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HomeMy WebLinkAboutTHE GREEN SOLUTION - PDP/FDP - FDP150045 - SUBMITTAL DOCUMENTS - ROUND 2 - DRAINAGE REPORTFINAL DRAINAGE REPORT FOR THE GREEN SOLUTION 810 NORTH COLLEGE AVENUE FORT COLLINS, COLORADO LARIMER COUNTY February 1, 2016 Prepared for: The Green Solution 700 17 th Street, Suite 1610 Denver, CO 80202 Contact: Kyle Speidell 720.399.6840 Prepared By: Manhard Consulting, Ltd. 8008 East Arapahoe Ct., Suite 110 Centennial, Colorado 80112 Contact: Daniel Madruga (303) 531-3400 TGSFCCO01 i Engineer’s Statement: This Drainage Report for The Green Solution was prepared by me, or under my direct supervision, in accordance with the provisions of the City of Fort Collins Stormwater Criteria Manual and was designed to comply with the provisions thereof. I understand that the City of Fort Collins does not and will not, assume liability for drainage facilities designed by others. ___________________________________ Daniel J. Madruga, PE Registered Professional Engineer State of Colorado No. 36834 ii Table of Contents INTRODUCTION 1 Location ................................................................................................................................. 1 Site Description ..................................................................................................................... 1 Proposed Development ......................................................................................................... 1 DRAINAGE BASINS AND SUB-BASINS 1 Overall Basin Description ...................................................................................................... 1 Drainage Patterns Through Property .................................................................................... 2 DESIGN CRITERIA 2 Hydrologic Criteria ................................................................................................................. 2 Hydraulic Criteria ................................................................. Error! Bookmark not defined.2 DRAINAGE PLAN 3 General Concept ................................................................................................................... 3 CONCLUSION 4 Compliance with Standards .................................................................................................. 4 Summary of Concept ............................................................................................................. 4 REFERENCES 5 Appendix A FIRM Map Soils Maps Drainage Maps Appendix B Hydrologic Calculations Appendix C Filterra Design Information Hydraulic Calculations iii Vicinity Map 1 INTRODUCTION This report presents The Green Solution drainage report and drainage system design. The design and analysis of this site has been performed in accordance with the Urban Drainage and Flood Control District (UDFCD) “Urban Storm Drainage Criteria Manual” along with City of Fort Collins Amendments. Drawings, tables, and design calculations are included in the appendices of this report. Location The proposed development is part of Section 1, Township 7 North, Range 69 West of the 6th Principal Meridian, City of Fort Collins, Larimer County, State of Colorado. More specifically it is located at 810 N College Avenue. Adjacent developments include an existing bowling alley to the north, an existing liquor store to the east, and an existing auto sales business to the south. Site Description The site is approximately 0.30 acres and the existing condition consists of a medical marijuana store and associated parking area. The existing parking area located between the building and N. College Avenue will be removed and replaced primarily with landscaping. A portion of the existing building and the asphalt to the east of the existing building will be demolished for the construction of the building addition. The topography for the site generally slopes from northwest to southeast at approximately 1.5%. Based on the USDA Web Soil Survey, the soils within the site are Nunn clay loam which falls into Hydrologic Soils Group Type C. There is very little existing vegetation on site. The site is located within the FEMA 100-year floodplain, Zone AE, as indicated on the Flood Insurance Rate Map, Panel Number 08069C0977G, revised June 17, 2008. Proposed Development The proposed project will expand an existing medical marijuana facility for use as a retail marijuana store. The current building, which has previously been expanded multiple times, is approximately 2,300 square feet. Although the project includes an approximate 2,500 sf building addition, the impervious area for this project will decrease by approximately 3400 sf. It is intended that the floor