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HomeMy WebLinkAboutDrainage Reports - 05/10/2002Anal Approved Rep6i � ' D �j�r@ s ro aZ APR 3 0 2002 Drainage Design Considerations for Liberty Common School Fort Collins, Colorado April 5, 2002 DMW Davis, Miller & Wohrnrade Civil Engineers, Inc. 1455 W. 29th Street, Loveland, Colorado 80555 Fhone1*970-461-2661, Fax: 720-489-2905 I 1 1 1 1 1 1 1 1 1 1 1 1 1 1 Drainage Design Considerations for Liberty Common School Fort Collins, Colorado April 5, 2002 Prepared for: Liberty Common School 1725 Sharp Point Drive Fort Collins, Colorado 80525 Prepared by: DMW Dav15, Miller 4� Wohnrade Civil Engineers, Inc. 1435 W. 29`h Street Loveland, Colorado 80538 Phone: (970)461-2661 , Fax: (970)461-2665 Project Number: 0203.00-LC5 VIM Davis, Miller Wohnrade Owl En sneers, /nC. 1435 W. 29" Street, Loveland, Colorado 80538 9 Phone: 970-46 I -2661 , Pax: 970-46 I -2665 April 5, 2002 City of Fort Collins Stormwater Utility 700 Wood Street Fort Collins, Colorado 80521 RE: Liberty Common School Fort Collins, Colorado Project Number: 0203.00-LCS Dear Staff: Davis, Miller & Wohnrade Civil Engineers, Inc. (DMW) is pleased to re -submit this report for Liberty Common School for a Site Plan Advisory Review. This report was prepared in compliance with technical criteria set forth in the City of Fort Collins Storm Drainaae Desian Criteria and Construction Standards manual. If you should have any questions or comments as you review this report, please feel free to contact me at your convenience. Sincerely, Davis, Miller & Mary B. Wohni Project Manage,. eers, Inc. ' Drainage Design Considerations for ' Liberty Common School 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 1.4 Site Reconnaissance....................................................................... 1 II SITE LOCATION AND DESCRIPTION 2.1 Site Location.................................................................................... 1 2.2 Floodplain.........................................:.....................................:........ 1 2.3 Site Description............................................................................... 2 ' III PRE -DEVELOPMENT CONDITIONS 3.1 Major Drainage Basin...................................................................... 2 3.2 Pre -development Drainage Basins .................................................. 2 IV POST -DEVELOPMENT CONDITIONS 4.1 Proposed Site Improvements........................................................... 2 N 4.2 Post -development Drainage Patterns .............................................. 3 4.3 Post -development Drainage Basins ................................................ 3 V DESIGN CONSIDERATIONS 5.1 Design References.......................................................................... 3 5.2 Hydrologic Criteria............................................................................ 3 5.3 Hydraulic Criteria............................................................................ 3 5.4 Detention Requirements.................................................................. 4 5.5 Street Capacity ................................................................................ 4 VI EROSION CONTROL 6.1 Erosion Control Plan........................................................................ 4 VII WATER QUALITY 7.1 Extended Detention......................................................................... 4 Vill CONCLUSIONS 8.1 Compliance with Standards............................................................. 4 8.2 Easements....................................................................................... 4 REFERENCES........................................................................................... 5 Vicinity Map - Liberty Common School OF Old ME= A- Q 3 �t. 2 A za A: PR LISPLCT q�I O 9 x Legend o > `725 .• HARP aQi`rlwldftl Parcels .�� R a+lroads y .*' 4 Street Centerlines River. St rearm. and Ditches _ ■ Lakes and Waler Bodies l City LJmts ❑ N:hn C. i _ [CRAKE RD� v NapaKaLed with ArclNS-Copyrig hi {CJ 19B2-2001 ESRI Inc. � Q Drainage Design Considerations for Liberty Common School EXHIBITS Exhibit 1 City of Fort Collins GIS Floodplain Mapping Exhibit 2 Pre -Development Drainage Plan Exhibit 3 Post -Development Drainage Plan APPENDICES Appendix A: Excerpts from the 1988 Vipont Drainage Report Appendix B: FIRM Floodplain Mapping Appendix C: Rational Method Runoff Calculations Appendix D: Street Capacity Calculations Appendix E: Extended Detention Calculations Appendix F: Erosion Control Calculations DRAWINGS Drawing 1 Sheet 8 of 8, from the Storm Drainage Report for Vipont Manufacturing Facility, Stewart & Associates, August 1, 1988. I I 11 C r I I I Drainage Design Considerations for Liberty Common School Fort Collins, Colorado April 5, 2002 I. INTRODUCTION 1.1 Objective To provide documentation of a drainage evaluation for both pre and post - development conditions for the Liberty Common School site. Specific objectives as part of this study are: 1. To address the street capacity of Sharp Point Drive, at a design point located downstream of the project site, for both pre and post -development conditions; 2. To provide the design of an extended detention, water quality facility; 3. To consider any possible adverse effects downstream of the development due to developed stormwater. 1.2 Project History and Previous Studies The Liberty Common School site was formerly the Vipont manufacturing facility. A drainage report (Reference 1 and Appendix A) was prepared for the Vipont development in 1988 by Stewart & Associates. 1.3 Mapping and Surveying Aerial topographic mapping of the site at a two (2) foot contour interval was obtained from the City of Fort Collins Geologic Information System department and is dated April, 1999. 