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Home My WebLink About20032982.tiff re _. et & gillig BOARD OF COUNTY COMMISSIONERS PHONE (970) 336-7204, Ext. 4200 ' FAX: (970) 352-0242 P. O. BOX 758 WiiC. GREELEY, COLORADO 80632 COLORADO October 2, 2003 FARFRUMWURKIN, LLLP C/O LANDPROFESSIONALS, LLC ATTN: ROBB CASSEDAY 4311 HIGHWAY 66 SUITE 4 LONGMONT CO 80504 Dear Mr. Casseday: Your application for a Change of Zone from A (Agricultural) to PUD ( Planned Unit Development) for nine (9) lots with E (Estate) Uses, along with 3.68 acres of open space - Filly Ridge, has been recommended unfavorably to the Board of County Commissioners by the Planning Commission. The legal description of the property involved is shown as Lot A of Recorded Exemption #3474; being part of the SW 1/4 of Section 32, Township 2 North, Range 68 West of the 6th P.M., Weld County, Colorado. If you wish to be heard by the Board of County Commissioners, it will be necessary for you to indicate your request by signing the bottom of this letter and returning it to this office. Regular hearing procedures will then be followed. In order to proceed as quickly as possible, we must receive your reply by November 2, 2003. If we are not in receipt of your request by that date, the matter will be considered closed. Sincerely, BOARD OF COUNTY COMMISSIONERS WF UNTY, G0 A:7O David E. Long, Chair DEL/db / 7 / I/we, , {r-« , do hereby request the Board of County Comrnfssioners to consider the above n ,tioned application. EXHIBIT I ii 2003-2982 1 E Pd#x/0,.7 DANIEL F.BERNARD BERNARD LYONS 303-776-9900 RICHARD N.LYONS,II GADDIS & KAHN FAX 303-413-1003 JEFFREY J.KAHN E-MAIL info@blglaw.com law.com JOHN W.GADDIS G B BRADLEY A.HALL A PROFESSIONAL CORPORATION ATTORNEYS AND COUNSELORS Mailing address: STEVEN P.JEFFERS POST OFFICE BOX 978 WENDY SLEE RUDNIK LONGMONT,CO 80502-0978 ANTON V.DWORAK ADELE L.REESTER Street address: MADOLINE E.S.WALLACE SECOND FLOOR EVE I.CANFIELD 515 KIMBARK STREET mwallace@blglaw.com October 22, 2003 Jacqueline Hatch, Planner Weld County Planning Department 1555 N. 17th Avenue Greeley, CO 80631 Re: Weld Count;'Referral No. P7 1027(Application of Farfrumwurkin, LLLP) Dear Ms. Hatch: Our firm represents the Consolidated Lower Boulder Reservoir and Ditch Company ("Ditch Company"), which owns the Lower Boulder Ditch ("Ditch"). The Ditch Company recently received a referral for the change of zone application of Farfrumwurkin, LLLP ("LLLP") for Filly Ridge PUD. The application requests Weld County's permission to subdivide the LLLP Property, on which the Ditch Company's Ditch and easement for the operation, maintenance, repair and replacement of the Ditch occur. Please ensure that any approval granted by Weld County to LLLP notes that ditch alterations (relocating, sloping or piping), ditch crossings (over, under, or through the ditch), encroachments on the easement (trees, structures, fences, etc.) and discharges of storm water into the Ditch are prohibited unless LLC and the Ditch Company enter into an agreement. Also note that as part of the cleaning and maintenance of the Ditch, the Ditch Company may pile muck and debris from the Ditch on the Ditch's banks. This practice is a normal maintenance activity and is included as part of the easement. Please call me if you have questions. Best regards, BE ':'ARD, YO ADDIS & KAHN, a Pr.fession.1 C. �Y I Madrlin . . la•e� MEW:mew cc: Alfred Sater, President, Consolidated Lo • t oulder Reservoir and Ditch Company David Yardley, Secretary, Consolidated Lower Boulder Reservoir and Ditch Company Robert Casseday, AgPro Environmental Services soon G:\CLIENTS\N\NEWLB\FILLY RIDGE\L WELD COUNTY RE FILLY RIDGE REFERAL.DOC /2 10/22/03 4311 Highway 66, Suite 4 Longmont, CO 80504 Office (970) 535-9318 Metro (303)485-7838 Fax: (970) 535-9854 . _ k LANDPROfessionals, LLC November 3, 2003 Dear Ms. Mika: Enclosed is the updated drainage report for the Filly Ridge subdivision. A copy has been provided to Public Works. If you have any questions please contact us Sincerely, jj.;_kh iyz ///,‘," viz z ,/ Robb R. Casseday / Lauren Light Architect/Land Planner Planner LA NDPROfessionals, LLC (970) 535-9318 Office (970) 535-9854 Fax (303) 485-7838 Metro (303) 870-0014 Cell 4311 Highway 66, Suite 4 Longmont, CO 80504 rcasseday@agpros.com EXHIBIT I a 4311 Highway 66,Suite 4 Longmont,CO 80504 Office: (970)535-9318 Fax: (970)535-9854 LANDPROfessionals, LLC October 30,2003 Weld County Department of Public Works 1111 H Street, P.O. Box 758 Greeley, Colorado 80632 RE: Filly Ridge PUD, Storm Drainage Report To Whom It May Concern: This Storm Drainage Report for Filly Ridge PUD was prepared by me,or under my direct supervision, in accordance with Weld County Subdivision Regulations, Section 24-7-120. Sincerely, %QpDO•Rf0js W.DU•.<`� • 3 %Iola-0V 1/47 Si0NAL E\k Eric W. Dunker, P.E. Environmental Engineer Colorado Registration No. 33915 STORM DRAINAGE REPORT FOR FILLY RIDGE PLANNED UNIT DEVELOPMENT Prepared for: Farmfrumwurkin, LLLP 11811 Upham Street, #12 Broomfield, CO 80020 Prepared by: LANDPROfessionals, LLC 4311 Hwy 66, Suite 4 Longmont, CO 80504 (970) 535-9318 Eric W. Dunker, P.E. Environmental Engineer October 30, 2003 Filly Ridge PUD 10.30.2003 TABLE OF CONTENTS PROPOSED PROJECT LOCATION AND DESCRIPTION 3 NEARBY DEVELOPMENT 3 CURRENT PROPERTY CONDITION AND HISTORIC DRAINAGE PATTERN 3 AREA DRAINAGE DESCRIPTION 3 OFF-SITE DRAINAGE AFFECTING DEVELOPMENT 4 DRAINAGE DESIGN CONCEPT 4 HISTORIC AND DEVELOPED FLOWS 4 DETENTION VOLUME 5 IRRIGATION POND 5 SWALE DESIGN 5 OUTFALL DESIGN 5 MAINTENANCE ACCESS 6 CONCLUSION 6 COMPLIANCE 6 APPENDIX A 7 • DRAINAGE PLAN MAP 7 • OUTFALL DETAIL MAPS 7 • AREA DRAINAGE MAP 7 • FLOODPLAIN MAP 7 APPENDIX B 8 • RATIONAL METHOD CALCULATIONS 8 • DETENTION POND SIZING CALCULATIONS 8 • SWALE DESIGN CALCULATIONS 8 • ORIFICE PLATE DESIGN CALCULATIONS 8 APPENDIX C 9 • TABLES AND FIGURES UTILIZED FOR CALCULATIONS 9 Storm Drainage Report LANDPROfessionals, LLC 2 Filly Ridge PUD 10.30.2003 Proposed Project Location and Description The Filly Ridge project is a proposed residential development as a Planned Unit Development (PUD). The property is located in the southwest one-quarter of the southwest one-quarter of section thirty-two, township two north, range sixty-eight west, of the sixth principle meridian, Weld County, Colorado. The property is at the northwest corner of the intersection of Weld County Road 3.25 and Highway 52. Nearby Development No developments are located within one-half mile of the proposed Filly Ridge PUD. Current Property Condition and Historic Drainage Pattern The proposed development consists of approximately 25 acres. The property is currently zoned agriculture. It has historically been utilized for irrigated crop farming. The latest crop harvested off of the ground was irrigated corn. The site drains southeast to northwest. The slope is fairly consistent through most of the site at approximately 1.5 to 2.0 percent with a small portion in the northeast corner of the property at approximately 4.5 percent. The near- surface soil type on the property is predominantly Olney fine sandy loam and Otero sandy loam, which are both hydrologic group B. Two ditches run across the property from southwest to northeast; the Lower Boulder Ditch and Boulder and Weld County Ditch. The buildable lots are located between these two ditches. Area Drainage Description The area drainage is virtually all to the northwest and Boulder Creek, which is located approximately % mile away. The development is protected from offsite drainage by two things: a large hill to the southeast that keeps the majority of the area's drainage diverted to the east and west of the proposed development; and Highway 52, which is considerably higher in elevation than the surrounding grade and therefore diverts what little area