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HomeMy WebLinkAboutReports - Drainage - 04/21/2025i FINAL DRAINAGE REPORT FOR POLESTAR VILLAGE Prepared For: POLESTAR GARDEN, INC PO BOX 211582 FORT COLLINS, COLORADO 80521 Michael Gornik (808) 443-9956 April 21th, 2025 Project No. 39797.01 Prepared By: JR Engineering, LLC 2900 South College Avenue, Suite 1A Fort Collins, CO 80525 ii ii TABLE OF CONTENTS TABLE OF CONTENTS ......................................................................................................................... ii APPENDIX ..................................................................................................................................... iii Engineer’s Certification Block ........................................................................................................... iii GENERAL DESCRIPTION AND LOCATION ............................................................................................ 1 LOCATION ..................................................................................................................................... 1 DESCRIPTION OF PROPERTY .......................................................................................................... 1 MASTER DRAINAGE BASIN DESCRIPTION ....................................................................................... 1 FLOODPLAIN SUBMITTAL REQUIREMENTS ..................................................................................... 2 DRAINAGE BASINS AND SUB-BASINS ................................................................................................. 2 MAJOR BASINS AND SUB-BASINS ................................................................................................... 2 EXISTING SUB-BASIN DESCRIPTION ................................................................................................ 2 EXISTING OFFSITE DRAINAGE BASINS ............................................................................................ 3 EXISTING OFFSITE DRAINAGE DESCRIPTIONS ................................................................................. 3 PROPOSED SUB-BASINS DESCRIPTIONS ......................................................................................... 4 PROJECT DESCRIPTION ...................................................................................................................... 9 PROJECT DESCRIPTION .................................................................................................................. 9 PROPOSED DRAINAGE FACILITIES ...................................................................................................... 9 GENERAL CONCEPT ....................................................................................................................... 9 WATER QUALITY/ DETENTION FACILITIES ...................................................................................... 9 LOW IMPACT DEVELOPMENT ...................................................................................................... 10 DRAINAGE DESIGN CRITERIA ........................................................................................................... 10 REGULATIONS ............................................................................................................................. 10 FOUR STEP PROCESS TO PROTECT RECEIVING WATERS ............................................................... 10 DEVELOPMENT CRITERIA REFERENCE AND CONSTRAINTS ........................................................... 11 HYDROLOGIC CRITERIA ................................................................................................................ 13 HYDRAULIC CRITERIA ................................................................................................................... 14 FLOODPLAIN REGULATIONS COMPLIANCE ................................................................................... 15 MODIFICATIONS OF CRITERIA ...................................................................................................... 15 EROSION CONTROL ..................................................................................................................... 15 CONCLUSIONS ................................................................................................................................. 16 COMPLIANCE WITH STANDARDS ................................................................................................. 16 DRAINAGE CONCEPT ................................................................................................................... 16 REFERENCES .................................................................................................................................... 17 iii iii APPENDIX Appendix A – Figures Appendix B – Hydrologic Calculations Appendix C – Hydraulic Calculations Appendix D – Water Quality Calculations Appendix E – Reference Appendix F – Maps Appendix G – LID Exhibit Engineer’s Certification Block I hereby attest that this report for the final drainage design for the Polestar Village 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. Joseph Martin Frank, PE Registered Professional Engineer State of Colorado No. 53399 1 GENERAL DESCRIPTION AND LOCATION LOCATION The site is located in The Northwest Quarter of Section 16, Township 7 North, Range 69 West of the 6th P.M. in the City of Fort Collins, Larimer County, Colorado. More specifically, the site is a 20.77-acre property that is currently undeveloped. The site borders Mountaire Subdivision to the east, and to the south, the site borders the back of single-family residential lots facing West Elizabeth Ave. To the west, the site borders the Scenic Views retention pond and the Scenic Views Subdivision. To the north, the site borders single-family residential subdivisions, Locust Grove Filing No. 3, Locust Grove