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Home My WebLink AboutDrainage Reports - 02/11/2019City iF Approve Plans Appro Date: FINAL DRAINAGE AND EROSION CONTROL REPORT Streets Park Tract A, East Vine Streets Facility P.U.D., Lots lA & 2A, a replat of a portion of Lots 1 and 2, East Vine Streets Facility RUM, Major Amended Final, Phase Two Final located in the northeast quarter of Section 12, T-7-N, R-69-W of the Sixth Principal Meridian City of Fort Collins, Larimer County, Colorado Prepared for: City of Fort Collins Park Planning and Development 215 North Mason Fort Collins, CO 80524 Prepared by: Interwest Consulting Group 1218 West Ash, Suite A Windsor, Colorado 8050 (970)674-3300 November 28, 2018 Job Number1165-012-92 November 28, 2018 Mr. Dan Mogen City of Fort Collins Stormwater 700 Wood Street Fort Collins, Colorado 80522-0580 RE: Final Drainage Report for Streets Park Dear Dan, I am pleased to submit for your review and approval, this Final Drainage Report for the Streets Park development. I certify that this report for the drainage design was prepared in accordance with the criteria in the City of Fort Collins Storm Drainage Manual and previous reports for this site. I appreciate your time and consideration in reviewing this submittal. Please call if you have any questions. Sincerely; A4Z��. 1/0 ,� iil�s Michael Oberlander, P.E., LE ED AP ' 'A '• Colorado Professional �`rs/ONAL Engineer No. 34288 ii TABLE OF CONTENTS ............................................................................................................ iii 1. GENERAL LOCATION AND DESCRIPTION ................................................................ I 1.1 Location ......................................................... ....................... 1 1.2 Description of ......................... I 1.3 Floodplain Submittal Requirements ............................................................................. 2 2. DRAINAGE BASINS AND SUB -BASINS .......................................................................... 2 21 Major Basin Description ... .. ............................................................................................ 2 p . ................................................ .......................... . 2.2 Sub -basin Description ............................................................................................................. 3 3. DRAINAGE DESIGN CRITERIA ...................................................................................... 3 33 Regulations...' ........................ , .. . ................ . . ............................ . ...................................... 3 3.2 Directly Connected ImperviousArea (DCIA) Discussion.....,-,,., ................................. 4 3.3 Development Criteria Reference and Constraints ...................................................... 5 3AHydrological Criteria ..................................................................................................... 6 3.5 Hydraulic Criteria....... ................................................................................................... 7 3.6 Floodplain Regulations Compliance ............................................................................. 7 3.7 Modifications.of Criteria_....................................................................................:::....... 7 4. DRAINAGE FACILITY DESIGN 4.1 General Concept ...................... 41 Specific Details ......................... 5. CONCLUSIONS .............................. 5.1 Compliance With Standards .... 51 Drainage Concept ..................... 6. APPENDIX ...................................................... 7 ...................................................... 7 ...................................................... 9 — . ............. ............................................................... 12 ............................................................... 12 ............................................................... 12 ......................................................................... ..... 13 VICINITY MAP AND DRAINAGE PLAN .............................................................................. A EXISTING DRAINAGE REPORT SUPPORT MATERIAL .................................................. B DRAINAGE INFORMATION .................................................................................................... C ------------ POND..... ..................... .......... D LID INFORMATION ............................ ...... ................... * ............. ****E STANDARD OPERATING PROCEDURE ............................................................................... F STORMWATER ALTERNATIVE COMPLIANCEIVARIANCE., .................................... G iii GENERAL LOCATION AND DESCRIPTION 1.1 Location The Streets Park project is located in the Northeast Quarter of Section 12, Township 7 North, Range 69 West of the Sixth Principal Meridian, in the City of Fort Collins, Larimer County, Colorado. Please refer to the vicinity map in Appendix A. Vine Drive and the BNSF Railroad Right of Way bound the site on the north; 9'° Street ' (Lemay Avenue) bounds the site on the east, the New Belgium Brewery is located on the south, and the existing City Streets and Traffic facility is directly to the west. The site ' was platted with the overall Streets Facility as Tract A of the East Vine Streets Facility P.U.D. in 1993. Tract A was platted as a blanket Drainage and Access Easement and provides water quality and detention for the East Vine Streets Facility P.U.D. (all of the City land from 9th Street to Linden). 1 1.2 Description of Property ' Tract A consists of 8.5 acres of land and was always planned to be a stormwater and recreation facility. Today the existing driveway from 9'h Street into the Streets facility exists on the south side of the site.. A railroad spur is located on the north portion of the ' Tract. Water Quality Pond A is located on the west side of the site (south of the spur), and Water Quality Pond B is located north of the spur. A basketball. court, picnic shelter and small parking area have been developed on the west side of the Tract adjacent to the driveway. The remainder of the Tract is the detention pond for the Streets Facility. It accepts discharges from both water quality ponds. The pond drains east to an existing 18" pipe and into the storm sewer system in 9' Street. There was an asphalt sidewalk on 9'h Street that acted as the initial spillway for the pond. This walk and spillway was ' recently rebuilt by the city in concrete. ' Tract A generally slopes east at approximately 0.5% to 2%. The land is currently vacant except for the facilities described above. Based on previous reports, the only flow contributing to the site is the City Street Facilities to the west: According to FEMA Panel 08069CO981G (6/17/2008), the site is in Zone X - Protected by Levee. IThe site has been studied numerous times in the past. Pertinent portions of these studies will be discussed in this report regarding C Values, release rates, and pond volumes. 1.3 Floodplain Submittal Requirements The site is in Zone X, and because of this a Floodplain Submittal is not required and a "City of Fort Collins Floodplain Review Checklist for 100% Submittals" has not been included with this report.. 2. DRAINAGE BASINS AND SUB -BASINS 2.1 Major Basin Description The proposed development ties within the Dry Creek Master Drainage Plan. Outfall for this site is the storm sewer system in 9`s Street and then Dry Creek. The previously approved release rate for the existing site pond is 10.5 CFS (more than the Master Plan requirement of 0.2 CFS per acre). The site was previously studied with the following reports. • "Final Drainage, Erosion and Storm Water Quality Study, East. Vine Streets Facility P.U.D., Phase One Final", by RBD, June 28, 1993. (The 1993 Report) • "Final Drainage and Erosion Control Study, East Vine Streets Facility P.U.D., Major Amendment Final, Phase Two Final", by The Sear Brown Group, August 3, 1999. (The 1999 Report) • "Final Drainage and Erosion Control Report, East Vine Streets -Lot 5A City of Fort Collins Traffic Operations Facility", by The Sear Brown Group, March 25, 2002. (The 200.2 Report) The 1993 Report sized the two water quality ponds with the FAA/Rational Detention Method (prior to UDFCD guidance) as well as the detention pond with the FAA Method. The "C" Value used for the sizing was 0.56 and the "old" City of Fort Collins Rainfall Was utilized with a contributing area of 29.8 acres and a release rate of 10.5 CFS. The detention volume required was determined to be 2.77 acre-feet and the detention volume provided was 1.33 acre-feet. The designer added the 1.5 acre-feet of water quality volume to the provided detention volume to conclude that the required volume was achieved. K 1 The 1999 Report re -sized the facilities again with the FAA Method for all three ponds. The "C" Value used for the sizing was raised to 0.77 and the `old" City of Fort Collins Rainfall was again utilized with a contributing area of 29.41 acres and a release rate of 10.5 CFS. The detention volume required was determined to be 4.17 acre-feet and the detention volume provided was 2.61 acre-feet. The designer added the 1.6 acre-feet of water quality volume to the provided detention volume to conclude that the required volume was achieved. The 2002 Report did not analyze the detention pond and will not be discussed further. Please refer to Appendix B - Existing Drainage Report Support Material for reference. 2.2 Sub -basin Description Tract A mostly contains existing water quality and detention facilities. There are several parking spaces, a picnic shelter, basketball court and the main access drive from 9`s Street on the site — all of these facilities were shown on the original construction plans for the site and presumably were included in the drainage calculations. On Tract A, the existing driveway sheet flows to the south and never drained to the detention facility. This configuration will not be changed with the development of the park. The proposed project will regrade the detention pond so that it will function adequately as a recreation field with 1% minimum slope, install a restroom facility, larger picnic shelter, and playground with safety surface. Additional parking is proposed along the existing drive and LID treatment of this new impervious area is proposed. The core of the new park (new structures and playground) will be elevated and will fill within some of the existing detention pond volume. The project will regrade the pond so that the detention storage in the pond in conjunction with available storage volume in Water Quality Pond A will be; achieved with the "new" 1997 City of Fort Collins rainfall. DRAINAGE DESIGN CRITERIA 3.1 Regulations This report was prepared to nieet or exceed the "City of Fort Collins Storm Drainage Design Criteria Manual' specifications. Where applicable, the criteria established in the 3 "Urban Storm Drainage Criteria Manual" (UDFCD), developed by the Denver Regional ' Council of Governments, has been used. The release rate approved in 1993 and 1999 was used for a release rate from the site and for recalculation of the required detention ■ volume. 