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HomeMy WebLinkAboutDrainage Reports - 08/01/2013City of Ft. Collins rove PIa1 ,s Approved By Date -� l FINAL DRAINAGE AND EROSION CONTROL REPORT FOR NIX FARM NATURAL AREAS FACILITY MAJOR AMENDMENT Prepared for: City of Fort Collins Operation Services 300 LaPorte Ave., Building B Fort Collins, CO 80521 (970)221-6273 Prepared by: Interwest Consulting Group 1218 West Ash, Suite C Windsor, Colorado 80550 (970) 674-3300 May 13, 2013 Job Number 1165-012-10 No Text ' TABLE OF CONTENTS TABLEOF CONTENTS............................................................................................................ iii ' 1. GENERAL LOCATION AND DESCRIPTION................................................................ I 1.1 Location...........................................................................................................................1 1.2 Description of Property................................................................................................. 1 ' 2. DRAINAGE BASINS AND SUB-BASINS.......................................................................... 2 2.1 Major Basin Description................................................................................................ 2 ' 2.2 Sub -Basin Description................................................................................................... 2 ' 3. DRAINAGE DESIGN CRITERIA..................................................................................... 3.1 Regulations......................................................................................................................2 2 3.2 Directly Connected Impervious Area (DCIA) Discussion ........................................ 23 ' 3.3 Development Criteria Reference and Constraints...................................................... 3 3.4 Hydrological Criteria..................................................................................................... 4 3.5 Hydraulic Criteria.......................................................................................................... 4 4. DRAINAGE FACILITY DESIGN....................................................................................... 4 4.1 General Concept............................................................................................................. 4 ' 4.2 Specific Details................................................................................................................ 5 4.3 Drainage Summary........................................................................................................ 5 ' 5. CONCLUSIONS....................................................................................................................5 5.1 Compliance with Standards.......................................................................................... 5 5.2 Drainage Concept........................................................................................................... 6 6. REFERENCES...................................................................................................................... 6 APPENDIX A VIC MAP, DRAINAGE AND EROSION CONTROL PLAN, FIRM ' APPENDIX B HYDROLOGIC COMPUTATIONS APPENDIX C HYDRAULIC COMPUTATIONS (NA) APPENDIX D WATER QUALITY POND INFORMATION ' APPENDIX E MISC INFORMATION I 1. GENERAL LOCATION AND DESCRIPTION t1.1 Location ' Nix Farm Natural Areas Facility Major Amendment is a proposed office building for the City of Fort Collins Natural Resources Department at their existing Nix Farm Natural Area Campus. The site is located north of the Burlington Northern Railroad Tracks, west of Timberline Rd, south of the Cache La Poudre River, and east of Lemay Avenue. The project is located in a portion of Section 18, Township 7 North, Range 68 West of the ' Sixth Principal Meridian, in the City of Fort Collins, Larimer County, Colorado. A vicinity map is provided in Appendix A. ' 1.2 Description of Property U n 11 The site contains approximately 27.48 acres; however, the proposed new office development will disturb approximately 0.7 acres. The site is zoned POL, Public Open Lands. The project will construct a two-story, 4000 sf office building located just west of the existing maintenance building. Sidewalks and additional