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HomeMy WebLinkAboutSOUTHEAST FORT COLLINS COMMUNITY PARK - FDP - FDP160009 - REPORTS - DRAINAGE REPORTFINAL DRAINAGE REPORT Southeast Community Park 3350 Kechter Road, Fort Collins, Colorado Prepared for: CIVITAS 1200 Bannock Street Denver, CO 80204 303-571-0053 Prepared by: Interwest Consulting Group 1218 West Ash, Suite C Windsor, Colorado 80550 (970) 460-8488 March 23, 2016 Job Number 1178-109-00 TABLE OF CONTENTS TABLE OF CONTENTS .............................................................................................................. i DRAINAGE LETTER.................................................................................................................. 1 APPENDIX A VICINITY MAP AND DRAINAGE PLAN APPENDIX B HYDROLOGIC COMPUTATIONS APPENDIX C HYDRAULIC COMPUTATIONS APPENDIX D LID CALCULATIONS APPENDIX E KECHTER AND ZIEGLER AND MCCLELLANDS CREEK INFORMATION (SWMM MODEL) APPENDIX F FIRM PANEL, FLOODPLAIN INFORMATIONAND CITY OF FORT COLLINS FLOODPLAIN REVIEW CHECKLIST FOR 50% SUBMITTALS APPENDIX G SOILS INFORMATION, FIGURES AND TABLES APPENDIX H SNOUT® BMP INFORMATION 1 March 23, 2016 Ms. Heather McDowell City of Fort Collins Storm Water Utility 700 Wood Street Fort Collins, CO 80522 Re: Southeast Community Park – 3350 Kechter Road, Fort Collins, CO 80528 Final Drainage Letter Dear Heather, Please accept the following letter on behalf of the City of Fort Collins Parks Department to demonstrate the site’s compliance with the City of Fort Collins Drainage Standards. Please note that the Erosion Control and Stormwater Management Plan report has been prepared and submitted to the City as a separate document. Comments from the City of Fort Collins Stormwater Engineering department from the 2 nd PDP submittal in September of 2015 have been addressed in this letter. INTRODUCTION Southeast Community Park is a proposed community park located in the Southwest Quarter of Section 4, Township 6 North, Range 68 West of the Sixth Principal Meridian, City of Fort Collins, County of Larimer, State of Colorado. It contains approximately 50 acres and is bounded on the south by Kechter Road, the north by Saber Cat Drive and Fossil Ridge High School, the west by Ziegler Road, and the east by Lady Moon Drive. The site is bisected by McClellands Creek. Please refer to the attached vicinity map. The site is in the McClellands Basin and is included in the City’s Storm Water Management Model (SWMM) and includes basins 506, 507 and 509 and a portion of basin 510. The applicable master drainage study is the “McClellands Creek Master Plan Update”, by ICON Engineering, Inc., (November 30, 2000 and revised March 2003) and is referred to as the Master Plan. The Master Plan identifies an erosion buffer on McClellands Creek. A stream restoration project is a part of the park project and after completion of the restoration; the erosion buffer will be removed (similar to Radiant Park on the south side of Kechter). 2 EXISTING CONDITIONS The site currently has an existing ball field, BMX bike course and irrigation pond and pump house but otherwise is vacant. The north portion of the site sheet flows south to McClellands Creek and the south portion of the site sheet flows north to McClellands Creek. PROPOSED DEVELOPMENT The proposed development consists of an access road and parking lot, new concrete trail system, playground area, restrooms and shelters, multi-use turf area, interactive creek play feature and utilities for the park. The site will also include ball fields and new pedestrian bridges. McClellands Creek will be re-graded in coordination with a City Stream Stability Project. NEW PARKING OFF OF SABER CAT AND LADY MOON Several new parking spaces have been proposed along Saber Cat Drive and Lady Moon Drive. Both areas will drain toward the flowline of the drives and will follow existing conditions. The parking spaces in Saber Cat Drive will drain to the north flowline of Saber Cat Drive where an existing inlet located to the east will collect the flow. The parking spaces in Lady Moon Drive will drain to the flowline of Lady Moon Drive where an existing inlet located to the south will collect the flow. Both of these inlets drain to the existing irrigation pond. The existing irrigation pond has no outlet so detention and water quality naturally occurs for all drainage directed to the pond. The pond acts as a sediment basin and detention was designed to limit flows over the spillway. The irrigation pond is a joint facility between the Poudre School District (PSD) and the City of Fort Collins Parks department. With the addition of new runoff directed toward this pond from the on street parking areas described above and the new BMX track, additional maintenance of the pond may need to occur. The City Park’s department will coordinate with PSD on the maintenance of the pond. BASIN DESCRIPTIONS The site is divided into six basins, A-F. The basins are delineated on the Drainage plan which is attached to this report. Basin A is adjacent to Basin F and is in the western portion of the site, south of McClellands Creek. It includes a parking lot, drive aisle off of Ziegler Road and open field area. The drive aisle and parking areas sheet flow north over porous pavers. The southern portion of the basin sheets north to the same porous pavers. Minor flows will be collected by the porous paver underdrain system and conveyed to a storm system that directs the water east. Major flows will spill over the curb and gutter and flow north directly to McClellands Creek. The time of concentration for this basin is 12.1 minutes. 