentation of Panel Placement 23 7.5.3 Method of Deployment 23 7.5.4 General Seaming/Welding Procedures 23 7.5.5 Extrusion Fillet welding 24 7.5.6 Seaming Documentation 24 7.5.7 Trial welds 24 7.5.8 Testing 25 7.6 Repairs 26 8.0 FINAL CONSTRUCTION DOCUMENTATION REPORT 27 List of Tables Table 1 Table 2 Table 3 Soil Construction Quality Assurance Testing and Frequencies Geomembrane Construction Quality Assurance Testing and Frequencies Seed Mix and Soil Amendments i:115\153888th040010404 edop fnl decl6tiappendix e_cqa plantiapp e nwlf cilia plan 21dec16.docx Golder Associates December 2016 1 1538880 1.0 INTRODUCTION 1.1 Project Background The North Weld Landfill (NWLF) is located in Weld County, Colorado and is owned and operated by Waste Management Disposal Services of Colorado, Inc. (WMDSC). The NWLF site occupies approximately 358 acres. A Certificate of Designation (CD) from the Weld County Board of Commissioners was first issued on June 27, 1990, for Unit 1, which encompassed approximately 122 acres of disposal area. The site first received waste on February 3, 1992. An application for a CD for Unit 2, which will add approximately 155 acres of disposal area, will be submitted to Weld County in 2016. This Construction Quality Assurance Plan (CQA Plan) outlines the monitoring, testing, and documentation requirements for liner and final cover construction at NWLF. CQA personnel shall use this CQA Plan as the guidance document to implement the CQA program for all future liner and final cover construction work and is intended to eliminate the need for preparation of separate CQA Plans for each construction project. This CQA Plan addresses quality assurance, not quality control. This CQA Plan provides the plan for independent third -party CQA verification and testing. Construction quality control (CQC) is independently provided by manufacturers and contractors and refers only to those actions taken by them to ensure that materials and workmanship meet the requirements of the design. 1.2 Scope Construction activities associated with liner construction at NWLF may include: • Excavation and stockpiling of soil from within the project area; • Excavation and grading for appropriate drainage control and stormwater control features; • Installation of a two -foot -thick compacted cohesive soil liner; • Installation of a leachate collection system consisting of gravel drain lines; • Installation of a drainage layer over the compacted cohesive soil liner and leachate collection system and a six -inch -thick protective layer over the liner side slopes; • Construction of temporary and/or permanent leachate collection sumps, including the installation of geomembrane liner below the permanent sumps; and • Installation of inter -phase and/or inter -module separation berms over the liner system. Construction activities associated with final cover construction at NWLF may include: • Installation of a 30 -inch -thick water balance alternative final cover (AFC); and • Seeding of the AFC cover. i:15\1538880\040010404 edop fnl decl6tiappendix e_cqa planlapp e nwlf cqa plan 21dec16.docx Golder Associates December 2016 2 1538880 1.3 Construction Schedules Construction schedules shall be prepared prior to each construction project and updated as necessary during construction. 1.4 Document Format This CQA Plan is organized as follows: ■ Section 1 provides this introduction and defines the scope of the document. ■ Section 2 defines personnel and organizations that will be involved with CQA and their roles. ■ Section 3 provides information regarding various CQA-related meetings. ■ Section 4 defines general CQA documentation procedures, including items such as project reporting, data collection, record keeping, and site surveying requirements. ■ Section 5 defines CQA procedures for earthwork construction. ■ Section 6 defines CQA procedures for leachate collection system construction. ■ Section 7 defines CQA procedures for geomembrane manufacturing and installation. ■ Section 8 defines requirements for the Construction Documentation Report. i:115\153888th040010404 edop fnl decl6tiappendix e_cga plantiapp e nwlf cqa plan 21dec16.docx Golder Associates December 2016 3 1538880 2.0 PROJECT PERSONNEL AND CONTACTS 2.1 WMDSC Personnel Key WMDSC personnel for construction projects at NWLF will include the district manager and project manager. 2.2 Design Engineer The design engineer is the individual or firm that is responsible for the design as it exists at the time construction begins and the preparation of the construction drawings for the project. Construction drawings are defined as the part of the contract documents that graphically show the scope, extent, character, and details of the work to be performed. The design engineer may be a WMDSC representative or a consulting engineering firm contracted by WMDSC to prepare the construction drawings. Contact information for the design engineer shall be provided to appropriate parties prior to the construction. 2.3 Certifying Engineer (CQA Engineer) The certifying engineer (CQA engineer) is the individual or firm that, on behalf of WMDSC, is responsible for monitoring construction activities on site and certifying that the work is constructed in accordance with the contract documents, including this CQA Plan. A certifying engineer shall be chosen by WMDSC prior to each construction project. 2.4 CQA Laboratory A CQA soils laboratory► shall be selected by the certifying engineer or by WMDSC prior to each construction project to perform quality assurance (QA) testing on soil samples to verify that the work is constructed in accordance with the contract documents, including this CQA Plan. 2.5 Site Surveyor A site surveyor shall be chosen by WMDSC or subcontracted by the contractor for eachconstruction project to certify that as -built conditions conform to the design specified in the contract documents. 2.6 Construction Contractor A general construction contractor shall be chosen by WMDSC for each construction project and shall be contracted directly by WMDSC. Work conducted by the contractor shall be overseen and certified by the certifying engineer. i:115\153888th040010404 edop fnl decl6tiappendix e_cqa planlapp e nwlf cqa plan 21dec16.docx Golder Associates December 2016 4 1538880 2.7 Geomembrane Liner Contractor A liner contractor shall be selected to install geomembrane in the sump areas. The liner contractor may be the general contractor, a subcontractor to the contractor, or independently► contracted by WMDSC. Work conducted by the liner contractor shall be overseen by the certifying engineer. 2.8 Colorado Department of Health and Environment (CDPHE) Construction documentation reports certifying that the construction work was constructed in accordance with the contract documents, including this CQA Plan, shall be submitted to the Colorado Department of Health and Environment (CDPHE) Hazardous Materials and Waste Management Division, Solid Waste Unit at the following address: Colorado Department of Public Health & Environment Solid Waste Unit Hazardous Materials & Waste Management Division 4300 Cherry Creek Drive South Denver, Colorado 80246 2.9 Weld County Department of Public Health and Environment (WCDPHE) Construction documentation reports shall also be submitted to the Weld County Department of Public Health and Environment at the following address: Weld County, Department of Public Health and Environment 1555 N. 17th Avenue Greeley, Colorado 80631 i:115\153888th040010404 edop fnl decl6tiappendix e_cqa plantiapp e nwlf cqa plan 21dec16.docx Golder Associates December 2016 5 1538880 3.0 CONSTRUCTION MEETINGS 3.1 Preconstruction Meeting Prior to the start of construction, a preconstruction meeting shall be held involving the general contractor, liner contractor (if applicable), district manager, project manager, site surveyor, and certifying CQA engineer. The preconstruction meeting agenda shall identify party responsibilities, construction documents, lines of communication, design and CQA Plan requirements, construction schedule requirements and/or limitations, and Health and Safety Environment Plan (HaSEP) requirements. The purpose of the meeting shall be to: ■ Present a proposed construction progress schedule and submittal log as required by the contract documents ■ Discuss procedures for handling submittals ■ Discuss the rules for project correspondence and roles and responsibilities ■ Establish reporting and documentation procedures for each party ■ Schedule weekly progress meetings ■ Present a summary of the laboratory testing and field testing required to meet COO and CQA requirements ■ Discuss procedures for field orders, work change directives, and change orders ■ Discuss the WMDSC's DSC's site rules ■ Review the contract documents ■ Review the CQA Plan ■ Review work area security, safety procedures, and related issues ■ Provide all parties with relevant contract documents ■ Review testing equipment and procedures ■ Establish testing protocols and procedures for correcting and documenting non -conforming work or materials ■ Conduct a site inspection to discuss the work area, stockpile areas, lay -down areas, material storage areas, access roads, haul roads, and related items The minutes from the meeting shall be included as an appendix to the Construction Documentation Report. 3.2 Project Progress Meetings Generally, project progress meetings shall be conducted on a weekly basis with the contractor, liner contractor (if applicable), certifying CQA engineer, district manager, project manager, and site surveyor (as necessary). These meetings shall include the following: ■ Discussion of health and safety issues relevant to scheduled work ■ Work in progress and key activities scheduled for the upcoming week i:115\153888th040010404 edop fnl decl6tiappendix e_cqa pla&app e nwlf cilia plan 21dec16.docx Golder Associates December 2016 6 1538880 ■ Updates to the overall construction schedule ■ Review of relevant CQA test data ■ Discussion of any necessary decisions or project requirements regarding the construction activities. ■ Resolution of outstanding issues or disputes If necessary, a brief daily meeting with the above parties shall be conducted to address any critical construction matters and determine an acceptable course of action. The certifying engineer shall maintain a file containing notes from such meetings and a copy of the notes shall be provided to the project manager. i*15ti153888th040010404 edop fnl dec16\appendix e_cqa plantiapp e nwlf cqa plan 21dec16.docx Golder Associates December 2016 7 1538880 4.0 DOCUMENTATION The success of the CQA program requires thorough performance of the specified monitoring and testing activities, documentation of completed monitoring and testing activities, and frequent senior review of CQA documentation. Therefore, the certifying engineer must help assure that all CQA procedures have been implemented, results of the program are reviewed frequently, and corrections are implemented as needed. 4.1 Standard Reporting Procedures The CQA engineer shall issue a daily report of construction activities. These reports shall contain, at a minimum and as applicable, the following information: 1. Date, project name, location, weather, and other information as appropriate 2. Description and locations of ongoing construction 3. Equipment used 4. Description of areas tested and sampled 5. Description of areas requiring reconditioning, retesting, and procedures followed 6. Summar)/ of compacted cohesive soil liner lift thickness and cohesive soil moisture —density at time of placement, as applicable 7. Summary of leachate collection system and sump construction, as applicable 8. Surveys performed for lift thickness control and any record surveys performed 9. Description of any variations from the contract documents and justification for the variance 4.2 Applicable Forms The forms to be used in documenting the daily activities shall generally consist of the following: 1. Daily Field Report 2. Request for Information 3. Field Density Test Forms 4. Soil Sample Test Request Forms 5. Soil Testing Tracking Log 6. Geomembrane Testing, Deployment, Seaming, Defect, and Repair Logs Prior to the pre construction meeting, the certifying engineer shall provide the project manager with samples of these forms for review and approval. All completed daily recordkeeping forms shall be checked, reviewed, signed, and dated by the certifying engineering on a weekly basis. Completed daily field report forms shall be bound separate from the Construction Documentation Report and copies shall be kept at NWLF. Applicable field data sheets and i:115\153888th040010404 edop fnl decl6tiappendix a cqa ptanfiapp e nwlf eqa plan 2ldecl6.docx Golder Associates December 2016 8 1538880 recordkeeping forms shall also be included as appendices to the Construction Documentation Report as further described in Section 8.0 of this CQA Plan. 4.3 Agency Notification All contact with the CDPHE and the WCDPHE shall be the responsibility of and conducted by the project manager or a project manager -designated representative. 4.4 Issue Identification and Corrective Action The certifying engineer shall inform the contractor and/or liner contractor in a timely manner of any difference between the contractor's and/or liner contractor's interpretation of the contract documents and the certifying engineer's interpretation. In addition, any actual or suspected work deficiencies shall be promptly brought to the attention of the project manager. If a difference in interpretation cannot readily be resolved between the contractor and certifying engineer, a meeting shall be held involving the district manager, project manager, contractor, and certifying engineer. The objective of the meeting shall be to define and discuss the issue, review alternative solutions, and implement an action plan to resolve the issue to the satisfaction of all parties. If the issue involves a possible design modification, the design engineer shall be contacted for approval. If a field modification is required that affects the Engineering Design and Operations Plan (EDOP) or regulatory requirement, the CDPHE and, if necessary, the WCDPHE, shall be contacted for approval and to identify the documentation that is required. Applicable documentation shall be included as an appendix to the Construction Documentation Report. 4.5 Photographic Documentation Photographs (indicating date) shall be taken to document observations and as -built conditions of elements of construction. These photos shall be labeled to identify, at a minimum, date, location where photo was taken, direction of photo, and a brief description of the photo. The photographs shall be compiled in chronological order and captioned by the certifying engineer in a photograph log. Copies of the photograph log shall be kept at NWLF. 4.6 Site Survey Requirements 4.6.1 Record Surveys Site survey requirements shall include performing record surveys. At a minimum, record surveys shall be performed on the subgrade, compacted cohesive soil liner, leachate collection drain line and drainage layer, and bottom and top elevations of sumps. Record surveys shall confirm that the work was constructed in i:115\153888th040010404 edop fnl decl6tiappendix e_cqa planlapp e nwlf cilia plan 21dec16.docx Golder Associates December 2016 9 1538880 accordance with the contract documents. Record surveys to be performed by the site surveyor shall include the following, as applicable to the construction project: 1. Subgrade record survey: a. Subgrade on a 50 -foot x 50 -foot grid, inclusive of sumps. b. All subgrade breaklines on 50 -foot centers, inclusive of the leachate collection drain line alignment. c. Edge of the subgrade/compacted cohesive soil liner interface for existing liner on 50 -foot centers. 2. Top of compacted cohesive soil liner: a. 50 -foot x 50 -foot grid, inclusive of sumps. The certification grid shall be the same grid used for the certification of the subgrade on the floor. b. All breaklines, as appropriate, and edges on 50 -foot centers. c. Top of edge where liners are tied together on 50 -foot centers. d. Location where geomembrane liner is anchored in compacted cohesive soil liner on 50 -foot centers. 3. Leachate collection drain line and permanent/temporary sumps: a. Subgrade at 50 -foot intervals along the leachate collection drain line. b. Top of compacted cohesive soil liner along the leachate collection drain line at 50 -foot intervals. c. Survey stationing shall be at the same horizontal locations as the 50 -foot grid used for certification of subgrade and top of compacted cohesive soil liner. Each survey point along the 50 -foot stationing shall have three associated elevations: subgrade, top of compacted cohesive soil liner, and top of gravel drain line. d. Top of leachate collection drain line at tie-in points and end of line. e. Grade breaks and corners for subgrade and top of compacted cohesive soil liner in sumps. 4. Finished grades: a. Top of drainage layer on 100 -foot x 100 -foot grid. The grid shall be the same grid used for certification of subgrade and top of compacted cohesive soil liner on the floor. Thickness may be verified using a calibrated probe or by survey. b. All breaklines and mid -slope points of protective layer on 50 -foot centers. c. Thicknesses shall be summarized in a plan view figure identifying grid points and in a table presenting thickness measurements to be included in the Construction Documentation Report. All survey data shall be reduced at the end of each working day, or other frequency appropriate for the survey work performed, and given to the certifying engineer in the form of a report. Record surveys and record grade tables shall be included in an appendix to the Construction Documentation Report to document that the work was performed in accordance with the construction documents. i:115\153888th040010404 edop fnl decl6tiappendix e_cqa pla&app e nwlf cilia plan 21dec16.docx Golder Associates December 2016 10 1538880 4.6.2 Survey Tolerances Construction tolerances for excavation and fill shall consist of the following: 1. Top of Subgrade Line: ±0.5 foot Grade: -0.2 to 0.0 feet 2. Compacted cohesive soil liner: Line: ±0.5 feet Grade: -0.0 to +Q.1 feet of top of liner design grade Thickness: 2.0 feet (minimum) 3. Protective layer: Line: ±0.5 feet Grade: -0.0 to +0.2 feet of top of protective layer design grade Thickness: 2.5 to 2.8 feet combined thickness of compacted cohesive soil liner and protective layer measured perpendicular to slope 4. Drainage layer: Thickness: 0.5 feet (minimum) 5. Gravel drain lines Line: ±0.5 foot Grade: -0.0 to +0.1 foot Thickness: 1.0 foot (minimum) 6. Sumps 7. Final Cover Line: ±0.5 foot Grade: -0.2 to +0.1 feet The final cover line and grade may vary due to landfill settlement. Construction documentation will demonstrate conformance with the minimum cover thickness and mini um/maximum final design slopes. 4.7 Calibrating Testing Equipment Before on -site testing equipment is placed into service, the accuracy of each piece of equipment shall be verified by calibration. Types of on -site equipment requiring calibration include nuclear gauges (calibration and daily standardization), tensiometers, scales, and field ovens. The calibration procedures and frequencies shall be completed per the equipment manufacturer's instructions and American Society for Testing and Materials (ASTM) standards as applicable. Copies of current calibration certificates for equipment shall be maintained by the CQA engineer and dates of last calibration for all field and laboratory testing equipment shall be provided in the Construction Documentation Report. Whenever a piece of equipment is suspected of producing questionable results, it shall be removed from service and re -calibrated. 4.8 Complying with Test Standards The CQA laboratory and CQA engineer must perform various field and laboratory tests in accordance with applicable standards as specified in this CQA Plan. In most instances, the applicable test procedure is an ASTM standard. Only the most recent version of each test standard identified in this CQA Plan shall be used. i*15ti153888th040010404 edop fnl decl6tiappendix e_cga plantiapp e nwlf cqa plan 21dec16.docx Golder Associates December 2016 11 1538880 5.0 LANDFILL CQA EARTHWORK 5.1 Subgrade Preparation 5.1.1 Construction Requirements The liner subgrade shall be established by excavating overburden soils to the design grades as shown in the construction drawings. In some areas, engineered fill may be required to develop the design grades. Upon attainment of subgrade grades by excavation and compaction, the CQA engineer shall observe the subgrade conditions and document any unexpected conditions, such as wet or unstable areas, permeable lenses, or other condition not be suitable for liner foundation as determined by CQA engineer. Any unstable area, permeable lens, or other unsuitable condition shall be excavated at least one foot in depth and replaced with engineered fill material. Engineered fill shall be placed in compacted lifts not exceeding 12 inches. Engineered fill shall be compacted to a minimum density of 95% of the standard Proctor maximum dry density (ASTM D698). 5.1.2 CQA Testing Subgrade material and construction shall conform to the following specifications: • Grade control: as described in Sections 4.6.1 and 4.6.2 of this CQA Plan • Compaction (ASTM D6938) greater than or equal to 95% of standard Proctor • (Engineered Fill only) maximum dry density (ASTM D698) In situ density testing (ASTM D6938) of engineered fill shall be performed on an approximate grid pattern randomly defined by the CQA engineer for each 12 -inch lift placed. 