parking will also be constructed. This drainage report will examine the runoff changes associated with increasing the existing impervious area only. The existing lot is already developed and equipped with an existing water quality pond in place. According to the "Soil Survey for Larimer County Area, Colorado' (UDSA) soils for onsite and offsite basins include: Kim loam (54), Satanta loam (95) & Stonehem loam (103). The existing site drains from NW to SE at approximately 1.3% with good ground cover. See Appendix in the "Final Drainage and Erosion Control Report Nix Farm Natural Areas Facility", by JR Engineering (Nix Report) for soils map and information. The project is not with in any FEMA mapped floodplain. Please refer to Flood Insurance Rate Map (FIRM) Map Number 08069CO983H in Appendix A. n 2. 1 t 3. i DRAINAGE BASINS AND SUB -BASINS 2.1 Major Basin Description The site is located in the Spring Creek Drainage Basin and contains approximately 27.48 acres. The Nix Report has previously studied this site. According to this approved report and the conceptual review comments for the project, no detention is required for the basin. 2.2 Sub -basin Description This report will re-examine two sub -basins previously defined by the Nix Report, sub - basins 102 & 103. The drainage patterns of these two basins will remain the same; however, the percent impervious values will increase due to the addition of roof, sidewalk and parking areas. DRAINAGE DESIGN CRITERIA 3.1 Regulations This report was prepared to meet or exceed the "City of Fort Collins Storm Drainage Design Criteria Manual' specifications. Where applicable, the criteria established in the "Urban Storm Drainage Criteria Manual" (UDFCD), developed by the Denver Regional Council of Governments, has been used. 3.2. Directly Connected Impervious Area (DCIA) Discussion Urban Drainage and Flood Control District (UDFCD) recommends a Four Step Process for receiving water protection that focuses on reducing runoff volumes, treating the water quality capture volume (WQCV), stabilizing drainageways and implementing long-term source controls. The Four Step Process applies to the management of smaller, frequently occurring events. Step 1: Employ Runoff Reduction Practices To reduce runoff peaks, volumes, and pollutant loads from urbanizing areas, implement Low Impact Development (LID) strategies, including Minimizing Directly Connected FA I I 11 I fJ 1 0 I 0 I Impervious Areas (MI)CIA). Runoff for the site will be routed through vegetated areas through sheet flow thereby reducing runoff from impervious surfaces over permeable areas to slow runoff and increase the time of concentration and promote infiltration. Runoff will also flow through grassy swales which also slow runoff and promote infiltration. Step 2: Implement BMPs that Provide a Water Quality Capture Volume with Slow Release Once runoff has been minimized, the remaining runoff shall be treated through the water quality pond located south of the project. Step 3: Stabilize Drainageways Natural Drainageways are subject to bed and bank erosion due to increases in frequency, .duration, rate and volume of runoff during and following development. Because the site will drain to an existing water quality pond, bank stabilization is unnecessary with this project. Step 4: Implement Site Specific and Other Source Control BMPs Proactively controlling pollutants at their source by preventing pollution rather than removing contaminants once they have entered the stormwater system or receiving waters is important when protecting storm systems and receiving waters. This can be accomplished through site specific needs such as construction site runoff control, post - construction runoff control and pollution prevention / good housekeeping. It will be the responsibility of the contractor to develop a procedural best management practice for the site. 3.3 Development Criteria Reference and Constraints The Nix Report was completed on February 6, 2001 and revised June 8, 2001. This report outlines the drainage features for the entire 27.48 acre development. All calculations and design provided herein adhere to the approved overall drainage report. 