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Home My WebLink About20043717.tiff Drainage Design Considerations for Ridgeview P.U.D Change of Zone Submittal Weld County, Colorado August 6, 2004 Prepared for: P&A Turkey Farms, Inc. P.O. Box 22253 Denver, Colorado 80222 Prepared by: Wohnrade Civil Engineers, Inc. 337 W. Main Street Barrington, Illinois 60010 Phone: (847)381-2745, Fax: (847)381-2746 Project Number: 0301.00-PAF A\15(Abhill C�co el- 2004 —3717 111154 s 41Thi Wohnrade Civil Engineers, Inc. 337 W. Main Street Barrington, Illinois 60010 Phone:847-381-2745, Fax:847-381-2746 August 6, 2004 Weld County Department of Planning Services 1555 N. 17th Avenue Greeley, Colorado 80631 Re: Drainage Design Considerations for Ridgeview P.U.D. Change Of Zone Weld County, Colorado Dear Staff: Wohnrade Civil Engineers, Inc. is pleased to submit this drainage study for Ridgeview P.U.D. for your review. This report complies with the storm drainage design and technical criteria defined in Section 24-7-130 of the Weld County Code. We acknowledge that review of this study by Weld County is for general conformance with submittal requirements, current design criteria and standard engineering principles and practices. If you should have any questions or comments as you review this report, please feel free to contact me at your convenience. Sincerely, WO IL ENGINEERS, INC. • ; to,. • . t/v 3Ic \'5 M_ ; . . , , P.E. I a a a TABLE OF CONTENTS VICINITY MAP Page No. I INTRODUCTION 1.1 Objective 1 1.2 Project History and Previous Studies 1 1.3 Mapping and Surveying 1 II SITE LOCATION AND DESCRIPTION 2.1 Site Location 1 2.2 Site Description 1 III HISTORIC CONDITIONS 3.1 Historic Drainage Patterns 2 3.2 Historic Drainage Basins 2 ,r IV DEVELOPED CONDITIONS 4.1 Proposed Site Development 3 4.2 Developed Drainage Basins 3 a 4.3 Developed Drainage Patterns 3 4.4 Detention Pond 1 4 i V DESIGN CRITERIA 5.1 Design References 4 5.2 Hydrologic Criteria 4 5.3 Hydraulic Criteria 4 VI EROSION CONTROL . 6.1 Erosion Control Plan 4 VII CONCLUSIONS 7.1 Compliance with Standards 5 7.2 Variances 5 a REFERENCES 6 s s a a EXHIBITS Exhibit 1 FIRM Title Box Exhibit 2 FIRM Map Panel 645 Exhibit 3 FIRM Map Panel 775 Exhibit 4 Off-site Basin Map Exhibit 5 Typical Section - Local Streets APPENDICES Appendix A: Historic Condition Hydrology Appendix B: Developed Condition Hydrology PLANS Sheet 1/2 Historic Condition Plan Sheet 2/2 Developed Condition Plan #' '°1CINITf MAP FOP.RIDGCVICW P.U.D. 104°38 000' W 104°37 000' W 104°36.000'W WGS84 104°35 000' W ., Jf tL„lk• ,..--..--1 .i may. op -•-= - �3 . ..........• 24 19 0 23 o O' ;.:5 u 4 PI /w��y'� h1 all in Y 1 / 1 \ L i ai � ts 4 Auburn Sch•,• pa �� a_- 6aS • X61? ,,......---- :•• _ �'=T -�.1 o°°i _ - ____••• 26 26 2� _ 30 1r• 464 0•Ci`t° , . >a u,0011 ', 117 _---`4 ±_ (-.."4,..„-___‘.. "co +/ ,,,..7 26 � "� Well• a eldi r! 1.° Auburn J� ,,4 r I I a— — j�°.. c i si. ,d. 4649 ex I WELL COUNTY ROAD 521_/, _ / __ 0 ri 4656 i_____ 1 .�4 j,y a0,` ° �� •' 4. \I RIDGEVIEW P.UI -P. s Dam 3c 1100 a.' �� + L c:J ___ �C� Y Y's_- 3 V ` Re7Te ,••-•.----...... 3— 1710• •' � o \ *I WE1I COUNTY ROAD 49) csa \ a ✓�• +` oa i Z _....,12,,,,,,------'--- t I \, \ _ b r I4 \ 1, 'F �`oo.,' \`N`�i/ - $ - O 0 O ' - ♦ / 0 u9y ::,2.)6(...., •. • --____,._•_,--,• _f - - tai. .• • v - t„....,,,,_. ._-_ •.u - _-_ was a LATHAM �1 E.JVO1R r ; �� ', , , tai C.:-....64 \ L 2 It — \ 0 _te ,, of • i 11 t x a+' '. +/ Z �' - t ••( 40_1 O - 1-1 I. T 4 T 47fC O Oo —sass —�`ia1T ' c t9 •• >`i3 ; ikl_'..^m'y '- --- -1 -,-._- ---. ---- - 00 o' : ��-ter • o t,J 'I J + t__-V .__-.. ` I I' \ �` • of o a ▪ V --_ - • :/ --'`/� L 'mom • ebo - �4 7 y I •aa6 .7 - -�_ .\ 4 Latium f • 104°38 000' W 104°37 000' W 104°36.000'W WGS84 104°35 000' W TN �_ Mitt 10° 10:0 e l 0. , 9�_ LIMO MUMS Map created with TOPO!®®2002 Netiom1Ciwgtephic 1wwwmtiottelgwgtephic-xmllepo i Drainage Design Considerations for Ridgeview P.U.D. Change Of Zone Submittal Weld County, Colorado August 6, 2004 1 . INTRODUCTION 1.1 Objective This study documents the results of a comprehensive hydrologic and hydraulic analysis of both pre and post-development conditions for the proposed Ridgeview P.U.D. development. The proposed development is within a PUD Zone District in Weld County (County) and will be processed by the County thru the specific development guide submittal. 1.2 Project History and Previous Studies There are no know studies that precede this report. 1.3 Mapping and Surveying Field survey information and topographic mapping with a contour interval of 1- foot was obtained by Wohnrade Civil Engineers from King Surveyors, Windsor, Colorado. Additional topography outside of the project boundary was taken from USGS topographic mapping with a ten (10) foot contour interval. II SITE LOCATION AND DESCRIPTION 2.1 Site Location The site is located in the northeast quarter of Section 36, Township 6 North, Range 64 West of the 6th Principal Meridian, Weld County, Colorado. The site is bounded by Weld County Road 52 on the north and Weld County Road 49 on the east (See Vicinity Map.) 2.2 Site Description The Ridgeview P.U.D. site is approximately 126.2 acres and is currently in an Agricultural Zone District. The site is being used for agricultural purposes with a center pivot irrigating a portion of the site. Several oil field structures are located on the site with appurtenant access roads. The proposed area of development is located in the northeast corner of the site at the southwest corner of County Road 49 and County Road 52. The majority of the site will remain in dryland agricultural production. The Gilmore Ditch is located adjacent to the site on the west and flows from south to north. There are two ditch access roads located in the east and west sides of the ditch. There are two existing residences located to the north of the site along County Road 52, and one residence located east of the intersection of County Road 52 and County Road 49. Adjacent property directly east of the site is agricultural. Drainage Design Considerations Wohnrade Civil Engineers, Inc. Ridgeview P.U.D.-Change Of Zone August 6, 2004 Page 2 There is an existing residence and outbuildings located on the east side of the site adjacent to County Road 49. County Road 49 is a paved arterial street and, County Road 52 to the north is a local road with a gravel surface. Soil borings located throughout the site have revealed groundwater at depths ranging from four (4) feet to eight (8) feet below existing grade (see soils report.) Surface soils consist of silty sand and sandy lean clay. The Flood Insurance Rate Maps (FIRM's) from the National Flood Insurance Program have been referenced to determine if the site is located within a regulatory floodplain. FIRM map panels 645 and 775 dated September 28, 1982 verify that the site lies outside of the regulatory floodplain (See Exhibits 1 thru 3.) III. HISTORIC CONDITIONS 3.1 Historic Drainage Patterns The majority of the site (100.6 acres) drains overland from east to west at slopes ranging from 0.76% to 4.55% towards the Gilmore Ditch. Stormwater runoff from a small portion of the site (4.0 acre) drains to the northeast to the intersection of County Roads 49 and 52. Stormwater runoff that reaches this intersection is conveyed over the road and continues to the north. There was no visible evidence of a culvert at this location. There is no stormwater runoff entering the site from offsite basins (see Exhibit 4). 3.2 Historic Drainage Basins The site is has been divided into three historic drainage basins. Two of the basins drain toward the Gilmore Ditch. The third basin drains to the intersection of County Road 49 and County Road 52. Basin H1 (15.6 acres) drains overland from east to west towards the Gilmore Ditch. The 5 and 100-year peak discharges from Basin H1 are 0.3 cfs and 13.2 cfs respectively. The majority of the development will take place within this basin. Basin H2 (85.2 acres) drains overland generally from east to west towards the Gilmore Ditch. The 5 and 100-year peak discharges from Basin H2 are 3.9 cfs and 79.1 cfs respectively. The majority of this basin will remain undisturbed. Basin H3 (4.0 acres) drains overland to the northeast corner of the site to the intersection of County Road 49 and County Road 52. The 5 and 100-year peak discharges from Basin H3 are 1.0 cfs and 5.5 cfs respectively. Drainage Design Considerations Wohnrade Civil Engineers, Inc. Ridgeview P.U.D.-Change Of Zone June 7, 2004 Page 3 VI. DEVELOPED CONDITIONS 4.1 Proposed Site Development The proposed development of the site will consist of 9 single-family estate lots, two outlots of 101.106-acres to be dedicated as Conservation Easements, and 6.535 acres of open space. Site improvements will include a cul-de-sac road, Ridgeview Lane, with roadside ditches and a potable water distribution system. It is questionable whether or not County Road 52 will be paved from Ridgeview Lane to County Road 49. There is also the potential for the site to be served by a dual water system for both domestic potable usage and, raw water for irrigation purposes. It is anticipated that homes built in the Ridgeview P.U.D. development will have full basements. Due to groundwater encountered on the site, each lot will be evaluated to ensure that the bottom of the foundation footer is a minimum of three (3) feet above the groundwater elevations measured on February 25, 2000. 4.2 Developed Drainage Basins The site has been divided into three (3) developed basins. Runoff from roughly 14.6 acres of the Ridgeview P.U.D. site will be routed to an on-site detention pond (Pond 1) located in the northwest corner of the site, adjacent to the Gilmore Ditch (See Sheet 2/2.) Developed runoff from the 100- year storm will be released at a 5-year historic rate into the Gilmore Ditch. 4.3 Developed Drainage Patterns The overall drainage pattern of the site will remain unchanged from pre to post- development conditions. Basin 1 (14.6 acres) will drain overland and in roadside ditches to Detention Pond 1. The peak 5- and 100-year discharges at Design Point 1 are 2.6 and 16.5 cfs respectively. Basin 2 (86.2 acres) will continue to drain overland towards the Gilmore Ditch. The peak 5- and 100-year discharges at Design Point 2 are 4.0 and 80.0 cfs respectively. Basin 3 (4.0 acres) will drain overland to the northeast corner of the site to the intersection of County Road 49 and County Road 52. The peak 5- and 100-year discharges at Design Point 3 are 0.8 and 5.3 cfs respectively. Drainage Design Considerations Wohnrade Civil Engineers, Inc. Ridgeview P.U.D.-Change Of Zone June 7, 2004 Page 4 4.4 Detention Pond 1 Detention Pond 1 is located in the northwest corner of the site adjacent to the Gilmore Ditch. This pond will serve as a detention facility for the developed portion of the Ridgeview P.U.D. site. The 100-year peak discharge from the developed site will be released at a historic 5-year rate thru a proposed circular orifice. Detained flows are intended to be released to the Gilmore Ditch over a 72 hour period if possible. The actual release rate and duration will be confirmed during the Final Plat design phase. V. DESIGN CRITERIA 5.1 Design References Drainage criteria outlined in the Storm Drainage Criteria Manual by the Urban Drainage and Flood Control District (Reference 1), has been referenced in the preparation of this study. 5.2 Hydrologic Criteria Due to the relatively small basin size the Rational Method has been used to estimate peak stormwater runoff from the project site. Calculations made as part of this investigation along with other supporting material, are contained in Appendix A. An initial 5-year design storm and, major 100-year design storm have been used to evaluate the proposed drainage system. Rainfall intensity data for the Rational Method has been taken from IDF equations generated specifically for the Ridgeview P.U.D. site by the computer program "Watershed Modeling" by Eagle Point software. Input of precipitation amounts for the generation of intensity equations have been taken from the NOAA Atlas 2, Volume III- Colorado. 5.3 Hydraulic Criteria Where applicable, the following computer models have been utilized: • The computer program "Flowmaster" has been used to analyze the capacity of proposed swales; • The computer model "HY8" by the U.S. Department of Transportation, Federal Highway Administration has been used to analyze proposed culverts. VI. EROSION CONTROL 6.1 Erosion Control Plan The proposed rainfall erosion control plan during construction will consist of temporary structural erosion control measures. Silt fencing will be installed along the top of bank on the east side of the Gilmore Ditch to prevent sediment migration. Permanent vegetative erosion control will be used in conjunction with Drainage Design Considerations Wohnrade Civil Engineers, Inc. Ridgeview P.U.D.-Change Of Zone June 7, 2004 Page 5 landscaping surrounding future residences. Permanent revegetation of areas disturbed by construction will be the responsibility of the contractor. Permanent riprap will also be provided at the outlet of Pond 1. VII. CONCLUSIONS 7.1 Compliance with Standards All applicable drainage criteria have been complied with in accordance with the "Weld County Code". The proposed drainage improvements do not adversely impact surrounding properties. This study conforms to the guidelines specified in Section 27-6-50, paragraph B, item 7, of the Weld County Code. 7.2 Variances No variances are requested as part of this development. Drainage Design Considerations Wohnrade Civil Engineers, Inc. Ridgeview P.U.D.-Change Of Zone June 7, 2004 Page 6 REFERENCES 1) Urban Storm Drainage Criteria Manual, Urban Drainage and Flood Control District, Wright McLaughlin Engineers, Denver, Colorado, March, 1969. r 1 i 1 1 1 1 1 1 1 1 i (- .-. I +�iF`F+l I ' At QN rl.RUD INSURANCE PR4RRAAI tf•.i I `'` NATIONAR FLOOD INSURANCE PRr RANI ; , _.--_ IIII'I I ,,► ►',lE'!III' ►' FIRM j R. ,..,ii,lf;E= FIRM.10,;,,iii,,, , ,. i! 1,, s � ' Ilillr: !ii!:1,'.ii l.'' FLOOD INSURANCE RATE MAP 1 '1'.I'f{ili,' FLOOD INSURANCE RATE MAP t ip!}Illt € t t•,y ! ' IS! t i ,1,.•!!+f��i'if I ',1 E ) I..,I4 F� ;I �rIll'1` WELD i `i !i .'i.!1 'W'ELD �I'�FWill I , f4 �l,iri., .i COLORADC3 '�; t COLORADO! : ,;, I` UNLN'GORPO f9'3'EI3 AREA UNINCORPORATED i ,: f 1 4 1:. ,,i 1 I t li l,,;I`+l l'',ii;1 I PANEL 645 OF 1075 ! yI11i,F. r t .,�1 PAHEf. 775 OF 1075 fF+ tE. i I Il,;_ I 1'•, iSFE MAP'F•;+Ur }:FOR PAti �'S•.:�-. ^„PINT(:'.r, S ( '�II �f SF:'@.VIA.'rtti L"f y. - {1...: t .- i �jsF,lw s 3 i !`if 1•,`'$I i� i I I'F;(I k'� f 1 S, F �; ?iilll III+ tyii eiei .,,IfII• I h[,III I {i ` : ,I 1NIa ! ,,Il I r `'l !iii;t! 4 I II. 10101,d;,:1;;;iti . j,�Gi -lilt 1:.IItt t '!', • i ,,.,� COMMUNITY-PANEL NUMBER I 1� RMMUNtT' PANE€ NUMBER I I;,'1 080266 0645 � `�''` "� 48126 0775 C t: p,i l 1 k' ii (1' R ' MAP REVISED: !;., i' ;", MAP REVISED: IIii' SEPTEMBER 28: 1982 ; .�� SEPTEMBER 2.8, 1982 a�' 'I f !, x { 1.Y'. t6clarttc emergency rnHrt3pemor,t i;pena: I l i'.!,1:, ''II' federal imlerpflnc arWls nt spency r S�f' i:'''.1 ,i,! i ...__________- - ._- ) PAF-i 030. .00I RIDGEVIEW P.U.D. WOHNRADE CIVIL ENGINEERS, INC. 1 --NDDate:Date: 05/01/04 Sheet EXHIBIT 1 2695 W. E ntioxi orad. Blvd., Suite 1,0 S * Loveland, Cold 80538 A. Phone:N.A. (970)667-4995. Fax: (970)667-4984 Designed By: FIRM TITLE BOX !