5.1.3 CQA Sampling Representative samples of the native subgrade and engineered fill materials shall be obtained prior to and during subgrade preparation for the following laboratory testing: • Grain size (no hydrometer) (ASTM D6913) • Moisture content (ASTM D2216 or ASTM D4643) • Standard Proctor (5 points per curve) (ASTM D698) In the event that the engineered fill material changes, additional samples shall be collected and tested for each material type to define standard Proctor maximum dry density and optimum moisture content. Sampling and testing frequencies for subgrade preparation and engineered fill placement are provided in Table 1 of this CQA Plan. All field and laboratory testing results shall be provided as an appendix to the Construction Documentation Report. The certifying engineer shall reference all test and sample points and reconstructed areas by measuring from reference points established for the on -site coordinate system. i:115\153888th040010404 edop fnl decl6tiappendix e_cqa pla&app e nwlf cilia plan 21dec16.docx Golder Associates December 2016 12 1538880 ,5.1.4 Leachate Collection Drain Line CQA While constructing the subgrade, the chevron pattern shall be graded to form the leachate collection drain line alignment. A►s discussed in Section 4.6.1 of this CQA Plan, the site surveyor shall perform record survey documentation of the subgrade, top of compacted cohesive soil liner, and top of gravel drain line along the leachate collection drain line alignment. Field density testing of the subgrade along the leachate collection drain line shall be in accordance with the requirements of Section 5.1.2 of this CQA Plan. 5.2 Compacted Cohesive Soil Liner £2.1 Construction Requirements The compacted cohesive soil liner shall be constructed in accordance with design criteria presented in the NWLF Unit 2 EDOP (briefly summarized below) and as described in the contract documents. ■ Base grades will be consistent with approved design grades. ■ The minimum thickness of the compacted cohesive soil liner at all locations shall be two feet measured perpendicular to the liner surface. ■ The compacted cohesive soil liner shall be constructed in lift heights no greater than six inches after compaction (eight inches loose) and no greater than the depth of the teeth of the compaction equipment used. ■ Typical side slopes shall not exceed three horizontal to one vertical (3H :1 V), unless otherwise shown in the construction drawings. The compacted cohesive soil liner material shall have a maximum allowable clod size of three inches. A pull -type disc (or similarly effective equipment as approved by CQA engineer) shall be used to break up clods, expose stones in the cohesive soil to allow for removal, and assist in establishing moisture content above optimum as determined by standard Proctor moisture —density testing (ASTM D698). The specification for acceptable moisture content range is described below in Section 5.2.2 of this CQA Plan. Compaction shall be performed using a tamping foot compactor with fully penetrating feet extending the full depth of the loose lift of soil (Caterpillar 815, 825, or CQA engineer -approved alternate equipment). Compaction may be supplemented by running wheeled tracks of construction equipment across fill areas; however, the use of supplementary vehicular tracking shall not be used in place of mechanical compaction with the tamping foot compactor. The number of tamping foot compactor passes required to achieve the required compaction shall be determined during the first lift of compacted cohesive soil liner placement, and monitored throughout subsequent lifts. Compaction shall be performed to form a stable non -yielding base. Frozen materials, organics, roots, and large rocks (greater than three inches in any dimension based on visual observation) shall be removed prior to compaction. i*15ti153888th040010404 edop fnl decl6tiappendix e_cga pla&app e nwlf cqa plan 21dec16.docx Golder Associates December 2016 13 1538880 Prior to placing compacted cohesive soil liner on side slopes, the subgrade shall be scarified (if lifts are placed horizontally) or proof -rolled with a tamping foot compactor (if lifts are placed parallel to the slope). The surface of previous lifts shall be watered as necessary until subsequent lifts or cover materials are placed to prevent desiccation. The contractor shall not be allowed to place cohesive soil at temperatures below freezing unless it can be demonstrated that freezing of the compacted cohesive soil liner will not occur. Previously placed soils shall be protected from freezing by the contractor by methods such as placing additional soil over the completed compacted cohesive soil liner until protective cover is placed. Any placed liner material that is found to be frozen shall be removed or thawed and reworked as necessary. Tie-in to compacted cohesive soil liner of previously constructed cells (where applicable) shall be performed by constructing "steps" in the formerly placed liner. The "steps" shall be approximately six inches in depth and at least six inches wide, shall be cut with an excavator or other appropriate equipment, and shall extend the full depth of the previously placed compacted cohesive soil liner. After the "steps" are cut, placement of the new compacted cohesive soil liner shall begin by placing in lifts that correspond to the thickness of the "steps." Each lift shall be compacted through the step area so that there are no vertical seams in the former "step" area. Once this is complete, the next lift shall be placed and the procedure repeated until the entire thickness of compacted cohesive soil liner has been placed through the tie-in area. 52.2 CQA Testing Compacted cohesive soil liner material and construction shall conform to the following specifications: • Grade control: As described in Sections 4.6.1 and 4.6.2 of this CQA Plan • Classification (ASTM D2487): CL or CH under the Unified Soil Classification System • Hydraulic conductivity (ASTM D5084): Less than or equal to 1 x 10► -7 cm/sec • Density (ASTM D3668): Greater than or equal to 95% of standard Proctor maximum dry density (ASTM D698) • Moisture content (ASTM D6938, ASTM D2216, or D4643): 80% of tests exceeding required degree of saturation and a minimum degree of saturation of 75% for all tests • Liquid limit (ASTM D4318): Greater than 25% • Plasticity index (ASTM D4318): Greater than 10% • Grain size (ASTM D6913): P200 content of 50% or greater by weight In -place moisture content and density testing (ASTM D6938) of the compacted cohesive soil liner shall be performed randomly but on a density equivalent to a 100 -foot grid pattern for each 6 -inch compacted lift placed to ensure that the testing locations and samples collected for hydraulic conductivity are evenly distributed with a comparable number of tests for each lift. The testing grid pattern shall be offset on subsequent lifts. For side slopes, minimum testing requirements shall be determined based on the surface area of the slopes. i:115\1538880\040010404 edop fnl dec16\appendix e_cqa plantiapp e nwlf cqa plan 21dec16.docx Golder Associates December 2016 14 1538880 Additional moisture and density tests shall be obtained in confined areas where equipment movement is hindered or hand compaction is necessary. The number of density tests in these areas shall be specified by the CQA engineer based on the size of the confined area. If areas are encountered which do not meet the specified compaction, moisture content, or percent saturation the area shall be reworked, moisture conditioned, and/or recompacted as necessary. Retests shall be performed following rework activities. At least 80% of all field moisture and density tests (and within two -acre subareas) shall have a degree of saturation on or wet of the degree of saturation line corresponding to the applicable standard Proctor test optimum moisture content and maximum dry density, which is defined as the line or curve corresponding to the degree of saturation that goes through the optimum moisture content/maximum dry density point. The degree of saturation defining the line is calculated using the following equation: (w)(G5) ( 100 ) _ (Gs) (yw 1) x100% I' Id where: = Degree of saturation (%) W = In situ moisture content from field test (%) Gs = Specific gravity yw Unit weight of water (62.4 pcf) yd = Dry unit weight of soil (pcf) The minimum degree of saturation shall be 75%. Degree of saturation shall be calculated from standard Proctor optimum moisture content and maximum dry density unless evidence demonstrates that the compactive energy being used is higher than that corresponding to the standard Proctor (i.e., moisture content/density tests that are plotting at significantly higher dry densities). In this case, the degree of saturation corresponding to the optimum moisture content/maximum dry density of the modified Proctor or an average of standard Proctor and modified Proctor can be used at the CQA engineer's discretion. Plan view figures identifying the locations of field density measurements and the two -acre subareas for each lift shall be prepared and included in the Construction Documentation Report. If areas with compaction of less than 95% of the standard Proctor maximum dry density or required degree of saturation are encountered, the area shall be reworked to provide additional moisture conditioning or additional compactive effort. Retests shall be performed following the reworking activities. Each penetration made into the compacted cohesive soil liner for density testing purposes shall be repaired after testing. The test hole shall be repaired by backfilling with bentonite and hydrated or other material(s) approved by the CQA engineer. i*15ti153888th040010404 edop fnl decl6tiappendix e_cga pla&app e nwlf cqa plan 21dec16.docx Golder Associates December 2016 15 1538880 All density tests shall be reported on the field density forms. Test locations shall be presented on a plan view figure. Completed field density forms shall be included as an appendix to the Construction Documentation Report. Prior to the preconstruction meeting, the CQA engineer shall provide the project manager with a sample of the field density form for review and approval. 5. .3 CQA Sampling Representative samples of compacted cohesive soil liner material shall be obtained prior to and during liner construction for the following laboratory testing: 1. Soil classification (ASTM D2487) 2. Grain size (no hydrometer) (ASTM D6913) 1. Atterberg limits (ASTM D4318) 2. Moisture content (ASTM D2216 or ASTM D4643) 3. Standard Proctor (five points per curve) (ASTM D698) 4. Modified Proctor (ASTM D1557) 5. Hydraulic conductivity (ASTM D5084) 6. Specific gravity (ASTM D854) 7. One -point Proctors (conducted in the field) (AASHTO T272) Sampling and testing frequencies for the compacted cohesive soil liner are provided in Table 1 of this CQA Plan. One -point Proctors shall be performed at the specified frequency to assist the certifying engineer in the selection of the appropriate standard Proctor for the purposes of evaluating passing moisture content and density conditions. A soil sample inventory log shall be maintained as samples are acquired. The certifying engineer shall reference all test and sample points and reconstructed areas by measuring from reference points established for the on -site coordinate system. All completed inventory logs and field and laboratory testing results shall be provided as an appendix to the Construction Documentation Report. 5.3 Inter -phase and Inter -module Separation Berms Compacted engineered fill material shall be used to construct inter -phase and inter -module berms. Moisture conditioning shall be performed as necessary and/or as directed by the CQA engineer. 5.4 Protective Layer A six-inch soil protective layer shall be placed over the compacted cohesive soil liner side slopes. The protective layer material shall consist of compacted cohesive soil liner material or random material as defined in the contract documents. The protective layer shall be placed in successive lifts of not more than eight inches in loose depth. Compaction operations shall consist of at least three passes with suitable equipment or otherwise approved by the CQA engineer. The CQA engineer shall observe and report on appropriate CQA test results and placement operations to verify uniform lift thickness and adequate compaction. i:115\1538880\040010404 edop fnl dec16\appendix e_cqa pla&app e nwlf cqa plan 21dec16.docx Golder Associates December 2016 16 1538880 5.5 Alternative Final Cover 5.53 Construction Requirements The water balance alternative final cover (AFC) soil shall be placed without active compaction so as to obtain a density of between 80% and 90% of the standard Proctor (ASTM D698) maximum dry density and dry of the optimum moisture content. After placement, the AFC shall be fertilized if necessary and planted with erosion -controlling grasses native to the region, such as the seed mix provided in Table 3 of this CQA Plan. Soil amendment recommendations are also provided in Table 3. 5.5.2 CQA Testing AFC material and construction shall conform to the following specifications: ■ Grade control: verification of foundation grades and slopes prior to AFC construction. Thickness of AFC layers on 100 -foot x 100 -foot grid, by grade stakes or survey. ■ Grain Size (ASTM D6913): gravel content 15% or less by weight. ■ Maximum particle size less than two inches. ■ Moisture content (ASTM D6938 and ASTM D2216 or D4643): dry of the optimum moisture content. ■ Moisture -density (ASTM D698): between 80% and 90% of standard Proctor maximum dry density. ■ pH (SW -846 SW 9045C): 6.0 — 8.4. ■ Calcium carbonate (CaCO3) (USDA Handbook Number 60): less than 15% by weight. In -place moisture content and density testing (ASTM D6938) of the AFC portion of the final cover shall be performed at a frequency of 1 test per 6,500 cubic yards of final cover placed. If areas are encountered which do not meet the specified compaction or moisture content requirements, the area shall be reworked or ripped as necessary. Retests shall be performed following rework activities. 5.5.3 CQA Sampling Representative samples of AFC material shall be obtained during final cover construction for the following laboratory testing: 1. Grain size (ASTM D422) 2. Hydrometer (ASTM D7928) 3. Moisture content (ASTM D2216 or D4346) 4. Standard Proctor (five points per curve) (ASTM D698) 5. pH (SW -846 SW 9045C) 6. CaCO3 (USDA Handbook Number 60) i:\15\15388801040010404 edop fnl dec16\appendix e_cga pla&app e nwlf cilia plan 21dec16.docx Golder Associates December 2016 17 1538880 Sampling and testing frequencies for final cover are provided in Table 1 of this CQA Plan consistent with the CDPHE Final Guidance Document for Water Balance Covers in Colorado (CDPHE 2013). The certifying engineer shall reference all test and sample points and reconstructed areas by measuring from reference points established for the on -site coordinate system. All field and laboratory testing results shall be provided as an appendix to the Construction Documentation Report. i:15\1538880\040010404 edop fnl decl6tiappendix a cqa plantapp e nwlf cqa plan 21dec16.docx Golder Associates December 2016 18 1538880 6.0 CQA - LEACHATE COLLECTION SYSTEM Leachate collection system construction shall follow completion of the compacted cohesive soil liner in the areas of the sumps and leachate collection gravel drain lines. Construction shall consist of the placement of geomembrane (in permanent sumps), geotextile fabric, leachate drain and sump gravel, and granular drainage layer (granular earthen material or glass Gullet) material as discussed in this section. 6.1 Geotextile Fabric Geotextile fabric used to wrap the leachate collection trenches shall be non -woven, 10 -ounce per square yard (oz/sq. yd.) geotextile. Placement shall conform to the following requirements: 1. Fabric shall be placed as smooth and wrinkle -free as possible without "stretching." 2. The gravel drain lines shall be wrapped in geotextile fabric as shown in the construction drawings. 3. Geotextile fabric shall overlap at all seams by a minimum of 24 inches. CQA requirements for the geotextile fabric consist of the following: 1. Geotextile fabric shall be free of tears, holes, other visible damage, and significant folds or wrinkles. 2. Geotextile fabric quality control (CQ) certificates shall be included as an appendix to the Construction Documentation Report. 6.2 Leachate Drain and Sump Gravel The leachate drain and sump gravel shall consist of rounded, semi -angular or angular clean gravel or other permeable material that meets the following requirements: ■ Grade control: • As described in Sections 4.6.1 and 4.6.2 of this CQA Plan. ■ Classification (ASTM D2487): • Earthen material (i.e., not glass Gullet) classified as GP. ■ Grain size (ASTM C136): • A minimum of 99% passing the three-inch sieve by weight; • Between 0 and 5% passing the 3/8 -inch sieve by weight; and • d50 of less than 1.5 inch. (The material gradation may vary provided that testing confirms the material meets the permeability requirement) ■ Hydraulic conductivity (ASTM D5084): Greater than or equal to 1 cm/sec ■ Thickness: A minimum of 12 inches of aggregate material shall be placed within each geotextile-wrapped gravel drain measured perpendicular to the slope. The aggregate height shall be documented with a field survey or hand measurements. i:115\153888M040010404 edop fnl decl6tiappendix e_cga pla&app e nwlf cilia plan 21dec16.docx Golder Associates December 2016 19 1538880 Representative samples of drainage gravel material shall be obtained prior to and during leach ate collection system construction for the following laboratory► testing: 1. Grain size (no hydrometer) (ASTM 0136) 2. Hydraulic conductivity (ASTM D5084) Sampling and testing frequencies for drainage gravel are provided in Table 1 of this CQA Plan. Laboratory testing results shall be provided as an appendix to the Construction Documentation Report. 6.3 Granular Drainage Layer The granular drainage layer shall consist of a minimum of 6 inches of sand or 8.5 inches of glass cullet placed over the compacted cohesive soil liner. The granular drainage layer requirements are as follows: ■ Grade control: as described in Sections 4.6.1 and 4.6.2 of this CQA Plan. ■ Hydraulic conductivity (ASTM D5084): greater than or equal to 1 x 16-2 cmisec. Representative samples of granular drainage layer material shall be obtained prior to and during cell construction for the following laboratory testing: ■ Hydraulic conductivity (ASTM D5084) Sampling and testing frequencies for granular drainage layer material are provided in Table 1 of this CQA Plan. Laboratory testing results shall be provided as an appendix to the Construction Documentation Report. 6.4 Leachate Collection Sumps (Permanent and Temporary) Permanent leachate collection sumps shall be constructed at the low point in each disposal phase (Phases 4 and 5). Temporary leachate collection sumps shall be installed at the low point of each module within disposal phases. Two feet of compacted cohesive soil liner shall be maintained beneath all portions of the leachate collection system, including leachate collection sumps. Compacted cohesive soil liner material shall be placed and compacted as described in Section 5.2 of this CQA Plan in the leachate collection sump areas prior to additional sump construction. At least five in -place density tests shall be taken per six-inch lift within the base and on each sidewall of the sump. Additionally, a minimum of one in -place density test shall be performed on the compacted cohesive soil located in the geoembrane anchor trench surrounding the permanent sump after geomembrane installation (see Section 7.0 of this CQA Plan for geomembrane CQA requirements). Gravel material, as described in Section 6.2 of this CQA Plan, shall be used to backfill leachate collection sumps. The same sampling and testing frequencies for drainage gravel as discussed in Section 6.2 and i*15ti153888th040010404 edop fnl decl6tiappendix e_cga pla&app e nwlf cqa plan 21dec16.docx Golder Associates December 2016 20 1538880 provided in Table 1 of this CQA Plan shall apply► to the leachate collection sumps. Laboratory► testing results shall be provided as an appendix to the Construction Documentation Report. In addition, survey control of the sumps shall be documented as discussed in Sections 4.6.1 and 4.6.2 of this CQA Plan. The CQA requirements for geomembrane liner in permanent sump areas is described in Section 7.0 of this CQA Plan. i:115\153888th040010404 edop fnl decl6tiappendix e_cqa plantiapp e nwlf cqa plan 21dec16.docx Golder Associates December 2016 21 1538880 7.0 CQA-GEOMEMBRAHE LINER 7.1 CQA Functions Prior to geomembrane installation, the CQA engineer shall observe the on -site liner storage area and handling of the liner packaging to detect possible damage. During placement, the CQA engineer shall observe the seam overlap, seam preparation, welding, seam testing, and correction of deficiencies. The CQA engineer shall document the sampling conducted, sampling results, locations of destructive samples, locations of patches, locations of seams and any problems encountered during geomembrane placement and include as an appendix to the Construction Documentation Report. 7.2 Pre -construction Submittal Review Prior to scheduled delivery of the product, the liner contractor shall submit the following items to the CQA engineer for review: ■ The geosynthetic manufacturer's description (cut sheet) for the proposed resin and geomembrane documenting that it will meet or exceed the requirements summarized in Table 2 of this CQA Plan ■ Shop drawings showing the proposed layout of the panels, field seams, and any► other details that are needed to describe the proposed installation Prior to installation of the geomembrane, the CQA engineer shall review and approve submittals and shop drawings for conformance with the contract documents. 7.3 Material Specifications, Handling, and Storage Geomembrane used for the project shall conform to the minimum specifications detailed in Table 2 of this CQA Plan. Geomembrane shall be manufactured of first -quality resin and shall be compounded and manufactured specifically for containment applications. The geomembrane material shall be free of holes, blisters, undispersed raw materials, and any sign of contamination by foreign matter. Any such defect shall be repaired in accordance with the manufacturer's recommendations. The geomembrane shall also be protected from puncture, dirt, grease, mechanical abrasions, and excessive heat; stored on a level, prepared surface (not wooden pallets); and stacked in accordance with the manufacturer's recommendation. At all times, geomembrane material shall be handled in a manner that: ■ Prevents damage by such activities as handling, traffic, smoking, and use of equipment and tools; ■ Prevents scratching or crimping of panels during unrolling; i*15\153888th040010404 edop fnl decl6tiappendix e_cga plantiapp e nwlf cqa plan 21dec16.docx Golder Associates December 2016 22 1538880 ■ Prevents damage of the underlying liner components; ■ Prevents uplifting of in -place panels by wind; and ■ Minimizes the wrinkles (e.g., distribute across cell, avoid wrinkles at seams) and compensates for those that cannot be prevented. 7.4 Geomembrane Support Sump and riser pipe corridor surfaces to be lined with geomembrane shall be smooth and free of debris and angular or sharp rocks. The underlying compacted cohesive soil liner shall be smooth -rolled and shall not contain protrusions of stones, clods, rocks, or debris greater than 3/8 -inch. The surface of the underlying compacted cohesive soil liner shall have no sudden sharp or abrupt changes in grade. These conditions shall be certified on a daily basis by the liner contractor and/or the CQA engineer. The contractor shall protect the surface underlying the geomembrane from desiccation, flooding, and freezing until such time that placement of geomembrane begins. Protection, if required, may consist of a thin, plastic protective cover (or other material as approved by the CQA engineer) installed over the completed underlying surface. The thin, plastic protective cover may only be used as a short-term (e.g., overnight, over a weekend, or multiple days of inclement weather) measure to protect the compacted cohesive soil liner surface until the geomembrane is deployed. It shall not be used for long-term frost protection during the winter. Geomembrane deployment shall be performed as soon as practical after completion of the compacted cohesive soil liner. Long-term exposure situations shall require placement of additional protective soil over the compacted cohesive soil liner. Underlying compacted cohesive soil liner surfaces found to have significant desiccation cracking or that exhibit swelling, heaving, or other similar conditions, shall be replaced or reworked by the Contractor to repair the defects. The geomembrane shall be installed in direct and uniform contact with the underlying compacted cohesive soil liner. 7.5 Deployment 7. .1 Weather Conditions Generally, geomembrane deployment shall not occur during any precipitation, in the presence of excessive moisture (e.g., fog, dew), in an area of standing water, or during high winds (in excess of 30 miles per hour). The liner contractor shall have the final responsibility to determine if conditions are suitable for liner placement. Placement and welding of the geomembrane shall not be undertaken during periods when the air temperature six inches above the surface of the geomembrane is colder than 32°F or warmer than 105°F, unless pre -construction site weld tests for the seaming reveal adequate results at temperatures outside this range. i:115\153888th040010404 edop fnl decl6tiappendix e_cqa plantiapp e nwlf cilia plan 21dec16.docx Golder Associates December 2016 23 1538880 7.5.2 Documentation of Panel Placement Prior to placement of the geomembrane, the liner contractor and the CQA engineer shall review the panel layout drawing. Any subsequent changes of the panel layout initiated by the liner contractor shall require approval by the CQA► engineer. Information relating to panel placement including date, time, panel number, and panel dimensions shall be maintained on a panel placement form by the liner contractor. If a portion of a roll is set aside to be used at another time, the roll number shall be written on the remainder of the roll in several places. 