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Home My WebLink AboutDrainage Reports - 03/26/2021FINAL DRAINAGE REPORT 19 OLD TOWN SQUARE #238 | FORT COLLINS, CO 80524 | 970-530-4044 | www.unitedcivil.com P RECISION T ECHNOLOGY Harmony Technology Park Fifth Filing Lot 2 Fort Collins, CO Prepared for: Precision Technology LLC 224 Canyon Avenue Unit 624 Fort Collins, CO 80521 Date: March 23 rd , 2021 City of Fort Collins Approved Plans Approved by: Date: Wes Lamarque 3/26/2021 F INAL D RAINAGE R EPORT P RECISION T ECHNOLOGY F ORT C OLLINS , CO i U20015_Drainage Report City of Fort Collins Stormwater Utility 700 Wood Street Fort Collins, Colorado 80521 RE: Precision Technology Final Drainage Report Fort Collins, Colorado Project Number: U20015 Dear Staff: United Civil Design Group, LLC. is pleased to submit this Final Drainage Report for the Precision Technology site in Fort Collins, Colorado. In general, this report serves to document the stormwater impacts associated with the proposed improvements related to the existing site. We understand that review by the City of Fort Collins is to assure general compliance with standardized criteria contained in the Fort Collins Stormwater Criteria Manual (FCSCM). This report was prepared in compliance with technical criteria set forth in both the Urban Drainage and Flood Control District (UDFCD) Urban Storm Drainage Criteria Manual and the Fort Collins Stormwater Criteria Manual. If you should have any questions or comments as you review this report, please feel free to contact us at your convenience. Sincerely, United Civil Design Group, LLC Nate Stroud, PE, LSIT Professional Engineer II 3/23/2021 F INAL D RAINAGE R EPORT P RECISION T ECHNOLOGY F ORT C OLLINS , CO ii U20015_Drainage Report TABLE OF CONTENTS I. General Location and Description ................................................................................................................ 1 A. Location and Project Description .............................................................................................. 1 B. Description of Property ............................................................................................................ 2 C. Floodplains .............................................................................................................................. 2 II. Drainage Basins and Sub-Basins ................................................................................................................... 2 A. Major Basin Description ........................................................................................................... 2 B. Sub-Basin Description .............................................................................................................. 3 III. Drainage Design Criteria .............................................................................................................................. 3 A. Regulations .............................................................................................................................. 3 B. Directly Connected Impervious Area (DCIA) ............................................................................. 3 C. Hydrological Criteria ................................................................................................................ 3 D. Hydraulic Criteria ..................................................................................................................... 4 E. Modifications of Criteria .......................................................................................................... 4 IV. Drainage Facility Design............................................................................................................................... 4 A. General Concept ...................................................................................................................... 4 B. Specific Details ......................................................................................................................... 4 V. Erosion Control ............................................................................................................................................ 9 VI. Conclusions ................................................................................................................................................. 9 A. Compliance with Standards ...................................................................................................... 9 B. Drainage Concept .................................................................................................................... 9 C. Stormwater Quality ................................................................................................................ 10 VII. References ............................................................................................................................................. 11 APPENDICES APPENDIX A – Hydrology Calculations APPENDIX B – Hydraulic Calculations B.1 – Low Impact Development Calculations B.2 – Water Quality Calculations B.3 – Orifice Calculations (Reserved for Final Submittal) B.4 – Inlet Sizing Calculations (Reserved for Final Submittal) B.5 – Storm Pipe Calculations (Reserved for Final Submittal) B.6 – Curb Channel Calculations (Reserved for Final Submittal) B.7 – Weir Calculation (Reserved for Final Submittal) APPENDIX C – Referenced Materials APPENDIX D – Drainage Exhibits F INAL D RAINAGE R EPORT P RECISION T ECHNOLOGY F ORT C OLLINS , CO 1 U20015_Drainage Report I.GENERAL LOCATION AND DESCRIPTION A. LOCATION AND PROJECT DESCRIPTION The Precision Technology site (referred herein as “the site”) is the development of Lot 2, Harmony Technology Park Fifth Filing, located in the northwest quarter of Section 4, Township 6 North, Range 68 West of the 6th P.M., City of Fort Collins, Larimer County, Colorado. The property, consisting of approximately 4.65 acres, is located immediately north of Precision Drive, approximately 350-feet east of Technology Parkway and currently exists as vacant land in Harmony Technology Park. The proposed site improvements are limited to the 4.65 acres contained in Lot 2. The property is bounded by Precision Drive to the south, recently developed commercial businesses to the east and west, and an existing detention pond and park in the lot to the north. On site detention will not be provided with this site and was previously included in the Harmony Technology Park Stormwater Plan. A majority of the stormwater on the site currently drains southeast via sheet flow to existing drainage swales which is then collected by storm sewer infrastructure in Precision Drive and ultimately conveyed to a regional detention pond (Pond 110) at the intersection of Lady Moon Drive and Rock Creek Drive. There is also a small portion of the site that drains north via sheet flow to the existing Harmony Commons Pond which combines ponds 101, 301, and 600 from the previously mentioned master plan. Refer to the appendix for more information regarding the existing master plan and detention ponds. The proposed development of the site consists of the construction of a new commercial building with a 106,700-sf footprint. Associated with the building are proposed drive lanes, parking, utilities, and water quality features. On-site stormwater is largely designed to discharge to the existing stormwater infrastructure in Precision Drive. FIGURE 1:SITE VICINITY MAP In general, this report serves to provide an analysis of the drainage impacts associated with the development of site as it relates to existing and proposed drainage facilities on-site and to confirm that the development adheres to the requirements set forth in the master drainage study for the subdivision. Precision Dr Technology Pkwy Harmony Rd Zi e g l e r R d F INAL D RAINAGE R EPORT P RECISION T ECHNOLOGY F ORT C OLLINS , CO 2 U20015_Drainage Report B. DESCRIPTION OF PROPERTY The project site currently exists as a vacant lot with native grasses and an existing imperviousness of approximately 2%. In its existing (non-historic) condition, a minor portion of the site drains to the existing Harmony Commons Pond to the north and a majority of the site drains to the southeast corner of the site to an existing drainage swale where it is collected by existing storm sewer infrastructure and ultimately conveyed to another existing detention pond (Pond 110). Below are summaries of key components of the site in its existing conditions. Land Use - The site’s current land use is commercial. Ground Cover - The site is currently covered with native grasses and weeds. The weed/grass