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HomeMy WebLinkAboutDrainage Reports - 07/19/2016/ DRAINAGE REPORT FOR 1112 BIRCH STREET PARKING LOT, CITY OF FORT COLLINS, LARIMER COUNTY, COLORADO P No Text I ' November 23, 2015 ' Mr. Shane Boyle City of Fort Collins Utilities — Stormwater 700 Wood Street ' Fort Collins, Colorado 80522 RE: Drainage Report for 1112 Birch Street Parking Lot, Fort Collins, Colorado ' CDS Project No. 15-7510 Dear Shane, We are pleased to present to you the Drainage Report for 1112 Birch Street Parking Lot. ' This project will produce parking lot on the west side of the lot. A pervious interlocking concrete pavement system is planned for this parking area. ' The design complies with the latest revisions of the Urban Storm Drainage Criteria Manual (Urban Drainage and Flood Control District, Denver, Colorado) and the ' City of Fort Collins Amendments to the Urban Drainage and Flood Control District Criteria Manual. ' If you have any questions or need additional information, please do not hesitate to contact me. ' Sincerely, RE... FOR AND ON BEHALF OF p� T� CD NGINEERING CORPORATION 0 �•N3 6 &k ' ; •�� Suzette L. Schaff, P.E. 1 165 2nd Street S.W. • Loveland, CO 80537 • (970) 667-8010 • Fax (970) 667-8024 • www.cds-eng.net TABLE OF CONTENTS Paoe Letter of Transmittal- ' i ' Table of Contents Report Certification iii General Location and Description 1 - . Location , .. 1 Description of Property 1 Drainage Basins and Sub -Basins 2 Major Basin Description 2 'Sub -Basin Description : 2: .. Drainage Facility Design .. 3 General Concept 3 Stormwater Quality 5 - Four -Step Process 5 Design :Methods 5 . Conclusion: 6 References Exhibits Appendix i - I I hereby certify that this report for the final drainage design of 1112 Birch Street Parking Lot was prepared by me (or under my direct supervision) in accordance with the provisions of the City of Fort Collins Amendments to the Urban Drainage and Flood Control District Criteria Manual for the owners thereof. 1 Suzette L. Schaff - Registered Professional Engineer State Colorado No. 35692 1 n Drainage Report for 1112 Birch Street Parking Lot Fort Collinq, Colorado , General Location and Description Location The 1112 Birch Street Parking Lot is proposed improvement; located at an , existing Sorority House on Lot 6, Johnson Addition. The property is located in the northeast quarter of Section 16, Township 7 North, Range 69 West of the Sixth Principal Meridian in the City of Fort Collins, Colorado. More specifically, the site lies on the . north side of Birch Street, approximately 550 feet west of Shields Street. Medium . Density Mixed Use lots lie to the south and east of the site. The lot to the east is currently vacant. Low Density Residential lots lie to the north and west of the property. Please refer. to Exhibit A for a vicinity map that locates the property. Description of Property In the existing condition, the 1.18-acre project site contains a sorority residence, asphalt parking lot on the east side, and landscaping that consists of grass,'shrubs, mulch, rock and trees. The land slopes to the south and east at slopes averaging 2%. In the developed condition, the site will include all existing features as well as the new improvements. The