7.5.3 Method of Deployment The method deployment of the geomembrane shall meet the following requirements: ■ The method and equipment used to deploy the panels shall not damage the geomembrane or the supporting surface. ■ No personnel working on the geomembrane shall wear shoes that may damage the geomembrane liner or engage in actions that could result in damage to the liner. ■ Adequate temporary anchoring (e.g., sandbags, tires, or other approved anchorage) that will not damage the geomembrane shall be placed to prevent uplift of the geomembrane by wind. ■ The geomembrane shall be deployed in a manner to minimize wrinkles. ■ Any area of a panel observed and noted as damaged (torn, twisted, punctured, or crimped) shall be marked and repaired or replaced. Any repaired panels shall be approved by the CQA engineer. ■ Bridging or stressed conditions in the geomembrane shall be minimized. Proper slack allowance for shrinkage shall be provided during installation and before the placement of overlying components. ■ Panels shall have a minimum four -inch finished overlap. Seams shall be oriented parallel to the line of maximum slope (i.e., horizontal seams shall not be allowed). In corners and odd -shaped geometric locations, the number of field seams shall be minimized. No base T -seam shall be closer than five feet to the toe of the slope. ■ Objects such as pipes, gas vents, manholes, sumps, and other objects that may penetrate the liner shall be connected to the liner material in such a way that prevents leakage and unnecessary stresses. 7.5.4 General Seaming/ Welding Procedures ■ Seaming shall extend to the outside edge of panels to be placed in the anchor trench. ■ While welding a seam, the proper overlap shall be monitored and maintained. ■ Seams shall be inspected to ensure that the area is clean and free of moisture, dust, dirt, and debris of any kind. ■ Welding technicians shall periodically check machine operating temperature and speed and shall mark this information on the geomembrane. ■ Wrinkles shall be aligned at the seam overlap to allow welding through the wrinkle. ■ "Fishmouths" or wrinkles at seam overlaps that cannot be welded through shall be cut along the ridge in order to achieve a flat overlap. The cut "fishmouth" or wrinkle shall be i:115\1538880\040010404 edop fnl decl6tiappendix e_cqa pla&app e nwlf cqa plan 21dec16.docx Golder Associates December 2016 24 1538880 heat -tacked flat and extruded or patched with an oval or round patch of the same geomembrane extending a minimum of three inches beyond the cut in all directions. ■ Prior to welding cross/butt seams, the top and bottom overlaps of intersecting fusion welded seams shall be trimmed six inches. Intersecting extrusion fillet -welded seams shall be ground to flatten the extrusion bead prior to welding butt seams. ■ All "T" joints produced as a result of cross/butt seams shall be extrusion fillet welded. The overlap on each "leg" of the "T" joint shall be trimmed back 6 inches. A minimum of 3 inches on each of the three legs of the "T" shall be ground, and all of the area prepared by grinding shall be extrusion welded. ■ The seam area shall be cleaned prior to seaming to provide an area that is clean and free of moisture, dust, dirt, and debris of any kind. No grinding is required for fusion welding. 7.5.5 Extrusion Fillet Welding ■ Whenever possible, extrusion -welded seams shall be pre -beveled prior to heat -tacking into place. ■ Geomembrane shall be overlapped a minimum of four inches. ■ Using a hot-air source, temporarily bond the panels of geomembrane to be welded, taking care not to damage the geomembrane. ■ Clean the seam area prior to seaming to provide an area that is clean and free of moisture, dust, dirt, and debris of any kind. ■ Prior to welding but within an hour of the welding operation, grind seam overlap in a manner that does not damage the geomembrane. Grind marks should be covered with extrudate whenever possible. In all cases, grinding should not extend more than inch past the edge of the area covered by the extrudate during welding. 7.5.6 Seaming Documentation Seaming information including panel number, seam number, welder ID, machine number, temperature setting, and weather conditions shall be documented. Welding technicians shall mark the following information on the liner with permanent markers at the start of all seaming operations: date, time, welding technician ID, machine number, and machine operating temperature and speed. All personnel performing seaming operations shall be trained and certified in the operation of the specific seaming equipment being used. The liner contractor shall provide direct supervision of the seaming operations. As -built drawings shall show locations of seams, samples cut for destructive testing, and repairs. Results of field seam test strips shall be recorded. 7.5.7 Trial Welds Trial welds for fusion and extrusion welds shall be conducted by certified welding technicians prior to each seaming period, every five hours, as weather conditions dictate, if welding problems are suspected, or at the discretion of the certifying engineer. All trial welds shall be performed under the same conditions encountered during actual seaming. Once qualified by a passing trial weld, welding technicians shall not change parameters (e.g., temperature and speed) without performing another trial weld. i*15ti153888th040010404 edop fnl decl6tiappendix e_cqa planlapp e nwlf cqa plan 21dec16.docx Golder Associates December 2016 25 1538880 1. A trial weld shall be made by joining two pieces of geomembrane that are at least six inches in width. Trial welds for fusion welds shall be a minimum of five feet long, and extrusion weld trial seams shall be a minimum of four feet long. 2. Samples shall consist of three 1 -inch -wide specimens, one from the middle of the seam and two that are each one foot from each end of the test seam. Specimens shall be obtained using a one -inch die cutter. The specimens shall then be tested in peel using a field tensiometer capable of 500 pounds of tensile force. 3. For a trial weld to be considered acceptable, all three specimens must meet the following criteria: A. They must exhibit film -tearing bond (FTB). B. They must meet or exceed the minimum strength values shown in Table 2. If any specimen should fail, the entire procedure shall be repeated. C. In the case of double -track fusion -welded seams, both welds must pass to be considered acceptable. D. If repeat tests utilizing reasonable sets of welding parameters also fail, the seaming apparatus shall not be accepted and shall not be used for seaming until the deficiencies are corrected and a passing test seam is achieved. E. Trial weld documentation: The certifying engineer or designated representative shall be present during peel testing. The liner contractor shall record the date, time, operator, machine number, ambient and operating temperatures, speed setting, peel values, shear values, and pass/fail designation. A log of recorded test values shall be maintained and shall become part of the record documents for the installation. F. In the event that non -complying seam test strips are encountered, the welding machine shall be taken out of service until a passing trial weld is obtained, and additional peel specimens shall be taken to localize the flaw. G. All acceptable seams must be bounded by two locations from which passing tests have been taken. 7.5.8 Testing The following laboratory tests shall be conducted on collected samples: ■ Shear test by method ASTM D4437 (Mod. NSF 54) or equivalent thereof; and ■ Peel test by method ASTM D4437 (Mod. NSF 54) or equivalent thereof. Testing requirements are detailed in Table 2. Non-destructive tests shall be performed over the full (100%) length of all field seams. Testing shall be by vacuum (for extrusion welds) or pressure (for double -fusion welds). Samples of field welds shall be collected at least every 500 feet for laboratory destructive testing. All holes in the geomembrane resulting from destructive seam sampling shall be repaired and tested in accordance with the following section. Archival of field weld samples shall not be required. i:115\153888th040010404 edop fnl decl6tiappendix e_cqa pla&app e nwlf cqa plan 21dec16.docx Golder Associates December 2016 26 1538880 7.6 Repairs ■ Any portion of the geomembrane or geomembrane seam showing a flaw or having a destructive or nondestructive test in noncompliance shall be repaired and non-destructively tested. ■ Repair holes larger than 114 inch with a patch; repair smaller holes by extrusion cap welding. ■ Grind and clean the surface to be patched no more than 15 minutes prior to patching. Remove no more than 10% of the thickness. ■ Patches shall have rounded corners or be oval in shape, made of the same geomembrane, and extend a minimum of six inches beyond the edge of the defects. All patches shall be of the same compound and thickness as the geomembrane specified. All patches shall have their top edges beveled with an angle grinder prior to placement on the geomembrane. Patches shall be applied using approved methods only. ■ Each repair shall be nondestructively tested, except when the CQA engineer requires a destructive seam sample obtained from a repaired seam. Repairs that pass the nondestructive test shall be taken as an indication of an adequate repair. Failed tests indicate that the repair must be repeated and retested until passing test results are achieved. ■ All acceptable seams shall be bounded by two locations from which passing tests have been taken. i:115\153888th040010404 edop fnl decl6tiappendix a cqa plantiapp e nwlf cqa plan 21dec16.docx Golder Associates December 2016 27 1538880 8.0 FINAL CONSTRUCTION DOCUMENTATION REPORT After completion of each liner or final cover construction project, a Construction Documentation Report shall be prepared and submitted to the CDPHE. The report shall consist of a detailed narrative describing construction of the area in chronological fashion. It shall describe all major aspects of construction including (as applicable): excavation, subgrade preparation, compacted cohesive soil liner placement, leachate collection system construction, granular drainage layer placement, geomembrane liner placement, and/or final cover construction. In addition, the report shall include a discussion of all changes or variances from the contract documents that were made during construction. All forms and reports relating to the installation of the geomembrane liner shall be included as appendices to the Construction Documentation Report, as referenced throughout this CQA Plan. An analysis and discussion of all field and laboratory testing work performed shall be included, including identification of any non -conforming items. For any non -conforming item, the certifying engineer shall specifically discuss whether the item is acceptable as -is, or whether further testing or additional evaluation is required for approval. A cover letter shall be included under the seal of a registered professional engineer (PE) licensed in the state of Colorado, rendering an opinion as to whether the facility has been constructed in substantial conformance to the contract documents. A registered land surveyor in the state of Colorado shall certify all survey data and documentation which shall be included in the report. A complete set of record drawings shall also be submitted along with the report. 1:115\1538880\040010404 edop fnl dec16\appendix e_cqa plantiapp e nwlf cqa plan 21dec16.docx Golder Associates TABLES December 2016 TABLE al NORTH WELD LANDFILL SOIL CONSTRUCTION QUALITY ASSURANCE TESTING AND FREQUENCY ENGINEERED FILL TESTING AND FREQUENCY 1538880 Test ASTM Designation Minimum Construction FrequencyPre Minimum n truction construction Frequency Field Density D6938 1 per 870 cy -- Field Moisture D6938 1 per 370 cy -- Field Test and Sample Selected randomly by CQA Locations D6938 Engineer predetermined within an approximate grid -- Grain Size (no hydrometer) D6918 At CQA Engineers discretion 1 material per source type and Moisture Content D2216 or D4648 At CQA Engineer's discretion 1 material per source type and Standard Proctor D698 At CQA Engineer's ineer's discretion 1 material per source type and COMPACTED COHESIVE SOIL LINER TESTING AND FREQUENCY Test ASTM Designation Minimum Construction Fre uenc y Minimum Preconstruction Frequency Field Density D6938 1 per 370 cy -- Field Moisture D6938 1 per 370 cy -- Field Locations Test and Sample __ Selected Engineer predetermined pattern randomly within offset for 100 by an approximate ft subsequent x the 100 CCA ft lifts grid -- Soil Classification D 8 7 1 type per 5,000 cy and change in material 1 per 20,000 cy Grain Size hydrometer) (no y dromatar } I 1 type per 5,000 cy and change in material 1 per 20,000 cy Atterberg Limits D4318 1 type per 5,000 cy and change in material 1 Per 20,000 c y Moisture Content D2216 D4648 or 1 per 5,000 cy 1 per 20,000 cy Standard Proctor D698 1 material per 10,000 type cy and change in 1 per 20,000 c y Modified Proctor D1557 At CQA Engineer's discretion 1 per source Hydraulic ymaterial Conductivity I D5084 1 per 10,006 type cy and change in 1 per 2O,OOO c P y Specific Gravity D854 1 type per 5,000 cy and change in material 1 per 20,000 cy One Point Proctor AASHTO T272 1 minimum per change of in 1 material per 5,000 type, cy with Ia -- 1 i:\15\1538880\0400\0404 edop fnl dec161appendix a eqa planlapp e table 1 21dec16.dacx Golder Associates December 2016 TABLE al NORTH WELD LANDFILL SOIL CONSTRUCTION QUALITY ASSURANCE TESTING AND FREQUENCY LEACHATE DRAIN AND SUMP GRAVEL TESTING AND FREQUENCY 1538880 Test ASTM Designation Minimum Construction FrequencyPreconstruction I Minimum Frequency Grain Size C136 1 samples per 1,000 LF or minimum of 2 1 per source Hydraulic Conductivity D5084 1 per 10,000 cy 1 per source GRANULAR DRAINAGE LAYER TESTING AND FREQUENCY Test ASTM Designation Minimum Construction FrequencyPreconstruction Minimum Frequency Hydraulic Conductivity* D5084 1 per 10,000 cy 1 per source * Preconstruction hydraulic conductivity tests for glass cullet to be conducted under loaded and unloaded effective stress conditions, construction tests to be conducted under unloaded effective stress conditions. FINAL COVER TESTI G AND FREQUENCY Test ASTM Cesi nation 9 Minimum Construction Fre '� uen y Minimum !reconstruction Frequency Field Density D6938 1 per 6,500 cy -- Field Moisture D6938 1 per 6,500 cy -- Field Test Locations a Selected CQA randomly Engineer by the certifying -- Grain Size D6913 1 per 6,500 cy 1 material per source and type Hydrometer y D7928 1per 6 500 c y 1 material per source type and Content D22Moisture D4548material 16 or 1 per 6,500 cy 1 per source type and Standard Proctor D698 1per 6,500 cy 1 material per source type and p H SW -846 9045C SW 1 per 6,500 c y 1 material per source type and CaCO3 USDA Handbook Number 60 1 per 6,500 cy 1 material per source type and 2 i:\15\1538880\0400\0404 edop fnl dec161appendix a eqa planlapp e table 1 21dec16.dacx Golder Associates December 2016 TABLE 2 GEOMEMBRANE CONSTRUCTION QUALITY ASSURANCE TESTING AND FREQUENCIES 1538880 Item Parameter Specification Test Method Construction Frequency , rR econstruction Frequency Survey/Comments HQPE Resin Gravity greater than or equal to 0.932 ASTM D792 Method A 9.Specific Manufacturer: 1 per resin batch Resin without carbon black Melt Index max 1.0g per 10 minutes ASTM D1238 Condition E Specific Gravity greater than or equal to 0.94 ASTM D792 Method A N/A Extrudate Rod or Bead Carbon Black Content 2-3% ASTM D1603 Melt Index max 1.4q per 10 minutes , ASTM D1238 Condition E Thickness 54 -mils minimum, average of 10 tests 60 mils ASTM D5994 5 per sidef5 per end WA Panel Record Drawing to be prepared by Registered Kansas Land Surveyor Compound Density greater than or equal to 0.94 ASTM D792/1505 Manufacturer: 1 per lot Carbon Black Content 2-3% ASTM D1603 Carbon Black Dispersion Minimum 9 views category 1 or 2, No more than 1 view from category 3. ASTM D5596 Strength at Yield Minimum 126 Ibsfin ASTM D638 Geomern bra ne (60 mil HDPE Liner) Elongation at Yield Minimum 12% ASTM D638 Strength at Break Textured: Minimum 90 Ibsfin ASTM D638 N/A Smooth: Minimum 228 Ibsfin Elongation Break Textured: Minimum 100% A ASTM D638 at Smooth: Minimum 700% Tear Strength Minimum 42 lbs. ,,, ,ASTM D1004 Textured: Minimum 90 Ibsfin ' Puncture Resistance Smooth: Minimum 108 Ibsfin ASTM D4833 Destructive Tests Fusion Weld or Extrusion Fillet Testing Peel: Greater than greater than 120 lbs. 78 lbs.; Shear ASTM D6392 1 per 500 feet of seam length, Observation of each destructive sample WA Based on Specifications Set forth by Geosynthetics Research Institute, March 2002 (60 -mil HOPE Liner) Trial Seam Testing: Fusion ASTM D6392 1 per shift or 1 per 5 hours, a Trial Seam Testing: Extrusion ASTM D6392 Observation of each destructive sample Non-destructive Tests Fusion Weld Continuity by air -pressure testing 27 to 35 psi for 5 minutes; permissible drop of 3 psi ASTM D5820 Each Seam NIA (60 -aril HOPE Liner) . Extrusion Weld Continuity by vacuum- box testing induce pressure of 5 psi; hold for 10 seconds ASTM D5641 Each Seam I:t15V538880%0400'x.0404 EDQr' FNL DEC16hAppendix E CQA rIan,App E Table 2 21 DEC1a.xlsVrable D-1 GYitvic Golder Associates December 2016 Notes: TABLE 3 SEED MIX AND SOIL AMENDMENTS GRASS SPECIES Common Name i Variety Lbs PLS/Acre Buffalo Grass I Texoka 2.8 Blue Grama . Hachita 0.8 Switchgrass Dakotah 1.2 side -oats Grama Vaughn 1.6 Sand Dropseed Native 0.02 Western Wheatgrass Arriba 4.4 Slender Wheatgrass - Prim ar or Revenue 3.8 Thickspike Wheatgrass Critana 1 Little bluestem Cimmaron 2.2 Total 17.82 1538880 A. The CQA Engineer shall inspect seed labels/certifications upon delivery of seed to worksite to ensure that they contain correct seed mix. Native seed varieties shall be from appropriate climatic region. All legume species shall be inoculated by the seed supplier with the appropriate rhizobium species. Sources for native seed variety shall be subject to inspection and concurrence by the CQA Engineer before subcontractor is authorized to proceed with seeding. B. Perform seeding operations only during periods when successful results can be obtained (i.e., not during drought or excessive precipitation periods). Do not conduct seeding operations when soil is frozen or when snow is present. Do not conduct seedbed preparation, seeding, or mulch application when wind conditions cause the seed/mulch to blow from the intended target area. C. Seedbed preparation shall be conducted to maintain existing drainage patterns or as indicated on the project - specific drawings. Re -till areas compacted by construction. Protect finished graded areas from damage by vehicular or pedestrian traffic and erosion. Prior to seeding, rework any previously prepared seedbed areas compacted or damaged by rain, traffic, or other cause to restore the seedbed to previous condition. D. Seeding times shall be: fall seeding: September 1 until freezing conditions; spring seeding: March 1 through May 15. Perform seeding within 10 days of completion of seedbed preparation. E. Plant by drill seeding or by evenly broadcasting and incorporating the seed into the soil surface by harrowing. Drill seeding will be accomplished with a rangeland type drill equipped with double coulter furrow openers and depth bands followed by packer wheels. Use a drill capable of evenly seeding the native seed mixes over the entire site. Do not exceed 6 inches between drill rows. Plant seed to an average depth of 0.25 inch but not deeper than 0.50 inch. F. If broadcast seeding is used, seeding rate shall be increased by 50%. Broadcast seed shall be distributed uniformly. Rake seed into the soil to an average depth of 0.25 inch but not deeper than 0.50 inch by a harrow device. G. Fertilization and seeding mix shall be finalized after agricultural analysis of topsoil. H. Spread and anchor grass straw mulch on areas that have been seeded with fall -seeded mixes within 24 hours after seeding. Apply straw mulch in a continuous cover of uniform thickness at a rate of 2 tons per acre. Anchor straw mulch to the soil by crimping straw into the soil. Start mulching on the windward side of relatively flat areas or on the upper part of steep slopes and continue uniformly until the area is covered. Immediately after seeding, protect seeded areas against traffic or other use by erecting barricades and providing signage. Re -till, seed, and mulch any areas impacted by traffic as directed by the contractor. I. Repair: Reseed and mulch eroded, damaged, or barren areas that occur prior to completion of the seeding operation as determined by the Contractor. Repair or replace mulch as required. i:\15\1538880\0400\0404 edop fnl decl6lappendix e_cga planlapp e table 3 2ldecl6.docx Golder Associates APPENDIX F WASTE IDENTIFICATION PLAN IRIAST MANAGEMENT WASTE IDENTIFICATION PLAN North Weld Landfill 40,000 Weld County Road 25 Ault, Colorado 80610 December 2016 Prepared by: Waste Management Disposal Services of Colorado, Inc. 5500 S. Quebec St., Suite 250 Greenwood Village, CO 80111 ERRATA - FOR INTERIM UPDATES NORTH WELD LANDFILL WASTE IDENTIFICATION PLAN DATE DESCRIPTION OF CHANGE April 2002 Addition of Errata Sheet and replacement of Generator Waste Profile Sheet October 2002 December 2005 June 2013 December 2016 Plan revised pursuant to CDPHE letter dated July 10, 2002 Plan updated pursuant to SB 05-141 and replaced Unacceptable Load Notification with. Load Rejection Report Plan updated pursuant to SB 12-133 banning all electronic waste as defined in Section 16 of the Regulations Pertaining to Solid Waste Sites and Facilities Plan updated to include acceptance and handling procedures for sludge and marijuana. Other minor revisions made to text and appendices. TABLE OF CONTENTS 1.0 2.0 PURPOSE.��!*M��Y�*��lMail��..��.r•M��Y•�s�i�4�i��sw•4��l�M��•44�l�i��44�4��l��*44�E4�Ri��4�l�l�®*44�E4�REl�*44�4�1� JJ" FI ONS•00 !00•00i•iiiii•i••410041!•04141 •0410iiiii.0•0• !! 0011!i!i•iii 006iii#iii OM4iii0.004100000.0000.00410.00i1.l00• 3.0 WASTE IDENTIFICATION TION PROGRAM eat 011004100410000410000•00000411•11000011••••••00•1100041****se 1 1 3.1 P R.O HIB I TE D WASTE S .... s.........5 3.2 WASTE S CREENWTGPROLES S 5 3.3 WASTE TYPE DOCUMENTATION ...........5 4.0 LABORATORY TORY USAGE ...:... ®..s.......................................................................... w w w 4.1 ANALYTICAL REQUIREMENT S ..... 6 4.2 ACCEPTABLE LABORATORIES ................. 6 5.0 TRAINING sees 000 testik••••.•it••l•iei!•a..•lnflii•.ii/ill••46000004 eefi#efl.ee.ss.•.0iiee.n et.ee.ileiil• 6.0 OPERATIONAL REQUIREMElNT �� .. , .� .� �� . �..�.� �®..�.� �a� �. �• 7.0 0000400000,000.0011000 6 6 PROGRAMl ECORI •004 04.0000000000.0000000410s•f••••r.