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BLOOM FILING SIX - PDP230017 - SUBMITTAL DOCUMENTS - ROUND 1 - DRAINAGE REPORT
DRAINAGE & EROSION CONTROL REPORT Tract II, Bloom Filing One City of Fort Collins, CO Prepared for: TDC DEVELOPMENT Dean Barber Dbarber@TDC-DEV.com Prepared by: 16911 Potts Place Mead, CO 80542 Phone: 970.217.9148 Project Number: 1061-3 December 20, 2023 16911 Potts Place, Mead, CO 970.217.9148 troy@i2-consultants.com December 20, 2023 Mr. Wes Lamarque, PE Development Review Engineer City of Fort Collins Utilities 222 Laporte Avenue Fort Collins, CO 80524 RE: Drainage and Erosion Control Report for Tract II, Bloom Filing One, Fort Collins, CO Dear Mr. Lamarque: We are pleased to present this Drainage and Erosion Control Report for Tract II, Bloom Filing One for your review and approval. This report has been prepared in general accordance with the Fort Collins Stormwater Criteria Manual, September 2018 as well as the approved Final Drainage Report, Bloom Filing 1, dated November 14, 20222, prepared by Galloway & Company, Inc. We look forward to your favorable review of this project and report. Please do not hesitate to contact our office if you have any questions. Sincerely, i2 Consultants, Inc. Troy W. Campbell, PE Senior Project Engineer ENGINEER’S CERTIFICATION I hereby certify that this report for the drainage design of Tract II, Bloom Filing One was prepared by me (or under my direct supervision) in accordance with the provisions of the Fort Collins Storm Drainage Criteria Manual for the owners thereof. __________________________________________ Registered Professional Engineer State of Colorado No. 41159 (Seal) Drainage and Erosion Control Report Tract II, Bloom Filing One, Fort Collins, CO December 20, 2023 Page 2 i2 Consultants, Inc. Drainage and Erosion Control Report Tract II, Bloom Filing One Located within the Southwest Quarter of Section 9, Township 7 North, Range 68 West of the 6th P.M. City of Fort Collins, County of Larimer, State of Colorado TABLE OF CONTENTS Page I. GENERAL LOCATION AND DESCRIPTION 3 A. Site Location B. Description of Property II. DRAINAGE BASINS AND SUB-BASINS 4 A. Major Basin B. Sub-basin and Site Drainage III. DRAINAGE DESIGN CRITERIA 4 A. Regulations B. Development Criteria Reference and Constraints C. Hydrological Criteria D. Hydraulic Criteria IV. DRAINAGE FACILITY DESIGN 5 A. General Concept B. Specific Details V. SEDIMENT, EROSION CONTROL AND STORMWATER QUALITY 8 A. Temporary Sediment and Erosion Control B. Permanent Water Quality BMPs VI. CONCLUSIONS 9 A. Compliance with Standards B. Drainage Concept VII. REFERENCES 10 VIII. APPENDICIES 11 Drainage and Erosion Control Report Tract II, Bloom Filing One, Fort Collins, CO December 20, 2023 Page 3 i2 Consultants, Inc. I. GENERAL LOCATION AND DESCRIPTION A. Site Location: The proposed development is located in the southwest quarter of Section 9, Township 7 North, Range 68 West, of the 6th Principal Meridian, City of Fort Collins, County of Larimer, State of Colorado. Furthermore, the project is north of Mulberry Street (and the Frontage Road) and east of Delozier Drive. The current legal description of the property is Tract II, Bloom Filing One. The subject site is currently vacant and has been overlot graded generally according to the Bloom Filing One construction improvements. B. Description of Property: The subject development consists of roughly 5.5 acres. The site is currently undeveloped and the proposed project will consist of roadway connection, utility installation and detention pond regrading. The subject property is being subdivided and this report presents basins for future development. The site currently is vacant but has been overlot graded with the Bloom Filing One improvements. The site is bound by the Lake Canal on the north, Mulberry Street Frontage Road on the south and existing subdivisions on the west and east. The subject site generally slopes from south to north at varying slopes from 0% to 3%. The site has been graded so that the property is out of the 100-year floodplain. The existing runoff from the subject property drains to the north via sheet flow to the existing detention pond along the northern portion of the site. An outlet structure was not installed for the detention pond during the grading for the pond. The subject site is shown as Basin FUT-I in the approved Final Drainage Report, Bloom Filing 1, dated November 14, 20222, prepared by Galloway & Company, Inc. This basin was not included in the hydrology calculations in the report. According to the Natural Resources Conversation Service (NRCS) Web Soil Survey, the native soils in this area are Ascalon sandy loam, 0 to 3 percent slopes (Map Unit Symbol #7), which is a Type B soil and Garrett loam, 0 to 1 percent slopes (Map Unit Symbol #40), which is a Type B soil and Nunn clay loam, wet, 1 to 3 percent slopes (Map Unit Symbol #76), which is a Type C soil. Please refer to the NRCS soils information in the Appendix. Existing drainage facilities near or adjacent to the site include an existing roadside swale along the north side of the Frontage Road as well as the existing detention in the northern portion of the site. Drainage and Erosion Control Report Tract II, Bloom Filing One, Fort Collins, CO December 20, 2023 Page 4 i2 Consultants, Inc. II. DRAINAGE BASINS AND SUB-BASINS A. Major Basin: This site is located within the Boxelder Creek & Cooper Slough Basin as shown on the City of Fort Collins Master Drainage Plan. This basin historically generally flows from northwest to southeast. The Lake Canal runs west to east along the northern portion of the subject site. The site is shown on FEMA panel 08069C0984H, effective 05/02/2012. The subject site is located with Zone X and AE on the current FEMA panel. A LOMR for the subject site has been prepared and submitted to FEMA for the subject site in order to revise the floodplain boundary. B. Sub-basin and Site Drainage: The proposed site generally directs runoff north to the detention pond. Each lot that will be developed shall prepare a site specific drainage report to meet the requirements of the City of Fort Collins and this drainage report. A portion of the subject site will drain from north to south to the existing Frontage Road, due to existing grades and site constraints imposed on the site by the site being raised out of the floodplain. The surrounding property to the east, as well as the Frontage Road are still in the floodplain. The subject site is shown as Basin FUT-I in the approved Final Drainage Report, Bloom Filing 1, dated November 14, 20222, prepared by Galloway & Company, Inc. This basin was not included in the hydrology calculations in the report. There is no offsite runoff that reaches the subject property due to the recent grading associated with the Bloom Filing One improvements. The drainage patterns proposed with the subject improvements are generally consistent with the drainage patterns proposed with the approved Bloom Filing One report. III. DRAINAGE DESIGN CRITERIA A. Regulations: This report has been prepared in general accordance with the Fort Collins Stormwater Criteria Manual, September 2018 and the Urban Storm Drainage Criteria Manual (USDCM). Drainage and Erosion Control Report Tract II, Bloom Filing One, Fort Collins, CO December 20, 2023 Page 5 i2 Consultants, Inc. B. Development Criteria Reference and Constraints: The subject site has been included in the following previous reports: • Final Drainage Report, Bloom Filing 1, dated November 14, 20222, prepared by Galloway & Company, Inc. The site is shown as Basin FUT-I, however hydrologic calculations are not included within the report. Th report for the subject site has been prepared in general accordance with the appropriate City and USDCM criteria and previous reports. C. Hydrological Criteria: Fort Collins Stormwater Criteria Manual, September 2018, as well as the USDCM. There are no deviations from the criteria in this report. The design storms for this project are the 2-year and the 100-year recurrence intervals. Runoff is calculated using the Rational Method since all basins are smaller than 5 acres. The Rational Method calculations are computed by the following: Q = ciA where: Q = Runoff in cubic feet per second c = Calculated runoff coefficient for design event i = Storm intensity in inches/hour A = Basin area in acres Hydrological calculations have been prepared in