improvements for 1112 Birch Street Parking Lot include the construction of a permeable interlocking. concrete paver (PICP) parking lot, a sidewalk between the parking lot and existing building, a drainage system of piping and trickle channels to drain the stormwater, and perimeter landscaping around the parking lot . The underdrain system carries water from the parking lot around the north and east boundary to the North gutter of Birch Street. The classified soil on thissite is Nunn Clay Loam, 1 to 3 percent slopes (Map Unit 74),.which is1n the.hydrologic group, C, which would -indicate a well -draining soil with high runoff potential: . .1 . .1 Drainage Basins and Sub -Basins Major'Basin Description The City of Fort Collins Master Drainage Plan hasbeen referenced to identify the . prepared stormwater drainage design for the major basin Jn which the project site lies.. The property lies within the Old Town Basin, in which storm water is directed through the city storm sewer system that outfalls to the Poudre :River. The City of Fort Collins has restricted stormwater release .to consider water quality and historic runoff rates. Minor storms are released at a controlled rate in order to filter sedimentation and pollution from the runoff before it is released from the site. Stormwater from major events must be released at 2-year historic runoff rates. The area of the Old Town Basin which contains this project site does not contain a storm sewer system. Stormwater is released to the surface and into the street gutter system. Eventually, the water drains to streets.that contain storm sewers that outfall to the Poudre River. Sub -Basin Description Existing slopes direct stormwater runoff south and east and culminate at the Birch Street gutter at the southeast corner of the property. This point is labeled Concentration Point 1 (CP1) and is used to compare existing and: developed runoff coefficient.and imperviousness ratio. The only off -site flows that enter the property are generated from the west from the rear -lots of neighboring single family homes. Off-site- stormwater enters the site from the north and west areas of the proposed parking lot and is filtered through on -site landscaping to reduce sedimentation onto.the site. Additionally,. existing fences on the property lines filter large debris before it enters the property. Estimates ofthe2-year and 100-.year off -site runoff rates. demonstrate that those flows are minimal. Off -site flows are allowed to leave the site undetained if the paving system will not take any additional flows. In the developed condition,.the.1.18-acre site is divided into two sub -basins. The overall runoff, coefficient for the. existing site conditions is 0.49. The developed runoff coefficient for the entire site is 0.60.: Sub -basin S1, contains 0.34 acres and encompasses much of the west portion of the site. This basin contains the proposed parking lot, the northwest quarter of the 2 existing building roof, and most of the proposed sidewalk between.the.lot and the existing building. The outfall of the.PICP sub base is located at the northeast end of the parking lot, where the runoff enters a six-inch Polyvinyl Chloride (PVC) pipe that carries ' water along the north and east boundaries. The pipe