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QUIK TRIP - PDP230010 - SUBMITTAL DOCUMENTS - ROUND 1 - DRAINAGE REPORT
PRELIMINARY DRAINAGE REPORT Quik Trip Fort Collins – 4248 Fort Collins, CO PREPARED FOR: 4705 South 129th East Avenue Tulsa, OK 74134 Project No. 0222053 Date: July 10, 2023 QuikTrip Fort Collins - 4248 Lamp Rynearson P | 1 PRELIMINARY DRAINAGE REPORT QUIKTRIP FORT COLLINS - 4248 Fort Collins, Colorado CERTIFICATION OF ENGINEER I hereby attest that this report for the preliminary drainage design for the QuikTrip Fort Collins – 4248 was prepared by me or under my direct supervision, in accordance with the provisions of the Fort Collins Stormwater Criteria Manual. I understand that the City of Fort Collins does not and will not assume liability for drainage facilities designed by others. Pat Hillyer, Registered Professional Engineer State of Colorado Registration No. 57661 QuikTrip Fort Collins - 4248 Lamp Rynearson P | 2 I. Table of Contents I. Introduction ........................................................................................................................................................................................ 4 Site Location ....................................................................................................................................... 4 Property Description ............................................................................................................................ 4 Floodplain ............................................................................................................................................ 5 II. Historic Drainage .............................................................................................................................................................................. 5 Major Basin Description ....................................................................................................................... 5 Sub-Basin Description ......................................................................................................................... 5 III. Drainage Design Criteria ................................................................................................................................................................ 7 Regulations/Development Criteria ....................................................................................................... 7 Four Step Process ............................................................................................................................... 7 Hydrologic Criteria ............................................................................................................................... 8 Hydraulic Criteria ................................................................................................................................. 8 LID Systems, Stormwater Quality & Erosion Control ........................................................................... 8 IV. Drainage Facility Design ............................................................................................................................................................ 9 General Concept ................................................................................................................................. 9 Specific Details .................................................................................................................................. 10 Full Spectrum Detention, EURV, and WQCV .................................................................................... 12 V. Conclusion ........................................................................................................................................................................................ 14 Compliance with Standards ............................................................................................................... 14 Drainage Concept ............................................................................................................................. 14 VI. References .................................................................................................................................................................................... 14 QuikTrip Fort Collins - 4248 Lamp Rynearson P | 3 Appendices Appendix A 1. Develop Conditions Drainage Plan 2. Gateway to Prospect (By Northern Engineering) Master Drainage Plan Appendix B 1. NRCS Soils Data & Map 2. Floodplain Information 3. City of Fort Collins IDF Table 4. Recommended Imperviousness Table 5. City of Fort Collins Reference Material 6. Referenced pages from Gateway to Prospect (By Northern Engineering) Appendix C 1. Rational Method Results 2. Detention Basin Calculations 3. Low Impact Development Calculations (Rain Gardens & Bio Swale) 4. Detention Pond Spillway Calculation QuikTrip Fort Collins - 4248 Lamp Rynearson P | 4 I. Introduction This drainage report contains the details for the overall drainage design for the QuikTrip Fort Collins – 4248 development. The report also includes information on the historic drainage patterns for the site and outlines the previous drainage design information provided in “Final Drainage Report Gateway to Prospect” (hereon referred to as the “Master Plan”, prepared by Northern Engineering, Inc. in August of 2022. Site Location This proposed development is located in the southeast ¼ of the southeast ¼ of Section 16, Township 7 North, Range 68 West of the 6th P.M., County of Larimer, City of Fort Collins, Colorado. The property is located within proposed Gateway at Prospect Subdivision which is generally located at the northwest corner of East Prospect Road and I-25 and is comprised of approximately 2.2 acres of land zoned for General Commercial uses. The site is situated along the existing I-25 west frontage road and east of the existing Boxelder Estates 1st Replat. The existing lot does not have any stormwater or water quality facilities. Figure 1 – Vicinity Map Property Description The QuikTrip Fort Collins – 4248 development, is approximately 2.2 acres, not including the existing frontage road. The development proposes adding a QuikTrip convenience store as well as realigning the I-25 West Frontage Road. In the future, this area will consist of low-density and medium-density mixed-use districts and a small urban estate district, commercial districts, and an employment district. QuikTrip Fort Collins - 4248 Lamp Rynearson P | 5 The proposed development site is in the City of Fort Collins Boxelder Creek/Cooper Slough Basin. Detention and water quality requirements for each future development will be laid out within this report. Future developments will still be responsible for calculating and implementing LID requirements set forth in the City of Fort Collins Stormwater Criteria Manual. According to the NRCS website, the site consists entirely of Type C soils. According to the NRCS, the Type C soils are classified as Nunn clay Loam and Nunn clay loam, wet. See Appendix B for NRCS soils data. Existing ground cover and vegetation type primary consists of native grasses and shrubs. Floodplain The subject property is not located in a FEMA floodplain. However, a section of the Gateway at Prospect project, which QuikTrip Fort Collins – 4248 is located within, is located in a FEAM floodplain and will be pursuing a CLOMR/LOMR with this project. This CLOMR/LOMR will revise the floodplain and floodway along the Boxelder Creek within the limits of this project. This CLOMR/LOMR will effectively limit the extent of the floodplain and allow for the installation of a bridge over Boxelder Creek. See appendix B for FEMA floodplain map. II. Historic Drainage Major Basin Description QuikTrip Fort Collins – 4248 is located within the Boxelder Creek/Cooper Slough Basin. Boxelder Creek/Cooper Slough Basin encompasses 265 square miles beginning north of the Colorado/Wyoming border and extending southward into east Fort Collins, ending at the Cache La Poudre River. Improvements along the Boxelder Creek were recently constructed and detailed in the LOMR case number 17- 08-1354P. A 100-year overflow channel and box culverts under Prospect Road were constructed as a part of that project. Sub-Basin Description Historically the property generally drains south and towards the center of the property where the Boxelder Creek sits. The 100-year overflow channel is situated within the Gateway at Prospect site but not the QuikTrip Fort Collins – 4248 site. In normal flowing conditions, the Boxelder Creek flows within its typical channel and heads south through a newly constructed box culvert under Prospect Road. Boxelder Creek continues south until it discharges into the Poudre River. During the 100-year event, an emergency overflow weir will reroute runoff to the west of the typical creek and into the overflow channel. Once runoff is routed to the overflow channel, it is conveyed south through a separate box culvert under Prospect Road. From there, the runoff will remain in the overflow channel until it enters the Poudre River. In 2018 Ayers Associates, as a part of the previous LOMR effort, created a SWMM model that modeled existing flows for the 2-year, 5-year, 10-year, 25-year, 50-year, and 100-year events of the Boxelder Creek/Cooper Slough Basin with the proposed Boxelder Creek improvements. QuikTrip Fort Collins – 4248 property falls within this model. This model was used to verify downstream infrastructure will not be impacted by future developments within the Gateway at Prospect or QuikTrip Fort Collins – 4248 property. QuikTrip Fort Collins - 4248 Lamp Rynearson P | 6 Figure 2 - Snapshot of Existing Ayers Associates SWMM Model There are some important Nodes to take note of within this model. Node 884 is the closest upstream node before Gateway at Prospect discharging into the Boxelder Creek. Divider 885 represents the previously described emergency overflow weir. Nodes 886 and 887 are the downstream nodes in both the normal conveyance path and the emergency overflow channel. A more in-depth explanation can be found later in the report. Table 1 - Flowrates for Project Specific Nodes via QuikTrip Fort Collins – 4248 is located toward the end of the Boxelder Creek/Cooper Slough Basin. Traditionally new developments within Fort Collins must detain the difference between the 100-year developed inflow rate and the historic 2-year release rate. However, this location is optimal for the use of full spectrum detention. The City of Fort Collins has approved the use of full spectrum detention with the caveat that it can be shown there are no “substantial” increases in flow to Boxelder Creek. The detention ponds adjacent to Boxelder Creek have been sized for the ultimate condition. This is an attempt to limit disturbance within the floodplain and natural habitat buffer zone in the future. All future developments must follow Fort Collins Stormwater Criteria Manual for LID sizing and implementation. A full-size copy of the Proposed Drainage Exhibit can be found in Appendix A at the end of this report. This Proposed Drainage Exhibit represents the final condition. SWMM ID Ayers Associate Boxelder Basin Model 100-YR Flow Rates (cfs) Node 884 3377.99 Divider 885 3377.89 Node 886 950.98 Node 887 2426.9 QuikTrip Fort Collins - 4248 Lamp Rynearson P | 7 III. Drainage Design Criteria Regulations/Development Criteria Mile High Flood District’s Urban Storm Drainage Criteria Manual (USDCM), and the City of Fort Collins Storm Criteria Manual, as well as good engineering practices have been used to calculate the stormwater runoff to design the stormwater facilities for this site. As previously mentioned, “Gateway to Prospect Final Drainage Report” prepared by Northern Engineering in August of 2022 was referenced. This final drainage report was referenced to assure the proposed development meets the overall drainage intent as laid out by the City of Fort Collins. QuikTrip Fort Collins – 4248 proposes utilizing full spectrum for this site. By utilizing full spectrum, due to the proximity to Boxelder Creek, QuikTrip Fort Collins – 4248 will be able to “beat the peak” of the existing condition within the Boxelder Creek/Cooper Slough Basin. Therefore, it is expected the QuikTrip Fort Collins – 4248 project will not cause damage to downstream infrastructure and/or cause more maintenance than historical conditions. Full spectrum guidelines laid out by Mile High Flood Control District were followed. Four Step Process The overall stormwater management strategy employed with the QuikTrip Fort Collins – 4248 project utilizes the “Four Step Process” to minimize adverse impacts of urbanization on receiving waters. The following describes how the proposed development has incorporated each step. a) Step 1 – Employ Runoff Reduction Practices QuikTrip Fort Collins – 4248 will be reducing peak flow rates by 10% of the historic value via full spectrum. Full spectrum detention is designed to address two limitations of traditional detention. First, it is focused on controlling peak discharges over the full spectrum of runoff events from small, frequent storms up to the 100-year storm event. Second, full spectrum detention facilities produce outflow hydrographs that, other than a small release rate of the excess urban runoff volume (EURV), replicate the shape of predevelopment hydrographs. Full spectrum detention modeling shows a reduction of urban runoff peaks to levels similar to predevelopment conditions over an entire watershed, even with multiple independent detention facilities. For a thorough, in-depth explanation of full spectrum, please refer to Volume 2, Chapter 12 of the Urban Drainage Stormwater Criteria Manual published by the Mile High Flood Control District. QuikTrip Fort Collins – 4248 development will be responsible for implementing Low Impact Development (LID) measures. These measures can include rain gardens, grass buffers, underground infiltration and detention basins, permeable pavers, etc. These measures effectively work to reduce runoff from developed areas. b) Step 2 – Implement BMPs that Provide a Water Quality Capture Volume (WQCV) with Slow Release Water quality will be provided via LID measures and extended detention per Mile High Flood Control District standards for full spectrum detention. Full spectrum water quality capture volume (WQCV) utilizes the same criteria the Fort Collins Stormwater Criteria Manual uses. Additionally, the lower portion of volume in a full spectrum detention facility is designed to capture and slowly release the excess urban runoff volume (EURV). The EURV is the difference between the developed condition runoff volume and the predevelopment volume. The EURV is typically two to three times the WQCV. Furthermore, stormwater quality will also occur by routing the on-site drainage through multiple LID Systems and constructed improvements such as rain gardens and bioswales located within open areas of the site. QuikTrip Fort Collins - 4248 Lamp Rynearson P | 8 c) Step 3 – Stabilize Drainageways By utilizing a combination of full spectrum detention and the resulting “beat the peak” model, the peak discharge from the QuikTrip Fort Collins – 4248 project will be passed before the peak of the creek. As such, the peak discharge from the QuikTrip Fort Collins – 4248 project will not be compounded with peak flow in the creek. Also, it should be noted that the proposed releasing of stormwater into an outfall will be designed by others. d) Step 4 – Implement Site Specific and Other Source Control BMPs Stormwater quality will be managed on-site during construction with the use of silt fencing, vehicle tracking devices and inlet/outlet protection devices. Long-term stormwater quality will occur by routing the on-site drainage through multiple LID Systems and constructed improvements such as rain gardens and bioswales located within open areas. A sand/oil separator is also proposed to treat any oil/gas contaminates that maybe captured by stormwater. Hydrologic Criteria The 2-year (minor) and 100-year (major) design storms were used for the developed discharge, as indicated in Chapter 5, Section 1.4 of the City of Fort Collins Stormwater Criteria Manual. The 10-year event was also computed for comparison purposes only. The City of Fort Collins Intensity-Duration-Frequency curves & tables were used to obtain rainfall data for each storm specified located in Chapter 5, Section 3. As the site is less than 5 acres, the Rational Method (MHFD’s UD-Rational v.2.00 and in accordance with City of Fort Collins Stormwater Criteria Manual) has been used to calculate the developed stormwater runoff for the purpose of sizing inlets, swales, storm pipes, LID structures and detention pond. Full spectrum detention has been utilized for detention storage calculations. Impervious values for each basin were calculated from the expected uses and taken from Table 6-3 in Chapter 6 of the UDFCD Volume 1, Management, Hydrology, and Hydraulics. Rational Method “C” values were taken from Table 3.2-2. Surface Type - Runoff Coefficients and Table 3.2-3. Frequency Adjustment Factors of the City of Fort Collins Stormwater Criteria Manual. Time of concentration values were also obtained from following the City of Fort Collins Stormwater Criteria Manual by calculating overland flow time and channelized flow time to ultimately obtain total time of concentration. Hydraulic Criteria Stormwater structures (inlets, swales, storm pipes, LID structures, detention pond) have been designed for the proposed convenience store stormwater infrastructure. These have been designed using techniques developed or adopted by the City of Fort Collins and the storm sewer systems were designed to capture and convey the minor events. LID Systems, Stormwater Quality & Erosion Control Stormwater quality will be managed on-site during construction with the use of silt fencing, vehicle tracking devices and inlet/outlet protection devices. Long-term stormwater quality will occur by routing the on-site drainage through multiple LID Systems and constructed improvements such as rain gardens and bioswales located within open areas. A sand/oil separator is also proposed to treat any oil/gas contaminates that maybe captured by stormwater. Additional treatment will occur by routing runoff into a water quality/detention pond and releasing it at an attenuated rate over an extended period of time. The outlet structures for the ponds have been designed to account for a 40-hour water quality capture volume with a 100-year emergency spillway draining to a storm sewer that drains to Boxelder Creek or existing drainage way. All erosion control plans & list of materials will be provided with final plans. QuikTrip Fort Collins - 4248 Lamp Rynearson P | 9 IV. Drainage Facility Design General Concept The proposed development has been divided into 10 on-site sub-basins and 2 off-site sub-basins, each representing a specific discharge point. The on-site sub-basins for the proposed development were determined and routed to establish key stormwater discharge points within the development. A Detention Pond (Full Spectrum) has been proposed to treat and mitigate flows from the developed site as well as the off-site basins. This pond has been placed in a strategic location in the QuikTrip Fort Collins – 4248 development and is aimed at collecting, attenuating, and releasing flows that follow existing flow patterns and match the constraints as defined by the Mile High Flood District. Flows will be conveyed to the full spectrum detention pond either through the proposed stormwater system or through the roadway capacity. 75% of the newly added or modified impervious area will be treated by Low Impact Development (LID) techniques. These LID techniques will include raingardens and bioswales. All offsite flows will be treated by a LID rain garden or bioswale. Table - 2 Total on Site Impervious Summary Table Basin ID Total Area Impervious Area Percent of Impervious Area SF AC SF AC A1* 5312 0.12 5312 0.122 100% A2* 7287 0.17 7287 0.167 100% A3 19102 0.44 18758 0.431 98% A4* 5997 0.13 5397 0.124 90% A5* 6186 0.14 5567 0.128 90% A6* 3957 0.09 1482 0.034 37% A7* 17857 0.41 7175 0.165 40% A8 26115 0.60 0 0.000 0% B1 1089 0.03 0 0.000 0% B2 1736 0.04 0 0.000 0% C1* 48281 1.11 28850 0.662 60% C2* 3679 0.08 3679 0.084 100% Total: 146598 3.36 83507 1.917 57% Total LID Basins: 98556 2.254862 64749 1.4864 Percent of Impervious Area to be treated by LID 78% Note 1: * basin will be treated by LID structures. Note 2: Offsite basins C1 and C2 will be treated by LID structures. QuikTrip Fort Collins - 4248 Lamp Rynearson P | 10 Specific Details Off-Site Basins There are two off-site basins that will influence this QuikTrip development. Offsite basins are delineated as “C” Basins as described below. Basin C1 (1.11 Acres – 60% Imperviousness Area) produces developed flows of 1.69 cfs during the 2-year storm and 7.39 cfs during the 100-year storm. Basin C1 consists of the east half of the frontage road and right- of-way. Flow will start approximately 650 feet to the north and travel south to curb cut. Once flows enter the curb cut, they will enter a 2’ wide concrete flume and travel into a rain garden located on the QuikTrip site. From there, flows from Basin C1 will be treated by Rain Garden B and enter the detention pond via underground drains or overtopping of the raingarden. Basin C2 (0.08 Acres – 100% Imperviousness Area) produces developed flows of 0.21 cfs during the 2-year storm and 0.78 cfs during the 100-year storm. Basin C2 consists entirely of the north half of the private access road north of the building. Flow will start approximately 300 feet to the west and travel east to the end of the proposed access road. Once flows exits the access road, they will enter a proposed bioswale. From there Basin C2 flows will be treated by the bioswale and enter the detention pond via by the swale or underground drain. On-Site Basins There are 10 on-site basins that this development will consist of. They are broken up into two descriptors, “A” basins and “B” basins. There will be 8 “A” basins which are basins that are captured and remain on site till they are treated and released. These “A” Basin flows will be treated via LID techniques or by detention water quality and are ultimately released through the detention pond. Furthermore, there will be 2 “B” basins which are historical basins that are not captured or treated and exit the site. These basins disturb a small area of the site and do not increase imperviousness. A - Basins There are 8 sub-basins within this grouping, Basin A1 – A8. These sub-basins include areas designated as landscaping, drives, parking, sidewalks and roofs. These basins make up the majority of the site and all basins within this grouping ultimately discharge into the full spectrum detention pond. Basin A1 (0.12 Acres – 100% Imperviousness Area) produces developed flows of 0.32 cfs during the 2-year storm and 1.16 cfs during the 100-year storm. Basin A1 consists of the roof of the proposed QuikTrip building. Flows will enter roof drains and will be transported underground to a rain garden via storm sewer. From there, flows from Bains A1 will be treated by Rain Garden A and enter the detention pond via underground drains or overtopping of the raingarden. Basin A2 (0.17 Acres – 100% Imperviousness Area) produces developed flows of 0.45 cfs during the 2-year storm and 1.65 cfs during the 100-year storm. Basin A2 consists of the roof of the proposed QuikTrip canopy. Flows will enter roof drains and will be transported underground to the top of the bioswale located on the east side of the site. From there Basin A2 flow will be treated by the bioswale and enter the detention pond via by the swale or underground drain. Basin A3 (0.44 Acres – 98% Imperviousness Area) produces developed flows of 1.14 cfs during the 2-year storm and 4.27 cfs during the 100-year storm. Basin A3 consists of mostly of the parking & the drive aisle around the canopy. This area also contains the fuel tanks. Due to this area being a source of contamination, from gasoline, flows from Basin A3 will enter a curb inlet and then enter directly into a sand oil separator. Any contaminates in the stormwater will be filtered out in the sand oil separator. Once the stormwater in filtered through the sand/oil separator, it will enter the detention pond via storm pipe. QuikTrip Fort Collins - 4248 Lamp Rynearson P | 11 Basin A4 (0.14 Acres – 90% Imperviousness Area) produces developed flows of 0.31 cfs during the 2-year storm and 1.26 cfs during the 100-year storm. Basin A4 consists of half of the south parking, drive aisle and proposed rain garden. Flows from Basin A4 will sheet flow across the parking and drive aisle and will enter a curb cut and flow into a proposed rain garden. From there, flows from Basin A4 will be treated by Rain Garden A and enter the detention pond via underground drains or overtopping of the raingarden. Basin A5 (0.14 Acres – 90% Imperviousness Area) produces developed flows of 0.32 cfs during the 2-year storm and 1.36 cfs during the 100-year storm. Basin A5 consists of half of the south parking, drive aisle and proposed rain garden. Flows from Basin A5 will sheet flow across the parking and drive aisle and will enter a curb cut and flow into a proposed rain garden. From there, flows from Basin A5 will be treated by Rain Garden A and enter the detention pond via underground drain or overtopping of the raingarden. Basin A6 (0.09 Acres – 37% Imperviousness Area) produces developed flows of 0.13 cfs during the 2-year storm and 0.57 cfs during the 100-year storm. Basin A6 consists of land scaping and a building patio on the west edge of the property next to the frontage road right-of-way. Flows from Basin A6 generally flow west and into a proposed drainage pan. Once flows enter the drainage pan, they are transported south and into a proposed rain garden. From there, flows from Basin A6 will be treated by Rain Garden A and enter the detention pond via underground drains or overtopping of the raingarden. Basin A7 (0.41 Acres – 40% Imperviousness Area) produces developed flows of 0.60 cfs during the 2-year storm and 2.63 cfs during the 100-year storm. Basin A7 consists of mostly of landscaping, sidewalks, south half of the private access road and bioswale. Flows from Basin A7 will start on the access road and travel east to the bioswale. From there, flow from Basin A7 will be treated by the bioswale, travel south, and enter the detention pond via by the swale or underground drain or overtopping of the raingarden. Basin A8 (0.60 Acres – 0% Imperviousness Area) produces developed flows of 0.36 cfs during the 2-year storm and 1.56 cfs during the 100-year storm. Basin A8 consists entirely of the proposed detention pond and rain garden B. Basin A8 is located on the south end of the property at is lowest elevation. This basin contains the water storage, detention pond, facility. All A-Basins (onsite) and C-Basins (offsite) flows will eventually end up in Basin A8. Flows that enter Basin A8 will be temporarily stored in the detention pond and released through an outlet structure at designated historic rates. B- Basins There are 2 sub-basins within this grouping, Basin B1 & B2. These sub-basins include are historical basins that are not captured or treated and exit the site. These basins disturb a small area of the site and do not increase imperviousness. Basin B1 (0.03 Acres – 0% Imperviousness Area) produces a developed flow of 0.12 cfs during the 100-year Rational Method Results. Basin B1 consists of the east edge of the outer berm of the detention pond. Runoff from this basin will travel south offsite as historically done before development. Basin B2 (0.04 Acres – 0% Imperviousness Area) produces a developed flow of 0.16 cfs during the 100-year Rational Method Results. Basin B2 consists of the south edge of the outer berm of the detention pond. Runoff from this basin will travel south offsite as historically done before development. QuikTrip Fort Collins - 4248 Lamp Rynearson P | 12 Table 3 – Rational Method Summary EXISTING BASIN CALCULATIONS DESIGN POINT BASIN AREA Imperviousness % tc2 tc100 C2 C100 Q2 Q100 E1 E1 2.17 2.0% 12.30 12.30 0.20 0.25 0.88 3.85 Total Affected Site 2.17 2.0% 12.30 12.30 0.20 0.25 0.88 3.85 DEVELOPED BASIN CALCULATIONS DESIGN POINT BASIN AREA Imperviousness % tc2 tc100 C2 C100 Q2 Q100 A BASINS A1 A1 0.12 90% 5.0 5.0 0.95 1.00 0.32 1.16 A2 A2 0.17 90% 5.0 5.0 0.95 1.00 0.45 1.65 A3 A3 0.44 98% 5.0 5.0 0.93 1.00 1.14 4.27 A4 A4 0.13 79% 5.0 5.0 0.86 1.00 0.31 1.26 A5 A5 0.14 85% 5.0 5.0 0.81 1.00 0.32 1.36 A6 A6 0.09 35% 5.5 5.0 0.52 0.65 0.13 0.57 A7 A7 0.41 43% 6.8 6.1 0.56 0.70 0.60 2.63 A8 A8 0.60 2% 11.6 11.0 0.28 0.35 0.36 1.56 Total A 2.10 54% 9.7 8.6 0.65 0.81 3.54 15.39 B BASINS B1 B1 0.03 2% 5.0 5.0 0.35 0.44 0.03 0.13 B2 B2 0.04 2% 5.0 5.0 0.35 0.44 0.04 0.16 Total B 0.07 2% 5.8 5.1 0.35 0.44 0.06 0.28 C BASINS C1 C1 1.11 60% 11.5 9.1 0.66 0.83 1.69 7.39 C2 C2 0.13 100% 5.0 5.0 0.95 1.00 0.21 0.78 Total C 1.24 64% 11.0 8.5 0.69 0.87 2.02 8.87 ENTIRE SITE Total 3.41 57% 11.6 9.2 0.66 0.82 5.08 22.34 A+B Basins (Onsite) 2.17 53% 7.2 6.2 0.77 0.96 4.37 19.22 A+C Basins (Pond) 3.34 58% 11.5 9.1 0.66 0.83 4.99 21.70 Full Spectrum Detention, EURV, and WQCV QuikTrip Fort Collins – 4248 is located near the end of the Boxelder Creek/Cooper Slough Basin and will be ultimately discharging into Boxelder Creek. To maintain stabilization full spectrum detention was utilized to size detention pond and release rates. The rationale behind this is to “beat the peak” and have the site drained before the peak flowrates within Boxelder Creek occur. QuikTrip Fort Collins – 4248 proposes providing 100-year detention, detaining the EURV, and utilizing extended detention for water quality. However, storm lines have been sized for ultimate conditions unless otherwise stated. All on and offsite flows (excluding B-Basins) are captured, detained and attenuated to meet the City’s release rate of 90% of the 100-year pre-developed flow, per MHFD and full spectrum detention. This regulation is in accordance with City of Fort Collins Full Spectrum Detention release rate. To facilitate this flow release, the pond QuikTrip Fort Collins - 4248 Lamp Rynearson P | 13 has an outlet structure that will drain the WQCV, the 2-year and 100-year storms in the designated times set out by the current State water laws. Emergency spillway was sized to allow any flows in excess of the 100-year to safely pass downstream. 