3 Basin B is located just north of Basin A and south of McClellands Creek. It includes a concrete trail system and sidewalks, landscape areas, community gardens, restroom, picnic shelter and playground. The sod, sidewalk areas and playground in the east of this basin drain north to a water quality trench system (French drain) and then to McClellands Creek after treatment. The natural areas and community gardens of the basin drain north through a grass buffer zone and then to McClellands Creek. Minor flows will be cutoff by the French drain and major flows will sheet over the French drain directly into McClellands Creek. The time of concentration for this basin is 14.2 minutes. Basin C is comprised of the portion of the site adjacent to Basins A and B on the east and south of McClellands Creek. It includes a concrete trail system and all-purpose fields. This basin drains to the northeast to a water quality trench system (French drain) and then to McClellands Creek after treatment. Minor flows will be cutoff by the French drain and major flows will sheet over the French drain directly into McClellands Creek. The time of concentration for this basin is 15.3 minutes. Basin D is comprised of the north portion of the site north of McClellands Creek up to the proposed baseball fields and south of Saber Cat Drive. It includes sidewalks, dog park and landscape areas. The western half of the basin – which only impervious area is the sidewalk system – sheet flows through a native grasses buffer zone and then into McClellands Creek. The sidewalk/hardscape areas and dog park in the easter half of the basin sheet flows south to a water quality trench system (French drain) and then to McClellands Creek after treatment. Minor flows will be cutoff by the French drain and major flows will sheet over the French drain directly into McClellands Creek. The dog park French drain system has its own outfall into the creek. The time of concentration for this basin is 13.9 minutes. Basin E is comprised of the northeast portion of the site north of McClellands Creek. It includes the BMX facility. This basin drains to a SNOUT® water quality facility with sump located within the track. This then discharges to the existing storm system in Lady Moon Drive that then discharges to the existing irrigation pond where 100% water quality treatment will occur. As previously mentioned, there is no below surface outfall for the irrigation pond so it acts as a sediment basin. The time of concentration for this basin is 13.1 minutes. Basin F is comprised of the drainage ditch adjacent to Ziegler Road in the southwestern most portion of the site. This basin drains to the north to McClellands Creek via a ditch and culvert located under the access drive. The time of concentration for this basin is 12.2 minutes. Basin G is comprised of the restroom building, two baseball fields, sidewalk/hardscape between the fields, and a portion of the sidewalk adjacent to the baseball fields. This basin drains to the south to a water quality trench system (French drain) and then to McClellands creek after treatment. Minor flows will be cutoff by the French drain and major flows will sheet over the French drain directly to McClellands Creek. The French drain system for this basin connects to a manhole and has a single outfall to the creek through an 18” pipe. The time of concentration for this basin is 14.7 minutes. According to the SWMM model, the peak flow of McClellands Creek in this area is at a time of 1 hour and 15 to 17 minutes. Please refer to the Appendix E for reference to the model. Because the basins’ time of concentrations are much shorter than the time to peak flow of McClellands 4 Creek and the increase in percent imperviousness due to the park’s development has not changed the flow of McClellands Creek, it has been deemed acceptable by the City that detention will not be provided for this site. More discussion is included in the following section under Proposed Model. OFFSITE DRAINAGE Offsite drainage is introduced to the site from the three 30-inch culverts crossing the roundabout from south to north at Kechter and Ziegler. This water will continue to follow current conditions and will flow north and pass through two proposed 30-inch culverts at the park’s entrance drive. Because upstream basins have been diverted, the McClellands Basin SWMM model was updated. Three models will be used for this report and will be run on the Environmental Protection Agency (EPA) - Storm Water Management Model - Version PC.1. Duplicate Effective Model The duplicate effective model is the current model from the City. No changes were made in any modeling parameters and the model was run on a computer at Interwest Consulting Group. Portions of the input and output from this model are in Appendix E. The duplicate effective model output matches the City model output. The filename is MMCEX.DAT. The duplicate effective SWMM model determined that 299 cfs drained to the roundabout at Kechter and Ziegler (overtopping and in the pipes). Corrected Effective Model A corrected effective model was developed by taking the duplicated effective model and rerouting Basin 513, which contains Mail Creek Crossing and Kechter Crossing subdivisions, to node 313 since these subdivisions now bypass the original model’s conveyance to the roundabout at Kechter and Ziegler. Also, Basin 511 (Homestead PUD) was rerouted to new pond 