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. The park development will add very little impervious area, with respect to the overall site.. Many of these criteria are not applicable to a project with such a minor drainage impact. Step I; 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 Impervious Areas (MDCIA). The core area of the park will be within an existing detention facility.The west portion of the core area will sheet flow into Water Quality Pond.A and the east portion of the core area will flow into the playground safety surface and underdrain (which is effectively like a rain garden). The new parking proposed along the driveway will drain east and through a new rain garden to meet LID requirements. Step 2: Implement BMPs that Provide a Water Quality Capture Volume with Slow Release A rain garden is proposed for the new parking along the driveway. This will result in a slower release than if it simply sheet flowed south across the driveway. 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 detention pond, bank stabilization is unnecessary with this 4 project. Step 4. Implement Site Specific and Other Source Control BMPs As a park, the proposed development will not increase pollutants that require treatment. The panting spaces (which could have sands, salts, and leaking fluids from cars) will drain to a rain garden. 3.3 Development Criteria Reference and Constraints The runoff from this site has been routed to conform to the requirements of the City Stormwater Department and previously approved reports for the overall site. The detention calculations were approved in 1999 with the `old" City rainfall (apparently the site submitted for review prior to the rainfall change in early 1999 and was vested). The existing water quality facilities on the west side of the site are upstream of the project ' and intended to treat the Streets Shops and Facilities. These ponds will riot be upgraded or changed with this project. LID techniques are required — pavers are not proposed, so no less than seventy-five percent of any newly added impervious area must be treated using one ora combination of LID techniques. New impervious area in the park including the new parking spaces was determined to be approximately 16,854 sf, by calculating the difference of impervious, areas between the proposed conditions to pre -project conditions. The restroom and walks on the west side of the core area (approximately 3,713 sf impervious) will drain west and into Water Quality Pond A. It is our understanding that the City would like to upgrade this water quality pond to a rain garden in the future, but at this time, this impervious area is not considered. treated by LID. The east portion of the core area (shelter and playground — approximately 2,049 sf impervious) will be treated within the subsurface of the playground. Inside the perimeter of the playground will be a wood fiber media that will allow infiltration to a 3" layer of drainage gravel below the wood fiber media and surrounding a perforated sub -drain (very similar to a rain garden). The new impervious surfaces in this area were calculated to require 81 cf of WQ storage with the rain garden calculator. Approximately 175 cf of storage is available on the wood fiber media which will be bounded by a perimeter 5 curb/barrier. This area is considered to be 100% treated by LID. The remaining portions of the interior walks drain to the detention pond (approximately 10,445 sf), where the majority of walks sheet flow across an extensive amount of grass at shallow grades.. There is no reasonable expectation that these concrete walks need additional water quality provisions, however 7,766 sf of these walks are being considered as treated. This is due to this portion of 8' wide walks draining across an average of 300' or more of grass before exiting the detention pond, which would be over a 30:1 ratio of impervious to pervious material. The 7,766 sf of walk treated by the grass buffer are considered to be 100% treated by LID. The new parking .spaces and adjacent sidewalk will add 3,815 sf of impervious area. These parking spaces need to drain to the south, as they are lower than the top of the detention pond berm. The design will capture the minor storm in a new 4' trickle pan on the south side of the new parking spaces and take that niinor flow east and to a new rain garden. Any flows that overwhelm the pan or the rain garden will sheet flow to the south over the existing driveway and then east to 9`s Street in a swale on the south side of the driveway. The parking spaces are considered to be 100% treated by LID. The new impervious area created by the project that is treated by LID is 81%. There is a small portion of sidewalk that cannot be treated for water quality (2565 sf). A variance is included for this area. Please refer to Appendix E — LID Information for additional information. 3.4 Hydrologic Criteria Runoff computations have been prepared for the new park to demonstrate that there is no appreciable change in the imperviousness of the overall site when the existing Streets Facility is included:. The 1999 Report determined the composite C Value for the overall basin to be 0.62, which yields an impervious value of 53% or 15.59 acres of hardscape on the 29.47 acre site. Whereas the proposed conditions for Basin A (draining to the detention pond) will add 0.24 acres of hardscape. In effect, this is a 1% increase in imperviousness for the overall 29.47 acre site and it changes the C Value to 0.63. 6 Basin B (draining offsite) today releases a Q1Q0 of 5.9 cfs and with the parking and walks added that cannot drain to the detention pond will produce 7.1 cfs in a 100 yr event, which is 1.2 cfs more than what was calculated for the historic (existing) condition of the site,. To account for the 1.2 cfs increase in runoff from Basin B, the detention pond release rate is being reduced to 93 cfs. Please refer to Appendix C — Drainage Information for additional information. 3.5 Hydraulic Criteria No hydraulic calculations have been prepared. Two existing storm pipes will be extended with the project — these new pipes have been sized larger than the existing pipes. 3.6 Floodplain Regulations Compliance The project is located within a shaded FEMA Zone X, according to map number 08069C0981G. This Zone is for areas of 0.2% annual chance flood; areas of 1% chance flood with average depths of less than I foot or within drainage areas less than 1 square mile; and areas protected by levees from 1% annual chance flood. Based on the FEMA Flood Map Service Center, the site is within an area with reduced flood risk due to levee. 3.7 Modifications of Criteria The drainage design has been prepared assuming that the project's release rate can remain at the previously approved rate of 10.5 cfs. DRAINAGE FACILITY DESIGN 4.1 General Concept Existing drainage scheme: The latest pertinent design of the East Vine Streets Facility (the 1999 Report), routed the southwestern portion of the overall facility (14.85 acres) to Water Quality Pond A and the northwestern portion of the facility (7.52 acres) to Water Quality Pond B. The water quality ponds released individually into the detention pond. A concrete pan exists from 7 the outlet pipes to the 18" detention pond outlet pipe at 9"' Street. The detention was ' undersized because the City's old rainfall criterion was used. The 1999 Report design showed the invert of the pond at elevation 46.2 and the spillway to 9' Street at 4949.2 ' with a design volume of 2.61 acre-feet. At some point after the construction of the ponds, curb and gutter was added to 9" Street as well as an asphalt sidewalk between 9'" Street and the pond. The old asphalt sidewalk appears to have significantly raised the spillway elevation of the detention pond with the lowest point of the walk being at elevation 4950.J, The survey for this project indicates that the pond (with the additional 0.9' of depth) exceeds the 1999 design volume with a detention volume of 4.97 acre-feet. The pond is deficient in that there is a low point in the driveway at elevation 4950:3, so if the pond ever were to spill, it would spill both east to 9`" Street and to the south towards New Belgium Brewing once a water surface elevation of 4950:3 was exceeded. Since the survey for this project was performed, the asphalt sidewalk between 9`s Street and the pond has recently been reconstructed in concrete, with the previously submitted proposed grading plan used as a guide for construction of a higher spillway elevation. Proposed drainage scheme The existing pan from the two water quality ponds runs through the center of the proposed core of the park. Several options to reroute this pan were investigated, but in each case, the reroute would take the pan between the playground/shelter and the turf field, which will be a high traffic area. The goal of the project was to avoid any park users from having to cross this trickle. The current design solution will reroute the pipe from Water Quality Pond B into Water Quality Pond A and then route the outlet pipe from Water Quality Pond A through the playground and to the south side of the site. A swale will be built at the toe of the south embankment at 0.5% to the detention pond outlet pipe. This swale area will be planted in a way that discourages pedestrians from crossing it. The detention pond volume has been recalculated with the 1999 Report acreage, the new proposed C Value (0.79) and new release rate (9.3 cfs), and with the current City of Fort 8 1 I Collins rainfall data. The core area of the