3 I I 3.4 Hydrological Criteria ' Runoff computations were prepared for the 2-year and 10-year minor and 100-year major storm frequency utilizing the rational method. ' All hydrologic calculations associated with the basins are included in Appendix B of this ' report. Due to modifications of surface type only, Sub -basin 102 will encompass 0.38 acres and is calculated to have 2-year, 10-year, & 100-year discharges of 0.4, 0.6, and 1.6 cfs, respectively. Sub -basin 103 will encompass 1.22 acres and is calculated to have 2- year, 10-year, & 100-year discharges of 1.3, 2.3, & 5.9 cfs, respectively. Both sub -basins 102 & 103 will still be routed through the existing water quality detention facility. ' The Nix Report weighted average percent impervious value of drainage Basins 102, 103 ' and 105 treated in the water quality pond is 19%. The weighted average percent impervious value of the revised drainage Basins 102, 103 and 105 treated in the water quality pond is 21 %. The water quality storage volume was calculated to be 0.07 ac-ft, unchanged from the Nix Report. The volume is provided by the existing design and is enough capacity to account for the small increase in impervious areas made to sub -basins 102 & 103. Water quality ' volume was calculated using the method recommended in the "Urban Storm Drainage Criteria Manual". All pond calculations are in Appendix D of this report. ' 3.5 Hydraulic Criteria ' No hydraulic structures were added or modified per this report; therefore, no hydraulic calculations have been provided. 4. DRAINAGE FACILITY DESIGN 4.1 General Concept The majority of the proposed development will be collected and conveyed to the proposed water quality pond on the southern most portion of the site where it will be ' allowed to settle before being released into the adjoining drainage easement to the southeast of the property. 4 4.2 Specific Details A summary of the drainage patterns within each basin is provided in the following ' paragraphs. ' Basin 102 includes the area west of the Maintenance Building, and east of the existing access road loop centerline. This runoff will be collected and routed through a proposed ' 12" CMP and existing 15" RCP culverts and conveyed to the existing water quality pond. Basin 103 includes the area north and east of the Maintenance Building bounded on the north and east by the access road loop centerline. This runoff will be collected and routed through a proposed 12" CMP and existing 12" CMP and 15" RCP culverts before being ' conveyed to the existing water quality pond. ' 4.3 Drainage Summary The existing water quality pond was originally designed to hold and treat a volume of 0.72 acre-ft. The water quality capture volume calculated for the additional impervious area continues to be 0.07 ac-ft. Therefore, the existing pond is still adequately sized to ' handle all runoff changes from sub -basins 102 & 103 and no modifications to the outlet structure are required. ' S. CONCLUSIONS t5.1 Compliance with Standards ' All computations that have been completed within this report are in compliance with the City of Fort Collins Erosion Control Reference Manual for Construction Sites and the ' Storm Drainage Design Criteria Manual. 1 5 5.2 Drainage Concept The proposed drainage concepts presented in this report and on the construction plans adequately provide for stormwater quantity and quality treatment of proposed impervious areas. Conveyance elements have been designed to pass required flows and to minimize future maintenance. If, at the time of construction, groundwater is encountered, a Colorado Department of Health Construction Dewatering Permit will be required. 6. REFERENCES 1. City of Fort Collins, "Storm Drainage Criteria Manual", (SDCM), dated March, 1986. 2. Urban Drainage and Flood Control District, "Urban Storm Drainage Criteria Manual", Volumes 1 and 2, dated June 2001, and Volume 3 dated September 1999. 3. JR Engineering, LLC, "Final Drainage and Erosion Control Report Nix Farm Natural Areas Facility", dated February 6, 2001 (revised June 8, 2001). 0 APPENDIX A ' VIC MAP, DRAINAGE AND EROSION CONTROL PLAN, FIRM I-1 r M. 1 1 1 1 1 1 i 1 1 1 1 1 1 1 1 i 1 i VICINITY MAP SCALE: 1 " = 1000' SITE D I I I 1 1 I I C ♦ / �� 104 \ �� �• / o //// �� / 0.7I 0.44 C 100 GOT/ Y� -f N/XFARMNATU/ L • � a w.,cP +. , I A0ZCASFACl5L/TY10 I / AfF A[4N^ `\\ �< / ;I9J�nl / _ - HOFFM E r = "i'Z '�.zn, ns-.ereJ ' - MILL RD ce �uRTs aF ` ♦ `�. �l� \ �rT7'�'il> rrrone� - X ITBE 00 1 w • ` • 1.22 0.58 TT-.