daylights to a two -foot concrete valley pan that leads to a sidewalk chase on the north side of Birch Street. Should the sub -base of the PICP system become loaded, the outfall of the basin ground surface is located at the south end of the lot, at the connection to the concrete driveway access. ' This is the outfall considered. for the sub -basin flow values, since the time of concentration through the six-inch solid pipe is minimal. In the existing condition, the runoff coefficient is 0.22 and the resulting 2-year runoff rate is approximately 0.20 cubic feet per second (cfs) and the 100-year runoff rate is about 0.70 cfs. In the developed condition, the impervious area increases within this basin. The runoff coefficient of the basin is 0.53 and the 2-year and 100-year runoff rates are -about 0.40 cfs and 1.70 cfs, ' respectively. Sub -basin S2, with 0.83 acres, drains the south and east section of the site to the ' north gutter of Birch Street. The basin contains about three quarters of the roof area,. .the existing parking lot and bicycle pavilion and 244 square feet of proposed sidewalk. ' In the existing condition, the majority of.the structures are in place except for the proposed sidewalk. The runoff coefficient is 0.62 and the resulting 2-year runoff rate is . approximately 1.10 cubic feet per second (cfs) and the 100-year runoff rate is about 5.30.cfs. In the proposed condition, the proposed sidewalk is included, which results in ' a runoff coefficient of.0.61 Subsequently, the 2-year storm event produces,a rate of . approximately 1.10 cfs and the 100-year event generates about 5.30 cfs. .. Drainage Facility Design ' General Concept The design concePt.for.1112 Birch Street Parking Lot is to develop PICP parking ' lot and pipe outlet along the north and east boundaries of the property: Landscaping is placed along the west and north boundaryof the parking lot. All. other, landscaping and - structures will remain in place. The pervious pavement and new landscaping will provide water quality. 3. The parking lot is constructed of a PICP system that includes pavers on.the surface of the lot and a bedding system that contains three layers of various sized_ granular material. The 3 1/8" thick interlocking pavers are placed on top of a two-inch, layer of #8 crushed rock. Under this layer, four inches of #57 rock is placed. Both of these layers provide stability to the pavers while filtering pollutants and fine. particles from the stormwater. The lowest layer, which consists of a twelve -inch sub -base of #2 rock, detains runoff as it enters a six-inch diameter perforated pipe. On the surface.of the parking lot, the parking spaces are graded to slope toward the drive aisle. A minimum 30-mil HDPE impervious membrane is placed between the sub. -base and subgrade at the parking stalls closest to the building to protect the foundation from water damage. Due to the limited vertical distance between the building's top of foundation and the surrounding yard, the drive aisle and perforate pipe, is set at a.flat slope. In the event that the PICP system cannot take additional stormwater flows, a surface overflow is provided at the street entrance to the parking lot. The perforated pipe sends flows north and then east through