cover is good (ie., heavy or dense cover with nearly all ground surfaces protected by vegetation). Existing Topography – Historically, the site slopes in two general directions: northerly and southeasterly. A majority of the property drains to the southeast corner to existing storm sewer infrastructure located within Precision Drive, and a minor portion of the property sheet flows to the north to the existing Harmony Commons Pond. Grades – In general, the site is sloped southeasterly at approximately 0.5% to 2.0%; the southern portion of the site is sloped northerly at approximately 0.5% to 2.0%. There is also a large drainage swale at the southeast corner with slopes between 20% and 33%. Soil Type - The USDA’s Web Soil Survey shows that the site consists of a “Type C” soil. The Web Soil Survey indicates the site is comprised of Nunn Clay Loam (1 to 3% slopes). The on-site soils provide slow infiltration. Utilities – Both wet and dry utilities are present in the Precision Drive right-of-way to the south of the site. Water, storm, and sanitary mains are all present within Precision Drive while dry utilities including fiber, electric, and gas are present in the south portion of the right-of-way of Precision Drive. There also appears to be gas and electric lines near the southeast corner of the site in the adjacent property. Drainage Features and Storm Sewer – Existing storm sewer is present at the southeast corner of the site as well as within Precision Drive. Regional detention ponds also exist to the north and southeast which collect runoff from the site. C. FLOODPLAINS The proposed development is not in a FEMA designated or City Designated floodplain. According to the FEMA Flood Insurance Rate Map Panel, the site is zoned as an area outside of the 500-year floodplain. The FEMA FIRM Map is included in the appendix. II.DRAINAGE BASINS AND SUB-BASINS A. MAJOR BASIN DESCRIPTION The proposed development is located within the McClellands Basin as delineated on the City of Fort Collins Stormwater Basin Map. The site has also been previously accounted for in the Harmony Technology Park Site Master Plan Drainage Report as well as the Harmony Technology Third Filing Drainage Study, and the proposed development will be in conformance with both of these studies. FIGURE 2:FLOODPLAIN MAP F INAL D RAINAGE R EPORT P RECISION T ECHNOLOGY F ORT C OLLINS , CO 3 U20015_Drainage Report B. SUB-BASIN DESCRIPTION The existing site is located within sub-basin 180 of the HTP Third Filing and SWMM Basin 100 and 601 of the HTP Site Master Plan Drainage Report. The proposed site and project will be in conformance with both these reports. Improvements limited to a storm sewer extension was also provided from the HTP Fourth Filing project to the east of the site. In its developed condition, runoff from the site will largely be directed south and east to proposed bioretention ponds either via overland flow to surface improvements or via proposed storm sewer. A portion of the site on the north and south sides will drain to Precision Drive (south) and Harmony Commons Pond (north). Additionally, a minor portion of the site, largely all pervious area, will continue to drain offsite to the west to existing bioretention ponds on the neighboring property. III.DRAINAGE DESIGN CRITERIA A. REGULATIONS The design criteria for this study are directly from the City of Fort Collins Storm Drainage Design Criteria and Construction Standards Manual and the Urban Storm Drainage Criteria Manuals Volumes 2, and 3 (referred to herein as USDCM). B. DIRECTLY CONNECTED IMPERVIOUS AREA (DCIA) With the adoption of the USDCM, the City has also adopted the “Four Step Process” that is recommended in Volume 3 of the USDCM in selecting structural BMPs for the redeveloping urban areas. The following portions of this summary describe each step and how it has been utilized for this project: Step 1 – Employ Runoff Reduction Practices The objective of this step is to reduce runoff peaks and volumes and to employ the technique of “minimizing directly connected impervious areas” (MDCIA). This project accomplishes this by: Routing the roof and pavement flows through a bioretention facility and vegetated swales to increase time of concentration, promote infiltration and provide water quality. Step 2 – Provide Water Quality Capture Volume (WQCV) The objective of providing WQCV is to reduce the sediment load and other pollutants that exit the site. For this project WQCV is provided within the existing regional ponds offsite. The site will, however, provide additional water quality to meet the City’s Low Impact Development requirements through the use of onsite bioretention ponds. Step 3 – Stabilize Drainageways The site is not adjacent or near a major drainageway. Step 4 – Consider Need for Site Specific and Source Control BMPs Site specific and source control BMPs are generally considered for large industrial and commercial sites. The development of the site will include multiple site specific and source controls, including: Dedicated maintenance personnel providing landscape maintenance and snow and ice management. C. HYDROLOGICAL CRITERIA City of Fort Collins Rainfall Intensity-Duration-Frequency Curves, provided by Figure RA-16 of the Fort Collins Stormwater Criteria Manual, are utilized for all hydrologic computations related to the site in its existing/historic and proposed conditions. Since this site is relatively small and does not have complex drainage basins, the peak flow rates for design points have been calculated based on the Rational Method as described in the USDCM and the City of Fort Collins Stormwater Criteria Manual (FCSCM) with storm duration set equal to the time of concentration for each sub-basin. This method was used to analyze the developed runoff from the 10-year (minor) and the 100-year (major) storm events. The Rational Method is widely accepted F INAL D RAINAGE R EPORT P RECISION T ECHNOLOGY F ORT C OLLINS , CO 4 U20015_Drainage Report for drainage design involving small drainage areas (less than 160 acres) and short time of concentrations. Runoff coefficients are assumed based on impervious area and are given in the Appendices. D. HYDRAULIC CRITERIA The developed site will convey runoff to the proposed pond or underground treatment facility via swales, concrete channels, and pipes. The City of Fort Collins Stormwater Criteria Manual (FCSCM) and USDCM are referenced for all hydraulic calculations. In addition, the following computer programs are utilized: Storm Sewer Extension for AutoCAD Civil3D Hydraflow Express Extension for AutoCAD Civil3D UD-Inlet by UDFCD Drainage conveyance facility capacities proposed with the development project, including storm sewer, swales, and inlet capacities, are designed in accordance with criteria outlined in the FCSCM and/or the Urban Drainage and Flood Control District’s Urban Storm Drainage Criteria Manual (UDFCD). E. MODIFICATIONS OF CRITERIA No drainage variances or modifications of drainage criteria are proposed for this project. IV.DRAINAGE FACILITY DESIGN A. GENERAL CONCEPT Developed runoff is designed to be conveyed in a safe and effective manner via swales, concrete channels, and storm sewer systems/inlets. Stormwater is designed to be released to either the Harmony Commons Pond to the north or existing stormwater infrastructure in Precision Drive to the south and ultimately to Pond 110. Onsite runoff from the improved site will be conveyed to bioretention ponds at the northeast and southeast corners of the site. Additionally, a minor portion of the site, largely all pervious area, will continue to drain offsite to the west to existing bioretention ponds on the neighboring property. B. SPECIFIC DETAILS Hydrology As previously stated, hydrology from the developed site is designed to comply with criteria set forth in the City of Fort Collins Stormwater Criteria Manual. Referenced tables, charts, formulas, etc. are included in the appendices. The area, time of concentration, and runoff of each proposed sub-basin is summarized in Appendix A. The following information outlines the basin characteristics and drainage patterns for each basin. On-site Basins The following basins provide proposed drainage delineations for the site in its improved condition. Refer to Appendix A for hydrology computations and Appendix B for calculations related to Water Quality, Low Impact Development, and other hydraulic features. Basin A Sub-basins A1-A6 (see Drainage Plan attached) are generally located around eastern region of the site while sub-basins A1.1- A1.6 represent the east and north roof areas of the proposed building. These basins consist