1 foot of freeboard was provided above the crest of the spillway to aid in the safe conveyance of excess flows. See Appendix B for more information. Maintenance of these ponds must be completed regularly and include items such as regular mowing in the growing season, annual inspection and cleaning of the outlet structure. The pond should be inspected after heavy rain where significant ponding has occurred. Table - 4 Detention and Water Quality Pond Summary Description Proposed Design Site Impervious Percentage 57% Site Area to Pond (ac) 3.29 Required Pond Volume (ac-ft) 0.429 Pond Release (Predeveloped) (cfs) 5.0 Pond Release (Proposed) (cfs) 4.3 Water Quality Capture Volume (ac-ft) 0.065 Bottom Length of Overflow Spillway (ft) 18.5 Depth of Flow over Spillway - 100-year event (ft) 0.50 100-yr Water Surface Elevation (ft) 4901.90 Spillway Elevation (ft) 4903.00 Top of Pond Elevation (ft) 4904.00 Furthermore, this site is situated in a portion of an already delineated design basin outlined in the Overall Drainage Report for Gateway at Prospect Overall Development Plan, by Northern Engineering, dated August 24, 2022. In this drainage report by Northern Engineering, the design basin is 19.58 acres and includes the frontage road right-of-way (Basin H1 & H2). QuikTrip Fort Collins site makes up 3.36 acres of Northern Engineering’s initial basin and also includes the frontage road right-of-way. The initial estimates of the 19.58 acre basin was 80% watershed imperviousness for any future site which yielded a 27.7 cfs 100-year developed runoff for Basin H. This site has been approved for full spectrum detention, which means the pond maximum release rate can be 90% of the 100-year predeveloped release rate. The maximum 100-year release rate of Northern Engineering’s is to be 24.9 cfs. QuikTrip Fort Collins - 4248 Lamp Rynearson P | 14 Currently, QuikTrip Fort Collins pond parameters is set to have an 57% watershed imperviousness which yields a predeveloped 100-year release rate of 5.0 cfs. While following the criteria of full spectrum detention, the maximum release rate of the 100-year storm is 4.5 cfs. Northern Engineering will be responsible for designing and developing the rest of their initial basin (H1) from their Drainage Report for Gateway at Prospect Overall Development Plan. Northern Engineering will be designing a detention pond adjacent to the QuikTrip Fort Collins site to treat future runoff. Due to the geometry and utility design of the site, QuikTrip will be designing a storm sewer line for Northern to outlet their future detention pond. This storm sewer will run through the QuikTrip Fort Collins site connect to the outlet pipe of the QuikTrip detention pond. See Drainage Report for Gateway at Prospect Overall Development Plan, by Northern Engineering, dated August 24, 2022 for full details of the report and Pond H. V. Conclusion Compliance with Standards The drainage design proposed with the QuikTrip Fort Collins – 4248 project does not comply with the City of Fort Collins’ Stormwater Criteria Manual but does meet the Mile High Flood Control District Criteria Manual as coordinated with the overall development plan, this site is under the parameters of Full Spectrum Detention which this site was given a variance to adhere to by the City of Fort Collins. The drainage design proposed with the QuikTrip Fort Collins – 4248 project complies with the City of Fort Collins’ Master Drainage Plan for the Boxelder and Cooper Slough Basin. Drainage Concept The drainage design proposed with this project will effectively limit potential damage associated with its stormwater runoff. QuikTrip Fort Collins utilized full spectrum detention as a mechanism to “beat the peak” of Boxelder Creek. The proposed QuikTrip Fort Collins development will not impact the Gateway at Prospect Final Drainage Plan recommendations for the Boxelder and Cooper Slough major drainage basin. VI. References 1. City of Fort Collins Landscape Design Guidelines for Stormwater and Detention Facilities, November 5, 2009, BHA Design, Inc. with City of Fort Collins Utility Services. 2. Fort Collins Stormwater Criteria Manual, City of Fort Collins, Colorado, as adopted by Ordinance No. 174, 2011, and referenced in Section 26-500 (c) of the City of Fort Collins Municipal Code. 3. Larimer County Urban Area Street Standards, Adopted January 2, 2001, Repealed and Reenacted, Effective October 1, 2002, Repealed and Reenacted, Effective April 1, 2007. 4. Soils Resource Report for Larimer County Area, Colorado, Natural Resources Conservation Service, United States Department of Agriculture. 5. Urban Storm Drainage Criteria Manual, Volumes 1-3, Mile High Flood District, Wright-McLaughlin Engineers, Denver, Colorado, Revised September 2017. 6. SWMM Analysis for the Boxelder and Cooper Slough Major Basin, Ayers Associates, Fort Collins, Colorado, 2018. 7. Overall Drainage Report for Gateway at Prospect Overall Development Plan, by Stephanie Thomas at Northern Engineering, August 24, 2022. Appendix A Maps SUBMERGEDPUMP15K UNLEADED (10'Ø)ANNULARSUBMERGEDPUMP15K UNLEADED (10'Ø)ANNULARSUBMERGEDPUMP15K PRODUCT X (10'Ø)ANNULARSUBMERGEDPUMP15K PREMIUM (10'Ø)ANNULARSUBMERGEDPUMPVAPORFILL15K DIESEL (10'Ø)ANNULARVAPORFILLVAPORFILLVAPORFILLVAPORFILLGREASE INTERCEPTOR(RE: CIVIL FOR EXACT LOCATION.)(TEST WELL)WG3SE (P-113)STORE NO.: 42485,312 S.F.BLDG. HT.= 20'-0"ICE KIOSKVAULTONLYGREASE INTERCEPTOR (RE: CIVIL FOR EXACT LOCATION.) (TEST WELL)WG3SE (P-113)STORE NO.: 42485,312 S.F.BLDG. HT.= 20'-0"YIELDYIELDYIELD 6POST DEVELOPED MAPN020204010FeetQuikTrip No.ASHEET TITLE:SHEET NUMBER:DIVISION:DESIGNED BY:1© COPYRIGHT QUIKTRIP CORPORATION 2011ANY UNAUTHORIZED USE, REPRODUCTION,PUBLICATION, DISTRIBUTION, OR SALE INWHOLE OR IN PART, IS STRICTLY FORBIDDEN.ORIGINAL ISSUE DATE:PROTOTYPE:VERSION:PROJECT NO.:DRAWN BY:REVIEWED BY:REV DATE DESCRIPTIONBC DEFGHJKLMNPQABCDEFGHJKLMNPQ23456789101112131415123456789101112131415QuikTrip No.ASHEET TITLE:SHEET NUMBER:DIVISION:DESIGNED BY:1© COPYRIGHT QUIKTRIP CORPORATION 2011ANY UNAUTHORIZED USE, REPRODUCTION,PUBLICATION, DISTRIBUTION, OR SALE INWHOLE OR IN PART, IS STRICTLY FORBIDDEN.ORIGINAL ISSUE DATE:PROTOTYPE:VERSION:DRAWN BY:REVIEWED BY:REV DATE DESCRIPTIONBC DEFGHJKLMNPQABCDEFGHJKLMNPQ234567891011121314151234567891011121314154248 NORTHWEST CORNER OF E PROSPECT RD & I25 FORT COLLINS, CO 022205310/27/2022 P-110COLORADO001DASDASMAPN020204010Feet X XXXXXXXXXXXXXX/ / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / /FO FO XXXXX X XX X X X X X XXXX X XXX X XXXXXXXXXXXXXXXOHE/ / / / / / / // / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / /XXX XXTTOH E OH E OH E OH E OHE OHE OHE OHE OHE OHE OHE OHE OHE OHE OHE OHE OHE OHE OHE OHEX10" SS 10" SS 10" SSE ETT/ / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / /TTFOFOIFOFOTT SVAULTELECTCONTROLIRRVAULT ELECT SV.P.GASTESTSTAVAULTELECT STESTSTAMHXXX/ / / / / / / /X/ / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / /XGASGASGASCONTROLIRRCONTROLIRR F.O.F.O.F.O.ELECELECELECELECELECELECELECELECELECELECVAULTELECVAULTELECVAULTELECVAULTELECACSH2OH2OWTF ESH2OH2OWH2OH2OWELECFESVAULTELECVAUL TELEC TRAFF I C VAUL T EVAUL TELEC TRAFF I C VAUL T ELEC H2OHYD T ST ST ST SVAUL TELEC ELEC VAULTELEC VAULTELECS FESDSX XTOHUOHUOHUOHUOHUOHUOHUSS12" WFESDF ESWWH2OH2OH2OH2OHYDWST12" WA1B1C1E1G1H1D1D2F3C2E2BOX1H2PUD1e2h2b1INTERIM POND BPOND CINTERIM POND HPOND EOWNER:ANDERSONKENNTH E &JULIE ANNOWNER:DEADMONDLARRY L &NANCY KOWNER: CULBERTSON DAVID M OWNER: SEASTAR LIMITEDPARTNERSHIPOWNER:DESELMSROBERT A &K DENISEOWNER: 1303FRONTAGEHOLDINGS LLCOWNER:GLANZTHOMASJ/LAURA POWNER:MOODYMARILYNJOANNEOWNER:WHITEWESLEY RANGELA MOWNER: BADECARLA MOWNER:K AND MCOMPANYOWNER:BOARD OF GOVERNORSCSU SYSTEMOWNER:NORMANDINKIM WOWNER:JORDANDAVID WOWNER:SILVERTIPREALTY LLCOWNER: HIXONTIMOTHY ROWNER: 913SMITHFIELDLLCOWNER: R WPROPERTIESOWNER:AMERIGASPROPANE LPOWNER:SCHNORRGARY L TRUSTOWNER: CTENTERPRISESLLCOWNER: 901HOLDINGCOMPANY LLPOWNER: DAKAPROPERTIES LLCOWNER: FORNEYINDUSTRIES INCOWNER: 3824CANAL LLCOWNER: 3800CANAL DR LLCOWNER: AMERICANBUILDERS ANDCONTRACTORSOWNER: CANALHOLDINGS LLCOWNER: BALLAINVESTMENTS LLCOWNER: RASSHOLDINGS LLCOWNER: RASSHOLDINGS LLCOWNER:DEANANDREW GOWNER: BALDWINTHOMASR/JANELLE ROWNER: CROISSANTPETER AOWNER: SLATEROBERT STEPHENOWNER: SHEAFORSHERYLOWNER: BEITZMAYNARDL/CALISTA K OWNER: SLATEROBERT STEPHENOWNER: MARTINEZRONALD A/LINDAM/SHANE MM/CAROLINA GOWNER: USMOBILE MODULAROWNER: USMODULARSALES COOWNER:AMERIGASPROPANE LPOWNER: SOUKUPREED M/CATHARINE KOWNER: COOPERSLEWOPENSPACE ASSNOWNER: 3445KENWOOD DR LLCOWNER: SMITHMACKENZIE ROWNER: SULLIVANSHERI SUE OWNER: BACADAVID/LUCIE IOWNER: GRIEGOPATRICIA J TRUSTOWNER: SECORRAYMOND D/ANN DOWNER:RAINSBERGERNICHOLAS J OWNER: ROGERSROY D/SHARON SOWNER: OAKESFAMILY TRUSTOWNER: NEWTONGERRITT B OWNER: MCNEALSTEPHEN WOWNER: GEILENKIRCHENGLEN JOWNER: WERTHGAIL ROWNER: LUNDEERIK/LUCILEOWNER: PIOTROWSKIPETER MARKOWNER:DAVIDSON REEDOWNER: MOWERYDEVELOPMENTLLCOWNER: 1303FRONTAGEHOLDINGS LLCOWNE R : 1 3 0 3 FRON T A G E HOLDI N G S L L CSTREET BSTREET EFRONTAGE ROADSWFRONTAGE RDTEMPORARYSWALEEXISTING BOXCULVERTSEXISTING BOXCULVERTSFRONTAGE ROAD B O X E L D E R C R E E K BOXELDER CREEKNATURAL HABITATBUFFER ZONETRACT BFUTURE DEVELOPMENTTRACT DFUTURE DEVELOPMENTTRACT GFUTURE DEVELOPMENTNODE 887(PER AYERS ASSOCIATESSWMM MODEL)NODE 886(PER AYERS ASSOCIATESSWMM MODEL)BOXELDER CREEK100-YR OVERFLOWCHANNELCACHE LA POUDRE RIVER INLETPROPOSED 100-YRFLOODPLAINF1F2f20 . 3%POND FPROSPECT ROADPOND GIRRIGATION PONDSTORM DRAIN LINE ASEE SHEET ST1STORM DRAIN LINE BSEE SHEET ST1STORM DRAIN LINE CSEE SHEET ST1STORM DRAIN LINE DSEE SHEET ST2STORM DRAIN LINE ESEE SHEET ST3STORM DRAIN LINE FSEE SHEET ST3STORM DRAIN LINE GSEE SHEET ST4STORM DRAIN LINE HSEE SHEET ST4STORM DRAIN LINE ISEE SHEET ST4STORM DRAIN LINE JSEE SHEET ST4INLET A3INLET A2OUTLET B2OUTLET C6INLET D5INLET D3OUTLET E3INLET F2INLET F3OUTLET I2d2d1h1e1f1STREET D1.1%0.9%4.9%5.6%2.1%2.1%BOX2OUTLET H2OUTFALL G2PROPOSEDBRIDGEBOXELDER CREEKNATURAL HABITATBUFFER ZONEf3c2OUTLET K2STORM DRAIN LINE KSEE SHEET ST2c1TRACT HOPEN SPACEDETRACT IFUTURE DEVELOPMENTTRACT JFUTURE DEVELOPMENTTRACT EOPEN SPACEU&DEPOND DTRACT AOPEN SPACEDEKEYMAP/ / / / / / / // / / / / / / // / / / / / / /PROSPECT RDINTERSTATE - 25 DR1DRAINAGE EXHIBIT84CALL 2 BUSINESS DAYS IN ADVANCE BEFORE YOUDIG, GRADE, OR EXCAVATE FOR THE MARKING OFUNDERGROUND MEMBER UTILITIES.CALL UTILITY NOTIFICATION CENTER OFCOLORADOKnow what'sbelow.before you dig.CallRLEGEND:PROPOSED STORM SEWERPROPOSED CURB & GUTTER PROPERTY BOUNDARYPROPOSED STORM INLETEXISTING CURB & GUTTER PROPOSED OVERLAND FLOWEXISTING MAJOR CONTOURPROPOSED MAJOR CONTOURRUNOFF SUMMARY:A2a3DRAINAGE BASIN IDEXISTING STORM SEWERPROPOSED DIRECT FLOWBASIN DELINEATION 1. REFER TO "DRAINAGE REPORT FOR GATEWAY AT PROSPECT DATED" PREPARED BYNORTHERN ENGINEERING ON 08/24/2022 FOR ADDITIONAL INFORMATION.2. REFER TO FLOODPLAIN EXHIBIT ON SHEET FLD1 FOR MORE INFORMATION ON THEFLOODPLAIN.NOTES:( IN FEET )01 INCH = 200 FEET200200400600DR1SheetGATEWAY AT PROSPECT These drawings are instruments of service provided by Northern Engineering Services, Inc. and are not to be used for any type of construction unless signed and sealed by a Professional Engineer in the employ of Northern Engineering Services, Inc.NOT FOR CO N S T R U C T I O N REVIEW SE T of 127DRAINAGEBASIN AREAPond SummariesPond IDInterim Storage(ac-ft)Interim WQCV +EURV (ac-ft)Interim ReleaseRate (cfs)Final Storage(ac-ft)*WQCCV + EURV(ac-ft)Final ReleaseRate (cfs)Pond B1.6580.12597.66.5952.96594.0Pond CN/AN/AN/A3.0901.67225.1Pond DN/AN/AN/A0.3050.1225.7Pond EN/AN/AN/A1.0980.54413.9Pond FN/AN/AN/A1.0500.55110.9Pond GN/AN/AN/A0.6780.3557.6Pond H0.8190.16321.32.8441.53922.2DETENTION SUMMARY:Rational Flow Summary |Future Developed Basin Flow RatesBASINTOTALAREA(acres)Tc2(min)Tc100(min)C2C100Q2(cfs)Q100(cfs)A129.5713.813.80.200.2511.5350.39B167.018.88.80.540.6877.47337.06C120.785.05.00.851.0048.74200.08C20.495.05.00.811.001.144.91D12.1110.910.90.200.250.924.00D21.575.05.00.851.003.8115.63E15.615.05.00.831.0213.3257.11E23.357.47.40.580.724.5119.31F16.786.36.30.650.8110.1344.21F20.445.05.00.851.001.064.34F30.645.05.00.811.001.486.35G15.075.05.00.780.9211.3346.63H117.955.05.00.851.0042.10172.83H21.635.05.00.851.003.9616.23BOX15.748.28.20.200.252.7011.78BOX24.668.28.20.200.252.199.56PUD13.138.18.10.200.251.506.55Combined BasinsBasin C (C1 and C2)21.2712.111.10.851.0037.02152.29Basin D (D1 and D2)3.6812.90.00.480.573.5414.78Basin E (E1 and E2)8.9711.90.00.750.9214.0059.95Basin F (F1, F2, and F3)7.8511.30.00.690.8511.4649.64Basin H (H1 and H2)19.5811.10.00.851.0035.61145.96Rational Flow Summary | Interim Basin Flow RatesBASINTOTALAREA(acres)Tc2(min)Tc100(min)C2C100Q2(cfs)Q100(cfs)A129.5713.813.80.200.2511.5350.39B167.0112.812.80.210.2627.79121.12C120.7812.812.80.200.258.3736.57C20.495.05.00.811.001.144.91D12.1110.910.90.200.250.924.00D21.575.35.00.851.003.8115.63E15.6112.812.80.200.252.269.88E23.359.17.40.580.724.9421.16F16.7812.812.80.200.252.7311.93F20.445.05.00.851.001.064.34F30.645.05.00.811.001.486.35G15.076.36.00.240.303.3714.50H117.9512.812.80.210.277.7233.55H21.635.05.00.851.003.9616.23BOX15.748.58.20.200.252.7612.03BOX24.668.58.20.200.252.249.76PUD13.138.38.10.200.251.506.55Combined BasinsBasin C (C1 and C2)21.2712.411.30.210.279.3440.72Basin D (D1 and D2)3.6812.90.00.480.573.5414.78Basin E (E1 and E2)8.9711.90.00.350.436.5828.34Basin F (F1, F2, and F3)7.8511.30.00.300.374.9721.36Basin H (H1 and H2)19.5811.30.00.270.3311.2848.16 Appendix B Reference Material Hydrologic Soil Group—Larimer County Area, Colorado Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 5/15/2023 Page 1 of 44490600449063044906604490690449072044907504490780449081044908404490870449090044906004490630449066044906904490720449075044907804490810449084044908704490900499480499510499540499570499600499630499660499690 499480 499510 499540 499570 499600 499630 499660 499690 40° 34' 8'' N 105° 0' 22'' W40° 34' 8'' N105° 0' 12'' W40° 33' 58'' N 105° 0' 22'' W40° 33' 58'' N 105° 0' 12'' WN 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: 1:1,490 if printed on A portrait (8.5" x 11") sheet. Soil Map may not be valid at this scale. 