the parking lot. At the northeast end, the pipe is transitioned to a six-inch diameter solid wall PVC pipe which is installed at a 0.40% slope. The solid pipe continues along the north and east boundaries and daylights 75 feet.north of the Birch Street 'sidewalk. A concrete headwall with a steel. orifice plate is set at the end of the pipe to restrict flows to the two-year historic release rate for Sub -basin S1, 0.20 cfs. Stormwater then travels via a two -foot wide valley pan to a two -foot wide sidewalk chase that.releases flows to thenorthgutter of Birch Street. The detained water willbe stored in the granular sub -base of the PICP system. The allowable storage volume is equal to 30% of the volume of this base. The volume of the base is 9;844 cubic feet. The resulting available volume is 2,707 cubic feet as calculated in the spreadsheet "Design Procedure Form: Permeable Pavement Systems (PPS)" (please refer to the appendix for this spreadsheet). The required detention pond volume is 1,882.2 cubic feet. There is sufficient volume within the PICP sub-base:to. hold the developed flows. Stormwater Quality Four Step Process The Four Step Process is a method hat is used to reduce the negative impact of urban development upon receiving waters. Descriptions of how each step .will be implemented with this development areas follows: - 1. Employ Runoff Reduction Practices a. Two Low -Impact Development (LID) measures will be used in this ' project. The construction of the PICP system.in the proposed parking lot will reduce developed runoff to near -existing levels, thus minimizing tthe additional load on the city storm sewer system. Landscaping will provide water quality which will facilitate the reduction of sedimentation and erosion control onto downstream properties. 2. Implement BMPs That Provide a Water Quality Capture. Volume (WQCV) with Slow Release a. The PICP system will employ a restrictor at the downstream end of the perforated underdrain to limit flows to a two-year historic rate, thus reducing the impact of developed flows into the city storm sewer system. The PICP filters impurities'from the runoff, resulting in clean ' water leaving the site. ' 3. Stabilize Drainageways a. No drainageways are located within the near vicinity of the ' property. However, the water quality measures implemented in this design will benefit receiving waters. 4. Implement Site Specific and Other Source Control BMPs a. The PICP and landscape features on this property will provide water . ' quality to reduce sedimentation in downstream storm sewer facilities and drainageways. ' . Design Methods ' Worksheets are presented in the appendix of this report to show the methods and data used to design the'project site. Most of these worksheets come from s worksheet programs` supplied by the Urban Storm.Drainage .0rite na-Manual. Other worksheets are provided by the design engineer, using techniques recommended in the Urban.Storm Drainage Criteria Manual (USDCM) and the City of Fort Collins , Amendments to the Urban Drainage and Flood Control District Criteria Manual . The runoff coefficient of each drainage basin is determined by finding the weighted average* ' of various. impervious areas within each sub -basin. The hydrological data is