may drain towards the development from the southeast. One area drainage is approximately one-half mile to the northeast of the development site and transports stormwater to the northwest and Boulder Creek. The second area drainage is approximately 3/4 mile to the south-southwest and also transports stormwater to the northwest. The confluence of Boulder Creek into St. Vrain Creek is approximately four miles north- northeast. Currently, runoff from the extreme southeastern corner of Filly Ridge PUD enters Lower Boulder Ditch. The main area, containing buildable lots, drains into Boulder and Weld County Ditch. The portion of Filly Ridge PUD north of Boulder and Weld County Ditch (designated as open space) drains to the northwest and eventually into Boulder Creek. The proposed site is not within a 100-year floodplain. A floodplain exists along Boulder Creek and approaches within '/z mile of the site along the old Burlington Northern Railroad line to the northwest. Storm Drainage Report LANDPROfessionals, LLC 3 Filly Ridge PUD 10.30.2003 Off-Site Drainage Affecting Development Off-site drainage will not affect the development as mentioned above. Drainage Design Concept The Filly Ridge PUD drainage concept is to utilize the historic pattern of drainage towards the northwest. Three detention ponds are planned; one each in the southwest corner, northwest corner and northeast corner. The planned road will act as a barrier and divert runoff from the southern most portion toward the west and eventually into the detention pond in the southwest corner of the site. No detention is planned for the area on the south side of Lower Boulder Ditch and the north side of Boulder and Weld County Ditch since no actual development will occur in these areas. One additional pond will be utilized for irrigation purposes. This pond is in the south part of the development, east of the southwest detention pond. Stormwater will flow through this irrigation pond as it goes to the detention pond to the west. The southwest detention pond will be oversized to allow for additional irrigation storage. Included in Appendix A in this report are the following maps: Historic Drainage Map The Historic Drainage Map demonstrates the drainage patterns and drainage basins before development. Storm Drainage Map The Storm Drainage Map demonstrates the proposed stormwater drainage detention and control at Filly Ridge PUD. Outfall Detail Maps The Outfall Detail Maps show the details of the outfall structures, including orifice plate size, trash rack, and pertinent elevations. Area Drainage Map This map is a USGS topographic map showing the location of Filly Ridge PUD, surrounding topography, area drainage swales, and drainage characteristics. Floodplain Map This is the FEMA map locating flood zone areas. Note that no flood zone is located within one-half mile of the subject property. Historic and Developed Flows The 5-year historic, 100-year historic, 5-year developed, and 100-year developed flows were calculated for the development area utilizing the Rational Method. The rainfall intensities were determined from equation RA-3 of the Urban Drainage and Flood Control District (UDFCD) Criteria Manual utilizing the 1-hour point rainfall depth for the development area of 1.40 inches for the five-year storm and 2.70 inches for the 100-year storm (Figures RA-2 and RA-6 respectively). The runoff coefficients were determined utilizing equations RO-6 and RO-7 Storm Drainage Report LANDPROfessionals, LLC 4 Filly Ridge PUD 10.30.2003 from the same manual and utilizing an area weighted calculation. The calculation tables are found in Appendix B and the reference figures and charts are located in Appendix C. The 5-year and 100-year historic flows from Basin 'A' are 0.56 and 2.40 cfs respectively. The 5-year and 100-year developed flows from Basin 'A' do not change, as there is no planned development in that area. The 5-year and 100-year historic flows from Basin 'C' are 1.80 and 15.41 cfs respectively. The developed flows from Basin 'C' do not change, as there is no planned development in that area. Basin 'B' was figured first historically as two basins; B-1 and B-2. Basin B-1 makes up most of the developed area on the west side (14.35 acres) and Basin B-2 makes up a small area (3.31 acres) in the northeast corner of the developed site area. The 5-year historic flows for Basins B-1 and B-2 were calculated to be 4.84 and 1.47 cfs respectively. Therefore, the sub-areas making up Basin B have allowable discharge rates of 0.34 and 0.44 cfs per acre for Basins B-1 and B-2 respectively. The 100-year historic flows for Basins B-1 and B-2 were calculated to be 34.21 and 8.47 cfs respectively. The developed flows for Basin `B' were calculated utilizing three sub-basins (B-1, B-2 & B-3); one basin for each proposed detention pond. The developed 100-year flows for each sub-basin were calculated as follows: B-1, 15.53 cfs; B-2, 12.73 cfs; and B-3, 14.84 cfs. Detention Volume Utilizing the above calculated developed flows, site-specific rainfall intensities, and the allowable discharge rate, detention pond sizes were calculated utilizing the Modified FAA Method from the UDFCD developed spreadsheets. The required detention volumes are 0.48, 0.36 and 0.45 acre-feet for Basins B-1, B-2 and B-3 respectively. The calculation tables are in Appendix B. Irrigation Pond Detention Pond B-lb will also be utilized as a permanent-pool irrigation pond (along with the entire capacity of Pond B-1 a). The permanent pool volume will be approximately 0.57 acre- feet, leaving the remaining capacity for stormwater detention. Swale Design Three grass swales will be utilized to transport stormwater into Detention Ponds B-1, B-2 and B-3. These swales have been designed to carry the flow expected from a 100-year event. Design calculations are in Appendix B. Outfall Design The outfall structures were designed to discharge stormwater at a maximum rate equivalent to the 5-year historic rate. Therefore, the discharge rates for each detention pond were calculated to be as follows: 1.94, 1.94, and 1.64 cfs for B-1, B-2 and B-3 respectively. Each outfall structure will have an orifice plate restricted discharge system. The discharges will be through 12-inch PVC pipe and on the north side of the Boulder and Weld County Ditch. These discharge points will best simulate historic conditions since the ditch company does not allow Storm Drainage Report LANDPROfessionals, LLC 5 Filly Ridge PUD 10.30.2003 discharge into the ditch. Two crossings will be utilized. Ponds B-lb and B-3 will be combined into one crossing, either one larger pipe or two pipes bound together. Orifice plate design calculations are in Appendix B. Maintenance Access Maintenance access will be via the PUD interior road, along the Boulder and Weld County Ditch and the available open space. Conclusion Since Basins 'A' and 'C' have no development planned, no detention is planned for Basin 'A' or 'C'. Three detention ponds are planned for Basin 'B', as shown on the Storm Drainage Map in Appendix A, and sized per the calculations in Appendix B. Discharge points will be on the north side of Boulder and Weld County Ditch, and will be limited to the 5-year historic flow rates. Compliance The planned Filly Ridge PUD site does not lie within a 100-year floodplain. Therefore it is not required to meet any FEMA flood hazard regulations. This report complies with Weld County Code 24-7-120, Storm Drainage Requirements. The Filly Ridge PUD does not lie within the South Weld I-25 Corridor Master Drainage Plan area. ra- Storm Drainage Report LANDPROfessionals, LLC 6 Filly Ridge PUD 10.30.2003 Appendix A • Historic Drainage Map • Storm Drainage Map • Duffel!Detail Maps • Area Drainage Map • Floodplain Map Storm Drainage Report LANDPROfessionals, LLC 7 \� � I 11 ..E No .1 I ..v S - ...