Filing No. 2, and the street Orchard Place. For additional information, refer to the site vicinity map within Appendix A of this report. DESCRIPTION OF PROPERTY The site generally drains west to east at a 2.5% to 1% slope. The site is located in the Canal Importation Basin, specifically north of West Elizabeth Street, east of South Overland Trail, and directly East of the Scenic Views Subdivision. The existing streets Orchard Place and West Plum Street dead end within the site. The Natural Resources Conservation Service (NRCS) soil survey shows that the majority are type C soils, which are characterized by a lower infiltration rate and corresponding higher runoff rates. The remaining soil on site are made up of Type B soils, which are characterized by a moderate infiltration rate and lower runoff rates. For additional information, refer to the NRCS soil map within Appendix A of this report. The existing site is currently used for Agricultural purposes and has an existing house, greenhouse, and field purposed for crops and areas with native grass. The existing irrigation ditch; i.e. the Pleasant Valley and Lake Canal is within the site, it borders the western boundary. The existing groundwater depths and boring locations are shown in Appendix E of this report. The depth from the bottom of the proposed pond to groundwater is approximately 6 feet, as shown in the Polestar Groundwater measurements spreadsheet in Appendix E of this report. MASTER DRAINAGE BASIN DESCRIPTION The site is located in the Canal Importation basin. The 2022 Canal Importation Basin – Selected Plan Update by Jacobs Engineering report specifies that the site is to have a regional detention facility. For additional information on the drainage patterns and characteristics of the site, refer to the Drainage Basins and Sub-Basins section of this report. 2 FLOODPLAIN SUBMITTAL REQUIREMENTS The site is on FEMA FIRM panel 08069C0960F, dated 12/19/2006, as shown in Appendix A. The site lies within FEMA Zone X, areas which are determined to be outside the 0.2% annual chance floodplain. The site is not located within a FEMA regulated floodplain, as shown in Appendix A in the FEMA attachments. The site is located in the City of Fort Collins Canal Importation floodway and floodplain, as shown in Appendix A in the City of Fort Collins Flood map. JR Engineering has prepared a CLOMR for the Polestar site. Once the grading on the site is completed, a LOMR will be submitted to verify the site is in compliance with the CLOMR. No building permits for the residential structures in the existing effective floodway will be issued until the LOMR is approved. The finished floor elevations near the Rain Garden and Scenic Views Pond are currently 1.5 feet above the base floodplain elevation, while the finished floor elevations for the homes and lots adjacent to the Polestar Detention Facility are at least 1.5 feet above the base floodplain elevation. These areas incorporate essential features, including HVAC and electrical equipment, which must all be elevated above the Required Flood Protection Elevation (RFPE). These elevations comply with Chapter 10 of the City Code, ensuring adherence to floodplain regulations such as flood proofing, floodway regulation, erosion buffer zone regulation, and no-rise certification. Additionally, the Conditional Letter of Map Revision (CLOMR) has been submitted, and the floodplain use permit will be submitted prior to the overlot grading, further securing compliance and safety against potential flood events. DRAINAGE BASINS AND SUB-BASINS MAJOR BASINS AND SUB-BASINS The Polestar Village site is 20.78 Acres; the site will be developed into a single-family, multi-family residential community with a community center and other amenities. The site will include future regional onsite and offsite detention. The site is located in the Canal Importation basin. EXISTING SUB-BASIN DESCRIPTION There are offsite areas that flow across the proposed development site. The existing drainage basins within the site flow from west to east. The existing corrected effective basin map is shown in Appendix E of this report. 3 Basin EP 21.5, acres and 3.1% impervious. This basin is composed of native grassland and an existing shed and includes a small portion of residential lots from Locust Grove that drains directly onto the site and drains to a swale towards West Plum Street. EXISTING OFFSITE DRAINAGE BASINS Currently, the site collects offsite runoff at two different locations. The site is currently in the overflow path of the Scenic Views retention pond and receives direct runoff from Locust Grove Filing No. 3; which enters the site via curb and gutter from Locust Grove Drive. The Scenic Views retention facility receives overflow runoff from the Pleasant Valley and Lake Canal, runoff from the Scenic Views multi-family Subdivision, the Colorado State Equine Horse Center, and the Center of Disease Control facility. For additional information, refer to the existing drainage basin SWMM map done in the hydrology portion of the CLOMR in Appendix E of this report. EXISTING OFFSITE DRAINAGE DESCRIPTIONS The offsite flows are currently routed through the site. The existing offsite basins have been modeled in the Canal Importation Basin Selected Plan Update Conceptual Design Report –Plum Channel Flow Path by Jacobs Engineering Group; Dated June, 2022 and within the Canal Importation Basin Hydrologic Conversion from MODSWMM to EPA SWMM 5.1; Anderson Consulting Engineers, Inc., December 6, 2013, (Revised July 3rd 2014). JR Engineering has revised some of the basins in section 5.0 of the CLOMR to account for Polestar site. The basin map for the offsite areas is shown within the corrected effective SWMM drainage map within Appendix E for the revised hydrology update within the CLOMR. Basin 13 is 2.9 acres and 10% impervious. This basin is directly tributary to the