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HomeMy WebLinkAboutHARMONY COTTAGES - FDP - FDP160019 - SUBMITTAL DOCUMENTS - ROUND 1 - DRAINAGE REPORTPRELIMINARY DRAINAGE REPORT Harmony Cottages Prepared for: Habitat for Humanity 4001 S. Taft Hill Road Fort Collins, CO 80525 (970) 223-4522 Prepared by: Interwest Consulting Group 1218 West Ash, Suite A Windsor, Colorado 80550 (970) 674-3300 April 12, 2016 Job Number 1255-028-00 ii April 12, 2016 Ms. Heather McDowell City of Fort Collins Stormwater 700 Wood Street Fort Collins, CO 80522-0580 RE: Final Drainage Report for Harmony Cottages Dear Heather, I am pleased to submit for your review and approval, this Final Drainage Report for the Harmony Cottages 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. I appreciate your time and consideration in reviewing this submittal. Please call if you have any questions. Sincerely, Skylar Brower, P.E. Colorado Professional Engineer No. 44248 iii TABLE OF CONTENTS TABLE OF CONTENTS ............................................................................................................ iii 1. GENERAL LOCATION AND DESCRIPTION ................................................................ 1 1.1 Location ........................................................................................................................... 1 1.2 Description of Property ................................................................................................. 1 1.3 Floodplain Submittal Requirements ............................................................................. 2 2. DRAINAGE BASINS AND SUB-BASINS .......................................................................... 2 2.1 Major Basin Description ................................................................................................ 2 2.2 Sub-basin Description .................................................................................................... 2 3. DRAINAGE DESIGN CRITERIA ...................................................................................... 3 3.1 Regulations ...................................................................................................................... 3 3.2 Directly Connected Impervious Area (DCIA) Discussion .......................................... 3 3.3 Development Criteria Reference and Constraints ...................................................... 4 3.4 Hydrological Criteria ..................................................................................................... 5 3.5 Hydraulic Criteria .......................................................................................................... 5 3.6 Floodplain Regulations Compliance ............................................................................. 6 3.7 Modifications of Criteria ............................................................................................... 6 4. DRAINAGE FACILITY DESIGN ....................................................................................... 6 4.1 General Concept ............................................................................................................. 6 4.2 Specific Details ................................................................................................................ 6 4.3 Stormwater Detention .................................................................................................... 8 4.4 Water Quality Treatment .............................................................................................. 8 5. CONCLUSIONS .................................................................................................................. 10 5.1 Compliance with Standards ........................................................................................ 10 5.2 Drainage Concept ......................................................................................................... 10 6. REFERENCES .................................................................................................................... 10 APPENDIX VICINITY MAP AND DRAINAGE PLAN .............................................................................. A HYDROLOGIC COMPUTATIONS .......................................................................................... B HYDRAULIC COMPUTATIONS (PROVIDED AT FINAL) ................................................. C STORMWATER DETENTION POND ANALYSIS ............................................................... D WATER QUALITY AND LID INFORMATION ..................................................................... E EXCERPTS FROM REFERENCE REPORTS......................................................................... F SOIL REPORT AND FEMA INFORMATION ....................................................................... G 1 1. GENERAL LOCATION AND DESCRIPTION 1.1 Location The Harmony Cottages development is located in Fort Collins. It is located in the Southwest ¼ of Section 34, Township 7 North, Range 69 West of the 6th Principal Meridian in the City of Fort Collins, Larimer County, Colorado. Please refer to the vicinity map in Appendix A. The project site is located in the southeast corner of Harmony Road (County Road 38E) and Taft Hill Road in southwest Fort Collins, Colorado. The site is bounded by Harmony Road on the north and east, Taft Hill Road on the west, and The Overlook at Woodridge Fourth Filing on the south. Adjacent to the northeast corner of the site is a water pump station owned by the Fort Collins-Loveland Water District (FCLWD). The legal description of the site is a replat of Lots 1 and 2, Innovation Island. 1.2 Description of Property The project is a site development of a Habitat for Humanity neighborhood. The property consists of 4.45 acres of land and lots will be designed for single family and duplex housing units with private drive through aisles and parking areas. The site currently consists of open space and is sparsely vegetated with native plants and grasses. Offsite flow contributing to the site includes adjacent public street right-of-way and the FCLWD parcel. The soils in the area are predominately Altan-Satanta loams (86.3%), 0-3 percent slopes (soil number 3), Hydrologic Soil Group B and Fort Collins loam (13.7%), 0-3 percent slopes (soil number 35), Hydrologic Soil Group C as reported in the Soil Survey of Larimer County Area, Colorado. According to FEMA Panel 08069C1000F there are no mapped FEMA Floodways on this property. Please refer to Appendix G for the NRCS soils report and FEMA information. 2 1.3 Floodplain Submittal Requirements Because the project is not within any FEMA or City of Fort Collins mapped floodway, a Floodplain Submittal is not required and a “City of Fort Collins Floodplain Review Checklist for 50% Submittals” has not been included with this report. 