•s••••04 04.00000rs 04110•00r0aasfass•fr!!!isl•••••••OMGO 7 Attachment A Attachment B Attachment C ATTAC ETS Waste Inspection Report Sheet Generator's Waste Profile Load Rejection Report 1.0 PURPOSE Waste Management Disposal Services of Colorado, Inc. (WMDSC) has adopted a Waste Identification Plan (Plan) for the North Weld Landfill (NWLF) to screen regulated hazardous waste, radioactive waste, polychlorinated biphenyl (PCB) waste, infectious waste, certain wastes related to motorized equipment, electronic waste, and waste tires to prevent these waste streams from entering the facility. The Plan also serves to identify commercial and industrial wastes that may require special handling from an employee or public safety perspective. Compliance with the Plan will also ensure compliance with the waste screening requirements of Section 2.1.2 (B) of the Colorado Department of Public Health and Environment (the Department), "Regulations Pertaining to Solid Waste Disposal Sites and Facilities", CCR 1007-2, amended November 17, 2015, hereinafter referred to as "the Regulations." ;0 EFINITIONS Commercial Waste - In accordance with 6 CCR 1107-2 Section 1.2, "all solid wastes generated by stores, hotels, markets, offices, restaurants, warehouses, construction and demolition debris and other non -manufacturing activities, excluding community and industrial wastes." Electronic Device -- A device that is marketed by a manufacturer for use by a consumer and that is a computer, peripheral, printer, facsimile machine, digital video disc players, video cassette recorder, or other electronic device specified by rule promulgated by the commission; or a video display device or computer monitor including a laptop, notebook, ultrabook, or netbook computer, television, tablet, or slate computer, electronic book, or other electronic device specified by rule promulgated by the commission that contains a cathode ray tube or flat panel screen with a screen size that is greater than four inches, measured diagonally. "Electronic device" does not include a device that is part of a motor vehicle or any component part of a motor vehicle, .including replacement parts for use in a motor vehicle; a device, including a touch -screen display, that is functionally or physically part of or connected to a system or equipment designed and intended for use in any of the following settings, including diagnostic, monitoring, or control equipment: industrial; commercial, including retail; library checkout; traffic control; security, sensing, monitor, or counterterrorism; border control; medical; or governmental or research and development; a clothes washer or dryer; a refrigerator, freezer, or refrigerator and freezer; a microwave oven or conventional oven or range; a dishwasher, a room air conditioner, dehumidifier, or air purifier; or exercise equipment; a device capable or using commercial mobile radio service, as defined in 47 CFR 20.3, that does not contain a video display area greater than four inches, measured diagonally; or a telephone. Hazardous Waste - Those substances and materials defined or classified as such by the Colorado Solid and Hazardous Waste Commission pursuant to 25-15-302, C.R.S., as amended. North Weld Landfill 1 Waste Identification Plan, December 2016 Hazardous Waste Facility - facility that has received all required U.S., Mexican or Canadian Federal or State/Provincial approvals, licenses, or permits necessary to receive and manage Hazardous Waste. Industrial Waste - All solid wastes, including milltailings and mining wastes, resulting from the manufacture of products or goods by mechanical or chemical processes that are not a hazardous waste regulated under 6 CCR 1007-3, the Colorado Hazardous Waste Regulations. Such waste may include, but is not limited to, waste resulting from the following manufacturing processes: electric power generation; fertilizer/agricultural chemicals; food and related products/byproducts; inorganic chemicals; iron and steel manufacturing; leather and leather products; nonferrous metals manufacturing/foundries; organic chemicals; plastics and resins manufacturing; pulp and paper industry; rubber and concrete products; textile manufacturing; transportation equipment; and water treatment. This term does not include oil and gas wastes regulated by the Colorado Oil and Gas Conservation Commission. Infectious Waste - Waste containing pathogens or biologically active material which because of its type, concentration and quantity could present a potential hazard to human health when improperly handled, stored, processed, transported or disposed of. Wastes presumed to be infectious medical waste include blood and body fluids, potentially infectious waste, patho to gical waste, sharps, trauma scene waste, and any additional waste determined to pose a sufficient cient risk of infectiousness as determined by the Department on a case -by case basis. This also includes any residue or contaminated soil, water, or other debris resulting from the cleanup of a spill of any infectious medical waste. For purposes of the Regulations, it does not include saliva, nasal secretions, sweat, tears, used feminine hygiene products, vomitus, urine or feces unrelated to isolation wastes, uncontaminated disposable bedding or garments, or lightly to moderately contaminated bandages, garments, etc. unless these wastes are soiled to the extent that the generator of the waste determines that they shouldbe managed as infectious waste. Such wastes remain regulated under the provisions of Parts 1 through 3 of the Regulations. Lead -Acid Battery battery that: a. consists of lead and sulfuric acid; b. is used as a power source; and c. is not intended as a power source for consumer products. Liquid Waste - Any waste that is determined to contain "free liquids" as determined by Method 9095 (Paint Filter Liquids Test), described in "Test Methods for Evaluating Solid Waste, Physical/Chemical Methods: USEPA Publication SW -846". According to 40 CFR 258.28, this definition does not include waste in containers similar in size to that normally found in household waste (e.g., beverage containers). Marijuana Waste — Refers to confiscated, medical, or recreational marijuana; by- products; plants; and/orresidues; including those from grow operations, to be disposed in accordance with 6 CCR 1007-2 and either 1 CCR 212-2M 307 or R 307. North Weld Landfill 2 Waste Identification Plan, December 2016 Municipal Solid Waste - Solid waste from household, community, commercial and industrial sources that does not contain hazardous wastes as defined in Section 25-15- 101(6)(a) of the Colorado Hazardous Waste Act unless otherwise regulated by CDPHE. NWLF — North Weld Landfill Radioactive wastes - Wastes handled at facilities licensed pursuant to the provisions on radiation control in Article 11 of Title 25, C.R.S. Residentially generated used lead -acid batteries, used oil or tires - Any used lead -acid batteries, used oil or waste tires generated by a person. esidual Sludge — Any solids, semi -solids, or liquids remaining in a waste impoundment after final evaporative or other treatment or storage of the waste is completed, or which may be dredged out during the active life. Sludge — Any solid or semi -solid waste generated by a municipal, commercial, or industrial wastewater treatment plant, water supply treatment plant, or air pollution control facility. Solid Waste - Any garbage, refuse sludge from a waste treatment plant, water supply treatment plant, air pollution control facility, or other discarded material; including solid, liquid, semisolid, or contained gaseous material resulting from industrial operations,. commercial operations or community activities."Solid waste" does not include any solid or dissolved materials in domestic sewage, or agricultural wastes, or solid or dissolved materials in irrigation return flows, or industrial discharges which are point sources subject to permits under the provisions of the "Colorado Water Quality Control Act", Title 25, Article 8, CRS or materials handled at facilities licensed pursuant to the provisions in "Radiation Control Act" in Title 25, Article 11, CRS. Solid Waste Management - Transportation, transfer, storage, treatment, reclamation, incineration or disposal of solid waste. Special Waste Handling - Any waste that causes WMC to alter standard collection, transportation, processing, manifesting or landfilling practices for safety, health, regulatory or environmental reasons (e.g., immediate burial, worker protection, solidification, bioremediation, analysis, engineering controls, or any other special preparation to receive the waste). SW -846 Methods - The latest edition of "Test Methods for Evaluating Solid Waste, Physical/Chemical Methods" USEPA Publication SW -846. Used oil - Any residentially generated motor oil, refined from crude oil or a synthetic oil that has been used and as a result of that use is contaminated by physical or chemical impurities. North Weld Landfill 3 Waste Identification Plan, December 2016 Waste Tire - tire that is modified from its original specifications but not processed into a tire -derived product, is no longer being used for its initial intended purpose, and is not a used tire.. North Weld Landfill 4 Waste Identification Plan, December 2016 3.0 WASTE EVALUATIONPROGRAM Although it is the generator's responsibility to accurately characterize its waste, the procedures identified in this Plan will be implemented to screen waste produced by commercial and industrial customers for regulated hazardous, PCB and radioactive wastes, wastes generated by residential customers related to motorized equipment, electronic waste, and waste tires. Evaluations may be made by physically reviewing commercial and industrial processes, laboratory analysis, written survey, phone questionnaires or other methods, which will identify prohibited wastes or wastes requiring special handling. Prohibited wastes that are identified during the waste evaluation program will be referred to a permitted hazardous waste transfer, storage or disposal facility or other appropriate facility. Additional questions and/or observations of incoming wastes are completed at the gatehouse and a minimum of two (2) random load inspection per week are completed at the disposal area. The waste inspection report form included in Attachment A will be used. If prohibited wastes are discovered at the facility, the procedures described in Section 6.0 of this Plan will be followed. 3.1 PROHIBITED WASTES egulated hazardous, radioactive, PCB, or infectious wastes, which are subject to Q.T.S. or Colorado regulations will not be accepted at NWLF. Other wastes that are banned include residentially generated lead -acid batteries and used oil, waste tires, and electronic devices. Generators with these wastes will be referred to an appropriately permitted facility. 3.2 WASTE SCREENING PROCESS An acceptance decision to approve a waste stream will be documented for certain industrial and commercial waste stream destined for disposal at NWLF. The following requirements will be followed prior to acceptance of certain industrial and commercial wastes: • The customer or its agent must provide information about the waste and sign a waste profile (a facsimile signature is acceptable). A sample waste profile is included in Attachment B. • The profile and associated information will be reviewed. Material characterized as prohibited waste will not be accepted. The information provided by the generator will be used to assign any appropriate co nditio ns/limitations on managing the waste. • The waste profile must be updatedif the process generating the waste changes. 3.3 WASTE TYPE DOCUMENTATION The waste profile will be completed and signed by the generator or his designee for specific waste streams managed at NWLF. The generator must complete the form North Weld Landfill S Waste Identification Plan, December 2016 to the best of his/her knowledge in accordance with the instructions attached to the profile. Prior to the expiration date of the waste profile approval, the underlying facts concerning the waste stream will be re-examined and a decision rendered in accordance with Section 3.2 whether to continue managing the waste. Any changes made to the written information provided by the generator will be initialed and dated by the person authorizing the changes. Facsimile changes are acceptable. If these changes affect the precautions, conditions, or limitations for managing the waste, the generator will be informed in writing of the changes. 4.0 LABORATORY USAGE E 4.1 ANALYTICAL TICAL REQUIREMENTS DSC personnel will review the waste profile and any analytical results or equivalent information (i.e., 40 CFR 262.11 allows generator's knowledge of the waste and process generating the waste) to screen waste from certain commercial and industrial customers so that prohibited wastes are not accepted. 4.2 ACCEPTABLE LABORATORIES A commercial or private laboratory, using SW -846 or equivalent approved test methods acceptable to WM' IDSC will be used for conducting any required waste analyses . 5.0 TRAINING All employees responsible for waste acceptance or inspection will be trained, at a minimum, to recognize and properly respond to prohibited and banned wastes. 6.0 OPERATIONAL REQUIREMENTS If prohibited wastes are identified at the facility, the material will be rejected and returned to the generator if possible or segregated until adequate information can be obtained to accurately identify the waste and determine an appropriate management method. CDPHE and Weld County authorities will be notified as required. Additionally, efforts will be taken to identify the generator of the material. A "Load Rejection Report" form (Attachment C) will be completed and filed in the site operating record. Marijuana waste will only be accepted in accordance with M 307 or R 307 of the Colorado Department of Revenue regulations. The requirements include receipt of marijuana waste that has been rendered unusable and unrecognizable through grinding and incorporating the marijuana waste with non -consumable, solid wastes including paper waste, plastic waste, cardboard waste, food waste, grease or other compostable oil waste, Bokashi, or soil such that the resulting mixture is at least 50 percent non -marijuana waste. Sludge will be acceptedat the working face in a manner to prevent customers and the public from coming into contact with the sludge. This can be accomplished by pushing the sludge into the working face prior to allowing other customers in the immediate area where the sludge was dumped or preparing a trench, so the sludge can be pushed into the trench and covered with other solid waste. North Weld Landfill 6 Waste Identification Plan, December 2016 7.0 PROGRAM RECORDS Records will be maintained in accordance with applicable regulations. All documents will be maintained at the facility or an alternative location approved by the Department. North Weld Landfill 7 Waste Identification Plan, December 2016 ATTACHMENT A WASTE INSPECTION REPORT WASTE INSPECTION REPORT Date: Hauler: Time: Truck #: Inspector: Ticket #: (Print Name) Are the following wastes present in the load? Yes No Waste Requiring Special handling? Regulated Hazardous Waste? Radioactive Waste? PCB Wastes? Infectious Waste? Liquid Waste? Residentially batteries or generated used used oil? lead -acid Electronic Waste? Waste Tires? Comments: ATTACHMENT B GENERATOR'S WASTE PROFILE SHEET WASTE NfANAGEM ENT 780 East 96th Avenue, Henderson, CO 80640 • (303) 336-3900 • Fax: (303) 280-9848 GENERATOR'S WASTE PROFILE SHEET WM Use Only Expiration Date: Technical Approval By: Approval Date: Profile # Safety/Health Review By: Limitations: INSTRUCTIONS: Please answer each question as completely as possible by circling "YES" or "NO", checking the appropriate boxes, filling in the blanks, and attaching additional sheets as necessary. An ink pen or typewriter must be used. The Generator or an Authorized Representative must sign the form. All related analyses and associated chains of custody must be included with the form. If the waste changes or future analyses differ from what was submitted, WIVI must be notified immediately. Originals must follow fax or email copies. Please check the box below indicating the landfill where you would like your waste managed: ❑ DADS ❑ CSI ❑ NWLF ❑ MIDWAY ❑ CSLF ❑ BRL ❑ MONTROSE ❑ OTHER (Specify below) FOR `OTHER': Provide Name and Address of Management Facility: A. GENERATOR INFORMATION Generator Name: Generator Contact: Generator Address: Phone: Fax: Generator Title: BROKER INFORMATION (if applicable) P.O. Broker Broker Phone: # Name: Contact: Account #: Billing Address: Phone: Fax: Fax: B. PROCESS GENERATING WASTE (Based on 40 CFR 261 and 6 CCR 1007.3 Part 261) Waste Name: Mode of Shipment: ❑ Bulk Liquid ❑ Bulk Solid ❑Drums (55 gallon), ❑ Other (specify below) For OTHER: Process Generating Waste: Estimated Volume: ❑ Gallons, ❑ Cubic yards, ❑ Drums (55 gallon), ❑ Other (specify below) OTHER (Specify type and quantity): Describe the business of generator: Frequency Per: ❑ Day ❑ Month ❑ Year ❑ One Time ❑ Project C. WASTE PROPERTIES Profile #: Appearance: pH: Specific Gravity: Physical State: Liquid Flashpoint Color: ❑ < or equal to 2 ❑ < 0.8 ❑ oil (closed cup): ❑ 2.1— 7 ❑ 1.0-1.7 ❑ Liquid (water) ❑ <140() F (60° C) Odor: ❑ 7-12.4 ❑ >1.7 ❑ Sludge ❑ 140°- 200° F ❑ None ❑ > or equal to 12.5 ❑ actual ❑ Damp solid ❑ > 200 c° F ❑ Mild ❑ N/A -Solid ❑ N/A ❑ Dry solid ❑ actual ❑ Strong ❑ Powder ❑ Non -Ignitable solid ❑ Filter cake Viscosity: Total SuspendedSolids ❑ Soil Attachments: Phases: (Similar to) (% wt0: ❑ Concrete Material Safety Data ❑ Debris Sheet(s) ❑ Single ❑ <0.5 g ❑ Solid ❑ Lab pack ❑ Analytical Data ❑ Bi-layered ❑ 0.�-2.0 �' y ❑ Tar ❑ Ash ❑ Other(Agency( ❑ Multi -layered y ❑ Honey ❑ - 2 5 ❑ Motor Oil ❑ 6-20 correspondence, Paint Filter Test: ❑ ❑ >20 process knowledge water ❑ Pass statement, etc.) actual ❑ Fail NIA D. REGULATORY QUESTIONS (Based on 40 CFR 261 and 6 CCR 1007.3 Part 261) 1. Is Code), 2. Is also 3. Section where 4. Is the (UHC's) 5. Is Order; 6. Does Is the the the the the Agency check waste the waste waste • the 261.31 waste waste 261.4? are Hazardous waste exclusion 'YES' being notification from a from present. hazardous (F specifically contain Code), on If legally any an `YES', is the (WM of waste UST _following mentioned. regulated and the waste 261.32 treated can in corrective excluded attach a following? another certification provide as (K for quantities defined question) Code), from an a State; action single explanation a • blank CERCLA by 261.33 that hazardous • of 6CCR as hazardous Subject radioactives no noti defined (P Underlying f 1007-3 including ica project; to or U waste characteristic? tionkerti Land under Codes)? or Part regulations • PCB's? the In Disposal 40 Hazardous 261 f ication response CFR portion Sections If Restrictions (Attach Part firm, in so, Constituents to of 280? 6 attach a analyses) the i Compliance 261.21-24 CCR f needed.) (If regulation a 1007-3 copy TES; (D of ❑YES NO ❑YES ❑ NO ❑YES ❑ NO ❑YES ❑ NO ❑YES NO ❑YES NO E. AUTHORIZED SIGNATORY: I hereby cer t fy that: • I am the Generator (or authorized by the Generator identified herein to provide the information submitted in this farm and any attached documents and to enter into this Agreement on the Generator's behalf). • I have made a complete and thorough investigation of all matters relevant to completion of this form and based on this investigation certify that no hazardous waste codes are associated with this waste stream. • If laboratory analysis was used to evaluate this waste stream, the analysis was performed on a representative sample of the waste stream in accordance with 6CCR 100 7-3 Section 261.204). • All applicable information concerning the waste stream has been provided in this and the attached documents. Such information is complete and accurate and all known or suspected hazardous constituents/characteristics or safety hazards associated with the waste stream have been disclosed herein. • I will inform Waste Management r; f the waste characteristics or process changes. Signature: Print: Date: Title: Company: ATTACHMENT C LOAD REJECTION REPORT Load Rejection Report Date: Time: A.M. P.M. CUSTOMER/GENERATOR Name: Address: City, State, Zip: TRANSPORTER/HAULER U Same as Customer/Generator Name: Address: City, State, Zip: ORIGIN OF LOAD INFORMATION Location: Street Address: City, State, Zip: e REASON FOR REJECTION Liquid Waste Suspected. Hazardous or PCB Waste Suspected Infectious Waste Suspected Friable Asbestos Electronic Waste Other (See Comments) Explanation: ACKNOWLEDGEMENT Rej ected Prior to Dumping Comments: Rejected After Load Was Dumped Driver's Signature Site Signature Customer/Generator Notified If yes, name of person contacted: Yes No Transporter/Hauler Notified Yes If yes, name of person contacted: No APPENDIX GROUNDWATER MONITORING ORING PLAN WILL BE REPLACED WITH CURRENT GWMP ONCE REVISED TO INCLUDE UNIT 2 FOLLOWING PERMIT APPROVAL APPENDIX H OPERATIONAL PERSONNEL INFORMATION North Weld Landfill 1538880 APPENDIX H Facility Management Names, Addresses, and Experience William Hedberg Senior District Manager North Weld Landfill 40,000 Weld County Road 25 Ault, CO 80610 (970) 545-5009 25+ years of experience Tom Schweitzer Facility Engineer Waste Management Disposal Services of Colorado, Inc. 2400 West Union Avenue Englewood, CO 80110 (303) 914-1445 25+ years of experience Doc Nyiro Environmental Protection Manager Waste Management Disposal Services of Colorado, Inc. 5500 South Quebec Street, Suite 250 Greenwood Village, CO 80111 (303) 486-6034 25+ years of experience Updated December 2016 i:\15\1538880\0400\0404 edop MI decl6\appendix h_operational personnel infarmationlapp h faciity mgmt names.doc Golder Associates APPENDIX I UNIT 2 ALTERNATIVE LINER DEMONSTRATION w ce. z O ALTERNATIVE LINER DEMONSTRATION North Weld Landfill, Unit 2 Weld County, Colorado Prepared By: Golder Associates Inc. 44 Union Boulevard, Suite 300 Lakewood, CO 60228 Prepared For: Waste Management Disposal Services of Colorado, Inc. North Weld Landfill 40000 Weld County Road 25 Ault, CO 80610 December 21, 2016 tGo1der Associates 1538880 Golder, Golder Associates and the GA globe design are trademarks of Golder Associates Corporation December 2016 1538880 Table of Contents 1.0 INTRODUCTION 1 1.1 Background 1 1.2 Purpose and Objective 1 1.3 Methodology 1 1.4 Proposed Alternate Liner System 2 1.4.1 Alternative Liner System Components 2 1.4.2 Construction Qualify Assurance 2 1.4.3 Material Availability 3 2.0 CONCEPTUAL HYDROGEOLOGIC SITE MODEL 4 2.1 Geologic Setting 4 2.2 Hydrogeologic Setting 4 3.0 LEACHATE SOURCE ANALYSIS 6 3.1 Operational Scenarios 6 3.2 HELP Input Parameters 6 3.2.1 Meteorological Data 6 3.2.2 General Design Inputs 6 3.2.3 HELP Material Layers 7 3.3 Results 7 4.0 EVALUATION OF IMPACT ON GROUNDWATER QUA,►LITY 9 4.1 Dilution Factors (DFs) 9 4.2 MULTIMED Input Parameters 11 4.2.1 General Parameters 11 4.2.2 Source Parameters 11 4.2.2.1 Source Geometry 11 4.2.2.2 Source Infiltration Rate 11 4.2.2.3 Outside Recharge Rate 12 4.2.2.4 Initial Leachate Concentration 12 4.2.2.5 Source Duration and Decay Constant 12 4.2.2.6 Initial Spread of Source 12 4.2.3 Chemical Parameters 12 4.2.4 Hydrogeologic Properties 12 4.2.4.1 Unsaturated Zone Flow and Transport Properties 13 4.2.4.2 Saturated Zone Properties 15 4.2.5 Point of Compliance (POC) Location 15 4.2.6 Time Parameters 16 4.3 MULTIMED Model Results 16 4.3.1 Steady-state Results 16 i:11511538880M0ffia404 edop fnl decl6\appendix i_alternative liner demonstration\app i aid report 21dec16.docx Golder Associates December 2016 ii 1538880 4.3.2 Transient Results 17 5.0 CONCLUSIONS 19 6.0 REFERENCES 20 List of Tables Table 1 Table 2 Table Table 4 Table 5 Table 6 Initial Leachate Generation Analysis HELP Model Results MCLs, Leachate Input Concentrations, and DAF Requirements MULTIMED Input Parameters — Unsaturated Zone Flow and Transport Properties MULTIMED Input Parameters — Saturated Zone Properties MULTIMED Steady-state Analysis Results MULTIMED Transient Analysis Results List of Figures Figure 1 Alternative Liner System Detail Figure 2 Point of Compliance List of Appendices Appendix A HELP Model Output Appendix B MULTIMED Model Output Appendix B-1 Steady-state Model Results Appendix B-2 Transient Model Results i:115ti15388801040010404 edop Inl dec161appendix i_alternative liner demonstration\app i ald report 21dec16.docx Golder Associates December 2016 1 1538880 1.0 INTRODUCTION 1.1 Background The North Weld Landfill (NWLF) is a municipal solid waste landfill (MSWLF) owned and operated by Waste Management Disposal Services of Colorado, Inc. (W MDSC) in Weld County, Colorado. The NWLF received a Certificate of Designation (CD) from the Weld County Board of County Commissioners on June 27, 1990, authorizing the development of four landfill phases for solid waste disposal (identified as Phases 1, 2, 3A, and 3B), which provided approximately 122 acres of waste disposal area. This disposal area is hereinafter referred to as the Unit 1 waste disposal area. The Updated Design and Operations Plan for the North Weld Sanitary Landfill (Rust 1997) for the Unit 1 waste disposal area, approved by the Colorado Department of Public Health and Environment (CDPHE) and the Weld County Department of Public Health and the Environment (WCDPHE), and Condition 7(b) of the WCDPHE CD Development Standards required that the entire landfill be underlain by a two -foot -thick compacted clay liner. 