----1 — - 4,6 • u BAsiJ c - • — ' 0 ....�^` 6.05 ACRES :: ___ •.. :..G./ 44800 Oa ML�F•- /J1 • — C ykl; 4401 4981— i 4 f L - �� SO�� 0�4 i i I /11 7 i I Imo? 1� / l0 � / ,...... ! e SIN ••$ / /71 7w'no - v 4.35 ACRES i � ' ,/ Mr I\I� / j 1� ,_, e ; , . i / Ito 140 / 4 / q00 / _ — Fl __,,,, • �- 49soo /�� u� / BASIN 'A' '—I i a o f 0.77 ACRE oato y9-- �� 4490 4491 6 5 -H&J-WAY..52_ a too zoo ISieaCI SCALE: 1' = 200' L ANDPROfessionals, LLC FILLY RIDGE PUD 10/30/03 A:`Di RO Architects-Planners-Engineers HISTORIC DRAINAGE MAP D _ I all 1 n hip t ifi �� ei 1 I1 ni g '°h t. N I (.�� A,'L I � �I \ ... h 3 f I '� � I 1 I H. k , `• , I IA I a5 •\i #, lig \• • 1 ) ,, ) . J.1 I - - 1 \ • 1 \il II � � . R i - \., 1:111 4 \• 0 I � ( '.g \ I NI ' ' 11111 v V. v it 1 `. I i• Kl-j v@\rte\ `n\\ \\ \ -- : xx ^,�\ \ 111- G 4 \ • I \ r \ NIIK ; P \ . �� ?_ .\\\ ` \ 1 \ it ti_ c i;i\ i (°44 \:4( -1-14/ I ::: !‘ \ V l4. R. 3.25 ..�•. r 1 r---- \ - r,R ow 8Z l P' 8 [AND PRO RO LANDPROfessionals, LLC FILLY RIDGE PUD10/50/0' Architects-Planners-Engineers STORM DRAINAGE MAP DR-2 I )PROVIDE REµOVABLETRASHRACK OVER E--1 OUTLET (µIN. AREA 5 sq.(l, i.e., 2.5'x2.5'), Q µM. CLEAR SPACE = 5.25" 3:1 µINIµUµ SLOPE _J Q H 12" PVC (FLOW TO JOIN OUTFALL OF 'B 3' POND ) O 0 • J J W < C7 LH O H O >- _ J J co RIPRAP FOR L_ BASIN ' B - 1E31 OUTFALL DETAILS EMERGENCY SPILLWAY z EµBANKµENT CREST Q CONCRETE WEIR (ELEV. = 4976.5) m STRUCTURE U EMERGENCY ,--1 SPILLWAY CREST 1 1 y a C 100 YEAR S. ELEV. = 4975.5 —4 a Ta ro TRASHRACK oI III-III III-I I �. III I i I o I PERMANENT WATER - — _ — — — — _ —I F \OOL ELEVATION (4974.5) — w INVERT`— r-i . = 4974 12PVC 7=1=m=1II III 5I a YEAR ORIFICE PLATE, 9-5/8" 0 OPENING 7II (INVERT ELEV. = 4974.5) CD rri NOTE: TRASH RACK & 3/8° STEEL ORIFICE PLATE TO BE HOT DIP GALVANIZED ANCHOR WITH 3/8" DIA. X 4 1/2" STAINLESS STEEL BOLTS. IMBED BOLTS 3" INTO CONCRETE. CI ecC NOT TO SCALE i 1 M a PROVIDE REµOVABLE TRASHRACK OVER T Q OUTLET (µIN. AREA 3.6 sq.ft., i.e., 2'x2'), PROVIDE TYPE !1 OR BURIED TYPE L µAX. CLEAR SPACE = 5.25" ��•��•�•�•�•�•�•�•�•�� RIPRAP ON SIDES & FRONT OF OUTLET 3:1 µINIµUµ SLOPE ••••••••••••••• TO CONTROL LOCAL EROSION H LIJ o 0 12" PVC � n - — — Ill `C L0 LL •�•� >- - CONCRETE J•••��•�a��7�•�� C" TRICKLE CHANNEL VtA% J m LOCALLY ` z STEEPE ED RIPRAP FOR cn SLOPE EµERGENCY SPILLWAY Q co EµBANKµENT CREST CONCRETE WEIR (ELEV. = 4977.0) STRUCTURE BASIN ' B -2 ' OUTFALL DETAILS U11 I_ 0 EµERGENCY a c SPILLWAY CREST 1 G ro 4 i° 100 YEAR .S. ELEV. = 4976.0 a TRASHRACKI 911=. . .111-"=. . .111=. . .111=. . .111=-. . .11 = w _ _ INVERT OF POND—— I-I�T- Q .n AT OUTLET — — — P4 W INVERT 12pVC Z - = — E . = 4974 —ii—iii—iii—lii " - - - DEPRESS INLET 6" 0 TO PREVENT BACKUP 5-YEAR ORIFICE PLATE, 7-7/16" 0 OPENING OF LOW FLOWS (INVERT ELEV. = 4974.0) a NOTE: TRASH RACK & 3/8" STEEL ORIFICE PLATE TO BE HOT DIP C1 GALVANIZED ANCHOR WITH 3/8" DIA, X 4 1/2" STAINLESS STEEL BOLTS. IMBED BOLTS 3" INTO CONCRETE. �, NOT TO SCALE PROVIDE REMOVABLE TRASHRACK OVER OUTLET o = H (MIN. AREA 4.8 sq.ft., i.e., 2,25'x2.25'), ZT 5, Q PROVIDE TYPE M OR BURIED TYPE L MAX. CLEAR SPACE = 5.25" RIPRAP ON SIDES & FRONT OF OUTLET 3:1 MINIMUM SLOPE TO CONTROL LOCAL EROSION POND 'B-3' & 'B-1b' COMBINED OUTFALL IN ONE PIP _i ,�,� ■■■! OGETHERPVC -FOR CROSSINGSE DITCHD 1W0 12° PIPES w ■■■■■I■ _ 12" PVC _ _ CONCRETE >- TRICKLE CHANNEL I , co LOCALLY L_ - STEEPE ED RIPRAP FOR Z SLOPE EMERGL A NB/SANT CREST CONCRETE WEIR (ELEV. = 4975.5) BASIN ' B -3 ' OUTFALL DETAILS STRUCTURE EMERGENCY JYRESTIIWA C V 100 YEAR W.S. ELEV. = 4974.5 4 TRASHRACKIRTOF POND74 AT OUTLET - - - - - 14 Li; . ��IJVER = 4973 12" PVC I� 2 i—Iil—hill—iii— — - 4 :c"III_ - - - - - - a DEPRESS INLET 6" a TO PREVENT BACKUP 5—YEAR ORIFICE PLATE, 7-7/16" 0 OPENING CO OF LOW FLOWS (INVERT ELEV. = 4973.0) r/ NOTE: TRASH RACK & 3/8" STEEL ORIFICE PLATE TO BE HOT DIP AM I GALVANIZED ANCHOR WITH 3/8" DIA. X 4 1/2" STAINLESS STEEL 0 BOLTS. IMBED BOLTS 3 INTO CONCRETE. .cey NOT TO SCALE b 0° LI 1 1 f 'I• Ns.) =F,/ 1(• . i . . �dt /jS //— 0• � -Li— J " f / R� • , r.-..:._:.:,- l .1.Q' •. am I: !. / a rte... p. t ; t . 's • :4/ / .* „.,::-/ . - _./ see ' �y �.... f -....___..... - —Q_.- Ruda Tden� 41 1 y t, ; / 7.• - --------,-- --/4(6.. '' •�/ / W.C.R.3.25 v. ! rZ 3 !• '✓ / • K . /+ k / II ,....,c .v ` . `,\ / / I ; 1 /`(-\. FILLY RIDGE PUD LOWER • . ‘,,. BOULDER DITCH I _At' ,r i /I • iy..-, �/ j• l`Iumlxyf ax+? I' ._ _. uryrwAt H 1§2. ,i ;ar�� I �` �i/1 i • I it I. . / r ,,...._••••2k91:7-...._____., ---- /,' r i I i j • U r - • (-BOULDEI5$WELD COUNTY DITCH . . I -- ;� • V • ! I / ‘N-W.C.R.3 • 6 .. • /`d' — j i -...____J 0 I. ' • i r r/ • f• r �. � C�-rt�+srON . �. . , ' _ ...... .. ...f :.: .. SIK I a,rrH ;i•;',,, y, GO -....--'' .�'\! - iI ' i9B6 w 4086 �� r+• 1...-.--- ` • � : . . . • . . . 9 , # C..d yes -•'•••••-n,-.. ,• :.h..,__ J:' I Name: ERIE Location: 040.0888035` N 105,03366215`W Date. 10/30/2003 Captlon: FILLY RIDGE PUD Scale-. 1 inch equals 2000 feet Area Drainage Map CoGvn,iht(C);39'.Mantach.tnc. ) ) ) /i LIM 1 �� :) or 1 ° )1/ p t', a =7 APPROXIMATE SCALE r +<-/ 2000 0 2000 FEET I / �/ � 1 t 1 Q II i -Vj NATIONAL FLOOD INSURANCE PROGRAM elf C J rp 4., - # y-i �, L---..--__. S T a SYrxtJr"yW l ——— 1 �� VIII: „ -- — FIRM ,4`' ,,, iqz .1 1 FLOOD INSURANCE RATE MAP 1 30 T _:. I 3a g it `* t 6f#• 4`i i1 f T t Y:.f '' Y �„,, , . tx , , �� WELD / T {c �� LS fk C, i 6' -..is. i rr r � °�� .�� . L sit �c COUNTY, i u 'T"s � e` r — COLORADO 1 ¢ 5 r }`✓�,k .! '+ OaC�O �I III UNINCORPORATED AREA 4tH.-9,„? i r k`< tt4 , _r5 , 4 t9 k se a' : �.• 4, =,-,g- f� 3�P�� o �l co I' I PANEL 850 OF 1075 PANE s NOT.gm.Ea, el - qtr i n m s . � � 0 � � � r U n , 1 Y rxff� A 17, s t hs�"� iiir wl �� ill') 0 O ark "`z-::4 r F�iz: �s S - 5-------/ I I 1 J rte. {tx e d�' [q' s`,> m ':ft n ,y�2 ,�{Ly +'{- 4f �"ay '. l I > e :5 -' -' I�� jr— /1 COMMUNITY-PANEL NUMBER � `tt « o- 32 080266 0850 C ' ,Ia I MAP REVISED: I, -' " �'. • eguldet SEPTEMBER 28. 1982 4+ ₹� / € Sf; [ ✓ L federal emergency management A and r�i ILf LY RIDGE PUD jJ aBnw Li' �` /NINEFA L(' ROAD -fS@t. / - _Hens? /1 " a., - ry f?., + 'y`s''xf l l I 'm / 5\ -- (//1 �a. INC. on FRAME -- ^ - .+-'---i�' r This is an telcial copy of a portion of the show referenced flood map. It :± was extracted using F-MIT On-Line This map does not reelect changes or amendments which may have been made subsequent to the date on the title block. For the latest product information abput National Flood Insurance Program flood maps check'he FEMA Flood Map Store at www.mec.fema.gav Filly Ridge PUD 10.30.2003 Appendix B • Rational Method Calculations • Detention Pond Sizing Calculations • Swale Design Calculations • Orifice Plate Design Calculations Storm Drainage Report LANDPROfessionals, LLC 8 Filly Ridge PUD Drainage Calculations Impervious% Basin'A'Impervious Percentage Basin*B-1'Impervious Percentage Basin'B-2'Impervious Percentage Decimal ` Decimal Decimal Land Use Acres Impervious A•PI Land Use Acres Impervious A•PI Land Use Acres Impervious A'PI Ag Land 0.630 0.02 0.01 Ag Land 5.06 _0.02 0.10 Ag Land 3.46 0.02 0.07 Dirt Roads - 0.40 - Dirt Roads - 0.40 Dirt Roads - 0.40 - Buildings - 0.90 - Buildings 0.20 0.90 0.18 Buildings 0.30 0.90 0.27 Paved Areas 0.140 1.00 0.14 Paved Areas 0.50 1.00 0.50 Paved Areas 0.60 1.00 0 60 Totals 0.770 acres 0.15 Totals 5.76 acres 0.78 Totals 4.36 acres 0.94 0.0012 mi2 0.0090 mi2 0.0068 mil Weighted Impervious Percentage= 19.82% Weighted Impervious Percentage= 13.56% Weighted Impervious Percentage= 21_54°J Basin'B-3'Impervious Percents e Basin'C'Impervious Percentage Decimal Decimal Land Use Acres Impervious A' PI Land Use Acres Impervious A•PI — Ag Land 3.87 0.02 0.08 Ag Land 6.05 0.02 0.12 Dirt Roads 0.40 - Dirt Roads 0.40 - __ Buildings 0.40 0.90 0.36 Buildings 0.90 - Paved Areas 0.60 1.00 0.60 Paved Areas 1.00 - 1 Totals 4.87 acres 1.04 'Totals 6.05 acres 0.12 0.0076 mi2 0.0095 mil II Weighted Impervious Percentage= 21.30% Weighted Impervious Percentage= 2.00% I. LANDPROfessionals, LLC Eric W. Dunker,P.E. Drainage Calculations Filly Ridge PUD r Historic Flows (BASIN 'A') Area Weighting for Runoff Coefficient(Basin'A') Based on Runoff Coefficient estimating equation published by Urbonas,et.al.