399 and then released to the conveyance element that drains to the roundabout. The filename is MMCEXCE.DAT. The existing conditions SWMM model determined that 299 cfs drained to the roundabout (overtopping and in the pipes). The updated model (corrected effective) determined that 165.8 cfs now drains to the roundabout removing 133.2 cfs from the system. The two proposed 30-inch culverts at the park’s entrance drive will convey 114 cfs during the 100-year event. The remaining runoff (approximately 52 cfs) will overtop the drive aisle and be conveyed to the creek without impacting any structures. Proposed Model The proposed model has been developed by taking the corrected effective model and increasing the percent impervious values of basin 506, 507, 509, and 510 from 5% to 8.6% to reflect the Southeast Community Park Development. This was done to show that the increase in percent imperviousness does not impact McClellands Creek at nodes 411 and 412. The filename is MMCEXPROP.DAT. The peak flow of the corrected effective model at nodes 411 and 412 is 1,199.2 cfs and 1,227.6 cfs, respectively. The peak flow of the proposed model at nodes 411 and 412 is 1,198.9 cfs and 1,227.0 cfs, respectively. The increase in percent imperviousness does not adversely affect McClellands Creek. 5 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 peaks, volumes, and pollutant loads from urbanizing areas, stabilizing drainageways and implementing long-term source controls. The Four Step Process applies to the management of smaller, frequently occurring events. Step 1: Employ Runoff Reduction Practices To reduce runoff peaks, volumes, and pollutant loads from urbanizing areas, implement Low Impact Development (LID) strategies, including Minimizing Directly Connected Impervious Areas (MDCIA). Runoff for the site will be routed through porous pavers, vegetated/ grassy buffer areas and water quality trench system systems thereby reducing runoff from impervious surfaces over permeable areas to slow runoff and increase the time of concentration and promote infiltration. Step 2: Implement BMPs that Provide a Water Quality Capture Volume with Slow Release Once runoff has been minimized, a portion of the remaining runoff shall be treated through the water quality trench systems where sediment will settle and cleaner water will release through the underdrain system. The porous pavers help reduce total runoff by allowing the water to infiltrate. The irrigation pond allows sediments to settle while incorporating zero release. 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. Rip rap will be used as a level spreader at the outlet of pipes that discharge into the McClellands Creek. The existing outfall into McClellands Creek from the drainage swale adjacent to Ziegler will be maintained in order to prevent erosion and maintain channel stability. Step 4: Implement Site Specific and Other Source Control BMPs Proactively controlling pollutants at their source by preventing pollution rather than removing contaminants once they have entered the stormwater system or receiving waters is important when protecting storm systems and receiving waters. This can be accomplished through site specific needs such as construction site runoff control, post-construction runoff control and pollution prevention / good housekeeping. It will be the responsibility of the contractor to develop a procedural best management practice for the site. WATER QUALITY As the drainage leaves the site, water quality will be achieved through a network of best management practices (BMPs) including porous pavers, grass buffers, water quality trench systems (French drains), and SNOUT® water quality facility with sump and storm system. It should be noted that this overall site is only going to be 10% impervious and most runoff from minor storms will infiltrate and not reach the water quality BMPs. The porous pavers along the drive aisle and parking will treat that area before being released to McClellands Creek. These porous pavers will reduce volume, provide treatment and slow release of the water quality capture volume. 6 The grass buffer between the concrete trail areas and McClellands Creek will treat most of the concrete trail. Water will sheet from the concrete trail to the grass buffer where filtration of sediment will occur before the water reaches McClellands Creek. The water quality trench systems (French drains), located in basins B, C, D and G will treat the impervious portions of these basins as well as fertilized turf areas. The trench will be constructed with a layer of filter material and will convey flow in a slow and shallow manner were filtration of sediment will occur. Flow will be directed to storm systems or underdrains where it will then flow to McClellands Creek. A scour stop system or rip rap will be used as a level spreader at the outlet of these pipes. Because the park is adding very little hardscape, there is effectively no runoff from the typical “water quality event” of 0.5 inches. The water quality trenches are an extra way of treating the very minor flows that are expected. The BMX area in basin E will have a SNOUT® water quality facility with sump. This system will drain to the existing irrigation pond where further sediment will fall out below the pond outlet. This irrigation pond provides 100% treatment and is jointly owned by the School District and the City. Please refer to Appendix H for SNOUT® information and details. DEVELOPMENT CRITERIA REFERENCE AND CONSTRAINTS Runoff