calculated; using the rational method. Required' detention volumes are analyzed by the FAA - method. Orifice worksheets provided in the USDCM.are utilized to compute the necessary orifice areas of the underdrain pipe restrictor. Conclusion The project design for the 1112 Birch Street Parking Lot is completed in compliance with the Urban Storm Drainage Criteria Manual and the City of Fort Collins Amendment to the Urban Drainage. and Flood Control District Criteria Manuals. - The proposed improvements are designed to direct stormwater to the street via a . ' PICP parking lot and underdrain system that restricts runoff to a two-year historic rate. The Four Step Process will be utilized to ensure that water quality is provided ' prior to stormwater leaving the property. . 1 1 s References Urban Storm Drainage Criteria Manual, Volumes 1, 2 and 3 (June 2001 and November 2010, Urban Drainage and Flood Control District, Denver, Colorado) City of Fort Collins Amendment to the Urban Drainage and Flood Control District Criteria Manuals (December 2011, Fort Collins, Colorado) ' National Resources Conservation Service website, . http://w6bsoilsurvey.nres.usda.gpv/app/Web8oilSurvey.aspx No Text No Text Ail .vy�i r f EXHIBIT A: VICINITY MAP cm Engineering Corporation 165 2nd St. S.W. Loveland, CO 80537 10 Tele: (970) 667-8010 FD w 9. No.: Project: '2 BIRCH STREET PARKING LOT FORT COLLINS, COLORADO 5c, Project N — EXHIBIT B: DEVELOPED BASINS 141 Engineering Corporation 165 2nd St. S.W. Loveland, CO 80537 11 Tele: (970) 667-8010 FDwg. No.: No Text RUNOFF COEFFICIENTS & % IMPERVIOUS - - LOCATION: - 1112 Birch Street • . - _ PROJECT NO: P15-7510 ' - COMPUTATIONS BY: SLS- DATE _ - 10127/2015 Recommended Runoff Coefficients from Table RO-11 of City of Fort Collins Stormwater Code, Volume 1 - - Recommended %Impervious from Table f203 Urban. Storm Drainage Criteria Manual, Volume l - 4 Type B Soils - - Streets, parking lots (asphalt): Sidewalks (concrete): Roofs: Pavers: - Landscape Areas (Average, Sandy) : Landscape Areas (Steep, Sandy) Runoff % coefficient Impervious C 0.95 100 0.95 96 0.95 90' 0.50 40 0.15 0 0.20 0 SUSSASIN DESIGNATION AREA.AREA (ec.) .(WA) TOTALE51.200 ROOF PAVED ..AREA (sO.R) PAVERS AREA (w.R) SIDEWALK - AREA (W-b LANDSCAPE AREA (sR.R) RUNOFF COEFF. (C) % Impervious - REMARKS . Er s' Lot 1.18 7.147 10.454 0 4,356 29.243 OA9 41 Pm e6 Lot 1.16 7.147 10,454 10.019 6.534 17.045 0.60 53 RUNOFF COEFFICIENTS & %YMPERVIOUS LOCATION: - 1112 Birch Street - - - PROJECT NO: P15-7510- - ' COMPUTATIONS BY: SLS DATE: 102712015 Recommended Runoff Coefficients from Table RO-11 of City of Fort Collins Stormwater Code, Volumes Recommended %.Impervious from Table RO-3 Urban Storm Drainage Criteria Manual, Volume I Type B Soils '. Streets, parking lots (asphalt): Sidewalks (concrete): ' Roofs: Gravel or Pavers: Landscape Areas (Flat, Sandy) Landscape Areas (Steep, Sandy) Runoff - % coefficient_ Impervious C 0.95 100 0.95 96 0.95 90 0.50 AD 0.15 0 0.20 0 SUBBASIN DESIGNATION - TOTK AREA (°o.) _ TOTAL AREA Is�.ftl ROOF AREA (.Q.n) PAVED AREA - (N.ft)' PAVERS .AREA isaft)' SIDEWALK AREA (.q.ftl LANDSCAPE AREA (sgft) RUNOFF 'COEFF. (C) '% IrtWM. -' -REMARKS S+-E o.a 14,913 1.307 0 0 0 13,600 '0.22 8 EXISTING FLOWS S2-E on 3e.2e7 5.8do 10.4ed 0 d. Pa3 