of the addition match the elevation of the existing, which is 4968.9. The Base Flood Elevation (BFE) at the upstream side of the building is 4969.77. The total structure is to be dry-floodproofed, with flood resistant materials up to the Regulatory Flood Protection Elevation (RFPE), which is 4971.77, and floodproof doorways at the exterior walls of the building. DRAINAGE BASINS AND SUB-BASINS Overall Basin Description Based on the Drainage Basin Master Plan, the site is located within the Dry Creek Drainage Basin, which is tributary to the Poudre River. More specifically, the site is located within Basin 517 of the Northeast College Corridor Outfall (NECCO). The land use in the Dry Creek Drainage Basin is primarily rangeland and irrigated hay meadows and pastures in the upper and middle portions of the basin. The majority of the lower basin, where the site is located, is developed and includes, commercial, industrial, and residential uses. 2 Drainage Patterns Through Property The existing site drains from west to east toward a natural low point in the southeast corner of the site and continues to flow overland off-site to the east and eventually to the Josh Ames Ditch to the south. The existing flows are currently undetained and without water quality control on-site. DESIGN CRITERIA Hydrologic Criteria The Urban Drainage and Flood Control District (UDFCD) “Urban Storm Drainage Criteria Manual” along with City of Fort Collins Amendments were used for the storm drainage system design. Since the site falls within basin 517 of the Northeast College Corridor Outfall (NECCO), quantity and quality detention will be handled by a regional facility. The runoff rates for the existing conditions and the proposed conditions were calculated as follows: Design Rainfall: Rainfall data from The City of Fort Collins Amendments to the Urban Storm Drainage Criteria Manual was used to determine peak runoff rates for the 2-year (minor) and 100- year (major) storms. Runoff Calculation: Peak storm runoff is determined using the rational formula, Q = CIA: Q = storm runoff in CFS; C = runoff coefficient based on surface impermeability; I = rainfall intensity in inches per hour; and A = drainage basin area in acres. Runoff Coefficients (Table RO-11) and appropriate adjustment factors (Table RO-12) were used to develop runoff coefficients for the minor and major storm events. The runoff coefficients are weighted to more accurately reflect the runoff characteristics of the site. Time of Concentration is determined using the criteria in Section 2.4 of the UDFCD Criteria Manual. Per the direction of the City of Fort Collins, the time of concentration was determined for both the minor and major storm events by using the respective runoff coefficients as described above. Rainfall intensities were determined using Figures RA-7 and RA-8 of the City of Fort Collins Amendments to the UDFCD Criteria Manual along with the equation (shown below) presented in the UDFCD Criteria Manual. One-hour storm depths for the 2-year and 100-year storms are 0.82 inches and 2.86 inches respectively. Intensity results are shown in tabular form in Appendix B, based on the Equation 1. 𝐼 = 28.5𝑃1 (10+𝑡𝑐 ).786 Equation 1 The rational method (Q = CIA), as shown in the Urban Storm Drainage Criteria Manual, was used to calculate total runoff (Q) for the 2-year and 100-year storm events. Results are shown in the Appendix B. 3 DRAINAGE PLAN General Concept Stormwater detention and water quality have been accounted for this site within the Northeast College Corridor Outfall (NECCO). A Low Impact Development (LID) system has been provided to meet the City of Fort Collins requirements. Over 75% of the new impervious area, will be directed to a Filterra biofitraltion system located on the southeast corner of the property. Specific Details The proposed development has been divided into three major basins: Basin A, Basin B, and the OS Basin. A drainage map, presenting the drainage basin delineations as well as existing and proposed drainage facilities, can be found in Appendix A of this report. The following text generally describes basin conveyance to design points. Hydrologic calculations for each sub-basin are presented in the rational method SF-3 forms in Appendix B of this report. Sub-basin A-1, 0.019 acres, is located in the northwest corner of the property and consists of a portion of the proposed sidewalk and isolated parking space to the west. This flow will be collected by a curb inlet at the northwest corner of the parking area and conveyed to the existing inlet in N. College Avenue. Sub-basin A-2, 0.027 acres, consists of the western portion of the parking area. This flow will be collected by a curb inlet