� 5 MBW Sheets/ di - . i _ UNIT I (' I mil-f'.�i s. I I I t6 I L I i • f` - p � 1 • , 1 iJ ., v tit i �" .` .....-..1 r `�t , f . I �4 P&A TURKEY , j •Kr. r FARM PUD co - ---___...._...-__�..._. • _t. ___...__.... ................_..._...______. ...__...____..._, REFERENCE. FLOOD INSURANCE RATE MAP, WELD COUNTY COLORADO, PANEL 845 OF 1075, MAP REVISED \ SEPTEMBER 28, 1982. Itea: 030 �� RIDGEVIEW P.U.D. i 2 Date: - WOHNRADE CIVIL ENGINEERS, INC. 05/01/04 Sheet EXHIBIT 2 2695 W. E ar Blvd. Sufic ,10 Scale: Loveland, Coloradolorad o, 80538 / N.A. Phone: (970)667-4995, Fax: (970)667-4984 Designed sined By: FIRM MAP PANEL 645 .../ 5 MOW k She II 1- I I . . TURKEY FARM PUD • I I • I i I m ill ill REFERENCE. FLOOD INSURANCE RATE MAP, WELD COUNTY COLORADO, PANEL 775 OF 1075, MAP REVISED N SEPTEMBER 28, 1982. Ia�wt as0,.o0 RIDGEVIEW P.U.D. WOHNRADE CIVIL ENGINEERS, INC. he 1 Date: 05/01/04 Sheet EXHIBIT 3 2695 W. Eisenhoweroloro. 81v3.. Suite 110 i Scale: Lovelond, Colorado. 80538 � di NA Phone: (970)667-4995, Fax: (970)667-4984 Designed By: FIRM MAP PANEL 775 !� hee at/ di 1 (....... ,. p.--- e.w.«. ,.M lPINAM I \ r-ss.,..., \ . IIIIIIIIMOMINIMM 4110.1111111111.0. ---,....r44-3 ..,--- ... \ ... ......... . . I . - . ../G r ar. ,,t.'"* :,....14,, . • �'' _ —� r� � I r ------ __- - i1.4 '> 1 1 . r'• �r 1/ lki• ‘•. \ // . 1 . t ti i �`.-' it I \.. ., .., T 0 i wri- le I ! f �• �. C I es %. 1 III ......--) I1.�0 RIDGEVIEW P.U.D. 4 1 oats: WOHNRADE CIVIL ENGINEERS, INC. 05/01/04 Sheet 2695 W. Eisenhower Blvd., Suite 110 Scale: EXHIBIT 4 Loveland, Dorado'80538 I NIB Phone: (970)667-4995, Fax: (970)667-4984 .. Designed By: OFF-SITE BASINS5 .1 Sheehy 11 I I I 1 I R.O.W. R.O.W. 60'-0" 30'-0" - I E.O.P. I E.O.P. F 24'-0" t 4. 4' t SHOULDER SHOULDER I -8'-0" -0'-- 12'-0" 12'-0" - -6'-0" -02.- 4:1 MAX 2% WAIN. 2Z M IN. I , SWALES AS REQUIRED 1 BITUMINOUS ASPHALT PAVEMENT (THICKNESS TO BE DETERMINED IN FINAL DESIGN) GRAVEL SHOULDER (SPECIFICATIONS TO BE DETERMINED IN FINAL DESIGN) GRAVEL BASE COARSE OR FULL DEPTH ASPHALT I (THICKNESS TO BE DETERMINED IN FINAL DESIGN) NOTE: PAVEMENT SECTION TO BE DESIGNED BY SOILS ENGINEER AND APPROVED BY COUNTY ENGINEER PRIOR TO CONSTRUCTION I TYPICAL SECTION - LOCAL ROADWAY 24' PAVEMENT W/ 4' SHOULDERS NOT TO SCALE I I I 1 PI ':"`t + RIDGEVIEW P.U.D. WOHNRADE CIVIL ENGINEERS, INC. C 5 \Date: 05/01/04 Sheet 26EXHIBIT 5 Lov5eland, W. EisenhColorado, Blvd., Suits 110 j Scale: 80538NA i Designed BY: TYPICAL STREET SECTION Phone: (970)667-4995, fax: (970)667-4984 i� 5 "B" Sheet J I Historic Condition - 5 Year Composite Runoff Coefficient Calculations Character of Surface Runoff Project: Ridgeview P.U.D. Coefficient Calculations By:M. Wohnrade Streets:Paved 0.88 Date:April 20, 2004 Streets: Gravel 0.45 Drives and Walks 0.87 Roofs 0.85 Undeveloped Areas 0.01 Runoff Coefficients are taken from the Town of Windsor Storm Drainage Design Criteria Manual,Table 3-1 Basin Basin Area of Area of Area of Area of Roofs Area of Weighted ID Area Streets: Streets: Concrete Undeveloped Runoff Paved Gravel Lawns, Sandy Soil Coefficient (Acres) (Acres) (Acres) (Acres) (Acres) (Acres) H1 15.6 0.00 0.00 0.00 0.00 15.60 0.01 H2 85.2 0.94 0.00 0.00 0.00 84.26 0.02 H3 4.0 0.30 0.00 0.02 0.06 3.62 0.09 1 Historic Condition - 100 Year Composite Runoff Coefficient Calculations Character of Surface Runoff Project: Ridgeview P.U.D. Coefficient Calculations By:M. Wohnrade Streets:Paved 0.93 Date:April 20, 2004 Streets: Gravel 0.60 Drives and Walks 0.89 Roofs 0.90 Undeveloped Areas 0.20 Runoff Coefficients are taken from the Town of Windsor Storm Drainage Design Criteria Manual, Table 3-1 Basin Basin Area of Area of Area of Area of Roofs Area of Weighted ID Area Streets: Streets: Concrete Undeveloped Runoff Paved Gravel Lawns,Sandy Soil Coefficient (Acres) (Acres) (Acres) (Acres) (Acres) (Acres) H1 15.6 0.00 0.00 0.00 0.00 15.60 0.20 H2 85.2 0.94 0.00 0.00 0.00 84.26 0.21 H3 4.0 0.30 0.00 0.02 0.06 3.62 0.27 S:\PROJECTS\PAF\Drng\ChangeOfZone 20041Paf-HistC.wpd Wohnrade Civil Engineers, Inc. 1 I 1 I I . I I . 1 1 k ► . I _ — & -s. I . I a t-3 l___ s II I . s i f. Historic Condition: 5-yr Runoff Computations Weld County, Colorado, Intensity, (i)taken from intensity formula Overland Flow, Time of Concentration: for P&A Turkey Farm, i=40.20/(Tc+9.12)°78 Ti= 1.8(1.1-05)L1'2/S1/3 Velocity, (V)taken from Figure 3-1 Rational Equation: Q= ciA Gutter/Swale Flow, Time of Concentration: T, L/60V Calculations By: M. Wohnrade Project: Ridgeview P.U.D. T0=T, +T, Date: April 20, 2004 Upstream Overland Flow Gutter Flow Swale Flow Time of Design Basins Concentration Area,A Runoff Point (acres) Coefficient Length,L Slope,S T, Length,L Slope,S Velocity.V T, Length,L Slope,S Velocity,V T T Intensity.i Flow,O T, c C, (ft) (%) (min) (ft) (%) (fps) (min) (ft) (%) (fps) c,, ,,,,,,, (infhr) (cfs) H1 H1 0.0 156 0.01 0.01 400 2.3 28 7 0.0 0.0 0.00 0 0 651.0 3.60 3.86 2.8 32.5 2 19 0.3 H2 H2 0 0 85.2 0.02 0.01 400 3.6 25.6 0.0 0.0 0.00 0 0 909.0 2.80 3.28 4.8 30.2 2 29 3.9 H3 H3 0.0 _ 4.0 0.09 0.01 361 4.0 23.6 0.0 0.0 0.00 0.0 0.0 0.00 0.00 0.0 23 6 2 65 1.0 S:IPROJECTSIPAF\Dmg\ChangeOfZone 20041Paf-HistQ.wpd Page 1 of 2 Wohnrade Civil Engineers,Inc. Ir b. I _. l_ _ I l _ I l l I I I l t_ _:2 b._, i. I l It_- I, l 4 Historic Condition: 100-yr Runoff Computations Weld County, Colorado, Intensity, (i)taken from intensity formula Overland Flow, Time of Concentration: for P&A Turkey Farm, i =77.54/(T0+9.12)°.78 T,= 1.8(1.1-05)L112/S1'3 Velocity, (V)taken from Figure 3-1 Rational Equation: Q=ciA Gutter/Swale Flow, Time of Concentration: T,= L/60V Calculations By: M. Wohnrade Project: Ridgeview P.U.D. Tc=T, +Tt Date: April 20, 2004 Upstream Overland Flow Gutter Flow Swale Flow Time of Design Basins Concentration Area,A Runoff Point (acres) Coefficient Length,L Slope,S T, Length,L Slope,S Velocity,V T, Length,L Slope,S Velocity,V T. T Intensity,i Flow.Q T, c C, (ft) (%) (min) (ft) (%) (fps) (min) (ft) (%) (fps) ,.., ,,Nei (infir) (cfs) H1 H1 0 0 15.6 D.20 0.01 400 2.3 29 7 0 0 0.0 0.00 0.0 651.0 3.60 3.86 2.8 32.5 4.23 13.2 H2 H2 0 0 85.2 0.21 0.01 400 3.6 25 6 0 0 0.0 0.00 0.0 909.0 2.80 3.28 4 6 30.2 4.42 79.1 H3 H3 0 0 4.0 0.27 0.01 361 4.0 23.6 0 0 0.0 0.00 0 0 0.0 0.00 0.00 0.0 23 6 5.11 5.5 S:\PROJECTS\PAF\Dmg\ChangeOfZone 2004\Paf-HistQ.wpd Page 2 of 2 Wohnrade Civil Engineers,Inc. 1 ,---- Table 3-1 IRECOMMENDED RUNOFF COEFFICIENTS AND PERCENT IMPERVIOUS I Runoff Coefficients Storm Frequency Land Use or Percent Surface Characteristics Impervious 2 5 10 100 I Business: Commercial Areas 95 .87 .87 .88 .89 1 Neighborhood Areas 70 .60 .65 .70 .80 Residential: Single-Family * .40 .45 .50 .60 li Multi-Unit(detached) 50 .45 .50 .70 Multi-Unit(attached) 70 .60 .65 .70 .80 % Acre Lots or Larger .30 .35 .40 .60 Apartments 70 .65 .70 .70 .80 I Industrial: Light Areas 80 .71 .72 .76 .82 IHeavy Areas 90 .80 .80 .85 .90 Parks. Cemeteries: 7 .10 .18 .25 .45 Iplaygrounds: 13 .15 .20 .30 .50 Schools: 50 .45 .50 .60 .70 IRailroad Yard Areas: 20 .20 .25 .35 .45 Undeveloped Areas: I Historic Flow Analysis, 2 (See Lawns) G reenbelts, Agriculture, Offsite Flow Analysis 45 .43 .47 .55 .65 (When land use not defined) IStreets: Paved 100 .87 .88 .90 .93 I Gravel (Packed) 40 .40 .45 .50 .60 Drives and Walks; 96 .87 .87 .88 .89 Roofs: 90 .80 .85 .90 .90 de Lawns, Sandy Soil 0 .00 .01 .05 .20 ILawns, Clayey Soil 0 .05 .15 .25 .50 * See Figure 2-1 for percent impervious. 11-1-90 URBAN DRAINAGE AND FLOOD CONTROI DISTRICT ---) PAF: 0301.00 TABLE 3-1 Dote: WOHNRADE CIVIL ENGINEERS, INC. 09/22/03 Sheet RATIONAL METHOD 2695 vel W. Eisenhower oratio, Blv3..Suite 110 Scale: Loveland, Colorado, 80538 NA Phone: (970)667-4995, Foe: (970)667-4984 I� 1 DNesigned By: RUNOFF COEFFICIENTS / .Sheetsj di 1 IIUser Name: Mary Date: 06-08-02 Project: P&A Turkey Farm Time: 07:19:06 IINetwork: 00 - Page: 1 Rainfall Report IIRainfall Type Western Rainfall Library P&A Turkey Farm IWestern Precipitation I 2yr/6hr 1.40 in 2yr/24hr 1.70 in 100yr/6hr 3.40 in 100yr/24hr 3.80 in IIElevation 4767.00 llRainfall Intensity (in/hr) 5 min 15 min 30 min 60 min 6 hr 24 hr 2 yr 3.60 2.36 1.64 1.04 0.23 0.07 II5 yr 5.14 3.37 2.34 1.48 0.31 0.09 10 yr 6.17 4.04 2.80 1.77 0.37 0.11 25 yr 7.51 4.92 3.41 2.16 0.44 0.12 II 50 yr 8.74 5.73 3.97 2.51 0.50 0.14 100 yr 9.92 6. 50 4. 50 2.85 0.57 0.16 I BDE Values Intensity = B/(Tc + D)AE B D E X Y 2 yr 28.16 9.12 0.78 0.00 0.00 Isyr 40.20 9.12 0.78 0.00 0.00 10 yr 48.23 9.12 0.78 0.00 0.00 25 yr 58.67 9.12 0.78 0.00 0.00 II 50 yr 68.30 9.12 0.78 0.00 0.00 100 yr 77.54 9.12 0.78 0.00 0.00 1 1 !I II :l tj Ir I S � IA. 1 1 1 aE) i'7 a. n 2 D n a r1 itt JrQ .. fcr I i 1 • I I • Average_ (ttisec) IEQUATION FOR FIGURE 3-1: PAVED: V=16.1345(s)0.5 UNPAVED: V=20.3282(s)°5 s= slope in ft/ft ---) jZgectLiol.c.3 FIGURE 3-1 AVERAGE VELOCITIES WOHNRADE CIVIL ENGINEERS, INC. 1 09/22/03 Sheet 1 2695 W. Eisenhower Bvd., Suite 110 Scale: FOR SHALLOW di NA Phone:(9 Colorado.67-4995.;ox: (970)687-4984 I� J Designed By: CONCENTRATED FLOW 1 NA \Sheets.,/ Developed Condition - 5 Year Composite Runoff Coefficient Calculations Character of Surface Runoff Project: Ridgeview P.U.D. Coefficient Calculations By:M. Wohnrade Streets: Paved 0.88 Date:April 20, 2004 Streets: Gravel 0.45 Drives and Walks 0.87 Roofs 0.85 Undeveloped Areas 0.01 Runoff Coefficients are taken from the Town of Windsor Storm Drainage Design Criteria Manual,Table 3-1 Basin Basin Area of Area of Area of Area of Roofs Area of Weighted ID Area Streets: Streets: Concrete Undeveloped Runoff Paved Gravel Lawns,Sandy Soil Coefficient (Acres) (Acres) (Acres) (Acres) (Acres) (Acres) 1 14.6 0.53 0.55 0.00 0.31 13.21 0.08 I 2 86.2 0.94 0.00 0.00 0.04 85.22 0.02 3 4.0 0.30 0.00 0.02 0.02 3.66 0.08 I Developed Condition - 100 Year Composite Runoff Coefficient Calculations Character of Surface Runoff Project: Ridgeview P.U.D. Coefficient Calculations By:M. Wohnrade Streets:Paved 0.93 Date:April 20, 2004 Streets: Gravel 0.60 kil Drives and Walks 0.89 Roofs 0.90 U Undeveloped Areas 0.20 Runoff Coefficients are taken from the Town of Windsor Storm Drainage Design Criteria Manual,Table 3-1 ill Basin Basin Area of Area of Area of Area of Roofs Area of Weighted ID Area Streets: Streets: Concrete Undeveloped Runoff Paved Gravel Lawns,Sandy Soil Coefficient (Acres) (Acres) (Acres) (Acres) (Acres) (Acres) 1 14.6 0.53 0.55 0.00 0.31 13.21 0.26 2 86.2 0.94 0.00 0.00 0.04 85.22 0.21 I 3 4.0 0.30 0.00 0.02 0.02 3.66 0.26 6 S:\PROJECTS\PAF\Drng\ChangeOfZone 2004\Paf-DevC.wpd Wohnrade Civil Engineers, Inc. II 1 1 . k k I I Ii i _ I __ b Its _ I k _ I— - II_ _ I . II _ k . It Developed Condition: 5-yr Runoff Computations Weld County, Colorado, Intensity, (i)taken from intensity formula Overland Flow, Time of Concentration: for P&A Turkey Farm, i=40.20/(Tc+9.12)0.'6 Ti= 1.8(1.1-05)L1'2/S113 Velocity, (V)taken from Figure 3-1 Rational Equation: Q=ciA Gutter/Swale Flow, Time of Concentration: T,= L/60V Calculations By: M. Wohnrade Project: Ridgeview P.U.D. Tc= Ti+ Tt Date: April 20, 2004 Upstream Overland Flow Gutter Flow Swale Flow Time of Design Basins Concentration Area,A Runoff Point (acres) Coefficient Length,L Slope,S T, Length,L Slope,S Velocity,V T, Length.L Slope,S Velocity,V T -1, Intensity,' Flow,Q T c C, (ft) (%) (min) (ft) (%) (fps) (min) (ft) (%) (fps) in/hr (cfs) 1 1 0 0 14.6 0.08 0.01 250 2.9 21 6 0.0 0.0 0.00 0.0 1446.0 1.61 2.58 9.3 31.1 2.25 2.6 2 2 0.0 86.2 0.02 0.01 400 3.6 25.6 0.0 0.0 0.00 0.0 909.0 2.60 3.28 4.6 30.2 2.29 4.0 3 3 0 0 4.0 0.08 0.01 361 4.0 23.6 0.0 0.0 0.00 0 0 0.0 0.00 0.00 0.0 23.6 2.65 0.8 S:IPROJECTSIPAF\DrnglchangeOfZone 20041Paf•DevQ.wpd Page 1 of 2 Wohnrade Civil Engineers, Inc. Developed Condition: 100-yr Runoff Computations Weld County, Colorado, Intensity, (i)taken from intensity formula Overland Flow, Time of Concentration: for PM Turkey Farm, i =77.54/(T0+9.12)°.78 T;= 1.8(1.1-05)L1'2/S11 Velocity, (V)taken from Figure 3-1 Rational Equation: Q= ciA Gutter/Swale Flow, Time of Concentration: T,= L/60V Calculations By: M. Wohnrade Project: R/dgeview P.U.D. T0=Ti +T, Date: April 20, 2004 Upstream Owerland Flow Gutter Flow Swale Flow Time of Design Basins Concentration Area,A Runoff Point (acres) Coefficient Length,L Slope.S T, Length,L Slope,S Velocity,V T, Length,L Slope,S Velocity,V I T Intensity,i Flow,O T, c C, (ft) (%) (min) (ft) (%) (fps) (min) (ft) (%) (fps) (*,:,) ,,,, (inlhr) (cfs) 1 1 0.0 14.6 0.26 0.01 250 2.9 21.8 0.0 0.0 0.00 0.0 1446.0 1.61 2.58 9.3 31.1 4.35 16.5 2 2 0 0 86.2 0.21 0.01 400 3.6 25.8 0.0 0.0 0.00 0 0 909.0 2.60 328 4.6 302 4.42 80.0 3 3 0.0 4.0 026 0.01 361 4.0 23.6 0.0 0.0 0.00 0 0 0.0 0.00 0.00 0.0 23.6 5.11 5.3 S:IPROJECTSIPAF\Dfng\ChangeOfZone 20041Paf-DevQ.wpd Page 2 of 2 Wohnrade Civil Engineers,Inc. PATIO W W Z Z 7 7 LOT IMPERVIOUSNESS cc cc SINGLE FAMILY RESIDENTIAL (TYPICAL ALL LOTS) ROOF = 1 ,806 S.F. PATIO = 299 S.F. •''p}ipvEoOA". DRIVEWAY = 483 S.F. R.O.W. WALKS = 75 S.F. ': TOTAL = 2,663 S.F. = 0.06 ACRES GUTTER FLOWLINE CENTERLINE OF ROAD n. /Widen. Sy Doty "'°I•°�'PAF: 0301.00 ,-- N••t WOMAADE CIVL ENGINEERS, INC. P&A TURKEY FARM PUD 2695 W. EISENHOWER BLVD, LOVELAND, COLORADO 80538 SCALE:N.n. PHONE: 970-667-4995, FAX: 970-667-4984 gyp ''"mow 1 REaED ar:w+s TYPICAL IMPERVOIUS AREA / LOT 1 Drt�rsr+.n:ncnD °nE''''° D•/zs/ai Sa.ot. I k I I I i k L 4 III._ i I MI M I MIN I• I / / k / o> x n c r ."---)C / V'rrlK\o ----) m0 3 o - z u ,, _0 1 r m O I m LA r. —80 1 1 12 1 WIWI 1 i . illiiill iii -o � 0 i i J 1� II ii -ii I ifi lr WOHNRADE CIVIL ENGINEERS,INC. _ • RIDGEVIEW P.U.D. r it,$) Eln11 .. 11° = - HISTORIC CONDITION I:.�° DRAINAGE PLAN I I '''�ry°„nnmtma„•° NO. Revision*: By• Dote: l 1 k k .. [.__...v 11.,.E k ► i l k__ t i IL . fI__ _., IL _ < [_ x t ii1 I / / / // o c c r r nvniv vnn� 00 7 Li"n O Z lc.. m -o Q I m0,._, e >R , 8, . 11 ,,, . , ,,, . 1 i ! ! illiiiii _o 3 a J_. N ii I -r I l_p �'f#I!ir WOHNRADE CIVIL ENGINEERS,INC. =₹'c ",,,"""", RIDGEVIEW P.U D. 8 �` j«�d "° _ DEVELOPED CONDITION \ 'Nail' Pi."'(.b1•"-owe.r=0001•"-«« g' .�. � DRAINAGE PLAN BY: Dot.:f ' Drainage Design Considerations for ' P&A Turkey Farm PUD Sketch Plan Weld County, Colorado September 22, 2003 ' Prepared for: Sam Pluss/ P&A Turkey Farms, Inc. P.O. Box 22253 Denver, Colorado 80222 Prepared by: Wohnrade Civil Engineers, Inc. 2695 W. Eisenhower Boulevard, Suite 110 Loveland, Colorado 80538 Phone: (970)667-4995, Fax: (970)667-4984 I Project Number: 0301.00-PAF I d -- Wohnrade Civil Engineers, Inc. 2695 W. Eisenhower Blvd.; Suite 110 Loveland,Colorado 80538 Phone: 970-667-4995, Fax:970-667-4984 September 22, 2003 Weld County Department of Planning Services 1555 N. 17th Avenue Greeley, Colorado 80631 Re: Drainage Design Considerations for P&A Turkey Farm PUD Sketch Plan Weld County, Colorado Dear Staff: Wohnrade Civil Engineers, Inc. is pleased to submit this drainage study for P&A Turkey Farm for your review. This report complies with the storm drainage design and technical criteria defined in Section 24-7-130 of the Weld County Code. We acknowledge that review of this study by Weld County is for general conformance with submittal requirements, current design criteria and standard engineering principles and practices. If you should have any questions or comments as you review this report, please feel free to contact me at your convenience. Sincerely, WOHNRADE CIV ERS, INC. • -o: I®; 30325 / Mary B. Wohn P.E. O14.k. N • TABLE OF CONTENTS VICINITY MAP alli Page No. I INTRODUCTION 1.1 Objective 1 1.2 Project History and Previous Studies 1 1.3 Mapping and Surveying 1 II SITE LOCATION AND DESCRIPTION 2.1 Site Location 1 2.2 Site Description 1 III HISTORIC CONDITIONS 3.1 Historic Drainage Patterns 2 3.2 Historic Drainage Basins 2 IV DEVELOPED CONDITIONS 4.1 Proposed Site Development 3 4.2 Developed Drainage Basins 3 4.3 Developed Drainage Patterns 3 4.4 Detention Pond 1 4 V DESIGN CRITERIA 5.1 Design References 4 5.2 Hydrologic Criteria 4 5.3 Hydraulic Criteria 4 VI EROSION CONTROL 6.1 Erosion Control Plan 4 VII CONCLUSIONS 7.1 Compliance with Standards 5 7.2 Variances 5 REFERENCES 6 1 I I i EXHIBITS Exhibit 1 FIRM Title Box Exhibit 2 FIRM Map Panel 645 Exhibit 3 FIRM Map Panel 775 Exhibit 4 Off-site Basin Map Exhibit 5 Typical Section - Local Streets PLANS Sheet 1/2 Historic Condition Plan Sheet 2/2 Developed Condition Plan I APPENDICES Appendix A: Historic Condition Hydrology Appendix B: Developed Condition Hydrology I I I I I I I I ill9' VICINITY MAP P&A TURKEY FARM PUD 104°38'00"W 104°37'00"W 104°36'00"W WGS84 104°35'00" W ____-----e7 �� •' .