privately owned Scenic Views retention facility. The Scenic Views Pond was designed by JR Engineering, LTD to be a temporary retention facility in 1998 as shown in Appendix E of this report. The temporary retention facility has not yet been converted into a detention facility. The retention pond is pumped into the Pleasant Valley and Lake Canal via the existing submersible sumps pump, as shown in Appendix E of this report. The main pump has to be manually started, so the pond was modeled as a complete retention pond with no outflow, just an overflow path within the existing SWMM model. From the 1998 Scenic Views report, the manually operated pump system is designed to evacuate the pond within 24 hours after a large rainstorm event. Since this pond is a retention pond, without a gravity outfall the City does not model any volume below the spillway (the gravity outfall). This offsite basin is shown in the existing SWMM map shown within Appendix E of this report. 4 17W is 10.2 Acres and 45% impervious. This offsite basin is shown in the existing SWMM map, as shown within Appendix F of this report. For SWMM master planning purposes, Anderson used 45% impervious for single-family detached residential homes. This basin drains from Locust Grove Drive onto the Polestar site. Basin 10, 64.4 Acres, and 20% impervious. This basin is tributary to the Colorado State University Equine Reproduction Laboratory, located west of the site directly west of South Overland Trail. Runoff from this basin is released from the Equine Center pond and is then piped to the Scenic Views pond. This offsite basin is shown in the existing SWMM map shown within Appendix F of this report. Basin 11, 23.1 Acres and 70% impervious. This basin is tributary to the Scenic View’s subdivision. Runoff from this basin is detained in the Scenic Views pond. This offsite basin is shown in the existing SWMM map shown within Appendix E of this report. PROPOSED SUB-BASINS DESCRIPTIONS To model the proposed runoff going into the on-site detention facility the pond was modeled as a composite 21.5-acre basin in SWMM a with 50% impervious value. The Polestar SWMM model was slightly more conservative than the basin area and impervious values to account for potential site changes and design variations through the CLOMR process, and the basin was delineated over a small portion of the Locust Grove subdivision that accounts for additional area. The proposed net area of the site is 20.77 acres at 47.5% impervious. The following is a description of the individual sub-basins for the onsite composite basin. The drainage sub-basin basins have been broken up and delineated, the onsite runoff is being routed with the rational method. The proposed site and pond drainage was modeled in a composite basin within SWMM, as part of the revised hydrology section of the CLOMR. Basin A1, 1.02 acres and 15.8% impervious this basin is composed of open space a proposed walk, a rain garden, and an overflow structure that treats runoff and water quality from the Polestar Village site. Basin A2, 0.58 acres and 51.6% impervious this basin is composed of multi-family residential units, a 24’ wide private alley - Hoku Lane, and onsite parking. The runoff from this basin will be conveyed via a paned alley to the curb and gutter on West Plum Street. 5 Basin A3, 0.78 acres and 25.3% impervious this basin is composed of multi-family residential units, duplex units, a private walk and a swale. The runoff from this basin will be conveyed via a swale and chase to West Plum Street at dp 3a. Basin A4, 1.23 acres and 65.0% impervious this basin is composed of multi-family residential units, paved walk and paved driveways, paved parking spaces, a portion of the mitigated wetland and a 24’ wide private alley Ohana Circle . The runoff from this basin goes to design point 4a and drains to W. Plum Street. Basin A5, 0.42 acres and 56.5% impervious this basin is composed of a courtyard, paved walks, duplex and multi-family units. The runoff drains to multiple area inlets. The runoff is then piped within the proposed storm sewer system in West Plum Street. Basin A6, 1.03 acres and 56.5% impervious this basin is composed of a local street West Plum Street, paved walk and front-facing multi-family units. The runoff from this basin goes to a sump inlet at design point 6a. Basin A7, 0.85 acres and 60.5% impervious this basin is composed of a local Street West Plum, paved walk. The runoff from this basin goes to a sump inlet at design point 7a. Basin A8, 0.58 acres and 83.8% impervious, composed of the mixed-used community building, the northern portion of the temple, community, bed and breakfast building, the wellness center, a duplex, multi-family units, pedestrian walks, and a 24' wide private alley Ohana Circle. Runoff from this basin drains to W. Plum Street at dp 5d. Basin A9.1, 0.16 acres and 84.4% impervious, this basin is composed of the mixed used community building and a multi-family unit. Runoff from this basin will be captured via a series of on-grade inlets at dp 9a and piped to the proposed storm sewer in W. Plum St. Basin A9.2, 0.03 acres and 54.5% impervious, this basin is composed of open space, pedestrian walks and parts of the multi-family units drain to this basin. This basin drains to an area inlet at dp 9.2a, where runoff is then piped to the storm sewer in W. Plum St. 6 Basin A10, 0.09 acres and 84.7% impervious, is composed of the eastern portion of the temple, community, bed and breakfast building. Runoff from this building will drain into an area inlet at dp 10a, where it will then be piped to the proposed storm sewer system in W. Plum St. Basin A11, 0.13 acres and 68.8% impervious, this basin is composed of pedestrian walks, a portion of a multi-family unit, a gazebo. Runoff from this basin makes its way to an area inlet at dp 11a, where it is then piped to the proposed storm sewer