�� - i \`tl I I; • s wNwNxttuN 1 • .. ,� ♦ 103 .ilEll BETm �TTG� \ / I d 1 —\\ IY 102 �F "'OmcxAE°uuz" I I I,Ire , ♦ I.zz oezo I/ 102TFFF] II 0.38 G.31 \ 1_ 1 yNmR ( v �Z II 8.4 / 1 3A D 33 I I 1 �\ \ 1 I r ♦ \ MV NYtWl9J (n'PK/ / \ \ \ \ `105 \ \14'— �� 41 ♦�� vV AAV v 14 a 41� I I\ \\\ \ \ / llR aysrce atFE I 15_ l III OVERALL DRAINAGE SUMMARY TABLE I amm0m��0m a0m00®®®0 00"®00®000 a0®mom®®®® /// \ ILL 1 I COF1GTOi NTIIS.I Gcm ipmrp l a —aMoiril a ERD— — — —a In. wIN, _-- s lswWl p -- v IATNR WBUTAW Vesely Mm- -- -- ,,Sm, — ou RANEWD III Can•N SE 9PI IT ry13 In 1 I Fi - O BB ap SIF Bn _ STEM Ray __ Curl F _ A (IINxC BAR, Om _ _ v . NeePlan4p M N9 nl T pl ry SxE Pon np _ _ S. 11 Wlati _ _ x leXpmNNwBID�A. — BOIUDNGCOISTROCTUN — NOTES STANO'SCOACHNTHE PF JECTTM cTiEAAMERSXAu LEGEND _ xX%X EXAPING MINOR CONTOUR 1.11 E.ISTNGmAiORCGMCUR _.X..-� PROPOSEDMINORCONTIOUR �x...l PROPOSED NA,GRCGNTOUR AAAAER DRAINAGE BASIN OmUE uvE G.5'J.6: EXDRAiNAGEA/RNARFA EFFICIENT ROPoa.N.PIN PSNAR BER 0.3 B PROPw.iDR=E.RUNOFFCGEFFIGIENT QDESIGN SOIM EA ® CONCRETE WASXOUi OCONSTRUCTiCHC. gNCE O\ WATTLES CALL UTILITY NOTIFICATION CENTER OF COIORADO 811 w C Nyy ]-BUSIXER DAK IN bVNIQ ,I \ RSOIE BID DBA OUSE. OR E%GVA- \ FOR BM BE Iwommwro YOIRA UTURC, W Z N f 7 W -I j00 J _ ¢ D U W W N O I— U) E N m Z J N a 0OUN rc U. a W b a OW�rn FF 0 U00 z x w z W 0 z cW G O ti 30 15 0 3060 m m w E N u Z SCALE: I-= 30' In 0 r aJ u u a � o u CITY OF FORT COWNS, COEORADO UTILITY PLAN APPROVAL APPROWD: DIY ENOIEOI DATE CHECKED BY RAIN` k •AST'AIEA UTUTY DAM CHECKED BY: _ ST PER UTUTY DATE CHECKED BY: PYNS k REOR ,NM OAIE PROD. NO. 11850120t CHECKED BY: IRAFEAC ENDNEMB oTre 5 CHECKED BY: XARPK RESWRPFS OAM [l 11 1 1 APPENDIX B 1 HYDROLOGIC COMPUTATIONS 1 1 1 1 1 1 1 B s _ o RCl M Ci b l7 N 1� n N try�l 0 F F V e o 0 0 0 0 0 U o 0 0 0 0 0 0 R m N A l7 en- r � N �y 's 2. 2 k � & k) 2 !k : ƒ% d ƒk § 2 .!J 2} /tr § ■! § )} . \°( ((! r / )emu! !! E )�olmm#k | §§( !§!)|!5 |§« �§r■|■# m7# ■!§!)°° §§ ■e:ee!§ �/ k■!,|�»! | | | | | � § ! ( § § « § . E § e■, Jog f f/ ! k}2.5| � § $ k t|EQ !-|=�f 1; ! !( § $\ | k . k] \ » } k ` B !N� !■•■§«� ,T , ;!e ;■_;;;; � | ■mma.,, MOM \` \\,�,;. �r®®■■! - | ,#��■@( | ® || � ||R�&-, £. �, -- ■ 5§ §§■R .� | \ k ! zl k 2. 91 � kk ! !< . } !■ ± -It k _ }{ { } { § k ) I i 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 0 1 �3 �3 1. � �Y mnowrN� 6 E� m � H H Yl Yl N Z S O N ��2 �W 1117 .Y Z N O O Q m m W u a eriaon ri 1O �i yq 3 n W r N N n a Ep W Y��NOOON O Fig ��oeo`oo mmmmn cC occecoo W SSii E �r nnwnie nE g00000� dodddod �aU i Z I jOj, U C f S aC_ LL O 'U O a IL O N a 8 K m + LL � E N m � c � 0 y mn u � w = > '6 E E E R § §• !! 2;;;;;; f|� ;■� NOW ~` ■■§■■■K §-� ■■\■aa\ |�� !. TF, k MAH �� M A e �E� !r®■■ne ,!lmnq- � � )|° ` JE | _ §■a,2,� ! � k ! \ } { � � } ® A .§ k 7k ` !! t k+ / { � / ; � � & ( 2\ kkq §§[:. \kuo #£ ! � §!�» /. !§!§qq5 z/o ) .kk;e2l� # $ , k k} k222° ! k CwL �$o\/$ 11 � � o � E § ( \ .& ƒ dk kza �({M \ CL. k . # | 7!�) } £ ;;e§;;G -Ik §!l5355 ® k 2k2;;@; / 3!!|!(S # ngOVW-- k\). 2 kLL c _ {.k{\ § 21 k 2;•@| ! »§ff£ ! { £■f-f 3 3/{< § & - / 3 \ . � k k § U ❑.r N x_ z-�- u r o � N O_ zzF g On1 a H 9 .3 w 0 C Y g C o F 0 o ,�n wy V wwAn yam O o w V O E me g> c3394a 0 g b w n eooaw ,� a N O O t7 O V v 224 n n w 10 w A fD E Cd b lV b ppipp �wlVp ��bpp N N U 0o 6 fop (0V yyo0 0 z rc c y O NrlObbwn 0 2 � (71 LL a E w LD 0 t C v W V w N 8 c Y 0ti- - C 'm 2 o 11 II II 11 g � ' V n K 2 CL O a N I u I 1 I I I t APPENDIX C HYDRAULIC CALCULATIONS (NA) y I APPENDIX D WATER QUALITY POND INFORMATION 1 II 11 1 n 1 1 H 0 0 Pond Name Proposed Detention Pond - Stage/Storage LOCATION: NIX FARMS OFFICE PROJECT NO: 1165-012-01 COMPUTATIONS BY: MM SUBMITTED BY: 1NTERWEST CONSULTING GROUP DATE: 11/14/2012 V=1/3d(A+B+sgrt(A'B)) where V = volume between contours, W d = depth between contours, ft A = surface area of contour POND NAME WO WSEL- top of berm - Stage (ft) Surface Area (fe) Incremental Storage (ac-ft) Total Storage (ac-ft) 4926.28 0 4927 4681 0.03 0.03 4928 9850 0.16 0.19 4929 16315 0.30 0.49 4929.55 20506 0.23 0.72 4930 23935 0.23 0.95 VOLUME REQUIRED: 0.07 VOLUME PROVIDED: 0.72 detention.xls 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 i 1 1- 1 1 North Star �4*M.