at the northwest corner of the main parking area and conveyed to the existing inlet in N. College Avenue. Sub-basin B-1, 0.037 acres, consists of the eastern portion of the parking area. This flow will be directed through a storm chase in the southeastern corner of the parking area. This flow will ultimately be directed to a Filterra Biofiltration system in the southeast corner of the property. Sub-basin B-2, 0.015 acres, consists of the sidewalk along the eastern side of the building and trash enclosure area. This flow will be directed through an opening in the trash enclosure wall to a Filterra Biofiltration system in the southeast corner of the property. Sub-basin B-3, 0.110 acres, consists of the roof of the building and will be discharged at grade through four downspouts on the southern side of the building. This flow will be directed to a Filterra Biofiltration system in the southeast corner of the property. Sub-basin B-4, 0.031 acres, consists of the landscaped area to the south of the building. This flow will be directed to a Filterra Biofiltration system in the southeast corner of the property. Sub-basin OS-1, 0.058 acres, consists of the landscaped area and sidewalk in the front of the building. This flows to an area drain in the southwest portion of the site conveyed to the existing inlet in N. College Avenue. Sub-basin OS-2, 0.01 acres, consists of proposed asphalt pavement area on the west edge of the property. This area will flow away from the site, matching existing drainage patterns. The Filterra system is similar to bioretention in its function and application, but has been optimized for high volume/flow treatment and high pollutant removal. Stormwater runoff from Sub-basins B-1 through B-4 enters the system through a curb inlet and flows through a specially designed filter media mixture contained inside the inlet box and to an underdrain system, where the treated water will be discharged to the existing stormwater system in N. College Ave. Once the Filterra system 4 has reached its capacity, the additional runoff will bypass the Filterra system and discharge overland to the west along the historical drainage path for this site. Additional information can be found in Appendix C. Storm Sewer The storm sewer capacities and the capacity of the opening on the south side of the trash enclosure wall were determined using FlowMaster. The Nyloplast inlet grates have been sized to accept the anticipated flows from the 100-year storm event. Refer to Appendix C for Hydraulic calculations. Maintenance and Inspection The maintenance of the Filterra system will be completed by the supplier within the first year of operation. Beyond this period, the Filterra system should be inspected a minimum of twice annually for standing water, damage to the box structure or grate, and bypass. The mulch should be removed and replaced a minimum of once a year. At all times, the system should be kept clear of trash and other debris. CONCLUSION Compliance with Standards The drainage system and LID system for the Green Solution site were designed to meet the City of Fort Collins’ drainage criteria. The site is located within a F.E.M.A. mapped floodplain, however the project does not require a map revision. The existing building and proposed addition will be floodproofed in accordance with F.E.M.A. and the City of Fort Collins standards. Summary of Concept The drainage system for the Green Solution site was designed to allow storm water to be safely conveyed through and away from the site without negatively impacting downstream or upstream properties beyond that imposed by the historic condition. All drainage facilities proposed with this development are private facilities and will be maintained by the owner. 5 REFERENCES 1. City of Fort Collins Amendments to the Urban Drainage and Flood Control District Criteria Manual, December, 2012. 2. Urban Drainage and Flood Control District, Denver, Colorado, Urban Storm Drainage Criteria Manual, Volumes 1, 2 & 3, June 2001. Appendix A FIRM Map Soils Map Drainage Maps Soil Map—Larimer County Area, Colorado Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 12/4/2015 Page 1 of 3 4494130 4494137 4494144 4494151 4494158 4494165 4494172 4494130 4494137 4494144 4494151 4494158 4494165 4494172 493518 493525 493532 493539 493546 493553 493560 493567 493574 493581 493588 493518 493525 493532 493539 493546 493553 493560 493567 493574 493581 493588 40° 35' 54'' N 105° 4' 35'' W 40° 35' 54'' N 105° 4' 32'' W 40° 35' 52'' N 105° 4' 35'' W 40° 35' 52'' N 105° 4' 32'' W N Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 13N WGS84 0 15 30 60 90 Feet 0 4 9 18 27 Meters Map Scale: 1:328 if printed on A landscape (11" x 8.5") sheet. MAP