�„ • `� L o figs• 23 23 4' 24 \ Z.-- C(-- o '•, c ` 71 MI l'.2°) 1 • 1 1 Auburn Sell. Fl,' ` .� 1. 'as '26 Jro 26 ] • . 25 / • n .30 •�/_ _ ,:v..........................,\'' I 464 '° ' — — U 9 Iliv. ..... *a 26 a 'MI o 0 777N' , r`o Auburn _ '� '`a, N C,JO6W ems eras .. _‘' WELD_ COUNTY ROAD 52� `a `. ' .74s :M66 •• \X679' 1, r (I., ' -, .. r ' ..443.491111r i � \\ _ a ...,„, 4. ..,.. p/ I )P&A TURKEY FARM PUD I• X4''... \ , �1 '5 I % ''. ,..r,..,__ 13 _ . /—",- ___ --_____ \, 4.4 ntb c-----(-------.1.1— Mil IInJY I � • .b, \c • --` cee t -: ,_.: WELD COUNTY ROAD 49 J) z z/', 78 •. 9 4785 - ,l--C-, OM 'ER i LATHAbf l''''- ' ,� � ..�: ref: -:-----":i.)'-\ \ )___H)... * -----\\ESERVOIR �, , _ .... . .., .:. ......oi I 7.- ..- .- Z ''- X. il 9 I "..\\\, • i — i I \ \---) 1--------s- , .. p 0669 ,4870 i• .• �� ,: 0 /'r---- • .....A .(� 1 I if (•-----",1----•'•-r ••• / N $ 1 • - f f c �. o 104°38'00"W 104°37'00"W 104°36'00"W WGS84 104°35'00"W vy TN}}}rfMN 0--- 3 tWtE I+l0° 0 I GOO FEET 0 500 t000 METERS �rf Map created with TOPOI®®2002 National Geographic(www.nationalgeographic.comftopo) ni Drainage Design Considerations for P&A Turkey Farm PUD Sketch Plan Weld County, Colorado September 22, 2003 INTRODUCTION 1.1 Objective This study documents the results of a comprehensive hydrologic and hydraulic analysis of both pre and post-development conditions for the proposed P&A Turkey Farm development. The proposed development is within a PUD Zone District in Weld County (County) and will be processed by the County thru the specific development guide submittal. 1.2 Project History and Previous Studies There are no know studies that precede this report. 1.3 Mapping and Surveying Field survey information and topographic mapping with a contour interval of 1- foot was obtained by Wohnrade Civil Engineers from King Surveyors, Windsor, Colorado. Additional topography outside of the project boundary was taken from USGS topographic mapping with a ten (10) foot contour interval. II SITE LOCATION AND DESCRIPTION 2.1 Site Location The site is located in the northeast quarter of Section 36, Township 6 North, Range 64 West of the 6th Principal Meridian, Weld County, Colorado. The site is bounded by Weld County Road 52 on the north and Weld County Road 49 on the east (See Vicinity Map.) 2.2 Site Description The P&A Turkey Farm site is approximately 126.2 acres and is currently in an Agricultural Zone District. The site is being used for agricultural purposes with a center pivot irrigating a portion of the site. Several oil field structures are located on the site with appurtenant access roads. The proposed area of development is located in the northeast corner of the site at the southwest corner of County Road 49 and County Road 52. The majority of the site will remain in dryland agricultural production. The Gilmore Ditch is located adjacent to the site on the west and flows from rr south to north. There are two ditch access roads located in the east and west sides of the ditch. There are two existing residences located to the north of the site along County Road 52 and one residence located east of the intersection of County Road 52 and County Road 49. Adjacent property directly east of the site is used for agricultural. Drainage Design Considerations Wohnrade Civil Engineers, Inc. P&A Turkey Farm PUD-Sketch Plan September 22, 2003 Page 2 There is an existing residence and outbuildings located on the east side of the site adjacent to County Road 49. County Road 49 is a paved arterial street and, County Road 52 to the north is a local road with a gravel surface. Soil borings located throughout the site have revealed groundwater at depths ranging from four (4) feet to eight (8) feet below existing grade(See soils report.) Surface soils consist of silty sand and sandy lean clay. The Flood Insurance Rate Maps (FIRM's) from the National Flood Insurance Program have been referenced to determine if the site is located within a regulatory floodplain. FIRM map panels 645 and 775 dated September 28, 1982 verify that the site lies outside of the regulatory floodplain (See Exhibits 1 thru 3.) III. HISTORIC CONDITIONS 3.1 Historic Drainage Patterns The majority of the site (100.6 acres) drains overland from east to west at slopes ranging from 0.76% to 4.55% towards the Gilmore Ditch. Stormwater runoff from a small portion of the site (4.0 acre) drains to the a northeast to the intersection of County Roads 49 and 52. Stormwater runoff that reaches this intersection is conveyed over the road and continues to the north. There was no visible evidence of a culvert at this location. There is no stormwater runoff entering the site from offsite basins (see Exhibit 4). 3.2 Historic Drainage Basins The site is has been divided into three historic drainage basins. Two of the basins drain toward the Gilmore Ditch. The third basin drains to the intersection of County Road 49 and County Road 52. Basin H1 (15.6 acres) drains overland from east to west towards the Gilmore Ditch. The 5 and 100-year peak discharges from Basin H1 are 0.3 cfs and 13.2 cfs respectively. The majority of the development will take place within this basin. Basin H2 (85.2 acres) drains overland generally from east to west towards the Gilmore Ditch. The 5 and 100-year peak discharges from Basin H2 are 3.9 cfs and 79.1 cfs respectively. The majority of this basin will remain undisturbed. Basin H3 (4.0 acres) drains overland to the northeast corner of the site to the intersection of County Road 49 and County Road 52. The 5 and 100-year peak discharges from Basin H3 are 1.0 cfs and 5.5 cfs respectively. 0 0 Drainage Design Considerations Wohnrade Civil Engineers, Inc. P&A Turkey Farm PUD-Sketch Plan September 22, 2003 Page 3 VI. DEVELOPED CONDITIONS 4.1 Proposed Site Development The proposed development of the site will consist of 9 single-family estate lots, two outlots of 101.106-acres to be dedicated as Conservation Easements, and 6.535 acres of open space. Site improvements will include a cul-de-sac road, Ridgeview Lane, with roadside ditches and a potable water distribution system. It is questionable whether or not County Road 52 will be paved from Ridgeview Lane to County Road 49. There is also the potential for the site to be served by a dual water system for both domestic potable usage and, raw water for irrigation purposes. It is anticipated that homes built in the P&A Turkey Farm development will have full basements. Due to groundwater encountered on the site, each lot will be evaluated to ensure that the bottom of the foundation footer is a minimum of three (3) feet above the groundwater elevations measured on February 25, 2000. 4.2 Developed Drainage Basins The site has been divided into three (3) developed basins. Runoff from roughly 14.6 acres of the PM Turkey Farm site will be routed to an on-site detention pond (Pond 1) located in the northwest corner of the site, adjacent to the Gilmore Ditch (See Sheet 2/2.) Developed runoff from the 100- year storm will be released at a 5-year historic rate into the Gilmore Ditch. 4.3 Developed Drainage Patterns The overall drainage pattern of the site will remain unchanged from pre to post- ] development conditions. Basin 1 (14.6 acres) will drain overland and in roadside ditches to Detention Pond 1. The peak 5- and 100-year discharges at Design Point 1 are 2.6 and 16.5 cfs respectively. Basin 2 (86.2 acres) will continue to drain overland towards the Gilmore Ditch. The peak 5- and 100-year discharges at Design Point 2 are 4.0 and 80.0 cfs respectively. Basin 3 (4.0 acres) will drain overland to the northeast corner of the site to the intersection of County Road 49 and County Road 52. The peak 5- and 100-year discharges at Design Point 3 are 0.8 and 5.3 cfs respectively. J a a 0 Drainage Design Considerations Wohnrade Civil Engineers, Inc. NA Turkey Farm PUD-Sketch Plan September 22,2003 Page 4 4.4 Detention Pond 1 Detention Pond 1 is located in the northwest corner of the site adjacent to the Gilmore Ditch. This pond will serve as a detention facility for the developed JI portion of the P&A Turkey Farm site. The 100-year peak discharge from the developed site will be released at a historic 5-year rate thru a proposed circular orifice. Released stormwater will then follow the historic flowpath to the Gilmore Ditch. ] V. DESIGN CRITERIA 5.1 Design References J Drainage criteria outlined in the Storm Drainage Criteria Manual by the Urban Drainage and Flood Control District (Reference 1), has been referenced in the preparation of this study. 5.2 Hydrologic Criteria Due to the relatively small basin size the Rational Method has been used to estimate peak stormwater runoff from the project site. Calculations made as part of this investigation along with other supporting material, are contained in Appendix A. An initial 5-year design storm and, major 100-year design storm have been used to evaluate the proposed drainage system. Rainfall intensity data for the Rational Method has been taken from IDF equations generated specifically for the P&A Turkey Farm site by the computer program "Watershed Modeling" by Eagle Point software. Input of precipitation amounts for the generation of intensity equations have been taken from the NOAA Atlas 2, Volume III- Colorado. 5.3 Hydraulic Criteria Where applicable, the following computer models have been utilized: • The computer program "Flowmaster" has been used to analyze the capacity a of proposed swales; • The computer model "HY8" by the U.S. Department of Transportation, Federal Highway Administration has been used to analyze proposed culverts. U VI. EROSION CONTROL 6.1 Erosion Control Plan The proposed rainfall erosion control plan during construction will consist of temporary structural erosion control measures. Silt fencing will be installed along the top of bank on the east side of the Gilmore Ditch to prevent sediment migration. Permanent vegetative erosion control will be used in conjunction with landscaping surrounding future residences. Permanent revegetation of areas a Drainage Design Considerations Wohnrade Civil Engineers, Inc. P&A Turkey Farm PUD-Sketch Plan September 22,2003 Page 5 disturbed by construction will be the responsibility of the contractor. Permanent riprap will also be provided at the outlet of Pond 1. VII. CONCLUSIONS 7.1 Compliance with Standards All applicable drainage criteria have been complied with in accordance with the "Weld County Code". The proposed drainage improvements do not adversely impact surrounding properties. This study conforms to the guidelines specified in Section 27-6-50, paragraph B, item 7, of the Weld County Code. 7.2 Variances No variances are requested as part of this development. 0 U 0 U U 0 0 a 0 U 0 Drainage Design Considerations Wohnrade Civil Engineers, Inc. P&A Turkey Farm PUD-Sketch Plan September 22, 2003 Page 6 J REFERENCES 1) Urban Storm Drainage Criteria Manual, Urban Drainage and Flood Control District, Wright McLaughlin Engineers, Denver, Colorado, March, 1969. D O U U U 0 U O a a a 1 l l Exhibits Li i NATIONAL FLOOD INSURANCE PROGRAM NATIONAL FLOOD INSURANCE PROGRAM JJ fr FIRM FIRM FLOOD INSURANCE RATE MAP FLOOD INSURANCE RATE MAP V P,' WELD WELD COUNTY, COUNTY, COLORADO COLORADO UNINCORPORATED AREA UNINCORPORATED AREA PANEL 645 OF 1075 PANEL 775 OF 1075 a (SEE MAP INDEX FOR PANELS NOT PRINTED) (SEE MAP INDEX FOR PANELS NOT PRINTED) }y I l@ mj i 8 F( COMMUNITY-PANEL NUMBER COMMUNITY PANEL NUMBER ! 080266 0645 C 080266 0775 C MAP REVISED: _ MAP REVISED: SEPTEMBER 28, 1982 ,# SEPTEMBER 28, 1982 { i federal emergency management agency 1 federal emergency management agency T M 40301.00 P&A TURKEY FARM mee: WOHNRADE CIVIL ENGINEERS, INC. 1 69/44/O, Sheet 'Seale: EXHIBIT 1 ela a.��o do r6 Suite 110 ,.;II }1A. Phone: (970)667-4995.Far(970)667-4984 �c$ Designed ey. FIRM TITLE BOX "' 5 J I „Sheetsl O1 ,. + -.Y.,r;r. ^. 4 -.+:.e..'�-°-' +r^+t�v.�.ar:: 'S.+,• r ,"-t tS.1 ' '-•+q Hit' 9fi�..-s,aee -xw.s.^:. , a L a, q a5x�5 e'�.t b, ,x .y; of:_ g �"`,. , r�§'� 4 •?" 1 IL • i', .n J _— n _ .:..r+wum..ofy.+.� _ - _,...,„„4.A,- - W,.r,,31 , A c 19 ‘\.\:\ \NS") 25 Q /d J \li �. %“, Gff'\`\ I /1 Si 11' l ' 36 ,' _—,�':DI 31 6 t(�`` J \‘' P&A TURKEY LC) Ct. C C l ‘ N."\ FARM PUD p( 1 ( REFERENCE' FLOOD INSURANCE RATE MAP, WELD COUNTY CO CO COLORADO, PANEL 845 OF 1075, MAP REVISED SEPTEMBER 28, 1982. /// • P&A TURKEY FARM Pte. 0301.00 WOHNRADE CIVIL ENGINEERS, INC. 2 Date. Sheet 69/1]/0.3 le: EXHIBIT 2 lmela W. Co,arado.r86�Suite 110 A Phone: (970)667-4995, For (970)667-4984 5, Designed By: FIRM MAP PANEL 6455 aw ‘,Sheety LI( \ T T LJ \\:::‘,. i \� r x.a 35 /------- II �- 11 36� :/ A k 4 P&A TURKEY • 1\\ FARM PUD \ \\\ . , a 4. \� ' N 1,---_..c.J......_ ., (l . •-\ \ // II: t........ REFERENCE, FLOOD INSURANCE RATE MAP, WELD COUNTY COLORADO, PANEL 775 OF 1075, MAP REVISED SEPTEMBER 28, 1882. /// PKU0001.00 , P&A TURKEY FARM -**\WONNRADE CIVIL ENGINEERS, INC. 3 09/22/03 Sheet 2695 W. Eisenhower 6tW., Some 110 t EXHIBIT 3 weed. Colorado. 60536 NA signed By: rPhone: (970)667-4995, Fat (970)667-4964 5 \ l FIRM MAP PANEL 775 $haste W -, r/ It (nw .r°®° t• — i )S °i r � . . N.‘-----..„. : , ,- - - -.AN: ‘r i . 4 71/ l {:a . , th epia.r...---4els-12%*".",...we' g .1 \ \en." ee ( i .� \�. Nom@ t ! (Li -. , }) i( _ i p - ;F4 I 17 4 Ftti jI Le1I .., l' s INS\� t t 1 . • II 4 ` 3 .L I' ra s.t.. III Pm)`d:'°!°° P&A TURKEY FARM PAF: ° WOHNRADE CIVIL ENGINEERS, INC. 4 Date: - Sheet 09/23/03 EXHIBIT 4 2695 W. Esenhower 8 . Sue 110 el Seale: Loveland, Colorado.Eo.o. M 80839 rns Phone: (9)!1)06]—{995. Fox (9]0)66]-4984 � Designed By: OFF-SITE BASINS „Sheets./ o Li R.O.W. R.O.W. 60'-0" 30'-0" E.O.P. E.O.P. In I 24'-0" I E SHOULDER SHOULDER -8'-0" '-0'' 12'-0" 12'-0" -6'-0" '-0 �4:1 MA �� 2% MIN. 2 MI%gyp! � X T(?' ,. > SWALES AS REQUIRED BMJMINOUS ASPHALT PAVEMENT (THICKNESS TO BE DETERMINED IN FINAL DESIGN) GRAVEL SHOULDER (SPECIFlCAHONS TO BE DETERMINED IN FINAL DESIGN) GRAVEL BASE COARSE OR FULL DEPTH ASPHALT (THICKNESS TO BE DETERMINED IN FINAL DESIGN) NOTE: PAVEMENT SECTION TO BE DESIGNED BY SOILS ENGINEER AND APPROVED BY COUNTY ENGINEER PRIOR TO CONSTRUCTION TYPICAL SECTION - LOCAL ROADWAY 24' PAVEMENT W/ 4' SHOULDERS NOT TO SCALE °"`� P&A TURKEY FARM PpF: 0301.00 NA Designed By: la Oats WOHNRADE CIVIL ENGINEERS, INC. 269a9Az2�ai Sheet EXHIBIT 5 W W. Colorado, 80538 W e 110 Scale: Phone:(970)667-4995. Far (970)667-4984 x5 TYPICAL STREET SECTION �" I.._ \sheets/ 1 1 Appendix A S /. ifx:+' 3^$' i2 �+ ,._+d• } ,. 