1.4 Site Reconnaissance A site visit was conducted on February 11, 2002 by the project engineer. Based on the topographic mapping, existing drainage basins and land use were confirmed as well as existing structures. II. SITE LOCATION AND DESCRIPTION 2.1 Site Location The site is located in the NE Quarter of Section 20, Township 7 North, Range 68 West of the 6th Principal Meridian in Fort Collins, Colorado. The project is bounded by Sharp Point Drive on the east and East Prospect Road on the north. (See Vicinity Map). 2.2 Floodplain Based on the City of Fort Collins GIS information, the Liberty Common School is located outside of the regulatory floodplain of the Cache La Poudre River (See Exhibit 1.) The Flood Insurance Rate Map (FIRM) has also been referenced which confirms that the site is located outside of the Special Flood Hazard Area (See Appendix B.) ' Drainage Design Considerations Davis, Miller & Wohnrade Civil Engineers, Inc. Liberty Common School April 5`2002 2.3 Site Description Liberty Common School is located on Lot 8 of Prospect Park East P.U.D. and, Lots 1 , 2, 3, 6 and part of Lot 23 of Prospect Industrial Park. The site is approximately 7.76 acres and is partially developed with an existing building, driveway, parking lot and playground (See Exhibit 2). Lots 3 and 6 remain undeveloped at this time and may be used in the future as playing fields. III. PREDEVELOPMENT CONDITIONS 3.1 Major Drainage Basin The site is located in the Poudre River drainage basin and, partially in the Spring ' Creek drainage basin according to the City of Fort Collins stormwater basin map. 3.2 Pre -Development Drainage Basins ' The pre -developed site has been divided into three distinct drainage basins. The basin boundaries delineated by DMW are consistent with the boundaries on Sheet 8 of 8 from the 1988 report by Stewart (See Drawing 1). ' Basin H1 (4.5 acres) drains overland from northwest to southeast at a slope of 1.20% to Sharp Point Drive and March Court. Basin H1 includes both on and off -site areas draining to Design Point H1. Basin H2 (1.1 acres) drains to an existing four (4) foot curb inlet located west of the existing school. Stormwater is conveyed from the inlet thru a storm sewer to an existing pond located north of the project site. ' The roof of the existing building makes up the majority of Basin H3. Runoff from the roof is directed to.the north to the existing pond mentioned previously. ' Stormwater runoff from all three basins is eventually routed to the Prospect Ponds Natural Area which is located to the east of the site. 1 IV. POSTDEVELOPMENT CONDITIONS ' 4.1 Proposed Site Improvements Planned development for the Liberty Common School site includes the addition of a gymnasium. The area of the gymnasium roof is 18,918 sf (0.43 acres.) The ' area to be occupied by the proposed gymnasium is currently covered with asphalt and concrete sidewalks and, a gravel playground. The overall imperviousness of the site will be increased due to the gymnasium addition. Page 2 ' Drainage Design Considerations Davis, Miller & Wohnrade Civil Engineers, Inc. Liberty Common School April 5, 2002 ' 4.2 Post -development Drainage Patterns The overall drainage pattern of the site will remain unchanged from pre to post - development conditions. Stormwater runoff from Basin 1 will drain overland to ' Sharp Point Drive and March Court as it has done historically. Basin 2 will continue to drain to the existing curb inlet and, Basin 3 will also follow the historic drainage pattern. 4.3 Post -development Drainage Basins The area of Basin 1_(4.6 acres) increased slightly compared to historic Basin H1 ' (4.5 acres.) The peak 2 and 100-year discharges at Design Point 1 are 2.9 and 13.0 cfs respectively (See Exhibit 3.) The area of Basin 2 (1.0 acres) has been ' reduced slightly compared to historic Basin H2 (1.1 acres.) Basin H3 will remain unchanged. ' V. DESIGN CONSIDERATIONS 5.1 Design References ' Drainage design criteria specified in both the City of Fort Collins Storm Drainage Design Criteria Manual.(SDDCM) and Storm Drainage Criteria Manual, Volume 3, by the Urban Drainage and Flood Control District have been referenced for this study. 5.2 Hydrologic Criteria ' The Rational Method has been used to estimate peak stormwater runoff from the developed site. The initial 2 and 10-year and, major 100-year design storms have been used in the evaluation of pre and post -development drainage ' conditions (See Appendix C.) Rainfall intensity data for the pre -development condition has been taken from ' the old intensity curves (Figure 3-1 of the SDDCM.) Rainfall intensity data for post -development conditions has been taken from the new rainfall intensity data ( Figure 3-1b.) The time of concentration to Design Point 1 remained the same ' for both pre and post -development conditions. 5.3 Hydraulic Criteria The computer program "Flowmaster" has been used to analyze the capacity of the proposed PVC pipe which conveys stormwater from the extended detention ' facility to March Court. 1 ' Page 3 ' Drainage Design Considerations Liberty Common School ' April 5, 2002. Davis, Miller & Wohnrade Civil Engineers, Inc. ' 5.4 Detention Requirements Detention is not a requirement for the proposed development due to the proximity of the site to the Cache La Poudre River. 