reduction practices (LID techniques) are also required. No less than fifty percent of any newly added impervious area must be treated using one or a combination of LID techniques. The project added 201,800 sf of new impervious area. Using the porous pavers and the water quality trench systems as LID techniques, 101,600 sf of new impervious area (50%) will be treated using these two LID techniques which satisfies the 50% requirement. Additionally, approximately 772,500 sf of runoff area will be intercepted and treated by the water quality trench system which is 40% of the site. A small portion of this area is impervious (43,570 sf) as the majority of the area is highly maintained turf area (soccer field, baseball fields). It is anticipated that these turf areas will produce “dirty” runoff from fertilizers which the water quality trench systems will capture and infiltrate prior to reaching the creek. All other new impervious areas that are not intercepted by the porous pavers or water quality trench system will treated as the water passes through the grassy buffer areas. However, these areas were not included in the LID calculation. No less than twenty five percent of any newly added pavement areas must be treated using a permeable pavement technology. The project adds 58,576 sf of new pavement area. This area includes the drive aisle and parking area on-site and the additional parking area on Saber Cat Drive. The pavement added for the turn lanes on Ziegler and the additional parking area on Lady Moon Drive are not included as these areas are within ROW. This project will incorporate 16,500 sf of porous pavers which is 28% of the newly added pavement and satisfies the code. The pavers in the parking lot have a pavement area run on ratio of 2.5:1 which does not exceed the recommended maximum run on ratio of 3:1. The run on ratio is increased if you consider the pervious area tributary to the pavers which is the grass field just south of the parking lot. However, the runoff from this grass area is minimal during the 2-yr event and isn’t anticipated to negatively impact the treatment level that the porous pavers will provide. 7 FLOODPLAIN This development is subject to Chapter 10 of the City Code. A floodplain use permit will be required for each site construction element in the floodplain and will be submitted with final compliance documents. A Floodplain modeling report was completed for the McClellands Creek with a separate submittal and will be coordinated with The City of Fort Collins Stormwater department. Modeling is required in this area because the McClellands Creek will be re-graded and re-aligned in coordination with a City Stream Stability Project. The McClellands Creek floodplain/floodway in this area is currently only a City of Fort Collins regulated floodplain/floodway, and is not a Federal Emergency Management Agency (FEMA) regulated floodplain. Please refer to Appendix F for a copy of the FEMA FIRM Panel #08069C0994F dated December 19, 2006 and the City of Fort Collins Floodplain Review Checklist for 50% Development Review Submittals. CONCLUSION The design minimizes impacts to other utilities and properties and maintains the existing drainage flow paths as much as possible. The design will effectively control damage from storm runoff originating from the site. The recommended BMPs are sufficient to reduce runoff peaks, volumes and pollutant loads from the relatively minimal impervious areas of the site. We appreciate your time and consideration in reviewing this submittal. Please call if you have any questions (970) 460-8485. Sincerely, Reviewed by, Skylar Brower, P.E. Michael Oberlander, P.E., LEED AP Colorado Professional Engineer 44248 Colorado Professional Engineer 34288 Interwest Consulting Group Interwest Consulting Group Attachments A APPENDIX A VICINITY MAP AND DRAINAGE PLAN PROPOSED MINOR CONTOUR PROPOSED MAJOR CONTOUR EXISTING MINOR CONTOUR EXISTING MAJOR CONTOUR PROPOSED DRAINAGE BASIN MAJOR STORM RUNOFF COEFFICIENT DRAINAGE BASIN AREA, ACRES DRAINAGE BASIN ID LEGEND PROPOSED DIRECTION OF OVERLAND FLOW DESIGN POINT EXISTING FLOODPLAIN PROPOSED FLOODPLAIN EROSION BUFFER PROPOSED STORM PIPE Š 0 SCALE: 1" = 80' 80 40 80 160 DRAINAGE PLAN DRN-1 31 of 61 Stamp: Checked: Drawn: CVT Proj. #: SOUTHEAST COMMUNITY PARK 05.12.2015 Project Development Plan Issue Record: Revisions: Consultants: Landscape Architect 3350 Kechter Road, Fort Collins CO, 80528 1200 Bannock St. Denver, CO 80204 Tel. 303 571.0053 Fax 303 425.0438 Ripley Design Inc. (970) 224-5828 970-484-0117 RB+B Architects, Inc. Architect Civil Engineer Interwest Design Group (970) 674-3300 215 North Mason Street Fort Collins, Colorado 80521 tel: 970.221.6360 www.fcgov.com/parkplanning/ 2-13-0010 Mechanical Engineer Abrahamson Engineering, Inc. 970-221-2569 Lighting Design Clanton & Associates 303-530-7229 Irrigation Design Hines Inc 970-282-1800 Drawing Name: B APPENDIX B HYDROLOGIC COMPUTATIONS Interwest Consulting Group RUNOFF COEFFICIENTS & % IMPERVIOUS LOCATION: SE Community Park PROJECT NO: 1179-109-00 COMPUTATIONS BY: es DATE: 2/18/2016 Recommended Runoff Coefficients from Table RO-11 of Fort Collins Stormwater Criteria Manual Recommended % Impervious from Urban Storm Drainage Criteria Manual (Type C Soils) Table RO-3 Runoff % coefficient Impervious C Streets, parking lots (asphalt): 0.95 100 Sidewalks (concrete): 0.95 96 Roofs: 0.95 90 Gravel Areas: 0.50 40 Porous Pavers: 0.40 22 Landscape Areas: 0.25 0 SUBBASIN TOTAL TOTAL ROOF PAVED SIDEWALK GRAVEL POROUS