park is encroaching into the existing pond ' volume and the regrading of the bottom of the pond (to get a standard l% slope) will also take some of the existing volume. To counteract this, the spillway will be lengthened and 'raised slightly, and the south berm of the pond will also be raised to an elevation 12" _ above the spillway (to remove chances of spilling over the drive). A headwall and orifice plate will be added to the pond outlet structure to reduce the flow to the 9.3 cis release ' rate. ' Parking will be added to the drive, but it will be treated in a rain garden prior to the underdrain releasing to the 0.5% swale within the detention pond. 4.2 Specific Details A summary of the drainage patterns within specific areas of the project is provided in the following paragraphs. Hydrology of the basins west of the project were not analyzed, as the previous reports were used for overall C Values and no new conveyance pipes are proposed. Please refer to Appendix A for the Drainage Plan. tWater Quality Pond B is north of the railroad spur and currently has 0.56 acre-feet of volume prior to water spilling over the railroad tracks into Water Quality Pond A. . Presently, the pond drains through a 12"x18" HERCP pipe (15" equivalent) to the trickle pan in the detention pond. The proposed design will add a manhole on this pipe on the south side of the railroad spur and extend an 18" pipe to Water Quality Pond A. Water Quality Pond A is south of the railroad spur and west of the proposed park core area and the detention pond. It accepts runoff from the existing streets facility both overland through a curb cut and from an existing 30" pipe. The pond has an existing volume of 1.59 acre feet prior to spilling east into the detention pond. The pond outlet is an 8" steel pipe which currently drains to the existing trickle pan in the detention pond. The proposed design will add a_ junction box (area inlet) on the downstream. side of this 8" pipe. A new, solid 12" PVC pipe will be run through the proposed playground and will discharge into the detention pond on the south side of the core area. This IT' pipe will be placed on the subgrade of the playground with drainage gravel around it and engineered wood fiber safety surface above it. The pipe will be readily accessible if any maintenance is required. i ' Additionally, the grading of the east side of Water Quality Pond A will be changed. Today the spill elevation of the pond is 4950.7. This spill location is directly adjacent to the proposed restroorn and core area. With the new grading design of the detention pond, Water Quality Pond A will spill northeast at an elevation of 4951.0. The bottom of the detention pond will sheet flow at 1% to the southeast and be the new spillway for the Water Quality Pond. No erosion protection will be necessary as it will basically just spill into a flat field. With the increase in the spill elevation, the new volume associated with Water Quality Pond A will be 1.99 acre-feet. It is assumed that in the future the streets department will reconfigure this pond into a rain garden or some LID treatment basin. Extended Detention Basin calculations were performed on all areas draining to the water quality ponds. These calculations show a total required Water Quality Capture Volume of 0.65 acre-ft, so 1.34 acre-ft of excess storage is available. The Core Area is located north of the existing drive and new parking, and between Water Quality Pond A and the Detention Pond. It will contain a new restroom (set 12" higher than the top of the detention pond berm), planting beds, walkways, an open air picnic shelter and the playground for the park. The core area is elevated above existing grade and will drain west and east. The west portion of the site will drain overland into Water Quality Pond A, the east portion of the site will drain into the playground safety surface. The safety surface is an engineered wood fiber that will be least IF deep with a layer of drainage gravel below that will surround a 6" perforated pipe in the bottom to drain runoff to the detention pond. The Detention Pond was designed in 1993 with the first construction phase of the East Vine Streets Facility P.U.D. 'Today the detention pond outlets.to an uncontrolled 18" pipe in the southeast comer of the pond and into the storm sewer system in 91 Street. The existing volume of the pond is more than was designed, but the spill elevation was artificially raised with the construction of the asphalt sidewalk on 9`^ Street, and the pond bottom is much flatter than was designed with slopes as flat as 0.40%. The construction of the park core area will fill within the existing detention volume as will steepening the bottom of the pond to 1% minimum (required for usable turf fields). The goal of the project was to calculate the required pond volume with the current City of Fort Collins rainfall and control the release of the pond with a new orifice plate on the 10 18" outlet pipe. Using the acreage from the 1999 Report, along with the new C Value, release rate, and rainfall data, the required detention pond volume is 5.20 acre-feet. As mentioned previously, the asphalt sidewalk along the east rim of the detention pond was recently reconstructed in concrete. The walk was rebuilt with an approximately 100' long spill elevation of 4950.2 (design elevation of 4950.3). Calculations for the spillway sizing are provided in Appendix D. The south side of the pond will also be reconstructed to a minimum elevation of 4951.3 so that the secondary pond spillway is removed. The bottom of the pond has been designed with a 1% minimum slope in the open field areas, and a 0.5% grass channel on the south toe of the pond (which will receive flows from the core area and Water Quality Pond A). The detention pond volume achieved with these various grading modifications is 4.57 acre-feet, not including any detention within the water quality ponds. The additional required volume of 0.63 acre-ft to achieve the total volume of 5.2 acre-ft is available in the excess volume of 1.34 acre-ft within Water Quality Pond A. The proposed spillway for the detention spillway has been built approximately IM ft long. Using the FAA Detention spreadsheet and a time of concentration of 25 minutes (Rational Urbanized Check), the flow over the spillway is 118 cfs and will flow at a depth of 0.6 feet.. A variance for this flow depth has been included. The New Parking Spaces are located on the north side of the existing driveway. The driveway in this area is lower than the top of the detention pond, so it is not possible to sheet flow the parking spaces into the pond. In an effort to provide water quality for this new hard surface area, a 4' trickle pan will be run on the north edge of the driveway to accept the concrete parking spaces and the adjacent walk. This pan will be graded at 0.35% to the east and drain to a new, small rain garden. The sizing of the pan and rain garden follow: Total area of "New Parking Spaces" Basin = 5751 SF Area of Concrete Pavement = 3,815 SF Percent Impervious = 66 % C Value = 0.70 Q (2-year for pan) `= CiA= (0.70)*(2.85)*(575l/43,560) = 0.26 cfs Calculations for the rain garden are included in the appendices. It will have an 80 SF bottom at elevation 5049.5 and will pond 9" deep prior to overtopping the north edge of the driveway. e The EAsting South Driveway is south of the detention pond. The driveway is already lower than the existing pond spillway and it is impossible to drain the driveway to the pond. The original design of the Streets Facility showed this configuration. 1 5. CONCLUSIONS 5.1 Compliance with Standards All computations that have been completed within this report are in compliance with the City of Fort Collins Storm Drainage Design Criteria Manual and the previously approved reports for the site. 5.2 Drainage. Concept The proposed drainage concepts presented in this report and on the construction plans adequately provides for stormwater quantity and quality treatment of proposed 1 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. 12 6. REFERENCES I. City of Fort Collins, "Fort Collins Stormwater Criteria Manual Amendments to the Urban Drainage and Flood Control District Criteria Manual", adopted December 2011. 2. Urban Drainage and Flood Control District, "Urban Storm Drainage Criteria Manual", Volumes 1 and 2, dated June 2001, and Volume 3 dated November 2010. 3. "Final Drainage, Erosion and Storm Water Quality Study, East Vine Streets Facility P.U.D., Phase One Final", by RBD, June 28, 1993. 4. "Final Drainage and Erosion Control Study, East Vine Streets Facility P.U.D., Major Amendment Final, Phase Two Final", by The Sear Brown Group, August 3, 1999. 13 APPENDIX A VICINITY MAP AND DRAINAGE PLAN A VICINITY MAP SCALE: i " = 1000' 91Y R.Y.R'W 11EICS Sill — — MMf — _ FK.KUO 6V1I5/ PttC �- i i WATER QUALITY " ; le r` j III POND IAMT,SWMhVMN I I \\ •try`\ � I � p'i`,a crs �1 I�d� � wm.w.z /c LOT 2A. A REPLAT OF A PORTION OF 1-07111 AND 2, EAST VINE STREETS FAC ILITT P.U.D. I \\ \ �MOR AMENDED FINAL --� PHASE TWO FINAL AJ! j... Pool; i � —� �', \ / L ,DETENTION POND I I ' IdMt IXI% ' \ A, / ." / A.EAiFYNFSIREEEH ACRIFT /v IkGE EASEMEM -- �i-- - _ I \ ` _ i- s v. WATER QUALITY AN PONDA / \ -Cii 1 all pESIpNATFD I pEF gjpO�ON FFs10 CORE AREA ^ i ( I T ,✓ / / ° \Y'� ��` r I I �., - I � ,�. • it I Ir we - \EAMT A Ixal ` LOT IA. A REPLAT OF A 11_q�{�y'\\\ 4r" �m L /V I ee rFrcpR. YEAQ Aa1 / \ nre• / PoRTINE MAIOIE / E PLYINES RAM AMENDED Y •:J IILI L J P.0 O.. MAJOR AMENDED I' ! 