system in W. Plum St. Basin A12, 0.26 acres and 33.7% impervious this basin is composed of pedestrian walks a portion of the onsite playground and picnic area. Runoff from this basin makes its way to an area inlet where it is then piped to the proposed storm sewer system in W. Plum St. Basin A13, 0.40 acres and 61.0% impervious, this basin is made up a portion of the eastern half of the group home/ wellness center and the western portion of the temple, community, bed and breakfast building. Basin A15, 0.49 acres and 23.5% impervious, this basin is made up of pedestrian walks and a portion of the mitigated wetland. Runoff from this basin overtops the wetland and drains to an area inlet a dp 15a, where it is then piped to the proposed storm sewer system in W. Plum St. Basin A16, 0.13 acres and 51.1% impervious, this basin is made up of pedestrian walks, the pickle ball court, and drains to an area inlet at dp 16a. The runoff is then piped to the proposed storm sewer system in W. Plum St. Basin A17, 0.43 acres and 29.6% impervious, is made up of pedestrian walks, the community garden, and multi-family units. Runoff from this basin drains to a series of on-grade area inlets at dp 17a. The runoff from this basin is then piped to the proposed storm sewer system in W. Plum Street. Basin A18, 0.72 acres and 45.8% impervious, is made up of pedestrian walks, the community garden, the agriculture building, and multi-family units. Runoff from this basin is pipe via a series of on-grade inlets and a pipe with a trench drain at dp 18a due to the shallow slope of the swale. The runoff from this basin is then piped to the proposed storm system within W. Plum St. 7 Basin A19, 0.35 acres and 51.5% impervious is made up of pedestrian walks, the agriculture building, and a portion of the pickleball court. Runoff from this basin drains to a series of on-grade area inlets at dp 19a where it is then piped to the proposed storm sewer system in W. Plum St, Basin B1, 1.23 acres and 49.8% impervious, is made up of pedestrian walks, multi-family units, duplex units, a rain garden, and a 24’ wide private alley - Mele Lane. Runoff of from this basin drains via a chase drain to a rain garden where it is treated for water quality. This the runoff from this basin goes to the onsite Polestar detention pond. Basin B2, 0.31 acres and 77.7% impervious, is made up of pedestrian walks, multi-family units, and a 24’ wide private alley - Koku Lane. Runoff of from this basin drains via a chase drain to a rain garden where it is treated for water quality. This the runoff from this basin goes to the onsite Polestar detention Pond. Basin C1, 0.28 acres and 47.0% impervious this basin is composed of residential multi family units, paved walk, and a rain-garden. The runoff from this basin drains into a rain garden, where it is then released into the Polestar detention facility. Basin C2, 0.32 acres, and 30.5% impervious this basin is composed of paved walk, grass and the multi- family units. The runoff from this basin drains into an area inlet a design point 2C. Basin D1, 0.35 acres and 64.1% impervious this basin is composed a 24’ wide paved private alley – Happy Heart Way, a duplex unit and paved walk. The runoff from this basin drains via the alley to a curb cut at 2d where it confluences with the runoff from Basin D2 and is treated for water quality. Basin D2, 0.22 acres and 62.9% impervious basin, is composed of a 24' wide paved private alley – Happy Heart Way, a duplex unit, and a paved walk. The runoff from this basin drains via the alley to a curb cut at 2d. Basin D3, 0.16 acres and 69.8% impervious this basin is this basin is composed a 24’ wide paved private alley – Happy Heart Way, a duplex unit and paved walk. The runoff from this basin drains via the alley to a curb cut at 3d. From then the runoff is treated for water quality in a rain garden where it is then piped to the Polestar detention facility. 8 Basin D4, 0.25 acres and 60.9% impervious this basin is this basin is composed a 24’ wide paved private alley – Happy Heart Way, a duplex unit and paved walk. The runoff from this basin drains via the alley to a curb cut at 4d. From then the runoff is treated for water quality in a rain garden where it is then piped to the Polestar detention facility. Basin D5, 0.29 acres and 67.3% impervious this basin is this basin is composed W. Plum Street, pedestrian walks and a portion of some multi-family units. The runoff from this basin drains to the rain garden via a chase a 5d. From then the runoff is treated for water quality in a rain garden where it is then piped to the Polestar detention facility. Basin D6, 0.28 acres and 60.5% impervious this basin is this basin is composed W. Plum Street. Runoff from this basin drain to a rain garden via a modified 5’ type R inlet at dp 6d. From there on the runoff is then piped to the onsite Polestar detention pond. Basin D7, 0.11 acres and 85.5% impervious this basin is this basin is composed of a 24’ wide private alley - Pono Way, and a duplex unit. Runoff from this basin drain to a rain garden via a curb cut at dp 7d. From there on the runoff is then treated within a rain garden and then it is pipe to the onsite Polestar detention pond. Basin D8, 0.18 acres, and 90.5% impervious this basin is composed of a 24’ wide private – Pono Way, and pedestrian walks. Runoff from this basins drains via a curb cut at dp 8d. Basin E1 is 2.24 acres and 41.1% impervious. This basin consists of West Orchard Place and single-family residential units. The runoff from this basin will drain via a mid-block pan at dp 1e. Basin E2, 0.54 acres and 54.2% impervious this basin consists of a local residential road West Orchard Place, single family units and drains via curb and gutter to an on grade a mid block pan at dp 2e. Basin E3, 0.31 acres and 59.0% impervious this basin consists of a local residential road West Orchard Place, single family units and drains via curb and gutter to an on grade inlet a design point 3e. Basin F1, which is 3.9 acres and 31.6% impervious, is composed of the onsite detention facility. 