5.5 Street Capacity The street capacity of Sharp Point Drive has been determined based on design drawings for Prospect Industrial Park. The capacity of the street is based on the 2-year design storm and is estimated to be roughly 3.3 cfs. The 2-year peak discharge at Design Point 1, based on post -development conditions, is 2.9 cfs. The street capacity at Design Point 1 then, has not been exceeded. Appendix D contains calculations in support of this analysis. VI. EROSION CONTROL 6.1 Erosion Control Plan The erosion control plan presented here is intended to control rainfall erosion. The Erosion Control Reference Manual for Construction Sites (ECRM), City of Fort Collins, has been referenced for this erosion control plan. The proposed rainfall erosion control plan during construction will consist of temporary structural erosion control measures. A gravel inlet filter will be placed at the existing area inlet located west of the existing school. Temporary sediment control consisting of silt fencing will surround the area of the proposed gymnasium addition. VII. WATER QUALITY 7.1 Extended Detention Extended detention will not be provided for the proposed gymnasium addition. A variance is requested for this requirement. ' VIII. CONCLUSIONS 8.1 Compliance with Standards ' All drainage analyses have been performed according to the City of Fort Collins Storm Drainage Design Criteria Manual (SDDCM) and, the Urban Drainage and Flood Control District's Drainage Criteria Manual. 8.2 Easements No easements are required for the proposed project. ' Page 4 Drainage Design Considerations Davis, Miller & Wohnrade Civil Engineers, Inc. Liberty Common School ' April 5, 2002 1 ' REFERENCES 1.) Storm Drainage Report for Vipont Manufacturing Facility, Stewart & Associates, August 1, 1988. 2.) Storm Drainage Design Criteria and Construction Standards, City of Fort Collins, Colorado, May, 1984. ' 3.) Drainage Criteria Manual, Volume 3, Urban Drainage and Flood Control District, Wright -McLaughlin Engineers, Denver, Colorado, March, 1969. ' Page 5 I 1 LJ I Exhibits 11 11 No Text EPv_ 16 0 ®s0 AERIAL MAPPING PROVIDED BY THE CITY OF FORT COLLINS GEOGRAPHIC INFORMATION SYSTEM, MAP NO.'S 87201 AND 87202. (APRIL, 1999) LEGEND: JIB w STORY SEWER EITHRNO STORY SEWER Y IMET PROPOSfO STORY SEWER OR CULVERT PROPOSED STORY SEWER OR CIKV WIiH 'INLET - W20 DaSnNO CONMR 20 PROPOSED CONTOUR _ _ PRO.IECf SUUNDWN ORWNNR: SISIN D NQNIV MSN WNEI. 5D Nifi1 IN ACRE Al OESICN PONE z O o Z zz a z co �UCL zw 2 M G U Xaz } LU O E >o J n w� A� P+iiri o� w i�:r elm Pwlwl ra: mzum md: � Nz m.b,ee ar .eR WNw•e fIr �1 9MWE. 0 FLti A IBERTY COMMON e SCHOOL ps ' L O H o Z O OZ 0 UQ N cr) ~WW m (� O X09 F W_IQ OC m > W� J 0 F- Ezof-,�-- AERIAL MAPPING PROVIDED 9Y THE CITY OF FOR' COLLINS GEOGRAPHIC INFORMATION SYSTEM, MAP NO.'s 87201 AND 87202. (APRIL. 1999) ILEGEND: ExsnRc sroRY sE>,v+ _ n E Ws S DRY SEaEER R w 7 aRDPOSED STORY SEWFA OR CULVERT ��....,�., e PROPOSED SRMY SE q OR CULVERT m� Rltl 5D20 EJ 61W OORIOUR 2p 'ROPOSED MR R zjj oRWEM 3ouuoun a: �...m a ORVIWiE 3ASiN 30UROYt+ /mNl 5ww i� 3LSM IASEL � m 1 Dr'•.�• ey i0 AR A R •GRE RrInM 9/ 7 OESCR POW! un 1 7�1•h ilto I 1 1 1 I Appendix A I vti �O STEWARr&ASSOCIATES Consuffing Engineers and Surveyors I INovember 2, 1990. Mt. Susan Duba Hayes, P.E. Storm Water Utility ' City of Fort Collins P 0 Box 580 Fort Collins, CO 80522 ' RE: Proposed new paving on the Vipont Manufacturing Facility site. Dear Susan: ' In August of 1988 a drainage report and plan was submitted for the Vipont Manufacturing Facility located on lot 8 in Prospect Park East and on lots 1, 2 and part of 23 in Prospect Industrial Park. The runoff calculations presented in that report are based on a fully developed site. The additional storm water runoff quantity which will be caused by the proposed parking lot paving is included in the 1988 quantity ' calculations. I am attaching a copy of that 1988 report along with a copy of the plan showing the proposed paving in red. Please call if you need further information. Sincerely, Phillip I. Robinson, P.E. & L.S. Vice President %%o;YfiO�f.,,,�� 1 kk �y�•�� .G�y7EhFO.� ` ; e '-. enclosures _ t 5 p 2 _*. - 4 -- leol' f .•;J.` James H. Stewart ' and Associates, Inc. 214 N. Howes Street P.O. Box 429 . t e/zlee � o 1 1 STORM DRAINAGE REPORT ' FOR VIPONT MANUFACTURING FACILITY The proposed Vipont Pharmaceuticals building is located on Lot 8 of ' Prospect Park East and on Lots 1. 2 and part of 23 Prospect Industrial Park. The site is in Flood Zone C per the FIRM flood map. Sheet 3 of this report shows a Xerox copy of the flood zone map with the lots overlayed. ' This site is located in a previously developed area. The streets and major drainage ways were constructed in 1984-85. No onsite storm drainage ' detention has been required for development in this area since the site drains directly into the Cache la Poudre River. This site consists of 7.91 acres. 4.79 acres drains to an existing pond (not a detention pond) located at the northeast corner of the site. and 3.12 acres of the site drains to Sharp Point Drive. The permanent pond at the northeast corner of the site is located on the west side of Sharp Point Drive. The pond overflows under Sharp Point Drive through 3-24 inch pipes as shown on attached sheet 3 of 12 of Prospect Park East. The 3 pipes drain into an old gravel pit. This is shown on the attached sheet 3 of 12 of the Prospect Park East P.U.D. plans. The old gravel pit is on the Anderson ' property, and there is an agreement with the Andersons to take the drainage. The 3-24 inch pipes will carry approximately 60 c.f.s. when running full. The flow line of the pipes is 90.0. and the overflow elevation of Sharp Point Drive is 95.0. The capacity of the pipes at overflow is 101.4 c.f.s. The previous drainage reports do not give a total flow into the pond, but there is approximately 80 acres draining to the pond. The 80 acres will produce 104 c.f.s. run-off during the ' 10 year storm and 297 c.f.s. during the 100 year