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ALLSIORMWATERFACRFHIESW,LLBEPTVATELYWIWAINEOPIOTWJNTNN BYCm SfORLTNATERI LEGEND OfiAINAGE ROW APAOW _ _ DR+VNAG6fl45M BCWAARY E%MNDRLONtIXM �� pRLp05EDMAlpRCgiFOVR Sp% PROFV SEDNMDRCONTOIIR 40 20 O 40 so SCALL 1"=q0' '�- ADaAeveb'appm�pn, ' -- P&* PWvft d Dewbpllenl Ipy my)�. :,S NppEWV1 EYFR 149TOZZiANN)MR Sp5T1 AACI[OI � � yE BTp131B]ap r II PRELIMINARY II NOT FOR CONSTRUCTION i wow s'R¢T DTY OF FORT CaLL CCLORADO UTRITY PLAN APPROVAL APPNOWD: m10O@ brz CNE040 C FDUD BY: D OQD BY NMAs.ImrA,u w CREOOD OF: N; OE04D ST: OALL MITY MDTCICATION CDJIER OF OOLORADO 1-800-922-1987 a^ 534-6700 m " V1Ll EM1EE5 W VA 6PE YGl p4 4PA'IE tAM EY1.vI.i ibITE �Np OiLXES uwc O YW z� �W JO F O O LL w U �U Ha �U) OZ W> o LL L L J O O coV J U O PROJ.RO. 11S5-01 -92 DRAM IN CHECKED: MPO APPROVED'. LATE. OSQOW18 REVBENIS: STREETS PARK ISSUEDFOR: BASIC DEVELOPMENT REVIEW SHEET TIRE: DRAINAGE PLAN SCALE: I'=EO' SHEET NUMBER 8 APPENDIX B 1 EXISTING DRAINAGE REPORT SUPPORT MATERIAL 1993 Report Calculations 1999 Report Calculations m I copy was FINAL DRAINAGF, EROSION EAST VDM S1REEn FACULM P.Z7 D. MY OF FORT COMBS March 1, 1993 Revised April A 1993 Updated June 28, 1993 Prepared for. Client: Vaught Frye Architects, P.C. 1113 Stoney HM Drive Fort &llins, Colorado 80525 Owner: City of Fort Collins Streets Department 700 Wood Street Fort Collins, Colorado $0522 Prepared by RBI), Inc. Engineering Consultants 209 South Meldrum Street Fort Collins, Colorado 80521 (303) 482-5922 RBD Job No. 183-020 from the City of Fan Collms Public Records Webute: C No Text DETENTION POND SIZING BY FAA METHOD R@D/NC DEVELOPED BY TOB AAA 103-012 JAMES C.Y. GUO, PHD, P.E. BY KW G DEPARTMENT OF CIVIL ENGINEERING acu, evliWG?,pal f UNIVERSITY OF COLORADO AT DENVER EXECUTED ON 05=22-1991 AT TIME 12:46:06 PROJECT TITLE: CITY OF FORT COLLINS STREETS FACILITY MAJOR BASIN 1 i r *** DRAINAGE BASIN DESCRIPTION BASIN ID NUMBER 1.00 WIN_AREA (acre)= 2.9.80 RUNOFF. COEF = 0.56 (_DEU620PED COMC MDAI) ***** DESIGN RAINFALL STATISTICS DESIGN RETURN PERIOD (YEARS) = 100.00 f INTENSITY(IN/HR)-DQRATION(MIN) TABLE IS GIVEN DURATION 5 10 20 30 40 50 60 INTENSITY 9..0 7.3 5.2 4.2 3.5 3.0. 2.6 ***** POND OUTFLOW CAPACITY 80 100 126 150 180 2.1 1.7 1.5 1.1 1.0 MAXtMwh A64- RELEASE RATE = 10.5 CFS �BflS/N Et QZ hi157�lG� ***** COMPUTATION OF POND SIZE -------------------------------��__---------- RAINFALL RAINFALL INFLOW OUTFLOW REQUIRED _DURATION INTENSITY VOLUME VOLUME STORAGE MINUTE_yINCH/HR ACRE -FT ACRE -FT. ACRE -FT --- 0.00 0.00 0.00 oeoo 0.00 5.00 9.00 1.04 0.07 0.97 10.00 7:30 1:69 0.14 1,.55 15.00 6:25 2.17 0.22 1.96 20.00 5:20 2.41 Oe29 2:12 25.00 4:68 2:71 0.36 2.35 30.00 4.15 2.89 0.43 2.45 35.00 3.83 3.10 0.51 2.60 40.00 3.50 3.24 0.58 2.61 45.00 3.25 3.39 0.65 2.74 50.00 3.00 3.48 0.72 2.75 ■ 55.00 2.80 3.57 0.80 2.77. ®'t 60.00 2.66 3.62 0.87 2.75 65.00 2.40 3.62 0.94 2.68 70.00 75 00 2.20 2.00 3.57 3 48 1.01_ 1.08 2 56' 2 39 86.66 1:86 3.34 1.16 2 18 85.60 1666 3.15 1.23 1.92- 1 THE RAI- Ns unofficial copy was downloaded on May-10-2017 from the City of Fort Collins Public Records Website: http://citydo .fcgov wm or additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Savet Fon Collins, CO 80524 USA t/ (03 1 1 DETENTION POND SIZING BY FAA METHOD .DEVELOPED BY JAMS C.7. _GW, :PHR, P.E. DEPARTMENT OF CIVIL ENGINEERING UNIVERSITY OF COLORADO AT DENVER OM 11:2U4 PROJECT TITLE: CITY OF FORT ODlLIN4 STREETS FACILITY WATER WALITY POND A '•'• DRAINAGE BASIN DESCRIPTION RASIM ID NUMER • 0.00 RAIN AREA (acre)- 14.64 (BASI14S A -(r) ROAOFF COEF • 0.82 (OEV. COMPOSITE: -C- AT DE51(AW PT. GI) DESIGN RAINFALLSTATISTICS DESIGN RETURN PERIOD (YEARS) • 2.00 TMTHISITT(IFVRR)-DDRATTON(RIN) TABLE IS GIVEN O1IRATION 5 10 20 30 40 50 60 EO 100 120 ISO ISO INTENSITY 3.2 2.5 1.8 LS 1.2 1.0 0.9 0.8 0.6 0.5 0.4 0.4 POND MmW CBARACTERITTIM M4XIMI1I ALLCNARLIE RELEASE RATE a -1 CIS r-0461DE"b SMALL ENeLend T?) OUTFLOW ADJLSTMERi FACTOR a 1 ?ZCVIDE FOP - TIME .4 FOV 16 E 4L AVERAGE RELEASE RATE a .1 CFS (01FWAT)V E }j'j►.I� SIDE AVERAGE RELEASE RATE • MAXIMM RELEASE RATE • ADJUSTMENT FACTCR. '•"• COMPUTATI-09 OF- POW SIZE ..................................................... RAINFALL RAINFALL INFLOW CUTFLW REWIRED OURATIW INTENSITY VOLWIE VOLIRIE STORAGE MINUTE INCH/NR TORE -FT TORE -FT ACRE -FT -------------------------------------------------- 0.00 0.00 0-00 0.00 G.00 5.00 3.24 0.Z7 0.00 0.27 TO.00 2.52 0.42 0.00 O.<2 15.00 2.18 0.55 0.00 0.54 20.00 1.84 0.61 O. W 0 61 25.00 1.65- 0.69 6.60 0.& 30.00 1.47 0.74 0.00 0.73 35.W 134 0.78 0.00 0.78 40.00 1.21 0.81. 0.01 0.80 45.00 1.13 0.8C 0.01 0.B4 50.00 1.04 0.97 0.01 0.8E 55.00 0.98 0.89 0.01 6.89 60.00 0.91 6.91 0.01 0.90 65.00 0.87 '0.94 0.01 0.93 70.00 0.83 0.97 0.01 0.9E 75.W D.79 6.99 0.01 0.98 BO Do 0.75 1.00 0.01 0.99 S5:00 0.71 1.01 0.01 --L2L*- 90.00 0-67 LOt. 0.01 `0.99-" 95_00 0.63 1.00 0 D1 0.98 140.00 0.59 0.98 0.01 0.97 105.00 0.55 0.% 0.01 0.95 110.00 0.51 0.94 0.02 0.92 115.00 0.47 0." 0.02 0.89 This unofficial copy was downloaded on May-10-2017 from the City of Fort Collins Public Records Website:.http://citydms.fcgov.com For additional infonoation or an official copy, please contact City of Fort Collins Utilities 700 Wood Snreet Fort Collins, CO 80524 USA 6,3 THE REQUIRED POND_ SIZE a .99 &A ACRE -FT -dr,- THE RAINFALL MIRATION FOR THE ABOVE POND STORAGEn 95 MINUTES GEOMETRIES OF AN EQUIVALENT CIRCULAR FORD STAGE. CORTOUR CONT3IR FOND POND LDEPTN) DIAMETER .AREA SIDE SLP STORAGE .FEET FEET ACRE FT/FT ACRE -FT ----------------------------------------------------- 0.00 21.06 0.01 110r00 0.00 6.50 131._w 6.31 110.00 0.GB 1.00 241.06 145 110.00 0.42 1.50 351.06 2:22 110.00 1.24 2.00 "1.06 3.83 110.00 2.75 2.50 571,06 __w -S B .............................. 110.00 5,.18 11 1� it 1 11 II1 's unofficial copy was down loaded on May-10-2017 from the City of Fort Collins Public Records Website: M or additional information or an official coos. DlE contact City of Fort CoOms Utilities 70-0 Wood'Street Fort USA 0 DETENTION POND SIZING BT AA METHOD DEVELOPED BY JAMESC.Y. GOO, PXD, P.E. DEPARTMENT OF CIVIL ENGINEERING UNIVERSITY OF COLORADO AT DENVER EXECUTED ON 02-27-1993 AT TIME 09:23:16 PROJECT TITLE: CITY OF FORT COLLINS STREETS FACILITY WATER TRALITY POND B •a'• DRAINAGE BASIN DESCRIPTION -BASIN ID NUMBER • 0.00 BASIN AREi (acre)- 4.39 (BA61h1 H) RUNOFF COEF a 0.78 •'�•a' DESIGN RAINFALL STATISTICS DESIGN RETURN PERIOD CYEARS) • 2.00 INTENSITY(19/NR)eOURATIONC14IN) TABLE IS GIVEN DURATION 5 10 20 30 40 50 60 80 100 120 150 180 INTENSITY 3.2 2.5 1.8 1.5 1.2 1.0 0.9 0.8 0.6 0.5 0.4 0.4 a POND OUTFLOW CHARACTERISTICS - MAXIMUM ALLOWABLE RELEASE RATE • .1 CFS C09S1bMrD SMAW- FJ_-PWAN 727 OUTFLOW ADJUSTMENT FACTOR a I TROVIbE FOf- AFFRo}C- 40 HIZ• AVERAGE RELEASE RATE a .1 CFs D67>:JJ'�1C�.! TIME, �. PQaJIDE CvW5ERVAT I V E. P47kD S ICE. AVERAGE RELEASE RATE• MAXIMUM RELEASE RATE • ADJUSTMENT FACTOR. � COMPUTATION OF POW SIZE . _ ................................................. RAINFALL RAINFALL INFLOW OUTFLOW REQUIRED DURATION INTENSITY VOLUME- VOLUME STORAGE - MINUTE INCH/HR, ACRE -FT ACRE=FT ACRE -:FT 0.00 0.00 0.00 0.00 0. DO S.-w 3.24 0.08 0.00 0.08 1000 2.52 O:T2 0:OD 0.12. I5.Cb 2.18 O.T6 0.00 O:TS 20.00 1.84 9.18 0.00 0.17 25.00 1.65: 0.20 0.00 0.19 30.00 1.47 0.21 0.00 0.21 35.00 134 0.22 0.00 0.22 46.00 1.21 0.23 0.01 0.22 45.01D 1.13 0.24 0.01 0.23 5040 1.04 0.25 0.01 0.24 55AO 0.98 0.26 0.01 0.25 60AO '0.91 0.26 0.011 0.25 65.00 0.87 0.27 0.01 0.26 70.GO O-w 0.26 0.01. 0.27 75.00- M9 0.26 0.41 0.27 HAD 0.75 0.29 0.01 0..27 MAO 0.71 0.29 0.01 0.26 90.00 0.67 0i29 0.01 0 27 o.60 0.63 0.28 0.01 0'.27 iQ0-00 0.59 0.2 0.28 0.01 0.27 105-60 0.55 0.27 0.01 0.26 116.00 0.51 0.27 0.02 0.25 115.60 0.47 0.26 6.02 0.24 is unofficial copy was downloaded on May-10-2017 from the City of Fort Collins Public Records Website: http://citydms.fegm.com or additional Information man official copy: incase contact: City of Fort Collins Utilities 700 Wood Street Fort Collins. CO 80524 USA I .......... .:.:..... .:............ _. THE REQUIRED vW S ZE.* .2253065 ACRE -FT THE RAINFALL DURATION FOR THE ABOVE POND STDRAGE• 85 MINUTES fNN GEOMETRIES OF AN EQUIVALENT CIRCULAR POND STAGE CONTOUR CONTOUR POND POND (DEPTH). DIAMETER AREA SIDE SLP STORAGE ' FEET ---- FEET ACRE FT/FT ACRE -FT ................ - 0.00 .......................................... 2.36 0.00 87.00 0.00 0.50 1..00 69.36 176.36 0.14 0.56 87.00 87.00 0.04 0.21 ' 1 M 263..36 1.8 $7.00 0.67 2.w 350.36 2:21 87.00 1.53 2.50 437.36 3.45 87-M 2.9S 1 1 ' is unofficial copy was do"loaded on May-10-2017 from the City of Fort Collins Public Records Websim: http://citydms.fcgov com For additional' int'onnation oran official copy. please contact City of Fort Collins: Utilities 700 Wood Street Fort Collins. CO 90524 USA INC Engineering Consultants .I.T VAlil/HI F2)/P— ". Joexo./05-09.0 nnaecrrET/T� {yL11� '/_� r�� u�cuuTroiosson DE+ "f 70l I-1b�hl�/A! MWEBYyj+� DATE .pw .EG(ED BY_ DATE SWEET' I7 OP WR QUALi7y` ON IT. �� '� , ., • � , Ilfl 11 1 t 4 77 1 - 522`..0� i _ ,j _ 47 55950 fLi_GL'D • f j �oL d ff 275 <iC II 1' • 1 .,.J_' f.t..l A f I I. 4� 23 2z5. r> AyA 7 7 Armor t !^ Diarf • Dt-Ai>h E I 1 _ L Y tl t 1-�"- 1 I111, 1 Imo._--~• [.1 IT. 1- I 1��1 111,_ i 7.1 T 1 , /' 05Q� Prravr 7- - _•- I i- y rmEi 1 1 - wk fO ,4i7 �` ' --1 •_�L yj•�I-�/j-�((�,I 1 ///JJJ---I ' I I '�:*j.•_tT c/{y' I_ 1 , Io��-;�._I, ^i r, 77 T I - i- I , I I 1 I' 4SG 1 f �, 'G2 O ( �I 5� LI 5mo/ I tI I1, 1 /�/�//��//�� ✓_,} 1 J 1 if +1 1 _ �),/� �/ I/yL.j._ /,1 %Q JU unofficial copy was from the 01.10 W O FIrd Repot 0 Date, D O O �TY OF ` O O v `YbA9P�`g13%�.tlR 3Il ri>�f J— O O -- O o Final Drainage and O o O study East Vine Street !O0� n O `� O PoUeD., r �� Amended i M or Amen C � � O � base Two Final C - 21999 ion Control Facility Final, f1 O 5 O O G� -_ O 9 O O O O Fort Collins, Colorado O O O August 19 11 O o 11 .0 THE SEAR -BROWN GROUP Standards in Excellence s uaofEclal copy was downloaded on May-10-2017 from the City of Fort Collins Public Records Website http://citydocs.fcgov.com or additional iofonnanon or an official coy, please contact City of Fort Collins. Utilities 700 Wood Street Fort Collins, CO 80524 USA I 1 1 I 1 WATER QUALITY AND STORMWAT C] 1 1 1 1 I 1 Phis unofficial copy was downloaded on May-10-2017 from We Cityof Pon Collins Punk Records Wehsite: h¢p:1/ciryydocs.1cgov.com ZS 11 Fort Collins Streets Fadiity Composite Rational Method Runoff Coefficient for. Detention Pond Designer. SLG asm I AFea NO G Area o 'm 1993 Report C 227 0.95 2.16 ' D 123 6.95 1.17 E 2A9 0.95 2.37 - F 1AS 0.79 1.17 G 0.83 0.48 0.40 From Currant Report 0-2 021 0.25 0.06 03 0.54 0.25 0.14 '• 0-4 0.13 0.25 6.03 " 0-5 0.11 0.25 0.03 " 6-6 0.11 0.25 0.0.3 •' 4-1 1.85 0.90 7.67 Flom Wis ftlneering Report A-2 a79 0.45 0:35 ... From MuDerEngineering Report ... A-3 O: i3 0:35 k0 From MullerEiig rreenng Report; A-5 1.31 0.21) 0.26 From Mulle'Englnear}»g,l2eport 48-1 123 6.95 1.17 _ " 48-2 124 0.95 1.18 " 48-3 0.69 6.95 0.66 " H-1 0.93 0.41 0.38 " H-2 0.66 0.75 0.49 " H-3 0.48 0.95 0.46, H-4 027 0.54 0.14 '• H-5 1.87 0.95 1.78 Ponds 6.62 0.25 2.16 This indudes 0.18 ac from original 1993 H Basin L TotaL-_ 29A7 1827 Composite C for Basin: 0.62 Composite Cfor Basin 000-vr): 0-77 'Pram 7983 Pretlrtdnarr Drainage, Erosion. and Storm water Quality S%* for the East Vane Streets Facility P.UA Report "Basins A, B, 0.2. and H from the 1993 Preliminary Mainape. Eros on. and Stone Water Quality Study were divided funt erfor development design. 