1 $ i r Y4s rz`xt.§+° +zy; *tv r+ m' x a3 d"' r t-g a s, r tS, "°:.'ate-'e 'AT tone ! r fcgn - s +Ea '. �"-43 vt ilt it . cnpos,ite;Rui of`�(3oeff1 on Ca *64 "Ia !$iis: , ,..1,.e,. t ass, 4n - . 7 m,V''''o� t' Vic. <r-t✓1?^.,. ,1,° , r `R₹'�'2va3n nr„ rc, '�',.ei a,l. .6, z;..w" Z;,Si. Character of Surface Runoff Project: P&A Turkey Farm Coefficient Calculations By:M.Wohnrade Streets:Paved 0.88 Date:September 17,2003 Streets:Gravel 0.45 J Drives and Walks 0.87 Roofs 0.85 Undeveloped Areas 0.01 Runoff Coefficients are taken from the Town of Windsor Storm Drainage Design Criteria Manual,Table 3-1 I Basin Basin Area of Area of Area of Area of Roofs Area of Weighted ID Area Streets: Streets: Concrete Undeveloped Runoff Paved Gravel Lawns,Sandy Soil Coefficient (Acres) (Acres) (Acres) (Acres) (Acres) (Acres) LJ H1 15.6 0.00 0.00 0.00 0.00 15.60 0.01 r H2 85.2 0.94 0.00 0.00 0.00 84.26 0.02 H3 4.0 0.30 0.00 0.02 0.06 3.62 0.09 !-- u 3�' c r'w s r ,`+.L '' x s „'�'-.i-«�p^y v 0-` z""2a re ®�'j. ¢ h✓' ji"^` p r .+�,'3 '✓^-d t r ; - a..r ,;..� z+' - :�c v `VANec s or c-Condition - 7uuei eaPs`.`sta, w�v a4'' ^ E`b ; �� C to osrtef t no t doIfscie`n Cale atia1KtIts Character of Surface Runoff Project: P&A Turkey Farm Coefficient Calculations By:M.Wohnrade Streets:Paved 0.93 Date:September 17,2003 Streets:Gravel 0.60 Drives and Walks 0.89 --- Roofs - 0.90 _. Undeveloped Areas 0.20 Runoff Coefficients are taken from the Town of Windsor Storm Drainage Design Criteria Manual,Table 3-1 L-3 Basin Basin Area of Area of Area of Area of Roofs Area of Weighted ID Area Streets: Streets: Concrete Undeveloped Runoff Paved Gravel Lawns,Sandy Soil Coefficient — (Acres) (Acres) (Acres) (Acres) (Acres) (Acres) — H1 15.6 0.00 0.00 0.00 0.00 15.60 0.20 ,- H2 85.2 0.94 0.00 0.00 0.00 84.26 0.21 H3 4:0 0.30 0.00 0.02 0.06 3.62 0.27 S:tPROJECTSWAFIHydrologylPaf-HistC.wpd Wohnrade Civil Engineers, Inc. K I 0 1 L 1 L (+ k I i L i L 1 I L J L fi L 1 C 6 1 1 i Historic Condition: 5-yr Runoff Computations Weld County, Colorado, Intensity, (i)taken from intensity formula Overland Flow. Time of Concentration: for P&A Turkey Farm, i=40.20/(Te+9.12)°.7° T= 1.8(1.1-05)L1a/S13 Velocity, (V)taken from Figure 3-1 • Rational Equation: Q=ciA Gutter/Swale Flow.Time of Concentration: T1= L/60V Calculations By: M. Wohnrade Proiect: P&A Turkey Farm TO T1+Tt Date: September 17, 2003 ah P 1. `( *rvt roe' rne'7i { w 1• Y P v' +, a y �, b > F h !, 5 4a1 (_, Upstream i �H �, 6verland,out " -5?( r^ ,r r 'U S'0e°erFlow t r 4!: *x SweIePlGw a a° f Time of It v,re,R"t + 4 ^. x 2 bit �� 'M..U { *, sr�" , b sr • 4 �a z ,, �k:. t `.: C ,'xt"ru.,..," ,,., ,:$k. ,,-".-^y..k:'�a t.u.1 „ rte .'i�'a „P.S°k .vaJ. hs'C u.,rc. }, rs.ai P.a .F" v'�. �', a: Design Basins Concentration Aree,A Runoff x" Point (acres) Coeffident Length,L Slope,S T, Length,L Slopes Velocity,V T, Length,L Slope,S Velocity,V r T, Intensity,i FIow,0 .�,,,aa T. c C5 (ft) (%) (min) (ft) (%) (fps) (min) (ft) (%) (fps) t aw (inmr) Cots) }C S Safe 154.94144140 m°A�t 44ftti` ;+✓$K"h, M(. H1 H1 .xre 15.6 0.01 0.01 400 23 :$9:Z? 0.0 0.0 0.00 j{Qf}, 651.0 3.60 3.86 Ott 32.5 2.19 0.3 H2 112 4°9.51^ M( 65.2 0.02 0.01 400 3.6 25'6 0.0 0.0 0.00 NIN 909.0 2.60 3.26 gwra 302 2.29 3.9 113 H3 ititt^ill 4.0 0.09 0.01 3°1 4.0 k 66 '. 0.0 0.0 0.00 „§' 0?(' 0.0 0.00 0.00 '"n`bsa` 23.6 2.65 1.0 S:IPROJECTS'PAFHydrologywaf•HistO.wpd Page 1 of 2 Wohnrade Civil Engineers,Inc. 1_ i 1 rn 0 6 1 6. 1 6 h 1 6 6 1 6 1 6 1 i 1 1 C 11 1 6 Historic Condition: 100-yr Runoff Computations Weld County, Colorado, Intensity, (i)taken from intensity formula Overland Flow, Time of Concentration: for P&A Turkey Farm, i=77.541(T0+9.12)°.7° TI= 1.8(1.1-05)L112/S113 Velocity, N)taken from Figure 3-1 Rational Equation: Q= ciA Gutter/Swale Flow, Time of Concentration: Ti L/60V Calculations By: M. Wohnrade Proiect: NA Turkey Farm Tc=Ti+T, Date: September 17, 2003 A'ik ifs 4r 't 5 e nd at S INI ti ON) 43 r 5 , 4att i y a" r ?... Upstream t s+. x r�a CvatlandFlaw 3 ?. A ti yM etertI 0W /A r'y SSwelnF r a ,''. Time of (h.silit?...rc:2__. '�`��k'.`7 .� ::tr r',„` zzst.J .'^ F Yr4at..{�S'..va;� '^*,, ,.; ✓ _gat,-F.,<ttvr. .,kg �^:arrt4>isu,'`�=1�. Design Basins Concentration Area,A Runoff Point (acres) Coefficient Length,L Slope,S T, Length,L Slope,S Velocty,V T, Length,L Slope,S Velocity,V T T Intensity,l Flow,O T, a Cs (8) (%) (min) (n) (%) (fps) (mk.) (ft) (%) (fps) 0'4 (Whr) (cis) HI Hi $'gam, r Cn - ' "YtO 75.6 0.20 0.07 400 2.3 ,'w 0.0 0.0 0.00 41'40( 651.0 3.60 3.66 iA 32.5 423 . 13.2 Le ✓5v P1�,.+s ru strY+ ,,, H2 H2 H '° 00 „,„ 65.2 0.21 0.01 400 36 f''25.B` ' 0.0 0.0 0.00 1,60` 909.0 2.60 3.26 48-' 30.2 4.42 70.1 A tY H3 H3 ai?'�P i�0. 4.0 0.27 _0.01 361 40 Vflagni 0.0 0.0 0.00 WdO 0.0 0.00 0.00 nne 23.8 5.11 5.5 SAPROJECTSIPAF\HydrologpPaf-HIstQ.wpd Page 2 of 2 Wohnrade Civil Engineers,Inc. Table 3-1 RECOMMENDED RUNOFF COEFFICIENTS AND PERCENT IMPERVIOUS Runoff Coefficients Storm Frequency Land Use or Percent Surface Characteristics Impervious 2 5 10 100 Business: Commercial Areas 95 .87 .87 .88 .89 Neighborhood Areas 70 .60 .65 .70 .80 Residential: Single-Family .40 .45 .50 .60 Multi-Unit(detached) 50 .45 .50 .60 .70 Multi-Unit(attached) 70 .60 .65 .70 .80 'A Acre Lots or Larger .30 .35 .40 .60 Apartments 70 .65 .70 .70 .80 Industrial: Light Areas 80 .71 .72 .76 .82 Heavy Areas 90 .80 .80 .85 .90 Parks. Cemeteries: 7 .10 .18 .25 .45 Playgrounds: 13 .15 .20 .30 .50 Schools: 50 .45 .50 .60 .70 Railroad Yard Areas: 20 .20 .25 .35 .45 Undevelooed Areas: Historic Flow Analysis, 2 (See Lawns) r Greenbelts, Agriculture, Offsite Flow Analysis 45 .43 .47 .55 .65 (When land use not defined) Streets: Paved 100 .87 .88 .90 .93 Gravel (Packed) 40 .40 .45 .50 .60 Drives and Walks: 96 .87 .87 .88 .89 Roofs: 90 .80 .85 .90 .90 Lawns, Sandy Soil 0 .00 .01 .05 .20 LlLawns, Clayey Soil 0 .05 .15 .25 .50 * See Figure 2-1 for percent im pervious. 11-1-90 / URBAN DRAINAGE AND FLOOD CONTROL DISTRICT / °` ,o3 TABLE 3-1 /, A 0301.00 Date: WOHNRADE CIVIL ENGINEERS, INC. 09��Q, Sheet 2695 W Eaenbe.er Blvd., Suite „0 °° RATIONAL METHOD °(g]p)56]a{g95F°x (9]0)66] 4984 Designed l RUNOFF COEFFICIENTS ‘Sh1 tee LJ C] OUser Name: Mary Date: 06-08-02 Project: P&A Turkey Farm Time: 07:19:06 D Network: 00 - Page:. 1 Rainfall Report Li Rainfall Type Western Rainfall Library P&A Turkey Farm CJ Western Precipitation 0 2yr/6hr 1.40 in 2yr/24hr 1.70 in 100yr/6hr 3.40 in U 100yr/24hr 3.80 in Elevation 4767.00 URainfall Intensity (in/hr) 5 min 15 min 30 min 60 min 6 hr 24 hr U 2 yr 3.60 2.36 1.64 1.04 0.23 0.07 5 yr 5.14 3.37 2.34 1.48 0.31 0.09 10 yr 6.17 4.04 2.80 1.77 0.37 0.11 Li 25 yr 7.51 4.92 3.41 2.16 0.44 0.12 50 yr 8.74 5.73 3.97 2.51 0.50 0.14 100 yr 9.92 6.50 4.50 2.85 0.57 0.16 UBDE Values Intensity = B/(Tc + D)AE B D E X Y 0 2 yr 28.16 9.12 0.78 0.00 0.00 5 yr 40.20 9.12 0.78 0.00 0.00 10 yr 48.23 9.12 0.78 0.00 0.00 25 yr 58.67 9.12 0.78 0.00 0.00 CJ 50 yr 68.30 9.12 0.78 0.00 0.00 100 yr 77.54 9.12 0.78 0.00 0.00 0 0 0 a 0 U L ---- .50 2. .20 .10 m O. 0 °1 .06 m m I. u 1m .04 .02 .01 • .00s 1 2 4 6 10 20 Average velocity(ft/sec) EQUATION FOR FIGURE 3-1: PAVED: V=16.1345(s)(3•5 (210VI-78-66,Second Ed.,June 1986) UNPAVED: V=20.3282(s)°'5 s= slope in ft/ft °`t A FIGURE 3-1 / 09111.00 Date: WOHNRADE CIVIL ENGINEERS, INC. 1 ��°� AVERAGE VELOCITIES Sheet 8695 nW.d E°°Mo.°r 0538 Stub 110 311 °° FOR SHALLOW °(970)667-4995 Fax (970)667-4964 Designed By: CONCENTRATED FLOW `� 1 �sh J Appendix B w -04%i � . 'mc 5^ bb b •e2y �+{ k \ k 3`4i b T +i a¢`uy tit-h. ,k t�+ 'a �i elE L, , �" p a Y.₹ t� -'4^i,C i P�t�w „ 7, 1 - X7;4#elo ed do !krreartA �� t 5 '� Tj% c .?,-.?-,ei e` fl `i P `r fv-ehi t""aw ,Ht` ,' "' in t, iy. -..4* Eo o 3' :. ' ,' irrapos,tel unoff oefi t a., Catculatto, 3` 4 44rt Character of Surface Runoff Pmject: PM Turkey Farm Coefficient J Calculations By:M.Wohnrade _ Streets:Paved 0.88 Date:September 18,2003 Streets:Gravel 0.45 Drives and Walks 0.87 r Roofs 0.85 L Undeveloped Areas 0.01 Runoff Coefficients are taken from the Town of Windsor Storm Drainage Design Criteria Manual,Table 3-1 Basin Basin Area of Area of Area of Area of Roofs Area of Weighted ID Area Streets: Streets: Concrete Undeveloped Runoff Paved Gravel Lawns,Sandy Soil Coefficient (Acres) (Acres) (Acres) (Acres) (Acres) (Acres) 1 14.6 0.53 0.55 0.00 0.31 13.21 0.08 2 86.2 0.94 0.00 0.00 0.04 85.22 0.02 3 4.0 0.30 0.00 0.02 0.02 3.66 0.08 r s 4 T vb'" - h`� ie - 5 ^'3 4 6j .1Y� 4-'-€7.y — ''-'4M: �w ti ,.v- ' frei�' #.s , :a`r-j m'4'"`'. £bra ', v rs 4 �o ..` DeveIo eatCondition - 100 Year��` '� _` `,y +R+"/��y/yy[y+]z��w?I'`��{S',�-"`*.55'?se e •rp ,>; nY.� a� A"'3 R� �'.k.`�Nz, m 4*� �.. e., �v ,,, ei� ritl /_ `kite- po effidfe� Ql lat oo fly1Si � . 'S r,rs ,�.5an 4' rt. ,And O, .-,'F 1 Max..a rs s.va mtY.a:"i*X M . -k < . . T Character of Surface Runoff Project:: PM Turkey Farm Coefficient Calculations Br M.Wohnrade Streets:Paved 0.93 Date:September 18,2003 Streets:Gravel 0.60 Drives and Walks 0:89 Roofs 0.90 Undeveloped Areas 0.20 Runoff Coefficients are taken from the Town of Windsor Storm Drainage Design Criteria Manual,Table 3-1 s Basin Basin Area of Area of Area of Area of Roofs Area of Weighted ID Area Streets: Streets: Concrete Undeveloped Runoff Paved Gravel Lawns,Sandy Soil Coefficient (Acres) (Acres) (Acres) (Acres) (Acres) (Acres) 1 14.6 0.53 0.55 0.00 0.31 13.21 0.26 2 86.2 0.94 0.00 0.00 0.04 85.22 0.21 3 4.0 0.30 0.00 0.02 0.02 3.66 0.26 S:tPROJECTSIPAF\Dmg\Paf-DevC.wpd Wohnrade Civil Engineers,Inc. r1 n IC ® C C C 0 C t ® Q C ® CI IC © C3 Developed Condition: 100-yr Runoff Computations Weld County, Colorado, Intensity, (i)taken from intensity formula Overland Flow, Time of Concentration: for P&A Turkey Farm, i =77.541(T0+9.12)amfi TI= 1.8(1.1-05)L72/S1" • Velocity, (V)taken from Figure 3-1 Rational Equation: Q=ciA Gutter/Swale Flow.Time of Concentration: Tt= L/60V Calculations By: M. Wohnrade Proiect: P&A Turkey Farm T0=TI+TI • Date: September 18, 2003 r t n ht jn 4,yr JT} '� lqf q ) M `e, S ,c a •:..4.0.4,,i,::„1.,."� �. , Upstream r ;; S�s x Ove/Iendflwaw m r M1 aa et:� fr,3, V v ,Queer FYow a� �. uSven 6Flew a{ 44 r lime of Y,.xff4f,. `;"r ','<§,1. .`_.e 5 ,.,�'Any °J ,.W�31atfvr Igi'l. _v'�`;-s f_ �i^ k w� ..,S .,, t. _^ .46x-',A +. l2WArz Design Basins Concentration Area,A Runoff - -Point (acres) Coefficient Length,L Slope,S T, Length,L Slope,S Velooily,V T, Length,L Slope,S Velocity,V T T, Intenslty,l FIow,Q 7, c C, (e) (%) (min) (8) (%) (fps) (min) (e) (%) (fps) N' a+u (inlhr) (afs) y 7 1m„��' 146 A.ZB 0.01 250 29 "">. �SS SASS: 0.0 0.0 0.00 �' 74480(1W .0 1.81 2.58 fa 31.1 435 18.5 s>? .c 2 2 trail ea2 0.21 0.01 400 38 8�r,^,r 0.0 0.0 atm a a 909.0 2.80 128 if 30.2 442 80.0 3 3 M `a'q0 '1"41 4.0 0.28 0.01 381 4.0 ` 423t844F 0.0 0.0 0.00 p Ida; 0.0 0.00 0.00 w'"s,0Q"d: 23.8 5.11 5.3 • S:IPROJECTSIPAF(DmglPat-DevQ.wpd Page 2 of 2 Wohnrade Civil Engineers,Inc. I -I n r n o CD o o CI Cl o Cl o o © © o CI Developed Condition: 5-yr Runoff Computations Weld County, Colorado, Intensity, (i)taken from intensity formula Overland Flow, Time of Concentration: for PM Turkey Farm, i=40.20/(Te+9.12)°'8 TI= 1.8(1.1-05)L112/S1f' . Velocity, (V)taken from Figure 3-1 Rational Equation: Q=ciA Gutter/Swale Flow, Time of Concentration: T1= L/60V • Calculations By: M. Wohnrade Project: PICA Turkey Farm Tc=Ti+Ti Date: September 18, 2003 _'+ 5 »rvrv'd n6 !'•t re u t 4 x " v k r to 1 r- Upstream s 3t�r �'` ovetlend FIoW' + µSs 1 4I vP r w L ti GSdetF1ow °1,Y k` i FA(k { n 'eI:rsr ext s. ,4 -;* Timed ..{.w ' " �.1 z +` 9, P i r ,4P c 4 v,, x r`J.'&J`„`.- G .vl x '"h `�.z.,A ; . e #i ,,,,z., rti , ,•.�n _ _.. 1... . y Teo iw r-wM.t. .C+ �re....2 ,fi a. ,vd w3 n 21 r$ Design Basins Concentration Area,A Runoff Point Polnl (acres) Coefficient Le(i) SI(%) T, Le(i) Sl(%) Ve(ms) T, Left) SI(%) Ve(fps) T T Intensity,) Flow) T, c Cs (ft) (%) (min) (ft) (%) (fps) (min) 90 OA) pps) a+u os„ . OW We) a 1 1 , marl 146 0.08 0.01 250 29 Pl114 0.0 CO 0.00 %IS 1446.0 1.61 2.58 wok31.1 226 2.6 2 2 tra, . a 3a 2a Sa ' „e ,,, r. ,� " �b 88.2 0.02 0.01 400 36 1:. 256 . 0.0 0.0 0.00 AQ4 909.0 Z60 3.28 " 302 2.29 4.0 3 3 eti00,e 4.0 0.08 0.01 381 4.0 R 2'6 '+3 0.0 00 0.00 g-"AL, 0.0 0.00 0.00 'Y�`,M 23.8 2.65 0.8 S:(PROJECTSIPAF\Dmg\Paf-Devo.wpd Page 1 of 2 Wohnrade Civil Engineers, Inc. n n n n 1p c If= Io CI CI ID Cl CD CI II) Io O ci PATIO u, v, • LOT IMPERVIOUSNESS SINGLE FAMILY RESIDENTIAL (TYPICAL ALL LOTS) ROOF = 1 ,806 S.F. PATIO = 299 S.F. °�T1vrwAx DRIVEWAY = 483 S.F. WALKS = 75 S.F. TOTAL = 2,663 S.F. = 0.06 ACRES GUTTER FLOWLINE CENTERLINE OF ROAD • Rolkm er n°I"�`PAF: 0301.00 N' Shell f WOFNiADE CIVL9, NC. �A P&A TURKEY FARM PUD 1 Il 2895 W. EISNE: 9700E5 BLVD, ,LOVELAND, COLORADO 60538 �,,o,,,,�W laws=a,:u� - TYPICAL IMPERVON9 AREA / LOT J / 1 PHONE 970-887 BLVD, FAX: 970-88ORADO w4sra,x:•c•o rv,yuan:m/�N+ ` ` ynu,. i f S Plans C7 C C7 C=3 IC IC IC C C7 C C IC] C IC CJ ID C IC • • / / r • i iI / I / �i/ / - — ~`\ J • f , j per. • ,n pc, z IIm _o I I ' r � r CO IM III O`0 1 1 I. J P r l .J� I � 0 l i- i I 1 CD If Fr r 3{ l 8 9 eMY14/ 1 / O r iirifip WOHNRADE CIVIL ENGINEERS, s°'.,U: . • PIA TURKEY FARM ITO !I igro,uiI„e1, ,I,,,,,.,,,,.,,4 ne�a , m % .• HISTORIC CONDITION 0$ DRAINAGE PLAN No. ReNalonx By: Date! r ci ci IF-1 ci IC CI ED IC IC C © ci CI ci ci IC i- -I C Irl / I / N. • /` / r / 1 __ �_ i _ S r. v,im n V(n T Z cnWD rr o II CA m ya r l m n v D g� I ®Z r.