storm. From these figures, it appears the pond out -flow may just overtop Sharp Point Drive during the 10 year storm. When the pond elevation is at elevation 95.0. the storm pipe back into the site will be full, and the water will back into the dock area to a depth of 1.0 feet. This dock area, not a parking area, may pond to a depth.of 3.2 feet before it overflows into the swale to the north. This depth is more than the allowable for parking areas, but the outlet is not restricted and will carry the 100 year storm, and the area is a loading dock, most of which are more than 1.5 feet deep. The drainage to Sharp Point Drive from the southerly 3.12 acres drains to the south along the west side of Sharp Point Drive, and then crosses to the east in an existing concrete pan. This pan is located 200 feet south of the Vipont site. The pan drains into a pond on property of the City of Fort Collins. The attached sheet 3 of 8 of the Prospect Industrial Park plans shows the cross pan. Flows to this, pan may cause Sharp Point Drive to overtop to the east, but this should cause no problems since the City ponds are all along the east side of Sharp Point Drive. These ponds would overflow directly into the Cache la Poudre River. I The existing drain ditch from Midpoint Drive to the pond area is to be ' partially located due to a replat in Prospect Park East. This replat was done in 1984, but the drain ditch was not relocated at that time. The details of this swale are shown on the attached sheet 11 of 12 of Prospect Park East plans. There is some possible offsite flow from Lot 22 and the remainder of Lot 23 of Prospect Industrial Park. This area is 1.65 acres and presently ' undeveloped. The offsite flow will go into the dock area (Area No.2) shown on sheet 8 of 8 of this report. ' The storm drainage plan for the Vipont Manufacturing Facility conforms to the previously approved drainage plans and reports for both Prospect Park East and Prospect Industrial Park. .' This report prepared by L22�1 hl� ` Phillip I. Robinson; P.E. & L.S. G\STEKFO.vy����� 4502 : -- "* & . l00*0 uun 1 I F I 1 i No Text STEWART&AR MATES iCOMPUTATIONS Consult" EnSlnem and &xveyors 7 . 214 N. Howes St. Ft. Collins, CO 80521 003) 482-9331 By:, PJK Date a Client: To n!2 e TZ-gt'c� 11,440ee Sheet No. --S—of :hkdBy: —Date —Project:-I/ijaonf- in Prag4ec� /nd. T>ctHf I . I rn t� c vo, I mIrAls. a--- , -1 1 IIIIWIIM J --Z LO 01;L Y- --- plp k Lfr- lcc- ; c lY A r e cl/ 00 COMPUTATIONS STEWART$8S_ JOATES. ��. `::'." '„ . '.. ,_ ' : ' '. • . 214 NN. Howes St. Ft. Collins, CO 80521 (303) 482-9331 DD'' By•Date % Client: 7V ►1 Je— Re I. c 1-1 M c+!5Ce Sheet No. 50� of ChkdBy: Date Project: 'Subject A/r>y4 in Prosped bid, 1'Gr!r `5fo r-ri Drn i nao e �.._ i ' : I I TC-1 _ 4.6.. _ I 1. i N„ J�LI i I i I _ � I ............. .... ... ii : I .......... I I COMPUTATIONS STEWART&AS. JGATES. Consult" EMIm s and surveyors . - �. 214 N. Howes St. Ft. Collins, CO 80521 (303) 482-9331 ' By: p/R Date 3 i Client: T m!!• e, Rti c A MAae_Sheet No. 7 of Chkd By: Date Project: V f r% �- u� sae c7' 1^ J• lark Subject .S•i'ot-..n Dra i to av s .O..-. i I i I e n I I n1i E- -. -- - h Wl e .. e --- - -- P1 - -- - . _ _.- .. e i r' 9:0. a' �I. _ _.Pu- i 1 i q-,0 riv. 0.---C -° -.._ 3- .15 0 1 , -3 -_ z ¢. i ._.. - - _ C 80 - 0-r i ! - 3 _ 1.1 .• oil i z� :ter i �I �F 1. = S dr O f i I � i J I 71 1 E 1 I Fl 1 1 1 I 1 Appendix B I LCS: 0203.00 Date: 02/27/02 Scale: N.T.S. Demgned ii: �: 1� NATIONAL FLOOD INSURANCE PROGRAM m1i I 1111i FLOOD INSURANCE RATE MAP CiTY OF FORT COLLINS, COLORADO LARIMER COUNTY (SEE MAP INDEX FOR PANELS NOT PRINTED) COMMUNITY -PANEL NUMBER 080102.0012 C MAP REVISED: MARCH 18, 1996 Federal Emergency Management At!encv LIBERTY COMMON SCHOOL FIRM PANEL TITLE BOX D"IS, MILLER & WOHNRADE_ CIVIL ENGINEERS, INC. 1435 West 2M Street, Loveland, Waned., 805M Phone: (970)461-2661. I= (970)461-2665 L Project: tom:0203.00 Date: 02/27/02 Scale: N.T.S. Designed By. maw ZONE ;- ZO jyE A E .ZONE AE 489 AD 4892 ZONE A� AC F I i'M Boxeluer Ditc!" Diversion Dam FLOODING EFFECTS FROM, CACHE LA POUDRE LIBERTY COMMON SCHOOL FIRM FLOODPLAIN MAPPING F'8u Levee ZONE A D"IS, MILLER & WOHNRADE CIVIL ENGINEERS, INC. 1435 West 29th Street Loveland, Colorado, 80538 Phan.: (970)461-2661. F= (970)461-2665 Shee2 t 2 Shoots E 1 i 11 1 i 1 1 1 1 L 1 1 1 I G I 1 _ Pre -Development Condition Composite Runoff Coefficient Calculations Character of Surface Runoff Project: Liberty Common School Coefficient Calculations By: M. Wohnrade Sheets, Parking Lots, Drives: Date: February 23, 2002 Paved ........................... 0.95 Gravel........................... 0.50 Roofs........................... 0.95 Lawns, Sandy Soil < 2% 0.10 Lawns, Heavy Soil < 2•/ 0.20 Runoff Coefficients are taken from the City of Fort Collins Storm Drainage Design Criteria Manual, Table 3-3 Basin Basin Area of Area of Area of Parking Area of Roofs Area of Lawn and Weighted ID Area Pared Gravel Lots, Dries, Landscape, Runoff Streets & Streets Walks Heavy Soil Coefficient (Acres) Walk (Acres) (Acres) (Acres) (Acres) (Acres) H1 4.5 0.80 0.00 0.78 0.08 2.84 0.48 -`Post Development Cond�bon ,T , Composite RunofifCoetricient•Calculadons ^ t° Character of Surface Runoff Project: Liberty Common School Coefficient Calculations By. M. Wohnrade Sheets, Parking Lots, Drives: Date: February 23, 2002 Paved ........................... 0.95 Gravel ........................... 0.50 _ Roofs ........................... 