(1990)&WEF(1998) Basic equation for NRCS Soil Types C&D: Cam„=Kr„+(0.858`1'-0.786*i2+0.774*i+0.04) Basic equation for NRCS Soil Type A: C, =K, +(1.31*ir- 1.44`12+ 1.135`1- 0.121 in which use values for C, >0 Basic equation for NRCS Soil Type B: Ce=(C,, +Cc0)/2 in which: - 1,/100,imperviousness ratio 1, =watershed imperviousness in percent Ca =Runoff Coefficient for NRCS Soil Type A K,1 =Correction factor for C a when the storm retum period is greater than 2-years CAD =Runoff Coefficient for NRCS Soil Types C and D Kco =Correction factor for Co,when the storm return period is greater than 2-years Values of Correction Factors KCoa KA NRCS Storm Return Period Soil Types 2-yr 5-yr 10-yr 25-yr 50-yr 100-yr C 0.00 [-0.10'1+0.11] [-0.18*i+0,21] [-0.28'1+0.33] [-0-33',+0.40] [-039*i+0.46] A 0.00 (-008`1+009] [-0.14*i+0.17] [-0.19*i+0.24] [-0.221+0.28) [-0.25"1+0.32] Sub-Area# Area(Acres) Impervious NRCS Soil Calculated Calculated Calculated Calculated C C A (decimal) Type CA-syr CCD-syr CA-1o0yr CCD-lopyr s s'A Cmo Cioo 1 0:77 0.20 B 0.13 0.26 0.33 0.55 0.20 0.15 0.44 0.34 2 0 0 : 0 0.00 0.15 0.20 0.50 0.00 0.00 0.00 0.00 3 0 0 0 0.00 0.15 0.20 0.50 0.00 0.00 0.00 0.00 4 0, " 0' '0'. 0.00 0.15 0.20 0.50 0.00 0.00 0.00 0.00 5 0 0 0 0.00 0.15 0.20 0.50 0.00 0.00 0.00 0.00 Sum: 0.77 Sum: 0.15 Sum: 0.34 Area-Weighted Runoff Coefficients(sum CA/sum A) Weighted C5= 0.197 Weighted C1oc' 0.441 Proposed Development Area(Filly Ridge PUD)Basin'A' 5-year historic 100-year historic Time of Concentration Time of Concentration Initial Time Initial Time C5 Distance(ft) Slope(%) ti(min) Cs Distance(ft) Slope(%) ti(min) 0.197 150 4.7 11.88 0.197 150 4.7 11.88 Travel Time Travel Time Distance(ft) Slope(%) Velocity time tray Distance(ft) Slope(%) Velocity time tray (ft/sec) (ml Iftlsec) (ml 0 0 1 0.00 0 0 1 0.00 Total time(min) Total time(min) 11.88 11.88 tot length time check (Utilize smaller t) tot length time check (Utilize smaller t) 150 10.83 (((/180)+10) 150 10.83 ((ul ao)+10) P1(1-hour point rainfall depth(inches))= 1.40 P1(1-hour point rainfall depth(inches))_ 2.70 (Figure RA-2,UDFCD) (Figure RA-6,UDFCD) Intensity(Equation RA-3, UDFCD) Intensity(Equation RA-3,UDFCD) 3.67 in/hr 7.07 in/hr Rational Rational Flows Flows Gilds) C factor I(inlhr) A(acres) Q(cfs) C factor I(inlhr) A(acres) 0.56 0.197 3.67 0.77 2.40 0.441 7.07 0.77 LANDPROfessionals,LLC Eric W. Dunker,P.E. Drainage Calculations Filly Ridge PUD p Developed Flows (BASIN 'A') Area Weighting for Runoff Coefficient(Basin A) Based on Runoff Coefficient estimating equation published by Urbonas,et.al.(1990)8 WEF(1998) Basic equation for NRCS Soil Types C 8 D: C,-„=K,,.+ (0.858`13-0.786*i' +0.774*i+0.04) Basic equation for NRCS Soil Type A: C, =K, +(1.31*i3- 1.44.12 + 1.135*i- 0.12) in which use values for C, >0 Basic equation for NRCS Soil Type B: Ca=(CA +Ccol/2 in which. i - /„/100,imperviousness ratio !„ =watershed imperviousness in percent C, =Runoff Coefficient for NRCS Soil Type A K, =Correction factor for C3 when the storm return period is greater than 2-years Cell =Runoff Coefficient for NRCS Soil Types C and D Ka) =Correction factor for Gen when the stonn return period is greater than 2-years Values of Correction Factors Kern KA NRCS Storm Return Period Soil Types 2-yr 5-yr 10-yr 25-yr 50-yr 100-yr C&D 0.00 [-0.10*i+0.11) [-0.18*i+0.21] [-0.28*i+0.33] [-0.33*i+0.40] [-0.39*/+0.46] A 0.00 [-0.op,+009] [-0.14*i+0.17] (-0.19'6+0.24] [-0.22*i+028] [-0.25*/+0.32] Sub-Area# Area(Acres) %Impervious NRCS Soil Calculated Calculated Calculated Calculated C5 C (decimal) Type CA-5yr COD-5yr CA-w0yr Cco-10Oyr s*A C100 Ctno'A 1 0.77 0.20 B 0.13 0.26 0.33 0.55 0.20 0.15 0.44 0.34 2 0 0. 0 0.00 0.15 0.20 0.50 0.00 0.00 0.00 0.00 3 0 0 0 0.00 0.15 0.20 0.50 0.00 0.00 0.00 0.00 4 0 0 0` 0.00 0.15 0.20 0.50 0.00 0.00 0.00 0.00 5 0 0 '< ' 0 0.00 0.15 0.20 0.50 0.00 0.00 0.00 0.00 Sum: 0.77 Sum: 0.15 Sum_ 0.34 Area-Weighted Runoff Coefficients(sum CA/sum A) Weighted Cs= 0.197 Weighted CiOd 0.441 Proposed Development Area(Filly Ridge PUD)Basin'A' 5-year developed 100-year developed Time of Concentration Time of Concentration Initial Time Initial Time Cs Distance(ft) Slope(°/0) ti(min) C5 Distance(ft) Slope(%) ti(min) 0.197 150 -` 4.7 11.88 0.197 150 4.7 11.88 Travel Time Travel Time Distance(ft) Slope(%) Velocity time tray Distance(ft) Slope(%) Velocity time tray • Iftlsec) (m) (ft/sec) (m) 0 ' -O. 1 0.00 0 0 1 0.00 Total time(mini Total time(min) 11.88 11.88 tot length time check (Utilize smaller t) tot length time check (Utilize smaller f) 150 10.83 ((U180)+to) 150 10.83 [(U180)+10) P1{1-hour point rainfall depth(inches)}= 1.40 P1{1-hour point rainfall depth(inches)}= 2.70'. (Figure RA-2,UDFCD) (Figure RA-6,UDFCD) Intensity(Equation RA-3,UDFCD) Intensity(Equation RA-3,UDFCD} 3.67 in/hr 7.07 in/hr Rational Rational Flows Flows Q(cfs) C factor I(in/hr) A(acres) Q(cfs) C factor I(inlhr) A(acres) 0.56 0.197 3.67 0.77 Z40 0.441 7.07 0.77 0.00% Increase of Developed Flow over Historic Flow(Insignificant) LANDPROfessionals,LLC Eric W.Dunker,P.E. Drainage Calculations Filly Ridge PUD n Historic Flows(BASIN 'B-1') Area Weighting for Runoff Coefficient(Basin'B-1') Sub-Area# Area(Acres) %Impervious NRCS Soil Calculated Calculated Calculated Calculated C5 C5'A C100 C100*A (decimal) Type CA-5yr C0 .5yr CA-loeyr CCD-meyr 1 14.353 0.0545 B 0.02 0.18 0.24 0.52 0.10 1.49 0.38 5.47 2 - - 0.00 0.15 0.20 0.50 0.00 0.00 0.00 0.00 3 0.00 0.15 0.20 0.50 0.00 0.00 0.00 0.00 4 0.00 0.15 0.20 0.50 0.00 0.00 0.00 0.00 5 0.00 0.15 0.20 0.50 0.00 0.00 0.00 0.00 Sum: 14.353 Sum: 1.49 Sum: 5.47 Area-Weighted Runoff Coefficients(sum CA/sum A) Weighted C5= 0.104 Weighted C1 : 0.381 Proposed Development Area(Filly Ridge PUD)Basin B-11 5-year Historic 100-year Historic Time of Concentration Time of Concentration Initial Time Initial Time Cs Distance(ft) Slope(%) ti(min) Cs Distance(ft) Slope(%) ti(min) 0.104 559 1.425 37.67 0.104 559 1.425 37.67 Travel Time Travel Time Distance(ft) Slope(%) Velocity time tray Distance(ft) Slope(%) Velocity time tray (ft/sec) (ml (ft/sec) (ml 232 0.13 0.2 19.33 232 0.13 0.2 19.33 Total time(minj Total time(mini 57.00 57.00 tot length time check (Utilize smaller t) tot length time check (Utilize smaller t) 791 14.39 {(L/18o)+10) 791 14.39 ((vivo)+10) Pt(1-hour point rainfall depth(inches))= 1..40 P1(1-hour point rainfall depth(inches))= 2.70 (Figure RA-2,UDFCD) (Figure RA-6,UDFCD) Intensity(Equation RA-3, UDFCDI Intensity(Equation RA-3,UDFCDI 3.24 in/hr 6.25 in/hr Rational Rational Flows Flows Q(cfs) C factor I(inlhr) A(acres) Q(cfs) C factor I(in/hr) A(acres) 4.84 0.104 3.24 14.353 34.21 0.381 6.25 14.353 0.337 cfs per acre allowable discharge rate LANDPROfessionals,LLC Eric W. Dunker,P.E. Drainage Calculations Filly Ridge PUD Historic Flows (BASIN 'B-2') Area Weighting for Runoff Coefficient(Basin 1B-21) Sub-Area# Area(Acres) %Impervious NRCS Soil Calculated Calculated Calculated Calculated Cs Cs`A Clue 0100'A (decimal) Type CA-Syr CCDsrr Gainer CCDloer 1 3.312 .0.0978 8 0.06 0.21 0.27 0.53 0.13 045 0.40 1.33 2 0.00 0.15 0.20 0.50 0.00 o 00 0.00 0.00 3 - 0.00 0.15 0.20 0.50 0.00 0.00 0.00 0.00 4 0.00 0.15 0.20 0.50 0,00 0.00 0.00 0.00 5 0.00 0.15 0.20 0.50 0.00 0,00 0.00 0.00 Sum: 3.312 Sum: 0.45 Sum: 1.33 Area-Weighted Runoff Coefficients(sum CA/sum A) 'Weighted Cs= 0.135 I Weighted Clog, 0.402 1 Proposed Development Area(Filly Ridge PUD)Basin B-2' 5-year Historic 100-year Historic Time of Concentration