183-047 (Fort Collins) sis unofficial copy was downloaded on May-10-2017 from the City of Foil Collins Public Records Website: hug://citydocs.fcgov.wm n additional information or an official copy,. please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA I 2Cc, _______sass -ova - avvavema_-aaavvvaev_=mavvvvos QETENTION POND SIZING BY FM METHOD .. . _.-. Developed by Civit Eno. Dept., U. of Colorado Sported by Denver Metro Cities/Counties Pool Fund Study Denier Urban. Drainage and Flood Control District, Colorado USER�Cevin Gingery ........................................................... EXECUTED ON 06.28.1999 AT TIME 13•51-09 PROJECT TITLE: Fort Collins Streets facility - Overall.Site Detention Pond DRAINAGE BASIN DESCRIPTION BASIN 1D NUMBER a 1.00 BASIN AREA (sere)- 29.47 - Comprised of the following contributing.basins (exhibit on page 41: Basins from 2993 Report: C. 0. E. F, G Basins fran Current Report: 0-2. 0-3. 0-4. 0-5. 0-6. A-1. A-2. A-3. A-5. 48-1. 48-2. 4B-3, H-1. 8-2. H-3. H-4. H-5. Ponds RUNOFF COEF v 0.77 - From previous page DESIGN RAINFALL STATISTICS DESIGN RETURNPERIOD(TEARS) - 100.00 INTENSITY(IN/HR)-DURATION(MIN) TABLE IS GIVEN . DURATION 5 10 20 30 40 50 60 80 100 120 150 lab INTENSITY 9.0 7.3 5.2 4.2 3.5 3.0 2.6 2.1 1.7 1.5 1.2 1.0 •""' POND OUTFLOW CHARACTERISTICS: - MAXIMIM ALLOWBLE RELEASE RATE a 10.5 CFS - HIStoriC 02 for Basin El (See page 3 for exhibit and OUTFLOW. ADJUSTMENT FACTOR a 1 page 27 for calculation. AVERAGE RELEASE RATE - 10.5 CFS AVERAGE RELEASE RATE = MAXIMUM RELEASE RATE - ADJUSTMENT FACTOR. COMPUTATION OF FORD SIZE RAINFALL. RAINFALL INFLOW OUTFLOW REQUIRED DURATION INTENSITY VOLUME VOLUME STORAGE MINUTE INCN/NR ACRE -.FT ACRE -FT ACRE -.FT .::.:.:.-------------- . 0.00 0.00 .......... 0.00 ......_L_........ 000 0.00 - . 5.00 9.00 7.42: 007 7:35 10.00 730 2.30 0.14 2.f6 15.00 20.00 6.25 5.20 2.95 '3.26 0.22 0.29 2.74 2.49 25_OD 4.71) 3.70. 6.36 3.34 30.00 4.20 3.97 0.43 3.54 35.00 3.85 4.25 0.51 3.74 40.Do 3.50 4.41 0.58 3.83 ' 45.00 3.25 4.61 6.65. 3-96 50.00 3.00 4.73 0.72 4.60 S5.00 2.80 4.85 0.80 4.06 60.00 2.60; 4.92 D.87 4.05 65.00 2.47 5.07 0.94 4.13 70.00 2.35 5.18 1.01 4.17 75.00 242. 5.26 1.0s 4:17 8000 2.10 549 1.16 4.14 95.00 2.00 5-36 1.23 4.13 ' 90.00 1.90- 5.39 1.30 4.09 95.00 1.80 5.39 1.37 4.02 100.60 1.70 S.36 1.45 3.01 105.00 1_65 5.46 1.52 3.94 THE REWIRED POND SIZE.- 4.17,461 ACRE -FT THE RAINFALL OURATION FOR THE ABOVE POND STORAGE- 75 MINUTES is unofficial copy was downloaded on May-10-2017 from the City of Fort Coffins Public Records Website: hi r additional information or an official coov. please contact Citv of Fort Collins Utilities 700 Wood Street Fort -rr0 I I I I I I I I I we Engineering Consultants cusmT V"Wr E&� C Mma. I93-610 PAWECT -shesis Sk"; �-' — CALCULATIONSFOR #;n"r MADEBY XWe- DATE A -I" CHECKED By —DATE -. ----SMW 3—OF Y. — - ----------- C") D 74 4.66. ov4ki eAsiAgot) cGoiralejA015.) cis 0.9x 7c 7Z z' 77, 71�- am 'r- - O-zo -A —T _77 �1 � F I I 1 Fort Collins Streets Facility Cornoosite Rational Method Runoff Coefficient for Water Quality Pond A Designer. SLG Basin ac a es Firm 1993 Report C 227 0.95 2.16 ' D 123 0.95 1.17 ' E 2.49 0.95 2.37 ` F 1.48 vii 1.17 ' G 0.83 0.48 0.40 ' Hain Cunent ReporF +1 1.85 . 0.90 1.67 From WeirQ gir{ ift Report A2 0.79 d 45 . 0 36 FYorrt.Mul/ec Ehginee►ing Repo>7 A-5 1.31 0.20 0 26 Fmm MuW Engineering Report. 48-2 1.81 0.95 17J7 48-3 0.79 0.95 0.75 " TotaL 14.85 12.01 Coeiposite C for Bashi: 0B7 'From 19M Prelbntrtaiy Dialnedo. Erosion. and Sham Water Ouallty ..Study for the East Vine Streets Facility P.U.O. Report 'Basins A S. 0.2. and t1 from pre 1993 Preliminary Drainage. Erosion. and Storm Water Quality Study were dividW tarsier for developmem design. 183-047 (Fort Collins) was downloaded on May10.2017 from the by of Port Collies Public Retards Website: http://otydws.fcgov.wm I ' --=-=---------aaIIZIING BY FpCea-vvaeac-caave-=_a DETENTION POMD Si21N0 BT FAA METHOD . .. .. Developed by ' Civil Eng. Dept_„ U. of Colorado Supported by Denver Metro Cities/Counties Pool Fund Study Denver Urban Drainage. and Flood Control District, Colorado ee--ei - ------ - t USER -Kevin Gingery ........................................................... EXECUTED ON 06.28.1999 AT TIME 13:54:07 PROJECT TITLE: Fort Collins Streets facility - Hater Quality Pond A DRAINAGE BASIN DESCRIPTION BASIN ID NUMBER 1.0D BASIN AREA Caere)- 14.85 - Changed from 1993 report due to new delineation of sub -basin RUNOFF COEF 0.81 drainage in Basins A and B. Runoff coefficient calculation On previous page. DESIGN RAINFALL STATISTICS DESIGN RETURN PERIOD (YEARS) • 2.00 INTENSFTY(IN/HR)-DURATION(MIN) TABLE IS GIVEN DURATION 5 10 20 30 40 50 60 80 100 120 10 TBD INTENSITY 3.2 2.5 1.8 1.5 1.2 1.0 0.9 0.8 0.6 0.5 0.4 0.4 "••• POND OUTFLOW CHARACTERISTICS: ' MAXIMUM ALLOWABLERELEASE RITE n .1 CFS - Considered small enough to provide for approximately OUTFLOW ADJUSTMENT FACTOR = 1 40-hour detention time and conservative pond size. AVERAGE RELEASE RATE a .1 CFS AVERAGE RELEASE RATE • MAIIINUM RELEASE RATE • ADJUSTMENT FACTOR. "•�:' COMPUTATION OF POW SIZE 1 II 1 ................................................ RAINFALL RAINFALL iNFU.OI OUTFLOW REQUIRED DURATION INTENSITY VOLUME VOLUME STORAGE MINUTE INWHR ACRE -FT ACRE -FT ACRE -FT ------- ------------------------------------------ 0.00 0.0.0 0.00 DAD _--- 0.DO 5.00 3.2D 0.27 0.00 O.b 10.00 2.50 0.42 0.00 0.42 15.00 2.15 0.54 0.00 0.54 20.00 1.80 0.60 0.00 0.60 5.00 1.65 0.69 0.00 0.69 30.00 1.50 0.75 0.00 0.75 35.00 1.35 0.79 0.00 0.78 40.00 1.20 0.80 0.01 0.80 45.60 1 10 0.83 O.OT 0.82 50.00 1.00 _ 0:84 _. 0.01; .. 0:83 55.00 0.95' 0:87 6.01 O.B7 60.00 0.90 0.90 0.07. 0.89 65.00 0.88 0.95 OAT 0.94 70.00 0.85 0.99 0:01 0.98 75.00 0.82 1.03 6.01 1.02 go -Go 0.80 1-07 0.01 1.06 85.00 0.75 1.07 0.01 1.05 90.00 0.70 1.05 0..01 1.04 95.00 0.65 1.03 0.01 1.02 100.00 0.60 1.00 0.01 0.99 105.00 0.S8 1.01 0.01 0.99 110.00 6.55 1.01 0.02 1.Do ..................................................... THE REQUIRED POND SIZE v 1.058181 ACRE -FT THE RAINFALL. DURATION FOR THE ABOVE. POND STORAGE- 80 MINUTES s unofficial copy was downloaded on May-10-2017 from the City of Fort Collins Public Records Website: http://Citydws.fcgov.com additional information or an official coov. Dime contact Citv of Fort Collins Utilities 700 Wood Street Pon Collins. CO 80524 USA I H it Fort Collins Streets Facility Composite Rational Method Runoff Coefficient for Water Quality Pond 6 Designer. SLG Basin a Jac) a otes = From Current Report 0-2 0.21 0.25 0.05 " 0-3 0.54 025 0.14 0-4 0.13 025 0.03 " 0-5 0.11 0.25 0.03 •' 0-6 0.11 0.25 0.03 A-3 0.13 0.35 0.05 From Muller Engineering Report 4B-1 1.23 0.95 1.17 H-1 0.93 0.41 0.38 H-2 0.66 0.75 0.49 •' H-3 0:48 0.95 0.48 H-4 012 0.54 0.14 •• H-5 1.87 0.95 1.78 " Pond 8 0.85 0.26 021 This indudes 0.18 ac from original 1993 H Basin Total: 7.52 4.95 Composite. C -tor. Basin: 0.68. "Basim A. B. 0-2. and H from the 19M OrainaM E WW Storm Water Quality Study were divided fuller for devaWnterd design. 183-047 (Fort Collins) �J _ is unofiicin] copy was downloaded on May-10-2017 from the City of Fort Collins Public Records Website: http://citydms.fcgov.com w.additionat information or an official.comv. please contact Citv of Fort Collins Utilities 700 Wood Street Fort Collins. CO 80524 USA I Jl vaaasaaaaax-xxzxaxxsa�aaaaaaa.-eaaaaaaca_-xxxxacevaaaaxaamaaaeanavax_mn_a DETENTION POND SIZING BY FAA METHOD Developed by Civil EMS. Dept., U. of Colorado Supported by Denver Metro Cities/Counties Pool Fund Study Denver Urban Drainage and Flood Control District, Colorado aaaaaeaeaaaaaaaxxo_-xaxxaxsasaxaaaaaa-e_--aaaaxxsxaaxxaxxcxxxxxxx�aneax-_anx USER -Kevin Gingery....: .......................................................... EXECUTED ON D6-23-1999 AT TIME 15 43:53 PROJECT TITLE: Fort Collins Streets Facility • Water Duality Pond B DRAINAGE BASIN DESCRIPTION BASIN ID NUMBER a 1.00 BASIN AREA (acre)- 7.52 - Changed from 1993 report due to inclusion of railroad swale and. RUNOFF COEF - 0.66 sub -basins 4B-3 and A-3. Runoff coefficient calculation on previous page. DESIGN RAINFALL STATISTICS DESIGN RETURN PERIOD CTEARS) n 106.00 INTENStTY(IN/HR)•DURATIONCMIN) TABLE IS GIVEN DURATION 5 10 20 30 40 50 60 80 100 120 150 180 INTENSITY 3.2 2.5 1.8 1.5 1.2 1.0 0.9 0.8 0.6 0.5 0.4 0.4 POND OUTFLOW CHARACTERISTICS: MAXIMUM ALLOWABLE RELEASE RATE a .1 CFS r Considered SM17 enough to provide. for approxfR¢tely - OUTFLOW ADJUSTMENT FACTOR a 1 - 40-how detention time and conservative pond size. AVERAGE RELEASE RATE a .1 CFS AVERAGE RELEASE RATE - MAXIMUM RELEASE RATE * ADJUSTMENT FACTOR. COMPUTATION OF POW SIZE RAINFALL RAINFALL INFLOW OUTFLOW REDUTRED - DURATION VOIlik VOLUME STORAGE RIIRAE _IMTEIISITy IRCR/RR ACI -FT ACRE -FT ACNE -FT 0.00 0.00 0.00 0.00 0.00 5.00 3-7A 0.11 0.00 0.11. 10.00 2.50 D.17 0.00 6.17 15.00 2.15 0.22 0.00 0.22 ZO.00 1.80 0.25 0.00 0.25 25.00 1.65 0.28 0.00 0.28 30.00 1.50 0.31 0.00 0.31 35.00 1.35 0.33 0.00 0.32 40.00 1.20 0.33 0.01 0.33 ' 45.00 1.10 0.34 0.01 0.34 50.00 1.00 0.34 0.01 0.34 55-AD 0.95 0.36 0.01 0. _. 60.00 _. .86 .. 0 3 0.01 ..35 0.3 6500 6.88_ 0.39 0.01 0.38 MOO D.85 6.41 0.01 0.40 75.00 0.82 0.43 0.01 0.42 80-11 0.80.. 