0.95 Lawns, Sandy Soil < 2•/ 0.10 Lawns, Heavy Soil < 2% 0.20 Runoff Coefficients are taken from the City of Fort Collins Storm Drainage Design Criteria Manual, Table 3-3 Basin Basin Area of Area of Area of Parking Area of Roofs Area of Lawn and Weighted ID Area Paved Gravel Lots, Drives, Landscape, Runoff Streets Streets Walks Heavy Soil Coefficient (Acres) (Acres) (Acres) (Acres) (Ace) (Acres) 1 4.60 0.80 0.00 0.57 0.51 2.72 0.51 F:\DM VAProjects\Lcs\KnffCoeff. wpd . e 0 7� �� M g c m . _ o g . § _ CIA . E q =' �0 cj g ` m % t U- E - . G: 2 \®\ § § q d � 0 \f � A& cn § ` O ME °! E co U � ! m O c - � � [ a _ � ME @ _ E t� c K .. _ - . � .0 2 . - Um / ( � § W 22 m @ A £ _ �v ° 0U. 0 E aEE © ® ` 7 f a o 24)0 - 00 F �k 4) ��� 3.R � 2 � @ 02co 'oZ 3 A k § 1 5 i� $ a$% QOR o�� �5>� - /�)� �9 Jz L O „ U O .0 o u �- N vi 0 vi L a � U CU) C N J` mz cli E c%. = p U N m CD N M y W L m O O O O J U U- 3 Qi la-0) ° v o>a o 0 0 _V o => mW U� no 0 0 0 N O N L J t N +0 cu O O O = U Q N 0 U � U 2 m N m m> 0 a N •� c O j U ca n n n O J S O O O Of .X IA 17 n l"I A l7 C J — CL O 0 U c ~ E f N h H m N L V N > IL = 0 C CN C F 9 O V) � C N VI C a)L9 0 0 6J O> r m m m . WI LLL C m H y J N N N O w O� :p C O mU C M A U o c o C U O N U O O N C m 0 ,� 7 Q 0 .- rn— V UQ a)N 11. LL O E U E II v m i= c00 c o 0 —_� C J C C 0 •— O W U Y O a N A v u O m O m O m 3U IL c m u <� e c v U o m ca " 0 �ti> EXv�.w s o CIS `%CO + E E E co 0 J H Z C 0 0 0 .= > II 7 IIII° fU) +r a)f6 w "o c Cc° UGH C9F-F->�' oa f �3 G � .50 r .20 .10 m a o m 06 m m 04 Qom Q� .02 .01 .005 1 2 4 6 10 20 Average velocity (ftlsec) EQUATION FOR FIGURE 3-1: PAVED: V=16.1345(s)D.s UNPAVED: V=20.3282(s)0.5 (210-N'1-TR-M, Seruua Ed., Jum istxs) s= slope in ft/ft 22.00 'CWS Dote: 02/05/02 Stake: NA � �gned FIGURE 3-1 AVERAGE VELOCITIES FOR SHALLOW CONCENTRATED FLOW ' D"IS, MILLER & WOHNR"E CIVIL ENGINEERS, INC. 1435 W d 29th Stroet, Lmland, CeIm da, 60536 `hT Phone: (970)161-2661, Fes (970)461-2665 Sheet Sheets No Text City of Fort Collins Rainfall Intensity -Duration -Frequency Table for using the Rational Method (31 minutes-. 60 minutes) Figure 3-1 b Duration (minutes) 2-year Intensity in/hr 10-year Intensity in/hr 100-year Intensity in/hr 31.00 1.27 2.16 4.42 32.00 1.24 2.12 4.33 33.00 1.22 2.08 4.24 34.00 1.19 2.04 4.16 35.00 1.17 2.00 4.08 36.00 1.15 1.96 4.01 37.00 1.13 1.93 3.93 38.00 1.11 1.89 .3.87 39.00 1.09 1.86 3.80 40.00 1.07 1.83 3.74 41.00 1.05 1.80 3.68 42.00 1.04 1.77 3.62 43.00 1.02 1.74 3.56 44.00 1.01 1.72 3.51 45.00 0.99 1.69 3.46 46.00 0.98 1.67 3.41 . 47.00 0.96 1.64 3.36 48.00 0.95 1.62 3.31 49.00 0.94 1.60 3.27 50.00 0.92 1.58 3.23 51.00 0.91 1.56 3.18 52.00 0.90 1.54 3.14 53.00 0.89 1.52 3.10 54.00 0.88 1.50 3.07 55.00 0.87 1.48 3.03 56.00 0.86 1.47 2.99 57.00 0.85 1.45 1 2.96 58.00 0.84 1.43 1 2.92 59.00 0.83 1.42 2.89 60.00 1 0.82 1 2.86 r j !n Z J J O O Z U Q � H FrO W H 0 U O Z E U N W N O I17N O LO n o W OI 01 V7 0I nO N "N 17 coo O 000 0 0 0 Q O 92 Z Z iii Q 1¢- J I I I I O n Z rn I I I I I I I 1 I I m 001 I I I I I I I 1 I 1 0 r 00 _ I I I I I I I N K N Q j j j I I I I I I I N 1 I I I I I I I J 11 I I I I I I I W O d 11 1 I I I I 11 1 'CE U Q O I I I 1 I I I I I I I I I I I I I I I 1 I I I I I I I I I I I I I I I I I I I I 1 1 I I I I I i 1 1 1 U I I I 1 1 1 I I I I I l 1 1 1 1 1 1 11 1 I I I I I I I I I I I O I I I I I I I I I I I I I I I I I LPL I I I I I I I I I I I 1 Z 1 1 1 1 I I I I I I 1 11 1 1 1 1 (T� -7W 1 1 I I I I I I I I I I I I I I I I I I i i i 1 I I I I I I J LL 11 1 1 I I I I I I m LPL I I 1 1 1 1 I I I I I I I I 11 1 I I I I I I I LPLLL I I I I I I I I 11 1 I l O j I I I I 1 1 1 I I I I I I I I I I I I I I I I I I I I Q I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I 11 1 O I I I I I I I I I I I I I I 11 1 11 1 T i I I I I I I I I I 1 I I I I I I I I I I I I I c I I I N I I I I I I I I I I 1 I 0 I I 1 i 1 I I I I I I I 1 I I I I O I I I I 1 I I I I I I F t f/1 I I I I n I I r I Q I I I J. Q I I 10 1 I ~ I O i I LL Z I N EN in~ 0 � F I 1 r N W T N W r d¢(r J I Z A V Q Q V Q vi W H W NO d' Q U O I V Z 1 F W Q V) f/l J� W Q N W Q O Q (n It J J 40 1w W �4 -DRAINAGE CRITERIA MANUAL TABLE 3-1 (42) RECOMMENDED -RUNOFF COEFFICIENTS AND PERCENT IMPERVIOUS ' LAND USE OR PERCENT FREQUENCY 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 1/2 Acre Lot or Larger * .30 .35 .40 .60 Apartments 70 .65 .70 .70 .80 ' Industrial: Light Areas 80 .71 .72 .76 .82 Heavy Acres 90 .80 .80 .85 .90 Parks, Cemetaries: 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 Undeveloped Areas: Historic Flow Analysis- 2 (See "Lawns") ' Greenbelts, Agricultural 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 Drive and Walks: 96 .87 .87 .88 .89 Roofs: 90 .80 .85 .90 .90 Lawns, Sandy Soil 0 .00 .01 .05 .20 ' Lawns, Clayey Soil 0 .05 .15 .25 .50 RUNOFF ' - NOTE: These Rational Formula coefficients may not be valid for large basins. *See Figure 2-1 for percent impervious. 11-1-90 n nn•u nnAIUA^r •un r, nnn n.,-�n•nr I I 1 Appendix D 1 I I 1 1 I I I i 1 �M O co ' C C N O C 11 N v W to co N O N c LL co 10 N N O � � M N II Vl ' N l0 3 c 11 II U O. @ U N 1=0 cc Je v N Y c 00(7 a�' a W ;m o @� a a Fw ° a n F Z o o N � C 0 CL H DDT II 11 II O rn I U _y JLLD UA N N 7 O � U F D l L O c W LL c O y Z F- Q UUm p O O Q m �0. . c m �. OQU a > m �i LL U O W� VII LV W pMv)p co _ U�Ix 0 11 LL mcnco0n O0 NCDcoNO > a °r° rn II 00 y C " N O O O N N O r- O 2 �CCj� ��Lo QO(h b w O O .. In O F w C 033 n O .� ? v 8 O F N r CD — L >L 000L �t0 G/ rn co�3�� m W 0 `c4) L-CL 7 O y p U p D 2 0.2 O 0 y y d N N C • E Y 11 7 0 N N g 2 om 0 y�z�ncc9 m y N yE8880c 00 N M V LO O 17 U U Y N y ov md�c= W3t C O d' g H w II p N �.�.. H O'pw a 11 1 11 a 11 Nn N N 10 LON T 6 O Z,1 ZaZ 7 Si NZLL�fn O NNgW COa. X LLdLLN W UCO) 0 2 u oqo co O N C6 0 O O II N r corn fO�N cn O m w In ITco N th (D OD LL (O cn _T U G (0 to U w in 5 m U Y N c } U+ } 'V 0 Co 1a a It moo u n. 11 11 m Q U N —IT inN CY0c0a am Ucli ma) m E 3m o } `o m '� d r L m QC y 0 v Ol 9F LL c 0 Q ? W a CL v to I N «O U O O Cl zo N DOLL d O� O � + OD W O Qm IU O O IT � U U m O LL S ' O W (J° (Oj If)ci O o 00 cn n In X O 'D . U11 W U O N00 co Np to Uop C7 ZioLU E > cc t I[Oo OD C C _ (ON(��� I�O� O C O O Uw o L C w CD d � m > U �U G N O g N O 7 U O: yw co C�f0 ...