of roofs, concrete and asphalt paving and landscaping. Runoff within these basins is conveyed to the bioretention pond via downspouts, inlets, curb and gutter, and storm sewer. Runoff conveyed to the bioretention pond is discharged to the existing storm sewer stub from the property to the east which is conveyed to the storm sewer system within Precision Drive and ultimately south to regional detention Pond 110 at the intersection of Lady Moon Drive and Rock Creek Drive. F INAL D RAINAGE R EPORT P RECISION T ECHNOLOGY F ORT C OLLINS , CO 5 U20015_Drainage Report Basin B Sub-basins B1 and B1.1-B1.6 are generally located on the south side of the site. These sub-basins consist primarily of roofing, concrete walks, and landscaped area. Runoff within these basins is conveyed to Precision via sheet flow and storm sewer/roof drains. Basin C Basin C1 consists primarily of landscaped area and concrete pavement. Due to grading constraints, runoff developed within this basin drains off-site undetained via sheet flow and ultimately to the existing bioretention pond southwest of the site. The impervious area from Basin C1 is only 1,079 square feet (sidewalk) and no negative impacts are foreseen from this small amount of additional impervious area being drained to the existing rain garden at the southeast corner of the neighboring property to the east. Basin D Basin D1 consists primarily of landscaped area concrete pavement. Due to grading constraints, runoff developed within this basin drains off-site undetained to the west via sheet flow and ultimately to the existing bioretention pond northwest of the site. The impervious area from Basin D1 is approximately 1,943 square feet, of which 1,400 square feet is existing and is accounted for in the existing bioretention pond; therefore, the additional impervious area generated from Basin D1 is only 543 square feet. Due to the minor increase in impervious area, no negative impacts are foreseen for this additional impervious area draining to the existing rain garden at the northeast corner of the neighboring property to the west. Basin E Sub-basins E1-E2 are generally located around the north end of the site. These sub-basins consist of concrete and asphalt paving and landscaping. Runoff within these basins drains off-site undetained to the north via sheet flow and ultimately to the existing Harmony Commons Pond. Detention and Water Quality Water Quality Standard water quality is provided for this site in the offsite regional detention ponds, Harmony Common Ponds to the north and Pond 110 to the south of the site. The development of this site will require less water quality than originally assumed as per the Regional Detention Pond Comparison Chart on the following page. Additional water quality per the City’s Low Impact Development requirements will be provided on site. See Low Impact Development section later in the report. Detention Stormwater Detention is provided for this site in the offsite regional detention ponds, Harmony Common Ponds to the north and Pond 110 to the south of the site. The development of this site will result in an increase of impervious area headed south to Pond 110 but a small amount of detention will be provided on site in the bioretention to offset this area. The area draining to the north to Harmony Commons pond has less impervious area than originally intended and will require less stormwater detention than originally assumed, so no additional onsite detention is necessary for the north area. The HTP Site Master Plan Drainage Report allows for a developed impervious value of up to 80% for the proposed site with flow being released undetained from the site to Harmony Commons Pond (north) or Pond 110 (south). The HTP Site Master Plan Drainage Report had accounted for approximately 0.78 acres of area from the proposed site draining to the north to Harmony Commons Pond and 3.90 acres of area of the proposed site draining to the south to Pond 110. In its developed condition, 4.36 acres of the site will drain to the south and 0.49 acres of the site will drain to the north. Although more area and more impervious area will be draining to the south now, flow from the site will be constricted by the proposed outlet structure which will detain stormwater and help offset the additional impervious area going to Pond 110 as well as pipe capacities downstream of the site. Below is a comparison of the areas and imperviousness for the existing and proposed basins. F INAL D RAINAGE R EPORT P RECISION T ECHNOLOGY F ORT C OLLINS , CO 6 U20015_Drainage Report Regional Detention Pond Comparison Chart: Pond Previously Planned Area (sf) Proposed Area (sf) Master Plan Proposed Imperviousness (%) Developed Imperviousness (%) Master Plan Proposed Impervious Area (Assumes 80% Imperviousness) Proposed Impervious Area (sf) Harmony Commons (north) 34,035 21,358 80% 55.1% 27,228 11,567 Pond 110 (south) 169,668 189,796 80%72.7%135,734 137,981 The 100-year runoff from the HTP Site Master Plan Drainage Report for the developed site going to Pond 110 to the south was calculated to be 9.05 cfs/acre. This is based on the 32.9 acres with a flow of 297.7 cfs for SWMM Basin 100 of the HTP Site Master Plan Drainage Report. This correlates to a previously accounted release rate from the site of 35.25 cfs (3.90 acres * 9.05 cfs/acre). The proposed 100-year flows from the site draining to the south (Basins A, B, and C) are currently at 28.45 cfs and below the previously accounted for release rate in the HTP Master Plan Report. This also does not consider that Basin A flows will be reduced to 12 cfs in the 100-year storm through a restrictor plate in the outlet structure. With this restriction included, the flows from the site in the 100-year event from the site draining to Pond 110 will be 16.45 cfs. The 100-year runoff from the HTP Site Master Plan Drainage Report for the developed site going to the Harmony Commons pond to the north was calculated to be 9.08 cfs/acre. This is based on the 29.0 acres with a flow of 263.44 cfs for SWMM Basin 600 going to Pond 301 in the HTP Site Master Plan Drainage Report. This correlates to a previously accounted release rate from the site of 7.08 cfs (0.78 acres * 9.08 cfs/acre). The proposed 100-year flows from the site draining to the north (Basins D and E) are currently at 3.88 cfs and below the previously accounted for release rate in the HTP Master Plan Report. Refer to the existing drainage exhibit in the appendix for more information on these areas and how the existing basin line associates with the proposed site. Low Impact Development (LID) In December of 2015, Fort Collins City Council adopted the revised Low Impact Development (LID) policy and criteria which requires developments within City limits to meet certain enhanced stormwater treatment requirements in addition to more standard treatment techniques. The proposed development will be required to meet the newly adopted LID criteria which requires the following: - Treat no less than 75% of any newly added impervious area using one or a combination of LID techniques. - Treat no less than 50% of any newly added impervious area using one or a combination of LID techniques when at least 25% of any newly added pavement is provided with permeable pavement. The following measures are implemented with this proposed development: I.Bioretention Bioretention is designed to remove sediment and pollution from stormwater runoff via infiltration through an engineered sand media. This slows the conveyance rate of storm water runoff, reduces runoff and provides a flow path across a vegetated surface. A bioretention pond is proposed with the site improvements and will be utilized to convey and treat stormwater prior to release to Precision Drive. Bioretention Pond Sub-basins A1-A6 and A1.1-A1.6, with 121,393-sf of proposed impervious area, are designed to be conveyed to the bioretention pond located at the southeast corner of the site. The proposed impervious area treated through this bioretention pond includes proposed concrete and asphalt paving and roof areas in Basin A. Approximately 3,458- F INAL D RAINAGE R EPORT P RECISION T ECHNOLOGY F ORT C OLLINS , CO 7 U20015_Drainage Report cf of volume in the bioretention pond, with up to one foot of depth, is designed specifically for water quality. This volume slightly exceeds the required WQCV for Basin A (3,058-cf). Ponding above the initial one foot of depth will be conveyed through an outlet structure to existing downstream storm sewer infrastructure. Additionally, an orifice plat will be installed on the outlet structure to restrict flows from the site to 12 cfs in the 100-year