9 OS1, 0.61 acres and 15.2% impervious this basin drains onto West Orchard Place, this basin is part of the back of lots of the Locust Grove subdivision. The runoff from this basin drains in the mid-block pan in West Orchard St and is released into the interim detention facility. OS2, 0.09 acres and 50.8% impervious, part of the Locust Grove Subdivision, this basin drains onto West Orchard Place and drains into the detention facility. PROJECT DESCRIPTION PROJECT DESCRIPTION Polestar Village is a residential multi-family development that will consist of a community center, wellness center, alleys, and local and collector roadways. The Polestar Village site will hold regional detention and water quality for the site. In the future, after the site is fully developed, the Canal Importation basin offsite improvements will be built with additional volume from the Jacobs Canal Importation basin Selected Plan updated June 2022. JR Engineering has designated approximately 3 acres of the site for regional detention. The proposed and future detention facility volume requirements were done by modeling the site in EPA SWMM as part of the revised hydrology portion of the CLOMR, as shown within Appendix E. The future onsite regional detention facility is shown in Appendix F of this report. PROPOSED DRAINAGE FACILITIES GENERAL CONCEPT The proposed improvements to the Polestar Village site will result in the developed condition being treated and detained for water quality. Low-impact development best management practices are proposed to improve the quality of runoff and aid in reducing peak flows. Specifically, rain gardens are proposed near the central portion of the site to treat and provide water quality for the majority of the development. Runoff from the site is captured in inlets located in the alleys and grate inlet along the curb and gutter. Runoff is conveyed in storm sewers, along curb and gutter, and via surface flow to rain gardens. Secondly, surface overflow paths will be provided, such that the 100-year storm flows remain at least 1.0 to 1.5 feet below the finished floor elevation. WATER QUALITY/ DETENTION FACILITIES The majority of the water quality is treated within the onsite rain gardens. The remaining water quality within the site will be treated in the water quality and detention facility. A small portion of the site of a 10 type A lot, will be left untreated due to the lot draining to the existing West Orchard R.O.W and pavement adjacent to the lot frontage. Additionally, a portion of the berm and access road to the detention pond will drain off-site and into the Plum Channel drainage way. This is not anticipated to have any negative impact on downstream drainage infrastructure, and the total water quality is being treated for 99% of the Polestar site’s modified impervious area. For additional information, the LID water quality treatment exhibit is shown in Appendix G of this report. LOW IMPACT DEVELOPMENT A minimum of 75 percent of new impervious surface area is treated by a Low-Impact Development (LID) best management practice (BMP) in accordance with City criteria. An illustrative LID/ Surface Map is provided in Appendix G, and the sizing of the LID methods is provided in Appendix D. DRAINAGE DESIGN CRITERIA REGULATIONS This report was prepared to meet or exceed the City of Fort Collins stormwater criteria. The City of Fort Collins Stormwater Criteria Manual (dated 2018)(FCSCM) and the Urban Drainage Flood Control District’s (UDFCD) Drainage Criteria Manual (USDCM) Volumes 1, 2 and 3 were referenced as guidelines for this design. FOUR STEP PROCESS TO PROTECT RECEIVING WATERS The City of Fort Collins requires the Four Step Process to protect receiving waters. The four-step process incorporates reducing runoff volume, treating water quality capture volume, stabilizing streams, and implementing long-term source controls. Volume reduction is an important part of the Four Step Process and is fundamental to effective stormwater management. Per City Criteria, a minimum of 75 percent of new impervious surface area must be treated by a Low-Impact Development (LID) best management practice (BMP). The site incorporates rain gardens to provide water quality. The rain gardens will need to be cleaned and maintained to allow for long-term protection of the receiving waters. The proposed LID BMPs will have the effect of slowing runoff through the site lot and increasing infiltration and rainfall interception by encouraging infiltration and careful selection of vegetative cover. The improvements will decrease the runoff coefficient from the site and are expected to have no adverse impact on the timing, quantity, or quality of stormwater runoff. Overall, water quality will be improved by the development. The majority of the new impervious area is treated by the proposed raingarden in the northwestern 11 portion of the site as illustrated in the LID/Surface Map is provided in Appendix G. Refer to Appendix G for additional information on water quality treatment methods throughout the site. Step 1 – Employ Runoff Reduction Practices All of the developed runoff through the site will be routed through the onsite interim Polestar detention pond. Step 2 – Implement BMPS that Provide a Water Quality Capture Volume The Polestar site BMP treatment methods include bioretention basins (rain gardens), and WQCV provided within the interim Polestar detention pond. Step 3 –Stabilize Drainageways The Interim Polestar detention facility provides flood control for the site. The runoff leaving the site will be channelized via a swale with a reinforced wall and a concrete pan with an energy dissipation forebay. In addition, a headwall is being