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 17, Sep 7, 2022 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 Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 5/15/2023 Page 2 of 4 Hydrologic Soil Group Map unit symbol Map unit name Rating Acres in AOI Percent of AOI 73 Nunn clay loam, 0 to 1 percent slopes C 2.7 28.1% 76 Nunn clay loam, wet, 1 to 3 percent slopes C 6.8 71.9% Totals for Area of Interest 9.5 100.0% Description Hydrologic soil groups are based on estimates of runoff potential. Soils are assigned to one of four groups according to the rate of water infiltration when the soils are not protected by vegetation, are thoroughly wet, and receive precipitation from long-duration storms. The soils in the United States are assigned to four groups (A, B, C, and D) and three dual classes (A/D, B/D, and C/D). The groups are defined as follows: Group A. Soils having a high infiltration rate (low runoff potential) when thoroughly wet. These consist mainly of deep, well drained to excessively drained sands or gravelly sands. These soils have a high rate of water transmission. Group B. Soils having a moderate infiltration rate when thoroughly wet. These consist chiefly of moderately deep or deep, moderately well drained or well drained soils that have moderately fine texture to moderately coarse texture. These soils have a moderate rate of water transmission. Group C. Soils having a slow infiltration rate when thoroughly wet. These consist chiefly of soils having a layer that impedes the downward movement of water or soils of moderately fine texture or fine texture. These soils have a slow rate of water transmission. Group D. Soils having a very slow infiltration rate (high runoff potential) when thoroughly wet. These consist chiefly of clays that have a high shrink-swell potential, soils that have a high water table, soils that have a claypan or clay layer at or near the surface, and soils that are shallow over nearly impervious material. These soils have a very slow rate of water transmission. If a soil is assigned to a dual hydrologic group (A/D, B/D, or C/D), the first letter is for drained areas and the second is for undrained areas. Only the soils that in their natural condition are in group D are assigned to dual classes. Rating Options Aggregation Method: Dominant Condition Hydrologic Soil Group—Larimer County Area, Colorado Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 5/15/2023 Page 3 of 4 Component Percent Cutoff: None Specified Tie-break Rule: Higher Hydrologic Soil Group—Larimer County Area, Colorado Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 5/15/2023 Page 4 of 4 PANEL LOCATOR NATIONAL FLOOD INSURANCE PROGRAMFLOOD INSURANCE RATE MAP LARIMER COUNTY, COLORADO Panel Contains: COMMUNITY NUMBER PANEL SUFFIX VERSION NUMBER MAP NUMBER EFFECTIVE DATE 1.1.1.0 08069C0984H MAY 2, 2012 NOTES TO USERS FEMANational Flood Insurance ProgramFEMA LARIMER COUNTYFORT COLLINS, CITY OF County Name SCALE Map Projection:Universal Transverse MercatorNAD 1983 UTM Zone 13NWestern Hemisphere; Vertical Datum: NAVD 88 FLOOD HAZARD INFORMATION 080101080102 09840984 HH)))))))))))) Larimer CountyUnincorporated Areas080101 Larimer CountyUnincorporated Areas080101 Larimer CountyUnincorporated Areas080101 Larimer CountyUnincorporated Areas080101 City of Fort Collins080102 City of Fort Collins080102 City of Fort Collins080102 City of Fort Collins080102 22 8 9 20 16 17 10 15 21COUNTRYSIDE DRGREENBRIARANNABEL AVE Larimer CountyUnincorporated Areas080101 D A R R E N D R I V E Sherry DriveOverflow INTERSTATE25FR O N T A G E R O AD FRONTAGE ROAD NFRONTAGE ROAD S COUNTRYSIDE DELOZIER DR KENWOOD DR MARCH CTJOHN DEERE DRIVEJAY DR JENNIE DR TANA DR TRACEY PKWY HARVESTER CT EAST PROSPECT ROAD COLLINS AIRE LN INTERNATIONAL BOULEVARD DONELLA CT ANDREASTJOANNE STSURREY LANE GREENFIELDS CTSUMMIT CT DELOZIER DRS UMM I T V I EW D R I V E SUNRISE AVEVERDE AVEGREENBRIAR DRCENTRO WAYHORIZON AVENUECLIFFORD AVENUEHARVESTER STREETTIMBERLINEROAD LINCOLN AVE RENE DRIVEBOX ELDER DRIVEKIMBERLY DRWEICKER DRIVE BUCKEYE ST REDMAN DRIVE STOCKTON AVE A L A N S T JOHN DEERE DR DAWN AVENUERIVERBEND DRGREENFIELDSHERRY DRCHERLY ST Larimer CountyUnincorporated Areas080101 SHARP POINT DRC A N A L D R SMITHFIELD DRPLEASANT ACRES LOCUST ST FRONTAGE ROAD INTERSTATE 25 FRONTAGE ROADFRONTAGEROADP L E A S A N T A C R E S D R Sherry DriveOverflow BOXELDER DRIVE S UMM I T V I EW D R I V E MULBERRY ST MULBERRY STREET DRIVERAILROADRIVERBEND CT. 40°33'45.0" 105°01'52.5"498000mE 499000mE 105°00'00" 40°33'45.0" 4491000mN 4492000mN 4493000mN 40°35'37.5" 105°00'00"3135000 FT105°01'52.5" 40°35'37.5" 1455000 FT 1450000 FT §¨¦25 RAILROAD NOTE: MAP AREA SHOWN ON THIS PANEL IS LOCATED WITHIN TOWNSHIP 7 NORTH, RANGE 68 WEST. REVISED AREA 4896.1 4923.0 4898.6 4898.1 4920.7 4898.4 4913.0 4923.1 4 9 1 3 . 6 49 0 9 . 7 4905. 2 FLOODING EFFECTS FROM CACHE LA POUDRE RIVER SPLIT R PATH 4919 . 9 4921 . 3 4916.9 494 0 . 0 4917.5 Cache LaPoudre River 4924.8 %,BG 49 3 9 . 1 4920.5 FLOODWAY CONTAINED IN CULVERT 4916.9 %,BF 4903.7STREET 4923.6 4918.9 4916.9 4945.7 Cache La PoudreRiver L Path 4930.5 4914.34942.0 4930.7 4945.6 4937.7 %,Z %,T%,S %,BH%,D%,M %,BJ %,BK %,P %,N %,O %,U %,B %,V %,Y %,A %,X%,H %,B %,C%,G %,D %,C %,M%,E%,B I %,A %,F %,G %,R %,L%,N%,C %,B %,K%,A %,K %,J%,I%,W%,I %,E %,H%,J %,F 48874890 488448924891 4886 4892 4902 4903 Bridge Boxelder DitchDiversion Dam490449054904 489349064908 4893 4901 4884 4885489949094898 48944 9 0 4 48954896489748914897 4900 48964892 4894 4895 Cache La PoudreRiver L Path Boxelder Creek Boxelder Creek Cache La PoudreRiver Lake C a n a l Cache La Poudre Reservoir Inlet BoxelderCreek CooperSlough %,B L ZONE AE SpringCreek ZONE AE ZONE AE ZONE AO (DEPTH 2) Cache La PoudreReservoir Inlet ZONE AE ZONE AE ZONE A City of Fort Collins080102 ZONE AE ZONE AE%,A ZONE AE ZONE AE Cache La Poudre RiverSplit R Path BoxelderCreek ZONE AE ZONE AE ZONE AE DRIVE %,AA ZONE AE 1%-ANNUAL-CHANCE FLOOD DISCHARGE CONTAINED IN CULVERT ZONE AE CooperSlough COURTZONE AE ZONE AE ZONE AE ZONE AE ZONE AO (DEPTH 2) ZONE AE ZONE AE ZONE AE FIELDRIDGE AVE4949.2 4930.5 4920.6 %,D 4928.3 %,E 1%-ANNUAL-CHANCE FLOOD DISCHARGE CONTAINED IN CULVERT 4902. 3%,F %,E 4900.9 1%-ANNUAL-CHANCE FLOOD DISCHARGE CONTAINED IN CULVERT Bridge 4900.5%,Q4897.1%,D 4895. 7%,C 4892.9%,BBridge Cooper SloughOverflow Culvert Culvert Culvert PANEL OF 1420 9840250500125 Meters 0 1,000 2,000500 Feet 1 inch = 500 feet 1:6,000 1001 1011 0981 0982 0992 0983 10030984 LarimerCounty *PANEL NOT PRINTED SPECIAL FLOODHAZARD AREAS OTHER AREAS OFFLOOD HAZARD OTHERAREAS GENERALSTRUCTURES Without Base Flood Elevation (BFE) With BFE or Depth Regulatory Floodway Area of Undetermined Flood Hazard Area of Minimal Flood Hazard Zone A,V, A99 Zone AE, AO, AH, VE, AR Zone X Zone D HTTP://MSC.FEMA.GOV THE INFORMATION DEPICTED ON THIS MAP AND SUPPORTINGDOCUMENTATION ARE ALSO AVAILABLE IN DIGITAL FORMAT AT SEE FIS REPORT FOR DETAILED LEGEND AND INDEX MAP FOR FIRM PANEL LAYOUT Cross Sections with 1% Annual ChanceWater Surface Elevation Coastal Transect OTHERFEATURES Profile BaselineHydrographic FeatureBase Flood Elevation Line (BFE)Limit of StudyJurisdiction Boundary Coastal Transect Baseline 17.5 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 mileFuture Conditions 1% Annual Chance Flood HazardArea with Reduced Flood Risk due to LeveeSee Notes. Zone X Zone X Zone X !(8 %,E 18.2 NO SCREEN Levee, Dike, or Floodwall Channel, Culvert, or Storm Sewer Area with Flood Risk due to Levee Zone D This map includes approximate boundaries of the CBRS for informational purposes only. Flood insurance is not available within CBRS areas for structures that are newly built or substantially improved on or after the date(s) indicated on the map. For more information see http://www.fws.gov/cbra, the FIS Report, or call the U.S. Fish and Wildlife Service Customer Service Center at 1-800-344-WILD. CBRS Area Otherwise Protected Area For information and questions about this Flood Insurance Rate Map (FIRM), available products associated with this FIRM, including historic versions, the current map date for each FIRM panel, how to order products, or the National Flood Insurance Program (NFIP) in general, please call the FEMA Map Information eXchange at 1-877-FEMA-MAP (1-877-336-2627) or visit the FEMA Flood Map Service Center website at http://msc.fema.gov. Available products may include previously issued Letters of Map Change, a Flood Insurance Study Report, and/or digital versions of this map. Many of these products can be ordered or obtained directly from the website. Communities annexing land on adjacent FIRM panels must obtain a current copy of the adjacent panel as well as the current FIRM Index. These may be ordered directly from the Flood Map Service Center at the number listed above. For community and countywide map dates refer to the Flood Insurance Study Report for this jurisdiction. To determine if flood insurance is available in this community, contact your Insurance agent or call the National Flood Insurance Program at 1-800-638-6620. Base map information shown on this FIRM was derived from U.S. Census Bureau TIGER files, dated 2010, and digital data provided by Flood County Geospatial Coordinator, dated 2010. Local vertical monuments were used to create this map. To obtain current monument information, please contact the [community contact information, phone number] or visit the website at [website address]. ACCREDITED LEVEE: Check with your local community to obtain more information, such as the estimated level of protection provided (which may exceed the 1-percent-annual-chance level) and Emergency Action Plan, on the levee system(s) shown as providing protection for areas on this panel. To mitigate flood risk in residual risk areas, property owners and residents are encouraged to consider flood insurance and floodproofing or other protective measures. For more information on flood insurance, interested parties should visit http://www.fema.gov/national-flood-insurance-program. PROVISIONALLY ACCREDITED LEVEE: Check with your local community to obtain more information, such as the estimated level of protection provided (which may exceed the 1-percent- annual-chance level) and Emergency Action Plan, on the levee system(s) shown as providing protection for areas on this panel. To maintain accreditation, the levee owner or community is required to submit the data and documentation necessary to comply with Section 65.10 of the NFIP regulations by (_____, _____). If the community or owner does not provide the necessary data and documentation or if the data and documentation provided indicate the levee system does not comply with Section 65.10 requirements, FEMA will revise the flood hazard and risk information for this area to reflect de-accreditation of the levee system. To mitigate flood risk in residual risk areas, property owners and residents are encouraged to consider flood insurance and floodproofing or other protective measures. For more information on flood insurance, interested parties should visit http://www.fema.gov/national-flood-insurance-program. LIMIT OF MODERATE WAVE ACTION: Zone AE has been divided by a Limit of Moderate Wave Action (LiMWA). The LiMWA represents the approximate landward limit of the 1.5-foot breaking wave. The effects of wave hazards between the Zone VE and the LiMWA (or between the shoreline and the LiMWA for areas where Zone VE is not identified) will be similar to, but less severe than, those in the Zone VE. and Incorporated Areas COASTAL BARRIER RESOURCES SYSTEM (CBRS) Limit of Moderate Wave Action (LiMWA)# # REVISED TO REFLECT LOMR EFFECTIVE: February 21, 2019 FINAL DRAINAGE REPORT GATEWAY TO PROSPECT FORT COLLINS, COLORADO AUGUST 24, 2022 NORTHERNENGINEERING.COM 970.221.4158 FORT COLLINS GREELEY This Drainage Report is consciously provided as a PDF. Please consider the environment before printing this document in its entirety. When a hard copy is necessary, we recommend double-sided printing. Gateway at ProspectCHARACTER OF SURFACE1: Percentage Impervious2-yr Runoff Coefficient5-yr Runoff Coefficient10-yr Runoff Coefficient100-yr Runoff CoefficientDevelopedROW (Collector 66' ROW).…………………………..……………………………………………….…………………………..……………………………………………….…………………………..……………………………………………….…………………………..………………………………………………81%0.810.810.811.00ROW (Collector 76' ROW).…………………………..……………………………………………….…………………………..……………………………………………….…………………………..……………………………………………….…………………………..………………………………………………86%0.850.850.851.00ROW (Collector 92' ROW).…………………………..……………………………………………….…………………………..……………………………………………….…………………………..……………………………………………….…………………………..………………………………………………86%0.850.850.851.00Urban Estate.…………………………..……………………………………………….…………………………..……………………………………………….…………………………..……………………………………………….…………………………..………………………………………………30%0.300.300.300.38Low Density Residential.…………………………..……………………………………………….…………………………..……………………………………………….…………………………..……………………………………………….…………………………..………………………………………………50%0.550.550.550.69Medium Density Residential.…………………………..……………………………………………….…………………………..……………………………………………….…………………………..……………………………………………….…………………………..………………………………………………70%0.650.650.650.81Commercial .…………………………..……………………………………………….…………………………..……………………………………………….…………………………..……………………………………………….…………………………..………………………………………………80%0.850.850.851.00Park.…………………………..……………………………………………….…………………………..……………………………………………….…………………………..……………………………………………….…………………………..………………………………………………25%0.350.350.350.44Unimproved AreasUndeveloped, Greenbelts, agricultural.…………………………..……………………………………………….…………………………..……………………………………………….…………………………..……………………………………………….…………………………..………………………………………………2%0.200.200.200.25Lawns Sandy Soil.…………………………..……………………………………………….…………………………..……………………………………………….…………………………..……………………………………………….…………………………..……………………………………………….…………………………..……………………………………………….…………………………..