event and allow an additional 0.93 feet of ponding above the bioretention volume area. The bioretention pond noted above treats approximately 75% of the proposed impervious area of the site. Refer to Appendix B for calculations. Below is a summary of the bioretention pond: Bottom of Pond Elevation Bioretention WSEL Bioretention Volume Required (cf) Bioretention Volume Provided (cf) Bioretention Pond 4908.00 4909.00 3,058 3,458 Outlet Structure A type C inlet will be used as an outlet structure at the southern end of the bioretention pond. Additionally, an orifice plate will be provided on the existing 24” storm pipe to restrict site flows in the 100-year even to 12 cfs. By reducing flows from the proposed site, pipe capacity for the overall system was improved and more capacity is provided for the Lot 1 of Harmony Technology Park Fourth Filing property north of the Brinkman Construction property. In the 100-year event, the orifice plate will restrict flows and allow 0.93 feet of ponding above the bioretention area and utilize the 8,5,32 cubic feet of volume provided in the proposed pond area up to an elevation of 4909.93 feet with top of pond elevation being 4910.45 feet. In the 100-year event, all stormwater will be conveyed through the outlet structure up to an elevation 4909.93 feet. Because of this, no formal emergency overflow/spillway has been designed. However, there is a small area in the southern berm of the pond that sits at an elevation of 4910.45 feet which is 0.52 feet below top of pond that will allow for water to spill south which will only be utilized during an emergency situation. This water will pond between the property line and northern edge of walk adjacent to Precision Drive before spilling over the walk and into Precision Drive to the east of the site. By reducing flows from the Precision Technology site with the outlet structure and orifice plate, this provides additional capacity in the storm sewer system downstream of the proposed site. This allows Lot 1 of Harmony Technology Park Fourth Filing to discharge approximately 15 cfs to the existing storm sewer stub located on the south side of that lot. F INAL D RAINAGE R EPORT P RECISION T ECHNOLOGY F ORT C OLLINS , CO 8 U20015_Drainage Report Drainage Summary A basin summary table is included below: Proposed Basins Basin Area %I C2 C100 Q2 Q100 (acre) (cfs) (cfs) A1 0.24 2% 0.25 0.31 0.16 0.71 A2 0.10 85%0.85 1.00 0.25 1.04 A3 0.16 86% 0.86 1.00 0.40 1.62 A4 0.10 90% 0.95 1.00 0.28 1.01 A5 0.08 2% 0.25 0.31 0.05 0.23 A6 0.52 83% 0.84 1.00 1.15 5.14 A1.1 0.10 90% 0.95 1.00 0.27 1.00 A1.2 0.06 90% 0.95 1.00 0.16 0.58 A1.3 0.47 90%0.95 1.00 1.26 4.63 A1.4 0.45 90%0.95 1.00 1.21 4.43 A1.5 0.46 90% 0.95 1.00 1.23 4.53 A1.6 0.50 90% 0.95 1.00 1.34 4.93 A Total 3.24 80% 0.85 1.00 5.16 21.10 B1 0.57 29% 0.46 0.58 0.52 2.37 B1.1 0.08 90% 0.95 1.00 0.21 0.78 B1.2 0.15 90% 0.95 1.00 0.40 1.47 B1.3 0.10 90%0.95 1.00 0.28 1.01 B1.4 0.06 90% 0.95 1.00 0.15 0.57 B1.5 0.06 90% 0.95 1.00 0.17 0.63 B Total 1.02 56% 0.68 0.84 1.74 6.82 C1 0.10 24% 0.42 0.53 0.12 0.53 D1 0.10 40% 0.55 0.69 0.16 0.71 E1 0.09 2% 0.25 0.31 0.06 0.28 E2 0.30 77% 0.78 0.98 0.66 2.88 E Total 0.39 59% 0.66 0.82 0.73 3.17 Proposed Total 4.85 71%0.78 0.98 7.90 32.32 In its improved condition, the total site imperviousness is approximately 71% and well below the assumed 80% in the HTP Site Master Plan Drainage Report; therefore, the site drainage is in compliance with the HTP Site Master Plan Drainage Report. Standard Operating Procedures (SOPs) In order for physical stormwater Best Management Practices (BMPs) to be effective, proper maintenance is essential. Maintenance includes both routinely scheduled activities, as well as non-routine repairs that may be required after large storms, or as a result of other unforeseen problems. Standard Operating Procedures should clearly identify BMP maintenance responsibility. BMP maintenance is typically the responsibility of the entity owning the BMP. Identifying who is responsible for maintenance of BMPs and ensuring that an adequate budget is allocated for maintenance is critical to the long-term success of BMPs. Maintenance responsibility may be assigned either publicly or privately. For this project, the privately owned BMPs including grass swales and the bioretention pond, are to be maintained by the property owner. Storm Sewers There are multiple storm sewer networks proposed with the site improvements. Related to conveyance of runoff to the bioretention pond, multiple roof drain systems are interconnected to storm sewer infrastructure which outfalls to the bioretention pond. Additional roof drains on the south side of the site are interconnected as well but outfall to existing storm F INAL D RAINAGE R EPORT P RECISION T ECHNOLOGY F ORT C OLLINS , CO 9 U20015_Drainage Report sewer within Precision Drive. All storm sewers will be private and are sized to accommodate the flows from the 100-year storm event. Hydraulic computations of these systems are provided in the appendix. Inlets There are multiple inlets proposed with the site improvements, including Nyloplast (or similar) drain inlets, a Type C Inlet used as the outlet structure and several combination inlets. The combination Inlets are designed in a sump condition to capture runoff produced in Basins A2, A3, and A6. Other on-site drain inlets are designed in a sump condition and are designed to convey runoff produced within smaller interior basins to the proposed storm sewer and bioretention ponds. The Type C inlet will be used as an outlet structure for the proposed bioretention pond and will convey 100-yr storm events from the pond to downstream storm sewer infrastructure. All inlets on the site are sized to provide adequate capacity and convey the 100-year storm event. Hydraulic computations of these systems will be provided with the initial final compliance submittal. V.EROSION CONTROL A separate Erosion Control Report / Storm Water Management Plan (SWMP) will be prepared for the site in accordance with the Stormwater Discharge Permit for Colorado Department of Public Health and Environment as the site will disturb an area greater than 1-acre. The Erosion Control Report will be completed during the Final Compliance phase of the project and will include more detailed information on the sediment and erosion control items for this project. It is intended that the proposed improvements will comply with Erosion Control Criteria per the FCSCM, and all Erosion Control Materials will be provided with the Final Drainage Report. At a minimum, the following temporary BMP’s will be installed and maintained to control on-site erosion and prevent sediment from traveling off-site during construction: Silt Fence – a woven synthetic fabric that filters runoff. The silt fence is a temporary barrier that is placed at the base of a disturbed area. Vehicle Tracking Control – a stabilized stone pad located at points of ingress and egress on a construction site. The stone pad is designed to reduce the amount of mud transported onto public roads by construction traffic. Riprap – Riprap will be used downstream of all storm sewer outfalls to control erosion of the receiving channels. Inlet Protection – acts as a sediment filter. It is a temporary BMP and requires proper installation and maintenance to ensure their performance. Straw Wattles – wattles act as a sediment filter in swales around inlets. They are a temporary BMP and require proper installation and maintenance to ensure their performance. The contractor shall store all construction materials and equipment and shall provide maintenance and fueling of equipment in confined areas on-site from which runoff will be contained and filtered. Temporary Best Management Practices (BMP’s) will be inspected by the contractor at a minimum of once every two weeks and after each significant storm event. VI.CONCLUSIONS A. COMPLIANCE WITH STANDARDS Storm drainage calculations have followed the guidelines provided by the Urban Storm Drainage Criteria Manuals Volumes 1, 2 and 3 and the City of Fort Collins Stormwater Criteria Manual. B. DRAINAGE CONCEPT The drainage system has been designed to convey the runoff to the designated design points and the existing public infrastructure and regional detention ponds in an effective, safe manner. No negative impacts are anticipated to the City of Fort Collins Master Drainage Plan, to the HTP Site Master Plan, or to downstream properties or infrastructure due to the proposed improvements. F INAL D RAINAGE R EPORT P RECISION T ECHNOLOGY F ORT C OLLINS , CO 10 U20015_Drainage Report C. STORMWATER QUALITY Multiple long-term stormwater quality measures have been selected for the site that will provide treatment of stormwater prior it to being discharged from the site. For this site this includes a bioretention pond and offsite regional detention ponds that include stormwater quality. F INAL D RAINAGE R EPORT P RECISION T ECHNOLOGY F ORT C OLLINS , CO 11 U20015_Drainage Report VII.REFERENCES 1. City of Fort Collins Stormwater Criteria Manual, City of Fort Collins, Colorado, November 2017. 