15.010 0.62 56 EXISTING FLOWS S1-D 0.x 14,913 1.307 0 M m 1,307' 2280 0.53 a DEVELOPED FLOWS Sz-D on W.2e7 5.840 10.454 0 5,227 14.7W 0.62 57 DEVELOPED FLOWS os+ o.n <.792 930 0 0 0 3.asz a.3+ 17 NORTH OFF -SITE FLOWS 0a2 020 8.533 1.803 0 0 61d 5.315 O.dS 1 WEST OFF -SITE FLOWS OS3 1 0.07 1 2,950 1 641 1 0 1 0 39e 1 1.910 0.43 1 33 1 WEST OFF -SITE FLOWS No Text G - R N Z _ O E N � i ¢ U o 2 LL- < O c N LU rt O U t F- LL r U m • a E J �acnCD u ' U _0 -, -ZH 0W� N: d� a ¢' w', a .:. O�. . N .a,� oowww Y Z_P:oo n) V) - w w LL LL LL WLn XX»000 wwwowo�33 N m N b b 0 0 J m Ih vi i[i Z E LL O! O O O mE m" WZ ¢ J N 7 N 7 x N N ow F u 7 7 6l N n 1n 0 {D N 11 N ' t7 N t7 '0 30 m CO 7 b a J W a J O V O< b m 2 2 N 'lV G tV N fV N tV x m o O CS6 H � j m b Fb1 O mo O O O (� o y W F 72 m� N a o � J L b C C n J H L A b N O 1A O " c of " r _ E OOOp Till N N N W V Z r c �o Q v W J J .r.. (J t7 N N N fD C) b N t0 Pl IA O f7 O F W O G O G G C G z_ F N N N M 0 ID 0 f7 0 aD 0 ci 0 0 O 0 ¢ v V Z y W W p'm N m ¢ N N N N N D w Z' Z m ¢ y 5'Z a j a o �m c m .y N c '.LL .. - U y O U- -. - N C .- U - �. 2 - L Y LL - O. N - .. orC N '. y E a N - M.0 � T if + . o O. .. E z c _. O� n E Q + y .. -..'O oowww zzILCL . 0 - a E' fn (n W JLLL%LL. w LL LL LL w xx»000 C - W W W W - m O) O ... O! N m N m N O m O Q O ' - a _ .. - m 'u J: C N o r OR m 7 O N LL e U Z_ O W .. LL- 2 e N O N N N N O = j LL� O � C a p 0 0 0 0 0 0 C) W Z U' O - _ W - N F - . m O m 0 0 0 - Z ch - O E L.iLL a 2 �mmmm`"an ¢O m F t _ - o NIL - j- - O c U ~ y ~ .... O h m m r r r in m p LL O N O.N N N Cf a N a) Z .c L Q' 0 N J L .. i :v o o c o oo o -. 'W mE it - O A w O c N C C it lI% _ - U NN�A ^ Fw. 00000 Oo -'e a Z f O N m ai m 6 N O II r-.. - �T. _v 6 0 0 6 0 0 0 0 0 O ... .. . J - - � L Z 0c G z Z Z �' -_. Z¢ v _ < 'G =. j. '. y ?r Z U 0004o .J c u w ° .. z L RATIONAL METHOD PEAK RUNOFF (City of Fort Collins, 2-Yr Storm). ' LOCATION: 1112 Birch Street PROJECT NO: P15-7510 - - - COMPUTATIONS BY: SLS - - - .' DATE: . '- 10/27/2015 . .:. 2 yr storm, Cf =.. 7.00 DIRECT RUNOFF CARRY OVER TOTAL REMARKS Trmutary Sub -basin A (ac) C Cf - tc (min) i (iMhr) 0 (2) - (ds) from Design Point 0 (2) (ds) 0(2)tot (ds) E S1-E 0.34 0.22 11.2 2.13 0.2 0.2 EXISTING S2-E 0:63 0.62 11.6 2.06 1.1 1.1 EXISTING S1-D 0.34 0.53 11.2 2.13 0.4 0.4 DEVELOPED - S2-D 0.63 0.62 .11,6 2.08 1.1 1.1 DEVELOPED OS1 0.11 0.31 7.5 2.47 0.1 0.1 N. OFF -SITE OS2 0.20 o.as s.o 2.65 0.3 0.3 W. OFF -SITE OS3 0.07 0.43 5.0 2.65 0.1 0.1 W. OFF -SITE . RATIONAL METHOD PEAK RUNOFF. (City of Fort Collins, 100-Yr Storm) ' LOCATION: 1112 Birch Street ' - PRO.TECTNO:--,P15-7510- COMPUTATIONSBY: SLS ' .DATE: ##t!##### 100 yr storm, Cf = 1.25 DIRECT RUNOFF CARRY OVER TOTAL REMARKS Des. Point Area Design. A - (Be) C Cf - tc (min) i - (irdhr) o (100) (ds) - from Design Point Q(too) Ids) O(1o0)tot (ds) S1-E 0.34 0.26 11.2 7.42 07 0.7 EXISTING S2-E 0.83 0.77 9.1 6.06 5.2 5.2 EXISTING - St-D 0.34 0.66 11.2 T 42 1.7 17 DEVELOPED S2-D 0.63 0.78 e.9 6.11 5.3 5.3 DEVELOPED 221 0:11 0.36 6.e 6.92 0.4 0.4 N. OFF -SITE osz 0.20 0.56 s.o 9.95 1.1 1.1 W. OFF -SITE OS3 0.07 0.54 5.0 1. 9.95 0.4 0.4 W. OFF -SITE No Text - - N 1 W Chs-N000.IM,cAOCACACOU)MN CO N'N CO M M.'7 '-T M RT M,M M CO M M 'IT= 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 O p Lls 0.0 0- 0 .0 O O 0.0 O 0. 