-`s '3 — O N 2d41 O-6 o O' O E 3 Eja d O O O oN NNOyUC N� E a °'yNII mi Q mm0 O� U J 3 �Ot m 0 N m V 1n O O O Y N O U U U N CL W m cm cm J(y m E'3 C �oU o� FEg p� a �'! �� 11 a 11 11 11 oD • d L: L z H — > N N N N W T S ozEIL az woo ct t� N uzU. In � 0 O O N N to aa`iz S W mo J I i 1 i 1 1 1 1 1 1 1 1 105: 0203.00 Date: 02/27/02 Scale: 12 MDesigned BW INITIAL STORM THEORETICAL GUTTER CAPACITY . CALCULATIONS D"IS, MILLER & WOHNRADE CIVIL ENGINEERS, INC. 1435 Wed 29th Street. La Wed, Colorado, BDSW 17, Phone: (970)461-2661, F= (970)461-2695 Sheet Shoots 1 Project: LCS: '0203.00 Date: 02/27/02 Scale: rDesigned De�e'gnW By MAJOR STORM THEORETICAL GUTTER CAPACITY CALCULATIONS D"IS, MILLER & WOHNRADE CIVIL ENGINEERS, INC. t= 1435 Wed 29th Street Loveland. Colorado, 005M w^" Phone: (970)461-2661, F. (970)461-2665 Sheet 8heete j Proect: ra0203.00 Dote: 02/27/02 Scale: g Desi umew LIBERTY COMMON SCHOOL TYPICAL STREET CROSS-SECTION DAVIS, MILLER & WOHNRADE CIVIL ENGINEERS, INC. 14M Weal 2M Street, Loveland. Colorado. am Phone: (870)461-2661. Fan (670)461-2665 Sheet Sheets 1.0 .9 7 3 .O 0 —S F- 0 B Le s:0.4% c:0.5 I T- I _'N _ I Ll I I � I I 1 BELOW ALLOWABLE STREET , i MINIMUM GRADE 1 I f ' I 1 :i 2 4 6 B 10 12 14 SLOPE OF GUTTER (%) Figure 4-2 REDUCTION FACTOR FOR ALLOWABLE GUTTER CAPACITY Apply reduction factor for applicable slope to the theoretical gutter capacity to obtain allowable gutter capacity. (From: U.S. Dept. of Commerce, Bureau of Public Roads, 1965) MAY 1984 4-4 DESIGN CR(TER1A I 1 1 1 1 1 1 1 1 1 1 [J 1 i 1 1 Appendix E 1 1 ' STRUCTURAL BEST MANAGEMENT PRACTICES DRAINAGE CRITERIA MANUAL (V. 3) ' site regardless of in -situ soil type. If sandy soils are present, the facility can be installed without an underdrain (infiltration option); sandy subsoils is not a requirement. This BMP has a relatively flat surface 1 area, and may be more difficult to incorporate it into steeply sloping terrain. 5.3.3 Pollutant Removal. Although not tested to date in the Denver area, the amount of pollutant removed by this BMP should be significant and should equal or exceed the removal rates provided by sand filters. In addition to settling, PLD provides for filtering, adsorption, and biological uptake of constituents in stormwater. See Table SQ-6 for estimated ranges in pollutant removals. 5.4 Design Considerations ' Figure PLD-1 shows a cross-section for a PLD. When implemented using multiple small installations on a site, it is increasingly important to accurately account for each upstream drainage area tributary to each PLD site to make sure that each facility is properly sized, and that all portions of the development site are directed to a PLD. ' 5.5 Design Procedure The following steps outline the PLD design procedure and criteria. ' 1. Basin Storage Volume Provide a storage volume based on a 12-hour drain time. A. Find the required storage volume (watershed inches of runoff): ' Using the tributary areas imperviousness, determine the Required WQCV (watershed inches of runoff) using Figure PLD-2, based on the PLD 12-hour drain time. ' B. Calculate the Design Volume in cubic feet as follows: Design Volume = CW Q2 V J Area In which: J Area = The watershed area tributary to the extended detention pond (square feet) 2. Surface Area Calculate the minimum required surface area as follows: ' Surface Area = Design Volume in 0 day in which, day = average depth of the PLD basin. ' 3. Base Coarses Provide base coarses as shown in Figure PLD-1. 4. Subbase If expansive soils are a concern, install an impermeable membrane and place the base coarse on top of the membrane. If soils are not expansive, use geotextile fabric to line the entire basin bottom and walls. ' S-30 9-1-99 Urban Drainage and Flood Control District DRAINAGE CRITERIA MANUAL (V. 3) STRUCTURAL BEST MANAGEMENT PRACTICES c _ 5. Average Depth Maintain the average WQCV depth between 6" and 12". Average depth is defined as water volume divided by the water surface area. 6. Sand -Peat Mix Provide a minimum of a 12-inch thick layer above the base course Filter Layer consisting of a thoroughly mixed ASTMC-3 Sand and Peat for filtration and adsorption of constituents. 7. Irrigated Vegetative Provide a sandy loam turf layer above the sand -peat mix layer. This Layer layer shall be no less than 6-inches thick, but a thicker layer is recommended to promote healthier vegetation. 5.6 Design Example Design forms that provide a means of documenting the design procedure are included in the Design Forms section. A completed form follows as a design example. s-1 _ss Urban Drainage and Flood Control District S-31 STRUCTURAL BEST MANAGEMENT PRACTICES DRAINAGE CRITERIA MANUAL (V. 3) SLOTTED CURB IN FLOW oPTIONAL 100 YEAR DETENTION 'WOCV WATER SURFACE —, IRRIGATED TURF GRASS, DRYLAND GRASSES, AND OTHER PLANTINGS — SANDY LOAM _ INLET TURFLAYER W AOUN., 12' MAX. AVERAGE DEPTH j - TS%ASTM G33 SAND _ 25%PEAT MIX 1W MIN j GRAVEL LAYER (C(COOTSECT.AASRTO NB COARSE AGGREGATE) IMPERMEABLE LINER J IF ON EXPANSIVE SOBS, OPTIONAL R -� OTHERWISE USE DETENTION CONTROL COOT GEOTEXTILE LINER 3 TO d INCH DIA PERFORATED PIPE UNDERLAIN CONNECTED TO INLET (MAY BE ELIMINATED IF UNDERLAYING SOILS ARE SANDY) FIGURE PLD-1 Porous Landscape Detention S-32 9-1-99 Urban Drainage and Flood Control Dishid DRAINAGE CRITERIA MANUAL (V. 3) STRUCTURAL BEST MANAGEMENT PRACTICES 0.50 0.45 0.40 0.35 r o.3Z 0.30 a 0.25 3 0.20 3 0.15 0.10 0.05 0.00 0 d Detention Basin Drain Time wr3rv=A•m