built for the existing twin 24” RCP conduits to provide further stabilization to the existing drainage way. Step 4 – Implement site-specific and other source-control BMPs To further enhance the stormwater management practices at the Polestar site, a dog waste station will be installed near the detention pond. This station will include waste bags and a disposal waste station, encouraging pet owners to clean up after their pets. DEVELOPMENT CRITERIA REFERENCE AND CONSTRAINTS The site is part of the Canal Importation - Basin Selected Plan Updates Alternatives Analysis Report, by Jacobs Engineering Group and is currently in the process of conceptual design. The site was previously analyzed in the Canal Importation Basin Hydrologic Conversion from MODSWMM to EPA SWMM 5.1; Anderson Consulting Engineers, Inc, December 6, 2013, (Revised July 3rd 2014). Jacobs Engineering group is currently modifying the Anderson model for the City of Fort Collins Capital Improvement plan for the Canal Importation basin. JR Engineering has evaluated the floodplain for the site, and JR Engineering has prepared a CLOMR to show that the improvements to the site are not within the floodplain. The CLOMR shows to the newly mapped floodway and floodplain, ultimately a LOMR will need to be approved to ensure the site complies with the CLOMR. The improvements for the planned regional Happy Hearts detention facility will take place in the future after the site is developed into Polestar Village. The Polestar Community will not impact the downstream development, and onsite detention will be provided within the site, but the homes downstream of the site will remain within the floodplain until the improvements 12 to the offsite and onsite facilities are put in place as recommended in the Canal Importation - Basin Selected Plan Updates, by Jacobs. The following items are a list of the subject improvements. Conversion of Scenic Views retention pond to a detention pond. Addition of a pipe outfall from the Scenic Views detention pond to the Happy Heart Farms, i.e., Polestar detention pond. The volume of the onsite detention pond should be increased per the proposed outfall. Construction of the planned outfall from the regional detention facility Currently, in the 100-year event, the Pleasant Valley and Lake Canal overflows and spills into the Scenic Views pond. The Scenic Views pond has a manually operated pumped outfall to the Pleasant Valley and Lake Canal. In the 100-year event, water overtops the Scenic Views pond and goes on the Polestar site, creating a floodplain as shown in the existing drainage map within Appendix F. In the proposed condition, the floodplain will go onto the onsite rain garden, overtop W. Plum Street and then the floodplain will be contained within the proposed detention facility. However, due to the shallow gravity outfall and limited volume the ultimate detention facility, as shown in Appendix E. - cannot be built due to the lack of a deep gravity outfall. The interim condition provides a drainage easement, an energy dissipation structure, and a concrete pan and will convey runoff, as shown in the Drainage Map in Appendix F. The onsite detention requirement for the site is the runoff difference between the 100-year developed inflow rate and the 2-year historic runoff is 4.88 Acre-ft. For additional information on the detention pond volume calculation, please refer to the referenced CLOMR provided hydrology portion provided in Appendix E. Jacobs calculated the ultimate volume (Happy Heart Detention Pond) within the Canal Importation - Basin Selected Plan Updates dated June 2022 as 8.3 Acre-ft. The total ultimate detention volume was calculated by adding the Happy Heart Detention pond of volume 8.3 Acre-ft with the required interim (onsite) detention volume 4.88 Acre-ft for the Polestar site for a total volume of 13.18 Acre-ft. JR Engineering has verified that the proposed pond layout can be graded in the future to detain over 13.18 Acre-ft as shown in the Future regional detention map provided in Appendix F. JR Engineering has prepared three SWMM models for the Polestar site within the City of Fort Collins Canal Importation Basin: the Corrected Effective Model, the Proposed Model, and the Ultimate Model. 13 The City of Fort Collins has requested that JR Engineering incorporate the Polestar Drainage model into the City master Canal Importation Drainage Plan SWMM mode. This was completed within the revised hydrology portion of the CLOMR, as shown within Appendix E. The groundwater for the site is greater than two feet below the Polestar detention pond invert, as noted in the CTL groundwater exhibit in Appendix E. HYDROLOGIC CRITERIA Weighted percent imperviousness were calculated for each basin using the Fort Collins Stormwater Criteria Manual Table 3.2-2 for each basin. EPA SWMM was used to model the runoff for the site and size the Polestar detention facility since the corresponding tributary area of the site is over 20 acres, and there are multiple detention basins upstream of the site that are in series with one another. The City of Fort Collins area has rainfall depths associated with the table below, as shown in Chapter 5 of the Fort Collins Stormwater Criteria Manual (FCSCM). 