LANDSCAPE RUNOFF % DESIGNATION AREA AREA AREA AREA AREA AREA PAVEMENT AREA COEFF. Impervious (ac.) (sq.ft) (sq.ft) (sq.ft) (sq.ft) (sq. ft) (sq. ft) (sq.ft) (C) A7.0 305,991 0 31,013 7,294 5,812 16,499 245,372 0.35 14 B6.0 262,391 5,478 0 22,650 36,625 0 197,638 0.36 16 C 10.4 455,144 0 0 26,678 5,776 0 422,691 0.29 6 D 11.5 500,403 0 0 28,879 15,178 0 456,346 0.30 7 E1.3 56,251 0 0 0 0 0 56,251 0.25 0 F1.1 46,435 0 1,891 1,918 0 0 42,626 0.31 8 G7.6 331,526 1,372 0 37,731 0 0 292,423 0.33 11 Total 37.34 1626615 6850 32904 125150 63390 16499 1713347 0.38 11 Equations 164905 - Calculated C coefficients & % Impervious are area weighted C =  (Ci Ai) / At Ci = runoff coefficient for specific area, Ai Ai = areas of surface with runoff coefficient of Ci n = number of different surfaces to consider At = total area over which C is applicable; the sum of all Ai's 02-18-16 Flow.xls STANDARD FORM SF-2 TIME OF CONCENTRATION - 2 YR LOCATION: SE Community Park PROJECT NO: 1179-109-00 COMPUTATIONS BY: es DATE: 2/18/2016 2-yr storm Cf = 1.00 SUB-BASIN INITIAL /OVERLAND TRAVEL TIME / GUTTER OR CHANNEL FLOW tc CHECK FINAL REMARKS DATA TIME (ti) (tt) (URBANIZED BASIN) tc DESIGN SUBBASIN(s) Area C Length Slope ti Length Slope n Vel. tt tc = Total L tc=(l/180)+10 PONIT (ac) (ft) (%) (min) (ft) (%) Manning (ft/s) (min) ti + tt (ft) (min) (min) (1) (2) (3) (4) (5) (6) (7) (8) rough. (9) (10) (11) (12) (13) (14) A A 7.02 0.35 20 2.0 5.0 800 0.8 0.016 1.7 7.66 12.6 820 14.6 12.6 B B 6.02 0.36 300 2.0 19.0 450 2.2 0.030 1.6 4.72 23.7 750 14.2 14.2 C C 10.45 0.29 300 2.0 20.7 650 1.1 0.030 1.1 9.64 30.4 950 15.3 15.3 D D 11.49 0.30 300 2.0 20.6 400 1.1 0.030 1.1 5.93 26.6 700 13.9 13.9 E E 1.29 0.25 300 2.0 21.9 250 2.0 0.030 1.5 2.75 24.6 550 13.1 13.1 F F 1.07 0.31 20 2.0 5.3 650 1.9 0.030 1.5 7.43 12.7 670 13.7 12.7 G G 7.61 0.33 300 1.0 24.9 551 0.5 0.013 1.7 5.25 30.1 851 14.7 14.7 EQUATIONS: tc = ti + tt ti = [1.87 (1.1 - CCf ) L0.5 ] / S 1/3 tt = L/Vel. Velocity from Manning's Equation with R=0.1 (corresponds to Figure 3-3 of City of Fort Collins Design Manual) final tc = minimum of ti + tt and urbanized basin check min. tc = 5 min. due to limits of IDF curves 02-18-16 Flow.xls STANDARD FORM SF-2 TIME OF CONCENTRATION - 10 YR LOCATION: SE Community Park PROJECT NO: 1179-109-00 COMPUTATIONS BY: es DATE: 2/18/2016 10-yr storm Cf = 1.00 SUB-BASIN INITIAL /OVERLAND TRAVEL TIME / GUTTER OR CHANNEL FLOW tc CHECK FINAL REMARKS DATA TIME (ti) (tt) (URBANIZED BASIN) tc DESIGN SUBBASIN(s) Area C Length Slope ti Length Slope n Vel. tt tc = Total L tc=(l/180)+10 PONIT (ac) (ft) (%) (min) (ft) (%) Manning (ft/s) (min) ti + tt (ft) (min) (min) (1) (2) (3) (4) (5) (6) (7) (8) rough. (9) (10) (11) (12) (13) (14) A A 7.02 0.35 20 2.0 5.0 800 0.8 0.016 1.7 7.66 12.6 820 14.6 12.6 B B 6.02 0.36 300 2.0 19.0 450 2.2 0.030 1.6 4.72 23.7 750 14.2 14.2 C C 10.45 0.29 300 2.0 20.7 650 1.1 0.030 1.1 9.64 30.4 950 15.3 15.3 D D 11.49 0.30 300 2.0 20.6 400 1.1 0.030 1.1 5.93 26.6 700 13.9 13.9 E E 1.29 0.25 300 2.0 21.9 250 2.0 0.030 1.5 2.75 24.6 550 13.1 13.1 F F 1.07 0.31 20 2.0 5.3 650 1.9 0.030 1.5 7.43 12.7 670 13.7 12.7 G G 7.61 0.33 300 1.0 24.9 551 0.5 0.013 1.7 5.25 30.1 851 14.7 14.7 EQUATIONS: tc = ti + tt ti = [1.87 (1.1 - CCf ) L0.5 ] / S 1/3 tt = L/Vel. Velocity from Manning's Equation with R=0.1 (corresponds to Figure 3-3 of City of Fort Collins Design Manual) final tc = minimum of ti + tt and urbanized basin check min. tc = 5 min. due to limits of IDF curves 02-18-16 Flow.xls STANDARD FORM SF-2 TIME OF CONCENTRATION - 100 YR LOCATION: SE Community Park PROJECT NO: 1179-109-00 COMPUTATIONS BY: es DATE: 2/18/2016 100-yr storm Cf = 1.25 SUB-BASIN INITIAL /OVERLAND TRAVEL TIME / GUTTER OR CHANNEL FLOW tc CHECK FINAL REMARKS DATA TIME (ti) (tt) (URBANIZED BASIN) tc DESIGN SUBBASIN(s) Area C C*Cf Length Slope ti Length Slope n Vel. tt tc = Total L tc=(l/180)+10 PONIT (ac) (ft) (%) (min) (ft) (%) Manning (ft/s) (min) ti + tt (ft) (min) (min) (1) (2) (3) (4) (5) (6) (7) (8) rough. (9) (10) (11) (12) (13) (14) A A 7.02 0.35 0.44 20 2.0 4.4 800 0.8 0.016 1.7 7.66 12.1 820 14.6 12.1 B B 6.02 0.36 0.45 300 2.0 16.7 450 2.2 0.030 1.6 4.72 21.4 750 14.2 14.2 C C 10.45 0.29 0.37 300 2.0 18.8 650 1.1 0.030 1.1 9.64 28.5 950 15.3 15.3 D D 11.49 0.30 0.37 300 2.0 18.7 400 1.1 0.030 1.1 5.93 24.6 700 13.9 13.9 E E 1.29 0.25 0.31 300 2.0 20.2 250 2.0 0.030 1.5 2.75 23.0 550 13.1 13.1 F F 1.07 0.31 0.38 20 2.0 4.8 650 1.9 0.030 1.5 7.43 12.2 670 13.7 12.2 G G 7.61 0.33 0.42 300 1.0 22.2 551 0.5 0.013 1.7 5.25 27.4 851 14.7 14.7 EQUATIONS: tc = ti + tt ti = [1.87 (1.1 - CCf ) L 0.5 ] / S 1/3 tt = L/Vel. Velocity from Manning's Equation with R=0.1 (corresponds to Figure 3-3 of City of Fort Collins Design Manual) final tc = minimum of ti + tt and urbanized basin check min. tc = 5 min. due to limits of IDF curves 02-18-16 Flow.xls RATIONAL METHOD PEAK RUNOFF (City of Fort Collins, 2-Yr Storm) LOCATION: SE Community Park PROJECT NO: 1179-109-00 COMPUTATIONS BY: es DATE: 2/18/2016 2 yr storm, Cf = 1.00 DIRECT RUNOFF CARRY OVER TOTAL REMARKS Design Tributary A C Cf tc i Q (2) from Q (2) Q(2)tot Sub-basin Design Point (ac) (min) (in/hr) (cfs) Point (cfs) (cfs) A A 7.02 0.35 12.6 2.02 5.0 5.0 B B 6.02 0.36 14.2 1.91 4.2 4.2 C C 10.45 0.29 15.3 1.85 5.7 5.7 D D 11.49 0.30 13.9 1.93 6.6 6.6 E E 1.29 0.25 13.1 1.99 0.6 0.6 F F 1.07 0.31 12.7 2.01 0.7 0.7 G G 7.61 0.33 14.7 1.88 4.8 4.8 Q = Cf C iA Q = peak discharge (cfs) C = runoff coefficient Cf = frequency adjustment factor i = rainfall intensity (in/hr) from City of Fort Collins IDF curve (4/16/99) A = drainage area (acres) i = 24.221 / (10+ tc)0.7968 02-18-16 Flow.xls RATIONAL METHOD PEAK RUNOFF (City of Fort Collins, 10-Yr Storm) LOCATION: SE Community Park PROJECT NO: 1179-109-00 COMPUTATIONS BY: es DATE: 2/18/2016 10 yr storm, Cf = 1.00 DIRECT RUNOFF CARRY OVER TOTAL REMARKS Design Tributary A C Cf tc i Q (10) from Q (10) Q(10)tot Sub-basin Design Point (ac) (min) (in/hr) (cfs) Point (cfs) (cfs) A A 7.02 0.35 12.6 3.44 8.5 8.5 B B 6.02 0.36 14.2 3.27 7.1 7.1 C C 10.45 0.29 15.3 3.15 9.7 9.7 D D 11.49 0.30 13.9 3.30 11.3 11.3 E E 1.29 0.25 13.1 3.39 1.1 1.1 F F 1.07 0.31 12.7 3.44 1.1 1.1 G G 7.61 0.33 14.7 3.21 8.1 8.1 Q = Cf C iA Q = peak discharge (cfs) C = runoff coefficient Cf = frequency adjustment factor i = rainfall intensity (in/hr) from City of Fort Collins IDF curve (4/16/99) A = drainage area (acres) i = 41.44 / (10+ tc)0.7974 02-18-16 Flow.xls RATIONAL METHOD PEAK RUNOFF (City of Fort Collins, 100-Yr Storm) LOCATION: SE Community Park PROJECT NO: 1179-109-00 COMPUTATIONS BY: es DATE: 2/18/2016 100 yr storm, Cf = 1.25 DIRECT RUNOFF CARRY OVER TOTAL REMARKS Des. Area A C Cf tc i Q (100) from Q (100) Q(100)tot Design Point Design. (ac) (min) (in/hr) (cfs) Point (cfs) (cfs) A A 7.02 0.44 12.1 7.18 22.1 22.1 B B 6.02 0.45 14.2 6.68 18.1 18.1 C C 10.45 0.37 15.3 6.44 24.8 24.8 D D 11.49 0.37 13.9 6.74 28.8 28.8 E E 1.29 0.31 13.1 6.93 2.8 2.8 F F 1.07 0.38 12.2 7.15 2.9 2.9 G G 7.61 0.42 14.7 6.56 20.7 20.7 Q = C iA Q = peak discharge (cfs) C = runoff coefficient i = rainfall intensity (in/hr) from City of Fort Collins IDF curve (4/16/99) A = drainage area (acres) i = 84.682 / (10+ tc)0.7975 02-18-16 Flow.xls SUMMARY DRAINAGE SUMMARY TABLE Design Tributary Area C (2) C (10) C (100) tc (2) tc (10) tc (100) Q(2)tot Q(10)tot Q(100)tot Sub-basin Point (ac) (min) (min) (min) (cfs) (cfs) (cfs) A A 7.0 0.35 0.35 0.44 12.6 12.6 12.1 5.0 8.5 22.1 B B 6.0 0.36 0.36 0.45 14.2 14.2 14.2 4.2 7.1 18.1 C C 10.4 0.29 0.29 0.37 15.3 15.3 15.3 5.7 9.7 24.8 D D 11.5 0.30 0.30 0.37 13.9 13.9 13.9 6.6 11.3 28.8 E E 1.3 0.25 0.25 0.31 13.1 13.1 13.1 0.6 1.1 2.8 F F 1.1 0.31 0.31 0.38 12.7 12.7 12.2 0.7 1.1 2.9 G G 7.6 0.33 0.33 0.42 14.7 14.7 14.7 4.8 8.1 20.7 Page 1 C APPENDIX C HYDRAULIC CALCULATIONS Interwest Consulting Group 1218 W. Ash, Suite C Windsor, CO 80550 Inlet Flow Calculation for Area Inlets Project: Southeast Community Park Job Number : 1178-109-00 Calculations by : ta Date : 3/18/2016 Objective: to find the number of grates required for Type C area inlets in grassy areas Geometry at inlet : Close Mesh Grate Width (W): 2.625 feet Length (L): 3.3542 feet Open Area (A): 6.6944 sq ft Reduction Factor (F): 50% Grate Flow: Use the orifice equation Qi = C*A*SQRT(2*g*H) to find the ideal inlet capacity.* *See Hydraulic Design Handbook by McGraw-Hill for verificaiton of equation use and C value C = Orifice discharge coefficient= 0.67 A = Orifice area (ft2) - open area of grate g = gravitational constant = 32.2 ft/s2 H = head on grate centroid, ponding depth (feet) Then multiply by the reduction factor for the allowable capacity. QG = Qi * (1-F) DP A Q10 = 8.5 cfs Q100 = 22.1 cfs H = 0.5 ft Single Type C Inlet Double Type C Inlet Triple Type CInlet A = 1*A A = 2*A A = 3*A =6.69ft2 = 13.39 ft2 = 38.00 ft2 Qi = C*A*SQRT(2*g*H) Qi = C*A*SQRT(2*g*H) Qi = C*A*SQRT(2*g*H) = 25.45 cfs = 50.90 cfs = 144.47 cfs QG = Qi * F QG = Qi * F QG = Qi * F = 12.73 cfs = 25.45 cfs = 72.24 cfs USE : Single Type C Inlet Grate Dimensions and information: WSEL Page1 Culvert Calculator Report SECP Twin 30" Culverts x:\...\culvertmaster\2-30in culverts (update).cvm 03/23/16 10:27:52 AM Interwest Consulting Group © Haestad Methods, Inc. 37 Brookside Road Waterbury, CT 06708 USA +1-203-755-1666 Project Engineer: Interwest Consulting Group CulvertMaster v3.0 [3.0003] Page 1 Solve For: Discharge Culvert Summary Allowable HW Elevation 4,911.50 ft Headwater Depth/Height 2.52 Computed Headwater Elevation 4,911.50 ft Discharge 114.07 cfs Inlet Control HW Elev. 4,911.20 ft Tailwater Elevation 4,906.80 ft Outlet Control HW Elev. 4,911.50 ft Control Type Outlet Control Grades Upstream Invert 4,905.20 ft Downstream Invert 4,904.35 ft Length 112.00 ft Constructed Slope 0.007589 ft/ft Hydraulic Profile Profile CompositeM2PressureProfile Depth, Downstream 2.45 ft Slope Type Mild Normal Depth N/A ft Flow Regime Subcritical Critical Depth 2.37 ft Velocity Downstream 11.67 ft/s Critical Slope 0.016741 ft/ft Section Section Shape Circular Mannings Coefficient 0.013 Section Material Concrete Span 2.50 ft Section Size 30 inch Rise 2.50 ft Number Sections 2 Outlet Control Properties Outlet Control HW Elev. 4,911.50 ft Upstream Velocity Head 2.10 ft Ke 0.20 Entrance Loss 0.42 ft Inlet Control Properties Inlet Control HW Elev. 4,911.20 ft Flow Control N/A Inlet Type Groove end projecting Area Full 9.8 ft² K 0.00450 HDS 5 Chart 1 M 2.00000 HDS 5 Scale 3 C 0.03170 Equation Form 1 Y 0.69000 Project Description Flow Element: Irregular Section Friction Method: Manning Formula Solve For: Normal Depth Input Data Channel Slope: 0.02000 ft/ft Discharge: 52.00 ft³/s Options Current Roughness Weighted Metho ImprovedLotters Open Channel Weighted Roughness ImprovedLotters Closed Channel Weighted Roughne Hortons Results Roughness Coefficient: 0.013 Water Surface Elevation: 11.40 ft Elevation Range: 11.00 to 12.15 ft Flow Area: 9.01 ft² Wetted Perimeter: 42.24 ft Top Width: 42.23 ft Normal Depth: 0.40 ft Critical Depth: 0.55 ft Critical Slope: 0.00358 