�, I, ! W • ii q I iv 0 \ gg pgl If i1Y WONNRADECML ENGINtrm ../ ")b,4,INC: uk ,• FAA TURKEY FARM _ _ 11`-, YYYYY��« PSI PS`s") "e'f� � �,,%_. DEVELOPED CONDITION ,,;,��r. DRAINAGE PLAN GEOTECHNICAL ENGINEERING REPORT � PROPOSED RESIDENTIAL SUBDIVISION WELD COUNTY ROADS 49 AND 52 IMF KERSEY, COLORADO TERRACON PROJECT NO. 21005009 May 17, 2000 Id pl! lierracon 0 0 GEOTECHNICAL ENGINEERING REPORT PROPOSED RESIDENTIAL SUBDIVISION WELD COUNTY ROADS 49 AND 52 KERSEY, COLORADO TERRACON PROJECT NO. 21005009 May 17, 2000 U o Prepared for: P & A Turkey Farms PO Box 22253 Denver, Colorado 80222 Attn: Mr. Sam Pluss Prepared by: Terracon 1289 First Avenue Greeley, Colorado 80631 U W lierracon 0 : { lierracon May 17, 2000 1289 First Avenue y P.O.Box 1744 Greeley,Colorado 80632-1744 (970)351-0460 Fax:(970)353-8639 P &A Turkey Farms PO Box 22253 Denver, Colorado 80222 Attn: Mr. Sam Pluss Re: Geotechnical Engineering Report Weld County Roads 49 and 52 Terracon Project No. 21005009 Terracon has completed a geotechnical engineering exploration for the proposed subdivision to be located near the intersection of Weld County Roads 49 and 52 near Kersey, Colorado. This study Q was performed in general accordance with our proposal number 2199p147 dated December 17, 1999. The results of our engineering study, including the boring location diagram, laboratory test results, test boring records, and the geotechnical recommendations needed to aid in the design and construction of foundations and other earth connected phases of this project are attached. The subsurface soils at the site consisted of silty sand and sandy lean clay. The soils are underlain at depths of 21/2 to 13/ feet by sandstone/claystone bedrock. The results of our field exploration and laboratory testing indicate that the soils have non to low expansive potential and the bedrock has moderate to high expansive potential. The soils and bedrock at anticipated foundation bearing depth have low to high load bearing capability. Based on the geotechnical engineering analyses, subsurface exploration and laboratory test results, we recommend that proposed structures placed a minimum of three feet above the claystone bedrock be supported on a spread footing foundation system. If foundations are placed in or within three feet of the claystone bedrock a graded beam and drilled pier foundation system should be used for support of the structures. T Slab on grade may be utilized for the interior floor systems when the subgrade consists of on-site soils and is placed four feet above the bedrock. Given the engineering characteristics of the claystone bedrock that may support slabs, consideration should be given to the use of structural 410 floor systems. Other design and construction recommendations, based upon geotechnical conditions, are presented in the report. Arizona■Arkansas•Colorado•Georgia a Idaho t7 Illinois Iowa■Kansas 01 Kentucky■Minnesota■Missouri■Montana Nebraska E Nevada■New Mexico■Oklahoma■Tennessee■Texas EUtah UWisconsin !Wyoming Quality Engineering Since 1965 13 2 Geotechnical Engineering Report Weld County Roads 49 and 52 Terracon Project No. 21005009 We appreciate being of service to you in the geotechnical engineering phase of this project, and are prepared to assist you during the construction phases as well. If you have any questions concerning this report or any of our testing, inspection, design and consulting services, please do not hesitate to contact us. Sincerely, .1/4%0V.%%%%% %%%%%% %%% %%%%%% yhl TERRACON a s�.` F%%%%%% 4 -s :`�_• _ tc Prepared by: a w q • I . I�� (f, < S M IEP • :,21„ e•�.+ Doug Leafg en, P.e. PP: s,o,aar ' Office Manager/Senior Geologist u Reviewed by: William J. Attwooll, P.E. Principal Copies to: Addressee (1) Todd Hodges Design (5) • iii I Fl TABLE OF CONTENTS j Page No. Letter of Transmittal ii iINTRODUCTION 1 3 PROPOSED CONSTRUCTION 1 II SITE EXPLORATION 2 Field Exploration 2 Laboratory Testing 2 ISITE CONDITIONS 3 SUBSURFACE CONDITIONS 3 Geology 3 Soil and.Bedrock Conditions 4 Field and Laboratory Test Results 4 Groundwater Conditions 5 jENGINEERING ANALYSES AND RECOMMENDATIONS 5 Geotechnical Considerations 5 Foundation Systems — Drilled Piers 6 Foundation Systems - Footings 6 • Basement Construction 8 Seismic Considerations 8 Floor Slab Design and Construction 9 Septic System Construction 10 I Earthwork 10 General Considerations 10 Site Preparation 10 I Fill Materials and Placement 11 Additional Design and Construction Considerations 12 Exterior Slab Design and Construction 12 ISurface Drainage 12 GENERAL COMMENTS 13 I I I . 'I 1 TABLE OF CONTENTS (Cont'd) ' APPENDIX A Site Plan Logs of Borings APPENDIX B -Laboratory Test Results APPENDIX C General Notes Unified Soil Classification 1 I 1 1 1 t 1 1 1 . 0 0 GEOTECHNICAL ENGINEERING REPORT UPROPOSED RESIDENTIAL SUBDIVISION WELD COUNTY ROADS 49 AND 52 KERSEY, COLORADO TERRACON PROJECT NO. 21005009 MAY 17, 2000 INTRODUCTION This report contains the results of our geotechnical engineering exploration for the proposed subdivision to be located near the intersection of Weld County Roads 49 and 52 near Kersey, Colorado. The site is located in the northeast quarter of Section 36, Township 5 North, Range 65 West of the 6th Principal Meridian. The purpose of these services is to provide information and geotechnical engineering recommendations relative to: • subsurface soil and bedrock conditions O • groundwater conditions • foundation design and construction • basement construction • floor slab design and construction • septic systems • earthwork • drainage The recommendations contained in this report are based upon the results of field and laboratory testing, engineering analyses, and experience with similar soil conditions, structures and our understanding of the proposed project. PROPOSED CONSTRUCTION As we understand it, the project will consist of developing the land to include nine residential lots that will be served by on-site sewage disposal systems. Additionally, two extra lots may be developed on the west side of the Gilmore Canal. Final grading plans were not available at the Ljtime of site exploration, although we assume cuts and fills of less than five feet generally. 3 0 Geotechnical Engineering Report Weld County Roads 49 and 52 Terracon Project No. 21005009 SITE EXPLORATION The scope of the services performed for this project included a site reconnaissance by an engineering geologist, a subsurface exploration program, laboratory testing and engineering analyses. Field Exploration A total of 75 test borings were drilled on the property between February 18 and March 27, 2000. Nine soil test borings were drilled near the center of assumed residential house locations to depths of 15 to 25 feet, and 66 borings were drilled in the area of proposed leach fields (6 borings per lot). Test boring locations for the foundation and percolation profile borings are shown on the Site Plan, Figure 1. Percolation tests were conducted in general accordance with Weld County requirements. All borings were advanced with a truck-mounted drilling rig, utilizing 4- and 6-inch diameter solid stem augers. The borings were located in the field by pacing from property lines and/or existing site features. The accuracy of boring locations should only be assumed to the level implied by the methods used. Lithologic logs of each boring were recorded by the engineering geologist during the drilling operations. At selected intervals, samples of the subsurface materials were taken by pushing thin- walled Shelby tubes, or by driving split-spoon and ring samplers. Penetration resistance measurements were obtained by driving the split-spoon into the subsurface materials with a 140-pound hammer falling 30 inches. The penetration resistance value is a useful index in estimating the consistency, relative density or hardness of the materials encountered. Groundwater conditions were evaluated in each boring at the time of site exploration, and three and seven days after the drilling. Laboratory Testing All samples retrieved during the field exploration were returned to the laboratory for observation by the project geotechnical engineer and were classified in accordance with the Unified Soil Classification System described in Appendix C. Samples of bedrock were classified in accordance with the general notes for Bedrock Classification. At that time, the field descriptions were confirmed or modified as necessary and an applicable laboratory testing program was formulated to determine engineering properties of the subsurface materials. Boring logs were prepared and are presented in Appendix A. 2 0 0 Geotechnical Engineering Report Weld County Roads 49 and 52 Terracon Project No. 21005009 Laboratory tests were conducted on selected soil and bedrock samples and are presented in Appendix B. The test results were used for the geotechnical engineering analyses, and the 0 development of foundation and earthwork recommendations. All laboratory tests were performed in general accordance with the applicable ASTM, local or other accepted standards. OSelected soil and bedrock samples were tested for the following engineering properties: • Water Content • Compressive Strength • Dry Density • Expansion • Consolidation SITE CONDITIONS The site is currently an agricultural field that is vegetated with corn stubble from the previous year. Surface drainage is fair toward the Gilmore Canal located west of the main development. Several oil field structures were located in the field that include an oil/gas well and tank batteries. Weld County Roads 49 and 52 border the property to the east and north, respectively. The agricultural field extends beyond the development to the south and west. The Gilmore canal meanders through the cornfield west of the main development. The two lots that may be developed west of the Gilmore Canal are vegetated with native grasses and shrubs. Surface drainage is poor to the Linorth. One oil/gas well is located near the center of this parcel, and a tank battery is located along the north portion of the property near the dividing line between the two lots. SUBSURFACE CONDITIONS Geology The proposed area is located within the Colorado Piedmont section of the Great Plains Q physiographic province. The Colorado Piedmont, formed during Late Tertiary and Early quaternary time (approximately 2,000,000 years ago), is a broad, erosional trench which separates the Southern Rocky Mountains from the High Plains. Structurally, the site lies along the western flank of the Denver Basin. During the Late Mesozoic and Early Cenozoic Periods (approximately 70,000,000 years ago), intense tectonic activity occurred, causing the uplifting of the Front Range and associated downwarping of the Denver Basin to the east. Relatively flat uplands and broad I�11 valleys characterize the present-day topography of the Colorado Piedmont in this region. The site is underlain by the Cretaceous Laramie Formation. The Laramie consists of interbedded 0 3 0 . LI Geotechnical Engineering Report Weld County Roads 49 and 52 Terracon Project No. 21005009 LIsandstone, siltstone and claystone units. Coal beds also occur within the Laramie, although we are not aware of any active or abandoned coalmines in the immediate vicinity of the property. DSoil and Bedrock Conditions flAs presented on the Logs of Boring, surface soils to depths of 2% to 13% feet consisted of silty sand and sandy lean clay. The materials underlying the surface soils and extending to the maximum depth of exploration consisted of sandstone/claystone bedrock. Field and Laboratory Test Results uField test results indicate that the clay soils vary from medium to stiff in consistency. The sand soils vary from loose to medium dense in relative density. The bedrock varies from soft to very Ehard in hardness. Laboratory test results indicate that the soils have non to low expansive potential. The claystone Qbedrock is moderately to highly expansive. Detailed percolation test results for each lot are presented in Appendix B. Percolation testing 0 conducted in the area of the proposed soil absorption beds are summarized as follows: . ° - Percalatiort t`estR esults Lot umb � ' nth ` , 3 a Soils $ ''fiAverag zV- ,L ;� ` S inches} assif radon i Percolbtwn R ate; e, .,_. 4 ,, s „Ain' f,M 51` r + (mint]tes/inch) ,.. 1 36 SM 54 2 36 SM 27 lj 3 36 SM 58 4 36 CL 105 5 36 SM 59 rdi 6 36 SM 46 7 36 CL 118 8 36 SM 48 9 36 SM 57 Lot A 36 CL 82 Lot B 36 SM 36 Field test results indicate the soils in the area of the proposed septic systems have poor to fair characteristics. S 4 L , r Geotechnical Engineering Report Weld County Roads 49 and 52 Terracon Project No. 21005009 Groundwater Conditions Groundwater was encountered in various borings at approximate depths of 4 to 23 feet in the test borings at the time of field exploration. When checked three to seven days after the drilling, groundwater was generally measured at approximate depths of 4 to 8 feet. These observations represent groundwater conditions at the time of the field exploration, and may not be indicative of other times, or at other locations. Groundwater levels can be expected to fluctuate with varying Li] � seasonal and weather conditions. u Zones of perched and/or trapped groundwater will occur at times in the subsurface soils overlying abedrock, on top of the bedrock surface or within permeable fractures in the bedrock materials. The location and amount of perched water is dependent upon several factors, including hydrologic conditions, type of site development, irrigation demands on or adjacent to the site, fluctuations in water features, seasonal and weather conditions. ENGINEERING ANALYSES AND RECOMMENDATIONS Geotechnical Considerations The site appears suitable for the proposed construction from a geotechnical engineering point of view. Potentially expansive bedrock and relatively shallow will require particular attention in the pdesign and construction. The following foundation systems were evaluated for use on the site: • grade beams and straight shaft piers drilled in to bedrock; • spread footings and/or grade beams bearing on undisturbed soils; and, • spread footings and/or grade beams bearing on engineered fill. Design criteria for alternative foundation systems is subsequently outlined. Use of the alternative foundation systems outlined in this report should be determined for individual residential structures on the basis of supplemental geotechnical exploration of each lot prior to construction. Slab-on-grade construction for basement or garage areas is considered acceptable for use when subgrade soils consist of the on-site soils and sandstone bedrock, provided that design and construction recommendations are followed. Given the engineering characteristics of the claystone bedrock, consideration should be given to use of structural floor systems in basement areas where these materials will be encountered. Evaluation of expansion tests conducted on individual lots 5 0 Geotechnical Engineering Report Weld County Roads 49 and 52 Terracon Project No. 21005009 during supplemental geotechnical exploration is recommended to assess the need for structural floor systems. Foundation Systems— Drilled Piers Due to the presence of moderate to highly expansive claystone bedrock on the site, a grade beam and drilled pier foundation system is recommended for support of proposed structures founded in u : or within 3 feet of the claystone bedrock. Straight shaft piers, drilled a minimum of 7 feet into firm or harder bedrock, with a minimum shaft length of 23 feet are recommended. For axial compression loads, piers may be design for a maximum end-bearing pressure of 25,000 pounds per square foot (psf), and skin friction of 2,500 psf for the portion of the pier in firm or harder bedrock. • 1 A minimum practical horizontal spacing between piers of at least three diameters should be maintained, and adjacent piers should bear at the same elevation. Piers should be considered to work in group action if the horizontal spacing is less than three pier diameters. The capacity of individual piers must be reduced when considering the effects of group action. Capacity reduction is a function of pier spacing and the number of piers within a group. If group action analyses are necessary, capacity reduction factors can be provided for the analyses. Required pier penetration should be balanced against potential uplift forces due to expansion of the subsoils and bedrock on the site. For design purposes, the uplift force on each pier can be determined on the basis of the following equation: Up = 25xD Where: Up = the uplift force in kips, and D = the pier diameter in feet Uplift forces on piers should be resisted by a combination of dead-load and pier penetration below a depth of 7 feet and in the bearing strata. Al All piers should be reinforced full depth for the applied axial, lateral and uplift stresses imposed. the amount