1.2 Purpose and Objective WMDSC DSC plans to further the productive life of the NWLF through the development of Unit 2, which will be located immediately north of, and contiguous to, the existing Unit 1 waste disposal area and will add an additional 155 acres of waste disposal capacity to the site. The same alternative liner system previously approved for Unit 1 is proposed for Unit 2. In accordance with Section 3.2.5(C)(4) of the CDPHE P H E "Regulations Pertaining to Solid Waste Sites and Facilities," 6 CCR 1007-2, Part 1 as amended November 17, 2015 (Regulations) (CDPHE 2015), it is the responsibility of the owner or operator of a landfill to demonstrate that an alternative liner system design will ensure that the maximum contaminant levels (MCLs) listed in Table 1 of 40 CFR 258.40 will not be exceeded in the uppermost aquifer at the relevant point of compliance (POC). The purpose of this Alternative Liner Demonstration (ALF) is to demonstrate that the alternative liner system proposed for the development of Unit 2 at the NWLF reasonably ensures groundwater protection considering expected waste characteristics, site construction, and site setting. Groundwater protection is demonstrated in this report through technical evaluation and modeling that MCLs listed in Table 1 of 40 CFR 258.40 will not be exceeded at the Unit 2 POC. 1.3 Methodology The following methodology was used to demonstrate the performance of the alternative liner system: 1. Define geotechnical characteristics of proposed alternative liner system; 2. Develop conceptual site hydrogeologic model; i*15\15388801040M0404 edop fnl decl6\appendix i_alternative liner demonstration\app i ald report 21dec16.docx Golder Associates December 2016 2 1538880 3. Evaluate leachate generation and impingement rates through alternative liner system using Hydrologic Evaluation of Landfill Performance (HELP) model, version 3.07 (U SALE 1997); 4. Demonstrate that selected leachate chemical constituents will not exceed their MCL listed in Table 1 of 40 CFR 258.40 at the Unit 2 POC by calculating and applying dilution factors (DFs) using the Multimedia Exposure Assessment (MULTIMED) model for Windows, Version 1.51 (AGC 2005); no attenuation factors were applied for conservatism; 5. Compute constituent concentrations at the POC based on site -specific leachate analytical data and/or published leachate data and the calculated DFs; and 6. Compare computed concentrations with allowable MCLs Ls to evaluate alternative liner system performance. 1.4 Proposed Alternate Liner System 1.4.1 Alternative Liner System Components The alternative liner system for Unit 2 will be identical to the alternative liner system previously approved for Unit 1, consisting of the following components listed from top of liner down to existing foundation material: ■ A 6 -inch -thick granular leachate collection drainage layer installed over the liner floor area and composed of soils exhibiting a hydraulic conductivity equal to or greater than 1 x 10-2 cm/sec; ■ A six -inch -thick protective soil layer installed over the liner side slope area; ■ A 24 -inch -thick compacted cohesive soil liner composed of on -site or imported soils exhibiting a hydraulic conductivity no greater than 1 x 10-7 cm/sec; and ■ Prepared subgrade material composed of conditioned and compacted existing subsurface material. A detail of the alternative liner system is shown in Figure 1. Within permanent leachate collection sumps, the thickness of the compacted cohesive soil liner will be extended to 30 -inches, and a second liner (60 -mil HDPE geomembrane) will be installed to create a composite liner system where leachate head may accumulate. For conservatism, these additional design features were not considered in estimating leachate impingement rates through the alternative liner system. 1.4.2 Construction Qualify Assurance The alternative liner system will be constructed under a comprehensive Construction Quality Assurance (CQA) Plan (Golder 2016) to verify► that the liner components are prepared and installed as intended in the design. During liner construction, CQA monitoring, sampling, and testing will be required for the following properties, providing a level of confidence that the alternative liner system will be constructed as modeled in this ALF and as required to ensure performance: ■ Grade control ■ Soil classification (ASTM D2487) i:115\15388801040M0404 edop fnl decl6\appendix i_alternative liner demonstration\app i ald report 21dec16.docx Golder Associates December 2016 3 1538880 • Grain size (ASTM D422) • Atterberg limits (ASTM D4318) • Moisture content (ASTM D2216 or ASTM D4643) • Compaction characteristics (ASTM D698) IN In -place moisture content and density (ASTM D6938) I Hydraulic conductivity (ASTM D5084) Following each liner construction project, a certification report will be prepared to document that the liner and leachate collection systems were constructed in accordance with the contract documents, EDOP requirements, and approved CQA Plan. The certification report will be signed and sealed by a professional engineer (PE) registered by the State of Colorado and submitted to the CDPHE and the WCDPHE for approval prior to placement of waste. 1.4.3 Material Availability In support of the siting and engineering design of Unit 2, WMDSC commissioned a comprehensive geotechnical and hydrogeologic site characterization field program of the proposed Unit 2 area of the NWLF site. The results of the site characterization are presented in the Report of Geotechnical Investigation, North Weld Landfill Unit 2, Permitting and Development (Swift River 2016a) and Report of Hydrogeological Characterization, North Weld Landfill Unit 2, Permitting and Development (Swift River 2016b). As reported in the Report of Geotechnical Investigation (Swift River 2016a), the field program encountered clayey silt with fine-grained sand to a typical depth of approximately 15 feet below existing ground surface across the Unit 2 waste disposal footprint. Disturbed bulk samples of this material were collected from within the proposed landfill excavation depth for the development of the Unit 2 subgrade and subjected to laboratory testing to evaluate suitability for use in landfill construction. Five disturbed samples were remolded to 97% maximum dry density and moisture content at 2.5% above optimum to evaluate possible use as cohesive soil liner material. Remolded hydraulic conductivities ranged from 2.8 x 10-7 to 2.5 x 10-8 cmisec, with a geometric average of 1.2 x 10-7 cmisec, suggesting that suitable material is available on site for use in alternative liner system construction. i:115\15388801040M0404 edop fnl decl6\appendix i_alternative liner demonstration\app i ald report 21dec16.docx Golder Associates December 2016 4 1538880 2.0 CONCEPTUAL HYDROGEOLOGIC SITE MODEL 2.1 Geologic Setting The NWLF site is located in an upland area which is covered by as much as 30 feet of Pleistocene -age eolian (wind -deposited) deposits overlying as much as 20 feet of undifferentiated Pleistocene- to Holocene -age glacial outwash alluvium. Within the Unit 2 area of the NWLF site, their combined thickness ranges from between 17 and 45 feet. Consistent with the lithology characterized prior to the development of Unit 1 to the south (ATEC 1993), the eolian deposits generally consist of clayey silt and very fine to fine-grained silty sand and range from 7 to 20 feet in thickness within the Unit 2 waste disposal footprint. The underlying glacial outwash alluvium consists of interbedded coarser -grained sand and fine gravel with varying amounts of silt and clay and range from less than 10 to approximately 25 feet in thickness. Directly beneath the glacial outwash deposits is the weathered Laramie Formation, characterized as a mixture of claystone, siltstone, fine-grained sandstone, and shale interstratified with laterally discontinuous lignite. The Laramie Formation is present beneath the entire NWLF site. Within the proposed Unit 2 waste disposal footprint, the Laramie Formation was encountered at depths ranging from 17 to 45 feet below ground surface and measured up to 30 feet in thickness. Conformably underlying the Laramie Formation is approximately 200 feet of the Fox Hills Sandstone, generally consisting of interbedded layers of fine-grained sandstone, siltstone, and shale (Swift River 2016b). A simplified representative geologic profile of the Unit 2 waste disposal footprint was developed for the purposes of modelling as discussed in Section 4.2.4 of this ALF. 2.2 Hydrogeologic Setting As reported in the Report of Hydrogeological Characterization (Swift River 20►16b) and consistent with groundwater conditions monitored around Unit 1, groundwater in the vicinity of the Unit 2 waste disposal occurs within the following formations, listed from shallowest to deepest: ■ Alluvium/Laramie Formation: Discontinuous saturated alluvial deposits of gravelly sands and sandstones were encountered in three monitoring wells at the contact between the alluvium and the Laramie Formation between 38 feet and 48 feet below top of well casing. These zones are present along only the eastern boundary of the Unit 1 and Unit 2 waste disposal areas. These zones are assumed to be unconfined. ■ Laramie Formation: Localized, discontinuous water -bearing sands and lignite seams within the Laramie formation were encountered in two monitoring wells along the eastern Unit 2 boundary between 46 feet and 56 feet below top of well casing. These isolated zones appear to be confined and not hydraulically connected to the deeper saturated aquifer. ■ Fox Hills Sandstone: The regional zone of saturation within the Fox Hills Sandstone was encountered across both Unit 1 and Unit 2 areas of the NW LF site, with water levels that i:115\1538880104010404 edop fnl decl6\appendix i_alternative liner demonstration\app i ald report 21dec16.docx Golder Associates December 2016 5 1538880 can be correlated and mapped together across the site. This zone appears to be confined beneath all or most of the NWLF site and represents the uppermost continuous saturated zone. Groundwater flow within this zone is south -southwestward, consistent with conditions routinely monitored at Unit 1. Stabilized water levels within the Unit 2 area of the NWLF site ranged from 50 feet to 128 feet below top of well casing. The discontinuous water -bearing zones encountered at the contact between the alluvium and the Laramie Formation and within the Laramie Formation itself along the western boundary of Unit 2 are isolated, perched zones and are not continuous across the NWLF site. The POC for this demonstration (i.e., the vertical surface that is not more than 150 meters from the waste management unit boundary) occurs within the saturated and laterally continuous Fox Hills Sandstone (uppermost aquifer). Since the direction of groundwater flow within the Fox Hills Sandstone is south -southwestward, the POC was defined along the southern and western boundaries of the Unit 2 disposal footprint, as shown in Figure 2. This POC is consistent with the POC previously defined for Unit 1 in the North Weld Sanitary Landfill Alternative Design Evaluation (Rust 1993). The POC is discussed in greater detail in Section 4.2.5 of this ALF. i:115\1538880104010404 edop fnl decl6\appendix i_alternative liner demonstration\app i ald report 21dec16.docx Golder Associates December 2016 6 1538880 3.0 LEACHATE SOURCE ANALYSIS The HELP Model was used for the leachate source analysis to estimate the maximum leachate impingement rate through the alternative liner system within Unit 2. 3.1 Operational Scenarios A HELP model analysis was performed to estimate leachate generation rates within Unit 2, assuming various waste depths and cover configurations. The analysis was initially performed for the following operational conditions, assumed to represent the most critical typical operational scenarios anticipated to occur throughout the life of the landfill from a leachate-generation standpoint: ■ Scenario 1: 6 feet of waste with daily cover (1 year weather generation); ■ Scenario 2: 70 feet of waste with daily cover (1 year of weather generation); ■ Scenario 3: 70 feet of waste with intermediate cover (10 years of weather generation); and ■ Scenario 4: 154 feet of waste with final cover (30 years of weather generation representative of post -closure period). The results of the initial analysis indicated that the operational conditions modeled under both Scenarios 1 and 2 result in very similar leachate impingement rates through the alternative liner system. For the purposes of this ALF, the maximum impingement rate from Scenario 2 was used as the input parameter to the MULTIMED model discussed in Section 4.0. Since the HELP model is limited to a quasi -two-dimensional input model of a single geometrically defined waste mass, the operational input parameters for Scenario 2 (i.e., the waste height, slope length) were further varied to evaluate the sensitivity of the results to changes in these parameters. The results of the HELP model are discussed in Section 3.3 of this ALF. 3.2 HELP Input Parameters 3.2.1 Meteorological Data Meteorological data for the Landfill site was synthetically generated using the WGEN synthetic weather generator developed by the USDA Agricultural Research Service (ARS) and built into the HELP model. Statistical characteristics for synthetic weather data generation were adopted from Cheyenne, Wyoming, the nearest city to the site with published values in the program's default database. Daily solar radiation and evapotranspiration data were synthetically generated based on the latitude for Ault, Colorado (40.59° N). 3.2.2 General Design Inputs The following is a list of the general input parameters used for the HELP analysis: ■ The length and slope of the landfill floor was modeled at 845 feet and 2.64%, based on the maximum leachate flow path length within the leachate collection drainage layer and considering the maximum estimated consolidation of foundation soils; ■ The compacted cohesive soil liner consists of 24 inches of on -site low -permeability soil; i:115\15388801040M0404 edop fnl decl6\appendix i_alternative liner demonstration\app i ald report 21dec16.docx Golder Associates December 2016 7 1538880 ■ The granular leachate collection drainage layer consists of six -inches of coarse -grained sand; ■ Daily and intermediate cover soils consist of on -site eolian deposit material (sandy clay loam) encountered within the proposed excavation depth for the development of the Unit 2 subgrade; ■ 100% of the waste area was allowed to have runoff, with an SCS runoff curve number (CN) of 85; ■ The waste surface was assumed to be bare ground (i.e., Leaf Area Index of 0); and ■ The evaporative zone depth was limited to the thickness of the cover material modeled. 3.2.3 HELP Material Layers Material properties were referenced site -specific geotechnical data from the Report of Geotechnical Investigation (Swift River 2016a) and correlated to default HELP model soil textures, with user -defined properties input to reflect specific material requirements, where appropriate. Material properties used in the HELP analysis are listed below from bottom of the alternative liner system to top of the daily, intermediate, or final cover: ■ The 24 -inch -thick compacted cohesive soil liner (all scenarios) was modeled as a barrier soil liner, with user -defined soil properties referenced from recent NWLF CQA data from Unit 1 cell construction projects and a hydraulic conductivity of 1 x 10-7 cm/sec. ■ The granular leachate collection drainage layer (all scenarios) was modeled as a lateral drainage layer, HELP default Soil Type 1 (SP in USCS, CoS in USDA), with a hydraulic conductivity of 1 x 10-2 cm/sec. ■ The waste mass (all scenarios, varying thickness) was modeled as a vertical percolation layer, HELP default Soil Type 18 (municipal solid waste), with a hydraulic conductivity of 1 x 10-3 cm/sec. ■ Daily and intermediate cover (all scenarios) were modeled as a vertical percolation layer with user -defined soil properties from site -specific laboratory test data (Swift River 2016a) and a default hydraulic conductivity of 1.9 x 10-4 cm/sec for HELP default Soil Type 10 (SC in USCS, SCL in USDA). ■ The 30 -inch -thick water balance final cover (Scenario 4) was modeled as a vertical percolation layer with user -defined soil properties from site -specific laboratory test data (Swift River 2016a) and a default hydraulic conductivity of 1.9 x 10-4 cm/sec for HELP default Soil Type 10 (SC in USCS, SCL in USDA). 3.3 Results As previously discussed in Section 3.1 of this Alterative Liner Demonstration and summarized in Table 1 below, the operational conditions modeled under both Scenarios 1 and 2 result in very similar critical leachate generation and impingement rates through the alternative liner system. This observation indicates that leachate generation at the NWLF site is primarily driven by the moisture content of the waste and limited to the first lift of waste placed. Subsequent waste lifts do not contribute to additional generation of leachate, primarily due to storage capacity and evaporation of precipitation within the cover soils. For example, the NWLF site has an average annual precipitation of approximately 14 inches (NOAA 2016b). The climate's demand for water, referred to as potential evapotranspiration, is calculated as approximately 54 inches i:115\153888th040040404 edop fnl decl6\appendix i_alternative liner demonstration\app i ald report 21dec16.docx Golder Associates December 2016 8 1538880 (NOAA 2016a and NMSU 1996), or 390% more than the actual supply of water (i.e., precipitation). This behavior is also consistent with site -specific observations from throughout the operational life of Unit 1 at NWLF, where generation of leachate has been observed to significantly decrease once the first lift of waste is placed in the active phase. Table 1: Initial Leachate Generation Analysis HELP Model Results Scenario Waste and Cover Configuration Model Duration (yrs) Peak Daily Head on Liner (inches) Average Annual Impingement (in/yr) Liner 1 6 feet of waste with daily cover - 1 4.28 0.9720 2 70 feet of waste with daily cover 1 4.28 0.9739 3 . 70 feet of waste with intermediate cover 10 8.10 0.4306 4 154 feet of waste with final cover 30 8.06 0.0826 In order to conservatively identify the maximum leachate impingement rate under the operational conditions represented by Scenario 2, a sensitivity analysis was performed to evaluate the sensitivity of the HELP model results to the operational input parameters (i.e., the waste height, slope length). The results of the sensitivity analysis indicated that the base operational conditions modeled as Operational Scenario 2 (i.e., slope length of 845 feet and floor slope of 2.64%) result in the most critical (i.e., maximum) leachate impingement rate of 0.9739 inches per year. This rate was used as the source infiltration rate input parameter to the MU LTI MED model discussed in Section 4.2.2 of this ALF. The HELP model output report from Operational Scenario 2 is provided in Appendix A. i:115\15388801040M0404 edop fnl decl6\appendix i_alternative liner demonstration\app i ald report 21dec16.docx Golder Associates December 2016 9 1538880 4.0 EVALUATION OF IMPACT ON GROUNDWATER QUALITY The MULTIMED model was used to demonstrate that predicted concentrations of selected leachate chemical constituents will not exceed the MCLs listed in Table 1 of 40 CFR 258.4 at the Unit 2 POC. 4.1 Dilution Factors (DFs) DFs were used to demonstrate the level of groundwater protection the alternative liner system will provide at the POC. DFs are also commonly referred to as Dilution Attenuation Factors (DAFs); however, as discussed in Section 4.2.3, attenuation factors (i.e., hydrolysis, decay, and adsorption) were neglected in this demonstration to add a significant conservative element to the modeling. Therefore, DAFs are hereinafter referred to as DFs throughout this ALF. Based on the MCLs and site -specific leachate concentrations, minimum DFs that must be achieved to meet the regulatory requirements were calculated. The DF is defined as the initial concentration of a contaminant within the leachate, Co, divided by the concentration at the point of compliance, Cp. Therefore, if the initial concentration Co is set to a unit concentration of 1, the MULTIMED model will calculate a value of C p for which the inverse is the DF. This DF can then be directly compared with the highest required DF to demonstrate that listed MCLs as shown in Table 2 below are not exceeded. Background concentrations from Unit 1 groundwater monitoring wells completed within the Fox Hills Sandstone are provided for reference but were not considered in DF calculations (i.e., natural background for the modeled parameters were assumed to be non -detect within the Fox Hills Sandstone). This methodology has been adopted for this analysis. Site -specific leachate concentration data from Unit 1 was reviewed from between 1995 and 2016. Maximum constituent concentrations from leachate samples collected during that period for which MCLs have been established are listed in Table 2. Also shown in Table 2 are the calculated required minimum DFs to ensure MCLs are not exceeded at the POC, which range from 1 to 14 for those constituents where site -specific data was available. For those constituents that have not been tested but for which an MCL is defined, a DF of 100 was assumed. A DF of 1 or less indicates that no dilution or attenuation is needed (i.e., the concentration of that constituent within the leachate is below the MCL). i:115\15388801040M0404 edop fnl decl6\appendix i_alternative liner demonstration\app i ald report 21dec16.docx Golder Associates December 2016 10 1538880 Table 2: MCLs, Leachate Input Concentrations, and IMF Requirements Constituent MCL listed in 40 CFR 258.4 (mg/L) C Maximum Site Leachate Concentration (mg/L) -specific Background Concentration {1}t2 zit (mg/L) minimum Required BF Arsenic 0.05 0.0549 < 0.0100 - 0.0132 2 Barium 1.0 3.37 < 0.200 0.2'25 4 - Benzene 0.005 0.03 < 0.005 6 Cadmium 0.01 0.009 < 0.0050 - 0.0064 < 1 Carbon tetrachloride 0.005 < 0.005 < 0.010 < 1 (hexavalent) Chromium 0.05 0.16 (total Cr) < 0.010 (total - 0.0780 Cr) 4 2,4-Dichlorophenoxy acetic acid 0.1 -- n/a 100 1,4-Dichlorobenzene 0.075 < 1 - < 0.005 14 1,2-Dichloroethane 0.005 0.062 < 0.005 13 1,1 -Dish loroethyl en a 0.007 0.049 < 0.005 7 Endrin 0.0002 -- n/a 100 Fluoride 4 -- n/a 100 Lindane 0.004 -- n/a 100 Lead 0.05 0.113 < 0.0050 - 0.0369 3 Mercury 0.002 0.00056 n/a 3 Methoxychlor Ior 0.1 -- n/a 100 Nitrate 10 < 1 < 0.5 < 1 Selenium 0.01 0.014 < 0.0050 - 0.0082 2 Silver 0.05 < 0.125 < 0.0250 3 Toxaphene 0.005 -- n/a 100 1,1,1-Trichloroethane 0.2 0.039 n/a < 1 Trichloroethylene 0.005 0.016 < 0.005 4 2,4,5-Trichlorophenoxy acetic acid 0.01 -- n/a 100 Vinyl chloride 0.002 0.012 < 0.010 6 Notes: 1). Where site -specific data exists from Unit 1 detection monitoring program, background concentration range reported as laboratory reporting limit to highest detection to date. 2). No volatile organic compounds (VOCs) have been detected to date in Unit 1 detection monitoring program. For VOCs, background concentration range reported as less than practical quantitation limits (PQL) provided in 6 CCR 1007-2, Part I, Appendix ll for Assessment Monitoring. 