LEGEND MAP INFORMATION Area of Interest (AOI) Area of Interest (AOI) Soils Soil Map Unit Polygons Soil Map Unit Lines Soil Map Unit Points Special Point Features Blowout Borrow Pit Clay Spot Closed Depression Gravel Pit Gravelly Spot Landfill Lava Flow Marsh or swamp Mine or Quarry Miscellaneous Water Perennial Water Rock Outcrop Saline Spot Sandy Spot Severely Eroded Spot Sinkhole Slide or Slip Sodic Spot Spoil Area Stony Spot Very Stony Spot Wet Spot Other Special Line Features Water Features Streams and Canals Transportation Rails Interstate Highways US Routes Major Roads Local Roads Background Aerial Photography The soil surveys that comprise your AOI were mapped at 1:24,000. Warning: Soil Map may not be valid at this scale. Enlargement of maps beyond the scale of mapping can cause misunderstanding of the detail of mapping and accuracy of soil line placement. The maps do not show the small areas of contrasting soils that could have been shown at a more detailed scale. Please rely on the bar scale on each map sheet for map measurements. Source of Map: Natural Resources Conservation Service Web Soil Survey URL: http://websoilsurvey.nrcs.usda.gov Coordinate System: Web Mercator (EPSG:3857) Maps from the Web Soil Survey are based on the Web Mercator projection, which preserves direction and shape but distorts distance and area. A projection that preserves area, such as the Albers equal-area conic projection, should be used if more accurate calculations of distance or area are required. This product is generated from the USDA-NRCS certified data as of Map Unit Legend Larimer County Area, Colorado (CO644) Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI 73 Nunn clay loam, 0 to 1 percent slopes 0.4 100.0% Totals for Area of Interest 0.4 100.0% Soil Map—Larimer County Area, Colorado Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 12/4/2015 Page 3 of 3 Hydrologic Soil Group—Larimer County Area, Colorado Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 12/4/2015 Page 1 of 4 4494130 4494137 4494144 4494151 4494158 4494165 4494172 4494130 4494137 4494144 4494151 4494158 4494165 4494172 493518 493525 493532 493539 493546 493553 493560 493567 493574 493581 493588 493518 493525 493532 493539 493546 493553 493560 493567 493574 493581 493588 40° 35' 54'' N 105° 4' 35'' W 40° 35' 54'' N 105° 4' 32'' W 40° 35' 52'' N 105° 4' 35'' W 40° 35' 52'' N 105° 4' 32'' W N Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 13N WGS84 0 15 30 60 90 Feet 0 4 9 18 27 Meters Map Scale: 1:328 if printed on A landscape (11" x 8.5") sheet. MAP LEGEND MAP INFORMATION Area of Interest (AOI) Area of Interest (AOI) Soils Soil Rating Polygons A A/D B B/D C C/D D Not rated or not available Soil Rating Lines A A/D B B/D C C/D D Not rated or not available Soil Rating Points A A/D B B/D C C/D D Not rated or not available Water Features Streams and Canals Transportation Rails Interstate Highways US Routes Major Roads Local Roads Background Aerial Photography The soil surveys that comprise your AOI were mapped at 1:24,000. Warning: Soil Map may not be valid at this scale. Enlargement of maps beyond the scale of mapping can cause misunderstanding of the detail of mapping and accuracy of soil line placement. The maps do not show the small areas of contrasting soils that could have been shown at a more detailed scale. Please rely on the bar scale on each map sheet for map measurements. Source of Map: Natural Resources Conservation Service Web Soil Survey URL: http://websoilsurvey.nrcs.usda.gov Coordinate System: Web Mercator (EPSG:3857) Maps from the Web Soil Survey are based on the Web Mercator projection, which preserves direction and shape but distorts distance and area. A projection that preserves area, such as the Albers equal-area conic projection, should be used if more accurate calculations of distance or area are required. This product is generated from the USDA-NRCS certified data as of the version date(s) listed below. Soil Survey Area: Larimer County Area, Colorado Hydrologic Soil Group Hydrologic Soil Group— Summary by Map Unit — Larimer County Area, Colorado (CO644) Map unit symbol Map unit name Rating Acres in AOI Percent of AOI 73 Nunn clay loam, 0 to 1 percent slopes C 0.4 100.0% Totals for Area of Interest 0.4 100.0% Description Hydrologic soil groups are based on estimates of runoff potential. Soils are assigned to one of four groups according to the rate of water infiltration when the soils are not protected by vegetation, are thoroughly wet, and receive precipitation from long-duration storms. The soils in the United States are assigned to four groups (A, B, C, and D) and three dual classes (A/D, B/D, and C/D). The groups are defined as follows: Group