of reinforcing steel for expansion should be determined by the tensile force created by the uplift force on each pier, with allowance for dead-load. Minimum reinforcement of at least one- half percent of the cross-sectional area of each pier should be specified. lr��r 6 axis U Geotechnical Engineering Report Weld County Roads 49 and 52 Terracon Project No. 21005009 To reduce potential uplift forces on piers, use of long grade beam spans to increase individual pier loading, and small diameter piers are recommended. Use of a minimum pier diameter of 10 inches is recommended. A minimum 4-inch void space should be provided beneath grade beams between piers. The void material should be of suitable strength to support the weight of fresh concrete used in grade beam construction, and to avoid collapse when foundation backfill is placed. Pier concrete should have a relatively high fluidity with slump in the range of 5 to 7 inches is recommended. Drilling to design depths should be possible with conventional single flight power augers. Groundwater conditions indicate that temporary steel casing may be required to properly drill and Uclean piers prior to concrete placement. Groundwater should be removed from each pier hole prior to concrete placement. Pier concrete should be placed immediately after completion of drilling and cleaning. If pier concrete cannot be placed in dry conditions, a tremie should be used for concrete placement. Due to potential sloughing and raveling, foundation concrete quantities may exceed calculated geometric volumes. If casing is used for pier construction, it should be withdrawn in a slow continuous manner maintaining a sufficient head of concrete to prevent infiltration of water or the creation of voids in pier concrete. To provide increased resistance to potential uplift forces, the sides of each pier should be mechanically roughened in the bearing strata. This should be accomplished by a roughening tooth placed on the auger. Pier bearing surfaces must be cleaned prior to concrete placement. A representative of the geotechnical engineer should inspect the bearing surface and pier configuration. Foundation Systems - Footings Due to the presence of non- to low-swelling soils on portions of the site, spread footing foundations bearing upon undisturbed subsoils, sandstone bedrock and/or engineered fill are recommended for support for the proposed structure that are placed a minimum of 3 feet above the claystone bedrock. The footings may be designed for a maximum bearing pressure of 1,500 psf. Additionally, the footings should be designed to maintain a minimum bearing pressure of 500 psf. ICI The design bearing pressure applies to dead loads plus design live load conditions. The design bearing pressure may be increased by one-third when considering total loads that include wind or Fel seismic conditions. n 7 j Q Geotechnical Engineering Report Weld County Roads 49 and 52 Terracon Project No. 21005009 Exterior footings should be placed a minimum of 30 inches below finished grade for frost protection and to provide confinement for the bearing soils. Finished grade is the lowest adjacent grade for perimeter footings. rr Footings should be proportioned to reduce differential foundation movement. Proportioning on the basis of equal total settlement is recommended; however, proportioning to relative constant dead- load pressure will also reduce differential settlement between adjacent footings. Total settlement a. resulting from the assumed structural loads is estimated to be on the order of 3/4 inch or less. a Differential settlement should be on the order of 1/2 to 3/4 of the estimated total settlement. Additional foundation movements could occur if water from any source infiltrates the foundation soils; therefore, proper drainage should be provided in the final design and during construction. a Foundations and masonry walls should be reinforced as necessary to reduce the potential for distress caused by differential foundation movement. The use of joints at openings or other discontinuities in masonry walls is recommended. Foundation excavations should be observed by the geotechnical engineer. If the soil conditions encountered differ significantly from those presented in this report, supplemental recommendations will be required. Basement Construction Groundwater was encountered throughout the majority of the site at a depths of 4 to 8 feet below existing grade. Full-depth basement construction is considered feasible on the site provided that the basement subgrade is placed a minimum of 3 feet above the groundwater. To reduce the potential for groundwater to enter the basement of the structure, installation of a dewatering system is recommended. The dewatering system should, at a minimum, include an underslab gravel drainage layer sloped to an interior perimeter drainage system. The drainage system should consist of a properly sized perforated pipe, embedded in free-draining gravel, placed in a trench at least 12-inches in width. The trench should be inset from the interior edge of the nearest foundation a minimum of 12-inches. Gravel should extend a minimum of 3- inches beneath the bottom of the pipe. The drainage system should be sloped at a minimum 1/8 inch per foot to a suitable outlet, such as a sump and pump system. Seismic Considerations LiThe project site is located in Seismic Risk Zone I of the Seismic Zone Map of the United States as indicated by the 1997 Uniform Building Code. Based upon the nature of the subsurface materials, 0 8 0 0 Geotechnical Engineering Report Weld County Roads 49 and 52 Terracon Project No. 21005009 a soil profile type S. should be used for the design of structures for the proposed project (1997 Uniform Building Code, Table No. 16-J). Floor Slab Design and Construction Slab on grade construction is considered feasible when the subgrade soils consist of on-site soils and the slab is placed a minimum of 4 feet above the claystone bedrock. However, the expansive potential of the claystone bedrock at approximate slab subgrade elevation could result in differential movement of floor slab-on-grade should the bedrock become elevated in moisture content. Differential slab movement on the order of 1 to 2 inches or more is possible. Use of structural floor systems, structurally supported independent of the subgrade soils, is a positive means of eliminating the potentially detrimental effects of floor movement. If slab-on-grade is utilized, the subgrade soils should be prepared as outlined in the earthwork section of this report. A common practice to reduce potential slab heave involves overexcavation of the expansive soils and replacing these materials with non-expansive imported fill. This alternative will not eliminate the possibility of slab heave; but movements should be reduced and tend to be more uniform. Additional floor slab design and construction recommendations are as follows: • Positive separations and/or isolation joints should be provided between slabs and all foundations, columns or utility lines to allow independent movement. • Control joints should be provided in slabs to control the location and extent of cracking. • A minimum 2-inch void space should be constructed above, or below non-bearing partition walls placed on the floor slab. Special framing details should be provided at adoor jambs and frames within partition walls to avoid potential distortion. Partition walls should be isolated from suspended ceilings. • Interior trench backfill placed beneath slabs should be compacted in accordance with recommended specifications outlined below. IJ • In areas subjected to normal loading, a minimum 4-inch layer of clean-graded gravel should be placed beneath interior slabs. For heavy loading, reevaluation of slab and/or base course thickness may be required. ICI 9 � 3 Geotechnical Engineering Report Weld County Roads 49 and 52 Terracon Project No. 21005009 • A minimum 8-inch layer of free-draining gravel should be placed beneath basement floor slabs in conjunction with the underslab drainage system. • If moisture sensitive floor coverings are used on interior slabs, consideration should be given to the use of barriers to minimize potential vapor rise through the slab. • Floor slabs should not be constructed on frozen subgrade. Septic System Construction Field test results indicate that standard septic systems are feasible for construction on several of the proposed lots. The systems should be designed in accordance with applicable state and county requirements and should be located at the minimum distances from all pertinent ground features described in Weld County regulations. On lots with acceptable percolation rates groundwater or bedrock may be limiting factors for absorption bed construction. In all cases, the bottom of the absorption bed must be placed a minimum of 4 feet above groundwater or bedrock. Due to fluctuations of the groundwater by perched water and irrigation of crops at the property, we recommend that a test boring or backhoe test pit be observed to determine the depth to groundwater on each lot immediately prior to the installation of septic systems. Earthwork General Considerations The following presents recommendations for site preparation, excavation, subgrade preparation and placement of engineered fills on the project. All earthwork on the project should be observed and evaluated by Terracon. The fl evaluation of earthwork should include observation and testing of engineered fill, subgrade preparation, foundation bearing soils, and other geotechnical conditions exposed during the construction of the project. Site Preparation Strip and remove existing vegetation, debris, and other deleterious materials from proposed building and pavement areas. All exposed surfaces should be free of mounds and depressions which could prevent uniform compaction. 0 10 0 Geotechnical Engineering Report Weld County Roads 49 and 52 Terracon Project No. 21005009 Stripped materials consisting of vegetation and organic materials should be wasted from the site, or used to revegetate landscaped areas or exposed slopes after completion of grading operations. If unexpected fills or underground facilities are encountered, such features should be removed and the excavation thoroughly cleaned prior to backfill placement and/or construction. It is anticipated that excavations for the proposed construction can be accomplished with conventional earthmoving equipment. If excavations need to penetrate into the competent sandstone bedrock, ripping or jack-hammering may be needed to advance the excavation. Depending upon depth of excavation and seasonal conditions, groundwater may be encountered in excavations on the site. Pumping from sumps may be utilized to control water within excavations. Well points may be required for significant groundwater flow, or where excavations penetrate groundwater to a significant depth. The individual contractor(s) is responsible for designing and constructing stable, temporary excavations as required to maintain stability of both the excavation sides and bottom. All excavations should be sloped or shored in the interest of safety following local, and federal regulations, including current OSHA excavation and trench safety standards. Fill Materials and Placement Clean on-site soils or approved imported materials may be used as fill material. On-site bedrock materials are not recommended for use as compacted fill beneath interior or exterior floor slabs. Imported soils (if required) should conform to the following: Percent fines by weight Gradation fASTM C1361 6" 100 3" 70-100 No. 4 Sieve 50-100 No. 200 Sieve 60 (max)rai • Liquid Limit 30 (max) Li 11 0 Geotechnical Engineering Report Weld County Roads 49 and 52 Terracon Project No. 21005009 • Plasticity Index 15 (max) Engineered fill should be placed and compacted in horizontal lifts, using equipment and procedures that will produce recommended moisture contents and densities throughout the lift. Recommended compaction criteria for engineered fill materials are as follows: Minimum Percent Material (ASTM D6981 Scarified subgrade soils 95 On-site and imported fill soils: Beneath foundations 95 Beneath slabs 95 On-site or imported clay soils should be compacted within a moisture content range of 2 percent below, to 2 percent above optimum. Granular soils should be compacted within a moisture range of 3 percent below to 3 percent above optimum unless modified by the project geotechnical engineer. Additional Design and Construction Considerations Exterior Slab Design and Construction OExterior slabs-on-grade, exterior architectural features, and utilities founded on, or in backfill may experience some movement due to the volume change of the backfill. Potential movement could be reduced by: • minimizing moisture increases in the backfill . controlling moisture-density during placement of backfill • using designs which allow vertical movement between the exterior features and adjoining structural elements • placing effective control joints on relatively close centers Surface Drainage Positive drainage should be provided during construction and maintained throughout the life of the proposed project. Infiltration of water into utility or foundation excavations must be prevented during construction. Planters and other surface features which could retain water 12 • Geotechnical Engineering Report Weld County Roads 49 and 52 Terracon Project No. 21005009 in areas adjacent to the building or pavements should be sealed or eliminated. In areas where sidewalks or paving do not immediately adjoin the structure, we recommend that protective slopes be provided with a minimum grade of approximately 10 percent for at least 10 feet from perimeter walls. Backfill against footings, exterior walls, and in utility and sprinkler line trenches should be well compacted and free of all construction debris to reduce the possibility of moisture infiltration. Downspouts, roof drains or scuppers should discharge into splash blocks or extensions when the ground surface beneath such features is not protected by exterior slabs or paving. Sprinkler systems should not be installed within 5 feet of foundation walls. Landscaped irrigation adjacent to the foundation system should be minimized or eliminated. GENERAL COMMENTS Terracon should be retained to review the final design plans and specifications so comments can be made regarding interpretation and implementation of our geotechnical recommendations in the design and specifications. Terracon also should be retained to provide testing and observation during excavation, grading, foundation and construction phases of the project. The analysis and recommendations presented in this report are based upon the data obtained from the borings performed at the indicated locations and from other information discussed in this report. This report does not reflect variations which may occur between borings or across the site. The nature and extent of such variations may not become evident until construction. If variations appear, it will be necessary to reevaluate the recommendations of this report. The scope of services for this project does not include either specifically or by implication any environmental assessment of the site or identification of contaminated or hazardous materials or conditions. If the owner is concerned about the potential for such contamination, other studies should be undertaken. t� This report has been prepared for the exclusive use of our client for specific application to the project discussed and has been prepared in accordance with generally accepted geotechnical engineering practices. No warranties, either express or implied, are intended or made. In the event that changes in the nature, design, or location of the project as outlined in this report, are planned, the conclusions and recommendations contained in this report shall not be considered valid unless Terracon reviews the changes, and either verifies or modifies the conclusions of this report in writing. 