accordance with the Fort Collins Stormwater Criteria Manual, September 2018 as well as the USDCM. D. Hydraulic Criteria: Rational calculations were prepared using methodology outlined in the Fort Collins Stormwater Criteria Manual, September 2018. Hydraulic capacities were calculated using Hydraflow Express Extension for Autodesk Civil 3D, Version 2021. IV. DRAINAGE FACILITY DESIGN A. General Concept: The drainage patterns associated with the proposed improvements are generally consistent with the existing drainage patterns. Subsequent onsite development shall prepare a site specific drainage report to meet the requirements of the City of Fort Collins and this drainage report. Drainage and Erosion Control Report Tract II, Bloom Filing One, Fort Collins, CO December 20, 2023 Page 6 i2 Consultants, Inc. Site runoff shall be directed to the detention pond in the northern portion of the site. The estimated runoff for the site was determined using the Rational Method, as detailed above. The proposed improvements have been divided into six (6) drainage basins. The basins have been created to direct runoff to existing and proposed facilities and are based on expected future lot development. The detention pond regraded with this development should accommodate developed future onsite flows. This report includes assumptions about future development that shall be verified at the time of each specific development. Additional stormwater attenuation may be required, if future development exceeds the assumptions in this report. B. Specific Details: Basin A Basin A (1.01 acres) is in the southwestern portion of the site and this basin is assumed to contain future commercial development. Assumed imperviousness for this basin is 80%, which corresponds with “Commercial” Land Use as shown in Table 4.1-2 of the City of Fort Collins Criteria. Runoff will generally flow from southwest to northeast. Runoff is expected to flow to Design Point 1 and be conveyed to the proposed detention pond through the northern portion of Basin D. Basin B Basin B (1.23 acres) is in the northwestern portion of the site and this basin is assumed to contain future commercial development. Assumed imperviousness for this basin is 80%, which corresponds with “Commercial” Land Use as shown in Table 4.1-2 of the City of Fort Collins Criteria. Runoff will generally flow from southwest to northeast. Runoff is expected to flow to Design Point 2 and be conveyed to the proposed detention pond through the northern portion of the basin. Basin C Basin C (0.63 acres) is in the northern portion of the site and this basin is assumed to contain future commercial development. Assumed imperviousness for this basin is 80%, which corresponds with “Commercial” Land Use as shown in Table 4.1-2 of the City of Fort Collins Criteria. Runoff will generally flow from southwest to northeast. Runoff is expected to flow to Design Point 3 and be conveyed to the proposed detention pond through the northern portion of Basin C. Basin D Basin D (1.17 acres) is in the southeastern portion of the site and this basin is assumed to contain future commercial development. Assumed imperviousness for this basin is 80%, which corresponds with “Commercial” Land Use as shown in Table 4.1-2 of the City of Fort Collins Criteria. Runoff will generally flow from Drainage and Erosion Control Report Tract II, Bloom Filing One, Fort Collins, CO December 20, 2023 Page 7 i2 Consultants, Inc. southwest to northeast. Runoff is expected to flow to Design Point 4 and be conveyed to the proposed detention pond through the northern portion of Basin D. Basin E Basin E (1.33 acres) is along the northern portion of the subject site and contains the detention pond. The northern portion of the detention is not expected to be regraded with this development. The detention pond outlet will generally be in the center portion of the pond and will convey detained runoff to Lake Canal. Basin F Basin F (0.08) acres is in the southern-middle portion of the site and will contain roadway, sidewalk and landscaping. This basin will flow from north to south the Frontage Road. Due to existing site elevations and constraints, this basin cannot flow to the site detention area. The subject site is shown as Basin FUT-I in the approved Final Drainage Report, Bloom Filing 1, dated November 14, 20222, prepared by Galloway & Company, Inc. This basin was not included in the hydrology calculations in the report. There is an outlet structure design, however the hydrologic and hydraulic calculations are not included in the report. The composite imperviousness calculated for this development (including all basins) is 61.1%, with a “C” value of 0.68. The required 100-year volume is 1.3 ac-ft and the provided volume is 1.3 ac-ft at a release rate of 0.65 cfs. The release rate is based on the existing 2-year runoff from the site. The detention volume is for the difference between the 100-year developed runoff and the existing 2-year runoff. The 100-year water surface elevation will be 4929.50. The detention pond will contain water quality capture volume (WQCV). The WQCV required is 0.15 ac-ft and this will be provided at roughly 4927.0. The pond will have an emergency overflow spillway for a plugged outlet condition or for a storm event greater than the 100-year event. The emergency overflow spillway has been designed to be 40’ long and have a water depth of +/-6”. The runoff through the spillway was calculated by assuming a plugged outlet and determining the runoff at the time the pond is full. The spillway crest elevation is 4930.50, peak elevation through the spillway will be 4931.00. Furthermore, the top of the proposed detention pond will be 4931.00. The detention pond will release via 12” RCP into Lake Canal. The elevation for the outlet pipe is based on the existing ditch cross-section and decreed flow of 158 cfs in the ditch. Drainage and Erosion Control Report Tract II, Bloom Filing One, Fort Collins, CO December 20, 2023 Page 8 i2 Consultants, Inc. V. SEDIMENT, EROSION CONTROL AND STORMWATER QUALITY A. Temporary Sediment and Erosion Control: Several sediment and erosion control measures will be incorporated into the initial phase of construction. The initial sediment and erosion control measures to be installed shall include silt fence, as well as a vehicle tracking control at the construction entrance and sediment control log within the existing swale on the north side of the Frontage Road. Furthermore, additional measures for sediment and erosion control shall consist of providing an area designated for a concrete washout area. A stabilized staging area is proposed to the west of the access road for the subject site. The initial measures for sediment and erosion control shall be maintained and updated as necessary during the interim and final stages of the project. Additionally, any area that has been disturbed by construction activities and left exposed for more than fourteen (14) days, shall receive drilled seeding and straw mulch at 2 tons/acre, until permanent landscaping or ground cover has been provided. Four Step Process to Minimize Adverse Impacts of Urbanization Employing runoff reduction practices: Water Quality will be utilized with this development. Future developments will include landscaping as part of the project and also utilizing LID measures. Implementing best management practices (BMPs): Water Quality will be provided in the detention pond and will be controlled by the water quality plate for the outlet structure. Stabilizing Streams: The runoff from the subject site drains to a detention facility. The runoff release from the overall development will be controlled by the outlet structure for the pond, prior to release into Lake Canal. Implementing site specific and other source control BMPs: A stabilized staging area will be provided to the west of the access road. Appropriate erosion and pollution control shall be installed around the staging area. Each individual lot shall be required to implement site specific and source control BMPs. B. Permanent Water Quality BMPs Permanent Water Quality will be provided in the onsite detention pond. Please refer to the discussion above regarding volume and elevations. Drainage and Erosion Control Report Tract II, Bloom Filing One, Fort Collins, CO December 20, 2023 Page 9 i2 Consultants, Inc. Required Treatment Area The proposed development utilizes water quality practices