2. Urban Storm Drainage Criteria Manual Volume 1 and 2, Urban Drainage and Flood Control District, Denver, Colorado, June 2001, Revised April 2008. 3. Final Drainage and Erosion Control Study for Harmony Technology Park Site Master Plan, Stantec, Fort Collins, Colorado, May 2008. 4. Final Drainage and Erosion Control Study for Harmony Technology Park Third Filing, Stantec, Fort Collins, Colorado, May 2008. 5. Final Drainage and Erosion Control Report for Harmony Technology Park Fourth Filing, Aspen Engineering, Fort Collins, Colorado, January 2014. 6. Natural Resources Conservation Service Web Soil Survey at: websoilsurvey.nrcs.usda.gov/app 7. Preliminary Flood Insurance Rate Map, FEMA, Panel 0994F, https://hazards.fema.gov/femaportal/ 8. Stormwater Discharges Associated with Construction Activity, Stormwater Management Plan Preparation Guides, State of Colorado, www.colorado.com A PPENDIX A H YDROLOGY C ALCULATIONS RU N O F F C O E F F I C I E N T S A N D % I M P E R V I O U S Pr e c i s i o n T e c h n o l o g y , F o r t C o l l i n s , C O Ba s i n De s i g n P t . Co m p o s i t e To t a l T o t a l Ro o f (1 ) As p h a l t Co n c r e t e (1 ) Gr a v e l (1 ) La w n s (3 ) Im p e r v i o u s n e s s C2 C10 0 %I = 9 0 % % I = 1 0 0 % %I = 9 0 % %I = 4 0 % % I = 2 % C= 0 . 9 5 C = 0 . 9 5 C = 0 . 9 5 C = 0 . 5 0 C = 0 . 2 5 (% I ) A1 A 1 0. 2 4 1 0 , 6 6 7 - - - - 1 0 , 6 6 7 2. 0 % 0 . 2 5 0 . 3 1 A2 A 2 0. 1 0 4 , 5 6 7 - 3 , 5 3 4 3 9 8 - 6 3 6 85 . 5 % 0 . 8 5 1 . 0 0 A3 A 3 0. 1 6 7 , 1 1 0 - 5 , 3 0 6 8 8 1 - 9 2 3 86 . 0 % 0 . 8 6 1 . 0 0 A4 A 4 0. 1 0 4 , 4 3 3 9 0 4 - 3 , 5 2 8 - - 90 . 0 % 0 . 9 5 1 . 0 0 A5 A 5 0. 0 8 3 , 6 7 4 - - - - 3 , 6 7 4 2. 0 % 0 . 2 5 0 . 3 1 A6 A 6 0. 5 2 2 2 , 4 8 2 - 1 5 , 7 3 9 3 , 0 7 1 - 3 , 6 7 2 82 . 6 % 0 . 8 4 1 . 0 0 A1 . 1 A 1 . 1 0. 1 0 4 , 3 9 0 4 , 3 9 0 - - - - 90 . 0 % 0 . 9 5 1 . 0 0 A1 . 2 A 1 . 2 0. 0 6 2 , 5 2 9 2 , 5 2 9 - - - - 90 . 0 % 0 . 9 5 1 . 0 0 A1 . 3 A 1 . 3 0. 4 7 2 0 , 2 6 0 2 0 , 2 6 0 - - - - 90 . 0 % 0 . 9 5 1 . 0 0 A1 . 4 A 1 . 4 0. 4 5 1 9 , 4 0 9 1 9 , 4 0 9 - - - - 90 . 0 % 0 . 9 5 1 . 0 0 A1 . 5 A 1 . 5 0. 4 6 1 9 , 8 5 3 1 9 , 8 5 3 - - - - 90 . 0 % 0 . 9 5 1 . 0 0 A1 . 6 A 1 . 6 0. 5 0 2 1 , 5 9 1 2 1 , 5 9 1 - - - - 90 . 0 % 0 . 9 5 1 . 0 0 A T o t a l A T o t a l 3. 2 4 1 4 0 , 9 6 6 8 8 , 9 3 7 2 4 , 5 7 8 7 , 8 7 8 - 1 9 , 5 7 2 79 . 5 % 0 . 8 5 1 . 0 0 B1 B 1 0. 5 7 2 4 , 9 6 6 - 1 , 8 3 7 5 , 7 0 9 - 1 7 , 4 2 0 29 . 3 % 0 . 4 6 0 . 5 8 B1 . 1 B 1 . 1 0. 0 8 3 , 3 9 9 3 , 3 9 9 - - - - 90 . 0 % 0 . 9 5 1 . 0 0 B1 . 2 B 1 . 2 0. 1 5 6 , 4 2 0 6 , 4 2 0 - - - - 90 . 0 % 0 . 9 5 1 . 0 0 B1 . 3 B 1 . 3 0. 1 0 4 , 4 2 9 4 , 4 2 9 - - - - 90 . 0 % 0 . 9 5 1 . 0 0 B1 . 4 B 1 . 4 0. 0 6 2 , 4 8 4 2 , 4 8 4 - - - - 90 . 0 % 0 . 9 5 1 . 0 0 B1 . 5 B 1 . 5 0. 0 6 2 , 7 5 5 2 , 7 5 5 - - - - 90 . 0 % 0 . 9 5 1 . 0 0 B T o t a l B T o t a l 1. 0 2 4 4 , 4 5 3 1 9 , 4 8 7 1 , 8 3 7 5 , 7 0 9 - 1 7 , 4 2 0 55 . 9 % 0 . 6 8 0 . 8 4 C1 C 1 0. 1 0 4 , 3 7 7 - - 1 , 0 7 9 - 3 , 2 9 8 23 . 7 % 0 . 4 2 0 . 5 3 D1 D 1 0. 1 0 4 , 4 8 6 - - 1 , 9 4 3 - 2 , 5 4 3 40 . 1 % 0 . 5 5 0 . 6 9 E1 E 1 0. 0 9 3 , 9 6 2 - - - - 3 , 9 6 2 2. 0 % 0 . 2 5 0 . 3 1 E2 E 2 0. 3 0 1 2 , 9 1 0 - 9 , 8 1 8 - - 3 , 0 9 2 76 . 5 % 0 . 7 8 0 . 9 8 E T o t a l E T o t a l 0. 3 9 1 6 , 8 7 2 - 9 , 8 1 8 - - 7 , 0 5 4 59 . 0 % 0 . 6 6 0 . 8 2 4. 8 5 2 1 1 , 1 5 3 1 0 8 , 4 2 4 3 6 , 2 3 3 1 6 , 6 1 0 - 4 9 , 8 8 7 7 0 . 9 % 0 . 7 8 0 . 9 8 No t e s : (1 ) R e c o m m e n d e d % I m p e r v i o u s n e s s V a l u e s p e r T a b l e 4 . 1 - 3 S u r f a c e T y p e - P e r c e n t I m p e r v i o u s i n F o r t C o l l i n s S t o r m w a t e r C r i t e r i a M a n u a l (2 ) R u n o f f C i s b a s e d T a b l e 3 . 2 - 2 . S u r f a c e T y p e - R u n o f f C o e f f i c i e n t s a n d T a b l e 3 . 2 - 3 . F r e q u e n c y A d j u s t m e n t F a c t o r s i n F o r t C o l l i n s S t o r m w a t e r M a n u a l (3 ) R u n o f f C f o r L a w n s b a s e d o f f o f L a w n s , C l a y e y S o i l , A v g S l o p e 2 - 7 % Pr o p o s e d T o t a l Pr o p o s e d B a s i n s Ar e a s Co m p o s i t e R u n o f f C o e f f i c i e n t s (2 ) Da t e : 1 2 / 8 / 2 0 2 0 C: \ U n i t e d C i v i l D r o p b o x \ P r o j e c t s \ U 2 0 0 1 5 - P R C S P r e c i s i o n T e c h I I \ R e p o r t s \ D r a i n a g e \ C a l c u l a t i o n s \ U 2 0 0 1 5 - D r a i n C a l c s 2 - Y E A R T I M E O F C O N C E N T R A T I O N Pr e c i s i o n T e c h n o l o g y , F o r t C o l l i n s , C O Ba s i n De s i g n P t . Ar e a C(1 ) Le n g t h S l o p e ti(2 ) Le n g t h S l o p e Cv Ve l o c i t y (3 ) tt(4 ) Ch e c k t c? To t a l L e n g t h tc(5 ) A1 A 1 0 . 2 4 0. 2 5 22 5. 0 % 4. 2 14 9 0. 5 % 20 1. 4 1 . 8 6 . 0 Y e s 1 7 1 1 1 6. 0 A2 A 2 0 . 1 0 0 . 8 5 4 1 2 . 0 % 2. 3 11 8 3. 0 % 20 3. 5 0 . 6 2 . 8 Y e s 1 5 9 1 1 5. 0 A3 A 3 0 . 1 6 0 . 8 6 2 4 2 . 0 % 1. 7 14 7 2. 0 % 20 2. 8 0 . 9 2 . 6 Y e s 1 7 1 1 1 5. 0 A4 A 4 0 . 1 0 0 . 9 5 3 7 5 . 0 % 1. 0 50 0. 5 % 20 1. 4 0 . 6 1 . 6 Y e s 8 7 1 0 5. 0 A5 A 5 0 . 0 8 0 . 2 5 2 5 2 . 0 % 6. 1 15 0 2. 0 % 15 2. 1 1 . 2 7 . 3 Y e s 1 7 5 1 1 7. 3 A6 A 6 0 . 5 2 0 . 8 4 6 0 2 . 0 % 2. 9 29 7 0. 5 % 20 1. 4 3 . 5 6 . 4 Y e s 3 5 7 1 2 6. 4 A1 . 1 A 1 . 1 0 . 1 0 0 . 9 5 6 8 2 . 1 % 1. 7 1 33 . 0 % 20 11 . 5 0 . 0 1 . 7 Y e s 6 9 1 0 5. 0 A1 . 2 A 1 . 2 0 . 0 6 0 . 9 5 6 6 2 . 1 % 1. 7 1 33 . 0 % 20 11 . 5 0 . 0 1 . 7 Y e s 6 7 1 0 5. 0 A1 . 3 A 1 . 3 0 . 4 7 0 . 9 5 1 5 6 2 . 1 % 2. 6 1 33 . 0 % 20 11 . 5 0 . 0 2 . 6 Y e s 1 5 7 1 1 5. 0 A1 . 4 A 1 . 4 0 . 4 5 0 . 9 5 1 4 6 2 . 1 % 2. 6 1 33 . 0 % 20 11 . 5 0 . 0 2 . 6 Y e s 1 4 7 1 1 5. 0 A1 . 5 A 1 . 5 0 . 4 6 0 . 9 5 1 3 8 2 . 1 % 2. 5 1 33 . 0 % 20 11 . 5 0 . 0 2 . 5 Y e s 1 3 9 1 1 5. 0 A1 . 6 A 1 . 6 0 . 5 0 0 . 9 5 1 2 8 2 . 1 % 2. 4 1 33 . 0 % 20 11 . 5 0 . 0 2 . 4 Y e s 1 2 9 1 1 5. 0 A R o u t e d A R o u t e d 3 . 2 4 0 . 8 5 1 2 8 2 . 1 % 4. 0 83 2 0. 5 % 15 1. 1 1 3 . 1 1 7 . 0 Y e s 9 6 0 1 5 15 . 3 B1 B 1 0 . 5 7 0 . 4 6 6 8 2 . 0 % 7. 6 55 7 0. 7 % 20 1. 7 5 . 5 1 3 . 1 Y e s 6 2 5 1 3 13 . 1 B1 . 1 B 1 . 1 0 . 0 8 0 . 9 5 7 5 2 . 1 % 1. 8 1 33 . 0 % 20 11 . 5 0 . 0 1 . 8 Y e s 7 6 1 0 5. 0 B1 . 2 B 1 . 2 0 . 1 5 0 . 9 5 1 0 0 2 . 1 % 2. 1 1 33 . 0 % 20 11 . 5 0 . 0 2 . 1 Y e s 1 0 1 1 1 5. 0 B1 . 3 B 1 . 3 0 . 1 0 0 . 9 5 1 0 6 2 . 1 % 2. 2 1 33 . 0 % 20 11 . 5 0 . 0 2 . 2 Y e s 1 0 7 1 1 5. 0 B1 . 4 B 1 . 4 0 . 0 6 0 . 9 5 6 1 2 . 1 % 1. 7 1 33 . 0 % 20 11 . 5 0 . 0 1 . 7 Y e s 6 2 1 0 5. 0 B1 . 5 B 1 . 5 0 . 0 6 0 . 9 5 4 6 2 . 1 % 1. 4 1 33 . 0 % 20 11 . 5 0 . 0 1 . 4 Y e s 4 7 1 0 5. 0 B T o t a l B T o t a l 1 . 0 2 0 . 6 8 - - - - - - - C1 C 1 0 . 1 0 0 . 4 2 7 5 . 0 % 1. 9 10 0 0. 5 % 20 1. 4 1 . 2 3 . 1 Y e s 1 0 7 1 1 5. 0 D1 D 1 0 . 1 0 0 . 5 5 7 5 . 0 % 1. 5 15 0 1. 0 % 20 2. 0 1 . 3 2 . 8 Y e s 1 5 7 1 1 5. 0 E1 E 1 0 . 0 9 0 . 2 5 8 2 5 . 0 % 1. 5 1 2. 0 % 15 2. 1 0 . 0 1 . 5 Y e s 9 1 0 5. 0 E2 E 2 0 . 3 0 0 . 7 8 6 5 . 0 % 0. 8 18 8 0. 5 % 20 1. 4 2 . 2 3 . 0 Y e s 1 9 4 1 1 5. 0 E T o t a l E T o t a l 0 . 3 9 0 . 6 6 - - - - - - - No t e s : (1 ) C = C x*C f (2 ) ti = [ 1 . 8 7 ( 1 . 1 - C xCf)L 1/ 2 ]/ S 1/ 3 , S = s l o p e i n % , L = l e n g t h o f o v e r l a n d f l o w ( 3 0 0 ' m a x ) (3 ) V= C vS0. 5 , S = w a t e r c o u r s e s l o p e i n f t / f t , U D F C D E q u a t i o n R O - 4 (4 ) tt=L / ( V * 6 0 s e c / m i n ) (5 ) tc c h e c k ( f o r u r b a n o r d e v e l o p e d a r e a s o n l y ) = t o t a l l e n g t h / 1 8 0 + 1 0 (6 ) mi n t c = 5 m i n P r o p o s e d B a s i n s Tr a v e l / C h a n n e l i z e d T i m e o f F l o w ( t t) ti+t t tc C h e c k f o r U r b a n i z e d B a s i n s Fi n a l t c(6 ) Da t e : 1 2 / 8 / 2 0 2 0 C: \ U n i t e d C i v i l D r o p b o x \ P r o j e c t s \ U 2 0 0 1 5 - P R C S P r e c i s i o n T e c h I I \ R e p o r t s \ D r a i n a g e \ C a l c u l a t i o n s \ U 2 0 0 1 5 - D r a i n C a l c s 10 0 - Y E A R T I M E O F C O N C E N T R A T I O N Pr e c i s i o n T e c h n o l o g y , F o r t C o l l i n s , C O Ba s i n De s i g n P t . Ar e a C(1 ) Le n g t h S l o p e ti(2 ) Le n g t h S l o p e Cv Ve l o c i t y (3 ) tt(4 ) Ch e c k t c? To t a l L e n g t h tc(5 ) A1 A 1 0 . 2 4 0. 3 1 22 5. 0 % 3. 9 14 9 0. 5 % 20 1. 4 1 . 8 5 . 