Time of Concentration Initial Time Initial Time Cs Distance(ft) Slope(%) ti(min) Cs Distance(ft) Slope(%) ti(min) ,i-- 0.135 417 3.45 23.48 0.135 417 3.45 23.48 Travel Time Travel Time Distance(ft) Slope(%) Velocity time tray Distance(ft) Slope(%) Velocity time tray (ft/sec) (fUsec) 283 0,46 0.45 10 48 283 0.46 0.45 10.48 Total time(min) Total time(mini 33.96 33.96 tot length time check (Utilize smallert) tot length time check (Utilize smaller t) 700 13.89 ((u180)+101 700 13.89 ((uleq)+1o) P1(1-hour point rainfall depth(inches))= 1.40 Pt(1-hour point rainfall depth(inches))= 2.70 (Figure RA-2,UDFCD) (Figure RA-6,UDFCD) Intensity(Equation RA-3,UDFCD) Intensity(Equation RA-3,UDFCD) 3.29 in/hr 6.35 in/hr Rational Rational Flows Flows Q(cfs) C factor I(in/hr) A(acres) Q(cfs) C factor I(in/hr) A(acres) 1,47 0.135 3.29 3.312 8.47 0.402 6.35 3.312 0.444 cfs per acre allowable discharge rate LANDPROfessionals, LLC Eric W.Dunker,P.E. Drainage Calculations Filly Ridge PUD Developed Flows (BASIN 'B-1') Area Weighting for Runoff Coefficient(Basin'B-1') Sub-Area# Area(Acres) %Impervious NRCS Soil Calculated Calculated Calculated Calculated C5 C5'A C,00 C100`A (decimal) Type CA-5yr CCD-5yr CA-tooyr CCD-iooyr 1 5.76 0.1356. - B 0.09 0.23 0.30 0.54 0.16 0.92 0.42 2.41 2 0.00 0.15 0.20 0.50 0.00 0.00 0.00 0.00 3 ' 0.00 0.15 0.20 0.50 0.00 0.00 0.00 0.00 4 0.00 0.15 0.20 0.50 0.00 0.00 0.00 0.00 5 0.00 0.15 0.20 0.50 0.00 0.00 0.00 0.00 Sum: 5.76 Sum: 0.92 Sum: 2.41 Area-Weighted Runoff Coefficients(sum CA/sum A) Weighted Cs= 0.159 Weighted C,00: 0.418 Proposed Development Area(Filly Ridge PUD)Basin'8-1' 5-year developed 100-year developed Time of Concentration Time of Concentration Initial Time Initial Time C5 Distance(ft) Slope(%) ti(min) C5 Distance(ft) Slope(%) ti(min) 0.159 320 3 21.00 0.159 320 3 21.00 Travel Time Travel Time Distance(ft) Slope(%) Velocity time tray Distance(ft) Slope(%) Velocity time tray (ft/sec) (ml (ftlsec) (m) 300 1 1.5 3.33 300 1 1.5 3.33 Total time(min) Total time(min) 24.33 24.33 tot length time check (Utilize smeller 0 tot length time check (Utilize smaller0 620 13.44 (0./1a0)+10) 620 13.44 ((U180)+10) P1(1-hour point rainfall depth(inches)}= 1:40 Pt{1-hour point rainfall depth(inches))= 2.70 (Figure RA-2,UDFCD) (Figure RA-6,UDFCD) Intensity(Equation RA-3,UDFCD) Intensity(Equation RA-3,UDFCD) 3.34 in/hr 6.45 in/hr Rational Rational Flows Flows __ __Q(cfs) C factor I(in/hr) A(acres) Q(cfs) C factor I(in/hr) A(acres) 3.07 0.159 3.34 5.76 15.53 0.418 6.45 5.76 LANDPROfessionals,LLC Eric W.Dunker,P.E. Drainage Calculations Filly Ridge PUD Developed Flows (BASIN 'B-2') Area Weighting for Runoff Coefficient(Basin 1B-2') Sub-Area# Area(Acres) %Impervious NRCS Soil Calculated Calculated Calculated Calculated C5 Cs*A C,00 C100*A (decimal) Type CA-Syr C00.5yr CA.,00yr Ccotnoyr 1 4.36 02154 B - 0.14 0.27 0.34 0.55 0.21 0.90 0.45 1.94 2 0.00 0.15 0.20 0.50 0.00 0.00 0.00 0.00 3 0.00 0.15 0.20 0.50 0.00 0.00 0.00 0.00 4 0.00 0.15 0.20 0.50 0.00 0.00 0.00 0.00 5 0.00 0.15 0.20 0.50 0.00 0.00 0.00 0.00 Sum: 4.36 Sum: 0.90 Sum: 1.94 Area-Weighted Runoff Coefficients(sum CA/sum A) Weighted C5= 0.205 Weighted Cron: 0.446 Proposed Development Area(Filly Ridge PUD)Basin'B-2' 5-year developed 100-year developed Time of Concentration Time of Concentration Initial Time Initial Time C5 Distance(ft) Slope(%) ti(min) C5 Distance(ft) Slope(%) ti(min) r-- 0.205 315 2.6 20.78 0.205 315 2.6 20.78 Travel Time Travel Time Distance(ft) Slope(%) Velocity time tray Distance(ft) Slope(%) Velocity time tray Ift/sec) (ml (fUsec) (ml 220 ./:0.25 1 3.67 220 0.25 1 3.67 Total time(min) Total time(min) 24.45 24.45 tot length time check (Utilize smaller t) tot length time check (Utilize smaller I) 535 12.97 {(L/160)+10) 535 12.97 ((Uts0)+10) P,(1-hour point rainfall depth(inches))= 1.40 P,(1-hour point rainfall depth(inches))_. 2.70 (Figure RA-2,UDFCD) (Figure RA-6,UDFCD) Intensity(Equation RA-3, UDFCD) Intensity(Equation RA-3,UDFCD) 3.40 in/hr 6.55 in/hr Rational Rational Flows _ Flows Q(cfs) C factor I(inlhr) A(acres). Q(cfs) C factor I(inlhr) A(acres) 3.04 0.205 3.40 4.36 12/3 0.446 6.55 4.36 LANDPROfessionals,LLC Eric W. Dunker,P.E. Drainage Calculations Filly Ridge PUD Developed Flows (BASIN 'B-3') Area Weighting for Runoff Coefficient(Basin 1B-3') Sub-Area# Area(Acres) %Impervious NRCS Soil Calculated Calculated Calculated Calculated C5 C5`A C+00 0100*A (decimal) Type CA-5yr Cc0-Syr CA-tooyr Cco.moyr 1 4.87 0.213 B - 0.14 0.27 0.34 0.55 0.20 0.99 0.45 2.17 2 0.00 0.15 0.20 0.50 0.00 0.00 0.00 0.00 3 0.00 0.15 0.20 0.50 0.00 0.00 0.00 0.00 4 0.00 0.15 0.20 0.50 0.00 0.00 0.00 0.00 5 0.00 0.15 0.20 0.50 0.00 0.00 0.00 0.00 Sum: 4.87 Sum: 0.99 Sum: 2.17 Area-Weighted Runoff Coefficients(sum CA/sum A) Weighted 05= 0.204 Weighted Ciao. 0.445 Proposed Development Area(Filly Ridge PUD)Basin B-3' 5-year developed 100-year developed Time of Concentration Time of Concentration Initial Time Initial Time C5 Distance(ft) Slope(%) ti(min) C5 Distance(ft) Slope(%) ti(min) 0.204 310. 1.9 22.92 0.204 310 1.9 22.92 Travel Time Travel Time Distance(ft) Slope(%) Velocity time tray Distance(ft) Slope(%) Velocity time tray (ftlsec) (m) (iVsec) (m) 0 0 - 1 0.00 0 0 1 0.00 Total time(min) Total time(min) 22.92 22.92 tot length time check (Utilize smaller t) tot length time check (Utilize smeller 310 11.72 {(L/180)+10) 310 11.72 ((L/1B0)+10) Pt(1-hour point rainfall depth(inches))= 1.40 P1(1-hour point rainfall depth(inches))= 2.70 (Figure RA-2,UDFCD) (Figure RA-6,UDFCD) Intensity(Equation RA-3,UDFCD) Intensity(Equation RA-3.UDFCD) 3.55 in/hr 6.85 in/hr Rational Rational Flows Flows Q(cfs) C factor I(tnlhr) A(acres) Q(cfs) C factor I(in/hr) A(acres) 3.53 0.204 3.55 4.87 14.84 0.445 6.85 4.87 LANDPROfessionals,LLC Eric W. Dunker, P.E. Drainage Calculations Filly Ridge PUD Historic Flows (BASIN 'C') Area Weighting for Runoff Coefficient(Basin'C') %Impervious NRCS Soil Calculated Calculated Calculated Calculated Sub-Area# Area(Acres) decimal T e C C C5 C5"A C100 Coro+A (decimal) yP A-5yr CD-sp CA.t0Uyr CCo-10Oyr 1 6.05 -0.02 B 0.00 0.16 0.22 0.51 0.08 0.49 0.36 2.19 2 0.00 0.15 0.20 0.50 0.00 0.00 0.00 0.00 3 0.00 0.15 0.20 0.50 0.00 0.00 0.00 0.00 4 0.00 0.15 0.20 0.50 0.00 0.00 0.00 0.00 5 0.00 0.15 0.20 0.50 0.00 0.00 0.00 0.00 Sum: 6.05 Sum: 0.49 Sum: 2.19 Area-Weighted Runoff Coefficients(sum CA/sum A) Weighted C5= 0.082 Weighted Ciao' 0.362 Proposed Development Area(Filly Ridge PUD)Basin'C' 5-year historic 100-year historic Time of Concentration Time of Concentration Initial Time Initial Time C5 Distance(ft) Slope(%) ti(min) C5 Distance(ft) Slope(To) ti(min) 0.082 179 10 11.38 0.082 179 10 11.38 Travel Time Travel Time Distance(ft) Slope(%) Velocity time tray Distance(ft) Slope(%) Velocity time tray (ft/sec) (m) (ftlsec) (m) 0 0 1 0.00 0 0 1 0.00 Total time(min) Total time(min) 11.38 11.38 tot length time check (Utilize smaller t) tot length time check (Utilize smaller t) 179 10.99 (0.1180)«t0) 179 10.99 ((um)+10) P1{1-hour point rainfall depth(inches))= 1.40''. P1{1-hour point rainfall depth(inches))= 270 (Figure RA-2,UDFCD) (Figure RA-6,UDFCD) Intensity(Equation RA-3,UDFCD) Intensity(Equation RA-3,UDFCD) 3.65 in/hr 7.03 in/hr Rational Rational Flows Flows Q(cfs) C factor I(inlhr) A(acres) Q(cfs) C factor I(inlhr) A(acres) 1.80 0.082 3.65 6.05 15.41 0.362 7.03 6.05 .•—� LANDPROfessionals,LLC Eric W.Dunker, P.E. Drainage Calculations Filly Ridge PUD n Developed Flows (BASIN 'C') Area Weighting for Runoff Coefficient(Basin'C') Impervious NRCS Soil Calculated Calculated Calculated Calculated Sub-Area# Area(Acres) Cs Cs'A Cum Ctoo'A (decimal) Type CA.5yr CCD-Syr Catooyr CCD-iooyr 1 6.05 0.02 ;B, 0.00 0.16 0.22 0.51 0.08 0 49 0.36 2.19 2 0.00 0.15 0.20 0.50 0.00 0.00 0.00 0.00 3 0.00 0.15 0.20 0.50 0.00 0.00 0.00 0.00 4 0.00 0.15 0.20 0.50 0.00 0.00 0.00 0.00 5 0.00 0.15 0.20 0.50 0.00 0.00 0.00 0.00 Sum: 6.05 Sum: 0.49 Sum: 2.19 Area-Weighted Runoff Coefficients(sum CA/sum A) Weighted C5= 0.082 Weighted C100: 0.362 Proposed Development Area(Filly Ridge PUD)Basin'C' 5-year developed 100-year developed Time of Concentration Time of Concentration Initial Time Initial Time Cs Distance(ft) Slope(%) ti(min) Cs Distance(ft) Slope(%) ti(min) /^ 0.082 179. 