2. DRAINAGE BASINS AND SUB-BASINS 2.1 Major Basin Description The site is located on the upper end of the Mail Creek Drainage Basin. This site is known as sub-basin 89 in the master drainage plan and there are no offsite flows that pass through this site. The impervious area for the site was assumed to be 95% in the master plan. Excerpts from the “Mail Creek Basin Master Drainage Plan Hydrology Technical Appendix” are included in Appendix F of this report. This site is also included in the “Master Drainage Study for Woodridge” (1991) and the “Final Drainage and Erosion Control Study for the Overlook at Woodridge, Fourth Filing” (1995). In the Final Drainage Report for the Overlook at Woodridge Fourth Filing, this site is known as Basin 1 and 2A. These basins were considered to be neighborhood commercial sites with a C-value of 0.85. Fully developed commercial flows from this site were considered in the stormwater system plan design for the Overlook at Woodridge. Excerpts from the “Final Drainage and Erosion Control Study for the Overlook at Woodridge, Fourth Filing” report are included in Appendix F of this report. 2.2 Sub-basin Description The southern portion of the site drains to an existing swale which carries stormwater runoff along the south property line to a depression and into a concrete pipe located in Tract A of the Overlook at Woodridge. The remaining portion of the site drains via overland flow to the curb and gutter along Harmony Road and into two existing 15’ type R inlets on the south side of Harmony Road. All of the stormwater runoff from the site is conveyed to the existing stormwater conveyance system in Harmony Road which passes to the existing concrete lined drainage channel north of Seneca Drive and then to the existing regional detention pond located adjacent to Webber Middle School. 3 3. DRAINAGE DESIGN CRITERIA 3.1 Regulations This report was prepared to meet or exceed the “City of Fort Collins Storm Drainage Design Criteria Manual” specifications. Where applicable, the criteria established in the “Urban Storm Drainage Criteria Manual” (UDFCD), developed by the Denver Regional Council of Governments, has been used. 3.2 Directly Connected Impervious Area (DCIA) Discussion Urban Drainage and Flood Control District (UDFCD) recommends a Four Step Process for receiving water protection that focuses on reducing runoff volumes, treating the water quality capture volume (WQCV), stabilizing drainageways and implementing long-term source controls. The Four Step Process applies to the management of smaller, frequently occurring events. Step 1: Employ Runoff Reduction Practices To reduce runoff peaks, volumes, and pollutant loads from urbanizing areas, implement Low Impact Development (LID) strategies, including Minimizing Directly Connected Impervious Areas (MDCIA). Runoff for the northern portion of the site will be routed to a rain garden which slows runoff and promotes infiltration. Runoff from the southern portion of the site will be routed through a grass swale with an underdrain and a second rain garden thereby slowing runoff, increasing time of concentration, and also promoting infiltration. Step 2: Implement BMPs that Provide a Water Quality Capture Volume with Slow Release 92% of the proposed impervious area will be routed through an LID facility; therefore, no additional water quality capture volume is proposed with these improvements. 4 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 storm system, bank stabilization is unnecessary with this project. Step 4: Implement Site Specific and Other Source Control BMPs Proactively controlling pollutants at their source by preventing pollution rather than removing contaminants once they have entered the stormwater system or receiving waters is important when protecting storm systems and receiving waters. This can be accomplished through site specific needs such as construction site runoff control, post- construction runoff control and pollution prevention / good housekeeping. It will be the responsibility of the contractor to develop a procedural best management practice for the site. 3.3 Development Criteria Reference and Constraints The runoff from this site has been routed to conform to the requirements of the City Stormwater Department and the Mail Creek Basin Master Drainage Plan. Water quality capture volume will be provided on site. The impervious area for the site was assumed to be 95% in the master plan. The proposed weighted average impervious area for the proposed site is 50% which is less than the master plan. Fully developed commercial flows from this site were considered in the stormwater system plan design for the Overlook at Woodridge. The correlating basins 1 and 2A were considered to be neighborhood commercial sites with a C-value of 0.85. The proposed weighted average C-value of the proposed site is 0.58 which is less than the original design and therefore, downstream stormwater system will have capacity. Please refer to supporting documentation in Appendix F. Correlating Basin ID %I C-value Master Plan 89 95 - Woodridge 4th 1, 2A - 0.85 Site A, B, C, D & E 54 0.58 5 Runoff reduction practices (LID techniques) are also required. No less than seventy-five percent of any newly added impervious area must be treated using one or a combination of LID techniques. The project adds 110,940 sf of new impervious area. Using the rain garden LID technique, 102,020 sf of new impervious area (92%) will be treated which exceeds the 75% requirement. Please refer to Appendix E for LID calculations and information. 3.4 Hydrologic Criteria Runoff computations were prepared for the 2- and 10-year minor and 100-year major storm frequency utilizing the rational method. The storm systems were sized to convey the 10-year minor event. The 100-year major event will flow overland without impacting any structures to the existing storm structures located in Harmony Road designated at design point #10 and #21. All hydrologic calculations associated with the basins are included in Appendix B of this report. Standard Form 8 (SF-8) provides time of concentration calculations for all sub- basins. Standard Form 9 (SF-9) provides a summary of the design flows for all Sub- basins and Design Points associated with this site. 3.5 Hydraulic Criteria All hydraulic calculations have been prepared in accordance with the City of Fort Collins Drainage Criteria. The storm systems were sized to convey the 10-year minor event. Therefore, hydraulic computations were prepared for the 10-year minor storm frequency. The 100-year major event will exceed the capacity of the storm system (curb cuts, sidewalk culverts, storm pipe) and will flow overland without impacting any structures to the existing storm structures located in Harmony Road designated at design point #10 and #21. 6 3.6 Floodplain Regulations Compliance The project is not within any FEMA or City of Fort Collins mapped floodway; therefore, Floodplain Regulations Compliance is not required. 