A. Soils having a high infiltration rate (low runoff potential) when thoroughly wet. These consist mainly of deep, well drained to excessively drained sands or gravelly sands. These soils have a high rate of water transmission. Group B. Soils having a moderate infiltration rate when thoroughly wet. These consist chiefly of moderately deep or deep, moderately well drained or well drained soils that have moderately fine texture to moderately coarse texture. These soils have a moderate rate of water transmission. Group C. Soils having a slow infiltration rate when thoroughly wet. These consist chiefly of soils having a layer that impedes the downward movement of water or soils of moderately fine texture or fine texture. These soils have a slow rate of water transmission. Group D. Soils having a very slow infiltration rate (high runoff potential) when thoroughly wet. These consist chiefly of clays that have a high shrink-swell potential, soils that have a high water table, soils that have a claypan or clay layer at or near the surface, and soils that are shallow over nearly impervious material. These soils have a very slow rate of water transmission. If a soil is assigned to a dual hydrologic group (A/D, B/D, or C/D), the first letter is for drained areas and the second is for undrained areas. Only the soils that in their natural condition are in group D are assigned to dual classes. Rating Options Aggregation Method: Dominant Condition Component Percent Cutoff: None Specified Hydrologic Soil Group—Larimer County Area, Colorado Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 12/4/2015 Page 3 of 4 Tie-break Rule: Higher Hydrologic Soil Group—Larimer County Area, Colorado Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 12/4/2015 Page 4 of 4 Appendix B Hydrologic Calculations RUNOFF COEFFICIENTS AND IMPERVIOUSNESS The Green Solution - Fort Collins 2/1/2016 Land Use Impervious 2-yr 5-yr 100-yr Paving 0.95 0.95 1.00 100% Sidewalk 0.95 0.95 1.00 100% Roofs 0.95 0.95 1.00 100% Lawns 0.1 0.10 0.13 0% Soil Type = C Basin No Total Area Paved Area Sidewalk Area Roofed Area Lawn Area Composite Imperviousness (AC) (AC) (AC) (AC) (AC) 2 Year 5 Year 100 Year (%) E-1 0.31 0.22 0.02 0.06 0.01 0.93 0.93 0.97 97.1% ONSITE TOTAL 0.31 0.22 0.02 0.06 0.01 0.93 0.93 0.97 97.1% Runoff Coeff. Composite Runoff Coefficient The Green Solution - Fort Collins TIME OF CONCENTRATION JOB NO: DATE: 2/1/2016 PROJECT: TGSFCCO01 CALCULATED BY: JAR DESIGN STORM: 2 YEAR INITIAL/OVERLAND TRAVEL TIME FINAL TIME (ti) (tt) tc TRIBUTARY AREA C LENGTH SLOPE ti LENGTH SLOPE Conveyance VEL tt COMP. TOTAL (L/180)+10 BASINS Ac Ft % Min. Ft. % Coefficient fps Min. tc LENGTH Min. Min. (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (13) (14) E-1 0.31 0.93 60 1.10 2.36 160 0.90 20 1.90 1.41 3.77 220 11.22 5.00 NOTES: Ti = [1.8 x (1.1 - C 5) x L 0.5 ] / (S 0.33 ) *S IN %* V = (Cv) x (S w 0.5 ) Tt = L / (60 x V) TC Check = 10 + L/180 (Urbanized Basins Only) Tc Min = 10 Minutes (Per XXX) tc CHECK (URBANIZED BASINS) The Green Solution - Fort Collins TIME OF CONCENTRATION JOB NO: DATE: 2/1/2016 PROJECT: TGSFCCO01 CALCULATED BY: JAR DESIGN STORM: 100 YEAR INITIAL/OVERLAND TRAVEL TIME FINAL TIME (ti) (tt) tc TRIBUTARY AREA C100 LENGTH SLOPE ti LENGTH SLOPE Conveyance VEL tt COMP. TOTAL (L/180)+10 BASINS Ac Ft % Min. Ft. % Coefficient fps Min. tc LENGTH Min. Min. (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (13) (14) E-1 0.31 0.93 60 1.10 2.36 160 0.90 20 1.90 1.41 3.77 220 11.22 5.00 NOTES: Ti = [1.8 x (1.1 - C 5) x L 0.5 ] / (S 0.33 ) *S IN %* V = (Cv) x (S w 0.5 ) Tt = L / (60 x V) TC Check = 10 + L/180 (Urbanized Basins Only) Tc Min = 10 Minutes (Per XXX) tc CHECK (URBANIZED BASINS) DATE: 2/1/2016 JOB NO: CALCULATED BY: JAR PROJECT: TGSFCCO01 2 Year, 1 Hour Point Rainfall Depth = 0.82 in DIRECT RUNOFF TOTAL RUNOFF CARRYOVER Basin Design Area C2 C x A Tc Intensity Qd = CIA C x A Tc Intensity Qd = CIA C x A Tc Intensity Qd = CIA To Design Point (acres) (min) (in/hr) (cfs) (min) (in/hr) (cfs) (min) (in/hr) (cfs) Point E-1 1 0.31 0.93 0.29 5.00 2.78 0.79 TOTAL 0.79 NOTES: I = (28.5 x P1) / (10 + T c) 0.786 The Green Solution - Fort Collins 2-YEAR RUNOFF CALCULATIONS DATE: 2/1/2016 JOB NO: CALCULATED BY: JAR PROJECT: TGSFCCO01 100 Year, 1 Hour Point Rainfall Depth = 2.86 in DIRECT RUNOFF TOTAL RUNOFF CARRYOVER Basin Design Area C100 C x A Tc Intensity Qd = CIA C x A Tc Intensity Qd = CIA C x A Tc Intensity Qd = CIA To Design Point (acres) (min) (in/hr) (cfs) (min) (in/hr) (cfs) (min) (in/hr) (cfs) Point E-1 1 0.31 0.97 0.30 5.00 9.70 2.92 TOTAL 2.92 NOTES: I = (28.5 x P1) / (10 + T c) 0.786 The Green Solution - Fort Collins 100-YEAR RUNOFF CALCULATIONS RUNOFF COEFFICIENTS AND