10 11.38 0.082 179 10 11.38 Travel Time Travel Time Distance(ft) Slope(%) Velocity time tray Distance(ft) Slope(%) Velocity time tray Iftlsec) (ml (ftlsec) (ml 0 0 1 0.00 0 0 1 0.00 Total time(min) Total time(min) 11.38 11.38 tot length time check (Utilize smaller t) tot length time check (Utilize smaller t) 179 10.99 i(U180)+10) 179 10.99 (0-/100)+10} PI(1-hour point rainfall depth(inches))= 1.40 P,(1-hour point rainfall depth(inches))= 2.70 (Figure RA-2,UDFCD) (Figure RA-6,UDFCD) Intensity(Equation RA-3, UDFCD) Intensity(Equation RA-3,UDFCD) 3.65 in/hr 7.03 in/hr Rational Rational Flows Flows Q(cfs) C factor I(inihr) A(acres) Q(cfs) C factor I(inihr) A(acres) 1.80 0.082 3.65 6.05 1541 0.362 7.03 6.05 0.00% Increase of Developed Flow over Historic Flow(Insignificant) t LANDPROfessionals,LLC Eric W.Dunker,P.E. Filly Ridge PUD-Basin B-1' Drainage Calculations en t4.TIDN VE9t1#ME OS M0Di Efl FAA METH©6 (SeesU$pCM Volume)RunM1ChRPIPI!tor des4Ylpdon of me0104) (For catchments less than 160 acres only. For larger catchments,use hydrograph routing methods) (Note:for catchments larger than 90 acres,CUHP hydrograph and routing are recommended) Design Information(rnpufII Catchment Drainage Imperviousness I,= 14 percent Catchment Drainage Area A= 5 76 acres Predevelopment NRCS Sail Group Type= B A,B,C.or D Return Period for Detention Control T= 100 years(2.5,10,25,50,or 100) Time of Concentration of Watershed Tc= 13 minutes Plowable Uri)Release Rate(See Table A) q= 034 cis/acre One-hour Precipitation P1= 270 inches Design Rainfall BF Formula 1=CV PV(C2•Tcl^C3 Coefficient One C1= 2850 Coefficient Two C2= 10.00 Coefficient Three C3= .0.79 Determination of Average Outflow from the Basin(Calculated): Runoff Coefficient c= 0.42 Inflow Peek Runoff Opin= 15.40 cis Allowable Peak Outflow Rate Op-out= 1.94 cts Ratio of OpOWOp-in Ratio= 0.13 Table A Recommended Unit Flow Release Rate in cfslacre of tributary catchment within UDFCD boundaries. Design Frequency NRCS(SCS)Ny lo�l Go JI A ? B C66 I 2-year 002 obi 004 year 001 0.13 0.1 t��o-''��ar 0.13 0.23 0.30 --- --2syear 0.29 0.41 - 052 50-year 033 636— 0.60 100-year 0.50 _, 0 85 1-00 ^a lfeterminatmn 6f➢eYkRYiahYkguirre11s1n ModK••fi-y 'ethd""— Rain(an duration must be entered In ascending order. Rainfall Rainfall Inflow I Alustment Average I Outflow I Storage Duration Intensity Volume Factor Outflow Volume Volume minutes inches/lir cubic feet cis cubic feel cubic feet inpu) (o1Rput) (output) (outpu) (oupu) )output) (output) 5.00 9.06 6,575 1.00 194 582 5,993 1000 732 10,477 100 1.94 i 1,165 9.312 1500 6.05 13.175 0.95 184 1,656 11,519. 2000 524 15,210 084 1 62 '1.. 1,947 1 13,263 2500 464 16,833 077 149 2238 1111 14,594 3000 4.17 18,177 0.72 1.41 2,530 15647 3500 380 19,322 0.69 1 34 I 2,821 16,502 4000 3.50 20.319 067 1.30 3112 17,207 45.00 325 21,201 065 1.26 3,,403 .17,790 5000 . 3.03 21',992 063 123 3,694 18,298 55.00 2.84 22,709 052 1.21 3,986 15.723 6000 268 23,364 061 119 4,277 19,066 6500 254 23,969 060 1.17 4,568 19401 70.00 2.41 24,529 0.90 1.16 .4,659 19,670 7500 230 25,053 0.59 1.14 5,150 19,902 80.00 ) 220 25,543 058 1.13 5,441 20102 8500 211 26,005 1 0.58 1.12 5,733 20,272 90O0 202 26.441 I, 0.57 1126.024 20,417 95.00 195 26,854 0.51 l 1.11 8,315 20.540 100.00 1.88 2]248 057 1.10 6,606 '. 20,642 105.00 181 27623 056 109 6 89 20,726. I 11000 175 27,982 056 1.09 ]188 20,793 1100 1:70 28,325 0.56 1.08 7,480. j 5 20,846 120.00 1.65 28,655 056 1.08 7,771 20884 12500 160 28,972 055 107 I 8,062 20,910 13000 - 1.55 29.277 055 1.07 8.353 20924 13500 1.51 25.572 0.55 107 , 8,644 20,928 14000 LO 29,85] 0.55 106 8,935 20,922 14500 1.43 30133 055 1.06 I, 9227 20906 150 00 1.40 30,400 0 54 1.06 9,518 20,882 155.00 136 30,659 0.54 105 i 9,809 20,850 16000 ' 1.33 30910 f 0.54 105' I 10,100 20,810 165.00 1.30 31,154 I 0.54 1:05 10,391 20,763 170 00 127 31,392 I 0.54 1.05 1 10.682 20,709 175.00 1.24 31,623 054 105 10,974 20.650 ,....... 180.00 1.22 31,848 I 054 1.04 11,265 20,584 185 00 1.19 32068 10:54 _ 1 04 11,556 1 20,512 Stormwaler Detention Volume(Cubic Feet)_ 20,828 Stormwater Detention Volume(Acre Feel)= 0.480E LANDPROf'spinals,LLC Eric W.Dunker,P.E. Flly Ridge PUD-Basin S-1' Dreinage Celculllons re. Inflow and Outflow Volumes vs. Rainfall Duration Intersection of Modified and FAA Outflow Plots is at maximum detention volume uin.iii=C n::uuuununuuunn.u::■:: Anna 30000 iniiiiii■nnu...iiiiiiiiiiinNrn iiiiiin • ■■■■■■■■■■N■■■■ ■■■■■n■■uur&ill■■■■■■■■N ■N■■N uun u::::::::::::::u' :::::::::::is iuui u 25000 N■N■■■N■■■■■■■■p�i■■■■■■■■■■■■■■■■■■■■■■■■■■■■ m■■■■■■■■■■■■■ta ■■■■■■■■■■■■■■■■■■■■■■■■■■■■■ ■i■iiiiuuuiui uuuiiiiiiiiiiiiiiiiiiiunuuuiini LL 20000 uunIMMENE iiiiiiuunniii■■iiuniuiiiiMMiiiiii um■■■■■lN■■■■■■■■■■■■■■■■■nn■■■■■■■■■ ■■■■■■■ m■■■■ :■■Nn■■■■■■N■■■■■■■N■■m■■■■ ■■■■■upE o ■■■■■ ■■N■■■■■■■m■■■■■■■m■■■■■■■■ ■■■■N■ NONNONANNIONNONNONNONNONNINNONNONNONNINNONIONONIN 15,000 ■■■■ n ■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■N ■■■ IMMO NONMEMONNONNONNONNONNONNONNONNONONNONNEENN MENNEN ■■■1!"■■■N■■■N■N ■ ■■■■■■■■■■■■■■■■■■■■■■■■■■■■■ ■■■I■■■■■■N■■■!■um■■■■■■■■■■■■■■■■■■■■■■■■■■■■ ■■n■■n■■■■■■■■ ■ ■ ■■■■■■■■■■■■■■■■■■■■■■uMnnu 10,000 ■■ ■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■v�titae■■■■■ ■■Nn■■■■■■■■N■■■■■■■■■■■■■■■■■■■■t sflu■■■■■■■ . ■m■■■■N■■■.■■■■■■■■■■n■■n■urr�ai■■■■■■■■■■■■■ NINNINNONONN5000 m■■N■NNEMAINNIONONONNONNONNO n; ■= r ,iii i■■iiniii iin�■ uunn�uu:nn" :u'a uuunuCuuu:■■u■■u.'_uuuni ::uu: uH GR':Iipsuuuuu�u■u■ ■■■ ■■■■■■N■■■■■■■■■■■■■■■■■ 0 ■.' ummo■■■NNinN ■Nnn■Nnn■nmmmm■n■ 0.00 20.00 40.00 60.00 80.00 100.00 120.00 140.00 160.00 180.00 200.00 Duration(Minutes) Inflow Volume —r Modifed Outflow Volume ti—FAA Outflow Volume LANUPROnessionals.LLC Eric W.Dunker.P.E. Filly Ridge PUD-Basin'B-2' Drainage Calculations DETENTION VOLUME BY MODIFIED MA:METHOD (aeeV9ACM yalgma.l Runoff Dh dPieblgldeSoflpdnn of ethgtt) (For catchments less than 160 acres only. For larger catchments,use hydrograph routing methods) (Note:for catchments larger than 90 acres,CUHP hydrograph and routing are recommended) `Design T fbrmataon(Input): Catchment Drainage Imperviousness I,s 22 percent Catchment Drainage Area A= 4.38 acres PredeevelopmeN NRCS Soil Group Type= B A,B,C,or D Return Period for Detention Control T= 100 years(2.5,10,25,50,or 100) Time of Concentration of Watershed Tc= 13 minutes Allowable Unit Release Rate(See Table A) 0= 0.44 cis/acre One-hour Precipitation P1= 2 70 inches Design Rainfall IDF Formula I=Cffi Ptl(C2+Tc)C3 Coefficient One CI= 28.50 Coefficient Two C2= 1000 CoefaeN Three C3= 0.79 Determination of Average Outflow from the Basin(Calculated): Runoff Coefficient C= 0.45 Inflow Peek Runoff Op-in= 12 69 cis Allowable Peak Outflow Rate Op-out= 1.94 ch Ratio of Op-out/OPin Ratio= 0.15 Table A Recommended Unit Row Release Rate in da/acre of tributary catchment rattan UDFCD boindanes. Design Frequency III NRCS(SCS)HytTrologic Soil Grou 2-year f 002 003 004 rear 16year — 013 -! 023 036 25-year - 024 041 052 --- Sb-year 0.33 056 R wear 050 0 100 ,."