0 0 13 WELD COUNTY ROAD 52 LOT A LOT B• , ci:i. Lo H9 LOT o. 9S h7o.20� lion ale Hai Hai L-81 73 S !ma Hal Ha& y S IS (------ . Z xal mu L . r `°T' mm Ala wre \ cars ®S ' Hall Leta S xe•a LOTT II O C Q D a as (.O \z. Grill IPS • c1 titi it a a \ . 0 0 BORING LOCATION PLAN ' NI PROPOSED RESIDENTIAL SUBDIVISION WELD COUNTY ROADS 4B AND 52 KERSEY.COLORADO FORP&ATURI0:YFARMS T �8 DML rr n 21005009 _ 1289 FIRST AVENUE Da% 5-15-00 'wis FORawaLOrwr+smoeTIONruawyES ON ONLY, A *MSS DML GREELEY•COLORADO 80831 p�—,ivica DML Rawl lb. 1 • • [J i LOG OF BORING No. 1 Page 1 of 1 t] CLIENT ARCHITECT/ENGINEER P & A Turkey Todd Hodges Design SITE Weld County Roads 49 and 52 PROJECT Kersey, Colorado Proposed 9 Lot Subdivision SAMPLES TESTS O • L-. F w > n z= a Li M DESCRIPTION w Z� w z� .aa I'1 pia w c ] > w a� aU zFcn 3acn I C7 0 Z F a: rnal ,4 Ma. Conn. cna.a. I� 1/4^‘.". 0.5 TOPSOIL 6" _SM 1 SS 18" 10 10 SILTY SAND lij 2.5 Tan, moist, loose ,< WEATHERED _ 2 ST 12" 17 118 785 SANDSTONE/CLAYSTONE Gray to tan, moist, soft 3 SS 12" 28 18 5 N— 6.0 — SANDSTONE/CLAYSTONE Gray to tan, moist y - 4 ST 12" 19 107 13765 300 Hard to very hard = _ 5 SS 12" 45 19 _ 10- O - 6 SS 10" 50/.8 18 15 20- 0 = - 4 - 24.5 SS 6" 50/ 5 I BOTTOM OF BORING 0 THE STRATIFICATION LINES REPRESENT THE APPROXIMATE BOUNDARY LINES BETWEEN SOIL AND ROCK TYPES: IN-SITU,THE TRANSITION MAY BE GRADUAL. WATER LEVEL OBSERVATIONS BORING STARTED 2-25-00 WL Q 23.0' W.D. _ 8.0' A.B. BORING COMPLETED 2-25-00 WL lie rr acon RIG CME-55 FOREMAN DBC • WL Water Checked 3 Days A.B. APPROVED DMI, 10Ba 21005009 a QLOG OF BORING No. 2 Page l of'CLIENT ARCHITECT/ENGINEER P & A.Turkey Todd Hodges Design SITE Weld County Roads 49 and 52 PROJECT Kersey, Colorado Proposed 9 Lot Subdivision SAMPLES TESTS O s- s r 0 o t x c4 - z wF w DESCRIPTION x ill w Z� a w ZO° 0 a H O xi III 0 FO O rw UCv, u.4 Z >-. a va'ien z AaU. �c/Iiat. 0.5 TOPSOIL 6" _SM SILTY SAND 2.5 Tan, moist, loose O WEATHERED _ SANDSTONE/CLAYSTONE — Gray to tan, moist, soft Lj \_ 6.0 — SANDSTONE/CLAYSTONE Gray to tan, moist 1 SS 12" 33 22 8.0 Hard to very hard BOTTOM OF BORING S . 0 0 S S S THE STRATIFICATION LINES REPRESENT THE APPROXIMATE BOUNDARY LINES BETWEEN SOIL AND ROCK TYPES: IN-SITU,THE TRANSITION MAY BE GRADUAL. WATER LEVEL OBSERVATIONS BORING STARTED 2-25-00 j L; WL 4 None W.D. ? None A.B. BORING COMPLETED 2-25-00 WL I 1 [err acon RIG CME-55 FOREMAN DBC WL Water Checked 3 Days A.B. APPROVED DMI, JOB a 21005009 t LOG OF BORING No. 3 Page 1 of 1 " CLIENT ARCHITECT/ENGINEER P & A Turkey Todd Hodges Design ill SITE Weld County Roads 49 and 52 PROJECT Kersey, Colorado Proposed 9 Lot Subdivision SAMPLES TESTS p O F w I C z Z=E- W ' E DESCRIPTION >s m z� 5 w zc7 �j ad W -Ica cG w ca > ). W as O aU 44--w 3a� C7 Z E- a: in= a Oa Ocna cna.a. 0.5 TOPSOIL 6" _SM 1 SS 18" 9 12 SILTY SAND — Brown to tan, moist, loose _— 1 2 ST 12" 9 116 — - 3 SS 12" 7 14 107 5 7.0 — C WEATHERED SANDSTONE _ Gray to tan, moist, soft S /x' 10.0 - 4RSI 12"I 45 25I 0 10 SANDSTONE/CLAYSTONE Gray to tan, moist -- I Hard to very hard . 5 SS 10" 50/.8 23 15 - 6 SS 11" 50/.9 23 20 I -,_ __ - ns 24.8 _ 7 SS 10" 50/.8 27 BOTTOM OF BORING [ .1 5 THE STRATIFICATION LINES REPRESENT THE APPROXIMATE BOUNDARY LINES BETWEEN SOIL AND ROCK TYPES: IN-SITU,THE TRANSITION MAY BE GRADUAL. WATER LEVEL OBSERVATIONS BORING STARTED 2-25-00 cii WL 4 8.0' W.D. = 8.0' A.B. BORING COMPLETED 2-25-00 x WL ir err acon RIG CME-55 FOREMAN DBC WL Water Checked 3 Days A.B. APPROVED DM1, JOB// 21005009 li I LOG OF BORING No. 4 Page 1 of 1 CLIENT ARCHITECT/ENGINEER P & A Turkey Todd Hodges Design SITE Weld County Roads 49 and 52 PROJECT E . Kersey, Colorado Proposed 9 Lot Subdivision SAMPLES TESTS F camU Re a z [%,E- O O ZT DESCRIPTION w > z� O w z0 a¢¢ ca 3 F a z cG a. cci � 0.>-. U HO p >u• 0 1,, C7 M O Z F a �m ,4 Asa.. �ccna ^ 0.5 TOPSOIL 6" _SM SILTY SAND — Tan, moist, loose — I 5 _ 6.5 — I I WEATHERED — 8.0 SANDSTONE/CLAYSTONE ? - 1 SS ! 12"i 23 25 \Gray to tan, moist, soft BOTTOM OF BORING I • • 0 Lil ' Q : D THE STRATIFICATION LINES REPRESENT THE APPROXIMATE BOUNDARY LINES BETWEEN SOIL AND ROCK TYPES: IN-SITU,THE TRANSITION MAY BE GRADUAL. WATER LEVEL OBSERVATIONS BORING STARTED 2-25-00 WL g None W.D. 2 7.5' A.B. BORING COMPLETED 2-25-00 WL 1lerr acon RIG CME-55 FOREMAN DBC WL Water Checked 3 Days A.B. APPROVED Div, JOB// 21005009 • LOG OF BORING No. 5 Page 1 of 1 CLIENT ARCHITECT/ENGINEER P & A Turkey Todd Hodges Design SITE Weld County Roads 49 and 52 PROJECT Kersey, Colorado Proposed 9 Lot Subdivision SAMPLES TESTS o C) b\ F 1 ccu Lill ' Oa l - n Z I ZEE-• W DESCRIPTION x Cn m i W Z� M a 'z0 ,-I co C7 O E Z E- . G (Aga 2 no. :Ocna coa.a. 0.5 TOPSOIL 6" SM 1 SS . 18" 7 11 SILTY SAND — Brown to tan, moist, loose I 3.5 _ • WEATHERED CLAYSTONE 2 RS; 12" 21 28 94 ' 700 Gray, moist, soft 5 7.5 V - 3 ST: 12" 191 112 11000 CLAYSTONE _ 4I SS 12" 37 19 Gray, moist • 10.0 Moderately hard to hard Q 10- SANDSTONE/CLAYSTONE - ' Gray to tan, moist • Hard to very hard = • • _ 5 SS 12" 50 141 • 15 • • • 20— I I 24.8 - 6 SS 110" 50/.8 23 BOTTOM OF BORING I I I rjTHE STRATIFICATION LINES REPRESENT THE APPROXIMATE BOUNDARY LINES BETWEEN SOIL AND ROCK TYPES: IN SITU,THE TRANSITION MAY BE GRADUAL. WATER LEVEL OBSERVATIONS - BORING STARTED 2-25-00 raj WI- 4 10.0' W.D.1? 7.5� A.B. BORING COMPLETED 2-25-00 WL 1 11'err acon RIG CME-55 FOREMAN DBC rij WL Water Checked 3 Days A.B. APPROVED DML J0B 11 21005009 LOG OF BORING No. 6 Page 1 of 1 CLIENT ARCHITECT/ENGINEER P & A Turkey Todd Hodges Design SITE Weld County Roads 49 and 52 PROJECT Kersey, Colorado Proposed 9 Lot Subdivision SAMPLES TESTS .a FQ v >' w F, zx U DESCRIPTION tr w a z Z- z x = > zul w zz ¢a 0 (.� P. OU E.,© 5 �u. OCtL GC O Z F n va,aa7 Oa ]via ^ 0.5 TOPSOIL 6" _SM SILTY SAND — Tan, moist, loose 3.5 — WEATHERED SANDSTONE/CLAYSTONE Gray to tan, moist, soft 5- a A 8.0 ? - 1 SS 12" 27 IS BOTTOM OF BORING O K _h O II O THE STRATIFICATION LINES REPRESENT THE APPROXIMATE BOUNDARY LINES BETWEEN SOIL AND ROCK TYPES: IN-SITU,THE TRANSITION MAY BE GRADUAL. WATER LEVEL OBSERVATIONS BORING STARTED 2-25-00 WL I4 None W.D. L 7.5' A B 1 [err ac®r� RIG RING COMPLETED 2-25-00 WL I CME-55 FOREMAN DBC FWL I Water Checked 3 Days A.B. APPROVED DML JOB// 21005009 I LOG OF BORING No. 7 Page 1 of 1 ICLIENT ARCHITECT/ENGINEER P & A Turkey Todd Hodges Design I SITE Weld County Roads 49 and 52 PROJECT Kersey, Colorado Proposed 9 Lot Subdivision SAMPLES TESTS s H w x DESCRIPTION x ti 9: t I% ae z ri..E. 0,t LU > Zvt F q Zpz �� VI w 0V, = r LUU cc..- .0 ZFcBn 3C� C Z F C vIW Ca acna cnac, 0.5 TOPSOIL 6" _ CL 1 SS 18" 7 9 1 / - SANDY LEAN CLAY %i Brown to gray, moist, stiff �% _ 2 SS 12" 9 21 96 /�:- 5 7.0 - - 3 ST 12" 1730 580 , WEATHERED CLAYSTONE ��,• 9.0 Gray, moist, soft — 4 SS 12" 30 I 191 \�`�Sc 9'8 CLAYSTONE 10— Gray, moist Moderately hard to hard I SANDSTONE/CLAYSTONE - i Gray to tan, moist Hard to very hard - 15.0 _ 5 SS 12"I 45 1 161 BOTTOM OF BORING 15 1 I I I THE STRATIFICATION LINES REPRESENT THE APPROXIMATE BOUNDARY LINES TTT BETWEEN SOIL AND ROCK TYPES: INSITU,THE TRANsmON MAY BE GRADUAL. WATER LEVEL OBSERVATIONS BORING STARTED 2-25-00 iWL Q None W.D. Y. None A.B. BORING COMPLETED 2-25-00 i WL l �erracon RIG CME-55 FOREMAN DBC IWL Water Checked 3 Days A.B. APPROVED DML JOB s 21005009 l 0 : LOG OF BORING No. 8 Page 1 of 1 CLIENT ARCHITECT/ENGINEER P & A Turkey Todd Hodges Design SITE Weld County Roads 49 and 52 PROJECT • Kersey, Colorado Proposed 9 Lot Subdivision a SAMPLES TESTS O O H W )- t va Z zm x DESCRIPTION x cm W > z ] IZI z(7 0., U ora ac a.W OU F0 en QtL OU Car., Lu i' O O Z Z F a anal Aa. Zcnna 0.5 TOPSOIL 6" _SM SANDY LEAN CLAY _ Tan, moist, stiff = _ 5- 0, . _ 8.0 — CL 1 SSr 12"I 9 15 (a BOTTOM OF BORING I ! I I� i I I I i H ciii g THE STRATIFICATION LINES REPRESENT THE APPROXIMATE BOUNDARY LINES 1 BETWEEN SOIL AND ROCK TYPES: IN-SITU,THE TRANSITION MAY BE GRADUAL. WATER LEVEL OBSERVATIONS BORING STARTED 2-25-00 liWL 5? None µ'•D• ? None A.B. � I' GmGCOMPLETED 2-25-00 WL err acon RI CME-55 FOREMAN DBC Ili WL Water Checked 3 Days A.B. APPROVED DML JOB N 21005009 I LOG OF BORING No. 9 Page 1 of 1 pCLIENT ARCHITECT/ENGINEER P & A Turkey Todd Hodges Design SITE Weld County Roads 49 and 52 PROJECT Kersey, Colorado Proposed 9 Lot Subdivision o .a SAMPLES TESTS ijE-: M ' t ' to FA Z x W a DESCRIPTION x >" w I > z\ W ZU C �' m �' t- c z �� ti. E U (Om Mo.., Ina. cna,a. ^ 0.5 TOPSOIL 6" _SM 1 SS I 18" 5 10 SILTY SAND - Brown to tan, moist to wet, loose I 2 ST i 12" 11 79 3 55112" 4 14 5 8.5 . _ I 4 SS. 12" 12 17I 1020 WEATHERED CLAYSTONE/SANDSTONE 10— Gray, moist, soft — I • 12.0 _ CLAYSTONE/SANDSTONE Gray,moist, hard — i 15.0— — 5 SS 12" 50 20 BOTTOM OF BORING 15 I I 2. as , I i a � THE STRATIFICATION LINES REPRESENT THE APPROXIMATE BOUNDARY LINES , BETWEEN SOIL AND ROCK TYPES: INSITU,THE TRANSITION MAY BE GRADUAL. WATER LEVEL OBSERVATIONS BORING STARTED 2-18-00 WL 4 7,7' W.D.II 7.0' A.B. 1err2con RIG BORING COMPLETED 2-18-00 � e WL i CME-55 FOREMAN DBC WL Water Checked 7 Days A.B. APPROVED DML JOB It 21005009 I I 0 OLOG OF BORING No. 10 Page 1 of 1 CLIENT ARCHITECT/ENGINEER P & A Turkey Todd Hodges Design I SITE Weld County Roads 49 and 52 PROJECT Kersey, Colorado Proposed 9 Lot Subdivision SAMPLES TESTS U • W )" I zx x DESCRIPTION w w a El a. a 6 a l o Zen °� i ow 0 w cn o Owl., o a z F I z vw Qaa.. cna ( 0.5 TOPSOIL 6" _SM SILTY SAND Tan, moist to wet, medium dense 5_ i 0 . Y 8.0 — 1 SS i 12"I 18 14 BOTTOM OF BORING • 1 0 . I 0 i 0 ; 0 ' 0 , i J THE STRATIFICATION LINES REPRESENT THE APPROXIMATE BOUNDARY LINES BETWEEN SOIL AND ROCK TYPES: IN-SITU,THE TRANSITION MAY BE GRADUAL. WATER LEVEL OBSERVATIONS BORING STARTED 2-18-00 iiiii WL `? None W.D. X. MI A.B. � ��rr acon RIG BORING COMPLETED 2-18-00 WL CME-55 FOREMAN DBC WI- Water Checked 7 Days A.B. APPROVED DML JOB# 21005009 1 0 LOG OF BORING No. 11 Page 1 of 1 0 CLIENT ARCHITECT/ENGINEER P & A Turkey Todd Hodges Design r SITE Weld County Roads 49 and 52 PROJECT Kersey, Colorado Proposed 9 Lot Subdivision SAMPLES r TESTS ° x t f4 cii cc Z ZF a U DESCRIPTION x cc l > Z� Fes, p �z ,-] F., �„ I W ° .3 � w '-w Uxw 01 a w � � � w aF.� ° aU ZE-�n A A Z I F G CnC6 .4 I Aa. �fna. vlaa 0.5 TOPSOIL 6" _SM 1 { SS 18" 6 13 SILTY SAND I i — Tan, moist, loose _ 2I ST NR 3 ( 5S 12" 4 13 ( • 5 - 7.0 - WEATHERED i 1 0 - 4 SS 12" 11 1035 CLAYSTONE/SANDSTONE Gray to tan, moist, soft 27 10_ I12.0 _ i , I SANDSTONE/CLAYSTONE . Gray to tan, moist, hard 5I SS 12" 25 191 = Er 15 _ a =re = I 1 20- 6 SS 12" 50 161 25.0 25 iBOTTOM OF BORING THE STRATIFICATION LINES REPRESENT THE APPROXIMATE BOUNDARY LINES - BETWEEN SOIL AND ROCK TYPES: IN-SITU,THE TRANSITION MAY BE GRADUAL. WATER LEVEL OBSERVATIONS BORING STARTED 2-18-00 �,f WL U. None W.D. 1 None A.B. BORING COMPLETED 2-18-00 WL ' 1 ierr acon RIG CME-55 I FOREMAN DBC WL Water Checked 7 Days A.B. APPROVED DAIL I JOB// 21005009 Si LOG OF BORING No. 12 Page 1 of 1 CLIENT ARCHITECT/ENGINEER P & A Turkey Todd Hodges Design SITE Weld County Roads 49 and 52 PROJECT Kersey, Colorado Proposed 9 Lot Subdivision c7 .a SAMPLES TESTS F O F W �" Z ZH x DESCRIPTION w Z� to z0 ¢ a V a V • 3 a A °LU a0 a cLo zFvu'i O Q O Z E^ toro Qa'An a na ^ ^ 0.5 TOPSOIL 6" _SM SILTY SAND Tan, moist, loose _ 5— 7.5 1 SS 12" 9 20 /C SU WEATHERED CLAYSTONE \Gray, moist, soft ' BOTTOM OF BORING O fr • ill THE STRATIFICATION LINES REPRESENT THE APPROXIMATE BOUNDARY LINES BETWEEN SOIL AND ROCK TYPES: IN-SITU,THE TRANSITION MAY BE GRADUAL. WATER LEVEL OBSERVATIONS BORING STARTED 2-18-00 WL Q None W.D. ? None A.B. 1 IWI BORING COMPLETED 2-18-00 WL e rr acon RIG CME-55 FOREMAN DBC WL Water Checked 7 Days A.B. APPROVED DM', JOB# 21005009 0 LOG OF BORING No. 13 Page 1 of 1 Clil CLIENT ARCHITECT/ENGINEER P & A Turkey Todd Hodges Design SITE Weld County Roads 49 and 52 PROJECT Kersey, Colorado Proposed 9 Lot Subdivision ,-.1 SAMPLES TESTS E � � � >- ti; Zx W DESCRIPTION m > Z� 5 m ZO a a. o ] a. O F•O p aw Zcai. UWIz, A A Z F c4 Grum ,4 Aaa..� Xola. cnaa. I i0.5 TOPSOIL 6" _CL 1 SS 18" 7 11 P SANDY LEAN CLAY — Brown to tan,moist to wet, medium — _ _ 21 SS 12" 5 18 •0 5 - 8.0 - 3 1ST 12" 201 114 WEATHERED d I 4 j SS 12" 27 201 I SANDSTONE/CLAYSTONE 10.5 Gray to tan, moist, soft 10— ! SANDSTONE/CLAYSTONE — Gray to tan, moist — Hard to very hard _ 5 SS 12" 45 17 15 IE' - - 20— I * — s — 24.6 6 SS 7" 50/.6 21 BOTTOM OF BORING II THE STRATIFICATION LINES REPRESENT THE APPROXIMATE BOUNDARY LINES BETWEEN SOIL AND ROCK TYPES: IN-SITU,THE TRANSITION MAY BE GRADUAL. WATER LEVEL OBSERVATIONS BORING STARTED 2-18-00 WL I2 ,5 0' W.D. = 5.0' A.E. BORING COMPLETED 2-18-00 WL I ir err acon RIG. CME-55 FOREMAN DBC WL i Water Checked 7 Days A.B. APPROVED DMI, JOB// 21005009 Er 1 lei LOG OF BORING No. 14 Page 1 of 1 CLIENT ARCHITECT/ENGINEER P & A Turkey Todd Hodges Design SITE Weld County Roads 49 and 52 PROJECT Kersey, Colorado Proposed 9 Lot Subdivision SAMPLES TESTS a O F w �' ui �, zx C_) DESCRIPTION wce w W.F. a x p z F A zz a 6 a O 3 � . oW a w rn a ›.. [MI a,� O go zu:[t. F� A Z F CL (nal a Oa. Mona. ^ 0.5 TOPSOIL 6" _ CL / SANDY LEAN CLAY — %�; — Tan, moist to wet, stiff :' / — 5 / 7.5 15S12" 21 24 :U/� S 0 WEATHERED CLAYSTONE/SANDSTONE Gray to tan, moist, soft 7 BOTTOM OF BORING O Li THE STRATIFICATION LINES REPRESENT THE APPROXIMATE BOUNDARY LINES BETWEEN SOIL AND ROCK TYPES: INSITU,THE TRANSrrION MAY BE GRADUAL. �tI'111++� WATER LEVEL OBSERVATIONS BORING STARTED 2-18-00 flWI- 4 4.0' W.D. 1 4.0' A.B. BORING COMPLETED 2-18-00 WL 1 err acon RIG DBC CME-55 FOREMAN WI- Water Checked 7 Days A.B. APPROVED DM', JOB// 21005009 LOG OF BORING No. 15 Page 1 of 1 CLIENT ARCHITECT/ENGINEER P & A Turkey Todd Hodges Design tat SITE Weld County Roads 49 and 52 PROJECT li Kersey, Colorado Proposed 9 Lot Subdivision .a SAMPLES TESTS • °a t w o MI F La a Z r:E" cG X DESCRIPTION x co m > Zen F p I ccoZ --Iva, m 0 =°� o a0 zFcn Wilk,. La —rn C7 0 a Z F c cnm 2 Oa. Dona. m.o. 0.5 TOPSOIL 6" _SM I SS 18" 8 12 M SILTY SAND — Brown to tan, moist to wet, loose — - 2 ST 12" 12 107 0 - 3 SS 12" 5 15 I 5 S - 4 ST 121 _ 5 SS 12" 9 22 i 10- i I 13.5 WEATHERED CLAYSTONE 15.0 Gray, moist, soft to moderately hard — 6 SS 112" 24 21 IBOTTOM OF BORING 15 I 11 I I THE STRATIFICATION LINES REPRESENT THE APPROXIMATE BOUNDARY LINES BETWEEN SOIL AND ROCK TYPES: IN-SITU.THE TRANSITION MAY BE GRADUAL. WATER LEVEL OBSERVATIONS BORING STARTED 2-18-00 rilWL 4 7,5' W.D. 1 7,5' A.B. BORING COMPLETED 248-00 WL ir err acon RIG CME_55 I FOREMAN DBC WL Water Checked 7 Days A.B. APPROVED DML I JOB// 21005009 LOG OF BORING No. 16 Page 1 of 1 CLIENT ARCHITECT/ENGINEER P & A Turkey Todd Hodges Design SITE Weld County Roads 49 and 52 PROJECT Kersey, Colorado Proposed 9 Lot Subdivision SAMPLES TESTS O O W 11 >' turn' wEx-' x DESCRIPTION to j z- ] w z0 a¢ F4 Cn pa F CI z n cx a b.)1 a W8W FO p I"w czw C7 A z F c4 Pad Oa �vjia ^ 0.5 TOPSOIL 6" _SM SILTY SAND Tan, moist to wet, medium dense — 5— I 8.0 M H i I SS 12" 27 i 20 BOTTOM OF BORING I I 2 i it i i I THE STRATIFICATION LINES REPRESENT THE APPROXIMATE BOUNDARY LINES BETWEEN SOIL AND ROCK TYPES: IN-SITU,THE TRANSITION MAY BE GRADUAL. WATER LEVEL OBSERVATIONS BORING STARTED 2-18-00 iWL 4 7,7, W.D.I2 7.5' A.B. BORING COMPLETED 2-18-00 WL I ir err acon RIG CME-55 FOREMAN DBC 2 WI- Water Checked 7 Days A.B. APPkovED Dm", JOB II 21005009 LOG OF BORING No. 17 Page 1 of 1 CLIENT ARCHITECT/ENGINEER. P & A Turkey Todd Hodges Design SITE Weld County Roads 49 and 52 PROJECT Kersey, Colorado Proposed 9 Lot Subdivision SAMPLES TESTS O O FF.. >•• toil n co r G� c4 Z Z F w x DESCRIPTION w j Z� ] w ZOW 2Ea �y w E3(el i ', O E'•'O Ff.O Au" OCtc war I I O CI ] Z F c4 c, ,4 Aa ��aa. coax I� 0.5 TOPSOIL 6" _SM 1 SS 18" 10 10 SILTY SAND Brown to tan, moist, medium dense 4.0 2 ST NR WEATHERED CLAYSTONE 3 SS 12" 27 34I Black to red, moist, soft 5 — i g 0 = _ 4 ST 12" 20; 106 3705 1865 I CLAYSTONE/SANDSTONE -.,...