7 Y e s 1 7 1 1 1 5. 7 A2 A 2 0 . 1 0 1 . 0 0 4 1 2 . 0 % 0. 9 11 8 3. 0 % 20 3. 5 0 . 6 1 . 5 Y e s 1 5 9 1 1 5. 0 A3 A 3 0 . 1 6 1 . 0 0 2 4 2 . 0 % 0. 7 14 7 2. 0 % 20 2. 8 0 . 9 1 . 6 Y e s 1 7 1 1 1 5. 0 A4 A 4 0 . 1 0 1 . 0 0 3 7 5 . 0 % 0. 6 50 0. 5 % 20 1. 4 0 . 6 1 . 2 Y e s 8 7 1 0 5. 0 A5 A 5 0 . 0 8 0 . 3 1 2 5 2 . 0 % 5. 7 15 0 2. 0 % 15 2. 1 1 . 2 6 . 8 Y e s 1 7 5 1 1 6. 8 A6 A 6 0 . 5 2 1 . 0 0 6 0 2 . 0 % 1. 1 29 7 0. 5 % 20 1. 4 3 . 5 4 . 6 Y e s 3 5 7 1 2 5. 0 A1 . 1 A 1 . 1 0 . 1 0 1 . 0 0 6 8 2 . 1 % 1. 2 1 33 . 0 % 20 11 . 5 0 . 0 1 . 2 Y e s 6 9 1 0 5. 0 A1 . 2 A 1 . 2 0 . 0 6 1 . 0 0 6 6 2 . 1 % 1. 1 1 33 . 0 % 20 11 . 5 0 . 0 1 . 1 Y e s 6 7 1 0 5. 0 A1 . 3 A 1 . 3 0 . 4 7 1 . 0 0 1 5 6 2 . 1 % 1. 8 1 33 . 0 % 20 11 . 5 0 . 0 1 . 8 Y e s 1 5 7 1 1 5. 0 A1 . 4 A 1 . 4 0 . 4 5 1 . 0 0 1 4 6 2 . 1 % 1. 7 1 33 . 0 % 20 11 . 5 0 . 0 1 . 7 Y e s 1 4 7 1 1 5. 0 A1 . 5 A 1 . 5 0 . 4 6 1 . 0 0 1 3 8 2 . 1 % 1. 7 1 33 . 0 % 20 11 . 5 0 . 0 1 . 7 Y e s 1 3 9 1 1 5. 0 A1 . 6 A 1 . 6 0 . 5 0 1 . 0 0 1 2 8 2 . 1 % 1. 6 1 33 . 0 % 20 11 . 5 0 . 0 1 . 6 Y e s 1 2 9 1 1 5. 0 A R o u t e d A R o u t e d 3 . 2 4 1 . 0 0 1 2 8 2 . 1 % 1. 6 83 2 0. 5 % 15 1. 1 1 3 . 1 1 4 . 7 Y e s 9 6 0 1 5 14 . 7 B1 B 1 0 . 5 7 0 . 5 8 6 8 2 . 0 % 6. 2 55 7 0. 7 % 20 1. 7 5 . 5 1 1 . 7 Y e s 6 2 5 1 3 11 . 7 B1 . 1 B 1 . 1 0 . 0 8 1 . 0 0 7 5 2 . 1 % 1. 2 1 33 . 0 % 20 11 . 5 0 . 0 1 . 2 Y e s 7 6 1 0 5. 0 B1 . 2 B 1 . 2 0 . 1 5 1 . 0 0 1 0 0 2 . 1 % 1. 4 1 33 . 0 % 20 11 . 5 0 . 0 1 . 4 Y e s 1 0 1 1 1 5. 0 B1 . 3 B 1 . 3 0 . 1 0 1 . 0 0 1 0 6 2 . 1 % 1. 5 1 33 . 0 % 20 11 . 5 0 . 0 1 . 5 Y e s 1 0 7 1 1 5. 0 B1 . 4 B 1 . 4 0 . 0 6 1 . 0 0 6 1 2 . 1 % 1. 1 1 33 . 0 % 20 11 . 5 0 . 0 1 . 1 Y e s 6 2 1 0 5. 0 B1 . 5 B 1 . 5 0 . 0 6 1 . 0 0 4 6 2 . 1 % 1. 0 1 33 . 0 % 20 11 . 5 0 . 0 1 . 0 Y e s 4 7 1 0 5. 0 B T o t a l B T o t a l 1 . 0 2 0 . 8 4 0 0 . 0 % - 0 0. 0 % 0 - - - - - - C1 C 1 0 . 1 0 0 . 5 3 7 5 . 0 % 1. 6 10 0 0. 5 % 20 1. 4 1 . 2 2 . 8 Y e s 1 0 7 1 1 5. 0 D1 D 1 0 . 1 0 0 . 6 9 7 5 . 0 % 1. 1 15 0 1. 0 % 20 2. 0 1 . 3 2 . 4 Y e s 1 5 7 1 1 5. 0 E1 E 1 0 . 0 9 0 . 3 1 8 2 5 . 0 % 1. 4 1 2. 0 % 15 2. 1 0 . 0 1 . 4 Y e s 9 1 0 5. 0 E2 E 2 0 . 3 0 0 . 9 8 6 5 . 0 % 0. 3 18 8 0. 5 % 20 1. 4 2 . 2 2 . 5 Y e s 1 9 4 1 1 5. 0 E T o t a l E T o t a l 0 . 3 9 0 . 8 2 - - - - - - - No t e s : (1 ) C = C x*C f (2 ) ti = [ 1 . 8 7 ( 1 . 1 - C xCf)L 1/ 2 ]/ S 1/ 3 , S = s l o p e i n % , L = l e n g t h o f o v e r l a n d f l o w ( 3 0 0 ' m a x ) (3 ) V= C vS0. 5 , S = w a t e r c o u r s e s l o p e i n f t / f t , U D F C D E q u a t i o n R O - 4 (4 ) tt=L / ( V * 6 0 s e c / m i n ) (5 ) tc c h e c k ( f o r u r b a n o r d e v e l o p e d a r e a s o n l y ) = t o t a l l e n g t h / 1 8 0 + 1 0 (6 ) mi n t c = 5 m i n P r o p o s e d B a s i n s Tr a v e l / C h a n n e l i z e d T i m e o f F l o w ( t t) ti+t t tc C h e c k f o r U r b a n i z e d B a s i n s Fi n a l t c(6 ) Da t e : 1 2 / 8 / 2 0 2 0 C: \ U n i t e d C i v i l D r o p b o x \ P r o j e c t s \ U 2 0 0 1 5 - P R C S P r e c i s i o n T e c h I I \ R e p o r t s \ D r a i n a g e \ C a l c u l a t i o n s \ U 2 0 0 1 5 - D r a i n C a l c s RA T I O N A L M E T H O D P E A K R U N O F F Pr e c i s i o n T e c h n o l o g y , F o r t C o l l i n s , C O Ba s i n D e s i g n P t . A r e a 2 - Y e a r 1 0 0 - Y e a r tc tc C2 C10 0 I2 I10 0 Q2 Q10 0 A1 A 1 0 . 2 4 6 6 0 . 2 5 0 . 3 1 2 . 6 7 9 . 3 1 0 . 1 6 0 . 7 1 A2 A 2 0 . 1 0 5 5 0 . 8 5 1 . 0 0 2 . 8 5 9 . 9 5 0 . 2 5 1 . 0 4 A3 A 3 0 . 1 6 5 5 0 . 8 6 1 . 0 0 2 . 8 5 9 . 9 5 0 . 4 0 1 . 6 2 A4 A 4 0 . 1 0 5 5 0 . 9 5 1 . 0 0 2 . 8 5 9 . 9 5 0 . 2 8 1 . 0 1 A5 A 5 0 . 0 8 7 7 0 . 2 5 0 . 3 1 2 . 5 2 8 . 8 0 0 . 0 5 0 . 2 3 A6 A 6 0 . 5 2 6 5 0 . 8 4 1 . 0 0 2 . 6 7 9 . 9 5 1 . 1 5 5 . 1 4 A1 . 1 A 1 . 1 0 . 1 0 5 5 0 . 9 5 1 . 0 0 2 . 8 5 9 . 9 5 0 . 2 7 1 . 0 0 A1 . 2 A 1 . 2 0 . 0 6 5 5 0 . 9 5 1 . 0 0 2 . 8 5 9 . 9 5 0 . 1 6 0 . 5 8 A1 . 3 A 1 . 3 0 . 4 7 5 5 0 . 9 5 1 . 0 0 2 . 8 5 9 . 9 5 1 . 2 6 4 . 6 3 A1 . 4 A 1 . 4 0 . 4 5 5 5 0 . 9 5 1 . 0 0 2 . 8 5 9 . 9 5 1 . 2 1 4 . 4 3 A1 . 5 A 1 . 5 0 . 4 6 5 5 0 . 9 5 1 . 0 0 2 . 8 5 9 . 9 5 1 . 2 3 4 . 5 3 A1 . 6 A 1 . 6 0 . 5 0 5 5 0 . 9 5 1 . 0 0 2 . 8 5 9 . 9 5 1 . 3 4 4 . 9 3 A R o u t e d A R o u t e d 3 . 2 4 1 5 1 5 0 . 8 5 1 . 0 0 1 . 8 7 6 . 5 2 5 . 1 6 2 1 . 1 0 B1 B 1 0 . 5 7 1 3 1 2 0 . 4 6 0 . 5 8 1 . 9 8 7 . 1 6 0 . 5 2 2 . 3 7 B1 . 1 B 1 . 1 0 . 0 8 5 5 0 . 9 5 1 . 0 0 2 . 8 5 9 . 9 5 0 . 2 1 0 . 7 8 B1 . 2 B 1 . 2 0 . 1 5 5 5 0 . 9 5 1 . 0 0 2 . 8 5 9 . 9 5 0 . 4 0 1 . 4 7 B1 . 3 B 1 . 3 0 . 1 0 5 5 0 . 9 5 1 . 0 0 2 . 8 5 9 . 9 5 0 . 2 8 1 . 0 1 B1 . 4 B 1 . 4 0 . 0 6 5 5 0 . 9 5 1 . 0 0 2 . 8 5 9 . 9 5 0 . 1 5 0 . 5 7 B1 . 5 B 1 . 5 0 . 0 6 5 5 0 . 9 5 1 . 0 0 2 . 8 5 9 . 9 5 0 . 1 7 0 . 6 3 B T o t a l B T o t a l 1 . 0 2 - - 0 . 6 8 0 . 8 4 - - 1 . 7 4 6 . 8 2 C1 C 1 0 . 1 0 5 5 0 . 4 2 0 . 5 3 2 . 8 5 9 . 9 5 0 . 1 2 0 . 5 3 D1 D 1 0 . 1 0 5 5 0 . 5 5 0 . 6 9 2 . 8 5 9 . 9 5 0 . 1 6 0 . 7 1 E1 E 1 0 . 0 9 5 5 0 . 2 5 0 . 3 1 2 . 8 5 9 . 9 5 0 . 0 6 0 . 2 8 E2 E 2 0 . 3 0 5 5 0 . 7 8 0 . 9 8 2 . 8 5 9 . 9 5 0 . 6 6 2 . 8 8 E T o t a l E T o t a l 0 . 3 9 - - 0 . 6 6 0 . 8 2 - - 0 . 7 3 3 . 1 7 7. 9 0 3 2 . 3 2 To t a l s P r o p o s e d B a s i n s Ru n o f f C o e f f i c i e n t s R a i n f a l l I n t e n s i t y P e a k D i s c h a r g e Da t e : 1 2 / 8 / 2 0 2 0 C: \ U n i t e d C i v i l D r o p b o x \ P r o j e c t s \ U 2 0 0 1 5 - P R C S P r e c i s i o n T e c h I I \ R e p o r t s \ D r a i n a g e \ C a l c u l a t i o n s \ U 2 0 0 1 5 - D r a i n C a l c s A PPENDIX B H YDRAULIC C ALCULATIONS LOW IMPACT DEVELOPMENT SUMMARY Precision Technology, Fort Collins, CO Basin Proposed Impervious Area LID Treatment Area Treated % of Site Treated (sf) (sf) (%) A1 213 Bioretention Pond A 213 0% A2 3,904 Bioretention Pond A 3,904 3% A3 6,117 Bioretention Pond A 6,117 4% A4 3,990 Bioretention Pond A 3,990 3% A5 73 Bioretention Pond A 73 0% A6 18,576 Bioretention Pond A 18,576 12% A1.1 3,951 Bioretention Pond A 3,951 3% A1.2 2,276 Bioretention Pond A 2,276 2% A1.3 18,234 Bioretention Pond A 18,234 12% A1.4 17,468 Bioretention Pond A 17,468 12% A1.5 17,868 Bioretention Pond A 17,868 12% A1.6 19,432 Bioretention Pond A 19,432 13% A Total 112,103 Bioretention Pond A 112,103 75% B1 7,323 None -0% B1.1 3,059 None -0% B1.2 5,778 None -0% B1.3 3,986 None -0% B1.4 2,236 None -0% B1.5 2,480 None -0% B Total 24,862 None -0% C1 1,037 None -0% D1 1,800 None -0% E1 79 None -0% E2 9,880 None -0% E Total 9,959 None -0% Total Site 149,761 112,103 75% Low Impact Development (LID) Treated Areas Date: 12/8/2020 C:\United Civil Dropbox\Projects\U20015 - PRCS Precision Tech II\Reports\Drainage\Calculations\U20015-Drain Calcs WA T E R Q U A L I T Y - L O W I M P A C T D E V E L O P M E N T Pr e c i s i o n T e c h n o l o g y , F o r t C o l l i n s , C O Re q u i r e d O n s i t e W a t e r Q u a l i t y C a p t u r e V o l u m e f o r L I D Ba s i n A r e a A r e a I m p e r v i o u s n e s s W a t e r s h e d W Q C V * (E x t e n d e d D e t e n t i o n ) (s f ) ( a c r e s ) ( % ) ( i n c h e s ) ( c f ) Ba s i n A - B i o r e t e n t i o n P o n d A1 1 0 , 6 6 7 0 . 2 4 5 2% 0. 0 1 1 1 A2 4 , 5 6 7 0 . 1 0 5 85 % 0. 2 9 1 1 1 A3 7 , 1 1 0 0 . 1 6 3 86 % 0. 3 0 1 7 5 A4 4 , 4 3 3 0 . 1 0 2 90 % 0. 3 2 1 1 9 E2 1 2 , 9 1 0 0 . 2 9 6 77 % 0. 2 5 2 6 5 A1 . 1 4 , 3 9 0 0 . 1 0 1 90 % 0. 3 2 1 1 8 A1 . 2 2 , 5 2 9 0 . 0 5 8 90 % 0. 3 2 6 8 A1 . 3 2 0 , 2 6 0 0 . 4 6 5 90 % 0. 3 2 5 4 2 A1 . 4 1 9 , 4 0 9 0 . 4 4 6 90 % 0. 3 2 5 1 9 A1 . 5 1 9 , 8 5 3 0 . 4 5 6 90 % 0. 3 2 5 3 1 A1 . 6 2 1 , 5 9 1 0 . 4 9 6 90 % 0. 3 2 5 7 8 A T o t a l 14 0 , 9 6 6 3 . 2 3 6 80 % 0. 2 6 3, 0 5 8 To t a l W Q P r o v i d e d o n s i t e i n B i o r e t e n t i o n P o n d 3 , 0 5 8 * B a s e d o n 1 2 h r s t o r a g e f o r u n d e r g r o u n d d e t e n t i o n Da t e : 1 2 / 8 / 2 0 2 0 C: \ U n i t e d C i v i l D r o p b o x \ P r o j e c t s \ U 2 0 0 1 5 - P R C S P r e c i s i o n T e c h I I \ R e p o r t s \ D r a i n a g e \ C a l c u l a t i o n s \ U 2 0 0 1 5 - D r a i n C a l c s DETENTION POND VOLUME (FAA Method) Precision Technology, Fort Collins, CO POND ID: Bioretention Pond 100 Year Storm Into Detention Facility Area =140,966 square feet Area =3.24 acres C 100 = 1.00 Release Rate Out of Pond Q OUT = 12.00 cfs Unit Flow =3.71 cfs/acre Notes: 1. Release Rate controlled by orifice plate in outlet structure. 