………………………………………………2%0.200.200.200.25Notes:Basin IDBasin Area(ac)Area of Collector 66' R.O.W(ac)Area of Collector 76' R.O.W (ac)Area ofCollector 92' R.O.W(ac)Area ofUrban Estate(ac)Area ofLow Density Residential(ac)Area ofMedium Density Residential(ac)Area ofCommercial(ac)Area ofPark(ac)Area of Undeveloped, Greenbelts, Agricultural(ac)Composite% Imperv.2-yearComposite RunoffCoefficient5-yearComposite RunoffCoefficient10-yearComposite RunoffCoefficient100-yearComposite Runoff CoefficientA129.57 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 29.57 2% 0.20 0.20 0.20 0.25B167.01 0.00 0.60 0.00 0.00 0.00 0.00 0.00 0.00 66.41 3% 0.21 0.21 0.21 0.26C120.78 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 20.78 2% 0.20 0.20 0.20 0.25C20.49 0.49 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 86% 0.81 0.810.81 1.00D12.11 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 2.11 2% 0.20 0.20 0.20 0.25D21.57 0.00 0.00 1.57 0.00 0.00 0.00 0.00 0.00 0.00 81% 0.85 0.850.85 1.00E15.61 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 5.61 2% 0.20 0.20 0.20 0.25E23.35 1.77 0.32 0.00 0.00 0.00 0.00 0.00 0.00 1.27 54% 0.58 0.580.58 0.72F16.78 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 6.78 2% 0.20 0.20 0.20 0.25F20.44 0.00 0.44 0.00 0.00 0.00 0.00 0.00 0.00 0.00 86% 0.85 0.850.85 1.00F30.64 0.64 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 86% 0.81 0.810.81 1.00G15.07 0.00 0.32 0.00 0.00 0.00 0.00 0.00 0.00 4.75 7% 0.24 0.24 0.24 0.30H117.95 0.00 0.37 0.00 0.00 0.00 0.00 0.00 0.00 17.58 4% 0.21 0.21 0.21 0.27H21.63 0.00 0.00 1.63 0.00 0.00 0.00 0.00 0.00 0.00 81% 0.85 0.850.85 1.00BOX1 5.74 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 5.74 2% 0.20 0.20 0.20 0.25BOX2 4.66 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 4.66 2% 0.20 0.20 0.20 0.25PUD1 3.13 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3.13 2% 0.20 0.20 0.20 0.25Basin C (C1 and C2)21.270.490.000.000.000.000.000.000.0020.784%0.210.210.210.27Basin D (D1 and D2)3.680.000.001.570.000.000.000.000.002.1136%0.480.480.480.57Basin E (E1 and E2)8.971.770.320.000.000.000.000.000.007.2022%0.350.350.350.43Basin F (F1, F2, and F3)7.850.640.440.000.000.000.000.000.007.2114%0.300.300.300.37Basin H (H1 and H2)19.580.000.371.630.000.000.000.000.0017.9510% 0.27 0.27 0.27 0.33INTERIM BASIN % IMPERVIOUSNESS AND RUNOFF COEFFICIENT CALCULATIONS2) Runoff Coefficients are taken from the Fort Collins Stormwater Criteria Manual, Chapter 3. Table 3.2-1 and 3.2-21) Percentage impervious taken from the Fort Collins Stormwater Criteria Manual, Chapter 5, Table 4.1-2 and Table 4.1-3Combined Basins Gateway at ProspectOverland Flow, Time of Concentration:Channelized Flow, Time of Concentration:Total Time of Concentration :Tc is the lesser of the values of Tc calculated using Tc = Ti + TtC2C100Length,L(ft)Slope,S(%)Ti2Ti100Length,L(ft)Slope,S(%)Roughness Coefficient Assumed Hydraulic RadiusVelocity,V(ft/s)Tt(min)Tc (Eq. 3.3-5) Tc2 = Ti +TtTc100 = Ti +TtTc2Tc100A10.200.254890.40%50.647.82002.00%0.0250.555.660.613.851.248.313.813.8Interim Pond BB10.210.265000.60%44.341.80N/AN/AN/AN/AN/A12.844.341.812.812.8C10.200.255000.50%47.444.80N/AN/AN/AN/AN/A12.847.444.812.812.8c2C20.811.00202.25%1.80.64101.00%0.0130.153.242.112.43.92.85.05.0D10.200.251101.60%15.114.3500.50%0.0250.552.830.310.915.414.510.910.9d2D20.851.00252.24%1.80.74900.50%0.0130.152.293.612.95.34.35.35.0E10.200.255000.70%42.440.00N/AN/AN/AN/AN/A12.842.440.012.812.8e2E20.580.721053.33%6.64.95001.10%0.0130.153.392.513.49.17.49.17.4F10.200.255000.60%44.642.10N/AN/AN/AN/AN/A12.844.642.112.812.8f2 F20.851.00252.24%1.80.73350.60%0.0130.152.502.212.04.02.95.05.0f3F30.811.00202.25%1.80.64101.00%0.0130.153.242.112.43.92.85.05.0Interim Pond GG10.240.30253.00%5.65.21501.00%0.0130.153.240.811.06.36.06.36.0H10.210.275000.70%41.839.30N/AN/AN/AN/AN/A12.841.839.312.812.8h2H20.851.00352.25%2.10.83752.00%0.0130.154.581.412.33.52.25.05.0BOX10.200.25152.67%4.74.45000.30%0.0250.552.193.812.98.58.28.58.2BOX20.200.25152.67%4.74.45000.30%0.0250.552.193.812.98.58.28.58.2PUD10.200.25 10 3.00% 3.7 3.5 500 0.20% 0.025 0.55 1.79 4.7 12.8 8.3 8.18.3 8.1Pond CBasin C (C1 and C2)0.210.27202.25%5.75.34101.00%1.30%15.00%0.3221.112.426.826.412.412.4Pond DBasin D (D1 and D2)0.480.57252.24%4.43.84900.50%1.30%15.00%0.2335.712.940.139.512.912.9Interim Pond EBasin E (E1 and E2)0.350.431502.00%13.612.12001.00%1.30%15.00%0.3210.311.923.922.411.911.9Pond FBasin F (F1, F2, and F3)0.300.37252.24%5.75.22001.00%1.30%15.00%0.3210.311.316.015.511.311.3Interim Pond H Basin H (H1 and H2) 0.27 0.33 35 2.26% 7.06.5 200 1.00% 1.30% 15.00% 0.32 10.3 11.3 17.3 16.8 11.3 11.3Combined BasinsINTERIM DEVELOPED DIRECT TIME OF CONCENTRATION Channelized FlowDesignPointBasinOverland FlowTime of Concentration(Equation 3.3-2 FCSCM)(Equation 5-5 FCSCM)(Equation 5-4 FCSCM)(Equation 3.3-5 FCSCM) Gateway at ProspectRational Method Equation:Rainfall Intensity:A1 29.57 13.8 13.8 0.20 0.25 1.95 6.82 11.53 50.39Interim Pond BB1 67.01 12.8 12.8 0.21 0.26 2.02 7.04 27.79 121.12C1 20.78 12.8 12.8 0.20 0.25 2.02 7.04 8.37 36.57c2C2 0.49 5.0 5.0 0.81 1.00 2.85 9.95 1.14 4.91D12.1110.910.90.200.252.177.570.924.00d2D2 1.57 5.0 5.0 0.85 1.00 2.85 9.95 3.81 15.63E1 5.61 12.8 12.8 0.20 0.25 2.02 7.04 2.26 9.88e2E2 3.35 7.4 7.4 0.58 0.72 2.52 8.80 4.94 21.16F1 6.78 12.8 12.8 0.20 0.25 2.02 7.04 2.73 11.93f2 F2 0.44 5.0 5.0 0.85 1.00 2.85 9.95 1.06 4.34f3F3 0.64 5.0 5.0 0.81 1.00 2.85 9.95 1.48 6.35Interim Pond GG1 5.07 6.0 6.0 0.24 0.30 2.76 9.63 3.37 14.50H1 17.95 12.8 12.8 0.21 0.27 2.02 7.04 7.72 33.55h2H2 1.63 5.0 5.0 0.85 1.00 2.85 9.95 3.96 16.23BOX1 5.74 8.2 8.2 0.20 0.25 2.40 8.38 2.76 12.03BOX2 4.66 8.2 8.2 0.20 0.25 2.40 8.38 2.24 9.76PUD13.138.18.10.200.252.408.381.506.55Pond CBasin C (C1 and C2)21.2712.412.40.210.272.057.169.3440.72Pond DBasin D (D1 and D2)3.6812.912.90.480.572.027.043.5414.78Interim Pond EBasin E (E1 and E2)8.9711.911.90.350.432.097.296.5828.34Pond FBasin F (F1, F2, and F3)7.8511.311.30.300.372.137.424.9721.36Interim Pond H Basin H (H1 and H2) 19.58 11.3 11.3 0.27 0.33 2.13 7.42 11.28 48.16INTERIM DEVELOPED RUNOFF COMPUTATIONSDesignPointBasin(s)Area, A(acres)Tc2(min)Flow,Q2(cfs)Flow,Q100(cfs)C2C100IDF Table for Rational Method - Table 3.4-1 FCSCMCombined BasinsTc100(min)Intensity,i2(in/hr)Intensity, i100(in/hr)()()()AiCCQf= Gateway at Prospect CHARACTER OF SURFACE1: Percentage Impervious 2-yr Runoff Coefficient 100-yr Runoff Coefficient Developed ROW (Collector 66' ROW).…………………………..……………………………………………….…………………………..……………………………………………….…………………………..……………………………………………….…………………………..………………………………………………81%0.81 1.00 ROW (Collector 76' ROW).…………………………..……………………………………………….…………………………..……………………………………………….…………………………..……………………………………………….…………………………..………………………………………………86%0.85 1.00 ROW (Collector 92' ROW).…………………………..……………………………………………….…………………………..……………………………………………….…………………………..……………………………………………….…………………………..………………………………………………86%0.85 1.00 Urban Estate .…………………………..……………………………………………….…………………………..……………………………………………….…………………………..……………………………………………….…………………………..………………………………………………30%0.30 0.38 Low Density Residential .…………………………..……………………………………………….…………………………..……………………………………………….…………………………..……………………………………………….…………………………..………………………………………………50%0.55 0.69 Medium Density Residential .…………………………..……………………………………………….…………………………..……………………………………………….…………………………..……………………………………………….…………………………..………………………………………………70%0.65 0.81 Commercial .…………………………..……………………………………………….…………………………..……………………………………………….…………………………..……………………………………………….…………………………..………………………………………………80%0.85 1.00 Park .…………………………..……………………………………………….…………………………..……………………………………………….…………………………..……………………………………………….…………………………..………………………………………………25%0.35 0.44 Unimproved Areas Undeveloped, Greenbelts, agricultural .…………………………..……………………………………………….…………………………..……………………………………………….…………………………..……………………………………………….…………………………..………………………………………………2%0.20 0.25 Lawns Sandy Soil .…………………………..……………………………………………….…………………………..……………………………………………….…………………………..……………………………………………….…………………………..……………………………………………….…………………………..……………………………………………….…………………………..………………………………………………2%0.20 0.25 Notes: Basin ID Basin Area (ac) Area of Collector 66' R.O.W (ac) Area of Collector 76' R.O.W (ac) Area of Collector 92' R.O.W (ac) Area of Urban Estate (ac) Area of Low Density Residential (ac) Area of Medium Density Residential (ac) Area of Commercia l (ac) Area of Park (ac) Area of Undeveloped, Greenbelts, Agricultural (ac) Composite % Imperv. 2-year Composite Runoff Coefficient 100-year Composite Runoff Coefficient A1 29.57 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 29.57 2% 0.20 0.25 B1 67.01 0.00 0.60 0.00 13.56 52.88 0.00 0.00 0.00 13.53 47% 0.54 0.68 C1 20.78 0.00 0.00 0.00 0.00 0.00 0.00 20.78 0.00 0.00 80% 0.85 1.00 C2 0.49 0.49 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 86% 0.81 1.00 D1 2.11 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 2.11 2% 0.20 0.25 D2 1.57 0.00 0.00 1.57 0.00 0.00 0.00 0.00 0.00 0.00 81% 0.85 1.00 E1 5.61 0.00 0.00 0.00 0.00 0.00 5.61 0.00 0.00 0.00 70% 0.65 0.81 E2 3.35 1.77 0.32 0.00 0.00 0.00 0.00 0.00 0.00 1.27 54% 0.58 0.72 F1 6.78 0.00 0.00 0.00 0.00 0.00 6.78 0.00 0.00 0.00 70% 0.65 0.81 F2 0.44 0.00 0.44 0.00 0.00 0.00 0.00 0.00 0.00 0.00 86% 0.85 1.00 F3 0.64 0.64 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 86% 0.81 1.00 G1 5.07 0.00 0.32 0.00 0.00 0.00 0.00 4.20 0.00 0.67 72% 0.78 0.92 H1 17.95 0.00 0.37 0.00 0.00 0.00 0.00 17.58 0.00 0.00 80% 0.85 1.00 H2 1.63 0.00 0.00 1.63 0.00 0.00 0.00 0.00 0.00 0.00 81% 0.85 1.00 BOX1 5.74 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 5.74 2% 0.20 0.25 BOX2 4.66 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 4.66 2% 0.20 0.25 PUD1 3.13 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3.13 2% 0.20 0.25 Basin C (C1 and C2)21.27 0.49 0.00 0.00 0.00 0.00 0.00 20.78 0.00 0.00 80%0.85 1.00 Basin D (D1 and D2)3.68 0.00 0.00 1.57 0.00 0.00 0.00 0.00 0.00 2.11 36%0.48 0.57 Basin E (E1 and E2)8.97 1.77 0.32 0.00 0.00 0.00 5.61 0.00 0.00 1.58 64%0.63 0.79 Basin F (F1, F2, and F3)7.85 0.64 0.44 0.00 0.00 0.00 6.78 0.00 0.00 0.44 72%0.69 0.85 Basin H (H1 and H2)19.58 0.00 0.37 1.63 0.00 0.00 0.00 17.58 0.00 0.37 80% 0.85 1.00 FUTURE BASIN % IMPERVIOUSNESS AND RUNOFF COEFFICIENT CALCULATIONS 2) Runoff Coefficients are taken from the Fort Collins Stormwater Criteria Manual, Chapter 3. Table 3.2-1 and 3.2-2 1) Percentage impervious taken from the Fort Collins Stormwater Criteria Manual, Chapter 5, Table 4.1-2 and Table 4.1-3 Combined Basins Gateway at Prospect Rational Method Equation: Rainfall Intensity: A1 29.57 13.8 13.8 0.20 0.25 1.95 6.82 11.53 50.39 Pond B B1 67.01 11.1 8.8 0.54 0.68 2.13 7.42 77.47 337.06 C1 20.78 5.5 5.0 0.85 1.00 2.76 9.63 48.74 200.08 c2 C2 0.49 5.0 5.0 0.81 1.00 2.85 9.95 1.14 4.91 D1 2.11 10.9 10.9 0.20 0.25 2.17 7.57 0.92 4.00 d2 D2 1.57 5.3 5.0 0.85 1.00 2.85 9.95 3.81 15.63 E1 5.61 5.0 5.0 0.65 0.81 2.85 9.95 10.40 45.39 e2 E2 3.35 9.1 7.4 0.58 0.72 2.30 8.03 4.51 19.31 F1 6.78 9.2 6.3 0.65 0.81 2.30 8.03 10.13 44.21 f2 F2 0.44 5.0 5.0 0.85 1.00 2.85 9.95 1.06 4.34 f3 F3 0.64 5.0 5.0 0.81 1.00 2.85 9.95 1.48 6.35 Pond G G1 5.07 5.0 5.0 0.78 0.92 2.85 9.95 11.33 46.63 H1 17.95 5.6 5.0 0.85 1.00 2.76 9.63 42.10 172.83 h2 H2 1.63 5.0 5.0 0.85 1.00 2.85 9.95 3.96 16.23 BOX1 5.74 8.5 8.2 0.20 0.25 2.35 8.21 2.70 11.78 BOX2 4.66 8.5 8.2 0.20 0.25 2.35 8.21 2.19 9.56 PUD1 3.13 8.3 8.1 0.20 0.25 2.40 8.38 1.50 6.55 Pond C Basin C (C1 and C2)21.27 12.1 12.1 0.85 1.00 2.05 7.16 37.02 152.29 Pond D Basin D (D1 and D2)3.68 12.9 12.9 0.48 0.57 2.02 7.04 3.54 14.78 Pond E Basin E (E1 and E2)8.97 11.9 11.9 0.63 0.79 2.09 7.29 11.86 51.36 Pond F Basin F (F1, F2, and F3)7.85 11.3 11.3 0.69 0.85 2.13 7.42 11.46 49.64 Pond H Basin H (H1 and H2) 19.58 11.1 11.1 0.85 1.00 2.13 7.42 35.61 145.96 Combined Basins Tc100 (min) Intensity, i2 (in/hr) Intensity, i100 (in/hr) FUTURE DEVELOPED RUNOFF COMPUTATIONS Design Point Basin(s)Area, A (acres) Tc2 (min) Flow, Q2 (cfs) Flow, Q100 (cfs) C2 C100 IDF Table for Rational Method - Table 3.4-1 FCSCM ()()()AiCCQf= Gateway at Prospect BASIN TOTAL AREA (acres) Tc2 (min) Tc100 (min) C2 C100 Q2 (cfs) Q100 (cfs) A1 29.57 13.8 13.8 0.20 0.25 11.53 50.39 B1 67.01 8.8 8.8 0.54 0.68 77.47 337.06 C1 20.78 5.0 5.0 0.85 1.00 48.74 200.08 C2 0.49 5.0 5.0 0.81 1.00 1.14 4.91 D1 2.11 10.9 10.9 0.20 0.25 0.92 4.00 D2 1.57 5.0 5.0 0.85 1.00 3.81 15.63 E1 5.61 5.0 5.0 0.65 0.81 10.40 45.39 E2 3.35 7.4 7.4 0.58 0.72 4.51 19.31 F1 6.78 6.3 6.3 0.65 0.81 10.13 44.21 F2 0.44 5.0 5.0 0.85 1.00 1.06 4.34 F3 0.64 5.0 5.0 0.81 1.00 1.48 6.35 G1 5.07 5.0 5.0 0.78 0.92 11.33 46.63 H1 17.95 5.0 5.0 0.85 1.00 42.10 172.83 H2 1.63 5.0 5.0 0.85 1.00 3.96 16.23 BOX1 5.74 8.2 8.2 0.20 0.25 2.70 11.78 BOX2 4.66 8.2 8.2 0.20 0.25 2.19 9.56 PUD1 3.13 8.1 8.1 0.20 0.25 1.50 6.55 Basin C (C1 and C2)21.27 12.1 11.1 0.85 1.00 37.02 152.29 Basin D (D1 and D2)3.68 12.9 0.0 0.48 0.57 3.54 14.78 Basin E (E1 and E2)8.97 11.9 0.0 0.63 0.79 11.86 51.36 Basin F (F1, F2, and F3)7.85 11.3 0.0 0.69 0.85 11.46 49.64 Basin H (H1 and H2) 19.58 11.1 0.0 0.85 1.00 35.61 145.96 Rational Flow Summary |Future Developed Basin Flow Rates Combined Basins 8/24/202211:49 AM P:\892-002\Drainage\Hydrology\889-002_Proposed Rational Calcs (Final Master Planning - FCSCM Overhaul)\Summary Tables PANEL LOCATOR NATIONAL FLOOD INSURANCE PROGRAMFLOOD INSURANCE RATE MAP LARIMER COUNTY, COLORADO Panel Contains: COMMUNITY NUMBER PANEL SUFFIX VERSION NUMBER MAP NUMBER EFFECTIVE DATE 1.1.1.0 08069C0984H MAY 2, 2012 NOTES TO USERS FEMANational Flood Insurance ProgramFEMA LARIMER COUNTYFORT COLLINS, CITY OF County Name SCALE Map Projection:Universal Transverse MercatorNAD 1983 UTM Zone 13NWestern Hemisphere; Vertical Datum: NAVD 88 FLOOD HAZARD INFORMATION 080101080102 09840984 HH)))))))))))) Larimer CountyUnincorporated Areas080101 Larimer CountyUnincorporated Areas080101 Larimer CountyUnincorporated Areas080101 Larimer CountyUnincorporated Areas080101 City of Fort Collins080102 City of Fort Collins080102 City of Fort Collins080102 City of Fort Collins080102 22 8 9 20 16 17 10 15 21COUNTRYSIDE DRGREENBRIARANNABEL AVE Larimer CountyUnincorporated Areas080101 D A R R E N D R I V E Sherry DriveOverflow INTERSTATE25FR O N T A G E R O AD FRONTAGE ROAD NFRONTAGE ROAD S COUNTRYSIDE DELOZIER DR KENWOOD DR MARCH CTJOHN DEERE DRIVEJAY DR JENNIE DR TANA DR TRACEY PKWY HARVESTER CT EAST PROSPECT ROAD COLLINS AIRE LN INTERNATIONAL BOULEVARD DONELLA CT ANDREASTJOANNE STSURREY LANE GREENFIELDS CTSUMMIT CT DELOZIER DRS UMM I T V I EW D R I V E SUNRISE AVEVERDE AVEGREENBRIAR DRCENTRO WAYHORIZON AVENUECLIFFORD AVENUEHARVESTER STREETTIMBERLINEROAD LINCOLN AVE RENE DRIVEBOX ELDER DRIVEKIMBERLY DRWEICKER DRIVE BUCKEYE ST REDMAN DRIVE STOCKTON AVE A L A N S T JOHN DEERE DR DAWN AVENUERIVERBEND DRGREENFIELDSHERRY DRCHERLY ST Larimer CountyUnincorporated Areas080101 SHARP POINT DRC A N A L D R SMITHFIELD DRPLEASANT ACRES LOCUST ST FRONTAGE ROAD INTERSTATE 25 FRONTAGE ROADFRONTAGEROADP L E A S A N T A C R E S D R Sherry DriveOverflow BOXELDER DRIVE S UMM I T V I EW D R I V E MULBERRY ST MULBERRY STREET DRIVERAILROADRIVERBEND CT. 40°33'45.0" 105°01'52.5"498000mE 499000mE 105°00'00" 40°33'45.0" 4491000mN 4492000mN 4493000mN 40°35'37.5" 105°00'00"3135000 FT105°01'52.5" 40°35'37.5" 1455000 FT 1450000 FT §¨¦25 RAILROAD NOTE: MAP AREA SHOWN ON THIS PANEL IS LOCATED WITHIN TOWNSHIP 7 NORTH, RANGE 68 WEST. REVISED AREA 4896.1 4923.0 4898.6 4898.1 4920.7 4898.4 4913.0 4923.1 4 9 1 3 . 6 49 0 9 . 7 4905. 2 FLOODING EFFECTS FROM CACHE LA POUDRE RIVER SPLIT R PATH 4919 . 9 4921 . 3 4916.9 494 0 . 0 4917.5 Cache LaPoudre River 4924.8 %,BG 49 3 9 . 1 4920.5 FLOODWAY CONTAINED IN CULVERT 4916.9 %,BF 4903.7STREET 4923.6 4918.9 4916.9 4945.7 Cache La PoudreRiver L Path 4930.5 4914.34942.0 4930.7 4945.6 4937.7 %,Z %,T%,S %,BH%,D%,M %,BJ %,BK %,P %,N %,O %,U %,B %,V %,Y %,A %,X%,H %,B %,C%,G %,D %,C %,M%,E%,B I %,A %,F %,G %,R %,L%,N%,C %,B %,K%,A %,K %,J%,I%,W%,I %,E %,H%,J %,F 48874890 488448924891 4886 4892 4902 4903 Bridge Boxelder DitchDiversion Dam490449054904 489349064908 4893 4901 4884 4885489949094898 48944 9 0 4 48954896489748914897 4900 48964892 4894 4895 Cache La PoudreRiver L Path Boxelder Creek Boxelder Creek Cache La PoudreRiver Lake C a n a l Cache La Poudre Reservoir Inlet BoxelderCreek CooperSlough %,B L ZONE AE SpringCreek ZONE AE ZONE AE ZONE AO (DEPTH 2) Cache La PoudreReservoir Inlet ZONE AE ZONE AE ZONE A City of Fort Collins080102 ZONE AE ZONE AE%,A ZONE AE ZONE AE Cache La Poudre RiverSplit R Path BoxelderCreek ZONE AE ZONE AE ZONE AE DRIVE %,AA ZONE AE 1%-ANNUAL-CHANCE FLOOD DISCHARGE CONTAINED IN CULVERT ZONE AE CooperSlough COURTZONE AE ZONE AE ZONE AE ZONE AE ZONE AO (DEPTH 2) ZONE AE ZONE AE ZONE AE FIELDRIDGE AVE4949.2 4930.5 4920.6 %,D 4928.3 %,E 1%-ANNUAL-CHANCE FLOOD DISCHARGE CONTAINED IN CULVERT 4902. 3%,F %,E 4900.9 1%-ANNUAL-CHANCE FLOOD DISCHARGE CONTAINED IN CULVERT Bridge 4900.5%,Q4897.1%,D 4895. 