3.7 Modifications of Criteria There are no Modifications of Criteria at this time. 4. DRAINAGE FACILITY DESIGN 4.1 General Concept The proposed site generally follows the existing drainage patterns and is divided into five major drainage basins. Five off site drainage basins have also been delineated which – in addition to the site drainage basins - drain to the existing storm system in Harmony Road. 4.2 Specific Details A summary of the drainage patterns within each basin is provided in the following paragraphs. Please refer to Appendix A for the drainage plan. Basin A is 1.65 acres and includes the southern portion of the proposed site. Runoff is conveyed via overland flow to the proposed grass swale that runs west to east along the southern property boundary. This south swale discharges into Rain Garden A in the southeast corner of the property located at design point a. The outlet pipe for the rain garden discharges to the existing storm drain inlet #21 located on the south side of Harmony Road. Basin B is 2.24 acres and includes the northern portion of the. This basin is conveyed via overland flow to the private drive and then continues via gutter flow to Rain Garden B located at the southwest corner of the intersection of the driveway and Harmony Road. The outlet pipe for the rain garden discharges to the existing 15’ Type R inlet #10 located on the south side of Harmony Road. Basin C is 0.12 acres and includes the northern most portion of the private drive. Runoff 7 is conveyed via curb and gutter to a 4’ cub opening and concrete sidewalk culvert that drains into Rain Garden B. Basin D is 0.20 acres and includes the northern half of the roof area for three duplex units located adjacent to Harmony Road. The roof runoff, in addition to any runoff generated by the landscape area between the units and the Harmony Road ROW, will sheet flow across the parkway and be intercepted by the existing roadway curb and gutter. Runoff is conveyed via gutter flow to the existing 15’ Type R inlet #10 in Harmony Road. Basin E is 0.21 acres and includes the northern half of the roof area for four duplex units located adjacent to Harmony Road. The roof runoff, in addition to any runoff generated by the landscape area between the units and the Harmony Road ROW, will sheet flow across the parkway and be intercepted by the existing roadway curb and gutter. Runoff is conveyed via gutter flow to the existing 15’ Type R inlet #21 in Harmony Road. Basin OS-1 is 0.40 acres and includes the existing landscape area in the Taft Hill ROW as well as the property located in the southeast corner of Taft Hill and Harmony which is owned by FCLWD. Any runoff generated in this basin will sheet flow to the east where it will be intercepted by a concrete pan or grass swale located at the property line of the project. The runoff will then be conveyed via gutter flow to Rain Garden B and ultimately to inlet #10. Basin OS-2 is 0.12 acres and includes the existing landscape area in the Taft Hill ROW. Any runoff generated in this basin will sheet flow to the east where it will be intercepted by a concrete pan which drains into the grass swale located along the southern portion of the property. This grass swale drains to Rain Garden A and ultimately to inlet #21. Basin OS-3 is 0.32 acres and includes the north half of the roofs of 5 lots from the Overlook at Woodridge, P.U.D. Fourth Filing adjacent to basin A. This basin sheet flows to the southern grass swale. Basin OS-10 is 0.80 acres and includes the south half of the roadway of Harmony Road as well as the parkway and existing sidewalk adjacent to basin B & D. This basin is conveyed via gutter flow to the existing 15’ Type R inlet #10 in Harmony Road. 8 Basin OS-21 is 0.34 acres and includes the south half of the roadway of Harmony Road as well as the parkway and existing sidewalk adjacent to basin E. This basin is conveyed via gutter flow to the existing 15’ Type R inlet #21 in Harmony Road. 4.3 Stormwater Detention Developed commercial flows from this site were accounted for in the design of the storm drainage detention pond for the Overlook at Woodridge Fourth Filing (1995). Since the time that the Final Drainage Study for the Overlook was completed, the City of Fort Collins (CFC) has modified their stormwater design criteria to include stormwater quality enhancement requirements and the use of a larger design storm based on a 1998 precipitation study. The peak discharge using the old rainfall data for the site only (4.45 acres) and a C 100-year value of 1.00 was calculated to be 40.1-cfs. The required detention volume under the new rainfall conditions with a release rate set to the peak discharge under the old rainfall conditions and a developed C 100-year value of 0.70 was calculated. The result was a detention requirement of -0.04 ac-ft with a storm duration of 5 minutes. Therefore, adequate stormwater detention is being provided and additional detention is not required based on the increase in the design rainfall rates. 4.4 Water Quality Treatment Water quality enhancement is being provided for fully developed conditions. Three water quality enhancement measures will be used on this site. 92% of the new impervious area on site will be directed to an LID facility. Therefore, no water quality capture volume is required for this site. The first water quality enhancement measure is the rain garden in the southeast corner of the site which is referred to as rain garden A. The rain garden is a depressed landscape area designed to capture and infiltrate the water quality capture volume. This area has an average depth of 12”, has a flat bottom and will include landscape plantings in 12” depth of a sand media mixture. Water will be held in the depressed area and slowly drain through the sand media and then hit a 4” perforated pipe in gravel bedding which will discharge ultimately to the existing storm system in Harmony Road. This rain garden will treat 0.024 ac-ft (1,063 cf) of the water quality capture volume. 9 The second water quality enhancement measure is the rain garden adjacent to Harmony and the main driveway which is referred to as rain garden B. The rain garden is a depressed landscape area designed to capture and infiltrate the water quality capture volume. This area has an average depth of 12”, has a flat bottom and will include landscape plantings in 12” depth of a sand media mixture. Water will be held in the depressed area and slowly drain through the sand media and then hit a 4” perforated pipe in gravel bedding which will discharge ultimately to the existing storm system in Harmony Road. This rain garden will treat 0.046 ac-ft (2,016 cf) of the water quality capture volume. The third water quality enhancement measure is the grass swale located along the south property line. The swale has been designed to have a low longitudinal slope in order to convey flow in a slow and shallow manner promoting sedimentation and filtration and limiting erosion. The bottom of the swale is not concrete lined in order to further enhance pollutant removal. The swale will be constructed with a 4” underdrain in order to minimize standing water in the swale. There is a small portion of the site immediately adjacent to Harmony Road which will not pass through a water quality feature but will flow directly to the street gutter and into the stormwater system. This area is accounted for in basin D & E. The majority of this area is landscaped with grass and plantings and only a small amount of impervious area from the sidewalk and roof is included. Since the source of the majority of pollutants in stormwater runoff comes from driveway and parking areas, this small amount of untreated runoff should have a negligible effect on the overall pollutant load. Several off- site areas will be conveyed through the site and treated on-site including the FCLWD parcel and the area adjacent to Taft Hill Road and this property. 