0' 0 0 0 0 O F i . LU CO -N CO. CA ,U) O N N CO LO 'T 0) 00 U) N. U) N .. I,-TU)NI-OONO'N'rTOD0U)O co p T r r r T T r r T r T T T T r H - - - 0 0 0 0.0 O 0 0 '0 0 0 0.0 O 0 0 ' LU N N N N N N N N N N. N N N N N N w 2 P-� P-: t- r-� n t-� h r-_: t� '[� I� n MCANU.)0'TO(ONco'4000000:Nv C6 T�rNMMI;r V LOCOCOn00� O=O �. .. ..` M N fV:.- Lu O O 0.0 0 0 0 O O O O 0 O 0 O O 0 cc 00E- `o: z N, co r- co 0)`v c-'0 0.h O CO Lo V V M CO O Cp I`. CO CO (q U) U) U) U) U) U) U) U) U) E . . Ow 0UJ l 00 �r'00.00.0000000,0 1 D< pmo w LU CO V CO 0 1'-. N iT q O � CO T 0 .r- It II- 6 4 6 6 6 o) (6 c6 L6 4 cNi cj6N n4 N N N N N N N N N .N N V CO O O W N N N- N N N N N N N N N N N N N COCONN. O O T O CDW �� 0000000'000000000 w I U- w C ImoN co ') Lo. CO 0 00:O LO V CO M. M N .I W� ..Nc-r�.r00000000'000 v '. CA - . ..W �MMMMMMMMMM.MMC`')C`')MC`') y' Q @000000000000'0000 d or— OC 0 •- �w Coco cocflmcflmmcs;(omCD(ocoCD, CD = II c0 o CO0000'(4(O.(000OCOCOCOCOCOCO(O ` 0 ^ m0 — 000000,0000.000000 .. H (n U T'.. c w J c (J d NWfA L6 II O_.. V U-)NNONttMCOMNt�i�c6LoL) CA1�( 00r-NC17Mr.CA Nct.-N r+ >Q`. N .. . �-0 d �. } Q .. O y Z r (A t� CO U) CO M N N N m 0=Q t6. �0 a) w.� (D L LL m Q 0 0 0 0 0 0 0 0 0 ,O 0 0 0 0 0 O W.c00.00000'000000000 .. CD 00 �, Q' F- . E LAOU)OOO.00OO.O00000 T T N CO 11 U7 CO t- 00 O 0 N v CO 00 . No Text 1 5. Perimeter Banner chm. One A) Is a penmeter bamer provided on all sides of the , Q YES . pavement system? . - 0 NO . ' (Recommeded for PICP concrete grid pavement, or for any .. no -infiltration section.) - - - 23 7510-PICP, PPS 102mm, 344 PM . . - Design Procedure Form: Permeable Pavement Systems (PPS) - - ' - - sheet 2 of 2 ` . Designer. SUZETTE SCRAPE � Company: ' LDS ENGINEERING CORPORATION _ Date: October 28, 2015 Project: 1112 BIRCH STREET PARKING LOT • Location: - CHI OMEGA SORORITY, FORT COLLINS, COLORADO 6. Filter Material and Underdrain System A) Is the underdrain placed below a &inch thick layer of COOT Class C If ter material? . Q NO 0 NIA - B) Diameter of Slotted Pipe (slot dimensions per Table PPa2) Ohl One -. Q 4-mch 64 . C) Distance from the Lowest Elevation of Me Storage Volume y = O.d it ... - (i.e. the bottom of the base course to the center of the orifice) - r.,•:u..,: ..r...a- ran ..r a - 4c, Choose One Q YES N0. - Choose One . _ 0 Placed above • Placed atme the liner and below me uner a. outlet ' (Assumes each cell has sirrilararea, subgrade slope, and ]origin beineen lateral barriers (unless subgrade is flat). Calculate cells _ individually where this varies.) A) Depth of WOCV in the Reservoir . Dw= ' 0.75 inches .. - ' (Fjevabon of the Flood Control Outlet) .. - B) Diameter of Orifice for 12-hour Drain Time - Do su, = - DA3 inches (Use a minimum orifice diameter of 318-inches) Notes. No Text ' CIRCULAR CONDUIT FLOW (Normal & Critical Depth Computation) ' Project: PARKING LOT AT 1112 BIRCH STREET Pipe ID: 6" SOLID PVC Tc y U y ORIFICE SIZE ' FOR ORIFICE AT HEADWALL :ON END OF 6" SOLID PVC 1112 BIRCH STREET PARKING LOT . NOVEMBER 10,.2015 a , ' PREPARED'BY: SLS AUTODESK Orifice Calculator ' Given Input Data: ' Solving for ..................... Area or Diameter Flowrate ......................... 0:2000 cfs Coefficient ..................... 