0-44 0.01 0.43 85.00 0.75 0-K 0.01 0.43 90.00 0.7D 0.43 0.01 0.42 95.00 0.65 0;43 0.01 0.41 100.00 0.60 Oc41 0.01 0.40 105.00 0.5B 0.42 0.01 0.40 ' 110.00 0.55 0.42 0.02 0.40 ..................................................... THE REQUIRED POND SIZE _ .4301541 ACRE•FT THE RAINFALL DURATION FOR THE ABOVE POW STORAGE- 80 MINUTES 1 s wofficial copy was downloaded on May-10-2017 from the City of Pon Collins Public Records Website: hap://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins. CO 90524 USA 1 1 1 1 1 FortCollins Streets Facility 183-047 yyater Quality Ponds A & B Volume Calculations (Fort Collins) Designer. S. Gentry 1. Water Quality Pond A Contour Area MA2) Volume W3) Volume (acdt) 46 350.00 18993.49 47 52350.00 27070.01 47.5 59; .00 Total: 46063.51 = 1.06 Needed Volume: = 1.06 Surplus = 0.00 Water Quality pond A volume Is adequate for the Wtuat(on. IL Water Quality Pond B _Contour Area MA2). _.Volume (!t•3). volume (aeit) 47 1.00 9184.95 48 27388.36 14201.45 48.5 29429.68 Total: 23386.40 = 0.54 Needed Volume: = 0.43 Surplus = 0.11 Water Quality Pbnd B volume Is for Me situation, is unofficial copy was downloaded on May-]0.2017 from the Ciry.of Fort Collins Public Rtconls Website http://citydocs fcgov.eom� or additional infotmationw an official copy, please contact City of Fort Collins. Utilities 700 Wood Stet Fort Collins, CO 80524 USA Fort Collins Streets Facility 163-047 Detention Pond Volume Calculations (Fort Collins) Designer. SLG The survey certification after completion of 1993 construction shows an increase in contour size from what was planned. Therefore, the Volume for the detention pond was recalculated. Contour Area (it42) Volume MA3) 44 9585.12 28SM40 45 53496-61 85167.48 46 121413.10 Total: 113742.88 = Volume (aaft) 2.61 Top of pond is 4947 feet. The emergency overflow weir is set at feet Setting the rneximum water surface elevation for the 100-year storm, at 4946 That allows for 'one (1) foot of freeboard. Volume Available for Detention: Pond Volume (ac-ft) Water Quality Pond A 1.06 Water Quality Pond B 0.54 Detention Pond 2.61 Total: 421 Volume needed for detention Is: 4.18 ac-ft Volume avaAable for detention is: 421 ac-ft Surplus of 0.03 ac-ft Current detention pond volume in adequate for the situation. d his unofficial copy was downloaded on May-10.2017 from the City of Fart Collins Public Records Websitei http.,/IF4dms.fcgov.com or additional information or an official copy, please contact City of Fon.Collins Utilitics 700 WoodSttect Fort Collins, CO 80524 USA APPENDIX C ' DRAINAGE INFORMATION Back Out of Original Seat -Brown Impervious % from C Value Drainage Exhibit Runoff Computations C M a Y Yl V t0 L 0 V !'1 C 9 O 9 a Y amo aMo�� W 4! N L I I I I N 3 e O N O N J 7 O CL Y W m a m E a m V N N C d v a v v 0ua aa2e �o uO1i a00o� C C Ol V1 M Ifl pp N �••I rl N d Of m m .r A C m •� II 11 N O r o N O a n Z J o N � = aCL N _ m m E a y N 0 0 v N a N N v a Ou¢ \Q2e m r 0 0 a O 3 O H Y V C m U N d O� 0 O 0 N w 00 O n t7 n'i In O d r N I I N G o O n o N 0. w a az c - O� a m m E a m s r p m N a N v O• E i u¢ a a X a v S0 Y u CrU! 3 O O r Do ,m � m N d G vi In Ir m m ao m (n m cn rl N C e0 O d ti H I I N J C O j N O O > O J CCL m a 0 U Q Q Q a' 0 m C L 7 s r 0 u m li• N C C A O a a O it N a N J 0 m m CL E a m o m �a v a a E u 3ua aaa� AHIvM>ip)AVL1slNeu;v)GNF rAF)v/AMClrEF.� III I 1I I III _ _ __ p I I I ® q -----1---+,-- - TV Al / V/\ � / LOT IA.AREPIAT OFA ;® { \\ •b' / PORTION OF LOT6 1 AND 2. mj \ \ I / CAST VINE bTREE15 FACILITY I , / PAD..MAJOR AMENOEO 11 !® J / FINAL PHASE TWO FlNAL II , I fi —a--i_--- I 1 \ \---------J — `_--------- — — — \\ -- \\ Lr J ADs ____ __ \ \ w UE I /F15 I YIRAtYO 8Y[.I51 qE _-__—_—__—_•_ Ire-m.x /f as A aJ1 /f /Aq0 /}RACTA. EA6F VINE 6TAEETS FACILRY f.EDRAIAGE DACCESS EASEMENT / / 5D s � Y PVC rvP) /EIIO.0 A rRUI / 1MCT A RANQT mN1ADE AID / EA AC24 N10111f1YT ,. � AW If P1 .aD as DIwE . b.5 W, m0� 51-0 5t ) 50.5 rL WP eDm 'a' PK f 15rN.5 rtM wE I.SB n)z er nFlAx - ------------------ I M. _ ro arx zTMET Imo: c DCo bns _ A,- Park PlrNling d Devebpnern � t16 NwN MMm Stew Fwl Coie. Lobwb B05)1 - I wsroulalM :•M �NpmMenq PRELIMINARY NOT FOR CONSTRUCTION r•, I MIEITY NOTfIGT10N CFNIER OF COLOPADO 1-800-922-1987 on 534-6700 WOW cu.)wastewm NbVAM MTWSYOUDN9R.nE.w E* vL1 rDP mE �ulLies""' 0 Yw Z� 0�W _O �z N5O L Z w > �o p0 F— DO U0 LL PROLNO. 1TSS4112-92 DRAWN: W CHECKED. MPO APPROVED DATE. 0920ROIS REVSIONS'. LEGEND LEI TABLE ( NEW IMPERVIOUS AREAS) LEGEND MPERvn)us AtFATRFarm sr IRE nMT»ExrwADD1NcamAwEwrRAL )PPucAA[Area lCAkrercldmpN9D1aR LGeem papoeeE NTVBASIN eoEFFlUEurUGottn ST K E9VBHIj fnqM I11mslTnr:wwBASIC FORRrynM Mnlmvn FnoenrvaArmlDhTi Y[E 12M1 w1\ w �. ISSUEDISSUED DEVELOPMENT MFEPVIp1s Ar84TwEATm att b' FMT C.1 C0.pIAD0 REVIEW Ikw P&Avp ArN (Pan WMII D.B13 F9. E Br GRl4 BUFFER INAtX9 DESWN POEM care Area Ua..p EDI IP Wamrn MenarGla vl 2MY Y l UTILITY PLAN APPROVAL 54ewMts KMass BI/bl 7.116gE MPFnvIwsAAEn DBUNINGTO OETENTpN iONO )a9 .nPTaT6 Area rrmleE b/tO I3,B11q L M•ALK NQF TREATEp BY L1Dr pNANAGE 9A51N GO 20 O 40 80 APRtGYFe: waam w= SHEET TINE' ArWel%On3lw Tnerely uo DRAINAGE EXHIBIT TOAwnA9oDSAREAORAINMG EA IAAARcoNTOVR SCALE: I"=4p' ry eeuauv ewn. IwAUCa NOT TREA)ED W UW GE(%♦D Bc vs YFERVIpJv /JIEPNOi ORAMINGTO E%MNORCONrIXR almis\y. yprrr t oEa1Fn BY. SCALE: 1'4V oElENnpu PGNo mm PROPosmlugRcoN)ouR M•AUtSNUT TREATED eY uDOR FORxoI DEGan Br: SHEET MEMBER -lOO� IgOPOvm MINIXtCOwFGM PNtS. RRt1Or Wi rD TREATI.tENr ArsEn GRAYEEI:m scLow=�FETvsGrxcAce CNEo®Bc� a: OCOO BY. orwlwer... n.l.ee M7< \! § ! B � --- � 1-3 -. :go , kk G : ; !ƒ � .#( . � k 2 2 I§ !8 }» �§ B `• f |}` �2 | � !#« § , f«+ mm | - @@ k§S2o <; \ z z 00 F OH °a$a N Y W R 0 m m „ o° s O in (.l O W c E � c a tt O � o ui a U N N U o 0 Q U m A 0 2 Qo y�y N 6 m rw W a a' a m me rn 8 � O N N U ap ti n N C_ 0 U 0 0 LL 0 U E O m F y t CD v � U N C•J f0 °7L•m L C4� C g `+ C CL 45 u n u OU.iI ; !. f \! | A a - 2; $ ;! k{ & )- -°� � ! 7E aE( )/ » ;,... §06222; Q Y 6 d N � ra9L E 0 of e Y a1d O S;�xv N O= C p^ E-^ m (V O n W J N n =w H C d N Q G C O O W t 5 n 0 N 0 N F � w 5 €2n m n ' E = m N m m N — " c5'z a - rj _mn c C O V � «6 3. m u V m N N Q 3 m am m Soon E U ■ , } 2 ~#{G i ;!- 0 26 �2 2 ® |f !v ! � (2� §( � ( \ § § k 0 ;cr §z §8 |o ti§ B §9 r» {$ f(t« | -�- k |2 \ �-Z K : #epLIS � ,-- „ f!# a �9- q7° E f! B■)2 \ i / / k LL . ■ §_ )� §� � §_ IC) 20 ■W o\ q3 �—/ \ § $) 2 In 7 « - ]6a2 / ¥ \ / B�\ �\kM � \m(� § § a §» ® CC cc �#!� k � £ 7 , §§ ® f / !§ i / f <in / \ % APPENDIX D POND CALCULATIONS Actual Existing Pond Volumes based on 2017 Topographic Survey Proposed FAA Detention Sizing with `-`New" City Rainfall Overall WQCV Required for Both WQ Pond.A & B Proposed Volume Calculations (Detention and Water Quality Pond A) ' Orifice Plate Sizing for 9.3 CFS Spillway Calculation Detention Pond Drain Time Cb 11 u 1 u 1 N Ol � vi r y ocs W m y O m an OO. L C a + j -0y a G CO rk i s �+ > v 6 _a 41 �i C c u 'm > g N j m O.Fo ozPt p a UU C O O O O O OR H Q N O O O O O O O O O O O O O O O O O y mN O Z O O O O O O O O O O O O O N O W m 0 0 0 0 0 0 0 U W C D) m' N H O LU ONO u[ WH R M In r R. In 0 �[J F r W O n n O C! 060O NN a<a44444 ON wM'NNN m =° '� OOOOOoo°i�mm� ci, U? m0I m 6 0 0 0 0 0 W m W T O N M O O O O O O NNN N m.. G C G G C O C C O O O O G �U„-_m W C n O gg a r r OWN W riv��v�ao-, yav ��NHOHOtn Oi(f W O� Mu]r tG W hr M00)00000 rR W v vva��aa ain W W In IL) 10 '� Oooc7n�ms'i�mn t/1 oo W m W Mr-: W o N v, q c Rom' LUMOy OrosOONm t O W V �¢� NNN W OM IfiNO m .� ti iG vaooavveeu��n tG 1� n OOOi OOOOO �n J JyJ J J as 0)(n W W O a E O O M Y Q a p w W cc U) m Interwest Consulting Group DETENTION VOLUME CALCULATIONS ' Rational Volumetric (FAA) Method 100-Year Event LOCATION: STREETS PARK -1999 PONDSIZING WITH NEW RAINFALL PROJECT NO COMPUTATIONS BY: LAJ DATE: 8/10/2018 E a ions: Area trib. to pond = 29.47 Developed flow = QD = CIA C (100) = 0.79 Vol. In = Vi = T C I A = T QD Developed C A = 23.3 Vol. Out = Vo =K Oao T Release rate, Qno = 9.30 storage = S = Vi - Vo K = 1 Rainfall intensity from City of Fort Collins lDF Curve with updated (3.67") rainfall acre acre cfs (from fig 2.1) Storm Duration, T (min) Rainfall" Intensity, l (in/hr) Qo (cfs) Vol: In Vi Vol. Out Vo (ft) Storage S (ft) storage S (ac- t) .5 9.95 231.6 69495 2790 66705 1.53 10 7.77 180.8 108487 5580 102907 2.36 20 5.62 130.9 157027 11160 145867 3.35 _30_ __ . __ 4.47 104.0 _. _ 187253_ 167_40. 170513_ _ _. _ 3.91 40 3.74_ 87.1 208969 22320 186649 428 --50 3.23 75:3-- 225862 -27.900' 197962-- --4:54 60 2.86 66:6 239682 33480 206202 4.73 70 2.57 59.9 251382 39060 212322 4.87 80 2.34 54.5 261536 44640 216896 4.98 90 2.15 50.1 270515 50220 220295 5.06 100 _ _ _ 1.99_ _ _ 46.4 .278573_ _ _. _ 55800 222773 --- - -- -.110 1.86: .43.3. 285888 -61380 224508 .5.15 -120- - 175 - 40:6- 292591 _. - - -66960 - 225631 - 5i18 130 1.65 38.3 298783 72540 226243 5.19 140 1.56 36.3 304540 78120 226420 5.20 150 1.48 34.4 309924 83700 226224 5.19 160 1.41 32.8 314983 89280 225703 5.18 170 _ 1.35 31.3 319756 94860 224896 5:16 180 1.29 30.0 324277 100440 223837 5.14 190 1.24 28.8 328573 106020 222553 5.11 200.._..._ __ 1.19_ _ _27.7 332667 111600. 221067 _ ___ ___ _5:OZ__ _. 210--- _ ._ 1.15_ _ - .26.7_ _ 336579. _117180. _ 219399. 5:04. Required Storage Volume: 226420 ft 5.20 acredt 08-10-18STREETS PARK POND_ LAJ.xis,FAA-100yr (A-E)) Design Procedure Form: Extended. Detention Basin (EDB) - Sedimentation. Facility LOCATION: Streets Park - Overall WQCV Required for Both WQ Pond A & B PROJECT NO: COMPUTATIONS BY: LAJ DATE: 8/10/2018 1. Basin Storage Volume A) Tributary Area's Imperviousness Ratio (61a/l00) Is = 73 i = 0.73 B) Contributing Watershed Area (Area) A = 22.37 acres C) Water Quality Capture Volume (WQCV) WQCV= 0.29 watershed inches (WQCV = 1.0' (0.91 ' 13 - 1.19' iR+ 0.78i) ) D) Design Volume: Vol = WQCV/12' Area "1.2 Vol. = 0.65 ac-(t \ !§ oil! • !I\M. tic ! ! |f\ )!)}lit ! , /! !}! !■!!!!!!!!!!!§! ff; !!■-a■■;.SEES !:_ •||�!]!!|| )|; ■¥==�a�w�;m,� —_ ,�lF!! ■�;.I.; » _��,��rEBm� |E Tf«;;;;;;;;;; LOCATION: PROJECT NO: COMPUTATIONS BY: DATE: STREETSPARK LAJ 9/20/2018 DETENTIONPOND 100-yr Event, Outlet Sizing Submerged. Orifice Outlet: release rate is described by the orifice equation, 4, = C,A,s4rt( 2g(h-E,)) Where O, = orifice outflow (cfs) C. = orifice discharge coefficient g = "gravitational acceleration = 32.20 fVs A, = effective area of the orifice (W) E, = greater of geometric center elevation of the orifice or d/s HGL (ft) h = water surface elevation (ft) % = 9.30 cfs outlet pipe dia = D = 18 ;0 in Invert elev. = 46:20 It (inv. "D" on outlet structure) E, = 47.50 It (downstream HGL for peak 100 yr flow from FlowMaster) h = 50.23 It - 100 yr W SEL C, = 0.65 1 solve for effective area of orifice using the orifice equation A, = 1.079 ft` = 155.4 in` orifice dia. = d = 14.07 in Check orifice discharge coefficient using Figure.5-21 (Hydraulic Engineering) d/ D = 0.78 kinematic viscosity, v = 1.22E-0.5 ftz/s Reynolds no. = Rea = 4Q/(ndy) = 8.28E+05 C, = (K in figure) = 0.65 check A, = 1.079 h ` = 155.38 ink Omax = 9.30 cfs 1 orifice - 100yr, 69-20-18 STREETS PARK POND_LAJ:xls Detention Pond Emergency Overflow Spillway Sizing LOCATION: STREETS PARK PROJECT NO: COMPUTATIONS BY: LAI DATE: 8/13/2018 top of berm Equation for flow over a broad crested weir _ Q = CLH3 z 4 H spill elevation where C -weir coefficient = 2.6 L H = overflow height L = length of the weir The pond has a spill elevation equal to the maximum water surface elevation in the pond Design spillway with 0.5 ft flow depth, thus H = 0.6 It Size the spillway assuming that the pond outlet is completely clogged. Pond Q (100) = 118.0 cfs (peak flow into pond) Spill elev = 50.30 ft (design elevation) Min top of berm elev.