10 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. 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 impervious areas. Conveyance elements have been designed to pass required flows and to minimize future maintenance. If, at the time of construction, groundwater is encountered, a Colorado Department of Health Construction Dewatering Permit will be required. 6. REFERENCES 1. City of Fort Collins, “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 2015. 3. Ayers Associates, “Alternative Analysis for the Design of the Mason Street Outfall”, dated November 2010. 4. RBD, Inc. Engineering Consultants, “Preliminary/Master Drainage Study for Woodridge”, dated December 2, 1991. 5. RBD, Inc. Engineering Consultants, “Final Drainage and Erosion Control Study for the Overlook at Woodridge Fourth Filing, Phase One”, dated June 14, 1995. A APPENDIX A VICINITY MAP AND DRAINAGE PLAN RAIN GARDEN A RAIN GARDEN B 0 40' 40 20 40 80 SCALE: 1" = PREPARED FOR PROJ. NO. DATE: SCALE (H): SCALE (V): CHECKED BY: DESIGNED BY: PROJECT NAME HARMONY COTTAGES DRAINAGE PLAN 04/13/16 1"=40' N/A SB RA 1255-028-00 12 of 19 HABITAT FOR HUMANITY 4001 S. TAFT HILL ROAD FORT COLLINS, CO 80525 PHONE: 970.223.4522 PROPOSED DRAINAGE BASIN DIVIDE LINE MINOR STORM RUNOFF COEFFICIENT DRAINAGE BASIN AREA DRAINAGE BASIN NUMBER LEGEND PROPOSED DIRECTION OF OVERLAND FLOW DESIGN POINT NOTES: 1. SEE LANDSCAPE PLAN FOR PLANTINGS THROUGHOUT THE SITE. 2. THE TOP OF FOUNDATION ELEVATION SHOWN IS HIGHER THAN THE MINIMUM ELEVATION REQUIRED FOR PROTECTION FROM THE 100-YR STORM. 3. EROSION CONTROL MEASURES TO BE SHOWN DURING FINAL COMPLIANCE. PRELIMINARY NOT FOR CONSTRUCTION B APPENDIX B HYDROLOGIC COMPUTATIONS Interwest Consulting Group RUNOFF COEFFICIENTS & % IMPERVIOUS LOCATION: Harmony Cottages PROJECT NO: 1255-028-00 COMPUTATIONS BY: sb DATE: 4/13/2016 Recommended Runoff Coefficients from Table RO-11 of City of Fort Collins Stormwater Code, Volume I Recommended % Impervious from Table RO-3 Urban Storm Drainage Criteria Manual, Volume I Type B Soils Runoff % coefficient Impervious C Streets, parking lots (asphalt): 0.95 100 Sidewalks (concrete): 0.95 96 Roofs: 0.95 90 Pavers: 0.50 40 Lawns, sandy soil (Flat <2%) : 0.10 0 SUBBASIN TOTAL TOTAL ROOF PAVED PAVERS SIDEWALK LANDSCAPE RUNOFF % DESIGNATION AREA AREA AREA AREA AREA AREA AREA COEFF. Impervious REMARKS (ac.) (sq.ft) (sq.ft) (sq.ft) (sq.ft) (sq.ft) (sq.ft) (C) Existing Lot 4.45 193,839 0 0 0 0 193,839 0.10 0 Proposed Lot 4.45 193,839 56,858 43,917 0 9,275 83,789 0.58 54 1, 2A 6.54 0.85 89 5.90 95 Equations - Calculated C coefficients & % Impervious are area weighted C = Σ (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 BASED ON MASTER DRAINAGE PLAN BASED ON WOODRIDGE 4TH FILING Final FLOW(04-13-16).xls Interwest Consulting Group RUNOFF COEFFICIENTS & % IMPERVIOUS LOCATION: Harmony Cottages PROJECT NO: 1255-028-00 COMPUTATIONS BY: sb DATE: 4/13/2016 Recommended Runoff Coefficients from Table RO-11 of City of Fort Collins Stormwater Code, Volume I Recommended % Impervious from Table RO-3 Urban Storm Drainage Criteria Manual, Volume I Type B Soils Runoff % coefficient Impervious C Streets, parking lots (asphalt): 0.95 100 Sidewalks (concrete): 0.95 96 Roofs: 0.95 90 Gravel or Pavers: 0.50 40 Lawns, sandy soil (Flat <2%) : 0.10 0 SUBBASIN TOTAL TOTAL ROOF PAVED SIDEWALK LANDSCAPE RUNOFF % DESIGNATION AREA AREA AREA AREA AREA AREA COEFF. Impervious REMARKS (ac.) (sq.ft) (sq.ft) (sq.ft) (sq.ft) (sq.ft) (C) A 1.65 72,075 20,822 13,800 1,517 35,936 0.53 47 B 2.24 97,566 27,902 26,867 6,525 36,272 0.63 60 C 0.12 5,368 714 3,250 703 701 0.84 85 D 0.20 8,801 3,750 0 170 4,881 0.48 40 E 0.21 9,333 3,670 0 360 5,303 0.47 39 OS-10 0.80 34,905 0 21,225 3,455 10,225 0.70 70 OS-21 0.34 14,942 0 9,234 1,595 4,113 0.72 72 OS-1 0.40 17,591 0 0 120 17,471 0.11 1 OS-2 0.12 5,084 0 0 150 4,934 0.13 3 OS-3 0.49 21,503 0.58 55 Equations - Calculated C coefficients & % Impervious are area weighted C = Σ (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 BASED ON WOODRIDGE 4TH FILING Final FLOW(04-13-16).xls Interwest Consulting Group STANDARD FORM SF-2 TIME OF CONCENTRATION - 2 and 10 YR LOCATION: Harmony Cottages PROJECT NO: 1255-028-00 COMPUTATIONS BY: sb DATE: 4/13/2016 2 and 10-yr storm Cf = 1.00 from Table RO-12 of City of Fort Collins Stormwater Code, Volume I 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 1.65 0.53 20 2.0 3.8 650 1.8 0.022 1.9 5.6 9.4 670 13.7 9.4 b B 2.24 0.63 50 2.0 4.9 650 1.5 0.016 2.5 4.4 9.3 700 13.9 9.3 b C 0.12 0.84 26 2.0 2.0 115 1.7 0.016 2.6 0.7 2.7 141 10.8 5.0 10 D 0.20 0.48 20 2.0 4.1 0 0.0 0 0.0 0.0 0.0 20 10.1 5.0 21 E 0.21 0.47 20 2.0 4.2 0 0.0 0 0.0 0.0 0.0 20 10.1 5.0 10 OS-10 0.80 0.70 25 2.0 3.0 575 0.6 0.016 1.6 6.2 9.1 600 13.3 9.1 21 OS-21 0.34 0.72 25 2.0 2.9 240 0.6 0.016 1.6 2.6 5.4 265 11.5 5.4 10 B+C+D+OS-10+OS-1 3.77 0.59 90 1.5 7.9 655 1.4 0.016 2.4 4.6 12.5 745 14.1 12.5 21 A+E+OS-1+OS-2+OS-21 3.11 0.41 20 2.0 4.6 935 1.4 0.03 1.3 12.4 17.0 955 15.3 15.3 b OS-1 0.40 0.11 85 2.0 13.6 0 0.0 0 0.0 0.0 0.0 85 10.5 5.0 b OS-2 0.12 0.13 40 4.0 7.3 0 0.0 0 0.0 0.0 0.0 40 10.2 5.0 a OS-3 0.49 0.58 20 2.0 3.5 600 1.8 0.022 2.0 5.1 8.6 620 13.4 8.6 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 Final FLOW(04-13-16).xls Interwest Consulting Group STANDARD FORM SF-2 TIME OF CONCENTRATION - 100 YR LOCATION: Harmony Cottages PROJECT NO: 1255-028-00 COMPUTATIONS BY: sb DATE: 4/13/2016 100-yr storm Cf = 1.25 from Table RO-12 of City of Fort Collins Stormwater Code, Volume I 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 1.65 0.53 0.66 20 2.0 2.9 650 1.8 0.022 1.9 5.6 8.5 670 13.7 8.5 b B 2.24 0.63 0.79 50 2.0 3.2 650 1.5 0.016 2.5 4.4 7.6 700 13.9 7.6 b C 0.12 0.84 1.00 26 2.0 0.8 115 1.7 0.016 2.6 0.7 1.5 141 10.8 5.0 10 D 0.20 0.48 0.60 20 2.0 3.3 0 0.0 0 0.0 0.0 3.3 20 10.1 5.0 21 E 0.21 0.47 0.58 20 2.0 3.4 0 0.0 0 0.0 0.0 3.4 20 10.1 5.0 10 OS-10 0.80 0.70 0.88 25 2.0 1.7 575 0.6 0.016 1.6 6.2 7.8 600 13.3 7.8 21 OS-21 0.34 0.72 0.90 25 2.0 1.5 240 0.6 0.016 1.6 2.6 4.1 265 11.5 5.0 10 B+C+D+OS-10+OS-1 3.77 0.59 0.74 90 1.5 5.6 655 1.4 0.016 2.4 4.6 10.2 745 14.1 10.2 21 A+E+OS-1+OS-2+OS-21 3.11 0.41 0.51 20 2.0 3.9 935 1.4 0.03 1.3 12.4 16.3 955 15.3 15.3 b OS-1 0.40 0.11 0.13 85 2.0 13.2 0 0.0 0 0.0 0.0 13.2 85 10.5 10.5 b OS-2 0.12 0.13 0.16 40 4.0 7.0 0 0.0 0 0.0 0.0 7.0 40 10.2 7.0 a OS-3 0.49 0.58 0.73 20 2.0 2.5 600 1.8 0.022 2.0 5.1 7.6 620 13.4 7.6 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 Final FLOW(04-13-16).xls Interwest Consulting Group RATIONAL METHOD PEAK RUNOFF (City of Fort Collins, 2-Yr Storm) LOCATION: Harmony Cottages PROJECT NO: 1255-028-00 COMPUTATIONS BY: sb DATE: 4/13/2016 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 1.65 0.53 9.4 2.28 2.0 2.0 Rain Garden A b B 2.24 0.63 9.3 2.29 3.3 3.3 Rain Garden B b C 0.12 0.84 5.0 2.85 0.3 0.3 Rain Garden B 10 D 0.20 0.48 5.0 2.85 0.3 0.3 Ex Inlet #10 21 E 0.21 0.47 5.0 2.85 0.3 0.3 Ex Inlet #21 10 OS-10 0.80 0.70 9.1 2.31 1.3 1.3 Ex Inlet #10 21 OS-21 0.34 0.72 5.4 2.74 0.7 0.7 Ex Inlet #21 10 B+C+D+OS-10+OS-1 3.77 0.59 12.5 2.03 4.5 4.5 Ex Inlet #10 21 A+E+OS-1+OS-2+OS-21 3.11 0.41 15.3 1.85 2.4 2.4 Ex Inlet #21 b OS-1 0.40 0.11 5.0 2.85 0.1 0.1 Rain Garden B b OS-2 0.12 0.13 5.0 2.85 0.0 0.0 Rain Garden A a OS-3 0.49 0.58 8.6 2.36 0.7 0.7 Rain Garden A 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 Final FLOW(04-13-16).xls Interwest Consulting Group RATIONAL METHOD PEAK RUNOFF (City of Fort Collins, 10-Yr Storm) LOCATION: Harmony Cottages PROJECT NO: 1255-028-00 COMPUTATIONS BY: sb DATE: 4/13/2016 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 1.65 0.53 9.4 3.89 3.4 3.4 Rain Garden A b B 2.24 0.63 9.3 3.91 5.6 5.6 Rain Garden B b C 0.12 0.84 5.0 4.87 0.5 0.5 Rain Garden B 10 D 0.20 0.48 5.0 4.87 0.5 0.5 Ex Inlet #10 21 E 0.21 0.47 5.0 4.87 0.5 0.5 Ex Inlet #21 10 OS-10 0.80 0.70 9.1 3.94 2.2 2.2 Ex Inlet #10 21 OS-21 0.34 0.72 5.4 4.68 1.1 1.1 Ex Inlet #21 10 B+C+D+OS-10+OS-1 3.77 0.59 12.5 3.46 7.7 7.7 Ex Inlet #10 21 A+E+OS-1+OS-2+OS-21 3.11 0.41 15.3 3.15 4.0 4.0 Ex Inlet #21 b OS-1 0.40 0.11 5.0 4.87 0.2 0.2 Rain Garden B b OS-2 0.12 0.13 5.0 4.87 0.1 0.1 Rain Garden A a OS-3 0.49 0.58 8.6 4.04 1.2 1.2 Rain Garden A 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 Final FLOW(04-13-16).xls Interwest Consulting Group RATIONAL METHOD PEAK RUNOFF (City of Fort Collins, 100-Yr Storm) LOCATION: Harmony Cottages PROJECT NO: 1255-028-00 COMPUTATIONS BY: sb DATE: 4/13/2016 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 1.65 0.66 8.5 8.25 9.0 9.0 Rain Garden A b B 2.24 0.79 7.6 8.59 15.2 15.2 Rain Garden B b C 0.12 1.00 5.0 9.95 1.2 1.2 Rain Garden B 10 D 0.20 0.60 5.0 9.95 1.2 1.2 Ex Inlet #10 21 E 0.21 0.58 5.0 9.95 1.2 1.2 Ex Inlet #21 10 OS-10 0.80 0.88 7.8 8.52 6.0 6.0 Ex Inlet #10 21 OS-21 0.34 0.90 5.0 9.95 3.1 3.1 Ex Inlet #21 10 B+C+D+OS-10+OS-1 3.77 0.74 10.2 7.70 21.4 21.4 Ex Inlet #10 21 A+E+OS-1+OS-2+OS-21 3.11 0.51 15.3 6.44 10.2 10.2 Ex Inlet #21 b OS-1 0.40 0.13 10.5 7.62 0.4 0.4 Rain Garden B b OS-2 0.12 0.16 7.0 8.83 0.2 0.2 Rain Garden A a OS-3 0.49 0.73 7.6 8.60 3.1 3.1 Rain Garden A 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 Final FLOW(04-13-16).xls SUMMARY DRAINAGE SUMMARY TABLE Design Tributary Area C (10) C (100) tc (10) tc (100) Q(2)tot Q(10)tot Q(100)tot Sub-basin REMARKS Point (ac) (min) (min) (cfs) (cfs) (cfs) a A 1.65 0.53 0.66 9.4 8.5 2.0 3.4 9.0 Rain Garden A b B 2.24 0.63 0.79 9.3 7.6 3.3 5.6 15.2 Rain Garden B b C 0.12 0.84 1.00 5.0 5.0 0.3 0.5 1.2 Rain Garden B 10 D 0.20 0.48 0.60 5.0 5.0 0.3 0.5 1.2 Ex Inlet #10 21 E 0.21 0.47 0.58 5.0 5.0 0.3 0.5 1.2 Ex Inlet #21 10 OS-10 0.80 0.70 0.88 9.1 7.8 1.3 2.2 6.0 Ex Inlet #10 21 OS-21 0.34 0.72 0.90 5.4 5.0 0.7 1.1 3.1 Ex Inlet #21 10 B+C+D+OS-10+OS-1 3.77 0.59 0.74 12.5 10.2 4.5 7.7 21.4 Ex Inlet #10 21 A+E+OS-1+OS-2+OS-21 3.11 0.41 0.51 15.3 15.3 2.4 4.0 10.2 Ex Inlet #21 b OS-1 0.40 0.11 0.13 5.0 10.5 0.1 0.2 0.4 Rain Garden B b OS-2 0.12 0.13 0.16 5.0 7.0 0.0 0.1 0.2 Rain Garden A a OS-3 0.49 0.58 0.73 8.6 7.6 0.7 1.2 3.1 Rain Garden A Page 11 ✁ ✂ ✄ ☎ ✂ ✆ ✝ ✞ ✁ ✄ ✟ ✝ ✓ ✁ ✔ ✄ ✕ ✂ ✖ ✗ ✠ ✘ ✂ ✙ ☎ ✚ ✡ ✛ ✜ ✂ ☛ ✘ ☞ ✗ ✌ ✢ ✍ ✣ ✎ ✤ ✏ ✤ ✗ ✥ ✦ ✗ ✦ ✧ ✗ ★ ✢ ✗ ✥ ✩ ✔ ✪ ✗ ✫ ✤ ✬ ✗ ★ ✭ ✮ ✣ ✯ ✰ ✥ ✗ ✰ ✰ ✱ ✔ ✖ ✯ ✗ ✰ ✁ ✡ ☎ ✑ ✒ ✒ ❅ ✺ ✵ ✿ ✳ ✶ ✵ ✹ ✵ ❆ ✺ ✸ ✻ ✲ ✼ ☛ ✶ ✲ ✳ ✞ ✴ ✽ ✡ ✲ ✸ ✵ ✲ ✶ ✼ ✾ ✷ ✶ ✸ ✸ ✿ ✵ ✾ ✿ ✼ ✵ ✄ ❂ ❀ ❃ ✶ ✶ ✸ ✸ ✼ ❄ ✶ ✿ ✷ ✳ ✺ ✾ ✵ ✲ ✳ ❁ ✶ ✶ ✵ ✵ ✁ ✶ ✞ ☎ ✹ ✠ ✵ ✿ ✷ ✶ ✿ ✺ ✳ ✴ ❂ ✿ ❇ ❁ ❁ ✶ ✾ ✿ ❇ ✽ ✳ ❂ ● ✶ ✺ ❊ ✾ ● ✿ ✶ ✳ ✻ ✲ ✷ ✲ ✸ ✿ ❇ ✸ ✾ ✼ ❂ ❆ ✽ ✿ ☞ ✲ ✷ ✴ ✿ ❇ ❇ ✷ ❍ ✶ ✲ ✴ ✾ ✲ ✸ ✶ ✲ ✼ ✲ ✸ ✽ ✶ ✵ ✶ ✲ ✴ ✵ ✏ ❈ ❋ ❏ ■ ❉ ❉ ❑ ✄ ✳ ✴ ✠ ▼ ✂ ☛ ✺ ✿ ❃ ✲ ❁ ✺ ✵ ✲ ❇ ✽ ❇ ✾ ✻ ✾ ✸ ● ✸ ✿ ✾ ✿ ✲ ● ✾ ✲ ❂ ✺ ✲ ✼ ❇ ✳ ✸ ❆ ✸ ✶ ✶ ✶ ✿ ✾ ✳ ✲ ❇ ☞ ✾ ✵ ✷ ✵ ✲ ✾ ✾ ✾ ✷ ✲ ✸ ✼ ❇ ✽ ✲ ✶ ✸ ✴ ❁ ✏ ✶ ✸ ▲ ❋ ❋ ■ ❉ ❑ ❑ ❀ ✲ ▼ ✸ ◆ ✶ ✵ ✲ ❖ ❄ ✼ ❍ ✶ ✲ ❂ ✸ ✶ ✶ ✾ ✲ ✶ ✵ ✸ ✿ ✶ ✵ ❈ ❉ ❑ ❀ ✹ ✁ ✡ ❇ ✼ ✲ ✳ ✲ ✽ ✿ ✴ ❍ ❇ ✸ ✷ ✶ ❁ ✷ ✷ ❄ ✸ ✲ ✷ ❇ ✶ ✵ ✴ ✺ ❇ ✷ ✳ ❍ ❃ ✴ ✲ ✶ ✵ ✸ ✴ ✴ ✂ ✲ ✸ ✸ ✶ ✶ ✲ ✲ ✵ ✵ ❆ ❉ ✎ ✎ ❑ ❑ ❉ ☞ ▼ ✆ ✑ P ✿ ✸ ✻ ✵ ✽ ✻ ✶ ● ✾ ✶ ✵ ✶ ✷ ✳ ✿ ✳ ✸ ✾ ✿ ✶ ❊ ✼ ❇ ✲ ✶ ✻ ✻ ❇ ✳ ❇ ❇ ✷ ✷ ✾ ✴ ✵ P P ❖ ✺ ✲ ✲ ✲ ✵ ❁ ✳ ✶ ✳ ✸ ✲ ✲ ✿ ✳ ✼ ❇ ❇ ❍ ❍ ✷ ✺ ✵ ✵ ✾ ❇ ✾ ✿ ✿ ✵ ✺ ✴ ✵ ✸ ✶ ✲ ✻ ✿ ❇ ✳ ✶ ✴ ✏ ❘ ◗ ◗ ❉ ✹ ✾ ✸ ❀ ✆ ✶ ✲ ✸ ✶ ✲ ❄ ✾ ✵ ❄ ✶ ✶ ❆ ✴ ❇ ☞ ❃ ✲ ✼ ◆ ✶ ✴ ✏ ✎ ❘ ❑ ❑ ❑ ✁ ☛ ☛ ✲ ✲ ✸ ✷ ✿ P P ✷ ❄ ✶ ✻ ✳ ✳ ✵ ✵ ✵ ✲ ❖ ❖ ✳ ✵ ✼ ✴ ✲ ❇ ✲ ✳ P ❍ ✴ ✶ ✲ ❍ ❍ ❇ ◆ ✵ ✵ ✵ ✷ ✷ ✿ ✿ ❇ ❇ ❈ ❈ ❑ ❑ ❑ ❑ ■ ✹ ✶ ✶ ✒ ✿ ❁ ✺ ✸ ✶ ✵ ✁ ✑ ● ❙ ✾ ✽ ✸ ✷ ✺ ❁ ✽ ✁ ✑ ● ❉ ✻ ✷ ✸ ❃ ✶ ✸ ✼ ✶ ✳ ✾ ✲ ❁ ✶ ✿ ❂ ❃ ✶ ✸ ❄ ✿ ✷ ✺ ✵ ✳ ✶ ✵ ✵ ✍ ❴ ❵ ❫ ❵  ❚ ❱ ❳ ❚ 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■ ❖ ❖ ❜ ❨ ❘ P ● ● ❱ ❲ ❱ ❍ ❵ ❊ ❙ ❘ ❏ ❧ ❙ P ✻ ✻ ✻ ✻ ✼ ✼ ▲ ♠ ✼ ✼ ♠ ❚ ❄ ❄ ❀ ❘ ❥ ❑ ✺ ❛ ❑ ❃ P ❙ P ❯ ❘ ■ ■ ● ■ ■ P ■ ❅ ❲ ❲ ◗ ❦ ❵ ❘ ■ ❨ ❭ ♥ ♥ ❘ ❧ ■ ❊ ❊ ❯ ❧ ❧ ❜ ❨ P ● ❱ ❱ ❍ ❊ ❙ ❏ ❧ ✻ ✻ ✻ ✻ ✼ ✼ ❨ ✽ ✼ ✼ ❨ ❨ ❄ ❄ ✂ ♦ ☎ ♣ ✎ ☛ q r s t ✉ ✈ ✇ ① ② ③ ④ ✏ ✑ ✟ ✖ ✖ ☛ ✖ ✔ ✌ ✝ ✞ ☛ ✟ ✖ ✟ ✑ ✕ ✝ ✍ ✍ ✝ q ✑ ⑤ C APPENDIX C HYDRAULIC CALCULATIONS STORM LINE A STORM LINE B Project Description Flow Element: Triangular 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) Discharge: 10.90 ft³/s Results Normal Depth: 0.96 ft Flow Area: 3.67 ft² Wetted Perimeter: 7.90 ft Top Width: 7.66 ft Critical Depth: 0.86 ft Critical Slope: 0.01811 ft/ft Velocity: 2.97 ft/s Velocity Head: 0.14 ft Specific Energy: 1.09 ft Froude Number: 0.76 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 Profile Headloss: 0.00 ft Downstream Velocity: 0.00 ft/s Upstream Velocity: 0.00 ft/s Normal Depth: 0.96 ft Critical Depth: 0.86 ft Channel Slope: 0.01000 ft/ft Critical Slope: 0.01811 ft/ft Worksheet for Harmony Cottages - South Swale Project Description Flow Element: Triangular Channel Friction Method: Manning Formula Solve For: Normal Depth Section Data Roughness Coefficient: 0.030 Channel Slope: 0.01000 ft/ft Normal Depth: 0.96 ft Left Side Slope: 4.00 ft/ft (H:V) Right Side Slope: 4.00 ft/ft (H:V) Discharge: 10.90 ft³/s South Swale Cross Section for Harmony Cottages - South Swale Culvert Calculator Report Harmony Cottages Private 15" Culvert x:\...\drainage\design\15-inch culvert.cvm 04/13/16 07:03:23 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 40.40 ft Headwater Depth/Height 1.12 Computed Headwater Elevation 40.40 ft Discharge 4.90 cfs Inlet Control HW Elev. 40.37 ft Tailwater Elevation 38.50 ft Outlet Control HW Elev. 40.40 ft Control Type Entrance Control Grades Upstream Invert 39.00 ft Downstream Invert 38.50 ft Length 35.00 ft Constructed Slope 0.014286 ft/ft Hydraulic Profile Profile S2 Depth, Downstream 0.71 ft Slope Type Steep Normal Depth 0.69 ft Flow Regime Supercritical Critical Depth 0.90 ft Velocity Downstream 6.81 ft/s Critical Slope 0.006548 ft/ft Section Section Shape Circular Mannings Coefficient 0.012 Section Material Corrugated HDPE (Smooth Interior) Span 1.25 ft Section Size 15 inch Rise 1.25 ft Number Sections 1 Outlet Control Properties Outlet Control HW Elev. 40.40 ft Upstream Velocity Head 0.42 ft Ke 0.20 Entrance Loss 0.08 ft Inlet Control Properties Inlet Control HW Elev. 40.37 ft Flow Control N/A Inlet Type Beveled ring, 33.7° bevels Area Full 1.2 ft² K 0.00180 HDS 5 Chart 3 M 2.50000 HDS 5 Scale B C 0.02430 Equation Form 1 Y 0.83000 Project: Inlet ID: Gutter Geometry (Enter data in the blue cells) Maximum Allowable Width for Spread Behind Curb TBACK = 5.0 ft Side Slope Behind Curb (leave blank for no conveyance credit behind curb) SBACK = 0.0200 ft. vert. / ft. horiz Manning's Roughness Behind Curb nBACK = 0.0130 Height of Curb at Gutter Flow Line HCURB = 6.00 inches Distance from Curb Face to Street Crown TCROWN = 24.0 ft Gutter Depression a = 2.00 inches Gutter Width W = 2.00 ft Street Transverse Slope SX = 0.0200 ft. vert. / ft. horiz Street Longitudinal Slope - Enter 0 for sump condition SO = 0.0050 ft. vert. / ft. horiz Manning's