to the extent practical for the project. Each individual development shall treat new or modified impervious areas per City of Fort Collins criteria in the form of LID measures. Portions of new and modified impervious areas are not able to be treated to the existing conditions surrounding the subject site. Proposed and modified sidewalk and modified parking areas drain away from the subject site to existing conveyances and therefore are not able to be treated. Please refer to the LID Exhibit provided in the Appendix for additional information. VI. CONCLUSIONS A. Compliance with Standards: The drainage design is in general compliance with the Fort Collins Stormwater Criteria Manual, September 2018 as well as the Urban Storm Drainage Criteria Manual (USDCM). Furthermore, the design is in general conformance with the approved Final Drainage Report, Bloom Filing 1, dated November 14, 20222, prepared by Galloway & Company, Inc. There are new and modified impervious areas, such as sidewalks and access that are not able to be treated, per City criteria, since these areas drain away from the subject site to existing conveyances and there is not existing infrastructure to support treatment. B. Drainage Concept: The runoff from this site will be conveyed by existing and proposed storm drainage improvements, including proposed curb, gutter and swales. The drainage design for this project should not negatively impact improvements downstream or the existing storm system. Permanent water quality for the site will be provided through the detention pond to slow runoff and provide a filter for runoff prior to leaving the subject site. Drainage and Erosion Control Report Tract II, Bloom Filing One, Fort Collins, CO December 20, 2023 Page 10 i2 Consultants, Inc. VII.REFERENCES 1. Fort Collins Stormwater Criteria Manual, dated September 2018. 2. Urban Drainage and Flood Control District, Drainage Criteria Manual Volumes 1, Revised August 2018, Volume 2, Revised September 2017 and the Volume 3, dated November 2010 and Updated October 2019. 3. Final Drainage Report, Bloom Filing 1, dated November 14, 20222, prepared by Galloway & Company, Inc. Drainage and Erosion Control Report Tract II, Bloom Filing One, Fort Collins, CO December 20, 2023 Page 11 i2 Consultants, Inc. VIII.APPENDICIES Vicinity Map FEMA & Existing Geotechnical Information Hydrologic Calculations Hydraulic Calculations Excerpts from Previous Reports Charts and Figures Vicinity Map © 2023 Microsoft Corporation © 2023 TomTom TRACT II, BLOOM FILING ONE FORT COLLINS, CO VICINITY MAP JLB C: \ U s e r s \ t r o y \ D r o p b o x \ I 2 \ P r o j e c t s \ 1 0 6 1 - 3 B l o o m \ D W G \ S h e e t s \ B l o o m _ C V . d w g , 1 2 / 1 9 / 2 0 2 3 1 : 4 5 : 3 9 P M , D W G T o P D F . p c 3 A-1 i2 Consultants, Inc. FEMA & Existing Geotechnical Information National Flood Hazard Layer FIRMette 0 500 1,000 1,500 2,000250 Feet Ü SEE FIS REPORT FOR DETAILED LEGEND AND INDEX MAP FOR FIRM PANEL LAYOUT SPECIAL FLOOD HAZARD AREAS Without Base Flood Elevation (BFE) Zone A, V, A99 With BFE or DepthZone AE, AO, AH, VE, AR Regulatory Floodway 0.2% Annual Chance Flood Hazard, Areas of 1% annual chance flood with average depth less than one foot or with drainage areas of less than one square mileZone X Future Conditions 1% Annual Chance Flood HazardZone X Area with Reduced Flood Risk due to Levee. See Notes.Zone X Area with Flood Risk due to LeveeZone D NO SCREEN Area of Minimal Flood Hazard Zone X Area of Undetermined Flood HazardZone D Channel, Culvert, or Storm Sewer Levee, Dike, or Floodwall Cross Sections with 1% Annual Chance 17.5 Water Surface Elevation Coastal Transect Coastal Transect Baseline Profile Baseline Hydrographic Feature Base Flood Elevation Line (BFE) Effective LOMRs Limit of Study Jurisdiction Boundary Digital Data Available No Digital Data Available Unmapped This map complies with FEMA's standards for the use of digital flood maps if it is not void as described below. The basemap shown complies with FEMA's basemap accuracy standards The flood hazard information is derived directly from the authoritative NFHL web services provided by FEMA. This map was exported on 12/13/2023 at 9:33 PM and does not reflect changes or amendments subsequent to this date and time. The NFHL and effective information may change or become superseded by new data over time. This map image is void if the one or more of the following map elements do not appear: basemap imagery, flood zone labels, legend, scale bar, map creation date, community identifiers, FIRM panel number, and FIRM effective date. Map images for unmapped and unmodernized areas cannot be used for regulatory purposes. Legend OTHER AREAS OF FLOOD HAZARD OTHER AREAS GENERAL STRUCTURES OTHER FEATURES MAP PANELS 8 B 20.2 The pin displayed on the map is an approximate point selected by the user and does not represent an authoritative property location. 1:6,000 105°1'28"W 40°35'10"N 105°0'51"W 40°34'43"N Basemap Imagery Source: USGS National Map 2023 B-1 Soil Map—Larimer County Area, Colorado (Tract II, Bloom Filing One) Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 12/13/2023 Page 1 of 3 44 9 2 2 7 0 44 9 2 3 1 0 44 9 2 3 5 0 44 9 2 3 9 0 44 9 2 4 3 0 44 9 2 4 7 0 44 9 2 5 1 0 44 9 2 5 5 0 44 9 2 5 9 0 44 9 2 2 7 0 44 9 2 3 1 0 44 9 2 3 5 0 44 9 2 3 9 0 44 9 2 4 3 0 44 9 2 4 7 0 44 9 2 5 1 0 44 9 2 5 5 0 44 9 2 5 9 0 498250 498290 498330 498370 498410 498450 498490 498250 498290 498330 498370 498410 498450 498490 40° 35' 2'' N 10 5 ° 1 ' 1 4 ' ' W 40° 35' 2'' N 10 5 ° 1 ' 4 ' ' W 40° 34' 52'' N 10 5 ° 1 ' 1 4 ' ' W 40° 34' 52'' N 10 5 ° 1 ' 4 ' ' W N Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 13N WGS84 0 50 100 200 300 Feet 0 20 40 80 120 Meters Map Scale: 1:1,570 if printed on A portrait (8.5" x 11") sheet. Soil Map may not be valid at this scale. B-2 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: 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 Survey Area Data: Version 18, Aug 24, 2023 Soil map units are labeled (as space allows) for map scales 1:50,000 or larger. Date(s) aerial images were photographed: Jul 2, 2021—Aug 25, 2021 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 (Tract II, Bloom Filing One) Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 12/13/2023 Page 2 of 3 B-3 Map Unit Legend Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI 7 Ascalon sandy loam, 0 to 3 percent slopes 3.6 51.3% 40 Garrett loam, 0 to 1 percent slopes 3.1 44.8% 76 Nunn clay loam, wet, 1 to 3 percent slopes 0.3 3.9% Totals for Area of Interest 7.0 100.0% Soil Map—Larimer County Area, Colorado Tract II, Bloom Filing One Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 12/13/2023 Page 3 of 3 B-4 Hydrologic Soil Group—Larimer County Area, Colorado (Tract II, Bloom Filing One) Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 12/13/2023 Page 1 of 4 44 9 2 2 7 0 44 9 2 3 1 0 44 9 2 3 5 0 44 9 2 3 9 0 44 9 2 4 3 0 44 9 2 4 7 0 44 9 2 5 1 0 44 9 2 5 5 0 44 9 2 5 9 0 44 9 2 2 7 0 44 9 2 3 1 0 44 9 2 3 5 0 44 9 2 3 9 0 44 9 2 4 3 0 44 9 2 4 7 0 44 9 2 5 1 0 44 9 2 5 5 0 44 9 2 5 9 0 498250 498290 498330 498370 498410 498450 498490 498250 498290 498330 498370 498410 498450 498490 40° 35' 2'' N 10 5 ° 1 ' 1 4 ' ' W 40° 35' 2'' N 10 5 ° 1 ' 4 ' ' W 40° 34' 52'' N 10 5 ° 1 ' 1 4 ' ' W 40° 34' 52'' N 10 5 ° 1 ' 4 ' ' W N Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 13N WGS84 0 50 100 200 300 Feet 0 20 40 80 120 Meters Map Scale: 1:1,570 if printed on A portrait (8.5" x 11") sheet. Soil Map may not be valid at this scale. B-5 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: 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 Survey Area Data: Version 18, Aug 24, 2023 Soil map units are labeled (as space allows) for map scales 1:50,000 or larger. Date(s) aerial images were photographed: Jul 2, 2021—Aug 25, 2021 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 (Tract II, Bloom Filing One) Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 12/13/2023 Page 2 of 4 B-6 Hydrologic Soil Group Map unit symbol Map unit name Rating Acres in AOI Percent of AOI 7 Ascalon sandy loam, 0 to 3 percent slopes B 3.6 51.3% 40 Garrett loam, 0 to 1 percent slopes B 3.1 44.8% 76 Nunn clay loam, wet, 1 to 3 percent slopes C 0.3 3.9% Totals for Area of Interest 7.0 100.0% 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. Hydrologic Soil Group—Larimer County Area, Colorado Tract II, Bloom Filing One Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 12/13/2023 Page 3 of 4 B-7 Rating Options Aggregation Method: Dominant Condition Component Percent Cutoff: None Specified Tie-break Rule: Higher Hydrologic Soil Group—Larimer County Area, Colorado Tract II, Bloom Filing One Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 12/13/2023 Page 4 of 4 B-8 i2 Consultants, Inc. Hydrologic Calculations Runoff Coeffecients Sub-Basins C-1 Project: Tract II Bloom Filing One i2 Location:Consultants, Inc. Fort Collins, CO 16911 Potts Place, Mead, CO Project Number:1061-3 970.217.9148 Date: 12/20/2023 troy@i2-consultants.com All calculations presented are based upon the criteria set forth in the City of Fort Collins Storm Drainage Design Criteria 9/1/2018 Basin A (ac) (sq.ft) (%) Design Point Surface Improvement Area Area C I Comments 1 % of site area Lawns, Sandy soil (flat <2%) 0.00 0.0 0.15 2.00 0.0% Curb & gutter and walks 0.00 0.0 0.95 100.00 0.0% Paved Parking & Drives 0.00 0.0 0.95 100.00 0.0% Commercial Area 1.02 44288.0 0.85 80.00 100.0% Avg. 0.85 80.00 100.0% Total Area 1.02 0.85 80.00 Basin B (ac) (sq.ft) (%) Design Point Surface Improvement Area Area C I Comments 2 % of site area Lawns, Sandy soil (flat <2%) 0.00 0.0 0.15 2.00 0.0% Curb & gutter and walks 0.00 0.0 0.95 100.00 0.0% Paved Parking & Drives 0.00 0.0 0.95 100.00 0.0% Commercial Area 1.23 53623.0 0.85 80.00 100.0% Avg. 0.85 80.00 100.0% Total Area 1.23 0.85 80.00 Basin C (ac) (sq.ft) (%) Design Point Surface Improvement Area Area C I Comments 3 % of site area Lawns, Sandy soil (flat <2%) 0.00 0.0 0.15 2.00 0.0% Curb & gutter and walks 0.00 0.0 0.95 100.00 0.0% Paved Parking & Drives 0.00 0.0 0.95 100.00 0.0% Commercial Area 0.63 27548.0 0.85 80.00 100.0% Avg. 0.85 80.00 100.0% Total Area 0.63 0.85 80.00 Basin D (ac) (sq.ft) (%) Design Point Surface Improvement Area Area C I Comments 4 % of site area Lawns, Sandy soil (flat <2%) 0.00 0.0 0.15 2.00 0.0% Curb & gutter and walks 0.00 0.0 0.95 100.00 0.0% Paved Parking & Drives 0.00 0.0 0.95 100.00 0.0% Commercial Area 1.17 50979.0 0.85 80.00 100.0% Avg. 0.85 80.00 100.0% Total Area 1.17 0.85 80.00 Bloom_Imperv.xlsx\Sub-Basins 12/19/2023 Runoff Coeffecients Sub-Basins C-2 Basin E (ac) (sq.ft) (%) Design Point Surface Improvement Area Area C I Comments 5 % of site area Lawns, Sandy soil (flat <2%) 1.33 57835.0 0.15 2.00 100.0% Curb & gutter and walks 0.00 0.0 0.95 100.00 0.0% Paved Parking & Drives 0.00 0.0 0.95 100.00 0.0% Commercial Area 0.00 0.0 0.85 80.00 0.0% Avg. 0.15 2.00 100.0% Total Area 1.33 0.15 2.00 Basin F (ac) (sq.ft) (%) Design Point Surface Improvement Area Area C I Comments 6 % of site area Lawns, Sandy soil (flat <2%) 0.01 580.0 0.15 2.00 16.2% Curb & gutter and walks 0.02 855.0 0.95 100.00 23.9% Paved Parking & Drives 0.05 2135.0 0.95 100.00 59.8% Commercial Area 0.00 0.0 0.85 80.00 0.0% Avg. 0.82 84.08 100.0% Total Area 0.08 0.82 84.08 Overall Site (ac) (sq.ft) (%) Design Point publish Area Area C I Comments 5 % of site area Lawns, Sandy soil (flat <2%) 1.34 58415.0 0.15 2.00 24.6% Curb & gutter and walks 0.02 855.0 0.95 100.00 0.4% Paved Parking & Drives 0.05 2135.0 0.95 100.00 0.9% Commercial Area 4.05 176438.0 0.85 80.00 74.2% Avg. 0.68 61.09 100.0% Total Area 5.46 237,843.00 0.68 61.09 Bloom_Imperv.xlsx\Sub-Basins 12/19/2023 C-3 PROJECT:Tract II Bloom Filing One CALCULATED BY:i2 Consultants, Inc.DATE:12/20/2023 Cf = 1.00 FINAL REMARKS tc BASIN DP AREA C C*Cf Length Slope ti Length Slope R V tt tc Total L tc ID Ac Ft % min Ft (ft/ft) Ft fps min min ft min min (0) (1) (2) (3) (4) (5) (6) (7) (8) (8a) (9) (10) (11) (12) (13) (14) 1 A 1 1.02 0.85 0.85 25 2.0 1.9 275 0.010 1.0 1.5 3.1 4.9 300 11.7 5.0 Use Tc = 5.0 mins 2 B 2 1.23 0.85 0.85 25 2.0 1.9 325 0.01 1.0 1.5 3.6 5.5 350 11.9 5.5 Use Tc = 5.5 mins 3 C 3 0.63 0.85 0.85 25 2.0 1.9 175 0.01 1.0 1.5 1.9 3.8 200 11.1 5.0 Use Tc = 5.0 mins 4 D 4 1.17 0.85 0.85 25 2.0 1.9 250 0.01 1.0 1.5 2.8 4.6 275 11.5 5.0 Use Tc = 5.0 mins 5 E 5 1.33 0.15 0.15 50 10.0 5.8 300 0.005 1.0 0.7 7.1 13.0 350 11.9 11.9 Use Tc = 11.9 mins 6 F 6 0.08 0.82 0.82 15 2.0 1.6 50 0.04 1.0 2.5 0.3 1.9 65 10.4 5.0 Use Tc = 5.0 mins 7 All 5 5.46 0.68 0.68 25 2.0 3.1 510 0.01 1.0 1.5 5.7 8.8 535 13.0 8.8 Use Tc = 8.8 mins EX 5 5.46 0.10 0.10 300 1.0 32.4 200 0.0 1.0 1.0 3.3 35.7 235.7 11.3 35.7 Use Tc = 35.7 mins Equations: Urbanized Tov tt =L tc =(L/180)+10 60V V=CvSw0.5 (1)(2) or Fig. 3-3 (3) Velocity V (1.4/n)*(R^2/3))*0.5) S in ft/ft, R = Area/Wetted Perimeter in ft, n = Roughness Coeff. S ^1/3 Rural/Non-urban (URBANIZED) RURAL OR NON URBANIZED TIME OF CONCENTRATION - 2-YEAR 1.87(1.1-CC f )*D^1/2 DATA SUB-BASIN INITIAL/OVERLAND TIME (Tov) TRAVEL TIME (tt) tc CHECK C-4 PROJECT:Tract II Bloom Filing One CALCULATED BY:i2 Consultants, Inc.DATE:12/20/2023 Cf = 1.25 FINAL REMARKS tc BASIN DP AREA C C*Cf Length Slope ti Length Slope R V tt tc Total L tc ID Ac Ft % min Ft % Ft fps min min ft min min (0) (1) (2) (3) (4) (5) (6) (7) (8) (8a) (9) (10) (11) (12) (13) (14) 1 A 1 1.02 0.85 1.00 25 2.0 0.7 275 0.01 1.0 1.5 3.1 3.8 300 11.7 5.0 Use Tc = 5.0 mins 2 B 2 1.23 0.85 1.00 25 2.0 0.7 325 0.01 1.0 1.5 3.6 4.4 350 11.9 5.0 Use Tc = 5.0 mins 3 C 3 0.63 0.85 1.00 25 2.0 0.7 175 0.01 1.0 1.5 1.9 2.7 200 11.1 5.0 Use Tc = 5.0 mins 4 D 4 1.17 0.85 1.00 25 2.0 0.7 250 0.01 1.0 1.5 2.8 3.5 275 11.5 5.0 Use Tc = 5.0 mins 5 E 5 1.33 0.15 0.19 50 10.0 5.6 300 0.005 1.0 0.7 7.1 12.7 350 11.9 11.9 Use Tc = 11.9 mins 6 F 6 0.08 0.82 1.00 15 2.0 0.6 50 0.04 0.0 2.5 0.0 0.6 65 10.4 5.0 Use Tc = 5.0 mins 7 All 5 5.46 0.68 0.85 25 2.0 1.9 510 0.01 1.0 1.5 5.7 7.5 535 13.0 7.5 Use Tc = 7.5 mins Equations: Urbanized Tov tt =L tc =(L/180)+10 60V V=CvSw0.5 (1)(2) or Fig. 3-3 (3) Velocity V (1.4/n)*(R^2/3))*0.5) S in ft/ft, R = Area/Wetted Perimeter in ft, n = Roughness Coeff. RURAL OR NON URBANIZED TIME OF CONCENTRATION - 100-YEAR 1.87(1.1-CC f )*D^1/2 DATA SUB-BASIN INITIAL/OVERLAND TIME (Tov) TRAVEL TIME (tt) tc CHECK S ^1/3 Rural/Non-urban (URBANIZED) Rational Method Direct Runoff - 2-YR C-5 Project: Tract II, Bloom Filing One i2 Consultants, Inc. Location:16911 Potts Place, Mead, CO Fort Collins, Colorado 970.217.9148 Project Number:1061-3 troy@i2-consultants.com Date: 12/20/2023 Rational Method:Q = CfCIA Q: Q: Runoff in cfs (peak) C: C: Runoff Coefficient Cf: Cf: Frequency Adjustment Factor I: I: Rainfall Intensity (in/hr) for design event A: A: Basin Area (acres) 2-YEAR Design Point Basin ID Area C CfC tc I Q2 1 A 1.02 0.85 0.85 5.0 2.85 2.46 2.4 cfs/acre 2 B 1.23 0.85 0.85 5.5 2.76 2.89 2.3 cfs/acre 3 C 0.63 0.85 0.85 5.0 2.85 1.53 2.4 cfs/acre 4 D 1.17 0.85 0.85 5.0 2.85 2.84 2.4 cfs/acre 5 E 1.33 0.15 0.15 11.9 2.06 0.41 0.3 cfs/acre 6 F 0.08 0.82 0.82 5.0 2.85 0.19 2.3 cfs/acre 5 ALL 5.46 0.68 0.68 8.8 2.30 8.53 1.6 cfs/acre 5 EX 5.46 0.10 0.10 35.7 1.16 0.63 0.12 cfs/acre C:\Users\troy\Dropbox\I2\Projects\1061-3 Bloom\Documents\Drainage\Bloom_rational.xlsx 12/19/2023 Pond release rate Rational Method Direct Runoff - 100-YR C-6 Project: Tract II, Bloom Filing One i2 Consultants, Inc. Location:16911 Potts Place, Mead, CO Fort Collins, Colorado 970.217.9148 Project Number:1061-3 troy@i2-consultants.com Date: 12/20/2023 Rational Method:Q = CfCIA Q: Q: Runoff in cfs (peak) C: C: Runoff Coefficient Cf: Cf: Frequency Adjustment Factor I: I: Rainfall Intensity (in/hr) for design event A: A: Basin Area (acres) 100-YEAR Design Point Basin ID Area C CfC tc I Q100 1 A 1.02 0.85 1.00 5.0 9.95 10.12 10.0 cfs/acre 2 B 1.23 0.85 1.00 5.0 9.95 12.25 10.0 cfs/acre 3 C 0.63 0.85 1.00 5.0 9.95 6.29 10.0 cfs/acre 4 D 1.17 0.85 1.00 5.0 9.95 11.64 10.0 cfs/acre 5 E 1.33 0.15 0.19 11.9 7.19 1.79 1.3 cfs/acre 6 F 0.08 0.82 1.00 5.0 9.95 0.82 10.0 cfs/acre 5 ALL 5.46 0.68 0.85 7.5 8.59 39.83 7.3 cfs/acre C:\Users\troy\Dropbox\I2\Projects\1061-3 Bloom\Documents\Drainage\Bloom_rational.xlsx 12/19/2023 i2 Consultants, Inc. Hydraulic Calculations 100 Year Volume 12/19/2023 E-1 Project: Tract II Bloom Filing One Location: Fort Collins, Colorado Project Number:1061-3 Date: Dec-23 ft3 acre-ft. 