IMPERVIOUSNESS The Green Solution - Fort Collins 1/25/2016 Land Use Impervious 2-yr 5-yr 100-yr Pavement 0.95 0.95 1.00 100% Roof 0.95 0.95 1.00 100% Landscape 0.10 0.10 0.13 0% Soil Type = C Basin No Total Area Paved Area Roofed Area Lawn Area Composite Imperviousness (AC) (AC) (AC) (AC) 2 Year 5 Year 100 Year (%) A-1 0.019 0.014 0.000 0.005 0.74 0.74 0.78 75.3% A-2 0.027 0.022 0.000 0.005 0.78 0.78 0.83 80.3% SUBTOTAL 0.045 0.036 0.000 0.010 0.77 0.77 0.81 78.3% B-1 0.037 0.031 0.000 0.006 0.81 0.81 0.86 83.4% B-2 0.015 0.013 0.000 0.002 0.86 0.86 0.90 89.0% B-3 0.110 0.000 0.110 0.000 0.95 0.95 1.00 100.0% B-4 0.031 0.000 0.000 0.031 0.10 0.10 0.13 0.0% SUBTOTAL 0.193 0.044 0.110 0.039 0.78 0.78 0.82 79.9% OS-1 0.058 0.008 0.000 0.049 0.22 0.22 0.25 14.5% OS-2 0.011 0.011 0.000 0.000 0.95 0.95 1.00 100.0% SUBTOTAL 0.069 0.020 0.000 0.049 0.34 0.34 0.38 28.6% TOTAL 0.31 0.10 0.11 0.10 0.68 0.68 0.72 68.1% Runoff Coeff. Composite Runoff Coefficient The Green Solution - Fort Collins TIME OF CONCENTRATION JOB NO: DATE: 1/25/2016 PROJECT: TGSFCCO01 CALCULATED BY: JAR DESIGN STORM: 2 YEAR INITIAL/OVERLAND TRAVEL TIME FINAL TIME (ti) (tt) tc TRIBUTARY AREA C LENGTH SLOPE ti LENGTH SLOPE Conveyance VEL tt COMP. TOTAL (L/180)+10 BASINS Ac Ft % Min. Ft. % Coefficient fps Min. tc LENGTH Min. Min. (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (13) (14) A-1 0.02 0.74 18 2.80 1.94 47 1.50 20 2.45 0.32 2.26 65 10.36 5.00 A-2 0.03 0.78 11 2.00 1.51 44 1.00 20 2.00 0.37 1.87 55 10.31 5.00 B-1 0.04 0.81 11 2.00 1.38 56 2.50 20 3.16 0.29 1.67 67 10.37 5.00 B-2 0.01 0.86 6 1.20 1.01 63 1.00 20 2.00 0.53 1.54 69 10.38 5.00 B-3 0.11 0.95 25 0.50 1.70 16 0.50 20 1.41 0.19 1.89 41 10.23 5.00 B-4 0.03 0.10 40 2.00 9.06 83 2.00 7 0.99 1.40 10.45 123 10.68 10.45 OS-1 0.06 0.22 17 2.00 5.18 45 2.00 7 0.99 0.76 5.93 62 10.34 5.00 OS-2 0.01 0.95 12 3.50 0.62 0.00 0.00 0.62 12 10.07 5.00 NOTES: Ti = [1.8 x (1.1 - C 5) x L 0.5 ] / (S 0.33 ) *S IN %* V = (Cv) x (S w 0.5 ) Tt = L / (60 x V) TC Check = 10 + L/180 (Urbanized Basins Only) Tc Min = 5 Minutes (Per XXX) tc CHECK (URBANIZED BASINS) The Green Solution - Fort Collins TIME OF CONCENTRATION JOB NO: DATE: 1/25/2016 PROJECT: TGSFCCO01 CALCULATED BY: JAR DESIGN STORM: 100 YEAR INITIAL/OVERLAND TRAVEL TIME FINAL TIME (ti) (tt) tc TRIBUTARY AREA C5 LENGTH SLOPE ti LENGTH SLOPE Conveyance VEL tt COMP. TOTAL (L/180)+10 BASINS Ac Ft % Min. Ft. % Coefficient fps Min. tc LENGTH Min. Min. (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (13) (14) A-1 0.02 0.78 18 2.80 1.70 47 1.50 20 2.45 0.32 2.02 65 10.36 5.00 A-2 0.03 0.83 11 2.00 1.29 44 1.00 20 2.00 0.37 1.66 55 10.31 5.00 B-1 0.04 0.86 11 2.00 1.16 56 2.50 20 3.16 0.29 1.46 67 10.37 5.00 B-2 0.01 0.90 6 1.20 0.82 63 1.00 20 2.00 0.53 1.34 69 10.38 5.00 B-3 0.11 1.00 25 0.50 1.13 16 0.50 20 1.41 0.19 1.32 41 10.23 5.00 B-4 0.03 0.13 40 2.00 8.83 83 2.00 7 0.99 1.40 10.23 123 10.68 10.23 OS-1 0.06 0.25 17 2.00 5.01 45 2.00 7 0.99 0.76 5.76 62 10.34 5.00 OS-2 0.01 1.00 0.00 46 0.50 20 1.41 0.54 0.54 46 10.26 5.00 NOTES: Ti = [1.8 x (1.1 - C 5) x L 0.5 ] / (S 0.33 ) *S IN %* V = (Cv) x (S w 0.5 ) Tt = L / (60 x V) TC Check = 10 + L/180 (Urbanized Basins Only) Tc Min = 5 Minutes (Per XXX) tc CHECK (URBANIZED BASINS) DATE: 1/25/2016 JOB NO: CALCULATED BY: JAR PROJECT: TGSFCCO01 2 Year, 1 Hour Point Rainfall Depth = 0.82 in DIRECT RUNOFF TOTAL RUNOFF CARRYOVER Basin Design Area C2 C x A Tc Intensity Qd = CIA C x A Tc Intensity Qd = CIA C x A Tc Intensity Qd = CIA To Design Point (acres) (min) (in/hr) (cfs) (min) (in/hr) (cfs) (min) (in/hr) (cfs) Point A-1 1 0.02 0.74 0.01 5.00 2.78 0.04 A-2 2 0.03 0.78 0.02 5.00 2.78 0.06 A1+A2 0.10 B-1 3 0.04 0.81 0.03 5.00 2.78 0.08 B-2 4 0.01 0.86 0.01 5.00 2.78 0.03 B1+B2 0.12 B-3 5 0.11 0.95 0.10 5.00 2.78 0.29 B-4 6 0.03 0.10 0.00 10.45 2.18 0.01 B3+B4 0.30 B1+B2+B3+B4 0.42 OS-1 7 0.06 0.22 0.01 5.00 2.78 0.04 OS-2 8 0.01 0.95 0.01 5.00 2.78 0.03 TOTAL 0.58 NOTES: I = (28.5 x P1) / (10 + T c) 0.786 The Green Solution - Fort Collins 2-YEAR RUNOFF CALCULATIONS DATE: 1/25/2016 JOB NO: CALCULATED BY: JAR PROJECT: TGSFCCO01 100 Year, 1 Hour Point Rainfall Depth = 2.86 in DIRECT RUNOFF TOTAL RUNOFF CARRYOVER Basin Design Area C100 C x A Tc Intensity Qd = CIA C x A Tc Intensity Qd = CIA C x A Tc Intensity Qd = CIA To Design Point (acres) (min) (in/hr) (cfs) (min) (in/hr) (cfs) (min) (in/hr) (cfs) Point A-1 1 0.02 0.78 0.01 5.00 9.70 0.14 A-2 2 0.03 0.83 0.02 5.00 9.70 0.22 A1+A2 0.36 B-1 3 0.04 0.86 0.03 5.00 9.70 0.31 B-2 4 0.01 0.90 0.01 5.00 9.70 0.13 B1+B2 0.44 B-3 5 0.11 1.00 0.11 5.00 9.70 1.07 B-4 6 0.03 0.13 0.00 10.23 7.67 0.03 B3+B4 1.10 B1+B2+B3+B4 1.54 OS-1 7 0.06 0.25 0.01 5.00 9.70 0.14 OS-2 8 0.01 1.00 0.01 5.00 9.70 0.11 TOTAL 