-.desi0n,. inc. October 1, 2002 Jay Barber City of Fort Collins 700 Wood Street Fort Collins, CO 90524 Mr. Barber, This letter is to, certify the water quality pond at.M)v,Fh= Natural Areas Facility. According to the attached.water quality, pond calculations completed by JR Engineering, the volume required in this pond is 0.07 acre feet According to the topographic survey of the water quality pond (copy attached), the pond as constructed has a volume of 0.72 acre feet before the pond will overtop the water quality structure at elevation4929.58. or if you need any additional information. 700 Automation Drive. Unit) Windsor, Colorado 6C55C 970.686.6939.Phone • 970-886-1188 Fax l 0', h " d%'l Proposed Detention Pond - Stage/Storage LOCATION: Nix Farms PROJECT NO: xx COMPUTATIONS BY: ppk SUBMITTED BY: NmM.Stir Design, Inc. DATE: 10/1/02 V = 1/3 d (A + B + krt(A'B)) where V = volume between contours, ft d = depth between contours, It A = surface area of contour Stage ft Surface Area (ty)(PC-ft Incremental Storage Total Storage ao ft) 4926.28 10 4927 4681 0.03 0.03 .4928 9850 0.16 0.19 4929 16315 . .0.30 0.49 4929.55 ZO506 0.53 0.12 4930 23835 0.46 1.18 Volume Required Volume Provided 0.07 Acre-ft 0.72 Acre-ft NixFarm_WQpond.xls I I I L 1 I I I No Text of 01 02 03:23p I .1 . 11 . Cattier CC412tru6tion. Ima 99C 221 46515"""— 10 Design Procedure Form: Extended Detention Basin (EDS).Sedimentation Factilt . y WATER QUALITY POND Peke" Name MIX FARM NATURAL AREAS FACILITY h'jfi:ctNvmbw. 39023.27 Ciummy. )I nwift B Dwisnon R STRAND Dow 6111001 1. flasinstemos Volume At T(bl" AreVS tmpwvbumM Ratb (MV100) % 8) CoMa3U6M WaWShad Area (Area) 9.19 A 6.17 aces C) Cl Water Quant, Capture Volume fwacv) . (WOW = 1 .0 * (0.91 1 0 - 1.10 1 F - 0.760) V=V- 0.11 wtershed nches D)De"9nVd=e:VO1-WOCV/l2 'Area- 1.2 VOL - ov ac-r. 2. Oudelftft A) Ouget Type tCheek one) 13) Depth 81 OUCUt Above La*&Al P&IOntlim IM C) Requ . bed MaXhMWM OUN Alga per Row. (Ao) (90MEBB-3) 0) Perforation Dwairsions (enw one only) 0 Gmhf 104domlion Vismiar OR Ill T HeW Rectsegular Pw%Mkm Width E) Number Of Columns (M See TWO 6a.i for mom). F) Actual Deso Outlet Area per Row (Aj G) Numbercl Rows (n* millowcoustAnta(A� & Wash Rock A) Needed Open Area: 6)TYPc*tOul101C"ft(Chv*Onq) C) For 2, or (WLM) from Tame !Q Hftht of Trash Rock Sam (FW 4".2"fartangoorlopRuppen 10) Type ol Sam Band an Depth H) Desaft it 0~ W SCIOCS OPffift Vot Dlmonsbl co$Cfta ff 11) SPKWv o(supw Rod (Oir.) TYPO and Sire Of 1340171 1od ght Table 69-2) A OfTice Plate — Ptrfa-aled Risor Poe Other. Hs —2 It AD= 0.10 Sqma jachoS V. vj inches. on, W.i inches Aso 0.15, "Wre 11whes nUMber As- Q45 A.- 15.3 gqAM k4haa X r0famewftimll —Otnor Wr Heim 22 lichn 5-3- 993 VE Wife (US FOW) Other. X 0.13r (M Fats) Other. 54 kichas 0156VECI p. 2 1 I 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 k APPENDIX E MISC INFORMATION E 1 FINAL DRAINAGE AND EROSION CONTROL REPORT NIX FARM NATURAL AREAS FACILITY Prepared for: City of Fort Collins Natural Resources Department Mark Sears, P.E. P.O. Box 580 Fort Collins, Colorado 80522 (970)416-2096 Prepared by: JR Engineering,LLC 2620 E. Prospect Road, Suite 190 Fort Collins, Colorado 80525 (970) 491-9888 February 61 2001 ,Revised June 8, 2001 Job Numbff W23.27 s O C/ C4 A l'7 lV m d S 4 ry n w A e n o ri R n a � J M Q v G OR e, A m A A fC� Iff O pp q g v o e o 0 0 0 0 0 W E ���RSGFte�. (7 Ct o 0 0 0 0 0 0 0 Z ///YQQQyyy. p W �i, w I' Q Q O� ci G Y � m A 5� g8gO�S� w � m O a a RUNOFF COEFFICIENTS & % IMPERVIOUS L.00A71ON: MIX FARM NAMRALAREASFAmny PROJECT NQ 39023.27 COMPUTATIONS BY: B. 57RfND DATE: 5125/01 Recommended Runoff Coefficients from Table 3.3 of City of Fort Collins Design Criteria Recommended % Impervious from Urban Storm Drainage Criteria Manual Streets, parking lots (asphaft) Sidewalks (concrete) . Roofs; Lawns (flat <2%: sandy soll): Runoff % coefficient Impervious C 0.95 106 0.95 96 0.95 90 0.10 0 JR Engineering 26W E. Pmsya0l Rd.. Sle. 190 Fort Colons, CO 8525 IN TOESIONATION TOTAL AREA TOTAL AREA ROOF AREA PAVED AREA (s08) SIDEWALK AREA (son) LANDSCAPE AREA. -(spit) RUNOFF COEFF.(eas) (C) % 0.38 143M 0 Z005. 0 13A45 0.25 � 18 1.22 53,354" 5,297 ' 19.353 0 28,704 0.49 45 104 0.71. 31,052 2385 oleo .0 21.718 0.36 . 