2. Flowrate out of bioretention pond determined from allowable ponding volume in bioretention pond. 3. Pond is designed to provide WQ for all "A" Basins. Detention Volume Calculations Rainfall Rainfall Inflow Rate Inflow Volume Adjustment Average Outflow Volume Required Duration (T) Intensity (I) Qin 100*Area*I Vi=(Qin*T*60) Factor Outflow Rate Vo=Qav*T *60 Storage Volume m= 0.5(1 + Tc/T) Qav = m*Qout Vs=Vi-Vo min in/hr cfs ft 3 cfs ft 3 ft 3 5 9.95 32.2 9,660 1.00 12.00 3,600 6,060 10 7.72 25.0 14,990 1.00 12.00 7,200 7,790 15 6.52 21.1 18,990 1.00 12.00 10,800 8,190 20 5.60 18.1 21,747 1.00 12.00 14,400 7,347 25 4.98 16.1 24,174 1.00 12.00 18,000 6,174 30 4.52 14.6 26,329 1.00 12.00 21,600 4,729 35 4.08 13.2 27,727 1.00 12.00 25,200 2,527 40 3.74 12.1 29,047 1.00 12.00 28,800 247 45 3.46 11.2 30,232 1.00 12.00 32,400 -2,168 50 3.23 10.5 31,358 1.00 12.00 36,000 -4,642 55 3.03 9.8 32,358 1.00 12.00 39,600 -7,242 60 2.86 9.3 33,319 1.00 12.00 43,200 -9,881 70 2.59 8.4 35,203 1.00 12.00 50,400 -15,197 80 2.38 7.7 36,969 1.00 12.00 57,600 -20,631 90 2.21 7.2 38,620 1.00 12.00 64,800 -26,180 100 2.06 6.7 39,998 1.00 12.00 72,000 -32,002 110 1.94 6.3 41,435 1.00 12.00 79,200 -37,765 120 1.84 6.0 42,872 1.00 12.00 86,400 -43,528 Required Detention Volume V 100 = 8,190 cubic feet V 100 = 0.19 acre-ft Date: 12/8/2020 C:\United Civil Dropbox\Projects\U20015 - PRCS Precision Tech II\Reports\Drainage\Calculations\U20015-Drain Calcs DETENTION POND STORAGE AND ORIFICE CALCULATIONS Precision Technology, Fort Collins, CO POND ID: Bioretention Pond Stage Storage Calculations Elevation Area (sf) Depth (ft) Incremental Volume (cf) Volume total (cf) Volume total (ac- ft) 4,908.00 2,453.94 0.00 0 0 0.00 4,908.25 2,956.67 0.25 675 675 0.02 4,908.50 3,459.45 0.25 801 1,477 0.03 4,908.75 3,964.54 0.25 927 2,404 0.06 4,909.00 4,473.81 0.25 1,054 3,458 0.08 4,909.25 4,989.18 0.25 1,182 4,640 0.11 4,909.50 5,511.70 0.25 1,312 5,952 0.14 4,909.75 6,041.86 0.25 1,444 7,396 0.17 4,910.00 6,579.95 0.25 1,577 8,973 0.21 4,910.25 7,090.41 0.25 1,708 10,682 0.25 4,910.50 7,599.63 0.25 1,836 12,518 0.29 Detention Pond Storage & Water Quality Detention Volume Required =8,190 ft3 0.19 ac-ft Elev81 - Elev80 (VolRequired-Vol80)+Elev80 Vol81 - Vo80 Required W.S. Elevation = 4909.88 ft Provided W.S. Elevation = 4909.93 ft Detention Volume Provided = 8,532 ft3 0.20 ac-ft 100-year Depth D = 6.09 ft Top-of-Berm = 4910.45 ft Freeboard = 0.52 ft Orifice Opening and Water Quality Plate Orifice Flow Rate, Q = CoAo(2gHo)0.5 cfs Area of orifice Ao, ft2 = Q Co(2gHo)0.5 C o = 0.65 Q = Q out of pond = 12.00 cfs gravitational acceleration g = 32.2 ft/sec2 diam = 1.116 ft Effective head on orifice H o = D-1/2diam =5.53 ft Area of orifice A o = 0.98 ft2 Area of orifice A o = 140.85 in2 100-Year Orifice Diameter = 13.39 13 3/8 inches 100-Year Detention Volume and Elevations W.S. Elevation, ft = 100-Year Orifice Calculation Date: 12/8/2020 C:\United Civil Dropbox\Projects\U20015 - PRCS Precision Tech II\Reports\Drainage\Calculations\U20015-Drain Calcs IINLET CAPACITY Precision Technology, Fort Collins, CO INLET ID:Pond Outlet Structure Governing Equations: Inlet capacity equation at low flows (weir calculation): Where: P = 2(L + W) H = depth of water above the flowline Inlet capacity equation at higher flows (orifice calculation): Where: A = open area of the inlet grate H = depth of water above the centroid of the cross-sectional area (A) Input Parameters: Grate: Type C Wier Perimeter: 8.9 Open Area of Grate (ft2):9.4 Q100 = 12.00 cfs Grate Centroid Elevation (ft): 4909.00 Allowable Capacity: 50% Depth vs. Flow: Depth Elevation Shallow Orifice Actual Above Inlet Weir Flow Flow Flow (ft)(ft)(cfs)(cfs)(cfs) 0.00 4909.00 0.00 0.00 0.00 <---- 10-Year Flow 0.05 4909.05 0.15 5.62 0.15 0.10 4909.10 0.42 7.95 0.42 0.15 4909.15 0.78 9.74 0.78 0.20 4909.20 1.20 11.25 1.20 0.25 4909.25 1.68 12.58 1.68 0.30 4909.30 2.20 13.78 2.20 0.35 4909.35 2.78 14.88 2.78 0.40 4909.40 3.39 15.91 3.39 0.45 4909.45 4.05 16.87 4.05 0.50 4909.50 4.74 17.78 4.74 0.55 4909.55 5.47 18.65 5.47 0.60 4909.60 6.23 19.48 6.23 0.65 4909.65 7.03 20.28 7.03 0.70 4909.70 7.85 21.04 7.85 0.75 4909.75 8.71 21.78 8.71 0.80 4909.80 9.60 22.50 9.60 0.85 4909.85 10.51 23.19 10.51 0.93 4909.93 12.00 24.24 12.00 <----100-Year Flow 0.95 4909.95 12.42 24.51 12.42 1.00 4910.00 13.41 25.15 13.41 5.10.3 HPQ 5.0)2(67.0 gHAQ Calculations by: NKS Date: 12/8/2020 C:\United Civil Dropbox\Projects\U20015 - PRCS Precision Tech II\Reports\Drainage\Calculations\U20015-Drain Calcs Design Information (Input)MINOR MAJOR Type of Inlet Type = Local Depression (additional to continuous gutter depression 'a' from above)alocal =2.00 2.00 inches Number of Unit Inlets (Grate or Curb Opening) No = 1 1 Water Depth at Flowline (outside of local depression) Ponding Depth = 5.7 5.7 inches Grate Information MINOR MAJOR Length of a Unit Grate Lo (G) =3.00 3.00 feet Warning 5 Width of a Unit Grate Wo =1.73 1.73 feet Area Opening Ratio for a Grate (typical values 0.15-0.90)Aratio =0.43 0.43 Clogging Factor for a Single Grate (typical value 0.50 - 0.70)Cf (G) =0.50 0.50 Grate Weir Coefficient (typical value 2.15 - 3.60)Cw (G) =3.30 3.30 Grate Orifice Coefficient (typical value 0.60 - 0.80)Co (G) =0.60 0.60 Curb Opening Information MINOR MAJOR Length of a Unit Curb Opening Lo (C) =3.00 3.00 feet Height of Vertical Curb Opening in Inches Hvert =6.50 6.50 inches Height of Curb Orifice Throat in Inches Hthroat =5.25 5.25 inches Angle of Throat (see USDCM Figure ST-5) Theta = 0.00 0.00 degrees Side Width for Depression Pan (typically the gutter width of 2 feet)Wp =1.00 1.00 feet Clogging Factor for a Single Curb Opening (typical value 0.10)Cf (C) =0.10 0.10 Curb Opening Weir Coefficient (typical value 2.3-3.7)Cw (C) =3.70 3.70 Curb Opening Orifice Coefficient (typical value 0.60 - 0.70)Co (C) =0.66 0.66 Low Head Performance Reduction (Calculated)MINOR MAJOR Depth for Grate Midwidth dGrate =0.430 0.430 ft Depth for Curb Opening Weir Equation dCurb =0.40 0.40 ft Combination Inlet Performance Reduction Factor for Long Inlets RFCombination =0.90 0.90 Curb Opening Performance Reduction Factor for Long Inlets RFCurb =1.00 1.00 Grated Inlet Performance Reduction Factor for Long Inlets RFGrate =0.90 0.90 MINOR MAJOR Total Inlet Interception Capacity (assumes clogged condition)Qa =3.3 3.3 cfs Inlet Capacity IS GOOD for Minor and Major Storms(>Q PEAK)Q PEAK REQUIRED =0.3 1.0 cfs Warning 5: The width of unit is greater than the gutter width. CDOT/Denver 13 Combination INLET IN A SUMP OR SAG LOCATION Version 4.06 Released August 2018 H-VertH-Curb W Lo (C) Lo (G) Wo WP CDOT/Denver 13 Combination Override Depths UD-Inlet_v4.06, Inlet A1 (Basin A2) 12/8/2020, 6:19 PM Design Information (Input)MINOR MAJOR Type of Inlet Type = Local Depression (additional to continuous gutter depression 'a' from above)alocal =2.00 2.00 inches Number of Unit Inlets (Grate or Curb Opening) No = 1 1 Water Depth at Flowline (outside of local depression) Ponding Depth = 6.0 6.0 inches Grate Information MINOR MAJOR Length of a Unit Grate Lo (G) =3.00 3.00 feet Warning 5 Width of a Unit Grate Wo =1.73 1.73 feet Area Opening Ratio for a Grate (typical values 0.15-0.90)Aratio =0.43 0.43 Clogging Factor for a Single Grate (typical value 0.50 - 0.70)Cf (G) =0.50 0.50 Grate Weir Coefficient (typical value 2.15 - 3.60)Cw (G) =3.30 3.30 Grate Orifice Coefficient (typical value 0.60 - 0.80)Co (G) =0.60 0.60 Curb Opening Information MINOR MAJOR Length of a Unit Curb Opening Lo (C) =3.00 3.00 feet Height of Vertical Curb Opening in Inches Hvert =6.50 6.50 inches Height of Curb Orifice Throat in Inches Hthroat =5.25 5.25 inches Angle of Throat (see USDCM Figure ST-5) Theta = 0.00 0.00 degrees Side Width for Depression Pan (typically the gutter width of 2 feet)Wp =1.00 1.00 feet Clogging Factor for a Single Curb Opening (typical value 0.10)Cf (C) =0.10 0.10 Curb Opening Weir Coefficient (typical value 2.3-3.7)Cw (C) =3.70 3.70 Curb Opening Orifice Coefficient (typical value 0.60 - 0.70)Co (C) =0.66 0.66 Low Head Performance Reduction (Calculated)MINOR MAJOR Depth for Grate Midwidth dGrate =0.451 0.451 ft Depth for Curb Opening Weir Equation dCurb =0.42 0.42 ft Combination Inlet Performance Reduction Factor for Long Inlets RFCombination =0.94 0.94 Curb Opening Performance Reduction Factor for Long Inlets RFCurb =1.00 1.00 Grated Inlet Performance Reduction Factor for Long Inlets RFGrate =0.94 0.94 MINOR MAJOR Total Inlet Interception Capacity (assumes clogged condition)Qa =3.7 3.7 cfs Inlet Capacity IS GOOD for Minor and Major Storms(>Q PEAK)Q PEAK REQUIRED =0.4 1.6 cfs Warning 5: The width of unit is greater than the gutter width. CDOT/Denver 13 Combination INLET IN A SUMP OR SAG LOCATION Version 4.06 Released August 2018 H-VertH-Curb W Lo (C) Lo (G) Wo WP CDOT/Denver 13 Combination Override Depths UD-Inlet_v4.06, Inlet B1 (Basin A3) 12/8/2020, 6:19 PM Design Information (Input)MINOR MAJOR Type of Inlet Type = Local Depression (additional to continuous gutter depression 'a' from above)alocal =2.00 2.00 inches Number of Unit Inlets (Grate or Curb Opening) No = 2 2 Water Depth at Flowline (outside of local depression) Ponding Depth = 6.0 6.0 inches Grate Information MINOR MAJOR Length of a Unit Grate Lo (G) =3.00 3.00 feet Warning 5 Width of a Unit Grate Wo =1.73 1.73 feet Area Opening Ratio for a Grate (typical values 0.15-0.90)Aratio =0.43 0.43 Clogging Factor for a Single Grate (typical value 0.50 - 0.70)Cf (G) =0.50 0.50 Grate Weir Coefficient (typical value 2.15 - 3.60)Cw (G) =3.30 3.30 Grate Orifice Coefficient (typical value 0.60 - 0.80)Co (G) =0.60 0.60 Curb Opening Information MINOR MAJOR Length of a Unit Curb Opening Lo (C) =3.00 3.00 feet Height of Vertical Curb Opening in Inches Hvert =6.50 6.50 inches Height of Curb Orifice Throat in Inches Hthroat =5.25 5.25 inches Angle of Throat (see USDCM Figure ST-5) Theta = 0.00 0.00 degrees Side Width for Depression Pan (typically the gutter width of 2 feet)Wp =1.00 1.00 feet Clogging Factor for a Single Curb Opening (typical value 0.10)Cf (C) =0.10 0.10 Curb Opening Weir Coefficient (typical value 2.3-3.7)Cw (C) =3.70 3.70 Curb Opening Orifice Coefficient (typical value 0.60 - 0.70)Co (C) =0.66 0.66 Low Head Performance Reduction (Calculated)MINOR MAJOR Depth for Grate Midwidth dGrate =0.451 0.451 ft Depth for Curb Opening Weir Equation dCurb =0.42 0.42 ft Combination Inlet Performance Reduction Factor for Long Inlets RFCombination =0.71 0.71 Curb Opening Performance Reduction Factor for Long Inlets RFCurb =1.00 1.00 Grated Inlet Performance Reduction Factor for Long Inlets RFGrate =0.71 0.71 MINOR MAJOR Total Inlet Interception Capacity (assumes clogged condition)Qa =5.6 5.6 cfs Inlet Capacity IS GOOD for Minor and Major Storms(>Q PEAK)Q PEAK REQUIRED =1.2 5.1 cfs Warning 5: The width of unit is greater than the gutter width. CDOT/Denver 13 Combination INLET IN A SUMP OR SAG LOCATION Version 4.06 Released August 2018 H-VertH-Curb W Lo (C) Lo (G) Wo WP CDOT/Denver 13 Combination Override Depths UD-Inlet_v4.06, Inlet C2-1(E) (Basin A6) 12/8/2020, 6:19 PM ST O R M L I N E A ST O R M L I N E B ST O R M L I N E C ST O R M L I N E C 2 (E A S T ) ST O R M L I N E C 2 (W E S T ) ST O R M L I N E D (E A S T ) ST O R M L I N E D (W E S T ) ST O R M L I N E E A PPENDIX C R EFERENCED M ATERIALS This unofficial copy was downloaded on Jan-27-2020 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA This unofficial copy was downloaded on Jan-27-2020 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA This unofficial copy was downloaded on Jan-27-2020 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA This unofficial copy was downloaded on Jan-27-2020 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA This unofficial copy was downloaded on Jan-27-2020 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA This unofficial copy was downloaded on Jan-27-2020 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA This unofficial copy was downloaded on Jan-27-2020 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA This unofficial copy was downloaded on Jan-27-2020 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA This unofficial copy was downloaded on Jan-27-2020 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA This unofficial copy was downloaded on Jan-27-2020 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA This unofficial copy was downloaded on Jan-27-2020 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA This unofficial copy was downloaded on Jan-27-2020 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA This unofficial copy was downloaded on Jan-27-2020 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA This unofficial copy was downloaded on Jan-27-2020 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA This unofficial copy was downloaded on Jan-27-2020 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA This unofficial copy was downloaded on Jan-27-2020 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA This unofficial copy was downloaded on Jan-27-2020 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA This unofficial copy was downloaded on Jun-17-2020 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA This unofficial copy was downloaded on Jun-17-2020 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA This unofficial copy was downloaded on Jun-17-2020 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA This unofficial copy was downloaded on Jun-17-2020 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA This unofficial copy was downloaded on Jun-17-2020 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA This unofficial copy was downloaded on Jun-17-2020 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA This unofficial copy was downloaded on Jun-17-2020 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA This unofficial copy was downloaded on Jun-17-2020 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA This unofficial copy was downloaded on Jun-17-2020 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA This unofficial copy was downloaded on Jun-17-2020 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA This unofficial copy was downloaded on Jun-17-2020 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA This unofficial copy was downloaded on Jun-17-2020 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA This unofficial copy was downloaded on Jun-17-2020 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA This unofficial copy was downloaded on Jun-17-2020 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA This unofficial copy was downloaded on Jun-17-2020 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA This unofficial copy was downloaded on Jun-17-2020 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA This unofficial copy was downloaded on Jun-17-2020 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA This unofficial copy was downloaded on Jun-17-2020 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA This unofficial copy was downloaded on Jun-17-2020 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA This unofficial copy was downloaded on Jun-17-2020 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA This unofficial copy was downloaded on Jun-17-2020 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA This unofficial copy was downloaded on Jun-17-2020 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA This unofficial copy was downloaded on Jun-17-2020 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA This unofficial copy was downloaded on Jun-17-2020 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA This unofficial copy was downloaded on Jan-27-2020 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA This unofficial copy was downloaded on Jan-27-2020 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA This unofficial copy was downloaded on Jan-27-2020 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA This unofficial copy was downloaded on Jan-27-2020 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA This unofficial copy was downloaded on Jan-27-2020 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA This unofficial copy was downloaded on Jan-27-2020 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA This unofficial copy was downloaded on Jan-27-2020 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA This unofficial copy was downloaded on Jan-27-2020 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA This unofficial copy was downloaded on Jan-27-2020 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA This unofficial copy was downloaded on Jan-27-2020 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA This unofficial copy was downloaded on Jan-27-2020 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA This unofficial copy was downloaded on Jan-27-2020 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA This unofficial copy was downloaded on Jan-27-2020 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA This unofficial copy was downloaded on Jan-27-2020 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA This unofficial copy was downloaded on Jan-27-2020 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA This unofficial copy was downloaded on Jan-27-2020 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA This unofficial copy was downloaded on Jan-27-2020 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA This unofficial copy was downloaded on Jan-27-2020 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA A PPENDIX D D RAINAGE E XHIBITS