2.15 NOTES: I = (28.5 x P1) / (10 + T c) 0.786 The Green Solution - Fort Collins 100-YEAR RUNOFF CALCULATIONS Appendix C Filterra Design Information Hydraulic Calculations Project Description Solve For Headwater Elevation Input Data Discharge 0.44 ft³/s Centroid Elevation 0.33 ft Tailwater Elevation 0.00 ft Discharge Coefficient 0.60 Opening Width 1.33 ft Opening Height 0.67 ft Results Headwater Elevation 0.34 ft Headwater Height Above Centroid 0.01 ft Tailwater Height Above Centroid -0.33 ft Flow Area 0.89 ft² Velocity 0.49 ft/s Trash Enclosure Wall Opening 2/2/2016 2:02:40 PM Bentley Systems, Inc. Haestad Methods Solution Bentley Center FlowMaster V8i (SELECTseries 1) [08.11.01.03] 27 Siemons Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 Page 1 of 1 Filterra Sizing - Denver Sizing Basis: Design Parameters: Design Storm = 0.60" Rainfall (WQ Event per Urban Drainage) Filterra Media Flow Rate = 140"/hr Site Drainage Area = 0.585 Percent Impervious = 100% (CN = 98) Time of Concentration = 6 min Allowable Ponding in Filterra = 9" Filterra Model Size Analyzed = 13' x 7' (Treats 0.295 cfs at 140"/hr) Design Summary: Table 1. Filterra Sizing based on the Denver Design Storm. System Size Treatment Flow Rate at 140"/hr Maximum Impervious Drainage Area When Fully Ponded (CN = 98) Outlet Pipe Size (ft) (cfs) (ac) 4x4 0.05 0.102 4" PVC 4x6 / 6x4 0.08 0.154 4" PVC 4x8 / 8x4 0.10 0.205 4" PVC 6x6 0.12 0.231 4" PVC 6x8 / 8x6 / 4x12 / 12x4 0.16 0.308 4" PVC 6x10 / 10x6 0.19 0.386 6" PVC 6x12 / 12x6 0.23 0.463 6" PVC 7x13 / 13x7 0.29 0.585 6" PVC Notes: 3. Dimensions shown are internal. 4. Contact Contech for site specific sizing. The sizing for the Filterra system under the Denver regulations is based on designing the system to provide treatment of the 0.60" design storm. Contech has utilized a SCS Type II - 12 hr storm to model the water quality event. To validate the sizing, the following parameters were assumed: This storm can then be routed through an appropriately sized Filterra unit, in this case a 13x7. Because the Filterra system can provide up to 9" of ponding, some flow attentuation is possible and the Filterra system is able to accommodate a portion of the water quality volume in the head space and release it at the system's design flow rate. The hydrograph in Figure 2 illustrates this concept. In this example, the 68 cf stored represents the upper portion of the hydrograph between 0.29 cfs and 0.47 cfs. 2. A standard PVC pipe coupling is cast into the wall for easy connection to discharge piping This approach is scalable and can be completed for all Filterra sizes. Table 1 identifies the maximum impervious drainage area to each Filterra unit based on this methodology. Addtionally, for drainage areas that are larger, or not fully impervious, Contech can prepare a custom sizing on a project specific basis to provide the most economical system design. Figure 1. Inflow rate during the 0.60" rainfall WQ Storm event. Figure 2. Inflow rate during the WQ Storm Event compared with the Filterra outflow rate, accounting for 9" ponding within the unit. 1. Boxes are standard depth from rim to outlet: 3.5' for Standard Offline, 4.0' for Internal Bypass Curb. Contact Contech for information on Internal Bypass - Pipe systems. Utilizing the HydroCAD Software, a hydrograph can be derived to represent the design storm (Figure 1). Based on Figure 1, the required treatment flow rate for this drainage area is 0.48 cfs. Project Description Friction Method Manning Formula Solve For Discharge Input Data Roughness Coefficient 0.010 Channel Slope 0.00440 ft/ft Normal Depth 0.67 ft Diameter 0.67 ft Results Discharge 1.06 ft³/s Flow Area 0.35 ft² WettedPerimeter 2.10 ft Hydraulic Radius 0.17 ft Top Width 0.00 ft Critical Depth 0.49 ft Percent Full 100.0 % Critical Slope 0.00570 ft/ft Velocity 3.00 ft/s Velocity Head 0.14 ft Specific Energy 0.81 ft Froude Number 0.00 Maximum Discharge 1.14 ft³/s Discharge Full 1.06 ft³/s Slope Full 0.00440 ft/ft 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 Profile Headloss 0.00 ft Average End Depth Over Rise 0.00 % Normal Depth Over Rise 100.00 % Downstream Velocity Infinity ft/s Filterra Outlet 2/2/2016 2:03:14 PM Bentley Systems, Inc. Haestad Methods Solution Bentley Center FlowMaster V8i (SELECTseries 1) [08.11.01.03] 27 Siemons Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 Page 1 of 2 GVF Output Data Upstream Velocity Infinity ft/s Normal Depth 0.67 ft Critical Depth 0.49 ft Channel Slope 0.00440 ft/ft Critical Slope 0.00570 ft/ft Filterra Outlet 2/2/2016 2:03:14 PM Bentley Systems, Inc. Haestad Methods Solution Bentley Center FlowMaster V8i (SELECTseries 1) [08.11.01.03] 27 Siemons Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 