105 4.57 199.107 8,082 17.557 0 175,468 0.20 12 102,103,105 6.17 264811 11,379 39.815 0 217,617 0.26 1 14 .106 1.31 59338 0 6979 0 51,359 0.20' 12 102,103.105,106 7.51. 327.149 11,370 447" 0 268,976 0.25 T7 107 1.31 50,851 0 4,608 1 0 f SZ245 0.17 8 Eauations Calculated C coefficients & % Impervious are area weighted C=E(Cl Al)/At Ci = runoff coefficient for specific area, Al Ai = areas of surface with n=ff coefficient of CI n - number of different surfaces to consider At = total area over which C Is applicable; the sum of all Ars 90msfl wxb � k� ■§� . |0 . . o§ . (2 . ƒ»� � Cli gmMm. It 7 . yg (a ! .kB8A f � §:§§; «#�■�� \�{$! �� .■■■■!• k|!£E ., ,;2■■| §..1,.|■!|■! s •a | e2■§e■ ■ �lE ■§�;§§ ! |f \ y.■■e. |�° .�e ;■■■■;� � : k .{ k . � � �k . � . s . } � �e ). (k / §. |!.: £. ° § | | E s � .�. . § 2) B . . §} . &' . � . � 2 . °q E § . ;2■; 7, f _ �!!E | ■■■§«! ■■_■;: | f#� § = f & �``®■■ k»fEE .ire .$ y#«! �■a■e■ Is■«|n■ § E !|!|| a^ ` d■,- «!�F d z „3,■■ .' | | � . . q � JR Engineering 2620 E. Pmspod RO., $te. 190 Fan COW, 00=525 RATIONAL METHOD PEAK RUNOFF (City of Fort Collins, 2-Yr Stone) LOCATION: NIX FARM NATURAL AREAS FACILITY PROJECT NO: 3902317 COMPUTATIONS BY: B. STRAND DATE: 5125/01 2yrsfonn, C/= 1.00 DIRECT RUNOFF CARRYOVER TOTAL REMARKS — Design Trbutwy 31N Paint A _ W CC7 tc (rrSN I Cmmr) 0(21 tm O(2) Daslpn (de) . P06 (ds) 0(2pet We) 2 102 0.38 ' F25 its 1 209 ORo 0.20 . 3 103 122 0.40 127 - 21i 1.21 121 4 104 0.71 0.38 ta.s 212 0.s4 .0.54 105 437 F20 16.7 . 182 1.87 1.87 loll 1.34 0.28 12.5 25 O.rl 0.71 7 107 1.31 0.20 73.1 1A8 OAe 0A9 Q=GCiA 9a2723110w.sls 0 = peak discharge (ds) C = runoff coefficient Cr=frequanayadjuslmentfades I = rainfall kdensily (fn/hr) from City of Fort Collins IDF curve (4/16199) A - drainage area (acres) 1. 24221 1(10t 6;f11O JR£nginsering 2820 E. P=P= Rd.. Ste. 190 Fad Coom CO som RATIONAL METHOD PEAK RUNOFF (City of Fort Collins,l0•Yr Storm) LOCATION: NIX FARM NATURAL AREAS FACILITY PROJECT NO: 39023.27 COMPUTAIIONS BY: H. STRAND DATE-- 5n510I. f0 yr dorm, Cf = 1.00 DIRECT RUNOFF iCARRYOVER TOTAL MIgn Point TIw19ry SUbbMIn A CC1 (a0) tc (mN) I O(ID) 0*11 (ofs) k0m Dash„ Palm 0(10) 060-50t We) (cts) .. - 0.25 122 0.19 11.6 127 357 0.34 M 2.07 0,34 207 M310.38 071pgp {97 020 157 3.11 2.D81.3{ 0.28 125 3.{7132 i,g1.31 0.3D 10.1 3.17 OR{ O=C,CIA 9D2M31bw.W O = Peak discharge (ds) C = runoff ooeflldent C1= frequency adjustment factor I = rairdaif intensity (inAx) from Chy of Fort Col ins OF curve (M16M) A= drainagearea(acres) 1•41.441p0+tcfa JR Engineering 250) E Awyed Rd.. t. 760 Fart C*MP0. CO e0525 RATIONAL METHOD PEAK RUNOFF (City of Fort Collins,100-Yr Storm) LOCA71ON: NIX FARM NATURAL AREAS FACILITY PROJECT NO: 39023.27 COMPUPATiONS BY: B. STRAND DATE: 525/01 100yrsrorm, Cf= 1.25 DIRECT RUMOFF . CARRY OVER rrOTAL REWUUM Des. AM Point Dear. A (00 C cf k Or7N i O (100) 00 (da) from DaSW PdM O (10D) (de) 6(f00Rat (ds) 2 102 0.33 0.31 11.6 7.2D 046 0.0 3 IN 1.22 0.62 12.7 7.02 6.2s S.3 4 104 0.71 D.44 6A 6.31 2A3 26 105 4.57 035 15.7 8.X 7.20 7,3 td6 1.34 O.A1 12S 7.M a10' at 7 107 1.37 073 16.7 6.48 2.13 21 Q=CIA 602723MW-Ift Q = peak discharge (cfs) C = runoff cceffiderd i = rainfall intensity Onlhr) from City of Fort Collins OF curve (4116f99) A= drainage area (acres) 1.64.6621(10FOcfm 1 ' 1 ' Design Procedure Forrn: Extended Detention Basin (EDB) - Sedimentation Facility ' WATER QUALITY POND ProjectNmm: NIX FARM NATURAL AREAS FACILITY ' Project Nkmhber. 39023.27 CeOW11111r• m Entidneving 1 Designer. S. STRAND ' Dare: 6/3/01 1. Basin Storage volume ' ' A) Tributary Area's Imperviousness Ratio (i moo) 6 = I= 19 % 0.19 ' B)Comribubng Watershed Area (Area) A= &17 acres C) Water Quality caphme volume (wacv) WOCV = 0.11 watershed Inches ' ' (WOCV=IA•(0.91&P-1.19*F4 U.70) D) Design Vdume: Vd-WQCV/12 • Area • 12 Vol. = 0.07 soft 2. Outlet Works ' ' A) Outlet Type (Cheek One) x Orifice Plate . Perforated Riser Pipe - ' ' B) Depot at Outlet Above L.Orevat Perforations (H) H = 2 ftOt her ,C) Requked Maziumum Outlet Area per Row, (Ao) Ao - 0.19square inches ' (Figure F-0B3). D) Perforation Dimensions (erxer one only) _ i) Circular Perforation Disinter OR D a 114 inches, OR 6) r Haight Rectangular Perforation Width W r inches E) Number of Columns (M See Table 6a•1 for Maximum) no = 3 number F) Actual Design Outlet Area per Raw (Act A, = 0.15 square inches G) Number of Rows (rtr) - nr = 3 number tQ TOW Outlet Area BbJ A= = 0.45 . square inches 3. Trash Rack A) Needed Open Area - At = 0.5 - (Figure 7 Value) - AN Aj = B) Type Outlet 15.3' square inches of Opening (Check One) x 5 2' Diameter Round . 