Roughness for Street Section nSTREET = 0.0160 Minor Storm Major Storm Max. Allowable Water Spread for Minor & Major Storm TMAX = 14.0 18.0 ft Max. Allowable Depth at Gutter Flow Line for Minor & Major Storm dMAX = 6.00 6.00 inches Allow Flow Depth at Street Crown (leave blank for no) X = yes Maximum Gutter Capacity Based On Allowable Water Spread Minor Storm Major Storm Gutter Cross Slope (Eq. ST-8) SW = 0.1033 0.1033 ft/ft Water Depth without Gutter Depression (Eq. ST-2) y = 3.36 4.32 inches Water Depth with a Gutter Depression d = 5.36 6.32 inches Allowable Spread for Discharge outside the Gutter Section W (T - W) TX = 12.0 16.0 ft Gutter Flow to Design Flow Ratio by FHWA HEC-22 method (Eq. ST-7) EO = 0.451 0.350 Discharge outside the Gutter Section W, carried in Section TX Q X = 2.8 5.9 cfs Discharge within the Gutter Section W (QT - Q X)QW = 2.3 3.2 cfs Discharge Behind the Curb (e.g., sidewalk, driveways, & lawns) QBACK = 0.0 0.0 cfs Maximum Flow Based On Allowable Water Spread QT = 5.0 9.1 cfs Flow Velocity Within the Gutter Section V = 3.3 3.8 fps V*d Product: Flow Velocity Times Gutter Flowline Depth V*d = 1.5 2.0 Maximum Gutter Capacity Based on Allowable Gutter Depth Minor Storm Major Storm Theoretical Water Spread TTH = 16.7 16.7 ft Theoretical Spread for Discharge outside the Gutter Section W (T - W) TX TH = 14.7 14.7 ft Gutter Flow to Design Flow Ratio by FHWA HEC-22 method (Eq. ST-7) EO = 0.378 0.378 Theoretical Discharge outside the Gutter Section W, carried in Section TX TH Q X TH = 4.7 4.7 cfs Actual Discharge outside the Gutter Section W, (limited by distance TCROWN)Q X = 4.7 4.7 cfs Discharge within the Gutter Section W (Qd - Q X)QW Project: Inlet ID: Design Information (Input) MINOR MAJOR Type of Inlet Type = Local Depression (additional to continuous gutter depression 'a' from 'Q-Allow') aLOCAL = 2.0 2.0 inches Total Number of Units in the Inlet (Grate or Curb Opening) No = 1 1 Warning 3 Length of a Single Unit Inlet (Grate or Curb Opening) Lo = 4.00 4.00 ft Width of a Unit Grate (cannot be greater than W from Q-Allow) Wo = N/A N/A ft Clogging Factor for a Single Unit Grate (typical min. value = 0.5) Cf-G = N/A N/A Clogging Factor for a Single Unit Curb Opening (typical min. value = 0.1) Cf-C = 0.10 0.10 Street Hydraulics: OK - Q < maximum allowable from sheet 'Q-Allow' MINOR MAJOR Design Discharge for Half of Street (from Sheet Q-Peak ) Qo = 3.30 5.60 cfs Water Spread Width T = 11.6 14.7 ft Water Depth at Flowline (outside of local depression) d = 4.8 5.5 inches Water Depth at Street Crown (or at TMAX)d CROWN = 0.0 0.0 inches Ratio of Gutter Flow to Design Flow Eo = 0.537 0.430 Discharge outside the Gutter Section W, carried in Section Tx Q x = 1.53 3.20 cfs Discharge within the Gutter Section W Qw = 1.77 2.41 cfs Discharge Behind the Curb Face QBACK = 0.00 0.00 cfs Street Flow Area As = 1.52 2.32 sq ft Street Flow Velocity Vs = 2.18 2.41 fps Water Depth for Design Condition dLOCAL = 6.8 7.5 inches Grate Analysis (Calculated) MINOR MAJOR Total Length of Inlet Grate Opening L = ft Ratio of Grate Flow to Design Flow Eo-GRATE = Under No-Clogging Condition MINOR MAJOR Minimum Velocity Where Grate Spash-Over Begins Vo = fps Interception Rate of Frontal Flow Rf = Interception Rate of Side Flow Rx = Interception Capacity Qi = cfs Under Clogging Condition MINOR MAJOR Clogging Coefficient for Multiple-unit Grate Inlet GrateCoef = Clogging Factor for Multiple-unit Grate Inlet GrateClog = Effective (unclogged) Length of Multiple-unit Grate Inlet Le = ft Minimum Velocity Where Grate Spash-Over Begins Vo = fps Interception Rate of Frontal Flow Rf = Interception Rate of Side Flow Rx = Actual Interception Capacity Qa = N/A N/A cfs Carry-Over Flow = Qo-Q a (to be applied to curb opening or next d/s inlet) Qb = N/A N/A cfs Curb or Slotted Inlet Opening Analysis (Calculated) MINOR MAJOR Equivalent Slope Se (based on grate carry-over) S e = 0.1095 0.0917 ft/ft Required Length LT to Have 100% Interception L T = 9.11 12.66 ft Under No-Clogging Condition MINOR MAJOR Effective Length of Curb Opening or Slotted Inlet (minimum of L, LT) L = 4.00 4.00 ft Interception Capacity Qi = 2.13 2.77 cfs Under Clogging Condition MINOR MAJOR Clogging Coefficient CurbCoef = 1.00 1.00 Clogging Factor for Multiple-unit Curb Opening or Slotted Inlet CurbClog = 0.10 0.10 Effective (Unclogged) Length Le = 3.60 3.60 ft Actual Interception Capacity Qa = 1.97 2.53 cfs Carry-Over Flow = Qb(GRATE)-Q a Qb = 1.33 3.07 cfs Summary MINOR MAJOR Project: Inlet ID: Gutter Geometry (Enter data in the blue cells) Maximum Allowable Width for Spread Behind Curb TBACK = 5.0 ft Side Slope Behind Curb (leave blank for no conveyance credit behind curb) SBACK = 0.0200 ft. vert. / ft. horiz Manning's Roughness Behind Curb nBACK = 0.0130 Height of Curb at Gutter Flow Line HCURB = 6.00 inches Distance from Curb Face to Street Crown TCROWN = 24.0 ft Gutter Depression a = 2.00 inches Gutter Width W = 2.00 ft Street Transverse Slope SX = 0.0200 ft. vert. / ft. horiz Street Longitudinal Slope - Enter 0 for sump condition SO = 0.0000 ft. vert. / ft. horiz Manning's Roughness for Street Section nSTREET = 0.0160 Minor Storm Major Storm Max. Allowable Water Spread for Minor & Major Storm TMAX = 14.0 18.0 ft Max. Allowable Depth at Gutter Flow Line for Minor & Major Storm dMAX = 6.00 6.00 inches Allow Flow Depth at Street Crown (leave blank for no) X = yes Maximum Gutter Capacity Based On Allowable Water Spread Minor Storm Major Storm Gutter Cross Slope (Eq. ST-8) SW = 0.1033 0.1033 ft/ft Water Depth without Gutter Depression (Eq. ST-2) y = 3.36 4.32 inches Water Depth with a Gutter Depression d = 5.36 6.32 inches Allowable Spread for Discharge outside the Gutter Section W (T - W) TX = 12.0 16.0 ft Gutter Flow to Design Flow Ratio by FHWA HEC-22 method (Eq. ST-7) EO = 0.451 0.350 Discharge outside the Gutter Section W, carried in Section TX Q X = 0.0 0.0 cfs Discharge within the Gutter Section W (QT - Q X)QW = 0.0 0.0 cfs Discharge Behind the Curb (e.g., sidewalk, driveways, & lawns) QBACK = 0.0 0.0 cfs Maximum Flow Based On Allowable Water Spread QT = SUMP SUMP cfs Flow Velocity Within the Gutter Section V = 0.0 0.0 fps V*d Product: Flow Velocity Times Gutter Flowline Depth V*d = 0.0 0.0 Maximum Gutter Capacity Based on Allowable Gutter Depth Minor Storm Major Storm Theoretical Water Spread TTH = 16.7 16.7 ft Theoretical Spread for Discharge outside the Gutter Section W (T - W) TX TH = 14.7 14.7 ft Gutter Flow to Design Flow Ratio by FHWA HEC-22 method (Eq. ST-7) EO = 0.378 0.378 Theoretical Discharge outside the Gutter Section W, carried in Section TX TH Q X TH = 0.0 0.0 cfs Actual Discharge outside the Gutter Section W, (limited by distance TCROWN)Q X = 0.0 0.0 cfs Discharge within the Gutter Section W (Qd - Q X)QW Project = Inlet ID = Design Information (Input) MINOR MAJOR Type of Inlet Type = Local Depression (additional to continuous gutter depression 'a' from 'Q-Allow') alocal = 2.00 2.00 inches Number of Unit Inlets (Grate or Curb Opening) No = 1 1 Grate Information MINOR MAJOR Length of a Unit Grate Lo (G) = N/A N/A feet Width of a Unit Grate Wo = N/A N/A feet Area Opening Ratio for a Grate (typical values 0.15-0.90) Aratio = N/A N/A Clogging Factor for a Single Grate (typical value 0.50 - 0.70) Cf (G) = N/A N/A Grate Weir Coefficient (typical value 3.00) Cw (G) = N/A N/A Grate Orifice Coefficient (typical value 0.67) Co (G) = N/A N/A Curb Opening Information MINOR MAJOR Warning 2 Length of a Unit Curb Opening Lo (C) = 4.00 4.00 feet Height of Vertical Curb Opening in Inches Hvert = 5.00 5.00 inches Height of Curb Orifice Throat in Inches Hthroat = 4.95 4.95 inches Angle of Throat (see USDCM Figure ST-5) Theta = 63.4 63.4 degrees Side Width for Depression Pan (typically the gutter width of 2 feet) Wp = 2.00 2.00 feet Clogging Factor for a Single Curb Opening (typical value 0.10) Cf (C) = 0.10 0.10 Curb Opening Weir Coefficient (typical value 2.30-3.00) Cw (C) = 2.30 2.30 Curb Opening Orifice Coefficient (typical value 0.67) Co (C) = 0.67 0.67 Resulting Gutter Flow Depth for Grate Inlet Capacity in a Sump MINOR MAJOR Clogging Coefficient for Multiple Units Coef = N/A N/A Clogging Factor for Multiple Units Clog = N/A N/A Grate as a Weir Flow Depth at Local Depression without Clogging (0 cfs grate, 1.64 cfs curb) dwi = N/A N/A inches This Row Used for Combination Inlets Only dcurb-un = N/A N/A inches Flow Depth at Local Depression with Clogging (0 cfs grate, 1.64 cfs curb) dwa = N/A N/A inches This Row Used for Combination Inlets Only dcurb-cl = N/A N/A inches Grate as an Orifice MINOR MAJOR Flow Depth at Local Depression without Clogging (0 cfs grate, 1.64 cfs curb) doi = N/A N/A inches Flow Depth at Local Depression with Clogging (0 cfs grate, 1.64 cfs curb) doa = N/A N/A inches Resulting Gutter Flow Depth Outside of Local Depression da-Grate = N/A N/A inches Resulting Gutter Flow Depth for Curb Opening Inlet Capacity in a Sump MINOR MAJOR Clogging Coefficient for Multiple Units Coef = 1.00 1.00 Clogging Factor for Multiple Units Clog = 0.10 0.10 Curb as a Weir, Grate as an Orifice MINOR MAJOR Flow Depth at Local Depression without Clogging (0 cfs grate, 1.64 cfs curb) dwi = 2.48 4.16 inches D APPENDIX D STORMWATER DETENTION POND ANALYSIS RATIONAL METHOD PEAK RUNOFF (City of Fort Collins, 100-Yr Storm - OLD rainfall) LOCATION: Harmony Cottages PROJECT NO: 1255-028-00 COMPUTATIONS BY: es DATE: 12/5/2015 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) 1 site 4.45 1.00 5.00 9.00 40.05 40.1 Allowable release under old reainfall conditions Q = C iA Q = peak discharge (cfs) C = runoff coefficient i = rainfall intensity (in/hr) from OLD City of Fort Collins IDF curve A = drainage area (acres) DETENTION VOLUME CALCULATIONS Rational Volumetric (FAA) Method 100-Year Event LOCATION: Harmony Cottages PROJECT NO: 1255-028-00 COMPUTATIONS BY: es DATE: 12/5/15 Equations: Area trib. to pond = 4.45 acre Developed flow = QD = CIA C (100) = 0.70 Vol. In = Vi = T C I A = T QD Developed C A = 3.1 acre - site only Vol. Out = Vo =K QPO T Release rate, QPO = 40.1 cfs storage = S = Vi - Vo K = 0.9 (from fig 2.1) Rainfall intensity from City of Fort Collins IDF Curve with updated (3.67") rainfall Storm Rainfall QD Vol. In Vol. Out Storage Storage Duration, T Intensity, I (cfs) Vi Vo S S (min) (in/hr) (ft3) (ft3) (ft3) (ac-ft) 5 9.95 31.0 9298 10814 -1515 -0.03 10 7.77 24.2 14515 21627 -7112 -0.16 20 5.62 17.5 21010 43254 -22244 -0.51 30 4.47 13.9 25054 64881 -39827 -0.91 40 3.74 11.6 27960 86508 -58548 -1.34 50 3.23 10.1 30220 108135 -77915 -1.79 60 2.86 8.9 32069 129762 -97693 -2.24 70 2.57 8.0 33634 151389 -117755 -2.70 80 2.34 7.3 34993 173016 -138023 -3.17 90 2.15 6.7 36195 194643 -158448 -3.64 100 1.99 6.2 37273 216270 -178997 -4.11 110 1.86 5.8 38251 237897 -199646 -4.58 120 1.75 5.4 39148 259524 -220376 -5.06 130 1.65 5.1 39977 281151 -241174 -5.54 140 1.56 4.9 40747 302778 -262031 -6.02 150 1.48 4.6 41467 324405 -282938 -6.50 160 1.41 4.4 42144 346032 -303888 -6.98 170 1.35 4.2 42783 367659 -324876 -7.46 180 1.29 4.0 43388 389286 -345898 -7.94 Required Storage Volume: -1515 ft3 -0.03 acre-ft E APPENDIX E WATER QUALITY AND LID INFORMATION Sheet 1 of 2 Designer: Company: Date: Project: Location: 1. Basin Storage Volume A) Effective Imperviousness of Tributary Area, Ia Ia = 50.0 % (100% if all paved and roofed areas upstream of rain garden) B) Tributary Area's Imperviousness Ratio (i = Ia/100) i = 0.500 C) Water Quality Capture Volume (WQCV) for a 12-hour Drain Time WQCV = 0.17 watershed inches (WQCV= 0.8 * (0.91* i3 - 1.19 * i2 + 0.78 * i) D) Contributing Watershed Area (including rain garden area) Area = 77,160 sq ft E) Water Quality Capture Volume (WQCV) Design Volume VWQCV = 1,061 cu ft Vol = (WQCV / 12) * Area F) For Watersheds Outside of the Denver Region, Depth of d6 = in Average Runoff Producing Storm G) For Watersheds Outside of the Denver Region, VWQCV OTHER = cu ft Water Quality Capture Volume (WQCV) Design Volume H) User Input of Water Quality Capture Volume (WQCV) Design Volume VWQCV USER = cu ft (Only if a different WQCV Design Volume is desired) 2. Basin Geometry A) WQCV Depth (12-inch maximum) DWQCV = 12 in B) Rain Garden Side Slopes (Z = 4 min., horiz. dist per unit vertical) Z = 4.00 ft / ft (Use "0" if rain garden has vertical walls) C) Mimimum Flat Surface Area AMin = 707 sq ft D) Actual Flat Surface Area AActual = 725 sq ft E) Area at Design Depth (Top Surface Area) ATop = 1400 sq ft F) Rain Garden Total Volume VT= 1,063 cu ft (VT= ((ATop + AActual) / 2) * Depth) 3. Growing Media Standard City of Fort Collins Spec 4. Underdrain System A) Are underdrains provided? B) Underdrain system orifice diameter for 12 hour drain time i) Distance From Lowest Elevation of the Storage y = ft Volume to the Center of the Orifice ii) Volume to Drain in 12 Hours Vol12 = N/A cu ft iii) Orifice Diameter, 3/8" Minimum DO = N/A in Harmony Cottages Basin A Design Procedure Form: Rain Garden (RG) sb Interwest Consulting Group January 19, 2016 Choose One Choose One 18" Rain Garden Growing Media Other (Explain): YES NO Rain Garden Basin A.xls, RG 1/19/2016, 6:48 PM Sheet 2 of 2 Designer: Company: Date: Project: Location: 5. Impermeable Geomembrane Liner and Geotextile Separator Fabric A) Is an impermeable liner provided due to proximity of structures or groundwater contamination? 6. Inlet / Outlet Control A) Inlet Control 7. Vegetation 8. Irrigation A) Will the rain garden be irrigated? Notes: Design Procedure Form: Rain Garden (RG) sb Interwest Consulting Group January 19, 2016 Harmony Cottages Basin A Choose One Choose One Choose One Sheet Flow- No Energy Dissipation Required Concentrated Flow- Energy Dissipation Provided Plantings Seed (Plan for frequent weed control) Sand Grown or Other High Infiltration Sod Choose One YES NO YES NO Rain Garden Basin A.xls, RG 1/19/2016, 6:48 PM Sheet 1 of 2 Designer: Company: Date: Project: Location: 1. Basin Storage Volume A) Effective Imperviousness of Tributary Area, Ia Ia = 50.0 % (100% if all paved and roofed areas upstream of rain garden) B) Tributary Area's Imperviousness Ratio (i = Ia/100) i = 0.500 C) Water Quality Capture Volume (WQCV) for a 12-hour Drain Time WQCV = 0.17 watershed inches (WQCV= 0.8 * (0.91* i3 - 1.19 * i2 + 0.78 * i) D) Contributing Watershed Area (including rain garden area) Area = 124,007 sq ft E) Water Quality Capture Volume (WQCV) Design Volume VWQCV = 1,705 cu ft Vol = (WQCV / 12) * Area F) For Watersheds Outside of the Denver Region, Depth of d6 = in Average Runoff Producing Storm G) For