Page 2 of 2 3130 Verona Avenue • Buford, GA 30518 (866) 888-8479 / (770) 932-2443 • Fax: (770) 932-2490 © Nyloplast Inlet Capacity Charts June 2012 0.00 1.00 2.00 3.00 4.00 5.00 6.00 7.00 8.00 9.00 10.00 11.00 0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 0.45 0.50 0.55 0.60 0.65 0.70 0.75 0.80 0.85 0.90 0.95 1.00 1.05 1.10 Capacity (cfs) Head (ft) Nyloplast 2' x 2' Road & Highway Grate Inlet Capacity Chart Project Description Friction Method Manning Formula Solve For Discharge Input Data Roughness Coefficient 0.010 Channel Slope 0.00500 ft/ft Normal Depth 1.00 ft Diameter 1.00 ft Results Discharge 3.27 ft³/s Flow Area 0.79 ft² WettedPerimeter 3.14 ft Hydraulic Radius 0.25 ft Top Width 0.00 ft Critical Depth 0.77 ft Percent Full 100.0 % Critical Slope 0.00559 ft/ft Velocity 4.17 ft/s Velocity Head 0.27 ft Specific Energy 1.27 ft Froude Number 0.00 Maximum Discharge 3.52 ft³/s Discharge Full 3.27 ft³/s Slope Full 0.00500 ft/ft 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 Profile Headloss 0.00 ft Average End Depth Over Rise 0.00 % Normal Depth Over Rise 100.00 % Downstream Velocity Infinity ft/s 2x2 Area Drain to Ex. Inlet 2/2/2016 2:02:05 PM Bentley Systems, Inc. Haestad Methods Solution Bentley Center FlowMaster V8i (SELECTseries 1) [08.11.01.03] 27 Siemons Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 Page 1 of 2 GVF Output Data Upstream Velocity Infinity ft/s Normal Depth 1.00 ft Critical Depth 0.77 ft Channel Slope 0.00500 ft/ft Critical Slope 0.00559 ft/ft 2x2 Area Drain to Ex. Inlet 2/2/2016 2:02:05 PM Bentley Systems, Inc. Haestad Methods Solution Bentley Center FlowMaster V8i (SELECTseries 1) [08.11.01.03] 27 Siemons Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 Page 2 of 2 3130 Verona Avenue • Buford, GA 30518 (866) 888-8479 / (770) 932-2443 • Fax: (770) 932-2490 © Nyloplast Inlet Capacity Charts June 2012 0.00 1.00 2.00 3.00 4.00 5.00 6.00 7.00 8.00 9.00 10.00 11.00 0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 0.45 0.50 0.55 0.60 0.65 0.70 0.75 0.80 0.85 0.90 0.95 1.00 1.05 1.10 Capacity (cfs) Head (ft) Nyloplast 2' x 2' Curb Inlet Standard Grate Inlet Capacity Chart Low Hood Setting (4.47" Curb Setting) Mid Hood Setting (6.47" Curb Setting) High Hood Setting (8.47" Curb Setting) Project Description Friction Method Manning Formula Solve For Discharge Input Data Roughness Coefficient 0.010 Channel Slope 0.01000 ft/ft Normal Depth 1.00 ft Diameter 1.00 ft Results Discharge 4.63 ft³/s Flow Area 0.79 ft² WettedPerimeter 3.14 ft Hydraulic Radius 0.25 ft Top Width 0.00 ft Critical Depth 0.90 ft Percent Full 100.0 % Critical Slope 0.00884 ft/ft Velocity 5.90 ft/s Velocity Head 0.54 ft Specific Energy 1.54 ft Froude Number 0.00 Maximum Discharge 4.98 ft³/s Discharge Full 4.63 ft³/s Slope Full 0.01000 ft/ft 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 Profile Headloss 0.00 ft Average End Depth Over Rise 0.00 % Normal Depth Over Rise 100.00 % Downstream Velocity Infinity ft/s Storm Line B 2/2/2016 2:01:34 PM Bentley Systems, Inc. Haestad Methods Solution Bentley Center FlowMaster V8i (SELECTseries 1) [08.11.01.03] 27 Siemons Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 Page 1 of 2 GVF Output Data Upstream Velocity Infinity ft/s Normal Depth 1.00 ft Critical Depth 0.90 ft Channel Slope 0.01000 ft/ft Critical Slope 0.00884 ft/ft Storm Line B 2/2/2016 2:01:34 PM Bentley Systems, Inc. Haestad Methods Solution Bentley Center FlowMaster V8i (SELECTseries 1) [08.11.01.03] 27 Siemons Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 Page 2 of 2 Survey Area Data: Version 10, Sep 22, 2015 Soil map units are labeled (as space allows) for map scales 1:50,000 or larger. Date(s) aerial images were photographed: Apr 22, 2011—Apr 28, 2011 The orthophoto or other base map on which the soil lines were compiled and digitized probably differs from the background imagery displayed on these maps. As a result, some minor shifting of map unit boundaries may be evident. Hydrologic Soil Group—Larimer County Area, Colorado Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 12/4/2015 Page 2 of 4 the version date(s) listed below. Soil Survey Area: Larimer County Area, Colorado Survey Area Data: Version 10, Sep 22, 2015 Soil map units are labeled (as space allows) for map scales 1:50,000 or larger. Date(s) aerial images were photographed: Apr 22, 2011—Apr 28, 2011 The orthophoto or other base map on which the soil lines were compiled and digitized probably differs from the background imagery displayed on these maps. As a result, some minor shifting of map unit boundaries may be evident. Soil Map—Larimer County Area, Colorado Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 12/4/2015 Page 2 of 3