2' High Rectanoulac C) For 2'; O Smaller, Round Omeninn (Ref: Figure Ba) Other. . ' 9 Width ofTrash Rack and Concrete Opening (W. W—= 9 inches . - from Table 68.1 fi) Haight of Trash Rack Screen (Hm) Hm = 22 inches ' = H- 2' for range of top support ' ti) Type of Screen Based on_Depth H) x S.S. f193 VE Wire (US Fast) . Describe VoW Other M Saw Opentrg Slot Dhmenslon. x 0.139- (US Me.r) . Describe IMMef Ogg. ' v)Spacing ofSupport Rod (D.C.) 3/4 hntlnas 1 ' Type and Stoe of Support rod (Rd: Table 6a2) #158 VEE Page 1 vi) Type and sae of Holding Frame (Rel. Table 684) 9/S' x 1.0' flat Oar D) For 2' High Rer3annular Ooenine (Refer to Figure aby l) Width of rectangular Opening (N) W = mares 07 Width of Perforated Plate Opening (WoDnc=W+12') W. r = inches AI) Width of Trashmck Opening (Nopenirg) Wcs.ri, = Inches from Table Sb1 Iv) Height of Trash Rack Steen (Hre) Hm = Inches v) Type of Screen (based on Detph H) Klemp'� KPP Series Aluminum (Describe If 'other) Other. vi) Cross -bar Spacing (Based on Table SM. KlempTM KPP inches Grating). Describe Vahan Other: vti) Minimum Bracing Bar Size QQempTM Series, Table 6b 2) (Based on depth of WOW surcharge) 4. Detention Basin length to width ratio 2 (LNV) S. Pro -sedimentation Forebay Basin -Enter design valuae A) Volume (5 to 10% of the Design Volume in 10) 0 acre-feet B) Surface Area acres C) Connector Pipe Diameter ids (Size to drain tills volume in 5-minutes under inlet control) D) PavedMard Bottom and Sides gy p 6. TwoStaga Design A) Top Stage (D Q = Z minumum) Dwo = 2 feet B) Bottom Stage As - Do + Is min, Dec + wr may Storage - 5%to 15%Of Total WON C) Micro Pod (Minimum Depth = the Larger of - 0.4ToP Stage Depth or 2.5 tieel) D) Total Volume: Valk„ = Suxage from 5A+ 6A+eB Must ba- Design Volume in 1D 7. Basin Side Slopes (24 horizontal distance par unit vertical) Minimum Z = 4, flatter preferred B. Dam Embanlm ent Side Slopes (7, horizontal distance per unit ver Minimum Z = 4, flatter preferred B. Vegetation (Check the method or describe "other") Siorega= . ace -(eat Des= 2 feet Storage. 0.1 saedeet Surt. Area - 0.11 acres Depth =. 0 feet Storage = ace -feet Surf. Area =. acres Vole= 0.1 acre-feet Z= ..4 (tnwirontoWerftl) Z=. 4 (limimntaWardcal) . x Native Grass Irrigation Turf Grass Olney. DRAINAGE CRITERIA MANUAL (V.3) STRUCTURAL BEST MANAGEMENT PRACTICES 1 0.6C 0.40 Io 9 020 v.gu u.ou 1.0 Area per Row,a (in 2 ) FIGURE EDB.3 Water Quality Outlet Sizing: Dry Extended Detention Basin. With a 404iour Drain 71me of the Capture Volume Man .A -a liv ._ ^---_ - - 'J -�_ _ r \\ ,' 1. ♦ © 1 nt (.' i f .i gii I• s ,,. ' �``� •1 .; 1_ _-_'-_••__• Wa AID .TV v+Yila • � f1 -:in _: , �) p / `�J ��~ _ / ` Pr5•Y . ; I � A'vs,oM,wwaamr ' �/�.`,'11 �. f^.lj :., . I. r' B 1' ".ram 1 emuR•IN.O ovw ,•5' f yy%�1'_J. �c: U' 8 Ah '� = �•��! c- �.�tfto '` 5"* 0.4- . _- \ � :"`� . � ..... � '' .w \\ ` ♦ : 1 ICI covaav]r SEE 6i9•ET A OF A " ''. !1 AN[F of AN¢s it I I I I I. SWALE SUMMARY TABLE SWALE O CFS 0 FT. V FT/S 5 SIDE SLOPES A -A 2.6 0.5 2.4 1.5 4:1 8-6 5.3 0.6 2.3 1.0 6:1 C-C 13.4 0.7 2.5 ' : 4.0 10:1 0-D 13.4 0.7 2.9 1.5 10:.1 E-E 16.5 1.1 3.6 1.3 4:1 F-f - 2.1 0.4 2.8 2.6 4:1 G-G 5.3' 0.5 4.6 8.7 4:1 DRAINAGE SUMMARY TABLE Oul • T101Y1u Aq• C ]I C 100 .01 le fa0 O UI O Iy01a ••NS .a AY YM d.l sr. ] 102 ;)f 02. 11a Ili 0: y 10 e. SY I" on ]e 9 • f t. 05 . 155 e51 125 a 15i 1$I 1., ]] I" 1-1 0 A f 125 4,, .l r a zs 3 s 1a-11]1D1 en 51, 132 15.1 a 1N a 10 dA111 Isl 2 1 nI 21. Is> 1IOIR la Il»Ip.pA4ODNl MMAS nN5[ fi! Mn3 dl rre IP! d M wOfOM MqO RM IR FMW IY.1114 N[K rdM. 1. Or1' d ,R1 ml[ mMAIIT VOIIY P(Y10R •dRlp♦ Nr Z,Ol3aa 1i VYr N IIaIIS allot r0 qr O)M1DCICMF A'D6 f4 .¢ r®® aA[IrA Yf IAeo 9ALL K Y]Wlm arAl b Nn WO RIUOK KOm eri.tf elC. Ml OMO1 IILYAm qmA 0rq IRA9a,L5 f4,1 R t e< aawww.' rt it ttlrc mdmnu mA¢ K wu+m r It rwwm aMDMer>ordYlc mMAYpo. are Y•.evwal oarm bYL lRia3MA.tQ KQTgdI f KW A pIMY,¢ d m]iM tRiAI VM •r lWl6 m Aa qL. APN¢ ra Yl[aMK W,6ACbf yW MMl YO lO M D,411FSr Matt• .0.m d 1•( u uta mvo vm 1ab 01MRlG atam (1lbaYv, 0vA4 uMm YN•4taA alb41O 011olINIY ry�,µq Ki{rAM�Ot 0 OD . W OrYDArn Of11R O WIIYI[o b lot[ Y rfq ara amrer m¢T s0113 d aT O,fLL tbII1 D0Nr0 n lab vents• aeon aol ll]K Mw wlll mJ YR bdi Il[Oallm 1p/q..T M ,WMo\1 W!A MM Ro am(1•Ava IMao:fatc Ln) a YmA1I]n IAAm o11aNs rfYttm n K a1AArm YtV I,o biml oqL A.tl.O NA YWpoeo K Yl rlWi Paoo 0MaC1b, KIA10 N K 1y llelmw..o-egvD aoaaM ra. ue AAAAe .dAm Ave. r rm.