14 The rational method was used to size the onsite storm sewer drainage facilities. Runoff coefficients from the FCSCM Table 3.2-1. Zoning Classification - Runoff Coefficients and Table 3.2-2. Surface Type - Runoff Coefficients were utilized to calculate the composite C values. Rainfall intensities for the 2 year minor storm and 100 year major storm were taken from table 3.4-1. IDF Table for Rational Method. HYDRAULIC CRITERIA StormCAD was utilized to determine the hydraulic capacity of the storm sewer system on site. Headloss coefficients were input as recommended by AMEC. "Modeling Hydraulic and Energy Sewer Gradients in Storm Sewers: A Comparison of Computational Methods." UDFCD, 6 Oct. 2009. The stormCAD V8i input/results are shown in Appendix C.A tailwater condition was used in the stormCAD model. The tailwater entered into the StormCAD model for the storm outfalls corresponds to the peak inflow within the pond for the 100-year event. This occurs 40 minutes into the model, and the depth of the pond is at 5105.98. No tail water was used for the 2-year model. For rain garden number 1, the water WQCV depth was used as the tailwater condition in the 100-year event. This corresponds to an elevation of 5107.35. For the outfall, a 100-year tailwater condition of 5106.23 was used to model the outfall into the floodplain located within the energy dissipation forebay. 5106.23 is the water surface elevation in the CLOMR at section 4673.7 – which is within in the energy dissipation directly downstream of the pipe. There is a mid-block pan that bi-sects West Orchard Place, that accepts runoff from Locust Grove. Runoff from the midblock pan drains into a swale in the 100 year event drains directly into the Polestar detention facility. The hydraulics of the mid-block plan and the swale were modeled within Flow Master as shown in Appendix C of this report. The 100-year spillway from the Scenic Views Pond and the Polestar Pond were sized during the CLOMR process in Flow Master. For additional information on the Spillway sizing, refer to the attached variance letter for the CLOMR in Appendix E of this Report. The inlets for the site were sized using parameters from the Fort Collins Stormwater Criteria Manual (FCSCM). The UD Inlet MHFD-Inlet, Version 5.03 (August, 2023) spreadsheet was utilized for the design and sizing of these inlets, as shown in Appendix C of this Report. 15 FLOODPLAIN REGULATIONS COMPLIANCE As previously stated, the site lies within FEMA Zone X, areas which are determined to be outside the 0.2% annual chance floodplain. The site is not located within a FEMA-regulated floodplain, as shown in Appendix A in the FEMA attachments. The site is located in the City of Fort Collins Floodplain and there is a floodway within the site, as shown in Appendix A in the City of Fort Collins Flood map. All development is within in compliance with Chapter 10 of the City of Fort Collins Code. MODIFICATIONS OF CRITERIA JR Engineering is proposing modifications for the spillway in Scenic Views Pond to increase emergency overflow capacity, decrease the overall breadth of the floodplain, and reduce the emergency overflow depth from 1.9 ft to 1.75 ft, as shown in the attached variance letter from the CLOMR in Appendix E. The proposed improvement will stop the spillway from overflowing by making it longer. In addition, the new proposed configuration will provide 6" of freeboard for the Scenic Views Spillway. The proposed Polestar/Happy Heart Farms Spillway is intended to prevent the flow from the emergency spillway from being directed towards existing structures and homes downstream. Both proposed spillways exceed the required depth of six inches, but the variance is necessary to achieve the desired outcomes. For additional information, refer to Appendix E for the variance letter, which was done with the CLOMR. The site will be broken up into five phases. For large-scale, multi-phase developments, the City of Fort Collins wants each phase to meet the 75% proposed LID treatment method. However, this requirement is not met until all phases of the development are complete. Instead of treating 75% of the site's impervious area in Phase 1, when the detention pond is constructed, the pond has been designed to treat offsite water quality from a portion of Locust Grove to the north. Currently, runoff from Locust Grove is left untreated. For additional information, the variance letter has been attached in Appendix E of this report. EROSION CONTROL The Polestar Utility Plans are in compliance with the Erosion Control Criteria established by the City of Fort Collins. The erosion control measures have been designed to minimize soil erosion and sediment transport off-site, ensuring compliance with local, state, and federal water quality regulations. All control measures will be maintained and inspected regularly to ensure their effectiveness throughout the construction process until final stabilization is achieved. All Erosion Control Materials and measures detailed in the Utility Plans adhere to the standards and specifications set forth by the City of Fort Collins within the Stormwater Criteria Manual. Erosion Control Plans, as referenced in the Polestar Utility Plans, 16 are living documents that can be subject to change under the direction of the Engineer of Record and/or the City of Fort Collins Engineering Department. CONCLUSIONS COMPLIANCE WITH STANDARDS The hydrologic and water quality calculations were performed using the required methods as outlined in the City of Fort Collins Stormwater Criteria Manual. The drainage plan and Stormwater management measures proposed within the Polestar site are complaint with all applicable State and Federal regulations governing Stormwater discharge. The drainage design conforms to the Jacobs' Master Canal Importation Basin plan by providing an area designed for detention in the ultimate gravity pond outfall configuration. The site conforms to the revised Hydrology of documented Polestar Floodplain Modeling Report by JR Engineering dated November of 2024. The floodplain compliance requirements for the site have been detailed in the CLOMR (Conditional Letter of Map Revision) for various parameters, including elevation, flood proofing, critical facilities, tie-in of upstream and downstream WSEL (Water Surface Elevation), and structures. DRAINAGE CONCEPT The proposed concept for the Polestar Village Development involves surface flows and piping of developed conditions and offsite flow through the interim detention facility. The site includes LID water quality facilities with rain gardens. Runoff for the site will be treated in an interim detention facility onsite. The proposed development will affect the drainageway termed “Plum Street Flow Path” which is located in the northwestern portion of the Canal Importation Basin. Onsite detention is provided for the Polestar site, but the homes downstream of the site will remain with the floodplain until the improvements to the offsite and onsite facilities are put in place as recommended in the Canal importation – Basin Selected Plan Updates Analysis Report, by Jacobs dated June 2022. 