0.6200 ' Headwater ....................... 0.5000'ft Tailwater 0.1700 ft ....................... ' Computed Results: Diameter ........................ 3.5826 in Velocity ........................ 2.8570 fps 1 _ . 27' p ®I✓ I Id �.. . e ols �A� � LOHRt EIECdIC59ry1LFA5NB£SSNY — �TBWYNBAxFW.IRFD YERd:LL06EANLE �I r 51� \m.mw WWaaIM + J / d r / ��la -- {.a �y" waaooEa IaN I OS] J �' I EN4IBIOMIIBIM — — I � — F\ TW.TNMMe `— r� rorare BYW3NWE� BIRCH STREET \ _ —98—BB—W �-55—m-9B-80�B8-8B-58—d-8�T p-80—M-9 88�p—EE-88—p i—W—BE—BB-9B � 0�—98-5—%—BB—S—�—d-68—Ba—$—d-68—Yid—BBB—S-8E-88—E \ _W—W —W/ W—W W—W / W—W—WSW—Wl�—W—W —W—W —W fW—W—W—W—W JW—W—W —W W—W—W—W—W—W—W—W—W—WAY/—W—W—W—W—W—W� W—W—W—W—W—W—B LEGEND PROPERTY UNE — — EMSDNG EASEMENT UNE EMSDNG MAJOR CONTOUR EMSTING MINOR CONTOUR PROPOSED MAJOR CONTOUR pgTo PROPOSED MINOR COUTOUR 4967— EMSTNG EIECTHIC UNE E — E FASTING GAS UNE GAS— GAS— EMSTNG TELEPHONE UNE T — T EAWNG SANITARY SEWER SS— SS EMSTNG WATER UNE W — W PROPOSED WATER UNE FENMIJ K E%ISTNG WATER METER EDwM PROPOSED WATER METER W EMSTNG nRE HYDRANT kJ EMSTMGWATER VALVE EMSTMG11POWER POE EMSTNC SANITARY SEWER MANHOLE 0 PROPOSES SANITARY SEWER MANHOLE • EMSTNO ELECTRIC PEDESTAL u EMSTNG TRIMS FLOW ARROW EMSTING,UMT POST PROPOSED INFLOW OR OUTFLOW C" PROPOSED FLAT CURB @ OUTTEIR PROPOSED SUB-BASN BOUNDARY BA4N AREA MPERNOUS (f0 { is PICPOSED LCNLREIE PRaPosm AmN,u.r HYDROLOGICAL FLOWS CITY OF FORT COLLINS, COLORADO DEVELOPED DEVELOPED UTILITY PLAN APPROVAL SUB -BASIN AREA (aa) 0. (cfs) 0 efW S1 0.34 0.40 1.70 S2 0.83 1.10 5.30 GRAPHIC SCALE 1E �ENGMR DAM au:aWDBY: _ WATNR 6 WASTEWATER URITY DATE (mod rvr I i CONTRIBUTING REQUIRED AVAILABLE RELEASE 100-YEAR HIGH W' CBEUhTBY: POND BASINS VOLUME (CF) VOLUME (CF) RATE (cfs) WATER ELEVATION STDRMwATERImIn DATE PICP SUB -BASE I S1 1883 2707 0.20 50354] LIIECPFD BY: PN &RECRFATMN DATE Know wears below. C211 before you dig De ,RAERLENGIIEER BATE } i CH Der: ENJIRCNMEMAL% WER DATE 3 o� JC� z1 a h V Q 4a � Z H- LL a Wg K x K � �$ z xSCD a m z Z 9 1'=20' OF 10 — — — �m�— LtlAFAEI£CIRICSEF R EngIXN'\ AND I I EImR MMMW + K aAW7M FNPIH — siAsglID ��M —fM �Y9 FJ-TV �Y �YJ� BOO— �•9 �N �6MJ tiY0 BIRCH STREET —W—N—W—M9 M—M—a a—s �W a-99—W—N�88-5E—p— LAC A , / aN� n\J 1 41Ab51811 + a _ � _.•,�.... \ ALE_ - _ \ � BYSANMRYWAFXf —b—BB-88-88�.p Y—94—®-98 i CITY OF FORT COLLINS, COLORADO UTILITY PLAN APPROVAL MiE CLIYEpiMFfli LHECNFDBY' WAlEA6 WA5iEWR1ERMLnY DAM CN EDBY: SIpiMYAIEAURLIY MA CHECNEDBY: PMHSAPECRFAMNI DAM cffi R BY: nUIFlCBIAMEER mm CNEC By ENVIROWEMKRANEA MR ®9 N�YD tip-�SYD�— = Y= �YJ yq�N �MJ �YB �Y9 �YJ �6m1 — BiApO r —0-86-6—n-98—S-6—p—N %—m—m— R a G�5 S mrh 0 �€ 8t�1 RgRo 11,12 RsR s ;a a�, ESa g� H Sq%1 � €€3 t' 7 S`Gn Irk WI Goo .5035.0 Mau. MMLF. W]blF. BDM B'0PF%CNA1F➢PN BW% Opll{ 1N.W LF. 040% 6'CWC Btl F9dQWEBPrC 6'6 ffliaNIFB WC HALF. Iosl F. aNsx aesaoPac 1 5030.0 5 PRa'OSFD NOTES: 1. ANCHOR ALL SOLID PVC PIPE PIPE THAT LIES OUTSIDE OF PICP AREA PER PIPE MANUFACTURERS RECOMMENDATIONS. 2. MAINTAIN MINIMUM ONE -FOOT COVER OVER SOLID PIPE. Know whaPs WOW. Callbeforeyoudig UVOO Q�LI—LJ GRAPHIC SCALE (pRP) I W� B B M1 oas i g O C 5045.0 000 8 wU SS 3� �5 R 5040 0 00 Z i w F 0 K F o a z Z �$ 5 0 h g z x i0 w N z V sls JFB xwEaeEnn,ans SGLE NTRgRAL I'1J VEHIIGL: I'4 Pp[CI W. RAYYIIY %SpIS