= 51.20 Qpeak @ 25 minutes Weir length required: L = 98 ft Use L = 100 ft v = 1.90 ft/s Note: Spillway Peak Flow (Qpeak) was determined by the following: Total Length of Basin = 2700' approx. Urbanized Check: (L1180) +10 (2700/180) +10 = 25 min. spillway, 08-13-18 STREETS PARK POND_LAJ.xls I Stormwater Detention and Infiltration Design Data Sheet ' Stormwater Facility Name: Streets Park ' Facility Location &Jurisdiction: Fort Collins, CO User (Input) Watershed Characteristics ' Watershed Slope = 0.007 R/ft Watershed Length -to -Width Ratio= 6.00 UW Watershed Area = 24.97 acres Watershed Imperviousness= 54D% percent Percentage Hydrologic Soil Group A = 0.0% percent Percentage Hydrologic Soil Group B = 0.0% percent Percentage Hydrologic Soil Groups C/D = 100.0% percent User Input: Detention Basin Characteristics WQCV Design Drain Time = 0.00 hours 1 t 1 After completing and priming this worksheet to a pdf, go to: ' httos://maoerture.digitaldatasemices.com/evh/?viewer--cswdif. create a new Stormwater facility, and attach the pdf of this worksheet to that record. ' Routed H dro ra h Results Design Storm Return Period = Two -Hour Rainfall Depth = ' Calculated Runoff Volume = OPTIONAL Override Runoff Volume = Inflow Hydrograph Volume = Time to Drain 97%of Inflow Volume = ' Time to Drain 99%of Inflow Volume = Maximum Porting Depth = Maximum Ponded Area = Maximum Volume Stored = ' 09-20-18 STREETS PARK DRAIN TIME.xlsm, Design Data User Defined Stage Iftl User Defined Area Iff^21 User Deed fin Stage Ift] User Defined Discharge Icfs) 0.00 0 0.00 0.00 0,30 1,218 4.00 9.30 0.80 8,312 5.10 118.00 1.30 21,334 1.60 30,795 1.80 37,534 2.30 54,994 2.80 73,961 3.30 95,407 3.60 109,321 3.80 160,821 3.90 165,681 4.00 167,951 4.10 175,319 4.30 48,465 4.80 59,776 5.10 0 WQCV 2 Year 5 Year 30 Year 25 Year 50 Year 100 Year 0.53 0.98 1.36 1.71 2.31 2.91 3.67 0.001 1.048 1.759 2,431 3.687 4.851 6.462 0.001 1.047 1,759 2,430 3.687 4.850 6.453 1 4 5 7 8 10 11 1 4 6 7 9 10 12 0,01 1.78 2.28 2.65 3.20 3.62 4.01 0.000 0.845 1.241 1.562 2.092 2.612 3.863 0.000 0.547 1.065 1,583 1 2.597 1 3.561 4.912 n acre-ft acre-ft acre-ft lours lours 1 acres acre-ft 9/20/2018, 11:35 AM Stormwater Detention and Infiltration Design Data Sheet RO soy UT 125YR OLFr��T' 0 ZYR IN -- In —�---- CCCC�C got WIN! ------ -= NEIniN■■■n�i ■■nin w ■■■� lm■■■1iiii ■■ �W ■■■1111 1 u i,��► ■ ■■■1ini 11101 1 09-2048 STREETS PARK DRAIN TIME.xIsm, Design Data 9/20/2028, 11:35 AM APPENDIX E ' LID INFORMATION Drainage Exhibit Trickle Pan for New Parking Area Rain Garden Calculations E II sysF aAbawe ragas � _ — r _ __ i J I I I rWSEL=b02 einnces E LOT2A,AREPLATOFAPORDONOFLOTS I 1 \< \� AND 2, EASTVINE STREETS FACILITY P.U.O., f I _ D Eii4c \ \ MAJOR AMENDED FINAL, PHASE TWO FINAL / h 1 \ I I 11 \ J I I r tins Sm 031 /E I 1 ' I I LD+ove ott• l � I ' �- - ._- Ir BEP - - NSNMexr oweGDw - I -----1---4�slEa�iT - � -� -- • / �- ^r� SLa Sax � -- / 1 Park Planning A Devebpment 215 NoM M.SVeat Fat C.tr,Co .NX21 .t-. 1e[ 9T1221.EM0 Rl-y+ra*MnPem.N I PRELIMINARY �. NOT FOR CONSTRLMDOR y I l ni f?: A,EASTYINE STREETS FACILITY i / P.Ua.. DRAINAGE AND ACCESS EASEMENT 0. SIW= 91rLfaT I - / - , - \ \ - ll TIiR6NdTT9 1 M 1 il3 ! TT vv I wlTurm ARB! % F�asz_a" u n I 1 LOT I A. A REP PORTIOEAT OFA ; ® ( �' I 1 /� V I AF mm l ACCS4 MAallIIT M1y PORTION OF LAl81 AND2. \\\\/ * / I I( / RTO — Irm / EAST .O.,M REEfSFACILTTYI i WWW PU.D, MAbNAMENOED — 3 .._ �______ �00 / FlNAL,PNASETWO FNAL © - > / � \ I / Y CART O� 40, _ - _ _ RAR FW vrt PlvllvmcCN- ------------- r P1C LID TABLE ]5%O Sne Treelmem d Nev ImPe .a b 10 (W Paers PrtWUU) Ne+ M[ervous Area d mpeeas area LeMem gryvuE cmCleons III pepgect cmeeoml t6 B51 ep. I RO,N, U M... Imiemuls A� I. M T Id 1264I,t New P2MInV Mea (Ran Gatlenl 3815.1 C e AI Danlry Easl PlaygWGm l a M ZINO N t SHa Nl(Gl B" ].]Siset Td' M� Area irtvlM Ey LID 136T0 se F AcWel %On41Y Tma Wd q UD M% II LEGEND (NEW IMPERVIOUS AREAS) MNGATIs TREATEDBY pAM GARCENNEN PARKING) MPE]MOD6 AREA TREATED BY PIAYGR W NO MEDIA PIAYCR W ND) MPERVIODS AREATRFATED BY GPT55 BUFFER fNAllt9 3:" MPERNWSARFA DRAINNGTO O OINON POND (WALK NOT TREATED BYt1D1 BAPERYAREADRAMeLC TOWOPO.POND2 NIALKS NOT TREATED BTUD) MPERNOIIS AREA NOT IXU W ING T V DEIENTIONPOND M14Al NOT TREATED BY UD OR FOR WO) LIOTREATMENT PRFA (GRAVRBED BELOW SM'ETYSIIRFACIM LEGEND DO1 -$IN OESONPTON L25 G 61SNCCEFTIGENiI1 WYW SASINPAEA ® DESIGN POINT DRAINAGE ROW ARROW ORNNAGE BASIN � � � _ BONIDARI EY NAIORGONFQIR — i.. ESMINORCANiWR yam. PRCWOSEO MPJOR CAMOUR 5N1 II_ PRO .DMINOR GONTOLN Be.n 1 / / t / IX / AGO I / It PiFF -w. 1ov aal' D.N.O 40 20 O 40 80 SCALE: I"= 4O' TO BM SNOT_ OTY U `Q T CIXLINS. C2.t UTILITY PLAN APPROVAL T. An DIPm BY: as a avrza.m uvn BT 4i6Y1/A1FP VARY BY: suss • la�anol SY. Ause Nava BY: wwdaExrA wYoan CALL UTLRY NOTIFMMN CENTER OF CDLDRA00 1-00D-922-1967 d+ 534-67DO cNL]waress MS xIM'F"CE B6tl£ YW D6. WLE pl F]IGVI.iE PW iKE � Vi UIX6f�Ap1p1ND II I 0 N VJ W Z F �w JO Q� OJ I d� 00 f_ d 0� in w° OZ UU I�' o LL J O Q _ I LO m �o .p PROD.NO. 1165012-92 DRAWN: LN CHECKED: MPO APPROVED: RATE: 09/20/201B REVISIONS: STREETS PARK ISSUED FOR: BASIC DEVELOPMENT REVIEW SHEET TITLE: DRAINAGE EXHIBIT SCALE: 1'=40' SHEET NUMBER 1 4' TRICKLE PAN Cross Section for Triangular Channel - 1 Project Description Flow Element: Triangular Channel Friction Method: Manning Formula Solve For: Normal Depth Section Data Roughness Coefficient: 0.013 Channel Slope: 0.35000 Normal Depth: 1.65 in Left Side Slope: 12.00 Wit (H:V) Right Side Slope: 12.00 f /ft (H:V) Discharge: 0.26 ft31s 1.65 n vi L H 1 Worksheet for Triangular Channel 1 roject Flow Element Triangular Channel Friction Method: Manning Formula Solve For: Normal Depth Channel Slope: 0.35000 % Left Side Slope: 12.00 Poft (H:V) Right Side Slope: 12.06 ft/ft (H:V) Discharge: 0.26 ft /s Normal Depth: 1.65 in Flow Area: 0.23 ft' Wetted Perimeter: 3.32 ft Top Width: 3.31 R Critical Depth: 0.12 It Critical Slope: 0.00625 ft/ft Velocity: 1.14 ft/s Velocity Head: 0.02 It Specific Energy: 0.16 ft Froude Number. 0.76 Flow Type: Subcritical Downstream Depth: 0.00 in Length: 0.00 It Number Of Steps: 0 Upstream. Depth: 0.00 in Profile Description: N/A Profile Headloss: 0.00 ft Downstream Velocity: 0.00. fus. Upstream Velocity: 0.00 R/s Normal Depth: 1.65 in Critical Depth: 0.12 ft Channel Slope: 0.35000 % Critical Slope: 0.00625 Wit I I I Design Procedure Form: Rain Garden (RG) 11 9hae11 nl P Daaignar: mo Company: O.10: August 13,=18 Project: Streets Park - Basin B Parking Spaces - Rein Garden Location: 1. Basin Storage Volume A) Ehac1IVB Imperviousness of Tdbulary Area, I, I„ = 59.0 % (IM If all paved and rooted areas upstream of rain garden) B) Tdhtary Area's IMMINIGusness Ratio (i. IJ10g) i. 0.500 C) Water Quality Capture Volume (WOCV) for a 12-hour Drain Time WOCV= 0.19 walerehed inches (WOCV=0.8'(,11. 19.12+078'1) of Contributing Waterenad Area including rain garden areal Area = 1 454.9114 , it E) Water Quality Capture volume(WOCV) Design Volume Vwom= 22686 cult Vol . (WOCV / 12) - Area R For Watersheds Outside of the Denver Region, Depth of or =in Average Run." Pmoudng Storm G) For Watersheds Outsde of the Denver Region, Vwwv omen cuff Water Quality Capture Volume (WQCV) Design Volume H) User Input of Water Quality Capture Volume(WOCV) Design Volume Vwocv user- cuff (Only if a ifi erent V ICI Design Volume Is desired) 2. Basin Geometry A)WQCV Depth (12-inch meaam.) Dwocv- 10 in B) Rain Garden Side Slopes (Z . A min., hohz. dial per unit vertical Z. 20.00 his (Us.'9' d ran garden has vertical walls) C) MiMmum Fiat Surface Area A a, = 15057 se It 0) Actual Flat Surface Area A.,=,. = 18666 so, It E) Area at Design Depth (Top Surface Area) Arm = 40844 W It R Ran Garden Total Volume Vr= 24,795 cu 11 IV, (IArm+A....J / 2)' Dean) 3. Growing Media 4, Unde20ran System A) Are u etworams, provided? B) Underdraln system orifice diameter for 12 hour drain time i) Distance From Loxest Elevation of me Storage y= e Volume 10 In. Center of the Orifice III Volume to Drain in 12 Hours Vol,2= WA cu 0 III) Orifice DlamMar, 3n8' Minimum D., - WA in Design Procedure Form: Rain Garden (FIG) Shost1 oft Designee LAJ Company: Data: November 8, 2018 protect: Streets park - Playground Gravel Bad Below Safety Surface Location: 1. Basin Storage Volume A) Effective Imperviousness of Tributary Area, I, I, = 12.0 (100%It all paved and cooled areas upstream of rein percent B) Trlbulary, Area's Imperviousness Ratio (I a If100) 0.120 C) Water Quality Capture Volume (WOCV) for a 12 hour Drain Time WOCV= 0.06 watershed inches (WGCV. 0.8' (0.91.1'- 1.19' lea 0.78 - I) D) Conblbulirp Watershed Area including rain ga den area) Arse - 15.664 of 8 E) Water Quality Capture Volume (WOCV) Design Volume V-,, at cub Val . (WOCV 112) - Area Required WOCV F) For Watersheds Outside of the Denver Region, Depth of or in Average Runoff producing Storm G) For Watersheds Outside of the Denver Region, VwxvmaL w It Water Quality Capture Volume (WOCV) Design Volume H) User Input of Water Quality Capture Volume(WOCV) Design Volume V.oc com cub (Only If a different WOCV Design Volume is desired) 2. Basin Geometry A) WGCV Depth (12-inch ma.im,m) D.aae a 0.25 In Depth provided by the curb around the perimeter of the B) Rain Garden Side Slopes (Z.4 m i hodsdisc per unit vertical Z - 0.00 it I8 p)aygrcund area (Use -0- If in gardan has vertical wells) C) Mammon on Flat Surface Area A,,,, - 54 soft D) Aclual Flat Surface Area AA., - ININ sp h Playground Area E) Area at Design Depth (Top Surface Area) Alm - M06 sg0 Playground Area F) Rain Garden Total Volume VT- 175 cu h (VT- ((Arm • A,r..) / 2) - Depth) 3. Goosing Media 4. Underdmin System A) Are underdmins provideol? B) Underdraln system odlke diameter for 12 hour drain nice 0 Distance From Loweel Elevation of the Stooge y = ft Volume to Me Center of the Orillce ill Volume to Drain in 12 Hours Vol,;.. INA cu It ill Chfire Diameter, 3M' Minimum Do - N/A IAPPENDIX F STANDARD OPERATING PROCEDURE (SOP) F I Plaveround Surfacing Maintenance. Plan Routine Maintenance Table (Summary adapted from Chapter 6 of UDFCD, Volume 3) Required Action Maintenance Objective. Frequency of Action Debris and Remove debris and litter