3). n/a — Not analyzed in NWLF detection monitoring program. i:i5\153888010400\0404 edop Inl dec161appendix i_alternative liner demonstration\app i ald report 21dec16.docx Golder Associates December 2016 11 1538880 4.2 MULTIMED Input Parameters The following subsections describe the input parameters that were used to demonstrate that a suitable DF will be obtained using the proposed alternative liner system design. 421 General Parameters The following is a list of the general model parameters used for the MULTIMED analysis: ■ The MULTIMED model was run using a Subtitle D Landfill -type evaluation. Under the Subtitle D type, certain parameter values are preset to appropriate default values; such preset parameters are noted herein. The use of the Subtitle D type simulation implies that the following model assumptions were also made: • The contaminant pulse is continuous and constant over time; • The receptor well (POC) is located downgradient in the center of the contaminant plume at the top of the aquifer; • No attenuation of contaminants occurs in the leachate during flow through the liner system; and • The primary mode of attenuation for contaminants entering the subsurface is physical dispersion and dilution in the receiving aquifer. ■ To compensate for uncertainty in input parameters, conservative assumptions were applied in the MULTIMED analysis. These assumptions are noted herein. ■ The concentration of contaminant was treated as a Gaussian source, enriched along the centerline and tapering to each side of the plume. ■ Additional transient simulations were conducted to more accurately simulate operational site life conditions and evaluate modeled leachate constituent concentrations at the P00 through the post -closure care period. 422 Source Parameters 4.2.2.1 Source Geometry For the steady-state MULTIMED model, the maximum area of alternative liner system that is expected to be subjected to leachate head was conservatively estimated to be 2,025 square feet. This area represents the total footprint of a temporary leachate collection sump within Unit 2 and exceeds the total area of the two permanent leachate collection sumps. For the transient MULTIMED models, the source area was modeled as the total surface area of the two permeant leachate collection sumps, 1,368 square feet. 4.2.2.2 Source Infiltration Rate The HELP model was used to evaluate leachate impingement rates through the alternative liner system throughout the operational life of Unit 2. As discussed in Section 3.3 of this ALF, the operational scenario that resulted in the maximum impingement rate was 70 feet of waste with daily cover. The impingement rate associated with this operational condition was 0.9739 inches per year (2.474 x 10-2 m/yr). i:115\1538880104010404 edop fnl decl6\appendix i_alternative liner demonstration\app i ald report 21dec16.docx Golder Associates December 2016 12 1538880 4.2.2.3 Outside Recharge Rate The outside recharge rate is defined as the rate of infiltration into the aquifer resulting from natural precipitation downgradient and outside of the waste disposal limit. For conservatism, the outside recharge rate was neglected (i.e., 0 m/yr); in this way, no dilution of the contaminant plume occurs in the saturated zone from outside infiltration. 4.2.2.4 Initial Leachate Concentration The initial leachate concentration was set to a unit concentration of one milligram per liter (mg/L) in order to directly derive the DAF. The DAF is defined as the initial leachate concentration divided by the predicted concentration at the POC. 4.2.2.5 Source Duration and Decay Constant The source duration and decay constant parameters are not applicable to the Subtitle D -type evaluation. As discussed in Section 4.2.1 of this ALF, the Subtitle D evaluation assumes that the contaminant pulse is continuous and constant over time. For transient simulations, the source duration was set to 35 years to conservatively simulate a constant leachate source (strength and volume) for the approximate operational life of the facility. 4.2.2.6 Initial Spread of Source The initial spread of source parameter is defined as the standard deviation of the aquifer source plane geometry parameter and was auto -derived from the Gaussian distribution input parameter. 4.22 Chemical Parameters Chemical input parameters are related to chemical reaction (hydrolysis), biodegradation (decay), and chemical adsorption processes. For conservatism in this MULTIMED analysis, chemical processes were neglected in the transport mechanism. Therefore, all chemical parameters were set to 0. 4.2.4 Hydrogeologic c Properties Subsurface data collected from the geotechnical and hydrogeologic site characterization of the Unit 2 area of the NW LF site (Swift River 2016) served as the basis of the MULTIM ED analysis. Temporary well TW-10, drilled to a depth of 98.5 feet below ground surface and completed within the Fox Hills Sandstone, was determined to be the most conservative representation of the general subsurface profile across the Unit 2 waste disposal footprint due to the well's proximity to the permanent leachate collection sumps and considering the Fox Hills Sandstone is a regionally extensive water -bearing zone that is laterally continuous across the NWLF site. The base grades of the permanent leachate collection sumps represent the minimum vertical separation between the base of the liner system and the uppermost continuous saturated zone, the Fox Hills Sandstone. For the purposes of the steady-state MULTIMED model, the soil profile at TW-10 was i:115\1538880104010404 edop fnl decl6\appendix i_alternative liner demonstration\app i ald report 21dec16.docx Golder Associates December 2016 13 1538880 conservatively assumed to exist at the western limit of waste in Phase 4, which represents the minimum distance from the limit of waste to the nearest theoretical Unit 2 ROC groundwater monitoring well. 4.2.4A Unsaturated Zone Flow and Transport Properties Flow and transport input properties for the MULTIMED analysis are presented in Table 3. Where possible, input properties were referenced from site -specific data. Where site -specific data was not available, input properties were referenced from published literature. Table 3: MULTIMED Input Parameters — Unsaturated Zone Flow and Transport Properties Vadose Zone Flow and Transport I Unit I Value I Reference Layer 1 — Silty Sand Flow Layer Thickness m 5 TW-10 (Swift River 2016b) Flow Layer Number -- 1 -- Saturated Hydraulic Conductivity (ksat) cm/sec 2.9E-03 • Site-specific NW (Swift E-12) lab data and slug River 2016a (NWE-7, test and data 2016b) Saturated Hydraulic Conductivity YNW (ksat) cm/hr 10.44 Site -specific E-12 lab ) (Swift data River (NWE-7, 2016a) Effective Porosity01, -- 0.437 HELP Model NWE-03 (Loamy Sand - NWE- Air Entry Pressure Head m 0 -- Layer 1 Silty Sand (Cont.) — Residual Water Content -- 0.057 Carsel and Parrish, 1988 van Genuchten Alpha (a) 1/cm 0.124 Carsel and Parrish, 1988 van Genuchten Beta (3) - 2.28 Carsel and Parrish, 1988 Bulk Density pcf 90.7 Site NW -specific E-12(Swift lab data River (NWE-7, 2016a) Bulk Density glom 3 1.45 Site NW -specific E-12) lab data ((Swift River (NWE-7, 2016a) Layer 2 — Stiff Clay Flow Layer Thickness m 6.5 TW-10 (Swift River 2016b) Flow Layer Number -- 2 -- Saturated Hydraulic Conductivity (ksat) cm/sec 6.4E-05 HELP Model (Material 11 - CL) Saturated Hydraulic Conductivity (ksat) cm/hr 0.2304 HELP Model (Material 11 - CL) Effective Porosity (n) -- 0.464 HELP Model (Material 11 - CL) Air Entry Pressure Head m 0 i -- Residual Water Content -- 0.068 Carsel and Parrish, 1988 van Genuchten Alpha (a) 1/cm 0.008 Carsel and Parrish, 1988 van Genuchten Beta (13) - 1.09 Carsel and Parrish, 1988 i:115\153888th04010404 edop fnl decl6\appendix i_aiternative liner demonstration\app i ald report 21dec16.docx Golder Associates December 2016 14 1538880 Vadose Zone Flow and Transport Unit Value Reference Bulk Density pcf 110 NAVFAC 7.01, 1986 Bulk Density a g/cm 3 1.60 i NAVFAC 7.01, 1986 Layer 3 — Claystone Flow Layer Thickness m 3.5 TW-10 (Swift River 2016b) Flow Layer Number -- 3 -- Saturated Hydraulic Conductivity (ksat) cm/sec 8.60E-07 Lu, Kaya, and Godt, 2014 Saturated Hydraulic Conductivity (ksat) cm/hr 0.0031 Lu, Kaya, and Godt, 2014 Effective Porosity (n) -- 0.55 Lu, Kaya, and Godt, 2014 Air Entry Pressure Head m 0 -- Residual Water Content -- 0.01 Lu, Kaya, and Godt, 2014 van Genuchten Alpha (a) 1/cm 0.02 Lu, Kaya, and Godt, 2014 van Genuchten Beta 03) - 1.40 Lu, Kaya, and Godt, 2014 Bulk Censit y g /cm3 2.19 Manger, (Cretaceous-Adaville) 1963 Layer 4 — Dense Sand with Silt Flow Layer Thickness m 2 TW-8 (Swift River 2016b) Flow Layer Number -- 4 -- Saturated Hydraulic Conductivity (ksat) cm/sec 1.2E-03 Carsel and Parrish, 1988 Layer 4 Dense Sand with Silt (Cont.) — Saturated Hydraulic Conductivity (ksat) cm/hr 4.420 Carsel and Parrish, 1988 Effective Porosity (n) -- i 0.189 Carsel and Parrish, 1988 Air Entry Pressure Heada m 0 -- Residual Water Contenta -- 0.065 Carsel and Parrish, 1988 van Genuchten Alpha (a) licm 0.075 I Carsel and Parrish, 1988 van Genuchten Beta ()a a - I 1.89 Carsel and Parrish, 1988 Bulk Densitya pcf i 120 NAVFAC 7.01, 1986 Bulk Density g/cm 3 1.92 NAVFAC 7.01, 1986 Additional input parameter assumptions included: • In the absence of published air entry pressure head data, air entry pressure head of all strata was conservatively set to 0 to be representative of coarse soil materials; • The longitudinal dispersivity parameter was auto -derived from the depth of the unsaturated zone; • The percent organic matter and biological decay coefficients were conservatively set to 0 since chemical reaction, biodegradation, or chemical adsorption processes were neglected in the analysis. i:115\153888th040040404 edop fnl decl6\appendix i_alternative liner demonstration\app i ald report 21dec16.docx Golder Associates December 2016 15 1538880 4.2.4.2 Saturated Zone Properties Aquifer -specific input properties for the MULTIMED analysis are presented in Table 4. Table 4: MULTIMED Input Parameters — Saturated Zone Properties Saturated Zone I Unit I Value I Reference Aquifer Estimated Aquifer Thickness m 12 TW-10 (Swift River 2016b) Effective Porosity (n) -- 0.32 Robson, 1987 Bulk Density glcm3 2.25 s Robson, 1987 (Cretaceous) Saturated Hydraulic ra u l i c Conductivity y (ksat) i cm/sec 1.2E-02 Site -specific (Swift slug test data River, 2016b) Saturated Hydraulic Conductivity yy (ksat) mfr 3796 Site (Swift -specific slug River, 2016b) test data Hydraulic Gradient -- 0.003 Site (Swift -specific aquifer data River, 2016b) Aquifer q Temperature p ° C 13.8 Site -specific (Swift aquifer River, 2016b) data A q uiferpH -- 7.66 Site (Swift -specific aquifer River, 2016b) data Additional input parameter assumptions included: • Aquifer temperature, pH, and fraction organic carbon were input based on Swift River sampling. However, these properties are not considered in the MULTIMED analysis as retardation and decay were conservatively neglected. • Aquifer fraction organic carbon was neglected. • Longitudinal, transverse, and vertical dispersivity were auto -derived from the distance to the receptor well. 4.2.5 Point of Compliance (POC) Location As discussed in Section 2.2 of this ALF, the Unit 2 POC was defined as the vertical surface that is not more than 150 meters from the waste management unit boundary along the southern and western boundaries of the Unit 2 waste disposal footprint. This defined POC includes the following existing monitoring wells screened within the Fox Hills Sandstone: • Down -gradient of Unit 1: MW -4, MW -5, MW -9, and MW -10 • Down -gradient of Unit 2: MW -3 and TW-2 For the purposes of the steady-state MULTIMED model, the radial distance of the receptor well (i.e., the POC) from the leachate source was conservatively set to only 34 meters (m), the minimum distance from the nearest theoretical Unit 2 POC groundwater monitoring well to the limit of waste. For i:115\1538880104010404 edop fnl decl6\appendix i_alternative liner demonstration\app i ald report 21dec16.docx Golder Associates December 2016 16 1538880 transient MULTIMED models, the radial distance of the receptor well was more accurately defined as 708 m which represents the distance between the permanent leachate collection sump in Phase 5 and the western limit of waste. The location of this receptor well appropriately considers site -specific flow direction of the Fox Hills Sandstone, the nearest Unit 2 POC groundwater monitoring well located hydraulically downgradient of Unit 2, and the permanent sump leachate source used in the MULTIMED model. 4.2.6 Time Parameters For transient simulations, the source duration was set to 35 years to simulate the approximate operational life of the facility and the MULTIMED model was run for 65 years to approximate the full post -closure period of the facility. DAFs were calculated at five-year increments for the full model duration. 4.3 MULTIMED Model Results 4.3.1 Steady-state Results The steady-state Subtitle D model assumes a continuous source pulse (i.e., impingement rate) through time, thus the leachate source strength and volume never decreases. In addition, it assumes equilibrium between the fluid moving into the system being modeled and the fluid moving out of the system. The steady- state model was also run with all attenuating parameters set to 0, thus maximizing transport capability. These assumptions create a very conservative simulation of actual operations at NWLF. Once the system has reached equilibrium, the predicted leachate concentrations at the Unit 2 POC will be approximately 4.5 x 10-3 of the initial constituent concentration (equivalent to a DF value of 220 and conservatively ignoring attenuation factors). Based on the site -specific leachate data, leachate constituent concentrations at the Unit 2 POC are summarized in Table 5 below. For all leachate constituents with historical site -specific data, the steady-state concentrations at the POC are more than one order of magnitude less than the corresponding MCLs. Background concentrations from Unit 1 detection monitoring of the Fox Hills Sandstone are provided for reference. The output file for the steady-state MULTIMED model is provided in Appendix B-1. Table 5: MULTIMED Steady-state Analysis Results Leachate Constituent Concentrations at Point of Compliance Constituent MCL (mg/L) listed in 40 CFR 258.40 . Background Concentration t1}{2} 3) (mg/L) Concentration at Point Compliance (mg/L) of Minimum Required DF Calculated DF Arsenic 0.05 < 0.0100-0.0132 2.50 x 10-4• 2 274 Barium 1.0 < 0.200-0.225 1.53 x 10-2 4 274 i*15\1538880104010404 edop fnl decl6\appendix i_alternative liner demonstration\app i ald report 21dec16.docx Golder Associates December 2016 17 1538880 Benzene 0.005 < 0.005 1.86 x 10-4 6 274 Cadmium a 0.01 < 0.0050-0.0064 4.09 x 10-s < 1 a 274 Carbon tetrachloride 0.005 < 0.010 < 2.27 x 10-5 <1 274 Chromium (hexavalent) 0.05 < (total 0.010-0.0780 . Cr) 7.27 (total x 10-4' Cr) 4 274 2,4-Dichlorophenoxy acetic acid 0.1 nia -- 100 274 1,4-Dichlorobenzene 0.075 < 0.005 < 4.55 x 10-3 14 274 1,2-Dichloroethane 0.005 < 0.005 2.82 x 10-4 13 274 1,1-Dichloroethylene a 0.007 < 0.005 2.23 x 10-4 a 7 274 Endrin a 0.0002 nia -- 100 a 274 Fluoride 4 nia -- 100 274 Lindane 0.004 a n/a -- 100 274 Lead a 0.05 < 0.0050-0.0369 5.14 x 10-4, a 3 274 Mercury a 0.002 nia 2.55 x 10-6 a 3 274 Methoxychlor for 0.1 a nia -- 100 : 274 Nitrate 10 < 0.5 < 4.55 x 10-3 <1 274 Selenium a 0.01 < 0.0050-0.0082 6.36 x 10-5 2 a 274 Silver a 0.05 < 0.0250 < 5.68 x 10-4 3 274 Toxaphene 0.005 nia -- 100 274 1,1,1-Trichloroethane 0.2 nia 1.77 x 10-4, < 1 274 Trichloroethylene a 0.005 < 0.005 7.27 x 10-5 4 a 274 2,4,5-Trichlorophenoxy acetic acid 0.01 nia -- a 100 274 Vinyl chloride 0.002 < 0.010 5.45 x 10-5 6 274 Notes: 1). Where site -specific data exists from Unit 1 detection monitoring program, background concentration range reported as laboratory reporting limit to highest detection to date. 2). No volatile organic compounds (VOCs) have been detected to date in Unit 1 detection monitoring program. For VOCs, background concentration range reported as less than Practical Quantitation Limits (PQL) provided in 6 CCR 1007-2, Part I, Appendix II for Assessment Monitoring. 3). n/a — Not analyzed in NWLF detection monitoring program. 4.3.2 Transient Results Transient model runs were conducted to more accurately simulate operational site life conditions and evaluate leachate constituent concentrations at the POC through the post -closure period (i.e., 30 years after closure). The input parameters from the steady-state model were used as the initial input for the transient model except the source (i.e., impingement rate) duration, source area, and radial distance to the POC, which were updated to more accurately model operational and groundwater monitoring conditions as discussed in Section 4.2 above. i:115\1538880104010404 edop fnl decl6\appendix i_alternative liner demonstration\app i ald report 21dec16.docx Golder Associates December 2016 18 1538880 The results of the transient analyses are summarized in Table 6, which presents the reciprocal of the DFs (conservatively ignoring attenuation factors) at five-year increments through the operational life of the landfill and post -closure period. These DFs can be compared to the DF reciprocal limit for the critical leachate constituent with the highest DF (1,4-dichlorobenzene, DF reciprocal of 7.1 x 10-2) to evaluate whether any MCL at the POC would be exceeded (i.e., if the modeled concentration of 1,4-dichloribenzene at the POC is below the MCL, all other parameters evaluated in this demonstration will also be below their MCL). The output files for the transient MULTIMED models are provided in Appendix B-2. The transient model data indicates that assuming the maximum impingement rate (i.e., source infiltration rate) conservatively calculated in the HELP model is constant for the full 35 -year operational life of Unit 2, leachate constituents are not predicted to be detected above laboratory reporting limits (i.e., PQLs) at the P0C through the operational life and post -closure period of the facility. Table 6: MULTIMED Transient Analysis Results DF Reciprocal Values at POC Over Unit 2 Operational Life and Post -closure Period Time (yrs) Maximum Reciprocal Limittl DF 2) DF Reciprocal 1 10-2 0 5 0 10 7.8 x 10-26 15 1.3x 10-19 20 7.8 x 10-18 25 5.4x 10-17 30 7.1 1.6x10-16 35 x 3.3 x 10-16 40 5.3 x 10-16 45 7.5 x 10-16 50 9.8 x 10-16 55 1.1 x 10-14 60 1.5 x 10-11 65 2.5 x 10-1° Notes: 1). The DF Reciprocal Limit represents the leachate constituent concentration reduction factor from the initial concentration that results in an MCL exceedance at the POC. 2). Maximum OF Reciprocal Limit is based on leachate constituents with site -specific data; of the leachate constituents routinely analyzed at the NWLF site, 1,4-dichlorobenzene yielded the highest required DF (14). i:115\153888th040040404 edop fnl decl6\appendix i_alternative liner demonstration\app i ald report 21dec16.docx Golder Associates December 2016 19 1538880 5.0 CONCLUSIONS This ALF presents the HELP and MULTIMED modeling performed in support of the alternative liner system proposed for Unit 2 at NWLF. The modeling efforts demonstrate that the alternative liner system proposed for the development of Unit 2 at NWLF reasonably ensures groundwater protection considering expected waste characteristics, site construction, and site setting. The modeling demonstrates that the liner system will provide a level of groundwater protection such that the MCLs listed in Table 1 of 40 CFR 258.40 will not be exceeded at the Unit 2 POC as summarized below: • HELP modeling conservatively identified the maximum impingement rate through the alternative liner system at various waste depths and cover configurations over the life of the facility. The maximum impingement rate used as the input parameter in MULTIMED transport modeling was estimated at 0.9739 inches per year (2.474 x 10-2 m/yr). • Steady-state MULTIMED modelling of leachate transport from the base of the alternative liner system to the POC conservatively estimated a DF reciprocal of 4.5 x 10-3 compared to the maximum required DF reciprocal of 7.1 x 10-2 (for 1,4dichlorobenzene) to ensure MCLs are not exceed at the POC. • The steady-state model conservatively assumes a continuous leachate source infiltration rate (source strength and volume) through time over the full surface area of a temporary leachate collection sump and that equilibrium was reached between the fluid entering the system and the fluid leaving the system. • Additionally, the recharge rate of the aquifer and all potentially attenuating input parameters were set to zero, resulting in very conservative transport model results (i.e., actual DAF is higher than DF calculated in this report). • The radial distance of the receptor well (i.e., the POC) from the leachate source was conservatively set to 34 m, the minimum distance from the theoretical POC groundwater monitoring well to the limit of waste. • The general subsurface profile across the Unit 2 waste disposal footprint was modeled based on the conditions encountered at temporary well Tw-10, which represents the minimum vertical separation from the alternative liners system to the uppermost continuous saturated zone (Fox Hills Sandstone). For the purposes of the steady-state model, this profile was assumed to exist at the western limit of waste and considers the Fox Hills Sandstone as a regionally extensive water -bearing zone that is laterally continuous across the NWLF site. • Transient MULTIMED modelling of leachate transport under more representative operational site conditions estimated the following: • Assuming the maximum impingement rate calculated in the HELP Model is constant for the full 35 -year operational life of Unit 2, leachate constituents are not predicted to be detected above laboratory reporting limits (i.e., PQLs) at the Unit 2 POC through the operational life and post -closure period of the facility. i*15\1538880104010404 edop fnl decl6\appendix i_alternative liner demonstration\app i ald report 21dec16.docx Golder Associates December 2016 20 1538880 6.0 REFERENCES Allison Geoscience Consultants (AGC). 2005. Multimed for Windows, Version 1.51. ATEC Associates, Inc. (ATEC). 1993. Hydrogeologic Site Characterization Report, North Weld Sanitary Landfill, Weld County, Colorado. Carsel, R.F., and R.S. Parrish. 1988. Developing joint probability distributions of soil water retention characteristics. Water Resour. Res. 24(5) :755-769. Code of Federal Regulations (CFR). 2015. Title 40 — Protection of Environment. CHAPTER I ENVIRONMENTAL PROTECTION AGENCY. SUBCHAPTER I - SOLID WASTES. PART 258 CRITERIA FOR MUNICIPAL SOLID WASTE LANDFILLS. Subpart D — Design Criteria. July 1. Colorado Department of Public Health and Environment (CDPHE). 2015. Hazardous Materials and Waste Management Division. Part 1 — Regulations Pertaining to Solid Waste Disposal Sites and Facilities, 6 CCR 1007-2. Amended November 17. Golder Associates Inc. (Golder). 2016. Construction Quality Assurance (CQA) Plan for North Weld Landfill; Weld County, Colorado. Revision 8. July. Lu, N., M. Kaya, and J. Godt. 2014. Interrelations among the Soil —Water Retention, Hydraulic Conductivity, and Suction -Stress Characteristic Curves. J. Geotech. Geoenviron. Eng. 10.1061 /(AS C E) GT .1943-5606.00010 65, 04014007. Manger, C.E. 1963. Porosity and Bulk Density of Sedimentary Rocks. Geological Survey Bulletin 1144-E. Prepared partly on behalf of the United States Atomic Energy Commission. N ational Centers for Environmental Information, National Oceanic and Atmospheric Administration (NOAA). 