� r - -mafinnM `aeMlnn rc ma Usf>i'• ,url,: >T' d• - .' Rainfall duration must be entered in ascending order. Rainfall Rainfall Inflow Adiusiment Average Outflow Storage I Duration Intensity Volume Factor Outflow Vobvoee Volume minutes inchesmr chic feet cfs cubic feel cubic feet (input) (output) (output) (MNpu) (output) I (output) (output) 500 9.06 5,332 1.00 194 581 4,752 1000 722 8.497 100 194 1,162 7,335 15.00 5.05 10,685 093 180 1,624 9,061 20OD 5.24 12,336 082 1.60 1,915 10,421 2500 464 13652 076. LO 2,205 I 11.447 3000 4.17 14 742 072 1.39 2,495 12,246 35.00 360 i 15,671 . .0.69 1.33 2,786 12,885 4000 350 I 16;479 0.66 1.28 3,076 13,403 45.00 325 17194 064 1.25 3,367 13,828 5000 3.03 1 17,836 0.63 1.22 3,557 14.179 5500 2.84 18,417 0.62 1.20 3,947 14,470 60O0 268 18,949 061 118 4,230 14,711 6500 254 19,439 060 1.16 4,528 14,911 7000 241 19,894 059 1.15 4,818 15,075 7500 230 20.318 0.59 1.14 1 5,109 15,209 80.00 2.20 20,716 0 58 112 15,399 15,316 8500 2.11 21,090 0.58 112 5,690 15,400 90.00 202 21 444 057 1.11 5,980 15.464 95.00 195 21,779 057 1.10 6,270 ) 15509 100.00 168 22,098 0.56 1.09. 6,561 l 15,538 10500 181 i 22,403 056 1.09 6851 15,551 I 11000 1,75- 22093 056 1,08 7,142 15,552 11500 1.70 22,972 055 ,'108' 7,432 15,540 12000 165 WI 1.07 7,722 15,517 125.00 1.60 23497 0 55 1 07 8 013 15484 13000 9 55 23,744 0.55 146 8,303 15,441 135 00 1.51 23.983 055 1,06 8,593 15.390 14000 147 24,214 I 055 1.06 8,884 15331 145.00 1.43 24.438 I 0.54 105 9,174 15264 15000 1.40 24554 0.54 1.05 9465 15,190 15500 1.36 24,864 054 105 9,755 15,110 16000 133 25,068 0.54 1.05 10,045 15,023 165.00 1.30 25266 054 1.04 10,336 14,931 170.00 127 25,459 054 104 10,626 14,833 175.00 1.24 25,647 0.59 1.04 10,916 14,730 18000 122 i 25,830 0.54 104 11.207 14,623 "rat, 185O0 1.19 26.008 054 _ 104 11,497 14,511 Stonnwater Detention Volume(Cubic Feel)a 15,552 Stormwater Detention Volume(Acre Feet)= 0.3370 LANDPROfesslonals.LLC Enc W.Dunker P b Fily Ridge PUO-Basin'B-2' Drainage Calculations Inflow and Outflow Volumes vs. Rainfall Duration intersection of Modified and FAA Outflow Plots is at maximum detention volume 30,000 ,....... .....................................................................i........................................ 25,000 . _ _ _ gi'-'w - X21. • 20,000 .5, I ri- aw ,, s a A U. tj 15,000 Cl E n . � 10,000 l i S 5,000 Ai'''''' Ai 0 I 0.00 20.00 40.00 60.00 80.00 100.00 120.00 140.00 160.00 180.00 200.00 Duration(Minutes) -le-Inflow Volume -se-Modified Outflow Volume I -1-FAA Outflow Volume i— IANDPROtessiooels.LLC Eric W.Dunker,P E. FIN Ridge PUD-Basin 13-3' Drainage Calculations DETENTION VOLUME 8Y Mf1QlEU FAA:MffTWDO `—, (se*usocmymunwo Runoff chapter;for dosarlptiun of monad) (For catchments less than 160 acres only. For larger catchments,use hydrograph routing methods) (Note:for catchments larger than 90 acres,CUHP hydrograph and routing are recommended) eeslgn Information On➢uf): Catchment Drainage InpeMousness I,= 21 percent Catchment Drainage Area A= 4.87 acres Predeveiopment NRCS Sol Group Type= BA AC or D Return Period for Detention Control T 100 years(2,5,10,25,50,or 100) Time of Concentration of Watershed Tc= 12 minutes Allowable Unit Release Rate(See Table A) is= 0.34 dslacre One-hour Precipitation P1= 2.70 inches Design Rainfall IDF Formula I e CV Pil(C2+Tc)aC3 Coefficient One Cl= 26.50 Coefficient Two C2= 10.00 Coefficient Three C3= 079 Determination of Average Outflow from the Basin(Calculated): Runoff Coeelaenl c= 0.45 Inflow Peak Runoff Op-in= 14 82 cfs Allowable Peek Outflow Rote Op-out= 1 64 cfs Ratio of Op-out/Op-in Ratio= 0.11 J Table A Recommended Unt Flow Release Rate in cfs/acre of tributary catchment within UDFCD boundaries. Design Frequency I NRCS SC5)ydrolo.ic Soil Groff A 0 C6D yea_ a 0 - ,03 •-. 0.d__.. 2 10-ear 013 023 030 25-ear _ _ ' 0.24 041 0.52 ear 0.33 0.56 0.68 7Uyear 0.50 085 ton refl."- u _. dlettYmidatroaof:Detl ntian Voldme;(I,sms)Mod4iesfrA idtflod -.A Rainfall duration must be entered N ascending order. Rainfall Rainfall Inflow Adjustment Average Outflow Storage Duration Intensity Volume Factor Outflow VONme Volume minutes jnchesM cubic feet cfs cubic feet cubic feet pros) (WPM (output) (output) (output) (o1po) (ONput1 500. . 9.06. 5,956 100. 1.84 192. 5,464 1000 7.22 9,490 1.00 164 985 8,506 15.00 6.05 11,935 0.89 1.46 1,316 10,619 20.00 5.24 13,779 0.79 130 1,562. 12,217 2500 464 15249 0,73 1 21 1,808 13441 30.00 4.17 16 456 0 70 1.14 2.054 14.412 3500 360 17,504 0.67 1.10 2,300 15203 4000 350 18407 065 106 2546 15,860 45.00 325 19,206 063 103 2793 16.413 50 00 3 03 19,922 0.62 1 01 3,039 16,883 55.00 284 20.571 0.61 1.00 3265 17,286 6000 268 21,105 0.6D 0.98 3,531 17,634 6500 2.54 21,713 0.59 0.97 3.777 17,935 70.00 241 .22221 058 0.96 4,024 18,197 75.00 2.30 22,695 0.50 0.95 .4,270 18,425 8000 220 23,139 0.57 094 4,516 18623 8500 2.11 23,557 0.57 093. 4,762 18,795 90.00 2.02 23952 057 0.93 5,008 18,944 95.00 1.95 24.327 0.56 0.92 5,254 19,072 10000 188 24083 056 092 5,501 19,183 105.00 181 25023 056 0,91 5747 19,276 110.00 1.75 25,348 055 091 5,993 19.355 115.00 1.70 25,659 0.55 090 6,239. 19.420 120.00 165 25.958 055 090 6,485 19,472 125.00 1 60 26,245 0.55 0.90 6,732 19,514 13000 155 26,522 0.55 0:89 6978 19,544 13500 151 26,789 054 0,89 7,,224 19,565 140.00 147 27047 054 0.89 7,470 19,577 14500 1.43 27,297 0.54 -089 7,716 19,500 15000 140 27.538 0.54 0.86. 7,962 19,578 15500 136 27.773 0.54 0.88 8,209 19,564 16000 133 28001 0.54 0.88 8,455 19,546 165.00 1 30 28222 0 54 0.88 8.701 19,521 170.00 1,27 28437 0.53 088 8,947 19,490 .' 17500 1.24 28,647 0.53 0,88 9,193 19,453 18000 122 28,851 053 0.87 9,439 19,411 i...... 18500 _ 1.19 29,050 0.53 0.87 9,686 19.364 Slonnwater Detention Volume(Cublc Feet)• 19,58(j Stormwatar Detention Volume(Acre Feet)• 0.4495 LANDPROfessionals.LLC Eric W.Dunker.P E. Filly Ridge PUD-Basin'63' Drainage Calculations Inflow and Outflow Volumes vs. Rainfall Duration Intersection of Modified and FAA Outflow Plots is at maximum detention volume 35,000 ___._..._......._.._..,.._..._. . .__. . _.__...__..__..._..__..___._.._. 30,000 -- .. g.H 25,000 It- fit m w mss. , v 20,000 t lo �, o U 4I 7 I 15,000 ' ' M 10,000 � a 4 ..0--ii5,000 - , 0 0.00 20.00 40.00 60.00 80.00 100.00 120.00 140.00 160.00 180.00 200.00 Duration(Minutes) - -Inflow Volume -,t-•Modlfied Outflow Volume t FAA Outflow Volume I- tat- LANDPROfessionals.LLC Eric W.Dunker,P.E. Filly Ridge PUD Drainage Calculations Detention Basin Capacities Basin 'B-la' Surface Area Surface Area @ Incremental Cumulative Elevation @ depth (ft2) depth (Acres) Volume (A.F.) Volume (A.F.) 4,975.5 142 0.00 0.00 0.00 4,976.0 1,625 0.04 0.01 0.01 4,976.5 5,607 0.13 0.04 0.05 4,977.0 11,221 0.26 0.10 0.15 4,977.5 15,523 0.36 0.15 0.30 4,978.0 19,299 0.44 0.20 0.50 4,978.5 23,630 0.54 0.25 0.75 4,979.0 26,149 0.60 0.29 1.03 4,979.5 28,302 0.65 0.31 1.35 4,980.0 30,242 0.69 0.34 1.68 4,980.5 32,151 0.74 0.36 2.04 4,981.0 33,952 0.78 0.38 2.42 Basin 'B-lb' Surface Area Surface Area @ Incremental Cumulative Elevation @ depth (ft2) depth (Acres) Volume (A.F.) Volume (A.F.) 4,972.0 2,426 0.06 0.00 0.00 4,972.5 6,523 0.15 0.05 0.05 4,973.0 9,024 0.21 0.09 0.14 '--, 4,973.5 11,289 0.26 0.12 0.26 4,974.0 13,728 0.32 0.14 0.40 4,974.5 16,352 0.38 0.17 0.57 4,975.0 19,194 0.44 0.20 0.78 4,975.5 22,418 0.51 0.24 1.02 4,976.0 25,319 0.58 0.27 1.29 4,976.5 28,248 0.65 0.31 1.60 Basin 'B-2' Surface Area Surface Area @ Incremental Cumulative Elevation @ depth (ft2) depth (Acres) Volume (A.F.) Volume (A.F.) 4,974.0 7,281 0.17 0.00 0.00 4,974.5 8,616 0.20 0.09 0.09 4,975.0 10,063 0.23 0.11 0.20 4,975.5 11,620 0.27 0.12 0.32 4,976.0 13,288 0.31 0.14 0.47 Basin 'B-3' Surface Area Surface Area @ Incremental Cumulative Elevation @ depth (ft2) depth (Acres) Volume (A.F.) Volume (A.F.) 4,973.0 8,951 0.21 0.00 0.00 4,973.5 11,473 0.26 0.12 0.12 4,974.0 14,336 0.33 0.15 0.27 4,974.5 17,595 0.40 0.18 0.45 LANDPROfessional, LLC Eric W. Dunker, P.E. Filly Ridge PUD - 'B-1' Grass Swale Worksheet for Triangular Channel Project Description Worksheet B-1 Grass Swale-Updated Flow Element Triangular Channel Method Manning's Formula Solve For Discharge Input Data Mannings Coefficient 0.030 Channel Slope 0.010000 ft/ft Depth 1.00 ft