ft/ft Velocity: 5.77 ft/s Velocity Head: 0.52 ft Specific Energy: 0.92 ft Froude Number: 2.20 Flow Type: Supercritical Segment Roughness Section Geometry Start Station End Station Roughness Coefficient (-0+38, 12.15) (0+35, 12.00) 0.013 Station Elevation -0+38 12.15 -0+20 11.35 Worksheet for SECP Entry Drive Spill Worksheet for SECP Entry Drive Spill Station Elevation 0+00 11.00 0+20 11.35 0+35 12.00 Project Description Flow Element: Irregular Section Friction Method: Manning Formula Solve For: Normal Depth Section Data Roughness Coefficient: 0.013 Channel Slope: 0.02000 ft/ft Normal Depth: 0.40 ft Elevation Range: 11.00 to 12.15 ft Discharge: 52.00 ft³/s SECP Entry Drive Cross Section for SECP Entry Drive Spill Project Description Flow Element: Trapezoidal Channel Friction Method: Manning Formula Solve For: Normal Depth Input Data Roughness Coefficient: 0.030 Channel Slope: 0.01000 ft/ft Left Side Slope: 4.00 ft/ft (H:V) Right Side Slope: 4.00 ft/ft (H:V) Bottom Width: 4.00 ft Discharge: 166.00 ft³/s Results Normal Depth: 2.21 ft Flow Area: 28.46 ft² Wetted Perimeter: 22.25 ft Top Width: 21.71 ft Critical Depth: 2.10 ft Critical Slope: 0.01257 ft/ft Velocity: 5.83 ft/s Velocity Head: 0.53 ft Specific Energy: 2.74 ft Froude Number: 0.90 Flow Type: Subcritical GVF Input Data Downstream Depth: 0.00 ft Length: 0.00 ft Number Of Steps: 0 GVF Output Data Upstream Depth: 0.00 ft Profile Description: N/A Headloss: 0.00 ft Downstream Velocity: 0.00 ft/s Upstream Velocity: 0.00 ft/s Normal Depth: 2.21 ft Critical Depth: 2.10 ft Channel Slope: 0.01000 ft/ft Worksheet for SECP West Channel Worksheet for SECP West Channel Critical Slope: 0.01257 ft/ft Project Description Flow Element: Trapezoidal Channel Friction Method: Manning Formula Solve For: Normal Depth Section Data Roughness Coefficient: 0.030 Channel Slope: 0.01000 ft/ft Normal Depth: 2.21 ft Left Side Slope: 4.00 ft/ft (H:V) Right Side Slope: 4.00 ft/ft (H:V) Bottom Width: 4.00 ft Discharge: 166.00 ft³/s SECP West Channel Cross Section for SECP West Channel D APPENDIX D LID CALCULATIONS Š 0 SCALE: 1" = 80' 80 40 80 160 LID EXHIBIT Stamp: Checked: Drawn: CVT Proj. #: SOUTHEAST COMMUNITY PARK 05.12.2015 Project Development Plan Issue Record: Revisions: Consultants: Landscape Architect 3350 Kechter Road, Fort Collins CO, 80528 1200 Bannock St. Denver, CO 80204 Tel. 303 571.0053 Fax 303 425.0438 Ripley Design Inc. (970) 224-5828 970-484-0117 RB+B Architects, Inc. Architect Civil Engineer Interwest Design Group (970) 674-3300 215 North Mason Street Fort Collins, Colorado 80521 tel: 970.221.6360 www.fcgov.com/parkplanning/ 2-13-0010 Mechanical Engineer Abrahamson Engineering, Inc. 970-221-2569 Lighting Design Clanton & Associates 303-530-7229 Irrigation Design Hines Inc 970-282-1800 95% CONSTRUCTION DOCUMENTS Drawing Name: 09.02.2015 Project Development Plan 12.04.2015 90% Construction Documents 02.09.2016 95% Construction Documents 03.23.2016 Final Development Plan LEGEND E APPENDIX E KECHTER AND ZIEGLER CROSSING INFORMATION AND MCCLELLANDS CREEK INFORMATION (SWMM MODEL) I APPENDIX F FIRM PANEL, FLOODPLAIN INFORMATION AND CITY OF FORT COLLINS FLOODPLAIN REVIEW CHECKLIST FOR FINAL SUBMITTALS X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X EXISTING MINOR CONTOUR EXISTING MAJOR CONTOUR LEGEND EXISTING MINOR CONTOUR EXISTING MAJOR CONTOUR PROPOSED MINOR CONTOUR PROPOSED MAJOR CONTOUR EFFECTIVE CITY FLOODWAY/FLOODPLAIN PROPOSED CITY FLOODWAY/FLOODPLAIN EFFECTIVE BFE AND ELEVATION CROSS-SECTION AND NUMBER PROPOSED BFE AND ELEVATION ADDED OR UPDATED CROSS-SECTION AND NUMBER PROPOSED CREEK ALIGNMENT STATIONING EXISTING CREEK ALIGNMENT STATIONING 0 SCALE: 1" = 80' 80 40 80 160 FLOODPLAIN PLAN J APPENDIX G SOILS INFORMATION, FIGURES, TABLES AND EXCERPTS FROM REPORTS K APPENDIX H SNOUT® WATER QUALITY / BMP INFORMATION Quick-Start Application Guide with SNOUT® to Structure Ratio (STSR) Methodology Background: The SNOUT system from Best Management Products, Inc. (BMP, Inc.) is based on a vented hood that can reduce floatable trash and debris, free oils, and other solids from stormwater discharges. In its most basic application, a SNOUT hood is installed over the outlet pipe of a catch basin or other stormwater quality structure which incorporates a deep sump (see Installation Drawing). The SNOUT forms a baffle in the structure which collects floatable debris and free oils on the surface of the captured stormwater, while permitting heavier solids to sink to the bottom of the sump. The clarified intermediate layer is forced out of the structure through the open bottom of the SNOUT by displacement from incoming flow. The resultant discharge contains considerably less unsightly trash and other gross pollutants, and can also offer reductions of free-oils and finer solids. What follows are basic design tips to optimize the performance of SNOUT systems. Design Recommendations for Site:  Establish SNOUT to Structure Ratio (STSR) for site as follows: Heavy Traffic and Pollutant Loading Applications (STSR 1:1): This includes gas stations, convenience stores, fast food restaurants, vehicle repair facilities, stores with “drive through” service (e.g. banks, drug stores, dry cleaners, coffee shops), loading docks, distribution facilities, marinas, hospitals, transportation terminals (air, bus, train, sea, shipping), school bus loading areas, maintenance facilities, light industrial sites, waste disposal facilities or “dumpster areas”, parking and roadway areas of shopping centers close to the stores, etc. In “Heavy