7%,C 4892.9%,BBridge Cooper SloughOverflow Culvert Culvert Culvert PANEL OF 1420 9840250500125 Meters 0 1,000 2,000500 Feet 1 inch = 500 feet 1:6,000 1001 1011 0981 0982 0992 0983 10030984 LarimerCounty *PANEL NOT PRINTED SPECIAL FLOODHAZARD AREAS OTHER AREAS OFFLOOD HAZARD OTHERAREAS GENERALSTRUCTURES Without Base Flood Elevation (BFE) With BFE or Depth Regulatory Floodway Area of Undetermined Flood Hazard Area of Minimal Flood Hazard Zone A,V, A99 Zone AE, AO, AH, VE, AR Zone X Zone D HTTP://MSC.FEMA.GOV THE INFORMATION DEPICTED ON THIS MAP AND SUPPORTINGDOCUMENTATION ARE ALSO AVAILABLE IN DIGITAL FORMAT AT SEE FIS REPORT FOR DETAILED LEGEND AND INDEX MAP FOR FIRM PANEL LAYOUT Cross Sections with 1% Annual ChanceWater Surface Elevation Coastal Transect OTHERFEATURES Profile BaselineHydrographic FeatureBase Flood Elevation Line (BFE)Limit of StudyJurisdiction Boundary Coastal Transect Baseline 17.5 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 mileFuture Conditions 1% Annual Chance Flood HazardArea with Reduced Flood Risk due to LeveeSee Notes. Zone X Zone X Zone X !(8 %,E 18.2 NO SCREEN Levee, Dike, or Floodwall Channel, Culvert, or Storm Sewer Area with Flood Risk due to Levee Zone D This map includes approximate boundaries of the CBRS for informational purposes only. Flood insurance is not available within CBRS areas for structures that are newly built or substantially improved on or after the date(s) indicated on the map. For more information see http://www.fws.gov/cbra, the FIS Report, or call the U.S. Fish and Wildlife Service Customer Service Center at 1-800-344-WILD. CBRS Area Otherwise Protected Area For information and questions about this Flood Insurance Rate Map (FIRM), available products associated with this FIRM, including historic versions, the current map date for each FIRM panel, how to order products, or the National Flood Insurance Program (NFIP) in general, please call the FEMA Map Information eXchange at 1-877-FEMA-MAP (1-877-336-2627) or visit the FEMA Flood Map Service Center website at http://msc.fema.gov. Available products may include previously issued Letters of Map Change, a Flood Insurance Study Report, and/or digital versions of this map. Many of these products can be ordered or obtained directly from the website. Communities annexing land on adjacent FIRM panels must obtain a current copy of the adjacent panel as well as the current FIRM Index. These may be ordered directly from the Flood Map Service Center at the number listed above. For community and countywide map dates refer to the Flood Insurance Study Report for this jurisdiction. To determine if flood insurance is available in this community, contact your Insurance agent or call the National Flood Insurance Program at 1-800-638-6620. Base map information shown on this FIRM was derived from U.S. Census Bureau TIGER files, dated 2010, and digital data provided by Flood County Geospatial Coordinator, dated 2010. Local vertical monuments were used to create this map. To obtain current monument information, please contact the [community contact information, phone number] or visit the website at [website address]. ACCREDITED LEVEE: Check with your local community to obtain more information, such as the estimated level of protection provided (which may exceed the 1-percent-annual-chance level) and Emergency Action Plan, on the levee system(s) shown as providing protection for areas on this panel. To mitigate flood risk in residual risk areas, property owners and residents are encouraged to consider flood insurance and floodproofing or other protective measures. For more information on flood insurance, interested parties should visit http://www.fema.gov/national-flood-insurance-program. PROVISIONALLY ACCREDITED LEVEE: Check with your local community to obtain more information, such as the estimated level of protection provided (which may exceed the 1-percent- annual-chance level) and Emergency Action Plan, on the levee system(s) shown as providing protection for areas on this panel. To maintain accreditation, the levee owner or community is required to submit the data and documentation necessary to comply with Section 65.10 of the NFIP regulations by (_____, _____). If the community or owner does not provide the necessary data and documentation or if the data and documentation provided indicate the levee system does not comply with Section 65.10 requirements, FEMA will revise the flood hazard and risk information for this area to reflect de-accreditation of the levee system. To mitigate flood risk in residual risk areas, property owners and residents are encouraged to consider flood insurance and floodproofing or other protective measures. For more information on flood insurance, interested parties should visit http://www.fema.gov/national-flood-insurance-program. LIMIT OF MODERATE WAVE ACTION: Zone AE has been divided by a Limit of Moderate Wave Action (LiMWA). The LiMWA represents the approximate landward limit of the 1.5-foot breaking wave. The effects of wave hazards between the Zone VE and the LiMWA (or between the shoreline and the LiMWA for areas where Zone VE is not identified) will be similar to, but less severe than, those in the Zone VE. and Incorporated Areas COASTAL BARRIER RESOURCES SYSTEM (CBRS) Limit of Moderate Wave Action (LiMWA)# # REVISED TO REFLECT LOMR EFFECTIVE: February 21, 2019 XXXXX / / / / / / / /FO/ / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / /X10" SS/ / / / / / / / FO FO FO FO T S VAULTELECT VAULTELEC T S V.P. GASTESTSTA VAULTELEC T S TESTSTA MH / / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / /GAS GAS GAS F.O. F.O. F.O. ELEC ELEC ELEC ELEC ELECELECELECELEC ELEC ELEC VAULTELEC VAULTELEC VAULTELEC VAULTELEC AC T ELEC VAULTELECVAULTELECTRAFFICVAULTE VAULTELECTRAFFICVAULT ELEC T S T S T ST S VAULTELEC ELEC VAULTELEC VAULTELEC E BASIN B - ZONE LMN AND UE RESPONSIBLE FOR 67.48 ACRES OF LID REQUIREMENTS PER CITY OF FORT COLLINS STANDARDS BASIN C - ZONE LMN AND UE RESPONSIBLE FOR 21.27 ACRES OF LID REQUIREMENTS PER CITY OF FORT COLLINS STANDARDS BASIN F - ZONE MMN RESPONSIBLE FOR 7.85 ACRES OF LID REQUIREMENTS PER CITY OF FORT COLLINS STANDARDS BASIN D - ZONE GREENBELT AND OPEN SPACE RESPONSIBLE FOR 0 ACRES OF LID REQUIREMENTS PER CITY OF FORT COLLINS STANDARDS AS LONG AS IT REMAINS UNDEVELOPED. BASIN G - ZONE CE RESPONSIBLE FOR 5.87 ACRES OF LID REQUIREMENTS PER CITY OF FORT COLLINS STANDARDS (BASIN G IS RESPONSIBLE FOR HALF THE LID TREATMENT OF SUB-BASIN H2) BASIN E - ZONE MMN RESPONSIBLE FOR 8.53 ACRES OF LID REQUIREMENTS PER CITY OF FORT COLLINS STANDARDS PROSPECT ROAD BASIN A - ZONE GREENBELT AND OPEN SPACE RESPONSIBLE FOR 0 ACRES OF LID REQUIREMENTS PER CITY OF FORT COLLINS STANDARDS AS LONG AS IT REMAINS UNDEVELOPED. BASIN H - ZONE CE RESPONSIBLE FOR 20.35 ACRES OF LID REQUIREMENTS PER CITY OF FORT COLLINS STANDARDS (BASIN H IS RESPONSIBLE FOR LID TREATMENT OF SUB-BASIN D2) LID/WQCV REQUIREMENTS FOR EACH PARCEL FORT COLLINS, CO GATEWAY AT PROSPECT E N G I N E E R N GI EHTRON R N 08.19.2022 P:\892-002\DWG\DRNG\892-002_LID.DWG NOTES: 1. EACH PARCEL IS RESPONSIBLE FOR THEIR LID AND WQCV SIZING BASED ON ACREAGE SIZE DEPICTED ON THIS EXHIBIT. THIS INCLUDES PORTIONS OF ADJACENT RIGHT-OF-WAYS. 2. LID AND WQCV REQUIREMENT AREAS ARE NOT EQUAL TO DETENTION AREA REQUIREMENTS. 3. FOR ADDITIONAL INFORMATION ON THE BASIN DELINEATIONS REFER TO THE DRAINAGE PLAN FROM GATEWAY AT PROSPECT UTILITY PLAN SET. 4. LID AND WQCV SIZING MUST FOLLOW CITY OF FORT COLLINS STANDARDS. 5. AT THE TIME OF EACH PARCELS DEVELOPMENT THE DESIGN ENGINEER SHALL CALCULATE THE PROPOSED PERCENT IMPERVIOUS AND NOT USE THE IMPERVIOUS LISTED IN THE FINAL DRAINAGE REPORT FOR GATEWAY AT PROSPECT BY NORTHERN ENGINEERING. LEGEND: BASIN B BASIN C BASIN E BASIN F BASIN G BASIN H Basin ID WQCV/LID Area (ac.) A 0 B 67.48 C 21.27 D 0 E 8.53 F 7.85 G 5.87 H 20.35 SUMMARY: Appendix C Hydrologic & Hydraulic Calculations Imperviousness QT - Fort Collins Input Parameters E1 E1 0.00 0.00 2.17 2.17 2% 0.00 0.00 2.17 2.17 2% A1 A1 0.00 0.12 0.00 0.12 90% A2 A2 0.00 0.17 0.00 0.17 90% A3 A3 0.43 0.00 0.01 0.44 98% A4 A4 0.11 0.00 0.03 0.13 85% A5 A5 0.11 0.00 0.02 0.14 79% A6 A6 0.03 0.00 0.06 0.09 35% A7 A7 0.17 0.00 0.24 0.41 43% A8 A8 0.00 0.00 0.60 0.60 2% 0.25 0.12 0.11 0.48 75% 0.85 0.29 0.96 2.10 54% B1 B1 0.00 0.00 0.03 0.03 2% B2 B2 0.00 0.00 0.04 0.04 2% 0.00 0.00 0.07 0.07 2% C1 C1 0.66 0.00 0.45 1.11 60% C2 C2 0.08 0.00 0.00 0.08 100% 0.74 0.00 0.45 1.19 63% 1.59 0.29 1.48 3.36 56% 0.85 0.29 2.17 2.17 53% 1.59 0.29 2.01 3.29 57% A+B Basins (Oniste) A+C Basins (Pond) Total A Total B Total Site A BASINS B BASINS C BASINS Total C Existing Basins Developed Rain Garden A Calculated Percent Impervious (%) Landscape (i= 2) Total Exising Roof (i=90)Pavement (i=100) Total Area (Acres) Design PointBasin(s) GLF QT Fort Collins Percent Impervious.xlsx 6/6/2023 Coefficients QT - Fort Collins 2-YR Return 10-YR Return 100-YR Return Length (ft) Slope (%) Ti2 Ti100 Velocity (ft/s) Length (ft) Tt E1 E1 0.00 0.00 2.17 0.00 0.00 2.17 0.20 0.20 0.20 0.25 416.00 0.90 35.6 33.6 0.1 0 0.0 0.00 0.00 2.17 0.00 0.00 2.17 0.20 0.20 0.20 0.25 416.00 0.90 35.6 33.6 0.1 0 0.0 A1 A1 0.00 0.12 0.00 0.00 0.00 0.12 0.95 0.95 0.95 1.00 45.00 0.50 2.4 1.6 0.02 0 0.0 A2 A2 0.00 0.17 0.00 0.00 0.00 0.17 0.95 0.95 0.95 1.00 25.00 0.50 1.8 1.2 0.06 0 0.0 A3 A3 0.43 0.00 0.01 0.00 0.00 0.44 0.93 0.93 0.93 1.00 190.00 1.80 3.5 2.1 2 10 0.1 A4 A4 0.11 0.00 0.00 0.00 0.02 0.13 0.86 0.86 0.86 1.00 100.00 2.40 3.4 1.4 0.06 0 0.0 A5 A5 0.11 0.00 0.00 0.01 0.02 0.14 0.81 0.81 0.81 1.00 103.00 2.40 4.1 1.4 0.01 0 0.0 A6 A6 0.03 0.00 0.00 0.03 0.03 0.09 0.52 0.52 0.52 0.65 20.00 1.00 4.9 3.8 3.97 145 0.6 A7 A7 0.17 0.00 0.04 0.10 0.10 0.41 0.56 0.56 0.56 0.70 12.00 2.00 2.8 2.1 2 480 4.0 A8 A8 0.00 0.00 0.22 0.10 0.28 0.60 0.28 0.28 0.28 0.35 40.00 2.00 7.7 7.1 1.06 250 3.9 0.85 0.29 0.27 0.24 0.45 2.10 0.65 0.65 0.65 0.81 20.00 2.00 3.0 1.9 2 800 6.7 B1 B1 0.00 0.00 0.00 0.00 0.03 0.03 0.35 0.35 0.35 0.44 15.00 25.00 1.9 1.6 0.03 0 0.0 B2 B2 0.00 0.00 0.00 0.00 0.04 0.04 0.35 0.35 0.35 0.44 15.00 25.00 1.9 1.6 0.03 0 0.0 0.00 0.00 0.00 0.00 0.07 0.07 0.35 0.35 0.35 0.44 50.00 5.00 5.8 5.1 0.15 0 0.0 C1 C1 0.66 0.00 0.05 0.40 0.00 1.11 0.66 0.66 0.66 0.83 95.00 2.00 6.3 3.9 2.1 650 5.2 C2 C2 0.08 0.00 0.00 0.00 0.00 0.08 0.95 0.95 0.95 1.00 12.00 2.00 0.8 0.5 1.41 300 3.5 0.74 0.00 0.05 0.40 0.00 1.19 0.68 0.68 0.68 0.85 95.00 2.00 6.0 3.6 2.1 650 5.2 1.59 0.29 0.32 0.64 0.52 3.36 0.65 0.65 0.65 0.82 95.00 2.00 6.5 4.1 2.1 650 5.2 0.85 0.29 0.54 0.48 1.04 2.17 0.77 0.77 0.77 0.96 12.00 2.00 1.7 0.7 2.14 712 5.5 1.59 0.29 0.32 0.64 0.45 3.34 0.65 0.65 0.65 0.81 95.00 2.00 6.5 4.2 2.1 650 5.2 A+B Basins (Oniste) A+C Basins+B3 (Pond) Total A Total B Total Site A BASINS B BASINS C BASINS Total C Existing Basins Developed Adjusted Coefficent Calculated Weighted Coefficient (%) Landscape (c= 20) Total Exising Landscape (c= 25) Landscape (c= 35)Roof (c=95)Pavement (c=95) Total Area (Acres) Design PointBasin(s) Channelized Flow Time (min)Overland Flow Time (min) DAS QT Fort Collins Coefficients.xlsx 6/6/2023 Coefficients QT - Fort Collins Tc (Eq. 3.3-5 Tc2 = Ti+Tt (min) Tc100 = Ti+Tt (min) Tc2 (min) Tc100 (min) 12.3 35.6 33.6 12.3 12.3 0.25 12.3 35.6 33.6 12.3 12.3 0.25 10.3 2.4 1.6 5.0 5.0 1.19 10.1 1.8 1.2 5.0 5.0 1.19 11.1 3.6 2.2 5.0 5.0 1.17 10.6 3.4 1.4 5.0 5.0 1.07 10.6 4.1 1.4 5.0 5.0 1.02 10.9 5.5 4.4 5.5 5.0 0.65 12.7 6.8 6.1 6.8 6.1 0.70 11.6 11.6 11.0 11.6 11.0 0.35 14.6 9.7 8.6 9.7 8.6 0.81 10.1 1.9 1.6 5.0 5.0 0.44 10.1 1.9 1.6 5.0 5.0 0.44 10.3 5.8 5.1 5.8 5.1 0.44 14.1 11.5 9.1 11.5 9.1 0.83 11.7 4.3 4.1 5.0 5.0 1.19 14.1 11.2 8.7 11.2 8.7 0.85 14.1 11.6 9.3 11.6 9.3 0.82 14.0 7.2 6.2 7.2 6.2 0.96 14.1 11.7 9.3 11.7 9.3 0.81 Time of Concentration DAS QT Fort Collins Coefficients.xlsx 6/6/2023 Designer: Company:2-yr 5-yr 10-yr 25-yr 50-yr 100-yr 500-yr Date:1-hour rainfall depth, P1 (in) =0.82 1.40 2.86 Project:a b c Location:Rainfall Intensity Equation Coefficients =28.50 10.00 0.786 2-yr 5-yr 10-yr 25-yr 50-yr 100-yr 500-yr Overland Flow Length Li (ft) U/S Elevation (ft) (Optional) D/S Elevation (ft) (Optional) Overland Flow Slope Si (ft/ft) Overland Flow Time ti (min) Channelized Flow Length Lt (ft) U/S Elevation (ft) (Optional) D/S Elevation (ft) (Optional) Channelized Flow Slope St (ft/ft) NRCS Conveyance Factor K Channelized Flow Velocity Vt (ft/sec) Channelized Flow Time tt (min) Computed tc (min) Regional tc (min) Selected tc (min)2-yr 5-yr 10-yr 25-yr 50-yr 100-yr 500-yr 2-yr 5-yr 10-yr 25-yr 50-yr 100-yr 500-yr 0.01 0.05 0.15 0.33 0.40 0.49 0.59 40.59 40.59 25.66 1.41 2.40 4.91 0.03 0.77 5.25 0.20 0.20 0.25 12.30 2.04 3.48 7.10 0.88 1.51 3.85 0.74 0.77 0.79 0.82 0.84 0.85 0.87 5.05 5.05 5.05 2.77 4.74 9.68 0.25 0.45 0.99 0.95 0.95 1.00 5.00 2.78 4.75 9.70 0.32 0.54 1.16 0.74 0.77 0.79 0.82 0.84 0.85 0.87 3.76 3.76 5.00 2.78 4.75 9.70 0.35 0.64 1.41 0.95 0.95 1.00 5.00 2.78 4.75 9.70 0.45 0.77 1.65 0.82 0.83 0.85 0.87 0.88 0.88 0.90 5.46 5.54 5.54 2.70 4.62 9.43 0.97 1.73 3.67 0.93 0.93 1.00 5.00 2.78 4.75 9.70 1.14 1.94 4.27 0.69 0.73 0.76 0.80 0.81 0.83 0.86 5.03 5.03 5.03 2.78 4.74 9.68 0.25 0.47 1.05 0.86 0.86 1.00 5.00 2.78 4.75 9.70 0.31 0.53 1.26 0.64 0.68 0.71 0.76 0.78 0.81 0.84 5.81 5.81 5.81 2.67 4.56 9.31 0.24 0.45 1.05 0.81 0.86 1.00 5.00 2.78 4.75 9.70 0.32 0.57 1.36 0.26 0.32 0.39 0.52 0.57 0.63 0.70 6.30 6.90 6.90 2.53 4.32 8.83 0.06 0.15 0.50 0.52 0.52 0.65 5.00 2.78 4.75 9.70 0.13 0.22 0.57 0.32 0.39 0.45 0.56 0.61 0.66 0.72 3.56 7.56 7.56 2.46 4.20 8.57 0.33 0.77 2.32 0.56 0.56 0.70 6.10 2.63 4.49 9.18 0.60 1.03 2.63 0.01 0.05 0.15 0.33 0.40 0.49 0.59 9.53 13.45 13.45 1.96 3.34 6.83 0.01 0.29 2.02 0.28 0.28 0.35 11.00 2.13 3.65 7.45 0.36 0.61 1.56 0.43 0.48 0.54 0.63 0.66 0.71 0.76 3.96 10.63 10.63 2.17 3.70 7.55 2.14 4.60 12.42 0.65 0.65 0.81 8.60 2.35 4.01 8.19 3.54 6.05 15.39 0.35 0.35 0.44 0.01 0.05 0.15 0.33 0.40 0.49 0.59 2.53 2.53 10.00 2.22 3.79 7.74 0.00 0.02 0.11 0.35 0.35 0.44 5.00 2.78 4.75 9.70 0.03 0.05 0.13 0.01 0.05 0.15 0.33 0.40 0.49 0.59 2.53 2.53 10.00 2.22 3.79 7.74 0.00 0.02 0.15 0.35 0.35 0.40 5.00 2.78 4.75 9.70 0.04 0.07 0.16 0.01 0.05 0.15 0.33 0.40 0.49 0.59 7.87 7.87 10.00 2.22 3.79 7.74 0.00 0.04 0.27 0.33 0.33 0.42 5.10 2.77 4.72 9.65 0.06 0.11 0.28 0.47 0.52 0.57 0.66 0.69 0.73 0.78 8.06 13.23 13.23 1.97 3.37 6.88 1.03 2.14 5.57 0.66 0.66 0.83 9.10 2.30 3.93 8.02 1.69 2.88 7.39 0.83 0.85 0.87 0.88 0.89 0.89 0.90 1.24 4.78 5.00 2.78 4.75 9.70 0.19 0.33 0.69 0.95 0.95 1.00 5.00 2.78 4.75 9.70 0.21 0.36 0.78 0.51 0.56 0.60 0.68 0.71 0.75 0.79 7.61 12.77 12.77 2.00 3.42 6.99 1.26 2.55 6.46 0.69 0.69 0.87 8.50 2.36 4.03 8.23 2.02 3.45 8.87 0.44 0.49 0.54 0.63 0.67 0.71 0.76 6.46 14.46 14.46 1.89 3.23 6.61 2.77 5.91 15.83 0.65 0.65 0.82 9.20 2.29 3.91 7.99 5.00 8.54 22.01 0.41 0.47 0.52 0.62 0.65 0.70 0.75 3.15 9.82 9.82 2.23 3.82 7.79 1.98 4.32 11.85 0.77 0.77 0.97 6.20 2.62 4.47 9.13 4.37 7.47 19.22 0.44 0.50 0.55 0.64 0.67 0.72 0.77 6.37 14.37 14.37 1.90 3.24 6.62 2.77 5.88 15.63 0.65 0.65 0.81 9.10 2.30 3.93 8.02 4.92 8.40 21.38 0.009416.00 Rainfall Intensity, I (in/hr) 0.01 0.00 25.6670.0000.00 Peak Flow, Q (cfs) Calculation of Peak Runoff using Rational Method Overland (Initial) Flow Time Channelized (Travel) Flow Time Time of ConcentrationRunoff Coefficient, C Subcatchment Name Area (ac) NRCS Hydrologic Soil Group Percent Imperviousness E1 2.17 C 2.0 Select UDFCD location for NOAA Atlas 14 Rainfall Depths from the pulldown list OR enter your own depths obtained from the NOAA website (click this link) Cells of this color are for required user-input Cells of