'C' value 0.68 57,182.4 1.31 'C' * 1.25 0.85 Area 5.5 acres Release Rate 0.66 cfs (Area X 0.12 cfs/ac.) DETENTION POND SIZING (100-Year) TIME TIME INTENSITY Q 100 Runoff Release Required Required cum 100 year Volume Cum total Detention Detention (mins) (secs) (in/hr) (cfs) (ft^3) (ft^3) (ft^3) (ac-ft) 0 0 0 0.00 0 0.0 0.0 0.0000 5 300 9.950 46.52 13954.88 198.0 13756.9 0.3158 10 600 7.720 36.09 21654.6 396.0 21258.6 0.4880 15 900 6.520 30.48 27432.9 594.0 26838.9 0.6161 20 1200 5.600 26.18 31416 792.0 30624.0 0.7030 25 1500 4.980 23.28 34922.25 990.0 33932.3 0.7790 30 1800 4.520 21.13 38035.8 1188.0 36847.8 0.8459 35 2100 4.080 19.07 40055.4 1386.0 38669.4 0.8877 40 2400 3.740 17.48 41962.8 1584.0 40378.8 0.9270 45 2700 3.460 16.18 43673.85 1782.0 41891.9 0.9617 50 3000 3.230 15.10 45300.75 1980.0 43320.8 0.9945 55 3300 3.030 14.17 46745.33 2178.0 44567.3 1.0231 60 3600 2.860 13.37 48133.8 2376.0 45757.8 1.0505 65 3900 2.720 12.72 49592.4 2574.0 47018.4 1.0794 70 4200 2.590 12.11 50854.65 2772.0 48082.7 1.1038 75 4500 2.480 11.59 52173 2970.0 49203.0 1.1295 80 4800 2.380 11.13 53407.2 3168.0 50239.2 1.1533 85 5100 2.290 10.71 54599.33 3366.0 51233.3 1.1762 90 5400 2.210 10.33 55791.45 3564.0 52227.5 1.1990 95 5700 2.130 9.96 56759.18 3762.0 52997.2 1.2166 100 6000 2.060 9.63 57783 3960.0 53823.0 1.2356 105 6300 2.000 9.35 58905 4158.0 54747.0 1.2568 110 6600 1.940 9.07 59858.7 4356.0 55502.7 1.2742 115 6900 1.890 8.84 60966.68 4554.0 56412.7 1.2951 120 7200 1.840 8.60 61934.4 4752.0 57182.4 1.3127 100-Year Volume 125 7500 1.790 8.37 62761.88 4950.0 57811.9 1.3272 130 7800 1.750 8.18 63813.75 5148.0 58665.8 1.3468 135 8100 1.710 7.99 64753.43 5346.0 59407.4 1.3638 140 8400 1.670 7.81 65580.9 5544.0 60036.9 1.3783 145 8700 1.630 7.62 66296.18 5742.0 60554.2 1.3901 150 9000 1.600 7.48 67320 5940.0 61380.0 1.4091 155 9300 1.570 7.34 68259.68 6138.0 62121.7 1.4261 160 9600 1.540 7.20 69115.2 6336.0 62779.2 1.4412 165 9900 1.510 7.06 69886.58 6534.0 63352.6 1.4544 170 10200 1.480 6.92 70573.8 6732.0 63841.8 1.4656 175 10500 1.450 6.78 71176.88 6930.0 64246.9 1.4749 180 10800 1.420 6.64 71695.8 7128.0 64567.8 1.4823 185 11100 1.400 6.55 72649.5 7326.0 65323.5 1.4996 190 11400 1.380 6.45 73547.1 7524.0 66023.1 1.5157 195 11700 1.360 6.36 74388.6 7722.0 66666.6 1.5305 200 12000 1.340 6.26 75174 7920.0 67254.0 1.5439 205 12300 1.320 6.17 75903.3 8118.0 67785.3 1.5561 210 12600 1.300 6.08 76576.5 8316.0 68260.5 1.5670 215 12900 1.280 5.98 77193.6 8514.0 68679.6 1.5767 220 13200 1.260 5.89 77754.6 8712.0 69042.6 1.5850 225 13500 1.240 5.80 78259.5 8910.0 69349.5 1.5920 230 13800 1.220 5.70 78708.3 9108.0 69600.3 1.5978 235 14100 1.210 5.66 79760.18 9306.0 70454.2 1.6174 240 14400 1.200 5.61 80784 9504.0 71280.0 1.6364 Required detention Page 1 D-1 Project: Basin ID: WQCV Design Volume (Input): Catchment Imperviousness, Ia =61.0 percent Catchment Area, A = 5.50 acres Diameter of holes, D = 0.794 inches Depth at WQCV outlet above lowest perforation, H = 1 feet Number of holes per row, N = 1 Vertical distance between rows, h = 4.00 inches OR Number of rows, NL = 2.00 Orifice discharge coefficient, Co =0.65 Height of slot, H = inches Time to Drain the Pond = 40 hours Watershed Design Information (Input):1 Percent Soil Type A = % Percent Soil Type B = 100 % Percent Soil Type C/D = % Outlet Design Information (Output): Water Quality Capture Volume, WQCV = 0.275 watershed inches Water Quality Capture Volume (WQCV) = 0.126 acre-feet 0.00 Design Volume (WQCV / 12 * Area * 1.2) Vol = 0.151 acre-feet Outlet area per row, Ao = 0.49 square inches Total opening area at each row based on user-input above, Ao = 0.50 square inches Total opening area at each row based on user-input above, Ao = 0.003 square feet 3 Row 1 Row 2 Row 3 Row 4 Row 5 Row 6 Row 7 Row 8 Row 9 Row 10 Row 11 Row 12 Row 13 Row 14 Row 15 Row 16 Row 17 Row 18 Row 19 Row 20 Row 21 Row 22 Row 23 Row 23 4925.50 4925.83 Flow 4925.50 0.0000 0.0000 0.00 4925.75 0.0090 0.0000 0.01 4926.00 0.0127 0.0074 0.02 4926.25 0.0155 0.0116 0.03 4926.50 0.0179 0.0147 0.03 4926.75 0.0201 0.0172 0.04 4927.00 0.0220 0.0194 0.04 4927.25 0.0237 0.0214 0.05 4927.50 0.0254 0.0232 0.05 4927.75 0.0269 0.0249 0.05 4928.00 0.0284 0.0264 0.05 4928.25 0.0297 0.0279 0.06 4928.50 0.0311 0.0293 0.06 4928.75 0.0323 0.0306 0.06 4929.00 0.0336 0.0319 0.07 4929.25 0.0347 0.0332 0.07 4929.50 0.0359 0.0344 0.07 4929.75 0.0370 0.0355 0.07 4930.00 0.0380 0.0366 0.07 4930.25 0.0391 0.0377 0.08 4930.50 0.0401 0.0388 0.08 4930.75 0.0411 0.0398 0.08 4931.00 0.0421 0.0408 0.08 #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A Override Area Row 1 Override Area Row 2 Override Area Row 3 Override Area Row 4 Override Area Row 5 Override Area Row 6 Override Area Row 7 Override Area Row 8 Override Area Row 9 Override Area Row 10 Override Area Row 11 Override Area Row 12 Override Area Row 13 Override Area Row 14 Override Area Row 15 Override Area Row 16 Override Area Row 17 Override Area Row 18 Override Area Row 19 Override Area Row 20 Override Area Row 21 Override Area Row 22 Override Area Row 23 Override Area Row 24 Central Elevations of Rows of Holes in feet Collection Capacity for Each Row of Holes in cfs STAGE-DISCHARGE SIZING OF THE WATER QUALITY CAPTURE VOLUME (WQCV) OUTLET Tract II Bloom Filing One Site Bloom WQ UD-Detention_2.35.xls, WQCV 12/19/2023, 2:08 PM D-2 Worksheet Protected Project: Basin ID: STAGE-DISCHARGE SIZING OF THE WATER QUALITY CAPTURE VOLUME (WQCV) OUTLET Tract II Bloom Filing One Site 4925.00 4926.00 4927.00 4928.00 4929.00 4930.00 4931.00 4932.00 0.00 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09 St a g e ( f e e t , e l e v . ) Discharge (cfs) STAGE-DISCHARGE CURVE FOR THE WQCV OUTLET STRUCTURE Bloom WQ UD-Detention_2.35.xls, WQCV 12/19/2023, 2:08 PM D-3 Project: Basin ID: Design Information (Input): Width of Basin Bottom, W = ft Right Triangle OR… Length of Basin Bottom, L = ft Isosceles Triangle OR… Dam Side-slope (H:V), Zd =ft/ft Rectangle OR… Circle / Ellipse OR… Irregular (Use Overide values in cells G32:G52) MINOR MAJOR Storage Requirement from Sheet 'Modified FAA': 0.41 1.40 acre-ft. Stage-Storage Relationship:Storage Requirement from Sheet 'Hydrograph': acre-ft. Storage Requirement from Sheet 'Full-Spectrum': acre-ft. Labels Water Side Basin Basin Surface Surface Volume Surface Volume Target Volumes for WQCV, Minor, Surface Slope Width at Length at Area at Area at Below Area at Below for WQCV, Minor, & Major Storage Elevation (H:V) Stage Stage Stage Stage Stage Stage Stage & Major Storage Stages ft ft/ft ft ft ft2 ft2 User ft3 acres acre-ft Volumes (input) (input)Below El.(output) (output) (output)Overide (output) (output) (output) (for goal seek) 4925.50 (input)0 0.000 0.000 4926.00 0.00 0.00 2,740 685 0.063 0.016 4926.50 0.00 0.00 7,225 3,176 0.166 0.073 4927.00 0.00 0.00 10,000 7,483 0.230 0.172 WQCV 4927.50 0.00 0.00 15,000 13,733 0.344 0.315 4928.00 0.00 0.00 19,000 22,233 0.436 0.510 4928.50 0.00 0.00 25,000 33,233 0.574 0.763 4929.00 0.00 0.00 26,000 45,983 0.597 1.056 4929.50 0.00 0.00 27,000 59,233 0.620 1.360 100-WSEL 4930.00 0.00 0.00 30,000 73,483 0.689 1.687 4930.50 0.00 0.00 33,000 89,233 0.758 2.048 4931.00 0.00 0.00 35,000 106,233 0.803 2.439 #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A STAGE-STORAGE SIZING FOR DETENTION BASINS Tract Ii Bloom Filing One Check Basin Shape Site Bloom WQ UD-Detention_2.35.xls, Basin 12/19/2023, 2:10 PM D-4 Project: Basin ID: STAGE-STORAGE SIZING FOR DETENTION BASINS 0.00 1000.00 2000.00 3000.00 4000.00 5000.00 6000.00 0.00 0.50 1.00 1.50 2.00 2.50 3.00 St a g e ( f t . e l e v . ) Storage (acre-feet) STAGE-STORAGE CURVE FOR THE POND Bloom WQ UD-Detention_2.35.xls, Basin 12/19/2023, 2:10 PM D-5 Project: Basin ID: X 1 #1 Vertical #2 Vertical Sizing the Restrictor Plate for Circular Vertical Orifices or Pipes (Input)Orifice Orifice Water Surface Elevation at Design Depth Elev: WS = 4,930.00 feet Pipe/Vertical Orifice Entrance Invert Elevation Elev: Invert = 4,925.50 feet Required Peak Flow through Orifice at Design Depth Q = 0.66 cfs Pipe/Vertical Orifice Diameter (inches) Dia = 12.0 inches Orifice Coefficient Co =0.65 Full-flow Capacity (Calculated) Full-flow area Af = 0.79 sq ft Half Central Angle in Radians Theta = 3.14 rad Full-flow capacity Qf = 8.2 cfs Percent of Design Flow = 1241% Calculation of Orifice Flow Condition Half Central Angle (0<Theta<3.1416) Theta = 0.74 rad Flow area Ao =0.06 sq ft Top width of Orifice (inches)To =8.08 inches Height from Invert of Orifice to Bottom of Plate (feet)Yo =0.13 feet Elevation of Bottom of Plate Elev Plate Bottom Edge = 4,925.63 feet Resultant Peak Flow Through Orifice at Design Depth Qo =0.7 cfs Width of Equivalent Rectangular Vertical Orifice Equivalent Width = 0.46 feet Tract II Bloom Filing One Site RESTRICTOR PLATE SIZING FOR CIRCULAR VERTICAL ORIFICES Bloom WQ UD-Detention_2.35.xls, Restrictor Plate 12/19/2023, 2:08 PM D-6 Project: Basin ID: Design Information (Input):#1 Horiz. #2 Horiz. #1 Vert. #2 Vert. Circular Opening: Diameter in Inches Dia. = 12.00 inches OR Rectangular Opening: Width in Feet W = 2.00 ft. Length (Height for Vertical) L or H = 2.00 ft. Percentage of Open Area After Trash Rack Reduction % open = 70 12 % Orifice Coefficient Co = 0.65 0.65 Weir Coefficient Cw = 2.65 Orifice Elevation (Bottom for Vertical) Eo = 4926.50 4,925.57 ft. Calculation of Collection Capacity: OPTIONAL: User-Overide Net Opening Area Ao = sq. ft. Perimeter as Weir Length Lw = 6.80 ft. OPTIONAL: User-Overide Weir Length Lw =ft. Top Elevation of Vertical Orifice Opening, Top =4926.57 ft. Center Elevation of Vertical Orifice Opening, Cen =4926.07 ft. Horizontal Orifices Vertical Orifices Labels Water WQCV #1 Horiz. #1 Horiz. #2 Horiz. #2 Horiz. #1 Vert. #2 Vert.Total Target Volumes for WQCV, Minor,Surface Plate/Riser Weir Orifice Weir Orifice Collection Collection Collection for WQCV, Minor, & Major Storage Elevation Flow Flow Flow Flow Flow Capacity Capacity Capacity & Major Storage W.S. Elevations ft cfs cfs cfs cfs cfs cfs cfs cfs Volumes (input)(linked) (User-linked) (output) (output) (output) (output) (output) (output)(output)(link for goal seek) 4925.50 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 4926.00 0.01 0.00 0.00 0.00 0.00 0.10 0.00 0.01 4926.50 0.02 0.00 0.00 0.00 0.00 0.31 0.00 0.02 4927.00 0.03 6.37 10.33 0.00 0.00 0.47 0.00 0.47 4927.50 0.03 18.02 14.61 0.00 0.00 0.59 0.00 0.59 4928.00 0.04 33.10 17.89 0.00 0.00 0.68 0.00 0.68 4928.50 0.04 50.97 20.66 0.00 0.00 0.77 0.00 0.77 4929.00 0.05 71.23 23.09 0.00 0.00 0.84 0.00 0.84 4929.50 0.05 93.63 25.30 0.00 0.00 0.91 0.00 0.91 4930.00 0.05 117.99 27.32 0.00 0.00 0.97 0.00 0.97 4930.50 0.05 144.16 29.21 0.00 0.00 1.03 0.00 1.03 4931.00 0.06 172.02 30.98 0.00 0.00 1.09 0.00 1.09 0.06 #N/A #N/A #N/A #N/A #N/A 0.00 #N/A 0.06 #N/A #N/A #N/A #N/A #N/A 0.00 #N/A 0.07 #N/A #N/A #N/A #N/A #N/A 0.00 #N/A 0.07 #N/A #N/A #N/A #N/A #N/A 0.00 #N/A 0.07 #N/A #N/A #N/A #N/A #N/A 0.00 #N/A 0.07 #N/A #N/A #N/A #N/A #N/A 0.00 #N/A 0.07 #N/A #N/A #N/A #N/A #N/A 0.00 #N/A 0.08 #N/A #N/A #N/A #N/A #N/A 0.00 #N/A 0.08 #N/A #N/A #N/A #N/A #N/A 0.00 #N/A 0.08 #N/A #N/A #N/A #N/A #N/A 0.00 #N/A 0.08 #N/A #N/A #N/A #N/A #N/A 0.00 #N/A #N/A #N/A #N/A #N/A #N/A #N/A 0.00 #N/A #N/A #N/A #N/A #N/A #N/A #N/A 0.00 #N/A #N/A #N/A #N/A #N/A #N/A #N/A 0.00 #N/A #N/A #N/A #N/A #N/A #N/A #N/A 0.00 #N/A #N/A #N/A #N/A #N/A #N/A #N/A 0.00 #N/A #N/A #N/A #N/A #N/A #N/A #N/A 0.00 #N/A #N/A #N/A #N/A #N/A #N/A #N/A 0.00 #N/A #N/A #N/A #N/A #N/A #N/A #N/A 0.00 #N/A #N/A #N/A #N/A #N/A #N/A #N/A 0.00 #N/A #N/A #N/A #N/A #N/A #N/A #N/A 0.00 #N/A #N/A #N/A #N/A #N/A #N/A #N/A 0.00 #N/A #N/A #N/A #N/A #N/A #N/A #N/A 0.00 #N/A #N/A #N/A #N/A #N/A #N/A #N/A 0.00 #N/A #N/A #N/A #N/A #N/A #N/A #N/A 0.00 #N/A #N/A #N/A #N/A #N/A #N/A #N/A 0.00 #N/A #N/A #N/A #N/A #N/A #N/A #N/A 0.00 #N/A #N/A #N/A #N/A #N/A #N/A #N/A 0.00 #N/A #N/A #N/A #N/A #N/A #N/A #N/A 0.00 #N/A #N/A #N/A #N/A #N/A #N/A #N/A 0.00 #N/A #N/A #N/A #N/A #N/A #N/A #N/A 0.00 #N/A #N/A #N/A #N/A #N/A #N/A #N/A 0.00 #N/A Routing 3: Single Stage - Water flows through WQCV plate and #1 horizontal opening into #1 vertical opening. This flow will be applied to culvert sheet (#2 vertical & horizontal openings is not used). STAGE-DISCHARGE SIZING OF THE WEIRS AND ORIFICES (INLET CONTROL) Tract II Bloom Filing One Site Current Routing Order is #3 W.S. EL. WQ W.S. EL. Minor W.S. EL. Major WQ H1 H2 V1 V2 Routing Order #1 (Standard) V1 W.S. EL. WQ W.S. EL. Design Storm WQ H1 Routing Order #3 (Single Stage)Routing Order #4 V2 V1 H1 WQ W.S. EL. Major W.S. EL. Minor W.S. EL. WQ W.S. EL. Emergency Spillway Emergency Overflow into Pipe- H2 V2 H1 WQ W.S. EL. Major W.S. EL. Minor W.S. EL. WQ V1 Routing Order #2 Bloom WQ UD-Detention_2.35.xls, Outlet 12/19/2023, 2:09 PM D-7 Project: Basin ID: Tract II Bloom Filing One Site STAGE-DISCHARGE SIZING OF THE WEIRS AND ORIFICES (INLET CONTROL) 0 1000 2000 3000 4000 5000 6000 0 0.2 0.4 0.6 0.8 1 1.2 St a g e ( f e e t , e l e v . ) Discharge (cfs) STAGE-DISCHARGE CURVE FOR THE OUTLET STRUCTURE Bloom WQ UD-Detention_2.35.xls, Outlet 12/19/2023, 2:09 PM D-8 Project: Basin ID: Status:Sheet Contains Warnings. See Culvert_ErrorList Range Design Information (Input): Circular Culvert: Barrel Diameter in Inches D = 12 in. Circular Culvert: Inlet Edge Type (choose from pull-down list) Grooved End with Headwall OR: Box Culvert: Barrel Height (Rise) in Feet Height (Rise) = ft. Box Culvert: Barrel Width (Span) in Feet Width (Span) = ft. Box Culvert: Inlet Edge Type (choose from pull-down list)Square Edge w/ 90-15 deg. Flared Wingwall Number of Barrels No = 1 Inlet Elevation at Culvert Invert Ielev =4925.50 ft. elev. Outlet Elevation at Culvert Invert Oelev =4925.00 ft. elev. Culvert Length in Feet L = 60.0 ft. Manning's Roughness n = 0.0120 Bend Loss Coefficient Kb =0.00 Exit Loss Coefficient Kx =1.00 Design Information (calculated): Entrance Loss Coefficient Ke = Friction Loss Coefficient Kf = Sum of All Loss Coefficients Ks = Orifice Inlet Condition Coefficient Cd = Minimum Energy Condition Coefficient KElow = Calculations of Culvert Capacity (output): Water Surface Tailwater Culvert Culvert Flowrate Controlling Inlet Elevation Surface Inlet-Control Outlet-Control Into Culvert Culvert Equation From Sheet Elevation Flowrate Flowrate From Sheet Flowrate Used "Basin"ft cfs cfs "Outlet"cfs (ft., linked)(input if known)(output) (output) (cfs, linked) (output) (output) 4925.50 4925.50 0.00 4926.00 4925.50 0.01 4926.50 4925.50 0.02 4927.00 4925.50 0.47 4927.50 4925.50 0.59 4928.00 4925.50 0.68 4928.50 4925.50 0.77 4929.00 0.84 4929.50 0.91 4930.00 0.97 4930.50 1.03 4931.00 1.09 0.00 #N/A 0.00 #N/A 0.00 #N/A 0.00 #N/A 0.00 #N/A 0.00 #N/A 0.00 #N/A 0.00 #N/A 0.00 #N/A 0.00 #N/A 0.00 #N/A 0.00 #N/A 0.00 #N/A 0.00 #N/A 0.00 #N/A 0.00 #N/A 0.00 #N/A 0.00 #N/A 0.00 #N/A 0.00 #N/A 0.00 #N/A 0.00 #N/A 0.00 #N/A 0.00 #N/A 0.00 #N/A 0.00 #N/A 0.00 #N/A 0.00 #N/A 0.00 #N/A 0.00 #N/A 0.00 #N/A 0.00 #N/A STAGE-DISCHARGE SIZING OF THE OUTLET CULVERT (INLET vs. OUTLET CONTROL WITH TAILWATER EFFECTS) Tract II Bloom Filing One Site Bloom WQ UD-Detention_2.35.xls, Culvert 12/19/2023, 2:09 PM D-9 Project: Basin ID: STAGE-DISCHARGE SIZING OF THE OUTLET CULVERT (INLET vs. OUTLET CONTROL WITH TAILWATER EFFECTS) Tract II Bloom Filing One Site 0.00 1000.00 2000.00 3000.00 4000.00 5000.00 6000.00 0.00 10.00 20.00 30.00 40.00 50.00 St a g e ( f e e t , e l e v . ) Discharge (cfs) STAGE-DISCHARGE CURVE FOR THE FINAL OUTLET PIPE CULVERT Bloom WQ UD-Detention_2.35.xls, Culvert 12/19/2023, 2:09 PM D-10 Project: Basin ID: 75.96 4.00000 Design Information (input): Bottom Length of Weir L = 40.00 feet Angle of Side Slope Weir Angle = 75.96 degrees Elev. for Weir Crest EL. Crest = 4,930.00 feet Coef. for Rectangular Weir Cw = 0.60 Coef. for Trapezoidal Weir Ct = 3.00 Calculation of Spillway Capacity (output): Water Rect. Triangle Total Total Surface Weir Weir Spillway Pond Elevation Flowrate Flowrate Release Release ft. cfs cfs cfs cfs (linked) (output) (output) (output) (output) 4925.50 0.00 0.00 0.00 0.00 4926.00 0.00 0.00 0.00 0.00 4926.50 0.00 0.00 0.00 0.00 4927.00 0.00 0.00 0.00 0.00 4927.50 0.00 0.00 0.00 0.00 4928.00 0.00 0.00 0.00 0.00 4928.50 0.00 0.00 0.00 0.00 4929.00 0.00 0.00 0.00 0.00 4929.50 0.00 0.00 0.00 0.00 4930.00 0.00 0.00 0.00 0.00 4930.50 8.49 2.12 10.61 10.61 4931.00 24.00 12.00 36.00 36.00 #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A STAGE-DISCHARGE SIZING OF THE SPILLWAY Tract II Bloom Filing One Site Bloom WQ UD-Detention_2.35.xls, Spillway 12/19/2023, 2:10 PM D-11 Project: Basin ID: STAGE-DISCHARGE SIZING OF THE SPILLWAY Tract II Bloom Filing One Site 0 0.5 1 1.5 2 2.5 3 4740.3 4790.3 4840.3 4890.3 4940.3 4990.3 0 5 10 15 20 25 30 35 40 Storage (Acre-Feet) St a g e ( f e e t , e l e v . ) Pond Discharge (cfs) STAGE-STORAGE-DISCHARGE CURVES FOR THE POND TOTAL DISCHARGE SPILLWAY DISCHARGE POND STORAGE Bloom WQ UD-Detention_2.35.xls, Spillway 12/19/2023, 2:10 PM D-12 Channel Report Hydraflow Express Extension for Autodesk® Civil 3D® by Autodesk, Inc. Tuesday, Dec 19 2023 Lake Canal Cross-Section Trapezoidal Bottom Width (ft) = 8.00 Side Slopes (z:1) = 1.50, 1.50 Total Depth (ft) = 10.00 Invert Elev (ft) = 4922.00 Slope (%) = 0.10 N-Value = 0.015 Calculations Compute by: Known Q Known Q (cfs) = 158.00 Highlighted Depth (ft) = 2.75 Q (cfs) = 158.00 Area (sqft) = 33.34 Velocity (ft/s) = 4.74 Wetted Perim (ft) = 17.92 Crit Depth, Yc (ft) = 2.02 Top Width (ft) = 16.25 EGL (ft) = 3.10 0 5 10 15 20 25 30 35 40 45 50 Elev (ft)Depth (ft)Section 4920.00 -2.00 4922.00 0.00 4924.00 2.00 4926.00 4.00 4928.00 6.00 4930.00 8.00 4932.00 10.00 4934.00 12.00 Reach (ft) D-13 i2 Consultants, Inc. Excerpts from Previous Reports Bloom Filing 1 Final Drainage Report Galloway & Company, Inc. Page 1 of 29 PREPARED FOR: Hartford Homes, LLC 4801 Goodman St. Timnath, CO 80547 PREPARED BY: Galloway & Company, Inc. 5265 Ronald Reagan Blvd., Suite 210 Johnstown, CO 80534 Contact: James Prelog, PE DATE: March 30, 2022 Revised June 1, 2022 Revised July 13, 2022 Revised August 16, 2022 Revised November 14, 2022 - Record BLOOM FILING 1 Fort Collins, CO FINAL DRAINAGE REPORT City of Fort Collins Approved Plans Approved by: Date: o e8 oo ' sN m o o l a o = I I I I I I I I I I I I I I 3 r, o ag o s y a2 g w. o ao = w p ti , o do o Lj j ot i oy wo s B I I I I I o d'y _ 3N O NI l I W0 0 1 9 U w SN b ' ld 1N 3 W d O l 3 A 3 4 l H N l a i i i i i i i i i i i i i i 2 B s R ff v. y w ' ; a s i I I g _ Eo 1 a$ a e i $ I m a , I NE a < o a i s ws w ' = a o Q as o = e o= o" LL w o B 6 s aw ` . ss i I" 3 a` a_ o s _ g E r= n 0 3$ 3g a g: a w 3` s a 0 8 w` . . . E LL g y C3 ' U g' ' ga y g ; Y . , , _ ed a - ` 3 ' ' 3' = ` so ° i g s Q% " s a E _ as ` ' o g 6 a e a ; , u o s- . ss = a a gc g e _ ff ' = a LL = - wg ' p e ` s o a s s a E S Q sa _ ee _ ff s a$ ; r . , , l l' Ol 13 3 H S 33 S - 3N I l H 1H W r, . . _ . . _ . _ . . . . \ . . _ . . _ . , \ _ . o o . s' ; , ' ' i U` / , RI I 1 / I I fw / . I I I i . I ai " 2 I I s r - @L NR Y _ W I . . , 1 I' / w€ I a i I i 1 p a I . , I r< 1 3 PR I te x i y= . a. : _ ' sa - - _ _ _ ' r I I I - _ _ _ . . . _ _ i i a I i I C i ii I - ' I I I M ; $ ' i' j I i r , o x o f! m P j o w' V I' ' I I w n I @ I k I I I 2N w: L=i I I I I w w I N I , I I Z I I Ii e f i I j , I i I i / , M i I r, I r r- - - - - - - - II I I o e8 oo ' sN m o o l a o = I I I I I I I I I I I I I I 3 r, o ag s y a2 g w. o ao = w p ti , o do o Lj j ot i oy wo s B I I I I I o d'y _ 3N O NI l I W0 0 1 9 U w SN b ' ld 1N 3 W d O l 3 A 3 4 l H N l a i i i i i i i i i i i i i i w s_ a a e I 8$ g ' Eo 1 a e i $ I m a , I NE a o a i s ws w ' = a o Q as o = e o= o" LL w o B 6 s aw ` . ss i I" 3 a` a_ o s _ g o ga g' : a w a` s a = o a w- w" gw _ e= i> ga y - y; Y „ V - e a ' ' = 3 ' 0' - 3€ ip o g o ° i g s Q% " s a E : ag . ` - _ _ e ' o g 6 a e a ; , u o s- . ss = a a gc g e _ ff ' = a LL = - wg ' ' pm o= s s a8 a 3 a a s$ _ ee s g$ r . , . . . 6' 06 13 3 H S 33 S - 3N I l H 1d W i k\ ` I : . , . } il I' I1 1 3 I I i I i I w 1 i rt, I I II I o I i i j I, I 1; L. H E I r 1- - I h J , I 9 l ' i a i i ! ii o i U wW. i, i w, i , Z i I 1- a , , / i" @ II I o r o I I I I I j j II I I I I I I jI I i2 Consultants, Inc. Charts and Figures FORT COLLINS STORMWATER CRITERIA MANUAL Hydrology Standards (Ch. 5) 3.0 Rational Method 3.2 Runoff Coefficients Page 5 Table 3.2-2. Surface Type - Runoff Coefficients Surface Type Runoff Coefficients Hardscape or Hard Surface Asphalt, Concrete 0.95 Rooftop 0.95 Recycled Asphalt 0.80 Gravel 0.50 Pavers 0.50 Landscape or Pervious Surface Lawns, Sandy Soil, Flat Slope < 2% 0.10 Lawns, Sandy Soil, Avg Slope 2-7% 0.15 Lawns, Sandy Soil, Steep Slope >7% 0.20 Lawns, Clayey Soil, Flat Slope < 2% 0.20 Lawns, Clayey Soil, Avg Slope 2-7% 0.25 Lawns, Clayey Soil, Steep Slope >7% 0.35 3.2.1 Composite Runoff Coefficients Drainage sub-basins are frequently composed of land that has multiple surface types or zoning classifications. In such cases a composite runoff coefficient must be calculated for any given drainage sub-basin. The composite runoff coefficient is obtained using the following formula: ( ) t n i ii A xAC C ∑ ==1 Equation 5-2 Where: C = Composite Runoff Coefficient Ci = Runoff Coefficient for Specific Area (Ai), dimensionless Ai = Area of Surface with Runoff Coefficient of Ci, acres or square feet n = Number of different surfaces to be considered At = Total Area over which C is applicable, acres or square feet 3.2.2 Runoff Coefficient Frequency Adjustment Factor The runoff coefficients provided in Table 3.2-1 and Table 3.2-2 are appropriate for use with the 2-year storm event. For any analysis of storms with higher intensities, an adjustment of the runoff coefficient is required due to the lessening amount of infiltration, depression retention, evapotranspiration and other losses that have a proportionally smaller effect on high-intensity storm runoff. This adjustment is F-1 FORT COLLINS STORMWATER CRITERIA MANUAL Hydrology Standards (Ch. 5) 3.0 Rational Method 3.3 Time of Concentration Page 6 applied to the composite runoff coefficient. These frequency adjustment factors, Cf, are found in Table 3.2-3. Table 3.2-3. Frequency Adjustment Factors Storm Return Period (years) Frequency Adjustment Factor (Cf) 2, 5, 10 1.00 25 1.10 50 1.20 100 1.25 3.3 Time of Concentration 3.3.1 Overall Equation The next step to approximate runoff using the Rational Method is to estimate the Time of Concentration, Tc, or the time for water to flow from the most remote part of the drainage sub-basin to the design point under consideration. The Time of Concentration is represented by the following equation: 𝐓𝐓𝐜𝐜=𝐓𝐓𝐢𝐢+𝐓𝐓𝐭𝐭 Equation 5-3 Where: Tc = Total Time of Concentration, minutes Ti = Initial or Overland Flow Time of Concentration, minutes Tt = Channelized Flow in Swale, Gutter or Pipe, minutes 3.3.2 Overland Flow Time Overland flow, Ti, can be determined by the following equation: 𝐓𝐓𝐢𝐢=𝟏𝟏.𝟖𝟖𝟖𝟖(𝟏𝟏.𝟏𝟏−𝐂𝐂𝐂𝐂𝐂𝐂𝐟𝐟)√𝐋𝐋√𝐒𝐒𝟑𝟑 Equation 3.3-2 Where: C = Runoff Coefficient, dimensionless Cf = Frequency Adjustment Factor, dimensionless L = Length of Overland Flow, feet S = Slope, percent CXCF PRODUCT OF CXCF CANNOT EXCEED THE VALUE OF 1 OVERLAND FLOW LENGTH L=200’ MAX IN DEVELOPED AREAS L=500’ MAX IN UNDEVELOPED AREAS F-2 FORT COLLINS STORMWATER CRITERIA MANUAL Hydrology Standards (Ch. 5) 3.0 Rational Method 3.4 Intensity-Duration-Frequency Curves for Rational Method Page 8 Table 3.4-1. IDF Table for Rational Method Duration (min) Intensity 2-year (in/hr) Intensity 10-year (in/hr) Intensity 100-year (in/hr) Duration (min) Intensity 2-year (in/hr) Intensity 10-year (in/hr) Intensity 100-year (in/hr) 5 2.85 4.87 9.95 39 1.09 1.86 3.8 6 2.67 4.56 9.31 40 1.07 1.83 3.74 7 2.52 4.31 8.80 41 1.05 1.80 3.68 8 2.40 4.10 8.38 42 1.04 1.77 3.62 9 2.30 3.93 8.03 43 1.02 1.74 3.56 10 2.21 3.78 7.72 44 1.01 1.72 3.51 11 2.13 3.63 7.42 45 0.99 1.69 3.46 12 2.05 3.50 7.16 46 0.98 1.67 3.41 13 1.98 3.39 6.92 47 0.96 1.64 3.36 14 1.92 3.29 6.71 48 0.95 1.62 3.31 15 1.87 3.19 6.52 49 0.94 1.6 3.27 16 1.81 3.08 6.30 50 0.92 1.58 3.23 17 1.75 2.99 6.10 51 0.91 1.56 3.18 18 1.70 2.90 5.92 52 0.9 1.54 3.14 19 1.65 2.82 5.75 53 0.89 1.52 3.10 20 1.61 2.74 5.60 54 0.88 1.50 3.07 21 1.56 2.67 5.46 55 0.87 1.48 3.03 22 1.53 2.61 5.32 56 0.86 1.47 2.99 23 1.49 2.55 5.20 57 0.85 1.45 2.96 24 1.46 2.49 5.09 58 0.84 1.43 2.92 25 1.43 2.44 4.98 59 0.83 1.42 2.89 26 1.4 2.39 4.87 60 0.82 1.4 2.86 27 1.37 2.34 4.78 65 0.78 1.32 2.71 28 1.34 2.29 4.69 70 0.73 1.25 2.59 29 1.32 2.25 4.60 75 0.70 1.19 2.48 30 1.30 2.21 4.52 80 0.66 1.14 2.38 31 1.27 2.16 4.42 85 0.64 1.09 2.29 32 1.24 2.12 4.33 90 0.61 1.05 2.21 33 1.22 2.08 4.24 95 0.58 1.01 2.13 34 1.19 2.04 4.16 100 0.56 0.97 2.06 35 1.17 2.00 4.08 105 0.54 0.94 2.00 36 1.15 1.96 4.01 110 0.52 0.91 1.94 37 1.16 1.93 3.93 115 0.51 0.88 1.88 38 1.11 1.89 3.87 120 0.49 0.86 1.84 F-3 FORT COLLINS STORMWATER CRITERIA MANUAL Hydrology Standards (Ch. 5) 3.0 Rational Method 3.4 Intensity-Duration-Frequency Curves for Rational Method Page 9 Figure 3.4-1. Rainfall IDF Curve – Fort Collins F-4 FORT COLLINS STORMWATER CRITERIA MANUAL Hydrology Standards (Ch. 5) 4.0 SWMM 4.1 Input Parameters Page 11 Table 4.1-2. Land Use - Percent Impervious Land Use Percent Impervious (%) Residential Urban Estate 30 Low Density 50 Medium Density 70 High Density 90 Commercial Commercial 80 Industrial 90 Undeveloped Open Lands, Transition 20 Greenbelts, Agriculture 2 Offsite Flow Analysis (when Land Use not defined) 45 Reference: For further guidance regarding zoning classifications, refer to the Land Use Code, Article 4. For Final Plan (FP) submittals, impervious values must be based on the proposed land surface types. Refer to Table 4.1-3 for recommended