Traffic and Pollutant Load” areas a SNOUT in every structure is indicated (STSR 1:1). The exception will be where an inlet can not be maintained. In this case, and where additional treatment is desired, non-inlet polishing structures can be added to the drainage network prior to discharge (e.g. with a cover not a grate thus it receives no surface flow). An oil absorbing boom may also be deployed in structures that will receive heavy hydrocarbon loading and flow deflectors may be added to a polishing structure to increase solids removals. Moderate Traffic and Pollutant Loading Applications (STSR 1:2): This includes office buildings, multi-residential complexes, schools (other than bus areas), most shopping mall parking areas, mixed retail commercial facilities, municipal/government buildings, athletic/entertainment/recreational facilities, non-fast food restaurants, special event/remote parking areas, etc. In “Moderate Traffic and Pollutant Load” areas a SNOUT in at least every other structure is indicated (STSR 1:2). The downstream structures (prior to discharge) are most critical, and oil absorbing booms may be useful if heavier hydrocarbon loading is expected. Flow deflectors may be employed in a polishing structure to increase solids separation. Low Traffic and Pollutant Loading Applications (STSR 1:3): This includes grassy or vegetated areas, single family residences, parks*, parking for offices within residences, flow excess from permeable paving areas, etc. In Low Traffic and Pollutant Load areas one SNOUT in every three structures may be adequate (STSR 1:3). The need for oil booms or flow deflectors is unlikely as such a need would indicate a Moderate or Heavy Pollutant load scenario. * If discharge in a park setting is to a “high-value” water body, additional treatment may be indicated even if it is otherwise defined as a low traffic low load area. STSR Note: A large site may have different STSR areas, just like it may have different runoff coefficients. For instance, a shopping mall may have an STSR of 1:1 in heavy traffic roadways and loading/unloading areas, but may have a STSR 1:2 in a remote parking area. Therefore apply the appropriate STSR to each area of the site to arrive at the total number of SNOUT equipped structures for the project. Design Recommendations for Individual Structures:  The SNOUT size will always be bigger than the nominal pipe size as the SNOUT must over the pipe OD (e.g. use an 18” SNOUT for 12” pipe).  As a rule of thumb, BMP, Inc. recommends minimum sump depths based on outlet pipe inside diameters of 2.5 to 3 times the outlet pipe size. (Special Note for Smaller Pipes: A minimum sump depth of 36 inches for all pipe sizes 12 inches ID or less, and 48 inches for pipe 15-18 inches ID is required if collection of finer solids is desired.)  The plan dimension of the structure should be up to 6 to 7 times the flow area of the outlet pipe.  Bio-Skirts (for hydrocarbon and bacteria reduction in any structure) and flow deflectors (for settleable solids in a final polishing structure) can increase pollutant removals. Bio-Skirts are highly recommended for gas or vehicle service stations, convenience stores, restaurants, loading docks, marinas, or high traffic applications. Bio-Skirts are most effective when used in conjunction with a SNOUT.  The “R” series SNOUTs are available for round manhole type structures of up to 72” ID with pipes up to 50” OD; the “F” series SNOUTs are available for flat walled box type structures for pipes up to 94” OD; the “NP” series SNOUTs are available for PVC Nyloplast® type structures up to 30” ID. Further structural design guidelines including CAD drawings, hydraulic spreadsheets, and site inspection and maintenance field reports and installation inspection sheets are available from BMP, Inc. APPLICATION DRAWINGS: Contact Information: Please contact us if we can offer further assistance. 53 Mt. Archer Rd. Lyme, CT 06371. Technical Assistance: T. J. Mullen (800-504-8008, tjm@bmpinc.com) or Lee Duran (888-434-0277). Website: www.bmpinc.com The SNOUT® is protected by: US PATENT # 6126817 CANADIAN PATENT # 2285146 SNOUT® is a registered trademark of Best Management Products, Inc. Nyloplast® is a registered trademark of ADS Structures, Inc. FP-1 36 of 45 Stamp: Checked: Drawn: CVT Proj. #: SOUTHEAST COMMUNITY PARK 05.12.2015 Project Development Plan Issue Record: Revisions: Consultants: Landscape Architect 3350 Kechter Road, Fort Collins CO, 80528 1200 Bannock St. Denver, CO 80204 Tel. 303 571.0053 Fax 303 425.0438 Ripley Design Inc. (970) 224-5828 970-484-0117 RB+B Architects, Inc. Architect Civil Engineer Interwest Design Group (970) 674-3300 215 North Mason Street Fort Collins, Colorado 80521 tel: 970.221.6360 www.fcgov.com/parkplanning/ 2-13-0010 Mechanical Engineer Abrahamson Engineering, Inc. 970-221-2569 Lighting Design Clanton & Associates 303-530-7229 Irrigation Design Hines Inc 970-282-1800 95% CONSTRUCTION DOCUMENTS Drawing Name: 09.02.2015 Project Development Plan 12.04.2015 90% Construction Documents 02.09.2016 95% Construction Documents 02.10.2016 Final Development Plan NOTES 1. ALL PROPOSED IMPROVEMENTS LOCATED INSIDE OF THE McCLELLAND'S CREEK PROPOSED FLOODPLAIN SHALL BE AT GRADE. THE NORTHERN MOST PORTION OF THE COMMUNITY GARDENS AREA WILL CONTAIN AT-GRADE PLANTINGS ONLY, NO STRUCTURES OR RAISED PLANTER BEDS WILL BE ALLOWED. 09.02.2015 Project Development Plan 12.04.2015 90% Construction Documents 02.09.2016 95% Construction Documents 03.23.2016 Final Development Plan