2016a. Climate Data Online. Fort Collins, CO 4 E Station. Available online: https://www.ncdc.noaa.gov/cdo-web/ (accessed October 5, 2016 by Dwyer Engineering, LLC). N OAA. 2016b. Climate Data Online. Greeley U NC Station. Available online: https://www.ncdc.noaa.gov/cdo-web/ (accessed August 16, 2016). N aval Facilities Engineering Command (NAVFAC). 1986. Design Manual 7.01, Soil Mechanics. Revalidated September 1. N ew Mexico State University (NMSU). 1996. Potential and Actual Evapotranspiration Wizard Using Samani's Equation Java Version. Last updated May 29, 2003. Available online: http://hydrologyl .nmsu.edu/chile/samani.html (accessed October 5, 2016 by Dwyer Engineering, LLC). Robson, S.G. 1987. Bedrock Aquifers in the Denver Basin, Colorado — A Quantitative Water -Resources Appraisal. United States Geological Survey Professional Paper 1257. Rust Environment & Infrastructure, Inc. (Rust). 1993. North Weld Sanitary Landfill Alternative Design Evaluation. April 14. Rust. 1997. Updated Design and Operations Plan for the North Weld Sanitary Landfill. November. Schroeder, P.R., T.S. Dozier, P.A. Zappi, B.M. McEnroe, J.W. Sjostrom, and R.L. Peyton. 1994. The Hydrologic Evaluation of Landfill Performance (HELP) Model: Engineering documentation for version 3. Washington, DC: United States Environmental Protection Agency Office of Research and Development. i:115\153888th040040404 edop fnl decl6\appendix i_alternative liner demonstration\app i ald report 21dec16.docx Golder Associates December 2016 21 1538880 Swift River Environmental Services, LLC (Swift River). 2016a. Report of Geotechnical Investigation, North Weld Landfill Unit 2, Permitting and Development. December. Swift River. 2016b. Hydrogeologic rog eo log is characterization of North Weld Landfill Unit 2, Permitting and Development. December. United States Army Corps of Engineers (USAGE). 1997. Hydrologic Evaluation of Landfill Performance (HELP) Model, Version 3.07. Waterways Experiment Station for USEPA Risk Reduction Engineering Laboratory. November 1. i*15\1538880104010404 edop fnl decl6\appendix i_alternative liner demonstration\app i ald report 21dec16.docx Golder Associates FIGURE Last Edited By: alebrown Date: 2016-11-18 Tirne:10:25:31 AM Printed By: ALEBrown Date: 2016-11-18 Time:14:25:57 AM Path: Ale nver.Bolder.gcs‘acad''i15'.183t•88G+z,ROD LK)TION'E - Figures'• File Name; 1 538n8UBQU4.dwg PROJECT NORTH WELD LANDFILL, UNIT 2 SIDE DEVELOPMENT PLANS WELD COUNTY, COLORADO TITLE ALTERNATIVE LINER SYSTEM DETAIL IF THIS MEASUREMENT DOES NOT MATCH WHAT IS SHOWN, THE SHEET SIZE HAS BEEN MODIFIED FROM: ANSI A CLIE\IT WASTE MANAGEMENT DISPOSAL SERVICES OF COLORADO: INC. CONSUl l 1'JT Y'YYY-1.41,..1-DO 1 F31C; -•JF 1: PREPARE) REVIEWED APPROVLL? 2015-11-15 ALL3 ALL) JAR MFM EX SING TOPOGRAPHY (SEE NOTE it 5284— PROPOSED LINEN SUI3GNADE --- PROPERTY BOUNDARY (SEE NOTE 4) - USR 527 BOUNDARY LKISIINGLail I Cl WAS IL(Uhl l 1:1 X — EXIST NG FENCE Gd POINT OF COMPLIANCE EXIg-IUC MCAIITf.RINF; WELL L& ATIC;N TEMPORARY WELL LOCATION .iSEE NOTE FXISTIMG CAS P -OAF I (CATION NOTES 1. EXIS I INS I OPC;{31iAIsI IV is A COMPUSI I E OI- AEHOME I RIC INC. PI lO I O iRAPI IY DA I ED JANUARY 20, 2012 AND MILLER CREEK AER AL MAPPINU Fl IOTOSNAPI IY DATED FFRRLARY 71, 2016. EXISTING CONTOUR INTERVAL IS 2 FEET BASED ON NAVD88 ELEVAT DINS. 3. COORDINATE SYSTEM IS IN NAD2F STATE PLANE COLORADO NORTH. 0 125 2b0 1" = 250' FEET PROJECT NORTH WELD LANDFILL, UNIT 2 SITE DEVELOPMENT PLANS WELD COUNTY, COLORADO TITLE POINT OF COMPLIANCE PI<O.JLC I I'!O 1538880 C ONTP.OI IRLk A FIfIJRF 2 I. Rr,IrtR t:RF.^.'VP MATH -',H' IR?i.^7i.h. THF%HFFT.^'I"F FA?. RE:1'clfli=lFPi F5.:t: filRI Pr APPENDIX A HELP MODEL OUTPUT T * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * THICKNESS POROSITY FIELD CAPACITY WILTING POINT INITIAL SOIL WATER CONTENT EFFECTIVE SAT_ HYD. COND. * * * * * * * * * * * * ** * * ** HYDROLOGIC EVALUATION OF LANDFILL PERFORMANCE HELP MODEL VERSION 3.07 (1 NOVEMBER 1997) DEVELOPED BY ENVIRONMENTAL LABORATORY USAE WATERWAYS EXPERIMENT STATION FOR USEPA RISK REDUCTION ENGINEERING LABORATORY ** * * * * * * ** * * ** * * ** * ***************************************************************************** * ***************************************************************************** PRECIPITATION DATA FILE: TEMPERATURE DATA FILE: SOLAR RADIATION DATA FILE: EVAPOTRANSPIRATION DATA: SOIL AND DESIGN DATA FILE: OUTPUT DATA FILE: TIME: 11:43 C:\NWPREC1.D4 C:\NWTEMPl.D7 C:\NWRAD1.D13 C:\NWEVAP.Dll C:\NWSD_2.D10 C:\NW_ \NW^OUT 2.OU T DATE: 11/16/2016 * ***************************************************************************** TITLE: NORTH WELD LANDFILL SCENARIO 2: 70'WASTE WITH DAILY COVER * ***************************************************************************** NOTE: INITIAL MOISTURE CONTENT OF THE LAYERS AND SNOW WATER WERE COMPUTED AS NEARLY STEADY-STATE VALUES BY THE PROGRAM. LAYER 1 TYPE 1 - VERTICAL PERCOLATION LAYER MATERIAL TEXTURE NUMBER 0 6.00 INCHES 0.3930 VOL/VOL 0.2990 VOL/VOL 0.1330 VOL/VOL 0.1839 VOL/VOL 0.1.19999997000E-03 CM/SEC LAYER THICKNESS P OROSITY FIELD CAPACITY WILTING POINT INITIAL SOIL WATER CONTENT EFFECTIVE SAT. HYD. COND. TYPE 1 - VERTICAL PERCOLATION LAYER MATERIAL TEXTURE NUMBER 18 THICKNESS P OROSITY FIELD CAPACITY W ILTING POINT INITIAL SOIL WATER CONTENT EFFECTIVE SAT. HYD. COND. 840.00 INCHES 0.6710 VOL/VOL 0.2920 VOL/VOL 0.0770 VOL/VOL 0.2920 VOL/VOL 0.100000005000E-02 CM/SEC LAYER 3 TYPE 2 - LATERAL DRAINAGE LAYER MATERIAL TEXTURE THICKNESS P OROSITY FIELD CAPACITY WILTING POINT INITIAL SOIL WATER CONTENT EFFECTIVE SAT. HYD. COND. SLOPE DRAINAGE LENGTH NUMBER 1 6.00 INCHES 0.4170 VOL/VOL 0.0450 VOL/VOL 0.0180 VOL/VOL 0.0717 VOL/VOL 0.999999978000E-02 2.64 PERCENT 845.0 FEET LAYER 4 TYPE 3 - BARRIER SOIL LINER MATERIAL TEXTURE NUMBER 0 24.00 INCHES 0.4450 VOL/VOL 0.3930 VOL/VOL 0.2770 VOL/VOL 0.4450 VOL/VOL 0.100000001000E-06 CM/SEC CM/SEC GENERAL DESIGN AND EVAPORATIVE ZONE DATA NOTE: SCS RUNOFF CURVE NUMBER WAS USER -SPECIFIED. SCS RUNOFF CURVE NUMBER FRACTION OF AREA ALLOWING RUNOFF AREA PROJECTED ON HORIZONTAL PLANE EVAPORATIVE ZONE DEPTH INITIAL WATER IN EVAPORATIVE ZONE UPPER LIMIT OF EVAPORATIVE STORAGE LOWER LIMIT OF EVAPORATIVE STORAGE INITIAL SNOW WATER INITIAL WATER IN LAYER MATERIALS 85.00 100.0 1.000 6.0 1.103 2.358 0.798 0.000 257.494 PERCENT ACRES INCHES INCHES INCHES INCHES INCHES INCHES TOTAL INITIAL WATER TOTAL SUBSURFACE INFLOW 257.494 INCHES 0.00 INCHES/YEAR EVAPOTRANSPIRATION AND WEATHER DATA NOTE: EVAPOTRANSPIRATION DATA WAS OBTAINED FROM CHEYENNE WYOMING STATION LATITUDE MAXIMUM LEAF AREA INDEX START OF GROWING SEASON (JULIAN DATE) END OF GROWING SEASON (JULIAN DATE) EVAPORATIVE ZONE DEPTH AVERAGE ANNUAL WIND SPEED AVERAGE 1ST QUARTER RELATIVE HUMIDITY AVERAGE 2ND QUARTER RELATIVE HUMIDITY AVERAGE 3RD QUARTER RELATIVE HUMIDITY AVERAGE 4TH QUARTER RELATIVE HUMIDITY 40.59 DEGREES 0.00 138 273 6.0 INCHES 7.50 MPH 52.00 o 54.00 50.O0 a 51.00 NOTE: PRECIPITATION DATA WAS SYNTHETICALLY GENERATED USING COEFFICIENTS FOR CHEYENNE WYOMING JAN / JU L 0.41 1.87 NORMAL MEAN MONTHLY PRECIPITATION (INCHES) FEB/AUG 0.40 1.39 MAR/SEP APR/OCT MAY/NOV JUN/DEC 0.97 1.06 1.24 0.68 2.39 0.53 NOTE: TEMPERATURE DATA WAS SYNTHETICALLY GENERATED USING COEFFICIENTS FOR CHEYENNE WYOMING JAN / JU L 26.10 68.90 NORMAL MEAN MONTHLY TEMPERATURE (DEGREES FAHRENHEIT) FEB/AUG MAR/SEP APR/OCT 29.30 66.80 32.10 57.90 41.80 47.50 MAY/NOV 52.20 34.80 2.00 0.37 JUN/DEC 62.00 29.30 NOTE: SOLAR RADIATION DATA WAS SYNTHETICALLY GENERATED USING COEFFICIENTS FOR CHEYENNE WYOMING AND STATION LATITUDE = 40.59 DEGREES ******************************************************************************* MONTHLY TOTALS (IN INCHES) FOR YEAR 1 PRECIPITATION RUNOFF EVAPOTRANSPIRATION LATERAL DRAINAGE COLLECTED FROM LAYER 3 PERCOLATION/LEAKAGE THROUGH LAYER 4 JAN/ JUL FEB/AUG MAR/ SE P APR/OCT MAY/NOV JUN/DEC 0.08 2.49 0.000 0.000 0.147 2.292 0.0146 0.1078 0.1066 0.1141 0.07 0.96 0.000 0.000 0.242 0.802 0.0013 0.O879 0.0485 0.1125 1.13 1.72 0.117 0.000 0.756 2.007 0.0000 0.0777 0.0015 0.1083 0.47 0.96 0.000 0.000 0.499 0.299 0.0000 0.0597 0.0013 0.1102 MONTHLY SUMMARIES FOR DAILY HEADS (INCHES) AVERAGE DAILY HEAD ON TOP OF LAYER 4 STD. DEVIATION OF DAILY HEAD ON TOP OF LAYER 4 0.265 1.965 0.095 0.209 0.026 1.603 0.036 0.156 0.000 1.463 0.000 0.113 0.000 1.088 0.000 0.134 1.97 0.39 0.000 0.000 1.378 0.494 0.0111 0.0501 0.0468 0.1061 0.202 0.943 0.288 0.051 0.93 0.11 0.000 0.000 0.513 0.201 0.0919 0.0399 0.1094 0.1086 1.730 0.726 0.349 0.117 ******************************************************************************* ******************************************************************************* ANNUAL TOTALS FOR YEAR PRECIPITATION RUNOFF EVAPOTRANSPIRATION DRAINAGE COLLECTED FROM LAYER 3 PERC./LEAKAGE /LEAKAGE THROUGH LAYER 4 AVG. HEAD ON TOP OF LAYER 4 CHANGE IN WATER STORAGE SOIL WATER AT START OF YEAR SOIL WATER AT END OF YEAR INCHES 11.28 0.117 9.630 0.5419 0.973931 0.8343 0.018 257.494 257.511 1 CU. FEET 40946.406 423.764 34956.262 1966.929 3535 .370 64.030 93 47 01.8 75 934765.875 PERCENT 100.00 1.03 85.37 4.80 8.63 0.16 SNOW WATER AT START OF YEAR SNOW WATER AT END OF YEAR ANNUAL WATER BUDGET BALANCE 0.000 0.000 0.0000 0.000 0.000 0.049 0.00 0.00 0.00 ******************************************************************************* ******************************************************************************* AVERAGE MONTHLY VALUES IN INCHES FOR YEARS PRECIPITATION TOTALS STD. DEVIATIONS RUNOFF TOTALS STD. DEVIATIONS EVAPOTRANSPIRATION TOTALS STD. DEVIATIONS 1 THROUGH 1 JAN/JUL FEB/AUG MAR/SEP APR/OCT MAY/NOV JUN/DEC 0.08 2.49 0.00 0.00 0.000 0.000 0.000 0.000 0.147 2.292 0.000 0.000 0.07 0.96 0.00 0.00 0.000 0.000 0.000 0.000 0.242 0.802 0.000 0.000 LATERAL DRAINAGE COLLECTED FROM LAYER 3 TOTALS STD. DEVIATIONS 0.0146 0.1078 0.0000 0.0000 0.0013 0.0879 0.0000 0.0000 PERCOLATION/LEAKAGE THROUGH LAYER. 4 TOTALS STD. DEVIATIONS 0.1066 0.1141 0.0000 0.0000 0.0485 0.1125 0.0000 0.0000 1.13 1.72 0.00 0.00 0.117 0.000 0.000 0.000 0.756 2.007 0.000 0.000 0.0000 0.0777 0.0000 0.0000 0.0015 0.1083 0.0000 0.0000 0.47 0.96 0.00 0.00 0.000 0.000 0.000 0.000 0.499 0.299 0.000 0.000 0.0000 0.0597 0.0000 0.0000 0.0013 0.1102 0.0000 0.0000 1.97 0.39 0.00 0.00 0.000 0.000 0.000 0.000 1.378 0.494 0.000 0.000 0.0111 0.0501 0.0000 0.0000 0.0468 0.1061 0.0000 0.0000 0.93 0.11 0.00 0.00 0.000 0.000 0.000 0.000 0.513 0.201 0.000 0.000 0.0919 0.0399 0.0000 0.0000 0.1094 0.1086 0.0000 0.0000 AVERAGES OF MONTHLY AVERAGED DAILY HEADS (INCHES) DAILY AVERAGE HEAD ON TOP OF LAYER 4 AVERAGES STD. DEVIATIONS 0.2653 1.9647 0.0000 0.0000 0.0258 1.6028 0.0000 0.0O00 0.0000 1.4633 0.0000 0.0000 0.0000 1.0881 0.0000 0.0000 0.2020 0.9431 0.0000 0.0000 1.7300 0.7263 0.0000 0.0000 * **********-*********************-***********-*********************-***********-**** * ****************************************************************************** AVERAGE ANNUAL TOTALS & (STD. DEVIATIONS) FOR YEARS PRECIPITATION RUNOFF EVAPOTRANSPIRATION LATERAL DRAINAGE COLLECTED FROM LAYER 3 PERCOLATION/LEAKAGE THROUGH LAYER 4 AVERAGE HEAD ON T O P OF LAYER 4 CHANGE IN WATER STORAGE INCHES 11.28 0.117 9.630 0.54185 0.000) 0.0000) 0.0000) 0.00000) 0.97393 ( 0.00000) 0.834 ( 0.000) 0.018 ( 0.0000) 1 THROUGH CU. FEET 40946.4 423.76 34956.26 1966.929 3535.370 64.03 1 PERCENT 100.00 1.035 85.371 4.80367 8.63414 0.156 * ****************************************************************************** *****;k**********;k************************************************************* P h'i AID DAILY VALUHS FOR YHARS PRECIPITATION RUNOFF DRAINAGE COLLECTED FROM LAYER PERCOLATION/LEAKAGE THROUGH LAYER 4 AVERAGE HEAD ON TOP OF LAYER 4 MAX=IMUM HEAD ON TOP OF LAYHR 4 LOCATION OF MAXIMUM HHAD IN LAYER (DISTANCE FROM DRAIN) SNOW WATER MAXI MI v UM VEG XIMI.JM VHG 1 THROUGH 1 (INCH S) 0.64 0.117 0.00400 00003722 2.261 4.281 44.4 FEET (CU. FT.) 2323.200 23.7645 14 .52650 13 51O72 0.41 1476.5393 • SOIL WATHR (VOL/VOL) 0.2614 . SOIL WATHR (VOL/VOL) 0.1330 * * * Maximum heads are computed using McEnroe's equations. Reference: Maximum Saturated Depth over Landfill Liner Joy Bruce M. McEnroe, University of Kansas ASCE Journal of Environmental Engineering Vol. 119, No. 2, March 1993, pp. 262-270. *** ****************************************************************************** * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * FINAL WATHR STORAGE AT END OF YHAR 1 LAYER (INCHES) 1 1.0839 2 245_2799 3 0_4674 4 10.6800 SNOW WATER 0.000 (VOL /VOL ) 0.1806 0.2920 0.0779 0.4450 * ***************************************************************************** * ***************************************************************************** APPENDIX B I ! LTiI M ED MODEL OUTPUT APPENDIX B-1 STEADY-STATE MODEL RESULTS MULTIMED V1.01 U. S. ENVIRONMENTAL PROTECTION AGENCY EXPOSURE ASSESSMENT MULTIMEDIA MODEL MULTIMED (Version 1.50, 2005) 1 Run options North Weld Landfill, Unit 2 Alternative Liner Demonstration Chemical simulated is Leachate Constituent Option Chosen Saturated and unsaturated zone models Run was DETERMIN Infiltration Specified By User: 2.474E-02 m/yr Run was steady-state Reject runs if Y coordinate outside plume Reject runs if Z coordinate outside plume Gaussian source used in saturated zone model 1 1 1 UNSATURATED ZONE FLOW MODEL PARAMETERS (input parameter description and value) NP - Total number of nodal points NMAT - Number of different porous materials KPROP - Van Genuchten or Brooks and Corey IMSHGN - Spatial discretization option NVFLAYR - Number of layers in flow model OPTIONS CHOSEN Van Genuchten functional coefficients User defined coordinate system Layer information LAYER NO. LAYER THICKNESS MATERIAL PROPERTY 1 2 3 4 5.00 6.50 3.50 2.00 1 4 2 3 240 4 1 1 4 DATA FOR MATERIAL 1 VADOSE ZONE MATERIAL VARIABLES PARAMETERS MEAN STD DEV VAR' L I V ABLW NAM ITS IN MAX Saturated hydraulic conductivity 10.4 -999. -999. -999. Unsaturated zone porosity 0.437 -999. -999. -999. Air entry pressure head 0.000 -999. -999. -999. Depth of the unsaturated zone 17.0 0.000 0.000 0.000 PARAMETERS MEAN UNITS cm/hr -- rn rn DI STRI BUTION CONSTANT CONS TANT CONSTANT CONSTANT DATA FOR MATERIAL 1 VADOSF ZONE FUNCTION VARIARLHS VARIABLE NA L IMITS V F STD DEV MIN MAX UNITS DISTRI BUTION Residual water content 0.570E-01 -999. -999. -999. Brook and Corey xponent, H,N 999. -999. -999. -999. ALFA coefficient 0.124 -999. -999. -999. Van Genuchten exponent, ENN 2.28 -999. -999. -999. PARAME TERS WAN VARIABLE NA L IMITS v E STD DEV MIN MAX Saturatc _ hydraulic conductivity 0.310E-0 -999. -999. -999. Unsaturated zone porosity 0.550 -999. -999. -999. 1,/cm CONSTANT CONSTANT CONSTANT CONSTANT DATA FOR MATERIAL VADOSE ZONE MATERIAL VARIABLES UNITS cm/gar -- DISTRIBUTION CONSTANT CONSTANT 0.000 17.0 Air entry. pressure head -999. -999. -999. Depth of the unsaturated zone 0.000 0.000 0.000 FARAM _ H T RS MHAN VARIABLE NAME LIMITS STD DEBT MIN V AX Residual water content 0.1.00E-01 -999. -999. -999. Brook End Corey exponent, EIS 999. -999. -999. -999. ALFA coefficient 0.200E-01 -999. -999. -999_ Van Genuchten exponent, ENN 1.40 -999. -999. -999. PARAMETERS MEAN m In CONSTANT CONSTANT DATA FOR MATERIAL 2 VADOSE ZONE FUNCTION VARIABLES NITS 1/cm DISTRIBUTION CONSTANT CONSTANT CONSTANT CONSTANT DATA FOR MATERIAL 3 VADOSH ZONH V AT HR IAL VARIABLES VARIABLE NAME LIMITS STD DEV MIN .42 0.189 0.000 17.0 V AX Saturated hydraulic conductivity 999. -999. -9990 Unsaturated zone porosity - 999. -999. -999* Air entry pressure heap. - 999. -999. -999_ Depth of the unsaturated zone 0.000 0.000 0.000 UNITS DISTRI BUTTON cm/hr m m CONSTANT CONSTANT CONSTANT CONSTANT DATA FOR MATERIAL 3 aaala -- VADO E ZONE FUNCTION VARIABLES PARAMETERS MEAN VARI A _ IR L _ W NAM W LIMITS STD DEV MIN MAX Residual water content 0.650E-01 -999. -999. -999. Brook and Corey exponent,EN 999. -999. -999. -999. ALFA coefficient. 0.750E-01 -999. -999. -999. Van Genuchten exponent, ENN 1.89 -999. -999. -999. VARIABLE NAME PARAMHTIH,RS LIMITS MHAN S T D D Hi V M I N MAX 0.230 0.464 0.000 17.0 Saturated hydraulic conductivity - 999. Unsa - 999. -999. -999. turatec_ zone porosity -999. -999. Air entry pressure head -999. -999. -999. Depth of the unsaturated zone 0.000 0.000 0.000 VARIABLE NAME PARAMETERS LIMITS MEAN STD DEV MIN MAX Residual water content 0.680E-01 -999. -999. -999. Brook and Corey exponent,EN 999. -999. -999. -999. ALFA coefficient 0.800E-02 -999. -999. -999. Van Genuchten exponent, ENN 1.09 -999. -999. -999. ,NITS licm - - DISTRIBUTION CONSTANT CONSTANT CONSTANT CONS TANT DATA FOR MAT RIAL 4 VADOSE ZONE MAT IH,R IAL VARI A _ 1-3 L IH S UNITS cm/hr a- m m DISTRIBUTION CONSTANT CONSTANT CONSTANT CONSTANT DATA FOR MATERIAL 4 VADOSE ZONE FUNCTION UNITS 1/cm VARIABLES DISTRIBUTION CONS TANT CONSTANT CONSTANT CONSTANT 1 UNSATURATED ZON NLAY NTSTPS DUMMY ISOL N NTEL NGPTS NIT IBOUND ITSGEN TMAX WTFUN a - H TRANSPORT MODHL PARAMETERS Number of different layers used Number of time values concentration talc Not presently used Type of scheme used in unsaturated zone Stehfest terms or number of increments Points in Lagrangian interpolation Number of Gauss points Convolution integral segments Type of boundary condition Time values generated or input Max simulation time Weighting factor OPTIONS CHOSEN -- Convolution integral approach Nondecaying continuous source Computer generated times for computing concentrations 1 PARAME TERS MEAN \JARI AR L H NAM LIMITS STD DEV MIN 5 . 0 V AX 4 40 1 2 18 3 104 2 1 1 0.0 1.2 DATA FOR LAYER 1 VADOSE TRANSPORT \TARIAI3LI-i'S UNITS DISTRIBUTION Thickness of layer 0 -999. -999. -999. L ongitudinal dispersivity of la yer 999. 0.000 1.45 0.000 - 999. P ercent -999. Bulk - 999. - 999. -999. organic matter 999. -999. density of soil for layer - 999. -999. Biological decay coefficient -999. -999. -999. PARAME TERS VARIABLE NAM LIMITS m m -- g/cc 1/r CONSTANT DERIVED CONS TANT CONSTANT CONSTANT DATA FOR LAYER 2 VADOSE TRANSPORT VARIARLVS UNITS DISTRIBUTION MEAN STD DEV MIN MAX 6.50 999. 0.000 1.60 0.000 Thickness of layer -999. -999. -999. L ongitudinal dispersivity of layer 999. -999. -999. Percent organic matter -999. -999. -999. Bulk density of soil for layer -999. -999. -999. Biological decay coefficient -999. -999. -999. PARAMETERS MHAN 3.50 999. 0.000 2.19 0.000 VARIABLE NAME LIMITS STD DEV M I N MAX Thickness of layer 999. -999. -999. L ongitudinal dispersivity of layer 999. -999. -999. P ercent organic matter -999. -999. -999. Bulk density of soil for layer -999. -999. -999. Biological decay coefficient -999. -999. -999. VARIABLE NAME PARAMETERS LIMITS M AN STD DEV MIN MAX 2.00 999. 0.000 Thickness of layer -999. -999. -999. L ongitudinal dispersivity of layer -999. -999. -999. P ercent organic matter -999. -999. -999. m m g/cc 1/yr CONSTANT DERIVED CONSTANT CONSTANT CONS TANT DATA FOR LAYER 3 VADOSE TRANSPORT VARIARLES UNITS DISTRIBUTION m m g/cc i/yr CONSTANT DERIVED CONSTANT CONSTANT CONSTANT DATA FOR LAYER 4 VADOSE TRANSPORT VARIABLES UNITS DISTRIBUTION m m -- CONSTANT DERIVED CONSTANT Bulk density of soil for layer 1.92 -999. -999. -999. Biological decay coefficient -999. -999. -999. 0.000 1 PARAMETERS MEAN 0.000 0.000 0.000 0.000 0.000 0.000 25.0 0.000 999. 0.000 999. 999. 999. 999. 999. 999* 0.000 0.000 0.000 1 VARIABLE NAME LIMITS STD DEV MIN MAX Solid phase decay coefficient - 999. -999. Dissolved phase decay -999. -999. Overall chemical deca -999. -999. -999. coefficient -999. y coefficient -999. Acid catalyzed hydrolysis rate - 999. -999. -9999. Neutral hydrolysis rate constant -999. -999. -999. Lase catalyzed hydrolysis rate - 999. -999. -999. Reference temperature -999. -999. -999. Normalized distribution coefficient -1999. -999. -999. Distribution coefficient - 999. -999. -999. Biodegradation coefficient (sat -999. -999. -999. Air diffusion coefficient -999. -999. -999. Reference temperature for air - 999. -999. -999. Molecular weight - 999. -999. -999. Mole fraction of solute - 999. -999. Vapor pressure of -999. -999. Henry's law constant 999. -999. Overall 1st order 0.000 0.000 Not currently used 0.000 0.000 Not currentlyused 0.000 0.000 0 0 0 -999. solute - 999. g/cc 1/yr CONSTANT CONSTANT CHEMICAL SPECIFIC VARIABLES UNITS DISTRIBUTION 1/yr 1/yr 1/yr l/M-yr 1/yr l/M-yr C ml/g . zone) 1/yr cm2/s diffusion C g/M - 999_ Decay sat. zone 1.00 0.000 0.000 mm Hg atm-m"3/M 1/yr CONSTANT CONSTANT CONSTANT CONSTANT CONSTANT CONSTANT CONSTANT CONS TANT DERIVED CONSTANT CONSTANT CONSTANT CONSTANT CONSTANT CONSTANT CONSTANT DERIVED CONSTANT CONSTANT SOURCE SPECIFIC VARIABLES PARAMETERS MEAN 0.247E 188. 30.0 999. 0.000 0.000 1.0 50.0 50.0 1.00 1 VARI A _ IR L _ W NAM W LIMITS STD DEV MIN MAX Infiltration rate 01 -999. -999. -999. Area of waste disposal unit -999. -999. -999. Duration of pulse -999. -999. -999. Spread of contaminant source - 999. -999. -999. Recharge rate -999. -999. -999. Source decay constant 0.000 0.000 0.000 Initial concentration at landfill -999. -999. -999. Length scale of facility -999. -999. -999. Width scale of facility - 999. -999. -999. Near field dilution 0.000 0.000 1.00 VARIABLE NAME PARAMETERS. LIMITS MHAN STD DKV MIN 999_ 0.320 2.25 20.0 MAX Particle diameter - 999. -999_ Aquifer porosity -999. -999. Bulk density -999. -999. Aquifer thickness -999. -999. Source thickness 999E -999. -999. 0.380E+04 0.300E-02 999. 999. 999. 999. -999. Gradient -999. - 999. -999. -999. - 999_ (mixing zone depth) - 999. Conductivity (hydraulic) - 999. -999. (hydraulic) - 999. -999_ Groundwater seepage velocity -999. -999. -999. Retardation coefficient -999. -999. -999. Longitudinal dispersivity - 999. -999. -999. Transverse dis_oersivity - 999. -999. -999. UNITS m/yr m"2 m m/ yr 1/yr mg/1 m m DISTRIBUTION CONSTANT CONSTANT CONSTANT DERIVED CONSTANT CONSTANT CONSTANT DERIVED DERIVED DERIVED AQUIFER SPECIFIC VARIABLES UNITS cm g/cc m m/ yr m/ yr DISTRIBUTION CONSTANT CONSTANT CONSTANT CONSTANT DERIVED CONSTANT CONSTANT DERIVED DERIVED FUNCTION OF FUNCTION OF Vertical dispersivity 999. -999. -999. -999. Temperature of aquifer 13.3 -999. -999. -999 pH 7.66 -999. -999. -999. Organic carbon content (fraction) 0.500 -999. -999. -999. Well distance from site 34.0 999. -999. -999. Angle off center 0.000 0.000 0.000 0.000 Well vertical distance 0.000 0.000 0.000 0.000 . m C m degree m CONCENTRATION AFTER SATURATED ZONE MODEL 0.4530E-02 FUNCTION OF X CONSTANT CONSTANT CONSTANT CONSTANT CONSTANT CONS TANT ►PPENDI B-2 TRANIENT MODEL RESULTS MULTIMED V1.01 U. S. ENVIRONMENTAL PROTECTION AGENCY EXPOSURE ASSESSMENT MULTIMEDIA MODEL MULTIMED (Version 1.50, 2005) 1 Run options North Weld Landfill, Unit 2 Alternative Liner Demonstration Chemical simulated is Leachate Constituent Option Chosen Saturated and unsaturated zone models Run was DETERMIN Infiltration Specified By User: 2.474E-02 m/yr Run was transient Well Times: Entered Explicitly Reject runs if Y coordinate outside plume Reject runs if Z coordinate outside plume Gaussian source used in saturated zone model 1 1 UNSATURATED ZONE FLOW MODEL PARAMETERS (input parameter description and value) NP - Total number of nodal points NMAT Number of different porous materials KPROP - Van Genuchten or Brooks and Corey IMSHGN - Spatial discretization option NVFLAYR - Number of layers in flow model OPTIONS CHOSEN Van Genuchten functional coefficients User defined coordinate system 1 Layer information LAYER N O . 