this color are for optional override values Cells of this color are for calculated results based on overrides DAS LAMP RYNEARSON 6/6/2023 QT - Fort Collins Fort Collins, CO Version 2.00 released May 2017 20 0.06 0.00 A1 0.12 C 90.0 45.00 0.005 0.00 0.000 20 0.02 0.00 9.41 10.70 A3 0.44 C 98.0 190.00 0.018 10.00 0.010 20 2.00 0.08 10.70 A2 0.17 C 90.0 25.00 0.005 0.00 0.000 11.55 A5 0.14 C 79.0 103.00 0.024 0.00 0.000 20 0.01 0.00 0.000 20 0.06 0.000.024 0.00A4 0.13 C 85.0 100.00 20.71 A7 0.41 C 43.0 12.00 0.020 480.00 0.010 20 2.00 4.00 12.57 A6 0.09 C 35.0 20.00 0.010 145.00 0.070 15 3.97 0.61 32.01 Total A 2.32 C 55.0 20.00 0.020 800.00 0.010 20 2.00 6.67 24.02 A8 0.60 C 2.0 40.00 0.020 250.00 0.005 15 1.06 3.93 B1 0.03 C 2.0 15.00 0.250 0.00 0.000 10 0.03 0.00 24.63 25.66 Total B 0.07 C 2.0 50.00 0.050 0.00 0.000 15 0.15 0.00 25.66 B2 0.04 C 2.0 15.00 0.250 0.00 0.000 10 0.10 0.00 25.66 21.74 C2 0.08 C 100.0 12.00 0.020 300.00 0.005 20 1.41 3.54 C1 1.11 C 60.0 95.00 0.020 650.00 0.011 20 2.10 5.16 20.87 12.07 Total C 1.24 C 64.0 95.00 0.020 650.00 0.011 20 2.10 5.16 TOTAL SITE 3.36 C 56.0 100.00 0.050 1115.00 0.014 20 2.32 8.00 25.11 A+C Basins (Pond) 3.29 C 57.0 100.00 0.050 1115.00 0.014 20 2.32 8.00 25.98 A+B Basins 2.17 C 53.0 12.00 0.020 800.00 0.010 20 2.00 6.67 25.73 I /ℎ = a ∗P b + t t =0.395 1.1 − C L S. t =L 60K S = L 60V Computed t = t + t Regional t =26 − 17i + L 60 14i+ 9 S Selected t = max t34353 ,min Computed t ,Regional t t34353 =5 (urban) t34353 =10 (non-urban) Q 89: = CIA Project: Basin ID: Depth Increment = 0.10 ft Watershed Information Top of Micropool -- 0.00 -- -- -- 0 0.000 Selected BMP Type =EDB 4899 -- 0.10 -- -- -- 10 0.000 0 0.000 Watershed Area = 3.41 acres 4899.1 -- 0.20 -- -- -- 85 0.002 5 0.000 Watershed Length = 620 ft 4899.2 -- 0.30 -- -- -- 216 0.005 20 0.000 Watershed Length to Centroid = 508 ft 4899.3 -- 0.40 -- -- -- 450 0.010 54 0.001 Watershed Slope = 0.032 ft/ft 4899.4 -- 0.50 -- -- -- 873 0.020 120 0.003 Watershed Imperviousness = 58.00% percent 4899.5 -- 0.60 -- -- -- 1,405 0.032 234 0.005 Percentage Hydrologic Soil Group A = 0.0% percent 4899.6 -- 0.70 -- -- -- 1,683 0.039 388 0.009 Percentage Hydrologic Soil Group B = 0.0% percent 4899.7 -- 0.80 -- -- -- 2,015 0.046 573 0.013 Percentage Hydrologic Soil Groups C/D = 100.0% percent 4899.8 -- 0.90 -- -- -- 2,445 0.056 796 0.018 Target WQCV Drain Time = 40.0 hours 4899.9 -- 1.00 -- -- -- 3,002 0.069 1,068 0.025 Location for 1-hr Rainfall Depths = User Input 4900 -- 1.10 -- -- -- 3,733 0.086 1,405 0.032 4900.1 -- 1.20 -- -- -- 4,722 0.108 1,828 0.042 4900.2 -- 1.30 -- -- -- 6,218 0.143 2,375 0.055 Optional User Overrides 4900.3 -- 1.40 -- -- -- 7,747 0.178 3,073 0.071 Water Quality Capture Volume (WQCV) = 0.065 acre-feet acre-feet 4900.4 -- 1.50 -- -- -- 8,023 0.184 3,861 0.089 Excess Urban Runoff Volume (EURV) = 0.189 acre-feet acre-feet 4900.5 -- 1.60 -- -- -- 8,273 0.190 4,676 0.107 2-yr Runoff Volume (P1 = 0.82 in.) = 0.121 acre-feet 0.82 inches 4900.6 -- 1.70 -- -- -- 8,520 0.196 5,516 0.127 5-yr Runoff Volume (P1 = 1.14 in.) = 0.191 acre-feet 1.14 inches 4900.7 -- 1.80 -- -- -- 8,768 0.201 6,380 0.146 10-yr Runoff Volume (P1 = 1.4 in.) = 0.259 acre-feet 1.40 inches 4900.8 -- 1.90 -- -- -- 9,015 0.207 7,269 0.167 25-yr Runoff Volume (P1 = 1.81 in.) = 0.384 acre-feet 1.81 inches 4900.9 -- 2.00 -- -- -- 9,261 0.213 8,183 0.188 50-yr Runoff Volume (P1 = 2.27 in.) = 0.516 acre-feet 2.27 inches 4901 -- 2.10 -- -- -- 9,507 0.218 9,122 0.209 100-yr Runoff Volume (P1 = 2.86 in.) = 0.697 acre-feet 2.86 inches 4901.1 -- 2.20 -- -- -- 9,751 0.224 10,084 0.232 500-yr Runoff Volume (P1 = 4.39 in.) = 1.156 acre-feet 4.39 inches 4901.2 -- 2.30 -- -- -- 9,995 0.229 11,072 0.254 Approximate 2-yr Detention Volume = 0.116 acre-feet 4901.3 -- 2.40 -- -- -- 10,240 0.235 12,083 0.277 Approximate 5-yr Detention Volume = 0.185 acre-feet 4901.4 -- 2.50 -- -- -- 10,485 0.241 13,120 0.301 Approximate 10-yr Detention Volume = 0.222 acre-feet 4901.5 -- 2.60 -- -- -- 10,732 0.246 14,181 0.326 Approximate 25-yr Detention Volume = 0.270 acre-feet 4901.6 -- 2.70 -- -- -- 10,979 0.252 15,266 0.350 Approximate 50-yr Detention Volume = 0.311 acre-feet 4901.7 -- 2.80 -- -- -- 11,227 0.258 16,376 0.376 Approximate 100-yr Detention Volume = 0.389 acre-feet 4901.8 -- 2.90 -- -- -- 11,477 0.263 17,512 0.402 4901.9 -- 3.00 -- -- -- 11,729 0.269 18,672 0.429 Define Zones and Basin Geometry 4902 -- 3.10 -- -- -- 11,999 0.275 19,858 0.456 Zone 1 Volume (WQCV) = 0.065 acre-feet 4902.1 -- 3.20 -- -- -- 12,303 0.282 21,073 0.484 Zone 2 Volume (2-year - Zone 1) = 0.051 acre-feet 4902.2 -- 3.30 -- -- -- 12,633 0.290 22,320 0.512 Zone 3 Volume (100-year - Zones 1 & 2) = 0.272 acre-feet 4902.3 -- 3.40 -- -- -- 12,994 0.298 23,602 0.542 Total Detention Basin Volume = 0.389 acre-feet 4902.4 -- 3.50 -- -- -- 13,386 0.307 24,921 0.572 Initial Surcharge Volume (ISV) = user ft 3 4902.5 -- 3.60 -- -- -- 13,811 0.317 26,280 0.603 Initial Surcharge Depth (ISD) = user ft 4902.6 -- 3.70 -- -- -- 14,270 0.328 27,684 0.636 Total Available Detention Depth (Htotal) =user ft 4902.7 -- 3.80 -- -- -- 14,762 0.339 29,136 0.669 Depth of Trickle Channel (HTC) =user ft 4902.8 -- 3.90 -- -- -- 15,290 0.351 30,639 0.703 Slope of Trickle Channel (STC) =user ft/ft 4902.9 -- 4.00 -- -- -- 15,857 0.364 32,196 0.739 Slopes of Main Basin Sides (Smain) =user H:V 4903 -- 4.10 -- -- -- 16,460 0.378 33,812 0.776 Basin Length-to-Width Ratio (RL/W) =user -- -- -- -- -- -- -- -- Initial Surcharge Area (AISV) =user ft 2 -- -- -- -- Surcharge Volume Length (LISV) =user ft -- -- -- -- Surcharge Volume Width (WISV) =user ft -- -- -- -- Depth of Basin Floor (HFLOOR) =user ft -- -- -- -- Length of Basin Floor (LFLOOR) =user ft -- -- -- -- Width of Basin Floor (WFLOOR) =user ft -- -- -- -- Area of Basin Floor (AFLOOR) =user ft 2 -- -- -- -- Volume of Basin Floor (VFLOOR) =user ft 3 -- -- -- -- Depth of Main Basin (HMAIN) =user ft -- -- -- -- Length of Main Basin (LMAIN) =user ft -- -- -- -- Width of Main Basin (WMAIN) =user ft -- -- -- -- Area of Main Basin (AMAIN) =user ft 2 -- -- -- -- Volume of Main Basin (VMAIN) =user ft 3 -- -- -- -- Calculated Total Basin Volume (Vtotal) =user acre-feet -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- After providing required inputs above including 1-hour rainfall depths, click 'Run CUHP' to generate runoff hydrographs using the embedded Colorado Urban Hydrograph Procedure. Volume (ft 3) Volume (ac-ft) Area (acre) DETENTION BASIN STAGE-STORAGE TABLE BUILDER Optional Override Area (ft 2) Length (ft) Optional Override Stage (ft) Stage (ft) Stage - Storage Description Area (ft 2) Width (ft) MHFD-Detention, Version 4.04 (February 2021) Example Zone Configuration (Retention Pond) QT Fort Collins - MHFD-Detention_v4 04.xlsm, Basin 6/6/2023, 1:05 PM 1 User Defined Stage-Area Booleans for Message 1 Equal Stage-Area Inputs Watershed L:W 1 CountA Watershed Lc:L Watershed Slope 0 Calc_S_TC Booleans for CUHP 1 CUHP Inputs Complete H_FLOOR 1 CUHP Results Calculated L_FLOOR_OTHER 0.00 ISV 0.00 ISV 0.00 Floor 0.00 Floor 1.37 Zone 1 (WQCV) 1.37 Zone 1 (WQCV) 1.65 Zone 2 (2-year) 1.65 Zone 2 (2-year) 2.85 Zone 3 (100-year)2.85 Zone 3 (100-year) DETENTION BASIN STAGE-STORAGE TABLE BUILDER MHFD-Detention, Version 4.04 (February 2021) 0.000 0.195 0.390 0.585 0.780 0.000 0.095 0.190 0.285 0.380 0.00 1.50 3.00 4.50 6.00 Volume (ac-ft)Area (acres)Stage (ft.) Area (acres)Volume (ac-ft) 0 4200 8400 12600 16800 0 5 10 15 20 0.00 1.50 3.00 4.50 6.00 Area (sq.ft.)Length, Width (ft.)Stage (ft) Length (ft)Width (ft)Area (sq.ft.) QT Fort Collins - MHFD-Detention_v4 04.xlsm, Basin 6/6/2023, 1:05 PM Project: Basin ID: Estimated Estimated Stage (ft) Volume (ac-ft) Outlet Type Zone 1 (WQCV) 1.37 0.065 Orifice Plate Zone 2 (2-year) 1.65 0.051 Circular Orifice Zone 3 (100-year) 2.85 0.272 Weir&Pipe (Restrict) Total (all zones) 0.389 User Input: Orifice at Underdrain Outlet (typically used to drain WQCV in a Filtration BMP)Calculated Parameters for Underdrain Underdrain Orifice Invert Depth = N/A ft (distance below the filtration media surface) Underdrain Orifice Area = N/A ft2 Underdrain Orifice Diameter = N/A inches Underdrain Orifice Centroid = N/A feet User Input: Orifice Plate with one or more orifices or Elliptical Slot Weir (typically used to drain WQCV and/or EURV in a sedimentation BMP)Calculated Parameters for Plate Invert of Lowest Orifice = 0.00 ft (relative to basin bottom at Stage = 0 ft) WQ Orifice Area per Row = 2.569E-03 ft2 Depth at top of Zone using Orifice Plate = 1.40 ft (relative to basin bottom at Stage = 0 ft) Elliptical Half-Width = N/A feet Orifice Plate: Orifice Vertical Spacing = N/A inches Elliptical Slot Centroid = N/A feet Orifice Plate: Orifice Area per Row = 0.37 sq. inches (diameter = 11/16 inch)Elliptical Slot Area = N/A ft2 User Input: Stage and Total Area of Each Orifice Row (numbered from lowest to highest) Row 1 (required) Row 2 (optional) Row 3 (optional) Row 4 (optional) Row 5 (optional) Row 6 (optional) Row 7 (optional) Row 8 (optional) Stage of Orifice Centroid (ft) 0.00 0.60 1.20 Orifice Area (sq. inches) 0.37 0.37 0.37 Row 9 (optional) Row 10 (optional) Row 11 (optional) Row 12 (optional) Row 13 (optional) Row 14 (optional) Row 15 (optional) Row 16 (optional) Stage of Orifice Centroid (ft) Orifice Area (sq. inches) User Input: Vertical Orifice (Circular or Rectangular)Calculated Parameters for Vertical Orifice Zone 2 Circular Not Selected Zone 2 Circular Not Selected Invert of Vertical Orifice = 1.40 N/A ft (relative to basin bottom at Stage = 0 ft) Vertical Orifice Area = 0.01 N/A ft2 Depth at top of Zone using Vertical Orifice = 2.10 N/A ft (relative to basin bottom at Stage = 0 ft) Vertical Orifice Centroid = 0.04 N/A feet Vertical Orifice Diameter = 1.00 N/A inches User Input: Overflow Weir (Dropbox with Flat or Sloped Grate and Outlet Pipe OR Rectangular/Trapezoidal Weir (and No Outlet Pipe) Calculated Parameters for Overflow Weir grate Zone 3 Weir Not Selected Zone 3 Weir Not Selected Overflow Weir Front Edge Height, Ho = 2.10 N/A ft (relative to basin bottom at Stage = 0 ft)Height of Grate Upper Edge, Ht =2.85 N/A feet Overflow Weir Front Edge Length = 3.00 N/A feet Overflow Weir Slope Length = 3.09 N/A feet Overflow Weir Grate Slope = 4.00 N/A H:V Grate Open Area / 100-yr Orifice Area = 3.65 N/A Horiz. Length of Weir Sides = 3.00 N/A feet Overflow Grate Open Area w/o Debris = 6.46 N/A ft2 Overflow Grate Type = Type C Grate Type C Grate Overflow Grate Open Area w/ Debris = 3.23 N/A ft2 Debris Clogging % = 50% N/A % User Input: Outlet Pipe w/ Flow Restriction Plate (Circular Orifice, Restrictor Plate, or Rectangular Orifice)Calculated Parameters for Outlet Pipe w/ Flow Restriction Plate Zone 3 Restrictor Not Selected Zone 3 Restrictor Not Selected Depth to Invert of Outlet Pipe = 0.00 N/A ft (distance below basin bottom at Stage = 0 ft)Outlet Orifice Area = 1.77 N/A ft2 Outlet Pipe Diameter = 18.00 N/A inches Outlet Orifice Centroid = 0.75 N/A feet Restrictor Plate Height Above Pipe Invert = 18.00 inches Half-Central Angle of Restrictor Plate on Pipe =3.14 N/A radians User Input: Emergency Spillway (Rectangular or Trapezoidal)Calculated Parameters for Spillway Spillway Invert Stage= ft (relative to basin bottom at Stage = 0 ft) Spillway Design Flow Depth= feet Spillway Crest Length = feet Stage at Top of Freeboard = feet Spillway End Slopes = H:V Basin Area at Top of Freeboard = acres Freeboard above Max Water Surface = feet Basin Volume at Top of Freeboard = acre-ft Max Ponding Depth of Target Storage Volume =3.00 feet Discharge at Top of Freeboard =cfs Routed Hydrograph Results Design Storm Return Period =WQCV EURV 2 Year 5 Year 10 Year 25 Year 50 Year 100 Year 500 Year One-Hour Rainfall Depth (in) =N/A N/A 0.82 1.14 1.40 1.81 2.27 2.86 4.39 CUHP Runoff Volume (acre-ft) =0.065 0.189 0.121 0.191 0.259 0.384 0.516 0.697 1.156 Inflow Hydrograph Volume (acre-ft) =N/A N/A 0.121 0.191 0.259 0.384 0.516 0.697 1.156 CUHP Predevelopment Peak Q (cfs) =N/A N/A 0.0 0.4 0.9 2.2 3.3 5.0 8.9 OPTIONAL Override Predevelopment Peak Q (cfs) =N/A N/A Predevelopment Unit Peak Flow, q (cfs/acre) =N/A N/A 0.01 0.11 0.26 0.64 0.98 1.46 2.60 Peak Inflow Q (cfs) =N/A N/A 1.7 2.7 3.7 5.7 7.7 10.4 16.9 Peak Outflow Q (cfs) =0.0 0.1 0.0 0.1 0.2 1.1 2.3 4.3 9.1 Ratio Peak Outflow to Predevelopment Q =N/A N/A N/A 0.2 0.2 0.5 0.7 0.9 1.0 Structure Controlling Flow =Plate Vertical Orifice 1 Vertical Orifice 1 Vertical Orifice 1 Overflow Weir 1 Overflow Weir 1 Overflow Weir 1 Overflow Weir 1 Overflow Weir 1 Max Velocity through Grate 1 (fps) =N/A N/A N/A N/A 0.0 0.2 0.3 0.7 1.4 Max Velocity through Grate 2 (fps) =N/A N/A N/A N/A N/A N/A N/A N/A N/A Time to Drain 97% of Inflow Volume (hours) =39 65 54 66 73 71 68 65 57 Time to Drain 99% of Inflow Volume (hours) =41 70 57 71 79 78 77 75 72 Maximum Ponding Depth (ft) =1.37 2.01 1.63 1.97 2.23 2.52 2.74 3.00 3.46 Area at Maximum Ponding Depth (acres) =0.17 0.21 0.19 0.21 0.23 0.24 0.25 0.27 0.30 Maximum Volume Stored (acre-ft) =0.065 0.190 0.113 0.179 0.238 0.304 0.361 0.429 0.560 DETENTION BASIN OUTLET STRUCTURE DESIGN MHFD-Detention, Version 4.04 (February 2021) The user can override the default CUHP hydrographs and runoff volumes by entering new values in the Inflow Hydrographs table (Columns W through AF). Example Zone Configuration (Retention Pond) QT Fort Collins - MHFD-Detention_v4 04.xlsm, Outlet Structure 6/6/2023, 1:06 PM COUNTA for Basin Tab =1 Ao Dia WQ Plate Type Vert Orifice 1Vert Orifice 2 Count_Underdrain = 0 0.11(diameter = 3/8 inch)2 2 1 Count_WQPlate = 1 0.14(diameter = 7/16 inch) Count_VertOrifice1 = 1 0.18(diameter = 1/2 inch)Outlet Plate 1 Outlet Plate 2 Drain Time Message Boolean Count_VertOrifice2 = 0 0.24(diameter = 9/16 inch)4 1 5yr, <72hr 0 Count_Weir1 = 1 0.29(diameter = 5/8 inch)>5yr, <120hr 0 Count_Weir2 = 0 0.36(diameter = 11/16 inch)Max Depth Row Count_OutletPipe1 = 1 0.42(diameter = 3/4 inch)WQCV 138 Watershed Constraint Check Count_OutletPipe2 = 0 0.50(diameter = 13/16 inch)2 Year 164 Slope 0.032 COUNTA_2 (Standard FSD Setup)= 1 0.58(diameter = 7/8 inch)EURV 202 Shape 2.59 Hidden Parameters & Calculations 0.67(diameter = 15/16 inch)5 Year 198 MaxPondDepth_Error? FALSE 0.76 (diameter = 1 inch)10 Year 224 Spillway Depth Cd_Broad-Crested Weir 3.00 0.86(diameter = 1-1/16 inches)25 Year 253 WQ Plate Flow at 100yr depth = 0.06 0.97(diameter = 1-1/8 inches)50 Year 275 CLOG #1= 50% 1.08(diameter = 1-3/16 inches)100 Year 301 1 Z1_Boolean n*Cdw #1 = 0.32 1.20(diameter = 1-1/4 inches)500 Year 347 1 Z2_Boolean n*Cdo #1 = 1.45 1.32(diameter = 1-5/16 inches)Zone3_Pulldown Message 1 Z3_Boolean Overflow Weir #1 Angle = 0.245 1.45(diameter = 1-3/8 inches)1 Opening Message CLOG #2= N/A 1.59(diameter = 1-7/16 inches)Draintime Running n*Cdw #2 = N/A 1.73(diameter = 1-1/2 inches)Outlet Boolean Outlet Rank Total (1 to 4) n*Cdo #2 = N/A 1.88(diameter = 1-9/16 inches)Vertical Orifice 1 1 1 2 Overflow Weir #2 Angle = N/A 2.03(diameter = 1-5/8 inches)Vertical Orifice 2 0 0 Boolean Underdrain Q at 100yr depth = 0.00 2.20(diameter = 1-11/16 inches)Overflow Weir 1 1 2 0 Max Depth VertOrifice1 Q at 100yr depth = 0.03 2.36(diameter = 1-3/4 inches)Overflow Weir 2 0 0 0 500yr