Left Side Slope 10.00 H :V Right Side Slope 4.00 H :V Results Discharge 21.66 cfs Flow Area 7.0 ft' Wetted Perimeter 14.17 ft Top Width 14.00 ft Critical Depth 0.90 ft Critical Slope 0.017371 fUft Velocity 3.09 ft/s Velocity Head 0.15 ft Specific Energy 1.15 ft Froude Number 0.77 Flow Type Subcritical Project Engineer: Eric W. Dunker g:\farfrumworkin\drainage\filly ridge.fm2 AgPro Environmental Services LLC FlowMaster v7.0[7.0005] 10/29/03 01:51:58 PM ©Haestad Methods, Inc. 37 Brookside Road Waterbury,CT 06708 USA +1-203-755-1666 Page 1 of 1 Filly Ridge PUD - 'B-2' Grass Swale Worksheet for Triangular Channel Project Description Worksheet B-2 Grass Swale-Updated Flow Element Triangular Channel Method Manning's Formula Solve For Discharge Input Data Mannings Coefficient 0.030 Channel Slope 0.009000 ft/ft Depth 0.70 ft Left Side Slope 6.00 H :V Right Side Slope 10.00 H :V Results Discharge 9.10 cfs Flow Area 3.9 ft2 Wetted Perimeter 11.29 ft Top Width 11.20 ft Critical Depth 0.60 ft Critical Slope 0.019760 ft/ft Velocity 2.32 ft/s Velocity Head 0.08 ft Specific Energy 0.78 ft Froude Number 0.69 Flow Type Subcritical r ,n. Project Engineer: Eric W. Dunker g:\farfrumworkin\drainage\filly ridge.fm2 AgPro Environmental Services LLC FlowMaster v7.0[7 0005] 10/29/03 04:48:13 PM ©Haestad Methods, Inc. 37 Brookside Road Waterbury, CT 06708 USA +1-203-755-1666 Page 1 of 1 Filly Ridge PUD - 'B-3' Grass Swale Worksheet for Triangular Channel Project Description Worksheet B-3 Grass Swale-Updated Flow Element Triangular Channel Method Manning's Formula Solve For Discharge Input Data Mannings Coefficient 0.030 Channel Slope 0.010000 ft/ft Depth 0.70 ft Left Side Slope 6.00 H :V Right Side Slope 10.00 H :V Results Discharge 9.59 cfs Flow Area 3.9 ft2 Wetted Perimeter 11.29 ft Top Width 11.20 ft Critical Depth 0.62 ft Critical Slope 0.019627 ft/ft Velocity 2.45 fUs Velocity Head 0.09 ft Specific Energy 0.79 ft Froude Number 0.73 Flow Type Subcritical Project Engineer Eric W. Dunker g:\farfrumworkin\drainage\filly ridge.fm2 AgPro Environmental Services LLC FlowMaster v7.0[7.0005) 10/29/03 04:48:19 PM ©Haestad Methods, Inc. 37 Brookside Road Waterbury,CT 06708 USA +1-203-755-1666 Page 1 of 1 Filly Ridge PUD Pond 'B-lb' Outfall Design (9-5/8" Orifice) Collection Capacity of Vertical Orifice (Inlet Control) vertical oPening ET Eo flaw Bottom oldie Pond Design Information (Input): Net Opening Area A0= 0.5 sq ft Orifice Coefficient Co = 0.61 Top Elevation of Orifice Opening Area Et = 4975.30 ft Center Elevation of Orifice Opening Eo= 4974.90 ft Calculation of Collection Capacity: Enter water surface elevations in ascending order. Water Collection Surface Capacity Elevation ft cfs (input) (output) start 4974.50 0.00 4974.60 0.00 4974.70 0.00 4974.80 0.00 4974.90 0.00 4975.00 0.00 4975.10 0.00 4975.20 _ 0.00 4975.30 0.00 4975.40 1.76 4975.50 1.93 Filly Ridge Basin B-lb UDFCD Detention.xls Vertical Or 10/30/2003, 3:53 PM Filly Ridge PUD Pond 'B-2' Outfall Design (7-7/16" Orifice) Collection Capacity of Vertical Orifice (Inlet Control) vertical "cuing „ul11 ET Eo flow Bottom of the Pond Design Information (Input): Net Opening Area A" = 0.3 sq ft Orifice Coefficient C"= 0.61 Top Elevation of Orifice Opening Area Er = 4974.62 ft Center Elevation of Orifice Opening Eo = 4974.31 ft Calculation of Collection Capacity: Enter water surface elevations in ascending order. Water Collection Surface Capacity Elevation ft cfs (input) (output) start 4974.00 0.00 4974.20 0.00 4974.40 0.00 4974.60 0.00 4974.80 1.04 4975.00 1.23 4975.20 1.40? 4975.40, 1.55 4975.60 1.69 4975.80 1.81 4976.00 1.93 r Filly Ridge Basin B-2a UDFCD Detention.xls Vertical Or 10/30/2003, 3:52 PM Filly Ridge PUD Pond 'B-3' Outfall Design (7-7/16" Orifice) Collection Capacity of Vertical Orifice (Inlet Control) vertical "ening „iron ET Eo flow ..:.......:..............:.:::..:::::. ..................................... Bottom of the Pond Design Information (Input): Net Opening Area A0 = 0.3 sq ft Orifice Coefficient Co = 0.61 Top Elevation of Orifice Opening Area Et= 4973.62 ft Center Elevation of Orifice Opening E0 = 4973.31 ft Calculation of Collection Capacity: Enter water surface elevations in ascending order. Water Collection Surface Capacity Elevation ft cfs (input) (output) start 4973.00 0.00 4973.10 0.00- 4973.20 0.00 4973.30 0.00 4973.40 0.00 4973.50 0.00 4973.60 0.00 4973.70 0.93 4973.80 1.04 4973.90 1.14 4974.00 1.23 4974.10 1.32 4974.20 1.40 4974.30 1.48 4974.40 1.55 4974.50 1.62 Filly Ridge Basin B-3a UDFCD Detention.xls Vertical Or 10/30/2003, 3:51 PM Filly Ridge PUD 10.30.2003 r Appendix C • Tables and Figures Utilized for Calculations Storm Drainage Report LANDPROfessionals, LLC 9 DRAINAGE CRITERIA MANUAL(V. 1) RAINFALL 4.0 INTENSITY-DURATION CURVES FOR RATIONAL METHOD To develop depth-duration curves or intensity-duration curves for the Rational Method of runoff analysis take the 1-hour depth(s)obtained from Figures RA-1 through RA-6 and multiply by the factors in Table RA-4 to determine rainfall depth and rainfall intensity at each duration. The intensity can then be plotted as illustrated in Figure RA-15. TABLE RA-4 Factors for Preparation of Intensity-Duration Curves Duration (minutes) 5 10 15 30 60 Rainfall Depth at Duration (inches) 0.29P, 0.45P, 0.57P, 0.79P, 1.OP, Intensity(inches per hour) 3.48P1 2.70P1 2.28P1 1.58P1 1.0P, Alternatively, the rainfall intensity for the area within the District can be approximated by the equation: 28.5 P I = oase (RA-3) (lo+ T ) in which: 1= rainfall intensity (inches per hour) P1 = 1-hour point rainfall depth (inches) T,=time of concentration (minutes) 06/2001 RA-6 Urban Drainage and Flood Control District DRAINAGE CRITERIA MANUAL (V. 1) RAINFALL F -1 N I E 'U V F GY W P 68 W P C W i F i3C W F 0`_ h I P eJ W 8 03 N 1. I 4 11`. 14 1.4 '1 ;- I _ I.4 Li E14.11i • / - _ 1 - r II -1I LLL -I_ W_i / CCIIiEF I/ 1 I I - I -.r x - ,I F [F.. rrI, 4 i I4 1 1 L _ ELEEF1 I • F-F CF A w r • I I x FIGURE RA-2 Rainfall Depth-Duration-Frequency: 5-Year, 1-Hour Rainfall 06/2001 RA-14 Urban Drainage and Flood Control District DRAINAGE CRITERIA MANUAL(V. 1) RAINFALL F —I ., a _ n F __ ,. F �.- w M w e :.- p v.-'11;I Milli • \ \ ( , \ , � r "t:1!) � ,} . • Cti.,IT I / f FF, HT- / ti 1, _ / I.El,,.EF i rF F E cEEI F-H E F_H>E ELBEFT \uFE✓ I • ILL F...1EH ,_ \I\ 1 1\ _ 11 —N). FIGURE RA-6 Rainfall Depth-Duration-Frequency: 100-Year, 1-Hour Rainfall 0612001 RA-18 Urban Drainage and Flood Control District DRAINAGE CRITERIA MANUAL(V. 1) RUNOFF r TABLE RO-3 Recommended Percentage Imperviousness Values Land Use or Percentage Surface Characteristics Imperviousness Business: Commercial areas 95 Neighborhood areas 85 Residential: Single-family Multi-unit(detached) 60 Multi-unit(attached) 75 Half-acre lot or larger * Apartments 80 Industrial: Light areas 80 Heavy areas 90 Parks, cemeteries 5 Playgrounds 10 Schools 50 Railroad yard areas 15 Undeveloped Areas: Historic flow analysis 2 Greenbelts, agricultural 2 Off-site flow analysis 45 i'^ (when land use not defined) Streets: Paved 100 Gravel (packed) 40 Drive and walks 90 Roofs 90 Lawns, sandy soil 0 Lawns, clayey soil 0 * See Figures RO-3 through RO-5 for percentage imperviousness. Based in part on the data collected by the District since 1969, an empirical relationship between C and the percentage imperviousness for various storm return periods was developed. Thus, values for C can be determined using the following equations (Urbonas, Guo and Tucker 1990). CA = KA + (1.31i 3 - 1.441 2 + 1.135i-0.12)for CA ≥0, otherwise CA =0 (RO-6) CCD = KCD + (0.8858i3 -0.78612 + 0.774i+ 0.04) (RO-7) CB =(CA + CCD)/2 in which: = % imperviousness/100 expressed as a decimal"(see Table RO-3) 06/2001 RO-9 Urban Drainage and Flood Control District Exhibit G contains oversized Drainage Plan Map Please see original file Hello