or3-1 joi2+n 7ai 6-hrdraintime a=0.7 12-hr drain time a = 0.8 - 24-hr drain time a = 0.9 40-hr drain time a = 1.0 Detention and Porous Landscape Detention 12-hour Drain Time 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 Total Imperviousness Ratio (i=1„911W ) 0.9 1 FIGURE PLD-2 Water Quality Capture Volume (WQCV), 80"' Percentile Runoff Event 9-1-99 Urban Drainage and Flood Control District S-33 Designer: M.Wohnrade Company: Davis, Miller & Wohnrade Civil Engineers, Inc. Date: February 11, 2002 Project: Liberty Common School Location: Fort Collins, Colorado 1. Basin Storage Volume ( la = 100% if all paved and roofed areas u/s of PLD) le = 90.00 % A) Tributary Area's Imperviousness Ratio (i =1a/ 100 ) i = 0.90 B) Contributing Watershed Area Including the PLD (Area) Area = 18,918 square feet C) Water Quality Capture Volume (WQCV) WQCV = 0.32 watershed inches (WQCV =0.8`(0.91-13_1.19'12+0.78'1)) D) Design Volume: Voles _ (WQCV / 12) ' Area Vol = 506.4 cubic feet 2. PLD Surface Area (ApLD) and Average Depth (d,) ApLo = 1,012 square feet (da,,: _ (Vol / APLD), Min=0.5', Max=1.0') de = 0.50 feet 3. Base Course (See Figure PLD-1) x 6" (Min.) Sandy Loam Turf Layer, Plus 18" (Min.) Layer of 25% Peat and 75% Sand Mix, Plus 9" (Min.) Layer of ASSHTO #8 Coarse Aggregate (CDOT Section 703 Specification). Other: 5. Draining of porous pavement (Check a, or b, or c, answer d) Infiltration to Subgrade with Permeable Based on answers to 5a through 5d, check the appropriate method Membrane: 5(c) checked and 5(d) = no a) Check box if subgrade is heavy or expansive clay Underdrain with Impermeable b) Check box if subgrade is silty or clayey sands Membrane: 5(a) checked or 5(d) = yes c) Check box if subgrade is well -draining soils Underdrain with Permeable Membrane: d) Does tributary catchment contain land uses that may have 5(b) checked and 5(d) = no petroleum products, greases, or other chemicals present, such as gas station, es no Other: hardware store, restaurant, etc.? x Notes: Design Forms.xls, PLD DRAINAGE CRITERIA MANUAL RUNOFF C .d TABLE 3-1 (42) OECOMMENDED•RUNOFF COEFFICIENTS AND PERCENT IMPERVIOUS LAND USE OR PERCENT FREQUENCY 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 .80 112 Acre Lot or Larger * .30 .35 .40 .60 Apartments 70 .65 .70 .70 .80 Industrial- Light Areas 80 .71 .72 .76 .82 Heavy Acres 90 .80 .80 .85 .90 Parks, Cemetaries: 7 .10 .18 .25 .45 Playgrounds: 13 .15 .20 .30 .5C Schools: 50 .45 .50 .60 .7C Railroad Yard Areas 20 .20 .25 .35 .45 Undeveloped Areas: Historic Flow Analysis- 2 (See "Lawns") Greenbelts, Agricultural Offsite Flow Analysis 45 (when land use not defined) Streets• Paved 100 Gravel (Packed) 40 Drive and Walks: 96 Roofs: 90 Lawns, Sandy Soil 0 Lawns, Clayey Soil 0 .43 .47 .55 .65 .87 .88 .90 .93 .40 .45 .50 .60 .87 .87 .88 .89 .80 .85 .90 .90 .00 .01 .05 .20 .05 .15 .25 .50 NOTE: These Rational Formula coefficients may not be valid for large basins. *See Figure 2-1 for percent impervious. 11-1-90 9nnsu nnl t.0 n� •Nn rI nnn nnurnn� n.nrn.nr Appendix F Rainfall Performance Standard Evaluation Project: Liberty Common School STANDARD FORM A Calculations By: M.Wohnrade Project No.: 0203.00-LCS Client: The Neenan Company Date: 04/02/02 DEVELOPED ERODIBILITY Asb Lsb Asb* Ssb Asb* Lb Sb PS SUBBASIN ZONE (ac) (ft) Lsb (%) Ssb (ft) (%) (%) 1 HIGH 4.6 295.0 1357.0 1.20 5.5 J357 0 < h ., . 5 5 , '295 ;120 77.7: EXAMPLE CALCULATIONS Lb = SUM(Asb*Lsb)/A Sb = SUM(Asb*Ssb)/A PS (during construction) = 77.7 (From Table 8-A) PS (after construction) = 77.7/0.85 = 91.4 FADMWProjeds\LcsU.csECFon Awpd Davis, Miller & Wohnrade Civil Engineers, Inc. L Effectiveness Calculations Project. Liberty Common School STANDARD FORM B Calculations By: M. Wohnrade Project No.: 0203.00-LCS Client: The Neenan Company Date: April 2, 2002 EROSION CONTROL METHOD C- P- Comment Factor Factor Value Value Roads / Walks 0.01 1.00 Existing roads and walks Established Grass 0.03 1.00 Existing playground Gravel Filters 1.00 0.80 Placed at existing curb inlet Silt Fence 1.00 0.50 Surrounding the gymnasium PS SUB- AREA CALCULATIONS MAJOR (%) BASIN (AC) BASIN 1 77.7 4.6 DURING CONSTRUCTION: Plan intent: Erect silt fencing and place a gravel inlet filter at the existing curb inlet. Impervious: Impervious area = 1.9 acres Pervious: Established Grass = 2.7 acres Weighted C Factor= ((0.01*1.9)+(0.03*2.7)/4.6 = 0.022 Weighted P Factor= 0.8*0.5 = 0.40 EFF = [1-(C*P)]100=(1-(0.022*0.40)100 = 99.1 > 77.7 F:\DMW\Projects\Lcs\LcsECFormB.wpd Davis, Miller & Wohnrade Civil Engineers, Inc. 0 o IcNaNDOO to 1 CO W CO CO m O a �a a° O U 3 o mmmm000000 O e4eetotoL1L( tcito e WWWmWmmmWW o ma+rnato,rnato,rnao+o,000 o eeevvvveva vvtntntn o rmmmo�o,o+o+o+mrna�o�a+o�o�rno+o+o+ . . . . . . . . . . . . . o e v v e e e e e e e e e e e e e v e v v N W W m W W W W W m W m W m W W W W W W W 0 oMetntotototurrrrnrrrnrrrmmmWmm . . . . . . . . . . . . . . . . . . o vevvvevvvvevvvvvevvvvvvvvv r♦ W m W CO W CO W W CO W CO W W W W CO W W W CO CO CO CO CO CO CO O mNMvtntntn%o%ot0%o%a%orrnnrn.r.rnn.W m W a1 M e v v v v e v v v v v v* v.v* e.ee ve v v v e e e v v m CO W W CO W W W W W m W W CO W W W CO CO m m m W W CO CO o w o N M v vW U1 to to tD to w to to to m to to to r n r r 1n r . . . . . . . . . . . . . . . . . . . . . . cm en -W-Wv e e e e e e e e v v v v v v v e e v e e e IT CO CO W W W W CO W CO CO m W CO CO W W CO W CO W CO m CO W CO W O ear.ir4mm eeetnlnu)Lmtn1ntnino%o%o%o%o%otpr .................. r M M e e e e e e e e e e e e e e e e e e e e e e e e m m W m m W W m W m W m W W W m W W m W m m m m m m O Ota W Ori.