Depth VertOrifice2 Q at 100yr depth = 0.00 2.54(diameter = 1-13/16 inches)Outlet Pipe 1 1 2 0 Freeboard 2.72(diameter = 1-7/8 inches)Outlet Pipe 2 0 0 0 Spillway Count_User_Hydrographs 0 2.90(diameter = 1-15/16 inches)0 Spillway Length CountA_3 (EURV & 100yr) = 1 3.09(diameter = 2 inches)FALSE Time Interval CountA_4 (100yr Only) = 1 3.29(use rectangular openings)Button Visibility Boolean COUNTA_5 (FSD Weir Only)= 0 0 WQCV Underdrain COUNTA_6 (EURV Weir Only)= 1 1 WQCV Plate 0 EURV-WQCV Plate Outlet1_Pulldown_Boolean 0 EURV-WQCV VertOriice Outlet2_Pulldown_Boolean 0 Outlet 90% Qpeak Outlet3_Pulldown_Boolean 0 Outlet Undetained 0 Weir Only 90% Qpeak 0 Five Year Ratio Plate 0 Five Year Ratio VertOrifice EURV_draintime_user Spillway Options Offset Overlapping Overflow Weir 1 S-A-V-D Chart Axis Default X-axis Left Y-Axis Right Y-Axis minimum bound 0.00 0 0 maximum bound 4.00 30,000 10 S-A-V-D Chart Axis Override X-axis Left Y-Axis Right Y-Axis minimum bound maximum bound DETENTION BASIN OUTLET STRUCTURE DESIGN MHFD-Detention, Version 4.04 (February 2021) 0 2 4 6 8 10 12 14 16 18 0.1 1 10FLOW [cfs]TIME [hr] 500YR IN 500YR OUT 100YR IN 100YR OUT 50YR IN 50YR OUT 25YR IN 25YR OUT 10YR IN 10YR OUT 5YR IN 5YR OUT 2YR IN 2YR OUT EURV IN EURV OUT WQCV IN WQCV OUT 0 0.5 1 1.5 2 2.5 3 3.5 4 0.1 1 10 100PONDING DEPTH [ft]DRAIN TIME [hr] 500YR 100YR 50YR 25YR 10YR 5YR 2YR EURV WQCV 0 1 2 3 4 5 6 7 8 9 10 0 5,000 10,000 15,000 20,000 25,000 30,000 0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 4.00 OUTFLOW [cfs]AREA [ft^2], VOLUME [ft^3]PONDING DEPTH [ft] User Area [ft^2] Interpolated Area [ft^2] Summary Area [ft^2] Volume [ft^3] Summary Volume [ft^3] Outflow [cfs] Summary Outflow [cfs] QT Fort Collins - MHFD-Detention_v4 04.xlsm, Outlet Structure 6/6/2023, 1:06 PM Outflow Hydrograph Workbook Filename: Inflow Hydrographs The user can override the calculated inflow hydrographs from this workbook with inflow hydrographs developed in a separate program. SOURCE CUHP CUHP CUHP CUHP CUHP CUHP CUHP CUHP CUHP Time Interval TIME WQCV [cfs] EURV [cfs] 2 Year [cfs] 5 Year [cfs] 10 Year [cfs] 25 Year [cfs] 50 Year [cfs] 100 Year [cfs] 500 Year [cfs] 5.00 min 0:00:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0:05:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0:10:00 0.00 0.00 0.00 0.00 0.00 0.00 0.04 0.06 0.31 0:15:00 0.00 0.00 0.07 0.26 0.38 0.31 0.49 0.58 1.09 0:20:00 0.00 0.00 0.59 0.92 1.18 0.86 1.16 1.46 2.76 0:25:00 0.00 0.00 1.35 2.16 3.04 1.99 2.84 3.81 7.05 0:30:00 0.00 0.00 1.71 2.75 3.72 4.92 6.75 8.75 14.56 0:35:00 0.00 0.00 1.62 2.59 3.46 5.71 7.67 10.37 16.89 0:40:00 0.00 0.00 1.48 2.31 3.09 5.59 7.46 10.03 16.25 0:45:00 0.00 0.00 1.29 2.04 2.76 5.05 6.72 9.29 15.02 0:50:00 0.00 0.00 1.13 1.82 2.41 4.63 6.16 8.46 13.68 0:55:00 0.00 0.00 0.99 1.58 2.11 4.02 5.36 7.53 12.17 1:00:00 0.00 0.00 0.88 1.39 1.87 3.48 4.64 6.70 10.84 1:05:00 0.00 0.00 0.80 1.26 1.71 3.05 4.09 6.06 9.82 1:10:00 0.00 0.00 0.72 1.17 1.60 2.65 3.57 5.17 8.44 1:15:00 0.00 0.00 0.64 1.05 1.49 2.32 3.15 4.43 7.27 1:20:00 0.00 0.00 0.56 0.92 1.31 1.97 2.67 3.64 5.99 1:25:00 0.00 0.00 0.50 0.80 1.10 1.66 2.23 2.94 4.86 1:30:00 0.00 0.00 0.43 0.69 0.92 1.34 1.80 2.33 3.87 1:35:00 0.00 0.00 0.38 0.61 0.78 1.07 1.42 1.80 3.04 1:40:00 0.00 0.00 0.35 0.53 0.70 0.86 1.15 1.42 2.44 1:45:00 0.00 0.00 0.34 0.48 0.65 0.73 0.98 1.19 2.08 1:50:00 0.00 0.00 0.33 0.44 0.61 0.65 0.88 1.03 1.84 1:55:00 0.00 0.00 0.30 0.41 0.58 0.60 0.80 0.93 1.67 2:00:00 0.00 0.00 0.26 0.38 0.53 0.56 0.75 0.85 1.54 2:05:00 0.00 0.00 0.21 0.30 0.41 0.44 0.58 0.64 1.17 2:10:00 0.00 0.00 0.16 0.23 0.31 0.33 0.44 0.47 0.87 2:15:00 0.00 0.00 0.12 0.17 0.24 0.25 0.33 0.35 0.65 2:20:00 0.00 0.00 0.09 0.13 0.18 0.19 0.25 0.27 0.49 2:25:00 0.00 0.00 0.07 0.10 0.13 0.14 0.18 0.20 0.37 2:30:00 0.00 0.00 0.05 0.07 0.10 0.10 0.14 0.15 0.27 2:35:00 0.00 0.00 0.04 0.05 0.07 0.08 0.10 0.11 0.20 2:40:00 0.00 0.00 0.03 0.04 0.05 0.06 0.07 0.08 0.15 2:45:00 0.00 0.00 0.02 0.03 0.04 0.04 0.05 0.06 0.10 2:50:00 0.00 0.00 0.01 0.02 0.02 0.03 0.03 0.04 0.07 2:55:00 0.00 0.00 0.01 0.01 0.01 0.01 0.02 0.02 0.04 3:00:00 0.00 0.00 0.00 0.00 0.01 0.01 0.01 0.01 0.02 3:05:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3:10:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3:15:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3:20:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3:25:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3:30:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3:35:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3:40:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3:45:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3:50:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3:55:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 4:00:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 4:05:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 4:10:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 4:15:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 4:20:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 4:25:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 4:30:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 4:35:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 4:40:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 4:45:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 4:50:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 4:55:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 5:00:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 5:05:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 5:10:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 5:15:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 5:20:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 5:25:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 5:30:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 5:35:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 5:40:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 5:45:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 5:50:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 5:55:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 6:00:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 DETENTION BASIN OUTLET STRUCTURE DESIGN QT Fort Collins - MHFD-Detention_v4 04.xlsm, Outlet Structure 6/6/2023, 1:06 PM Summary Stage-Area-Volume-Discharge Relationships The user can create a summary S-A-V-D by entering the desired stage increments and the remainder of the table will populate automatically. The user should graphically compare the summary S-A-V-D table to the full S-A-V-D table in the chart to confirm it captures all key transition points. Stage Area Area Volume Volume Total Outflow [ft][ft 2][acres][ft 3][ac-ft] [cfs] 1.37 7,288 0.167 2,847 0.065 0.03 1.62 8,322 0.191 4,842 0.111 0.05 2.22 9,800 0.225 10,280 0.236 0.19 3.00 11,729 0.269 18,672 0.429 4.30 For best results, include the stages of all grade slope changes (e.g. ISV and Floor) from the S-A-V table on Sheet 'Basin'. Also include the inverts of all outlets (e.g. vertical orifice, overflow grate, and spillway, where applicable). DETENTION BASIN OUTLET STRUCTURE DESIGN Stage - Storage Description WQCV (Elev. = 4890.3) 2-Year (Elev. = 4890.5) 10-Year (Elev. = 4901.1) 100-Year (Elev. = 4901.9) MHFD-Detention, Version 4.04 (February 2021) QT Fort Collins - MHFD-Detention_v4 04.xlsm, Outlet Structure 6/6/2023, 1:06 PM Sheet 1 of 2 Designer: Company: Date: Project: Location: 1. Basin Storage Volume A) Effective Imperviousness of Tributary Area, Ia Ia =75.0 % (100% if all paved and roofed areas upstream of rain garden) B) Tributary Area's Imperviousness Ratio (i = Ia/100)i = 0.750 C) Water Quality Capture Volume (WQCV) for a 12-hour Drain Time WQCV = 0.24 watershed inches (WQCV= 0.8 * (0.91* i3 - 1.19 * i2 + 0.78 * i) D) Contributing Watershed Area (including rain garden area) Area = 21,452 sq ft E) Water Quality Capture Volume (WQCV) Design Volume VWQCV =cu ft Vol = (WQCV / 12) * Area F) For Watersheds Outside of the Denver Region, Depth of d6 =0.86 in Average Runoff Producing Storm G) For Watersheds Outside of the Denver Region, VWQCV OTHER =857 cu ft Water Quality Capture Volume (WQCV) Design Volume H) User Input of Water Quality Capture Volume (WQCV) Design Volume VWQCV USER =cu ft (Only if a different WQCV Design Volume is desired) 2. Basin Geometry A) WQCV Depth (12-inch maximum)DWQCV =12 in B) Rain Garden Side Slopes (Z = 4 min., horiz. dist per unit vertical) Z = 4.00 ft / ft (Use "0" if rain garden has vertical walls) C) Mimimum Flat Surface Area AMin =322 sq ft D) Actual Flat Surface Area AActual =467 sq ft E) Area at Design Depth (Top Surface Area)ATop =1486 sq ft F) Rain Garden Total Volume VT=977 cu ft (VT= ((ATop + AActual) / 2) * Depth) 3. Growing Media 4. Underdrain System A) Are underdrains provided?1 B) Underdrain system orifice diameter for 12 hour drain time i) Distance From Lowest Elevation of the Storage y =1.0 ft Volume to the Center of the Orifice ii) Volume to Drain in 12 Hours Vol12 =857 cu ft iii) Orifice Diameter, 3/8" Minimum DO =3/4 in Design Procedure Form: Rain Garden (RG) DAS Lamp Rynearson June 6, 2023 QuikTrip Fort Collins - Rain Garden A Fort Collins Colorado UD-BMP (Version 3.07, March 2018) Choose One Choose One 18" Rain Garden Growing Media Other (Explain): YES NO UD-BMP_v3.07 - Rain Garden Pond A.xlsm, RG 6/6/2023, 11:51 AM Sheet 2 of 2 Designer: Company: Date: Project: Location: 5. Impermeable Geomembrane Liner and Geotextile Separator Fabric A) Is an impermeable liner provided due to proximity of structures or groundwater contamination? 6. Inlet / Outlet Control A) Inlet Control 7. Vegetation 8. Irrigation A) Will the rain garden be irrigated? Notes: Design Procedure Form: Rain Garden (RG) DAS Lamp Rynearson June 6, 2023 QuikTrip Fort Collins - Rain Garden A Fort Collins Colorado Choose One Choose One Choose One Sheet Flow- No Energy Dissipation Required Concentrated Flow- Energy Dissipation Provided Plantings Seed (Plan for frequent weed control) Sand Grown or Other High Infiltration Sod Choose One YES NO YES NO UD-BMP_v3.07 - Rain Garden Pond A.xlsm, RG 6/6/2023, 11:51 AM Sheet 1 of 2 Designer: Company: Date: Project: Location: 1. Basin Storage Volume A) Effective Imperviousness of Tributary Area, Ia Ia =61.0 % (100% if all paved and roofed areas upstream of rain garden) B) Tributary Area's Imperviousness Ratio (i = Ia/100)i = 0.610 C) Water Quality Capture Volume (WQCV) for a 12-hour Drain Time WQCV = 0.19 watershed inches (WQCV= 0.8 * (0.91* i3 - 1.19 * i2 + 0.78 * i) D) Contributing Watershed Area (including rain garden area) Area = 48,281 sq ft E) Water Quality Capture Volume (WQCV) Design Volume VWQCV =cu ft Vol = (WQCV / 12) * Area F) For Watersheds Outside of the Denver Region, Depth of d6 =0.86 in Average Runoff Producing Storm G) For Watersheds Outside of the Denver Region, VWQCV OTHER =1,539 cu ft Water Quality Capture Volume (WQCV) Design Volume H) User Input of Water Quality Capture Volume (WQCV) Design Volume VWQCV USER =cu ft (Only if a different WQCV Design Volume is desired) 2. Basin Geometry A) WQCV Depth (12-inch maximum)DWQCV =12 in B) Rain Garden Side Slopes (Z = 4 min., horiz. dist per unit vertical) Z = 4.00 ft / ft (Use "0" if rain garden has vertical walls) C) Mimimum Flat Surface Area AMin =589 sq ft D) Actual Flat Surface Area AActual =1103 sq ft E) Area at Design Depth (Top Surface Area)ATop =2023 sq ft F) Rain Garden Total Volume VT=1,563 cu ft (VT= ((ATop + AActual) / 2) * Depth) 3. Growing Media 4. Underdrain System A) Are underdrains provided?1 B) Underdrain system orifice diameter for 12 hour drain time i) Distance From Lowest Elevation of the Storage y =10.0 ft Volume to the Center of the Orifice ii) Volume to Drain in 12 Hours Vol12 =1,539 cu ft iii) Orifice Diameter, 3/8" Minimum DO =5/8 in Design Procedure Form: Rain Garden (RG) DAS Lamp Rynearson June 6, 2023 QuikTrip Fort Collins - Rain Garden B Fort Collins Colorado UD-BMP (Version 3.07, March 2018) Choose One Choose One 18" Rain Garden Growing Media Other (Explain): YES NO UD-BMP_v3.07.xlsm, RG 6/6/2023, 11:52 AM Sheet 2 of 2 Designer: Company: Date: Project: Location: 5. Impermeable Geomembrane Liner and Geotextile Separator Fabric A) Is an impermeable liner provided due to proximity of structures or groundwater contamination? 6. Inlet / Outlet Control A) Inlet Control 7. Vegetation 8. Irrigation A) Will the rain garden be irrigated? Notes: Design Procedure Form: Rain Garden (RG) DAS Lamp Rynearson June 6, 2023 QuikTrip Fort Collins - Rain Garden B Fort Collins Colorado Choose One Choose One Choose One Sheet Flow- No Energy Dissipation Required Concentrated Flow- Energy Dissipation Provided Plantings Seed (Plan for frequent weed control) Sand Grown or Other High Infiltration Sod Choose One YES NO YES NO UD-BMP_v3.07.xlsm, RG 6/6/2023, 11:52 AM Sheet 1 of 1 Designer: Company: Date: Project: Location: 1. Design Discharge for 2-Year Return Period Q2 =1.26 cfs 2. Hydraulic Residence Time A) : Length of Grass Swale LS =150.0 ft B) Calculated Residence Time (based on design velocity below)THR= 2.6 minutes 3. Longitudinal Slope (vertical distance per unit horizontal) A) Available Slope (based on site constraints)Savail =0.008 ft / ft B) Design Slope SD =0.008 ft / ft 4. Swale Geometry A) Channel Side Slopes (Z = 4 min., horiz. distance per unit vertical) Z = 4.00 ft / ft B) Bottom Width of Swale (enter 0 for triangular section)WB =0.00 ft 5. Vegetation A) Type of Planting (seed vs. sod, affects vegetal retardance factor) 6. Design Velocity (0.5 ft / s maximum for desirable 5-minute residence time)V2 =0.97 ft / s 7.Design Flow Depth (1 foot maximum)D2 =0.57 ft A) Flow Area A2 =1.3 sq ft B) Top Width of Swale WT =4.6 ft C) Froude Number (0.50 maximum)F = 0.32 D) Hydraulic Radius RH = 0.28 E) Velocity-Hydraulic Radius Product for Vegetal Retardance VR = 0.27 F) Manning's n (based on SCS vegetal retardance curve E for seeded grass) n = 0.057 G) Cumulative Height of Grade Control Structures Required HD =0.00 ft AN UNDERDRAIN IS 8. Underdrain REQUIRED IF THE (Is an underdrain necessary?)DESIGN SLOPE < 2.0% 9. Soil Preparation (Describe soil amendment) 10. Irrigation Notes: Design Procedure Form: Grass Swale (GS) DAS Lamp Rynearson June 6, 2023 QuikTrip Fort Collins Fort Collins, Colorado UD-BMP (Version 3.07, March 2018) Choose One Temporary Permanent Choose One Grass From Seed Grass From Sod Choose One YES NO UD-BMP_v3.07 - Rain Garden Pond B & Bio Swale.xlsm, GS 6/6/2023, 2:34 PM Weir Report Hydraflow Express Extension for Autodesk® Civil 3D® by Autodesk, Inc.Monday, Jun 5 2023 QuikTrip Fort Collins Full Spectrum Detention Pond Spillway Trapezoidal Weir Crest = Sharp Bottom Length (ft) = 18.50 Total Depth (ft) = 1.00 Side Slope (z:1) = 4.00 Calculations Weir Coeff. Cw = 3.10 Compute by: Known Q Known Q (cfs) = 21.70 Highlighted Depth (ft) = 0.50 Q (cfs) = 21.70 Area (sqft) = 10.25 Velocity (ft/s) = 2.12 Top Width (ft) = 22.50 0 5 10 15 20 25 30 35 40 Depth (ft)Depth (ft)QuikTrip Fort Collins Full Spectrum Detention Pond Spillway -0.50 -0.50 0.00 0.00 0.50 0.50 1.00 1.00 1.50 1.50 2.00 2.00 Length (ft)Weir W.S.