Watersheds Outside of the Denver Region, VWQCV OTHER = cu ft Water Quality Capture Volume (WQCV) Design Volume H) User Input of Water Quality Capture Volume (WQCV) Design Volume VWQCV USER = cu ft (Only if a different WQCV Design Volume is desired) 2. Basin Geometry A) WQCV Depth (12-inch maximum) DWQCV = 12 in B) Rain Garden Side Slopes (Z = 4 min., horiz. dist per unit vertical) Z = 4.00 ft / ft (Use "0" if rain garden has vertical walls) C) Mimimum Flat Surface Area AMin = 1137 sq ft D) Actual Flat Surface Area AActual = 1465 sq ft E) Area at Design Depth (Top Surface Area) ATop = 2567 sq ft F) Rain Garden Total Volume VT= 2,016 cu ft (VT= ((ATop + AActual) / 2) * Depth) 3. Growing Media Standard City of Fort Collins Spec 4. Underdrain System A) Are underdrains provided? B) Underdrain system orifice diameter for 12 hour drain time i) Distance From Lowest Elevation of the Storage y = ft Volume to the Center of the Orifice ii) Volume to Drain in 12 Hours Vol12 = N/A cu ft iii) Orifice Diameter, 3/8" Minimum DO = N/A in Harmony Cottages Basin B Design Procedure Form: Rain Garden (RG) sb Interwest Consulting Group January 19, 2016 Choose One Choose One 18" Rain Garden Growing Media Other (Explain): YES NO Rain Garden Basin B.xls, RG 1/19/2016, 6:49 PM Sheet 2 of 2 Designer: Company: Date: Project: Location: 5. Impermeable Geomembrane Liner and Geotextile Separator Fabric A) Is an impermeable liner provided due to proximity of structures or groundwater contamination? 6. Inlet / Outlet Control A) Inlet Control 7. Vegetation 8. Irrigation A) Will the rain garden be irrigated? Notes: Design Procedure Form: Rain Garden (RG) sb Interwest Consulting Group January 19, 2016 Harmony Cottages Basin B Choose One Choose One Choose One Sheet Flow- No Energy Dissipation Required Concentrated Flow- Energy Dissipation Provided Plantings Seed (Plan for frequent weed control) Sand Grown or Other High Infiltration Sod Choose One YES NO YES NO Rain Garden Basin B.xls, RG 1/19/2016, 6:49 PM New Impervious Area 110,940 sq. ft. Required Minimum Impervious Area to be Treated 83,205 sq. ft. Area Treated by Rain Garden A 35,370 sq. ft. Area Treated by Rain Garden B 66,650 sq. ft. Total Impervious Area Treated 102,020 sq. ft. Actual % On-Site Treated by LID 92 % Harmony Cottages LID Table 75% On-Site Treatment by LID Requirement PREPARED FOR PROJ. NO. DATE: SCALE (H): SCALE (V): CHECKED BY: DESIGNED BY: PROJECT NAME HARMONY COTTAGES LID EXHIBIT - RAIN GARDENS 04/13/16 1"=60' N/A RA RA 1255-028-00 1 HABITAT FOR HUMANITY 4001 S. TAFT HILL ROAD FORT COLLINS, CO 80525 PHONE: 970.223.4522 LEGEND IMPERVIOUS AREA TREATED BY RAIN GARDEN A (35,370 SF, 32% OF TOTAL IMP. AREA) IMPERVIOUS AREA TREATED BY RAIN GARDEN (66,650 SF, 60% OF TOTAL IMP. AREA) 0 SCALE: 1" = 60' 30 15 60 F APPENDIX F EXCERPTS FROM REFERENCE REPORTS G APPENDIX G SOIL REPORT AND FEMA INFORMATION FEMA's National Flood Hazard Layer (Official) http://fema.maps.arcgis.com/home/webmap/print.html[12/3/2015 11:16:14 AM] FEMA's National Flood Hazard Layer (Official) Data from Flood Insurance Rate Maps (FIRMs) where available digitally. Try http://bit.ly/1bPpUjq (Unofficial) if this map is down scott.mcafee@fema.dhs.gov | National Geospatial-Intelligence Agency (NGA); Delta State University; Esri Flow Depth at Local Depression with Clogging (0 cfs grate, 1.64 cfs curb) dwa = 2.57 4.31 inches Curb as an Orifice, Grate as an Orifice MINOR MAJOR Flow Depth at Local Depression without Clogging (0 cfs grate, 1.64 cfs curb) doi = 2.62 4.16 inches Flow Depth at Local Depression with Clogging (0 cfs grate, 1.64 cfs curb) doa = 2.72 4.61 inches Resulting Gutter Flow Depth Outside of Local Depression da-Curb = 0.72 2.61 inches Resultant Street Conditions MINOR MAJOR Total Inlet Length L = 4.0 4.0 feet Total Inlet Interception Capacity (Design Discharge from Q-Peak ) Qa = 1.6 3.6 cfs Resultant Gutter Flow Depth (based on sheet Q-Allow geometry) d = 0.72 2.61 inches Resultant Street Flow Spread (based on sheet Q-Allow geometry) T = 0.6 2.5 feet Resultant Flow Depth at Street Crown dCROWN = 0.00 0.00 inches Warning 2: Dimension entered is not a typical dimension for inlet type specified. CDOT Type R Curb Opening INLET IN A SUMP OR SAG LOCATION Harmony Cottages 4' Concrete Sidewalk Culvert in Sump H-Vert H-Curb W Lo (C) Lo (G) Wo W P 4' Curb Cut-Sump UD-Inlet_v2.14c.xls, Inlet In Sump 4/13/2016, 8:13 AM = 0.0 0.0 cfs Discharge Behind the Curb (e.g., sidewalk, driveways, & lawns) QBACK = 0.0 0.0 cfs Total Discharge for Major & Minor Storm Q = 0.0 0.0 cfs Flow Velocity Within the Gutter Section V = 0.0 0.0 fps V*d Product: Flow Velocity Times Gutter Flowline Depth V*d = 0.0 0.0 Slope-Based Depth Safety Reduction Factor for Major & Minor (d > 6") Storm R = SUMP SUMP Max Flow Based on Allow. Gutter Depth (Safety Factor Applied) Qd = SUMP SUMP cfs Resultant Flow Depth at Gutter Flowline (Safety Factor Applied) d= inches Resultant Flow Depth at Street Crown (Safety Factor Applied) dCROWN = inches Minor Storm Major Storm Max. Allowable Gutter Capacity Based on Minimum of QT or Q d Qallow = SUMP SUMP cfs MAJOR STORM max. allowable capacity OK - greater than flow given on sheet 'Q-Peak' ALLOWABLE CAPACITY FOR ONE-HALF OF STREET (Minor & Major Storm) Harmony Cottages 4' Concrete Sidewalk Culvert in Sump (Based on Regulated Criteria for Maximum Allowable Flow Depth and Spread) MINOR STORM max. allowable capacity OK - greater than flow given on sheet 'Q-Peak' H y d x S S w a Street Crown W T , T . Tx Q w Q x T CROWN . CURB S BACK T BACK . MAX 4' Curb Cut-Sump UD-Inlet_v2.14c.xls, Q-Allow 4/13/2016, 8:13 AM Total Inlet Interception Capacity Q = 1.97 2.53 cfs Total Inlet Carry-Over Flow (flow bypassing inlet) Qb = 1.34 3.07 cfs Capture Percentage = Qa/Q o = C% = 59.6 45.3 % Warning 3: CDOT Type R unit length should be a multiple of 5'. CDOT Type R Curb Opening INLET ON A CONTINUOUS GRADE Harmony Cottages On Grade 4' Concrete Sidewalk Culvert H-Vert H-Curb W Lo (C) Lo (G) Wo WP 4' Curb Cut-OnGrade UD-Inlet_v2.14c.xls, Inlet On Grade 4/13/2016, 8:12 AM = 2.9 2.9 cfs Discharge Behind the Curb (e.g., sidewalk, driveways, & lawns) QBACK = 0.0 0.0 cfs Total Discharge for Major & Minor Storm Q = 7.6 7.6 cfs Flow Velocity Within the Gutter Section V = 3.6 3.6 fps V*d Product: Flow Velocity Times Gutter Flowline Depth V*d = 1.8 1.8 Slope-Based Depth Safety Reduction Factor for Major & Minor (d > 6") Storm R = 1.00 1.00 Max Flow Based on Allow. Gutter Depth (Safety Factor Applied) Qd = 7.6 7.6 cfs Resultant Flow Depth at Gutter Flowline (Safety Factor Applied) d= 6.00 6.00 inches Resultant Flow Depth at Street Crown (Safety Factor Applied) dCROWN = 0.00 0.00 inches Minor Storm Major Storm Max. Allowable Gutter Capacity Based on Minimum of QT or Q d Qallow = 5.0 7.6 cfs MAJOR STORM max. allowable capacity OK - greater than flow given on sheet 'Q-Peak' ALLOWABLE CAPACITY FOR ONE-HALF OF STREET (Minor & Major Storm) Harmony Cottages On Grade 4' Concrete Sidewalk Culvert (Based on Regulated Criteria for Maximum Allowable Flow Depth and Spread) MINOR STORM max. allowable capacity OK - greater than flow given on sheet 'Q-Peak' H y d x S S w a Street Crown W T , T . Tx Q w Q x T CROWN . CURB S BACK T BACK . MAX 4' Curb Cut-OnGrade UD-Inlet_v2.14c.xls, Q-Allow 4/13/2016, 8:11 AM