-INNMMMMee V'eeeeetnNtnu'1tOtp . . . . . . . . . . . . . . . . . . . . to r'+M�vevvevvvvvaveeeeeeevvvv comWmWWmmmmWWmmmmWWmmmWWmmm r 0 MNMrrW M00Hf-I rI N N N N N M M M M M e e e ee eN+ .... to N M M M M M e e e e e e e e v v e v v e e v e e v v m W W m m W W W W m m m m m m W m W m m W m m m m W W Oin rAm.-Imam wwrt rrWmmmmmmmm00000 . . t4 v N N M M M M Mr; M M M Mr; M M M M M M M M v v e v e rn eoWWmcoWWmaoWmWWmWWWWWmWmWWmW O t0u1 W 0r•4N M e vin00 0 W W Wbrr'rr W W co chON . . . . . . . . . . . . . . . . . . . . . . m m W CO 0D W m m m W W m m m m m m m m W m m m m m m to .e.a0rr000r4NNMMMeeeee0tnln�oto�orn M r .i N.N.N.N.f•.1 1".1 !' 1.!' .1 M.M M M M M M M M.M M M M M M M M COmm W WiaW W mmWm Wmmm W CO mmmmmmmm O MN10W atOriNNMMMeeeV'evtMtoW toWW 0W . . . . . . . . . . . . . . . . . M O rl.-I.-Ie-INNNNNNNNNNNNNNNNNNNNN m CO m m m m CO W W m W W W W W W W W W W W W m m W m M tnn etnwnrrmmmmmmma m000000 ............... N rmoomWWmWmmmmmmmmmmWmmmmWWm O em 0 m 0 0 0 W m 000.4t t.-t.-t NNNNMMMMMM . . . . . . . . . . . . . . . . . . . . . . . . N m a1 O O O O O O ri ry ri ri ri '1 r♦ ri ri ri ri ri ri ri ri r♦ rr ym co co co co orm Wm 111mmmmmmmrn etmmmm W m to mNjOD.-i V!Iflrnm0 M00.-I.-I.4r4r4NNNMenMMM .• . . . . . . . . . . . . . . . . . .-i\DmI0atmmatmtTmmoo00000o0000000 ir- r-I r- N r- r- r- r- N r- i- c co WmmmWmWmmmW W..m- o toMloero�or�NMMvd tntntntn�c�ototorn�oto�c ator-rrrWmWmmmmW WmW WW Wm WmWmm rr:�rrnrrrrnnrrnrrnrnnnrnrr m o1o%E mrmW rrr%otototoveMMNNal%0vrim%D . O O N N N N N N. N. N. N. . . . N. N. . N. N. N 14 ri 14 e. 0. . 0 rrnrnrrrrrnrrnnrrnrrnrnnrn s H.� o0000000000000000000000000 CH 00000000000000000000000000 zk. riNMetAtOnmtTO.�NM V Wwr,woOtoomono a`' r•1 .-I ri rl ri r•1 ri ri rl .-1 N N M M e e to tt Q ►0 .J �U 2 Table 88 C-Factors and P-Factors for Evaluating EFF Values. G t r t Treatment C-Factor P-Factor BARE SOIL Packed and smooth................................................................ 1.00 1.00 Freshlydisked........................................................................ 1.00 0.90 Rough irregular surface........................................................... 1.00 0.90 SEDIMENT BASIN/TRAP................................................................. 1.00 0.50111 STRAW BALE BARRIER, GRAVEL FILTER, SAND BAG ........................ 1.00 0.80 SILT FENCE BARRIER..................................................................... 1.00 0.50 ASPHALT/CONCRETE PAVEMENT ................................................... 0.01 1.00 ESTABLISHED DRY LAND (NATIVE) GRASS .......................... See Fig. 8-A 1.00 SODGRASS................................................................................. 0.01 1.00 TEMPORARY VEGETATION/COVER CROPS .................................... 0.45121 1.00 HYDRAULIC MULCH @ 2 TONS/ACRE........................................... 0.10171 1.00 SOILSEALANT....................................................................0.01-0.60(•1 1.00 EROSION CONTROL MATS/BLANKETS............................................ 0.10 1.00 GRAVEL MULCH Mulch shall consist of gravel having a diameter of approximately 1/4' to 1 1/20 and annlied at a rate of at laaar 1'ir, rnnc�e.rn n nr ., HAY OR STRAW DRY MULCH After olantino orass seed, apply mulch at a rate of 2 tons/acre Iminimum) and adequately anchor, tack or crimp material into the soil. Slo 6 11 to 10 ............................................................................. 0.06 1.00 16 to 15 ............................................................................. 0.07 1.00 - 21 to 20 ............................................................................. 0.11 1.00 to. 25 ............................................................................. 0.14 1.00 25 to 33 .............................................................................0.17 1.00 > 33 .......................................................................... 0.20 1 on NOTE: Use of other C-Factor or P-Factor values reported in this table must be substantiated by documentation (1) Must be constructed as the first step in overlot grading. (2) Assumes planting by dates identified in Table 11-4. thus dry or hvdral dir ml drhPc arP nnr ran..;rdl (3) Hydraulic mulches shall be used only between March 15 and May 15 unless irrigated. (4) Value used must be substantiated by documentation. �P.:IISTING 12 WIDE cR')ss oaN G VIP 01;: 1s .one cut TPROVOM "tfT cuRO • p0Si1N0.IF �n\ [� go ft,12 SECT f _ THRU SWA Li r—. t. -Lc --� II 'c<vAClry 9c 7 fs co N>iR �y� ` .� gyp' , . VELOCITY: S•LG c/ .� �t�.VHs ,) - / • i 100 YEAR HAW- 89.9 SFr �s.l>1-� ,.ntiwo- i-r._ I I r4 _.:, '.w 1 , .,�J •;2. 73 �fc, -. j I % / / L , x- 0 .. E \ C \ // �/ e Tpynws@r // /II>'///, ,'/ .j., if I � '' d �• � / LEGEND C W GXISTWG C01+,0 / FO / ? / / G ➢HUPOfED fANTJVR ' P' ` x'pp A GVILDING B' ils OFFSf TE Z/]\ a p . ASPNPIT PF•/EMEAIT FROM FLOW ) ix QL S AG DEUFLOPED / - /. 4-2 AG r L. T8:.. Y?i • ynwln % }^J.` ' Z Qre 0'7 efs /J///' / SUB-3A5/N 64tt z ' Q�-•3.1 c(r qa 3,10 efs •K -�; 1 LOW DIREC i.10N ARROWf i.Y.YP J it t / 'LTh' ? :.' I :� �\�� 4 / .. .I \ I I k a x / Y { �}q; q * �y a• 'IIl' E�T11 - � O o fl f jt J ] 4 / 3. LLJ ��. '� ^+a \\\ ,1\ fQ iui /0p��,, BG cL tF` I. Y• (�% *�.^A+ryi DRAWNA 6E TASLE SU6•BPSq.I AI{EA r0i.!; 010 0too .1 1.41 AC 2.T3 off Mel cif I. se cf; 2 1.4Z Ac 3.16 cff s.ar c r 9.94 cff 3.12 Ac 6.OG efr. 10.09 {f v.64 efs -_ C i W NV �TGkF tu I `:\ `' -. a* �': >•L >. y f.� f� � �i�. „-c #r SI cl l�� c eref �.cr_ rL uV z ? 1 T W`• FV � Oy SIy.�P`J/` TrB� B Bu.Lr /N z IL Q D '' , *'' -% / y-. q. ;� •:j L '._SPO CYVATie.J2:TAtG ./MOW:J AS 03)." { I _--f'_ i �•... _ f-` ;'1 a- �/ > i { r 't f >.`?"asr.31.>r."'+r>�i r.•1[' C j �4p 101G e# .•, ` � .. 31.. 'P>t��i DRAWING 117- a , •ist� xry a? A:..i .tea r i '. ':'.r' •L.. x r!:'.:T-t .. 1'.. �.i.�r.E a, et• •.' � �'I�i�x PY4. a'S]�i1.+t.�r_A:xnt' .%