percent impervious values. Table 4.1-3. Surface Type – Percent Impervious Surface Type Percent Impervious (%) Hardscape or Hard Surface Asphalt, Concrete 100 Rooftop 90 Recycled Asphalt 80 Gravel 40 Pavers 40 Landscape or Pervious Surface Playgrounds 25 Lawns, Sandy soil 2 Lawns, Clayey soil 2 F-5 Project:Disturbed Acres:2.00 EROSION CONTROL BMPs Units Estimated Quantity Unit Price Total Price L.F.1150 $5.00 $5,750.00 L.F.100 $5.00 $500.00 EA 1 $1,000.00 $1,000.00 EA 1 $200.00 $200.00 EA 1 $1,500.00 $1,500.00 L.F.50 $5.00 $250.00 Sub-Total:$9,200.00 1.5 x Sub-Total:$13,800.00 Amount of security:$13,800.00 Total Acres x Price/acre:$4,000.00 $2,000.00 Sub-Total: $4,000.00 1.5 x Sub-Total:$6,000.00 Amount to Re-seed:$6,000.00 Minimum escrow amount:$3,000.00 Erosion Control Escrow:$13,800.00 Erosion and Sediment Control Escrow/Security Calculation for The City of Fort Collins BMP Amount Sediment Control Log (SCL) Vehicle Tracking Control Mat (VTC) Rock Sock (RS) Reseeding Amount Silt Fence (SF) Miniumum Escrow Amount Tract II, Bloom Filing One Unit Price of Seeding per acre: “The amount of the security must be based on one and one-half times the estimate of the cost to install the approved measures, or one and one-half times the cost to re-vegetate the disturbed land to dry land grasses based upon unit cost determined by the City's Annual Revegetation and Stabilization Bid, whichever is greater. In no instance, will the amount of security be less than one thousand five hundred dollars ($1,500) for residential development or three thousand dollars ($3,000) for commercial development” Inlet Protection (IP) Concrete Washout (CWA) Final Escrow Amount 12/19/2023 1:20 PM C:\Users\troy\Dropbox\I2\Projects\1061-3 Bloom\Documents\Drainage\Bloom_EC_Escrow.xls F-6 PARCEL NO. 8708400064 OWNER: WILLIAM HOUSE ET AL PARCEL NO. 8708400057 OWNER: WILLIAM HOUSE ET AL LOT 1 AMENDED PLAT L 1-8, TRACT B & DOZIER DR PARCEL NO. 8708400034 OWNER: WILLIAM HOUSE ET AL PARCEL NO. 8709000008 OWNER: LUDIQUE CHAT, LLC P A R C E L N O . 8 7 0 9 0 0 0 9 4 0 O W N E R : L A K E C A N A L IR R I G A T I O N C O M P A N Y PARCEL NO. 8709307007 OWNER: MULBERRY SF LLC L A K E C A N A L DE L O Z I E R D R PROPOSED DETENTION POND EAST MULBERRY (HWY 14) FRONTAGE ROAD PROPOSED DETENTION POND PROPOSED DETENTION POND TRACT II BLOOM FILING ONE BLOOM FILING FIVE LOT 1 LOT 2 LOT 4 LOT 3 SHEET OF SHEETS T R A C T I I , B L O O M F I L I N G O N E C I T Y O F F O R T C O L L I N S , C O U N T Y O F L A R I M E R , S T A T E O F C O L O R A D O 15 U T I L I T Y P L A N S Know what's below. before you dig.Call R PRELIMINARY NOT FOR CONSTRUCTION 12/20/2023 LI D E X H I B I T LID-1 i2 LEGEND OF SYMBOLS – ’. SURVEY NOTES C: \ U s e r s \ t r o y \ D r o p b o x \ I 2 \ P r o j e c t s \ 1 0 6 1 - 3 B l o o m \ D W G \ S h e e t s \ B l o o m _ L I D . D W G , 1 2 / 1 9 / 2 0 2 3 2 : 1 6 : 0 8 P M , D W G T o P D F . p c 3 PARCEL NO. 8708400064 OWNER: WILLIAM HOUSE ET AL PARCEL NO. 8708400057 OWNER: WILLIAM HOUSE ET AL LOT 1 AMENDED PLAT L 1-8, TRACT B & DOZIER DR PARCEL NO. 8708400034 OWNER: WILLIAM HOUSE ET AL PARCEL NO. 8709000008 OWNER: LUDIQUE CHAT, LLC P A R C E L N O . 8 7 0 9 0 0 0 9 4 0 O W N E R : L A K E C A N A L IR R I G A T I O N C O M P A N Y PARCEL NO. 8709307007 OWNER: MULBERRY SF LLC L A K E C A N A L DE L O Z I E R D R PROPOSED DETENTION POND EAST MULBERRY (HWY 14) FRONTAGE ROAD PROPOSED DETENTION POND PROPOSED DETENTION POND BLOOM FILING FIVE LOT 1 LOT 2 LOT 4 LOT 3 OUTLOT A SHEET OF SHEETS T R A C T I I , B L O O M F I L I N G O N E C I T Y O F F O R T C O L L I N S , C O U N T Y O F L A R I M E R , S T A T E O F C O L O R A D O 15 U T I L I T Y P L A N S Know what's below. before you dig.Call R PRELIMINARY NOT FOR CONSTRUCTION 12/20/2023 OV E R A L L D R A I N A G E P L A N C-9 9 i2 LEGEND OF SYMBOLS BASIN RUNOFF SUMMARY DETENTION SUMMARY – ’. SURVEY NOTES C: \ U s e r s \ t r o y \ D r o p b o x \ I 2 \ P r o j e c t s \ 1 0 6 1 - 3 B l o o m \ D W G \ S h e e t s \ B l o o m _ D R . D W G , 1 2 / 1 9 / 2 0 2 3 1 : 2 3 : 2 6 P M , _ A u t o C A D P D F ( G e n e r a l D o c u m e n t a t i o n ) . p c 3 PARCEL NO. 8708400064 OWNER: WILLIAM HOUSE ET AL PARCEL NO. 8708400057 OWNER: WILLIAM HOUSE ET AL LOT 1 AMENDED PLAT L 1-8, TRACT B & DOZIER DR PARCEL NO. 8708400034 OWNER: WILLIAM HOUSE ET AL PARCEL NO. 8709000008 OWNER: LUDIQUE CHAT, LLC P A R C E L N O . 8 7 0 9 0 0 0 9 4 0 O W N E R : L A K E C A N A L IR R I G A T I O N C O M P A N Y PARCEL NO. 8709307007 OWNER: MULBERRY SF LLC L A K E C A N A L DE L O Z I E R D R PROPOSED DETENTION POND EAST MULBERRY (HWY 14) FRONTAGE ROAD PROPOSED DETENTION POND PROPOSED DETENTION POND INTERIM INTERIM INITIAL INITIAL INTERIM INTERIM INTERIMINTERIM INTERIM INTERIM INTERIM INTERIM INITIAL INITIAL INITIAL INITIAL INITIAL INITIAL INITIAL INTERIM INTERIM INTERIM BLOOM FILING FIVE LOT 1 LOT 2 LOT 4LOT 3 OUTLOT A SHEET OF SHEETS T R A C T I I , B L O O M F I L I N G O N E C I T Y O F F O R T C O L L I N S , C O U N T Y O F L A R I M E R , S T A T E O F C O L O R A D O 15 U T I L I T Y P L A N S Know what's below. before you dig.Call R PRELIMINARY NOT FOR CONSTRUCTION 12/20/2023 SE D I M E N T & E R O S I O N C O N T R O L P L A N C-10 10 i2 LEGEND OF SYMBOLS TENTATIVE CONSTRUCTION SCHEDULE NOTES EROSON CONTROL TABLE – ’. SURVEY NOTES C: \ U s e r s \ t r o y \ D r o p b o x \ I 2 \ P r o j e c t s \ 1 0 6 1 - 3 B l o o m \ D W G \ S h e e t s \ B l o o m _ E C . D W G , 1 2 / 1 9 / 2 0 2 3 1 : 2 3 : 3 6 P M , _ A u t o C A D P D F ( G e n e r a l D o c u m e n t a t i o n ) . p c 3 DE T A I L S H E E T 1 C-11 11 SHEET OF SHEETS T R A C T I I , B L O O M F I L I N G O N E C I T Y O F F O R T C O L L I N S , C O U N T Y O F L A R I M E R , S T A T E O F C O L O R A D O 15 U T I L I T Y P L A N S Know what's below. before you dig.Call R PRELIMINARY NOT FOR CONSTRUCTION 12/20/2023 C: \ U s e r s \ t r o y \ D r o p b o x \ I 2 \ P r o j e c t s \ 1 0 6 1 - 3 B l o o m \ D W G \ S h e e t s \ B l o o m _ D T . d w g , 1 2 / 1 9 / 2 0 2 3 1 : 2 3 : 4 4 P M , _ A u t o C A D P D F ( G e n e r a l D o c u m e n t a t i o n ) . p c 3 DE T A I L S H E E T 2 C-12 12 SHEET OF SHEETS T R A C T I I , B L O O M F I L I N G O N E C I T Y O F F O R T C O L L I N S , C O U N T Y O F L A R I M E R , S T A T E O F C O L O R A D O 15 U T I L I T Y P L A N S Know what's below. before you dig.Call R PRELIMINARY NOT FOR CONSTRUCTION 12/20/2023 SPILL CURB & GUTTER 6" 6" 12" 6" 1" 2" R 1 1/2" R 18" CATCH CURB & GUTTER C: \ U s e r s \ t r o y \ D r o p b o x \ I 2 \ P r o j e c t s \ 1 0 6 1 - 3 B l o o m \ D W G \ S h e e t s \ B l o o m _ D T . d w g , 1 2 / 1 9 / 2 0 2 3 1 : 2 3 : 5 4 P M , _ A u t o C A D P D F ( G e n e r a l D o c u m e n t a t i o n ) . p c 3 100-Year Overflow Spillway Elev: 4930.0 3' Min. 2 - #5 Bars 2 - #5 Bars 3" Min. Clearance 8" Min. Thickness (See Note) 5'5' 3" Min. Clearance 4'4' 2.5' High water during overflow of entire 100-year peak runoff. Elev: 4930.5 40' Section A - A Concrete Weir Overflow Structure Detail SP-01 Spillway Detail Note: Construct concrete cutoff wall at upstream end of the spillway as shown in detail. Cutoff wall shall extend a minimum of 5 feet past the opening of the top of spillway on each side of the spillway as shown in detail. Cutoff walls shall be a minimum of 8" thick and minimum 3' deep. Walls shall use 3000 PSI. 5' Wide Berm(MIN.) 100-YEAR WSEL ELEV: 4929.50 Concrete weir structure centered in berm Proposed top of pond Crest Inv: 4931.0 Emergency overflow weir Crest Inv: 4930.00 Place 18" Type L Riprap on geotextile fabric (Mirafi FW 140 or equal) as, per Urban Drainage Design guidelines extend to concrete weir structure Top of Pond Elev: 4931.00 High water during overflow of entire 100-year peak runoff. Elev: 4930.5 12" Type II Bedding Compacted Earth 95% Standard Proctor Density 8" Min. Thickness (See Note) 1' Min. Freeboard DE T A I L S H E E T 5 C-15 15 SHEET OF SHEETS T R A C T I I , B L O O M F I L I N G O N E C I T Y O F F O R T C O L L I N S , C O U N T Y O F L A R I M E R , S T A T E O F C O L O R A D O 15 U T I L I T Y P L A N S Know what's below. before you dig.Call R PRELIMINARY NOT FOR CONSTRUCTION 12/20/2023 C: \ U s e r s \ t r o y \ D r o p b o x \ I 2 \ P r o j e c t s \ 1 0 6 1 - 3 B l o o m \ D W G \ S h e e t s \ B l o o m _ D T . d w g , 1 2 / 1 9 / 2 0 2 3 1 : 2 4 : 1 8 P M , _ A u t o C A D P D F ( G e n e r a l D o c u m e n t a t i o n ) . p c 3