-7- - 5 I SS 12" 50 20 i Black to gray, moist i Hard to very hard 10- O15.0 6 SS 9" 50/.8 171 BOTTOM OF BORING 15- I a 0 0 j TE STRATIFICATION LINES REPRESENT THE APPROXIMATE BOUNDARY LINES BETWEEN SOIL AND ROCK TYPES: INSTCU,THE TRANSITION MAY BE GRADUAL. WATER LEVEL OBSERVATIONS BORING STARTED 2-18-00 0 wl- Q 8.9' W.D. ? 7.5' A.B. BORING COMPLETED 1r BORING 2-18-00 WL RIG CME-55 FOREMAN DBC iii WL Water Checked 7 Days A.B. APPROVED DMI, JOB# 21005009 I LOG OF BORING No. 18 Page 1 of I. CLIENT ARCHITECT/ENGINEER P & A Turkey Todd Hodges Design SITE Weld County Roads 49 and 52 PROJECT n . Kersey, Colorado Proposed 9 Lot Subdivision o .a SAMPLES TESTS O --, O E- W w >- x DESCRIPTION En I w t m SP. a. �' at f. o z O 0 a Z F I C coal .4 Ca �cna. ^ 0.5 TOPSOIL 6" _SM SILTY SAND — Brown to tan, moist, medium dense 5.0 — 5— I WEATHERED CLAYSTONE — Gray to tan, moist, soft I I _ I „ 8.0 O — 1 SSi 12"I 28 21 BOTTOM OF BORING - • O p i .- L11 I � 0 THE STRATIFICATION LINES REPRESENT THE APPROXIMATE BOUNDARY LINES BETWEEN SOIL AND ROCK TYPES: IN-SITU,THE TRANSITION MAY BE GRADUAL. WATER LEVEL OBSERVATIONS BORING STARTED 2-18-00 WL h 8.0' W D 7.0' A.B. �rr icon RIG BORING COMPLETED 2-18-00 WL CME-55 FOREMAN DBC WL Water Checked 7 Days A.B. APPROVED Dom, I JOB# 21005009 i LOG OF BORING No. 19 Page 1 of 1 CLIENT ARCHITECT/ENGINEER P & A Turkey Todd Hodges Design L SITE Weld County Roads 49 and 52 PROJECT Kersey, Colorado Proposed 9 Lot Subdivision .a SAMPLES TESTS O O a L F x DESCRIPTION w c v, w zo i LUU cr, U a,O.1 O r}LU ?zai O a Z F C ono Ma, -.ina. I "^ 0.5 TOPSOIL 6" _ CL I SANDY LEAN CLAY Brown to tan, moist, stiff — j — / 6.0 5 — WEATHERED CLAYSTONE _ — 8.0 Gray to tan, moist, soft — 1 SS 112" 15 24 o BOTTOM OF BORING I I O 1 A Y IL I -, THE STRATIFICATION LINES REPRESENT THE APPROXIMATE BOUNDARY LINES BETWEEN SOIL AND ROCK TYPES: IN-SITU,THE TRANSITION MAY BE GRADUAL. WATER LEVEL OBSERVATIONS BORING STARTED 3-27-00 WL 7 8.0I W.D. S 7.0i A.B.' ir BORING COMPLETED 3-27-00 WL RIG CME-55 FOREMAN DBC WL Water Checked 3 Days A.B. APPROVED DM, JOB 21005009 Ia LOG OF BORING No. 20 Page 1 oft 0 CLIENT ARCHITECT/ENGINEER P &A Turkey Todd Hodges Design SITE Weld County Roads 49 and 52 PROJECT Kersey, Colorado Proposed 9 Lot Subdivision SAMPLES TESTS C) F w EL DESCRIPTION w w �• a4w ZO tL� A a U a O . 5 en Am La N W pF,O g aU zFai A A Z F a cnm Aa Avla ^ 0.5 TOPSOIL 6" _SM SILTY SAND — �,WI Brown to tan, moist, medium dense Q _ i 5- 6.0 _ Q 4 WEATHERED CLAYSTONE , / 8.0 Gray to tan, moist, soft - 1 SS 12" 17 I 18 BOTTOM OF BORING I 01, Li; ii THE STRATIFICATION LINES REPRESENT THE APPROXIMATE BOUNDARY LINES BETWEEN SOIL AND ROCK TYPES: IN.SiTU. TRANSnTON MAYBE GRADUAL. WATER LEVEL OBSERVATIONS BORING STARTED 3-27-00 WL U. None W.D. T None A.B. ma 0.1 BORING COMPLETED 3-27-00 lil ' WL ill!rr COfl MG CME-55 FOREMAN DBC WL Water Checked 3 Days A.B. APPROVED DML JOB# 21005009 i 4 I i ill -2 / Water Added i -I s a w ". Ea-- 7 L L la wsi 1 2 N C O N ; ' I I ' L S I D A 4 T I I II 1 N 5 I I 6 7 i 8 1 10 i 0.1 APPLIED PRESSURE.TSF LI Specimen Identification I ' Classification I DD I MC% • 1 7.0 Sandstone/Claystone 105 18 11 i PROJECT Proposed 9 Lot Subdivision-Weld County JOB NO. 21005009 Roads 49 and 52 DATE 5/12/00 CONSOLIDATION TEST Terracon Greeley, Colorado el I 1 3 lilWater Added 2 S W E L L I IN 2 N C O R N S 3 O L I i D A 4 T I O it N 5 I 0 6 I 7 12 8 I ID 0 0.1 I APPLIED PRESSURE.TSF i Specimen Identification IClassification I DDI MC% •� 15 3.0 Silty Sand 112 6 Li PROJECT Proposed 9 Lot Subdivision -Weld County JOB NO. 21005009 Roads 49 and 52 DATE 5/12/00 CONSOLIDATION TEST Terracon Greeley, Colorado 41 Ns I I -g -2 Water Added 7." I E _ L L ------'48 I I 1 '� 1 NH i t ! C NI N N • I S 3 0 L • I - i D A 4 T ! \ I I • 0 I I I I I I 1 N , 6 1 1 I. a 0.1 1 10 APPLIED PRESSURE,TSF I i Specimen Identification I Classification I DD I MC% • 17 7.0 Weathered Claystone 112 16 1 I 3 f I 1 PROJECT Proposed 9 Lot Subdivision-Weld County JOB NO. 21005009 Roads 49 and 52 DATE 5/12/00 x 2 CONSOLIDATION TEST Terracon • il %` Greeley, Colorado x 1] LiINDIVIDUAL SOIL PERCOLATION RATES fl Lot 1 Perc Rate Lot 6 Perc Rate 56 70 62 29 a 45 45 53 62 62 42 a45 25 Lot 2 28 Lot 7 80 _ f 38 100 22 106 17 160 a 44 145 12 115 Lot 3 50 Lot 8 37 LI 62 53 69 49 57 57 49 45 60 45 0 Lot 4 180 Lot 9 58 140 49 35 65 60 53 150 57 90 60 Lot 5 41 Lot A 95 ul 74 .57 55 105 • 53 55 Li:, 71 120 60 60 Lot B 15 �* 25 18 rol 60 45 53 0 0 0 DRIWNG AND EXPLORATION 0 DRIWNG & SAMPLING SYMBOLS: RS : Ring Sampler-2.42" I.D. 0 SS : Split Spoon - 1_" I.D., 2" O.D., unless otherwise noted PS : Piston Sample ST : Thin-Walled Tube— 2-1/2" I.D., unless otherwise noted WS : Wash Sample PA : Power Auger FT : Fish Tail Bit HA : Hand Auger RB : Rock Bit 0 DB : Diamond Bit = 4", NI, B BS : Bulk Sample AS : Auger Sample PM : Pressure Meter HS : Hollow Stem Auger DC : Dutch Cone WB : Wash Bore U Penetration Test: Blows per foot of a 140 pound hammer falling 30 inches on a 2-inch O.D. split spoon, except where noted. U . WATER LEVEL MEASUREMENT SYMBOLS: WS : While Sampling ' WL : Water Level WCI : Wet Cave in WD : While Drilling DCI : Dry Cave in BCR: Before Casing Removal UAB : After Boring ACR: After Casting Removal Water levels indicated on the boring logs are the levels measured in the borings at the time indicated. In pervious soils, the indicated levels may reflect the location of groundwater. In low permeability soils, the accurate 0 determination of groundwater levels is not possible with only short term observations. • DESCRIPTIVE SOIL CLASSIFICATION: Soil Classification is based on the Unified Soil Classification system and the ASTM Designations D-2487 and D-2488. 0 Coarse Grained Soils have more than 50% of their dry weight retained on a #200 sieve; they are described as: boulders, cobbles, gravel or sand. Fine Grained Soils have less than 50% of their dry weight retained on a #200 sieve; they are described as: clays, if they are plastic, and silts if they are slightly plastic or non-plastic. Major constituents may be added as modifiers and minor constituents may be added according to the relative proportions based on grain size. In addition to gradation, coarse grained soils are defined on the basis of their relative in-place density and fine grained soils on the basis of their consistency. Example: Lean clay with sand, trace gravel, stiff (CL); silty sand, trace gravel, medium dense (SM). p CONSISTENCY OF FINE-GRAINED SOILS: RELATIVE DENSITY OF Unconfined Compressive COARSE-GRAINED SOILS: Strength, Qu, psf Consistency N-Blows/ft. Relative Density < 500 Very Soft 0-3 Very Loose 500 - 1,000 Soft 4-9 Loose 1,001 -2,000 Medium 10-29 Medium Dense U . 2,001 - 4,000 Stiff 30-49 Dense 4,001 -8,000 Very Stiff 50-80 Very Dense 8,001 -16,000 Very Hard 80+ Extremely Dense U RELATIVE PROPORTIONS OF SAND AND GRAVEL GRAIN SIZE TERMINOLOGY Descriptive Term(s) Major Component (of Components Also Percent of of Sample Size Range Present in Sample) Dry Weight Boulders Over 12 in. (300mm) Trace < 15 Cobbles 12 in. to 3 in. With 15 -29 (300mm to 75mm) ' Modifier > Gravel 3 in. to#4 sieve 30 (75mm to 4.75mm) Sand #4 to#200 sieve fl RELATIVE PROPORTIONS OF FINES (4.75mmto .075mm) Descriptive Term(s) Silt or Clay Passing #200 Sieve (of Components Also Percent of (0.075mm) Present in Sample) Dry Weight LI Trace < 5 With 5 - 12 Modifier > 12 . lrerracon 0 GENERAL NOTES 1 U Sedimentary Rock Classification I DESCRIPTIVE ROCK CLASSIFICATION:LI silt and sand sized particles.The most Sedimentary rocks are composed of cemented clay, common minerals are clay, quartz and calcite. Rock composed primarily of calcite is called limestone; rock of sand size grains is called sandstone,and rock of clay and silt size grains LI is called mudstone or claystone,siltstone,or shale.Modifiers such as shaly,sandy,dolomitic, calcareous,carbonaceous,etc.are used to describe various constituents.Examples: sandy shale; calcareous sandstone. LIMESTONE Light to dark colored, crystalline to fine-grained texture,composed of CaCo3, reacts readily : U with FICI. DOLOMITE Light to dark colored, crystalline to fine-grained texture, composed of CaMg(CO ):, harder than limestone, reacts with HCI when powdered. CHERT Light to dark colored,very fine-grained texture, composed of micro-crystalline quartz(Si02), I{� brittle, breaks into angular fragments, will scratch glass. SHALE Very fine-grained texture, composed of consolidated silt or clay, bedded in thin layers.The unlaminated equivalent is frequently referred to as siltstone, claystone or mudstone. 0 SANDSTONE Usually light colored,coarse to fine texture,composed of cemented sand size grains of quartz, feldspar,etc.Cement usually is silica but may be such minerals as calcite,iron-oxide,or some other carbonate. CONGLOMERATE Rounded rock fragments of variable mineralogy varying in size from near sand to boulder size but usually pebble to cobble size(1/2 inch to 6 inches).Cemented together with various cemen- ting agents. Breccia is similar but composed of angular, fractured rock particles cemented together. 4 PHYSICAL PROPERTIES: LI DEGREE OF WEATHERING BEDDING AND JOINT CHARACTERISTICS Slight Slight decomposition of parent Bed Thickness Joint Spacing Dimensions material on joints. May be color Very Thick Very Wide >10' Thick Wide 3' - 10' change.LI Medium Moderately Close 1' - 3' Moderate Some decomposition and color Thin Close 1' - 1' change throughout. Very Thin Very Close 4" - 2" High Rock highly decomposed,may be ex- Laminated .1" - .4" tremely broken. Bedding Plane A plane dividing sedimentary rocks of the same or different lithology. HARDNESS AND DEGREE OF CEMENTATION Joint Fracture in rock, generally more or less vertical or transverse to bedding,— Limestone and Dolomite: along which no appreciable move- Hard Difficult to scratch with knife. ment has occurred. Generally applies to bedding plane Moderately Can be scratched easily wt with g knife, Seam PP — Hard cannot be scratched with fingernail. with an unspecified degree of Soft Can be scratched with fingernail. weathering. Shale, Siltstone and Claystone SOLUTION AND VOID CONDITIONS Hard Can be scratched easily with knife, Contains no voids. cannot be scratched with fingernail. Solid Vuggy (Pitted) Rock having small solution pits or Moderately Hard Can be scratched with fingernail. cavities up to 1/2 inch diameter, fre- quently with a mineral lining. _. Soft Can be easily dented but not molded Porous Containing numerous voids,pores,or with fingers. other openings, which may or may not interconnect. Sandstone and Conglomerate _) Well Capable of scratching a knife blade. Cavernous Containing cavities or caverns,some- times quite large. __! Cemented Cemented Can be scratched with knife. I4 i Poorly Can be broken apart easily with Cemented fingers. 1lerracon Farm 110-6-85 'is UNIFIED SOIL CLASSIFICATION SYSTEM Soil Classification cli Criteria for Assigning Group Symbols and Group Names Using Laboratory Test? Group Symbol Group Names Coarse-Grained Soils Gravels Clean Gravels Cu ≥ 4 and 1 ≤ Cc ≤ 3e GW Well-graded gravels More than 50% retained on More than 50% of coarse Less than 5% fines° Cu < 4 and/or 1 > Cc > 3s GP Poorly graded gravels No.200 sieve fraction retained on No.4 sieve Fines classify as ML or MH GM Silty gravels E1 H Gravels with Fines More than 12% fines° Fines classify as CL or CH GC Clayey gravels,6,H Sands Clean Sands Cu ≥ 6 and 1 ≤ Cc ≤ 3s SW Well-graded sand' 50fror more of coarse Less than 5% finess Cu < 6 and/or 1> Cc > 3s SP Poorly graded sand fraction passes No.4 sieve Fines classify as ML or MH SM Silty sands's,' I Sands with Fines More than 12%lines° Fines classify as CL or CH SC Clayey sands,H•I Fine-Grained Soils Silts and Clays Inorganic PI > 7 and plots on or above"A"line CL Lean clays.4 M 50% or more passes the Liquid limit less than 50 PI < 4 or plots below"A" lined ML Silts.4 M No.200 sieve Liquid limit —oven dried Organic clays,L. M,N organic < 0.75 OL Liquid limit —not dried Organic silt„.L,M,0 Silts and Clays inorganic PI plots on or above"A"line CH Fat clays.4 M Liquid limit 50 or more PI plots below"A" line MH Elastic silts,1,14 M Liquid limit—oven dried Organic clays'4 M,P organic < 0.75 OH Liquid limit— not dried Organic silts.L,M,6 0 Highly organic soils , Primarily organic matter,dark in color,and organic odor PT Peat ABased on the material passing the 3-in. s (D30)2 alf soil contains 15 to 29% plus No.200,add (75-mm)sieve. Cu = l),/D10 = "with sand" or"with gravel",whichever is 0 Elf field sample contained cobbles or F DD, predominant. boulders,or both,add "with cobbles or If soil contains≥ 15% sand,add"with sand"to 1If soil contains ≥ 30% plus.No.200 group name. predominantly sand,add"sandy"to group boulders,or both"to group name. o P °Gravels with 5 to 12% fines require dual If fines classify as CL- L, use dual symbol GC- name. GM,or SC-SM. MY soil contains ≥ 30% plus No.200, 0 GW-GM well-graded gravel with silt symbols: "If fines are organic,add "with organic fines"to 9 predominantly gravel,add "gravelly"to group GW-GC well-graded gravel with clay group name. name. GP-GM poorly graded gravel with silt 'If soil contains ≥ 15% gravel,add"with gravel" to Hpl ≥ 4 and plots on or above"A"line: GP-GC poorly graded gravel with clay group name. 0PI < 4 or plots below"A"line. °Sands with 5 to 12% fines require dual dIf Atterberg limits plot In shaded area,soil is a CL- PI-6 plots on or above"A"line. symbols: ML,silty clay. SW-SM well graded sand with silt °PI plots below"A"line. SW-SC well-graded sand with clay SP-SM poorly graded sand with silt SP-SC poorly graded sand with clay 60 I I I I / For classification of line-grained soils // and fine-grained fraction of coarse- 50 _grained soils // Equation of "A"-line �V"/ \�F. - Horizontal at PI = 4 to LL = 25.5. \, EL then PI = 0.73(LL-20) °J/ O� eP- 40 -Equation of "U"-line / de / s a X Vertical at LL = 16 to PI = 7, // O Z then PI = 0.9(LL-8) >-- 30 / H- / / ~A pp / EL. / / P O>' / _MH oR OH 10 / 7 _ / CL=-;ML' / ML OR OL 4 I I 0 0 10 16 20 30 40 50 60 70 80 90 100 110 LIQUID LIMIT (LL) 0 s '1lerracon Form 111-6.65 Hello