1 2 3 4 LAYER THICKNESS MATERIAL PROPERTY 5.00 6.50 3.50 2.00 1 4 2 3 240 4 1 1 4 DATA FOR MATERIAL 1 VADOSE ZONE MATERIAL VARIABLES VARIABLE NAME PARAMETERS LIMITS MEAN 10.4 0.437 0.000 17.0 STD DEV MIN MAX Saturated hydraulic conductivity -999. -999. -999. Unsaturated zone porosity -999. -999. -999. Air entry pressure head -999. -999. -999. Depth of the unsaturated zone 0.000 0.000 0.000 VARIABLE NAME PARAMETERS LIMITS MEAN STD DEV MIN MAX Residual water content 0.570E-01 -999. -999. -999. Brook and Corey exponent,EN 999. -999. -999. -999. ALFA coefficient 0.124 -999. -999. -999. Van Genuchten exponent, ENN 2.28 -999. -999. -999. VARIABLE NAME PARAMETERS LIMITS MEAN STD DEV MIN MAX Saturated hydraulic conductivity 0.310E-02 -999. -999. -999. UNITS cm/hr m m DISTRIBUTION CONSTANT CONSTANT CONSTANT CONSTANT DATA FOR MATERIAL 1 VADOSE ZONE FUNCTION VARIABLES UNITS 1/cm DISTRIBUTION CONSTANT CONSTANT CONSTANT CONSTANT DATA FOR MATERIAL 2 VADOSE ZONE MATERIAL VARIABLES UNITS cm/hr DISTRIBUTION CONSTANT 0.550 0.000 17.0 Unsaturated zone porosity -999. -999. -999. Air entry pressure head -999. -999. -999. Depth of the unsaturated zone 0.000 0.000 0.000 PARAMETERS MHAN VARIABLE NAME LIMITS STD DEV .MIN MAX 0.100P-01 999. 0.2 OH -01 1.40 Residual watercontent -999. -999. -999. Brook and Corey exponent, EN 999. -999. -999. ALFA coefficient -999. -999. -999. Van. Cenuchten exponent, ENN 999. -999. -999. VARIABLE NAME PARAMETERS LIMITS MhfiAID] STD DEV MIN MAX Saturated hydraulic conductivity 4.42 -999. -999. -999. Unsaturated zone -Porosity 0.-189 -9996 -9990 -999. Air entry Pressure heap. 0.000 -999. -999. -999. Depth of the unsaturated zone 17.0 0.000 0.000 0.000 m m CONSTANT CONSTANT CONSTANT DATA FOR MATERIAL 2 VADOSE ZONE FUNCTION VARIABLES UNITS 1/cm DATA FO DISTRIBUTION CONSTANT CONSTANT CONSTANT CONSTANT YATVRIAL 3 VADOSE ZONIH, MATERIAL VARIAI-3LIHS UNITS C m m /hr DISTRIBUTION CONSTANT CONS TANT CONSTANT CONSTANT DATA FOR MATERIAL 3 VADOSE Z NE FUNCT IO VARIABLES PARAMETERS VARIARLW NAM L IMITS MEAN STD DEV MIN V AX Residual water content 0.650E-01 -999. -999. -999. Brook and Corey exponent, EN 999. -999. -999. -999. ALFA coefficient 0.750E-01 -999. -999. -999. Van Genuchten exponent, ENK 1.89 -999. -999. -999. PARAMHT RS MKAN 0.230 0.464 0.000 17.0 STD DEV V VARIABLE NAME L IMITS IN MAX UNITS DISTRIBUTION 1/cm CONSTANT CONSTANT CONS TANT CONSTANT DATA FOR MATERIAL 4 VADOSE ZONE UNITS MATERIAL VARIARLHS DISTRIBUTION Saturated hydraulic conductivity -999. -999. -999. Unsaturated zone porosity -999. Air entry . -999. -999. pressure head -999. -999. Depth of the unsaturated zone .000 0.000 0.000 PARAMETERS M AN VARIABLE NAME L IMITS STD DEV MIN MAX Residual water content 0.680E-01 -999. -999. -999. Brook and Corey exponent,HN 999. -999. -999. -999. ALFA coefficient 0.800E-02 -999. -999. -999. cm/ hr m m CONSTANT CONSTANT CONSTANT CONSTANT DATA FOR MATERIAL 4 VADOSE ZONE FUNCTION UNITS 1/cm VARIABLES DISTRIBUTION CONSTANT CONSTANT CONSTANT 1.09 1 1 Van Genuchten exponent, ENN 999. -999. -999. U NSATURATVD ZONE TRANS NLAY N TSTPS DUMMY ISOL N NTEL NGPTS NIT 'BOUND ITSGEN TMAX WTFUN a FORT MODFL PARAMHTHRS Number of different layers used Number of time values concentration calc Not presently used Type of scheme used in unsaturated zone Stehfest terms or number of increments Points in Lagrangian interpolation Number of Gauss points Convolution integral segments Type of boundary condition Time values generated or input YEX simulation time Weighting factor OPTIONS CHOSEN -- Convolution integral approach Nondecaying pulse source Computer generated times for computing concentrations CONSTANT 4 1 2 18 3 104 2 2 1 0.0 1.2 DATA FOR LAYER 1 \ADOSE TRANSPORT VARIABLES PARAMETERS MEAN STD DEV VARI LI v ABLW NAM ITS IN MAX UNITS DISTRIBUTION 5.00 999. 0.000 1.45 Thickness of layer - 999. -999. -999. L ongitudinal dispersivity of layer - 999. -999. -999. P ercent organic matter -999. -999. -999. Bulk density of soil for layer -999. -999. -999. Biological decay coefficient 0.000 -999. -999. -999. m m g/cc 1/yr yr CONSTANT DERIVED CONSTANT CONSTANT CONSTANT DATA FOR LAYER 2 \ADOSE TRANSPORT VARIABLES VARI A _ IR L _ W NAM W PARAMETERS LIMITS MEAN STD DEV MIN MAX Thickness of layer 6.50 -999. -999. -999. L ongitudinal dispersivity of layer 999. -999. -999. -999. Percent organic matter 0.000 -999. -999. -999. Bulk density of soil for layer 1.60 -999. -999. -999. Biological decay coefficient 0.000 -999. -999. -999. VARIABLE NAME PARAMHTHRS LIMITS MHAN 3.50 999. 0.000 2.19 0.000 STD DEV V IN MAX Thic-mess of layer -999. -999. -999. L ongitudinal dispersivity of layer -999. -999. -999. P ercent organic matter -999. -999. -999. Bulk density of soil for layer -999. -999. -999. Biological decay coefficient -999. -999. -999. PARAMETERS ICI AID VARIABLE NA LIMITS v E STD DEV MIN MAX Thickness of layer 2.00 -999. -999. -999. L ongitudinal dispersivity of layer 999. -999. -999. -999. UNITS m m g/cc 1/yr DISTRI BUTI0N CN CONSTANT DERIVED CONSTANT CONS TANT CONSTANT DATA FOR LAYER 3 VADOSH TRANSPORT VARIARLH S UNITS DISTRIBUTION m m g/cc 1/yr CONSTANT DERIVED CONSTANT CONSTANT CONSTANT DATA FOR LAYER 4 VADOSE TRANSPORT VARIABLES UNITS DISTRIBUTION m rn CONSTANT DERIVED Percent organic matter 0.000 -999. -999. -999. Bulk density of soil for layer 1.92 -999. -999. -999. Biological decay coefficient 0.000 -999. -999. -999. 1 VARIABLE NAM PARAMETERS LIMITS MEAN 0.000 0.000 0.000 0.000 0.000 0.000 25.0 0.000 999. 0.000 999. 999. 999. 999. 999* 999. 0.000 0.000 0.000 1 STD DEV MIN MAX Solid phase decay coefficient -999. -999. -999. Dissolved phase decay coefficient -999. - 999. -999. Overall chemical decay coefficient - 999. -999. -999. Acid catalyzed hydrolysis rate - 999. -999. -999. Neutral hydrolysis rate constant - 999. -999. -999. Base catalyzed hydrolysis rate - 999. -999. -999. Reference temperature - 999. -999. -999. Normalized distribution coefficient - 999. -999. -999. Distribution coefficient -999. -999. -999. Biodegradation coefficient (sat. -999. -999. -999. Air diffusion coefficient g/ cc 1/yr CONSTANT CONSTANT CONSTANT CHEMICAL SPECIFIC VARIABLES UNITS 1/yr 1/yr 1/yr 1 /M- yr 1/yr l/M-yr C ml /g zone) 1/yr cm /s -999. -999_ -999. Reference temperature for air diffusion C - 999. -999. -999. Molecular weight g/M - 999. -999. -999. Mole fraction of solute -999. -999. -999_ Vapor pressure of solute - 999. -999. -999. Henry's law constant -999. -999. -999. Overall 1st order decay sat. zone 0.000 0.000 1.00 Not currently used 0.000 0.000 Not currently used 0.000 0.000 0.000 0.000 mm Hg atm-mA3 /M 1/yr DISTRIBUTION CONSTANT CONSTANT CONSTANT CONSTANT CONSTANT CONSTANT CONSTANT CONSTANT DERIVED CONSTANT CONSTANT CONSTANT CONSTANT CONSTANT CONSTANT CONSTANT DERIVED CONSTANT CONSTANT SOURCE SPECIFIC VARIABLES PARAMETERS MEAN \JARI AR L H NAM LIMITS STD DEV MIN V AX Infiltration rate 0.247E-01 -999. -999. -999. Area of waste disposal unit 0.118 -999. -999. -999. Duration of pulse 35.0 -999. -999. -999. Spread of contaminant source 999. -999. -999. -999. Recharge rate 0.000 -999. -999. -999. Source decay constant 0.000 0.000 0.000 0.000 Initial concentration at landfill 1.00 -999. -999. -999. Length scale of facility 50.0 -999. -999. -999. Width scale of facility 50.0 -999. -999. -999. Near field dilution 1.00 0.000 0.000 1.00 1 PARAMETERS MEAN 999. 0.320 2.25 20.0 999. 0.380H+0 0.300H-02 999. 999. 999. STD DEV VARIABLE NA LIMITS MIN V E MAX Particle ciameter -999. -999. -999. Aquifer porosity - 999. -999. Bulk density -999. -999. -999_ Aquifer thickness -999. -999* -999. Source thickness (mixing zone c - 999. -999. -999. Conductivity (hydraulic) - 999. -999. -999. Gradient (hydraulic) - 999. -999. -999. Groundwater seepage velocity -999. -999. -999. Retardation coefficient - 999. -999. -999. Longitudinal dispersivity - 999. -999. -999. 999. epth) UNITS m/yr m"2 yr m rn/yr 1/yr mg/1 rn m DISTRIBUTION CONSTANT CONSTANT CONS TANT DERIVED CONSTANT CONSTANT CONSTANT DERIVED DERIVED DE R I VPI D AQUIFER SP CI, 'IC VARIABLWS UNITS cm g/cc m. m m/yr m/ yr -- m DISTRIBUTION CONSTANT CONSTANT CONSTANT CONS TANT DERIVED CONSTANT CONSTANT DERIVED DERIVED FUNCTION OF 999. 999. 13.3 7.66 0.500 708. -999. 0.000 0.000 1 Transverse dispersivity - 999. -999. -999. Vertical dispersivity - 999. -999. -999. Temperature of aquifer - 999. -999. -999. pH -999. -999. -999. Organic carbon content (fraction) -999. -999. -999. Well distance from site -999. -999. Angle off center - 999. -999. -999. Well vertical distance - 999. -999. -999. m m C m degree T I ME FUNCTION OF X FUNCTION OF X CONSTANT CONSTANT CONSTANT CONSTANT CONS TANT CONSTANT CONCENTRAT ION 0.100E+01 0.500E+01 0.100E+02 0_150E+02 0.200E+02 0.250E+02 0.300E+02 0.350E+02 0.400E+02 0.450E+02 0.500E+02 0.550E+02 0.600E+02 0. 650E+02 0. 00 0 0 0E+0 0 0.00000E+00 3.77870E-25 0.12612E-18 0.78095E-17 0.54167E-16 0.16369E-15 0.33079E-15 0.53470E-15 0.75499E-15 0.9751.7E-15 0.11056E-13 0.15046E-10 0.25359E-09 APPENDIX J CDPHE APPROVAL WITH CONDITIONS TO USE GLASS GULLET FOR LEACHATE COLLECTION SYSTEM STAJ'E OF C LORA Fail litter, Jr., Governor Martha E. Rudolph, Executive Director Dedicated to protecting and improving the health and environment of the people of Colorado 1300 Cherry Creek Dr. S. Denver, Colorado 8.0246-1530 Phone (303) 692-2000 TEC Line (303) 691-7700 Loc,ted in Glendale. Colorado http://www.cdphe.state.co.us ]:'arch 3, 9010 Laboratory Services Division 8100 Lowry Blvd. Denver, Colorado 80230-6928 (303) 692-3090 Mr. Torn Schweitzer Waste Management. of Colorado, Inc. 2400 West Union Avenue Englewood, CO 80110 ,.-S Colorado Department of Public Health and Environment Re: Final Agency Action: Approval With Conditions to. Use Glass Cullet for Leachate Collection System Dear Mr. Schweitzer: The Colorado Department of Public Health & Environment, Hazardous Materials and Waste Management Division (the "Division") has considered your proposal requesting the use of glass e Lt l l et in lieu of natural sand and gravel materials for leachate collection drainage layers and drain lines in Waste Management of Colorado, Inc. (WM) clay -lined municipal solid waste landfills. The proposal was received in our office on September 9, 2009. On November 19, 2009 the Division sent comments to WM concerning the proposal. A meeting between the Division and p�. WM and their consultant (Golder- Associates) was held December 18, 2009 to address the comments ant discuss other issues„. forrimal written response from WM was received on January 5, 2010. In the interim, several telephone calls and cma is were also exchanged between WM and the Division. Based upon the information provided in the proposal along with the follow-up discussions, the Division hereby approves, as final agency, WM's use of glass cutlet for leachate collection drainage layers and drain lines with the following conditions:. 1. As described in the letters to the Division, WM should perform pre -construction hydraulic conductivity testing to verify that the glass planned for use will achieve the desired hydraulic conductivity. The frequencies for testing should be the same as those approved for each facility's lity's specific Engineering Design and Operations Plan(EDOP). p 2. The glass cullet layer thickness should be increased so that upon final loading the minimum design thickness is still maintained, This concept is described in the proposal submitted to the .Division* Each WM facility that proposes to use the glass cullet shall amend their respective EDOPs to reflect the change. The amended EDOP shall be submitted to the Division for review and approval.. In closing, The Division is authorized to bill for its review of technical submittals at $125 per hour, pursuant to Section 1.7 of the solid waste regulations 6 CCR 1007-2. An invoice for the Division's review of the above referenced document will be sent under separate cover. Should you have any questions regarding this letteror would Jike to discuss any of the items contained in this letter, I can be reached at 303-692-3384 or email at Nr=r•��.brus in@state.e , Sincerely, Gt, ,0"/„>•'' Larry 13ruski u Solid Waste and Material al Ian.age ment Unit Hazardous Materials and waste Management Division cc: Mark McClain, Golder file: s laraida.dl ,7 APPENDIX K ALTERNATIVE DAILY COVER MATERIALS CDPHE AND WCDPHE APPROVAL LETTERS V 1 4,- y WIDc COLORADO October 5, 1993 Bill Hedberg Waste Services Corporation 6037 77th Avenue Greeley, Colorado 80634 Alan Scheere Waste Services Corporation 6037 77th Avenue Greeley, Colorado 80634 Dear Mr. Hedberg and Mr. Scheere: fVEO OCT 1 2 1993 key( tire., DEPARTMENT OF HEALTH 1517- 16 AVENUE COURT GREELEY, COLORADO 80631 ADMINISTRATION (303) 353-0586 HEALTH PROTECTION (303) 353-0635 COMMUNITY HEALTH (303) 353-0639 The Environmental Protection Division of the Weld County Health Department has reviewed your letter dated September 3, 1993, regarding daily cover and alternative daily cover at both the Central Weld Sanitary Landfill and the North Weld Sanitary Landfill, Weld County. The Division approves of the use of soil as a daily cover material, including contaminated soils and street sweepings, provided it is applied to a depth of at least six (6) inches. The Division also approves of the use of a synthetic alternative daily cover, provided: 1) The material controls disease vectors, fires, odors, blowing litter, scavenging and other nuisance conditions without presenting a threat to human health and the environment. An adequate soil stockpile is readily available in the event of extreme conditions. The facility also requested approval for the use of shredded tire chips (two inch nominal thickness) and Sanifoaxn or an equivalent foam ADC material (two inch nominal thickness) . The Divisionwill consider approval for each of these materials after adequate demonstration from the facility that these materials can adequately control disease vectors, fires, odors, blowing litter, scavenging and other nuisance conditions without presenting a threat to human health and the environment. Bill Hedberg Waste Services Corporation Alan Scheere Waste Services Corporation October 6, �P n 1993 Page 2 If you have and questions, , please contact Trevor Jiricek at 353a0635. Sincerely, /Iva , r C Trevor Jiricek, Supervisor Environmental Protection Services TJ/ cs-203 I cc: Roger Doak, Colorado Department F� rtment of Health t STATE OF COLORADO Bill Owens, Governor Douglas H. Benevento, Executive Director Dedicated to protecting and improving the health and environment of the people of Colorado 4300 Cherry Creek Dr. S. Denver, Colorado 80246-1530 Phone (303) 692-2000 TDD Line (303) 691-7700 Located in Glendale, Colorado http://www.cdphastate,co.us February 11, 2003 Mr. Alan Scheere Waste Management 7780 E. 96° Avenue Henderson, CO 80640 Laboratory and Radiation Services Division 8100 Lowry Blvd. Denver, Colorado 80230-6928 (303) 692-3090 RE: Alternative Daily Covers Request for North Weld Landfill (NWLF) Dear Mr. Scheere, Colorado Department of Public Health and Environment This is a Hazardous Materials and Waste Management Division (Division) response to your (and Bill Hedberg's) January 21, 2003 letter that requests approval for the use of the fallowing alternative daily cover materials at NWLF: • Ash from municipal waste combustors and utility companies; • Compost -based materials; • Foundry sand; • Yard waste such as lawn clippings, leaves and tree branches; • Sludge -based materials (Le., sludge treated with lime and mixed with ash or soil); • Construction and demolition debris; • Shredded tires; • Discarded carpets; • Grit from municipal wastewater treatment plants; • Shredder fluff from salvage yards; • Glass Cutlet; and • Geotextile fabric. The Division approves of your request with the following conditions: 1. At least one day a week a minimum six-inch thick earthen cover will be placed over the waste. This earthen cover shall remain in place. This statement is designed to ensure that an earthen layer remains in place as opposed to common practice of removing the previous day's earthen cover at the beginning of a new day of operation. The Division feels that this Mr. Alan Scheere February 11, 2003 Page 2 requirement is reasonable because of the amount of air space gained from using materials that would normally be disposed of in the landfill, as daily cover, 2. Should there be any complaints of trash blowing out of the landfill, this approval may be revoked. 3. Should there be any complaints related to vermin such as flies and/or a noticeable increase in bird activity, this approval may be revoked. Hazardous wastes shall not be used as daily cover. 5. If the total alpha activity of the sludge exceeds 40 picocuries per gram of dry sludge, the sludge generator shall contact the Colorado Department of Public Health and Environment's Laboratory and Radiation Services Division for further guidance regarding its use as an alternative daily cover material. 6. Hazardous Substances Response Fund is to be paid on these materials. 7. Approval from Weld County must be obtained. Please contact me at 303-692-3389 if you have any questions. Sincerely, g),,,e4L-174 JiLLeivvc, Douglas M. Ikenberry Solid Waste Unit Compliance Program Cc: Bill Hedberg, North Weld Landfill Cindi Etcheverry, Weld County Department of Public Health and Environment FILE: SWWLDNW2.5 COLORADO March 17, 2003 DEPARTMENT OF PUBLIC HEALTH & ENVIRONMENT 1555 N. 17th Avenue Greeley, CO 80631 WEBSITE: www.co.weld.co.us ADMINISTRATION: (970) 304-6410 FAX: (970) 304-6412 PUBLIC HEALTH EDUCATION & NURSING: (970) 304-6420 FAX: (970) 304-6416 ENVIRONMENTAL HEALTH SERVICES: (970) 304-6415 FAX: (970) 304-6411 Alan Scheere Waste Management 7780 E. 96th Avenue Henderson, CO 80233 Bill Hedberg North Weld Sanitary Landfill 40,000 Weld County Road 25 Ault, CO 80610-9748 Subject: North Weld Sanitary Landfill - Request for Use of Alternative Daily Cover The Weld County Department of Public Health and Environment (WCDPHE) has reviewed your letter dated January 21, 2003 requesting the use of ash from municipal waste combustors and utility companies, compost -based materials, foundry sand from the manufacturing process of discarding used dies, yard waste such as lawn clippings, leaves and tree branches, sludge -based materials (i.e. sludge treated with lime and mixed with ash or soil), construction and demolition debris, shredded automobile tires, discarded carpets, grit from municipal wastewater treatment plants, shredder fluff from salvage yards, class cullet, and geotextile fabric as alternative daily cover (ADC) materials. The proposed ADC materials would be used at the above referenced facility located at 40000 Weld County Road 25. As you state in your letter, the Colorado Department of Public Health and Environment (CDPHE) requested a comprehensive list of potential daily cover materials proposed for use as daily cover to eliminate the need for future individual approvals. Included in your letter is an approval letter from the CDPHE, datedNovember 15, 2002 for the Colorado Springs and Midway Landfills, which approves the above mentioned ADC materials provided that at least one day a week a six-inch earthen cover be placed over the waste, if complaints of trash blowing out of the landfill occur the approval may be revoked, and providing the governing body gives an approval. The materials that you have requested to use as ADC at the North Weld Sanitary Landfill are listed below. 1. Ash from municipal waste combustors and utility companies, 2. Compost- based material, 3. Foundry sand from the manufacturing process of discarding used dies, 4. Yard waste such as lawn clippings, leaves, and tree branches, 5. Sludge based materials (i.e., sludge treated with lime and mixed with ash or soil), Alan Sheere & Bill Hedberg March 17, 2003 Page 2 6. Construction and demolition debris, 7. Shredded tires, 8. Discarded carpets, 9. Grit from municipal wastwater treatment plants, 10. Shredder fluff from salvage yards, 11. Glass Cutlet, and 12. Geotextile fabric. Providing that you abide by the conditions in the CDPHE letter and Doug Ikenberry's approval letter dated February 11, 2003, WCDPHE approves the use of the above listed materials for use as ADC. However, in the event that a nuisance condition or an operational problem associated with the use of above materials is determined, WCDPHE reserves the right to revoke our approval. Should you have any questions regarding this letter, please contact me at (970) 304-6415, extension 2220. Sincerely, (t-sectilifeeeffe d Cs itcles °tea tie Cindi Etcheverry E. H. Supervisor Environmental Health Services cc: Trevor Jiricek, Director, Environmental Health Services (via email) Doug Ikenberry, Colorado Department of Pubic Health and Environment Glen Mallory, Colorado Department of Public Health and Environment (via email) Lee Morrison, Weld County Attorneys Office (via email) Kim Ogle, Department of Planning Services (via email) O:\ETCH\WASTE\Nwsi1030314revised ADC approval,doc COLORADO Department of Public Health 84 Environment Dedicated to protecting and improving the health and environment of the people of Colorado May 28, 2015 Mr. Bruce CLabaugh, M.S., R.S. Waste Management 5500 South Quebec Street, Suite 250 Greenwood Village, Co 80111 Re: Revised Approval With Conditions: Request Dated November 12, 2014 to Use Street Sweepings as Alternative Daily Cover at Waste Management of Colorado, Inc., Landfills: North Weld Landfill, Buffalo Ridge Landfill, Denver Arapahoe Disposal Site, Colorado Springs Landfill, Midway Landfill, Montrose Landfill, CSI Landfill Files: SW/WLD/NWC 2.2 SW/WLD/BRL 2.2 SW/ARA/GLAD 2.2 SW/ELP/CSL 2.2 S1/ELP/MLA` 2.2 S /MOT/MON 2.2 SW/ADM/CSI 2.2 Dear Mr. Clabaugh: The Colorado Department of Public Health and Environment, Hazardous Materials and Waste Management Division (the "Division") reviewed your request to allow street sweepings to be used as alternative daily cover ("ADC") at the seven above -reference landfills. Based on this review, the Division provided an approval letter with conditions dated December 24, 2014. Waste Management subsequently requested clarification of several of the conditions. The Division herby approves the request to use street sweepings as ADC with the following revised conditions: 1. Street sweepings generated from a spill /release response should be properly characterized and disposed and should not be used as ADC. 2. Pursuant to Section 2.1.3 of the Regulations Pertaining to Solid Waste Sites and Facilities, 6 CC P. 1007- 2, Part 1 ("Solid Waste Regulations") street sweepings must be managed in a manner such that dust does not constitute a hazard to human health. 3. Sto rrnwater that comes in contact with refuse, street sweepings, and other ADC must be managed separately in accordance with each facility's storniwater management plan and leachate management plan. 4. Street sweepings used as AX must be applied in the smallest practical area pursuant to Section 2.1.10 of the Solid Waste Regulations. 5. A six-inch layer of soil cover must be placed over street sweepings and other ADC at least one day per week. Soil cover placed over ADC shall not be removed. 4300 Cherry Creek Drive S., Denver, CO 80246.1530 P 303-692-2000 wvvw.cotorado. gov/cdphe John W. Hickentooper, Governor I Larry Wolk, MD, MSPH, Executive Director and Chief Medical Officer Mr. Bruce CLabaugh, M.S., R.S. May 28, 2015 Page 2 In closing, the Division is authorized to bill for its review of technical submittals at $125 per hour, pursuant to Section 1.7 of the Solid Waste Regulations. An invoice for the Division's review of the above -referenced document will be sent under separate cover. Should you have any questions regarding this letter, I may be reached by phone at 303-692-2295 or email at curtis.stovaLt@stateoco.us. Sincerely, Curt Stovall, P.E. Solid Waste Permitting Unit Solid Waste a Materials Management Program Hazardous Materials Et Waste Management Division cc: Heather Barbare, Weld County Department of Public Health and Environment James Talournis, Weld County Department of Public Health and Environment Diane DeLillle, City and County of Denver Deanne Kelly, TN -County Health Department Mark Gebhart, El Paso County Development Services Ken WinckLer, Montrose County Jennifer Rutter, Adams County Planning and Development Department ec: Jerry Henderson, HMWMD Bob Peterson, HMWMD Jace Driver, HMWMD Andy Todd, P.E., HMWMD 4300 Cherry Creek Drive S., Denver, CO 80246-1530 P 303-692-2000 www.colorado.govircdphe John \N. Hic enlooiler, Governor Larry oLk, MD, MSPH, Executive Director and Chief Medical Officer Hello