¢r eualrb Ma navte over a•Me1y .Ngavr +sans q %¢�O n 4 vm d NT dLlb Dlidbo lOMna),L all 1l]vaeaNr lanYOaaO m09m1 m1L10. Abed sw. v rlrlma re Ivi.m a :afAR1LLt0 q :N MA etll b,dr C4i Y 11iCt W .OR M>p f WOYOY d va rlmem rantw u Argm mnla v.:rYAtaav MIDII s .N1m bv.v Da•m ylau v Im¢1v Ab YOATDO v Y A cwa M tme a K ,q b OrrY; 1fr IrO4Q Mlo aM. n1fYIQYgry Ayt.� 11 •lr� � N.l4 NWOr1 MRAl Y�O IW�OUn'1(Tl.pq�b SRdq[ aW.bY MIW b WR AML Z 15® Mo VAa•@ ,•" j rn •love twsn 1lM numA• Oep••10 d OdtAMo v Ss1 n as ova 1,•10tµ i am ad tm¢n n a INaY aw b•oc ar. tYAwbn mevKD Nan2ua rxw v vnb sm•¢1 n ne mNwna ..t'q,a AA•i 0..t.Y Yugw LprA A. Qym • 9 1 3 •If -e. i v.w .A.1Y.. Imm ..A.rbs emem •AY� � IO�..wEA en va+l n.AAnm•,meura. 1 IOotN A101 M 316r O/EnVa d � r r � OA9N 9alYOrAr _____- ENS1Ne RNFS sv� NR�OSO OIIEi AM M �. RAgD FIN 9[OIIOII • 9 tx CAa e0-%, 0 mom pA{[5 OpoPf)5'E9 OMET LOCATION • - EN9RN0 3' O]MOIA pyt,1,1011 Cb1r011! PRO`ORO T fA]N1]NIR ' vgovOYD r LOIIgp v 41-n- ar IExfE OIIMFr Pft=TM ® CON9rR11CIlON ENIRANLL ® wmN ? 1RN NIFOINN of ROM of Fort Co ILITy PLAN W. •.,. • rrl�. uN+v 9r:a r BY: A.0 er 3 i C m.5 C r�S®off s UT 10 a 19 - bP - 9023-27 C-3 1R'a I 11 I I G I i I I 1 I 11 I rah I I roh \ `•�„`` : p4wOO11 aw nwa 1 \ faRbG9el CHIICIA \ ��.t`� y �. ._ ID ','lr' \ ��:. 1 tt "•-\ \I t�•1 •fib^� \ it 1 1 O OF 10 ]0 ]! 0 s0 100 YnOL �.1L Wm w. ��4 46G OM LEG M0 Qmm PCMi elan LaapaA . a Ialxafl mvruxr . MQA M .1QE5 , r� MI � I� MSTI M,NOM,• .��. asorosTn ancr w,o we RAWZD DID MMTM ®�1, taoaoP awes I� �M IIl�MOAYGMO YrN kAw L[ 9Rw In Ia0 Vf O K 4gtu[ I1M ra IIIY Mlaat /Ilrp rblA. r ` P e 9 i — — — cRsrala r mlroua s ; 3 � E —"--- narelc r mlraa Mlm D s oorrmw rawoSm r camw O z : 1F sLr COsalwl m mm+na waanm usq K wm vaOmv w City a fcwt CM11ML Cokm ft UM Y PLAN APPROVAL z a( J ® smuclr mw Aoaao\tu� 4 s -1 K N W mKerlpa a now _ oy ot. o.. awolm er w A � = W-W Q z x a < $ . w.. own¢a ew ca . it M 19 smi OEOZp 95 Ilo 11O2JR7 tea.'— ata C=3 189L Alt u fff// ���:�. Ix � 1`l100 ,toll " deal Lori AAW"FACALIl vp —^ • — a�'w3^I real .tee .ter X. ACaas W ACd ♦'' �\ RD all gallnNnllN IF ♦ �\! \ \ N ON 103 MF MIF ` Jae • 1.22 0.66 i Oy 1 h 1-1T1"777 _ 103 / /1! �IBI- f A•bl AI1Q I \ �Il I_ q_�113R QfIFALL �/� CONSTRUCTION SEQUENCE MOl m 17"12-T 1 2 3 a s B 1 B I3.mdnMn GI.dNd and Notion c"l Sal Roughing PeMnYerBaMer AddlAI Bal Vegelytn mCN Sol Sealant Met NIINII NeYen CmYM a.uun.al: Sedmeit TnyBeln Wad FIbn 131eM Imp Slit Fenn By m Send eeg. Ben Sol PnpmNm Contour Fwmvn Tonal AephdVConnb PMrp Da.. Vilinta : P*rnwnent Se PWmVg MulehngiNalanl TamPenN Seed Plntlng Sm MebIINM NMnnP/Mmealia eb wn.r BULDNOCOISTNUCttN1 tY wall V4. 1.22 0.62 aminia • -I I I N 0.360.5B�\ •\\, (` \ T 011 102 I ; Will \ // / / I III I \\\\\\\\\♦,\ / \ I11 1 1 ?.36 0.31 1 \\^/{]1 \ xx ix � IF \ v i f t4L57f025= \ / Ilil \\\ I\ I \IN \\\\\ \\ MaM Mull \\ \\\♦\ \ // „/ 111 •I ��� � � ��♦ \,I\\ I I \�\\\\ _ \\\\I�I I I II i11 I�I OVERALL DRAINAGE SUMMARY TABLE \ I I \ \\ \ \ / /�- ""'� I / „• I 1 I \\ -- Nean TrMIF Ares amC11ep1 Te1B Initial g311d gtmlbAll than L Feel enlwy b nn d. l de z Ion aM amaanllieIta RA3 NOTES: T EDISNRBEDARBAISt GS1 MIACREMD DOES NOT RECUIR E A STATE OF COLOMDO DIECIIARGEPERMMBI/TTXECON TORSHALL APPROACXTXEPROIEC )NTI `III E STANDARDMETNODS. ALL UTILITY NOIIFlCATINJ CENTEIg DF caoRADo 811 • C jSR g-mmESS DAYS IN ADVANCE I \ ppZ YW Diq SEEN, M EXCAVATE \ FOR mE MARKING OF UxES "D \ mum uIll GGVGa�Y EpSTNG MINORCONfOI1P ERISIING MAItM CONTOUR PROPoSEO MINOR CON R PROPOSED MAJOR CONTWR PROOESED DIRECTION OF OVERL NUFLOW OMINAGE BASIN DNIDE LINE STORM RUNOFF COEFFICIENT GEBASNARSA QW ¢Z Z In W 1 LL t � Op-N he 6 O zm �0N U Zgu 1 1`x in 8 30 13 D 30' SO m m A I aa SCALE: 11,e 30' O O 0 C CITY OF Fl)RT COLLIll COLMADO UTILITY PLAN APPROVAL APPROVED qrr warm CHECKED BY: wA1w Y wEsgwATm ualrr CHECKED BY: SIOUNAM Ul1UW CHECKED BY: PNIKS . maumdx CHECKED BY: moot w m CHECKED BY: NANRAL KE RCM I'l NO. 11 a801 ]A I _y