from the Routine - Including just before Litter Removal infiltrating surface to minimize clogging of annual storm seasons (April and the media. May), end of storm season after leaves have fallen (October), and following significant rainfall events. Sediment Removal Maintain adequate infiltration rates to Non -routine - Maintenance and Media drain the playground surfacing Within 24 activities to restore infiltration Replacement hours. Upon replacement of EWF and/or capacity of playground surfacing clogging is observed.. Inspection of the will vary With the degree and geotextile fabric and drainage gravel below nature of the clogging. The the EWF should be performed. If either frequency of media replacement item is preventing proper infiltration, it will depend on site -specific should be replaced per design characteristics that have the specifications. potential to clog the playground _. surfacing and drainage gravel. Replacement of Maintain a level play surface with raking of Non -Routine - As needed and Engineered Wood existing EWF and add additional EWF as inspect EWF conditions at least Fiber (EWF) necessary to achieve a level surface and twice annually following proper depths. Where playground precipitation events. equipment is less than 4 feet in height, the minimum EWF depth required is 8 inches after compaction. Where playground equipment exceeds 4 feet in height, the minimum EWF depth required is 12 inches after compaction. Inspections Determine if the playground surfacing area Routine- Inspect the. infiltrating is providing acceptable infiltration, and surface at, least twice annually outlet structures are not obstructed. Check following precipitation events. for erosion and repair as necessary. Check for obvious problems during routine maintenance visits, especially for plugging of outlets and erosion. Pl;tveround Drain Pipe Lines Maintenance Plan Routine Maintenance Table Required Action Maintenance Oblective. Frequency of Action Debris Removal from Inlets and Catch Basins Remove debris and.trash from inlets to prevent:them from continuing downstream or clogging and reducing the flow capacity of the system. Non -routine — Remove debris as needed after storm events or seasonally such. as during the Fall with heavy amounts of leaves and twigs entering the system. Debris Removal from.Storm Ensure the pipe systems function Non -routine — Pipe cleaning Iis Pipes as intended. Reduced capacities recommended as needed based in the pipes will cause the system on the results of inspections or to backup and increase the when the system is no longer frequency of surface flooding able to -regularly convey routine that could damage property. storm flows from the site. Inspection Use a video camera to inspect Routine —Visually Inspect pipes the condition of the storm drain and inlets at least annually or pipes looking for sediment after major storm events. Every buildup and structural integrity. 2-5 years the pipes should be Clean out pipes as.needed. If the inspected with a video camera. integrity of the pipe is compromised, then repair the damaged section(s). Bioretention/Bioswale Routine Maintenance Objective of grasses and weed Frequency of Action Lawn mowing removal to limit unwanted vegetation. Routine — Depending on aesthetic and vegetative Maintain irrigated turf grass as 2 to 4 requirements, planting scheme and cover. care inches tall and non -irrigated native turf Weeds should be.removed before they flower. grasses at 4 to 6 inches. Remove debris and litter from Debris and litter removal and snow stockpiling bioretention area and upstream concrete forebay to minimize clogging of the.sand media. Remove debris and litter from the pond area and outlet orifice plate to minimize clogging. Remove debris and fitter from curb channel and sidewalk chase outlets adjacent to pond if applicable to minimize clogging. Avoid stockpiling snow in the bioretention area to Routine — Including just before annual storm seasons and after snow season (April or May), end of storm season after leaves have fallen, and following significant rainfall events. minimize clogging from sediment accumulation. Inspect detention area to determine if the sand media is allowing acceptable Inspections Infiltration. If standing water persists Routine — Biannual inspection of the hydraulic for more than 24 hours after storm performance. runoff has ceased, clogging should be further investigated and remedied. Non -routine — Performed when clogging is due Growing media Restore infiltration capacity of to the migration of sediments deep into the replacement bioretention facilities. pore spaces of the media. The frequency of replacement will depend on site -specific pollutant loading characteristics. I Perforated Subdrain ' The. perforated subdrain system storm drain outfall at the bottom of the Low Impact Development (LID) system is critical to the overall function of the system subbase. As such, special maintenance has been identified to -ensure these perforated drain systems perform as they were designed. ' Perforated subdrains leading away from the LID system is designed to provide faster release of water when accumulation occurs under the LID system. Outflow should be seen into downstream storm boxes. If not seen it is trecommended that the system is inspected using a video camera to verify no clogging has occurred. Perforated subdrains leading toward the LID system are designed to provide an opportunity for infiltration. These ' subdrains may lead to a d_rywell where additional infiltration capacity is available to reduce runoff per the stated LID goals adopted by the City. Routine Maintenance Table Required Maintenance Objective Frequency of Action Action Use a video camera to inspect the condition of the perforated drain Inspection pipes. Cleanout pipes as needed. If the Every two to five years: integrity of the pipe is compromised, then repair the damaged section(s). Where accessible, expose inlet and/or Inspection outlet of perforated pipe and watch Minimum Annually for water inflow and/or outflow. APPENDIX G STORMWATER ALTERNATIVE COMPLIANCEIVARIANCE G Stormwater Alternative ComplianceNariance Application City of Fort Collins Water Utilities Engineering Engineer Name Interwest Consulting Group Phone970-674-3300 Street Address1218 W. Ash Street, Suite A City Windsor State C0 Zip 80550 Owner Name City of Fort Collins Phone 970-221-6610 Street Address300 LaPorte Ave, Building 0 Project Name Street Facility Park Project/Application Number from Development Review (i.e. FDP123456) BDR180010 Legal description and/or address of propemf Tract A, Fast Vine Streets Facility P.U.D 927 9thStreet Fort Collins, CO Description of Project Public Park. Existing Use (check one): ❑ residential ❑ non-residential ❑ mixed -use O vacant ground Proposed Use (check one): ❑ residential ❑ non-residential ❑ mixed -use M other Public Park If non-residential or mixed use, describe in detail State the requirement from which alternative compliance/variance is sought. (Please include applicable Drainage Criteria Manual volume, chapter and section.) Providion of water quality treatment for 100% of the improvements - Volume 3, chapter 4, section 4.5.5 What hardship prevents this site from meeting the requirement? The existing conditions of the site prevent the berm surrounding the detention pond from tieing raised higher than proposed. Significantly altering the grades of the strips of proposed sidewalk: not being treated would cause damage to existing trees. The etrtpa ofproppsed eMewaa nnM be graded ro drain Os the detemWn paq Whft mehMWM the MterWad rwi w of the eWM9 today and stte Fades. What alternative is proposed for the site? Attach separate sheet if necessary water fpra9ty treatment is tmeng proNded for e9%of the r harderepe improvemerde vm a rain garden v alma. grace brdrem or mdgbv eratsr qw thy pond A Attach separate sheet if necessary 1 Stormwater Alternative ComplianceNariance Application ' City of Fort Collins Water Utilities Engineering Engineer Name 11 terwest Consulting Group Phone970-674-330D tStreet Address 1218 W. Ash Street, Suite A City Windsor _ _ State CO Zip 80550 ' Owner Name City of Fort Collins PhonA970-221-6610 Street. Address 300 LaPorte Ave, Building B 1 City Fort Collins State CO Zip 80521 Project Name Street Facility Park Project/Application Number from Development Review (i.e. FDP123456) BDR180010 Legal description and/or address of property Tract A. East.yne Streets Facility P.U.D 927 9th Street Fort Collins, CO 1 Description of Project Public Park Existing Use (check one): O residential O non-residential O mixed -use 21 vacant ground Proposed Use (check one): ❑ residential ❑ non-residential O mixed -use p other Public Park If non-residential or mixed use, describe in detail 1Section C��Alternative ComDliaiice/.Vartance��r�fbrriiafibii State the requirement from which alternative compliancetvariance is sought. (Please include 1 applicable Drainage Criteria Manual volume, chapter and section.) Tbs spOhM•Iro0 be dnipnW such eW aq VOIs 00 be w nbn Dun sls(•)brJhes In dapM a Om a dwft 0e 100-YM aWrn- VeWM Z pupW 10, SOCOM&3.9(b) 1 What hardship prevents this site from meeting the requirement? The proposed spillway length cannot be increased, as positive drainage would no longer be achieved from the crest of the spillway to the top/back of the existing curb along 9th Street. Attach separate, sheet it necessary What alternative is proposed for the site? Spillway flow depth of 0.6 feet Attach.sepWte sheet it necessary P8P $ e The owner apees'to comply with the provisions of the zoning ordinance, building code and all other applicable sections of the City Code, Land Use Code, City Plan and all other laws and ordinances affecting the construction and occupancy of the proposed building that are not directly approved by this variance. The owner understands that if this variance is approved, the structure and its occupants may be more susceptible to floodxcrunoff damage as well as other adverse drainage issues. Signature of owner: Dater -- The engineer hereby certifies that the above information, along with the reference plans and project descriptions- ---'-' ISignature of PE STAMP Date complete application submitted: tl Q ZOis Date ofapprovaUdenial:lt LA0 a' le Variance: approved O denied Staffjustification/notestconditions: Si /'-h r r rnro �' A ON► /� M4 OF AAM Approved by: Entered In Utilityrile Database. yes 0 no