17 REFERENCES Fort Collins Stormwater Criteria Manual; City of Fort Collins, Colorado, December 2018. Urban Storm Drainage Criteria Manual (Volumes 1, 2, and 3); Urban Drainage and Flood Control District, June 2001. Canal Importation Basin Hydrologic Conversion from MODSWMM to EPA SWMM 5.1; Anderson Consulting Engineers, Inc, December 6, 2013, (Revised July 3rd 2014) Canal Importation basin Selected Plan Update, Jacobs Engineering Group,Dated June 2023 Preliminary Geotechnical Investigation Polestar Village; CTL Thompson, Dated November 2021 Floodplain Modeling Report for Polestar Village; JR Engineering, Dated November 2024 18 APPENDIX A – FIGURES A Westrian Company Hydrologic Soil Group—Larimer County Area, Colorado Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 5/17/2022 Page 1 of 4 44 9 1 4 0 0 44 9 1 5 0 0 44 9 1 6 0 0 44 9 1 7 0 0 44 9 1 8 0 0 44 9 1 9 0 0 44 9 2 0 0 0 44 9 2 1 0 0 44 9 2 2 0 0 44 9 2 3 0 0 44 9 2 4 0 0 44 9 1 4 0 0 44 9 1 5 0 0 44 9 1 6 0 0 44 9 1 7 0 0 44 9 1 8 0 0 44 9 1 9 0 0 44 9 2 0 0 0 44 9 2 1 0 0 44 9 2 2 0 0 44 9 2 3 0 0 44 9 2 4 0 0 488700 488800 488900 489000 489100 489200 489300 489400 488700 488800 488900 489000 489100 489200 489300 489400 40° 34' 59'' N 10 5 ° 8 ' 2 ' ' W 40° 34' 59'' N 10 5 ° 7 ' 2 7 ' ' W 40° 34' 23'' N 10 5 ° 8 ' 2 ' ' W 40° 34' 23'' N 10 5 ° 7 ' 2 7 ' ' W N Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 13N WGS84 0 250 500 1000 1500 Feet 0 50 100 200 300 Meters Map Scale: 1:5,390 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 16, Sep 2, 2021 Soil map units are labeled (as space allows) for map scales 1:50,000 or larger. Date(s) aerial images were photographed: Aug 11, 2018—Aug 12, 2018 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 5/17/2022 Page 2 of 4 Hydrologic Soil Group Map unit symbol Map unit name Rating Acres in AOI Percent of AOI 3 Altvan-Satanta loams, 0 to 3 percent slopes B 68.4 43.1% 4 Altvan-Satanta loams, 3 to 9 percent slopes B 38.2 24.1% 37 Fort Collins loam, 5 to 9 percent slopes C 0.0 0.0% 48 Heldt clay loam, 0 to 3 percent slopes C 9.2 5.8% 64 Loveland clay loam, 0 to 1 percent slopes C 15.9 10.0% 74 Nunn clay loam, 1 to 3 percent slopes C 2.2 1.4% 76 Nunn clay loam, wet, 1 to 3 percent slopes C 11.8 7.5% 95 Satanta loam, 1 to 3 percent slopes C 12.9 8.1% Totals for Area of Interest 158.5 100.0% Hydrologic Soil Group—Larimer County Area, Colorado Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 5/17/2022 Page 3 of 4 Description Hydrologic soil groups are based on estimates of runoff potential. Soils are assigned to one of four groups according to the rate of water infiltration when the soils are not protected by vegetation, are thoroughly wet, and receive precipitation from long-duration storms. The soils in the United States are assigned to four groups (A, B, C, and D) and three dual classes (A/D, B/D, and C/D). The groups are defined as follows: Group A. Soils having a high infiltration rate (low runoff potential) when thoroughly wet. These consist mainly of deep, well drained to excessively drained sands or gravelly sands. These soils have a high rate of water transmission. Group B. Soils having a moderate infiltration rate when thoroughly wet. These consist chiefly of moderately deep or deep, moderately well drained or well drained soils that have moderately fine texture to moderately coarse texture. These soils have a moderate rate of water transmission. Group C. Soils having a slow infiltration rate when thoroughly wet. These consist chiefly of soils having a layer that impedes the downward movement of water or soils of moderately fine texture or fine texture. These soils have a slow rate of water transmission. Group D. Soils having a very slow infiltration rate (high runoff potential) when thoroughly wet. These consist chiefly of clays that have a high shrink-swell potential, soils that have a high water table, soils that have a claypan or clay layer at or near the surface, and soils that are shallow over nearly impervious material. These soils have a very slow rate of water transmission. If a soil is assigned to a dual hydrologic group (A/D, B/D, or C/D), the first letter is for drained areas and the second is for undrained areas. Only the soils that in their natural condition are in group D are assigned to dual classes. Rating Options Aggregation Method: Dominant Condition Component Percent Cutoff: None Specified Tie-break Rule: Higher Hydrologic Soil Group—Larimer County Area, Colorado Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 5/17/2022 Page 4 of 4 ROCKY RD W ELIZABETH ST KIMBALL RD ORCHARD PL W PLUM ST ARANCIA DR LOUISE LN TIERRA LN CUERTO LN RADCLIFF CIR Printed: 07/14/2021. All floodplain boundaries are approximate. This information is based on the Federal Emergency Management Agency (FEMA) Flood Insurance Rate Map (FIRM) and the City of Fort Collins Master Drainageway Plans. This letter does not imply that the referenced property will or will not be free from flooding or damage. A property not in the Special Flood Hazard Area or in a City Designated Floodplain may be damaged by a flood greater than that predicted on the map or from a local drainage problem not shown on the map. This map does not create liability on the part of the City, or any officer or employee thereof, for any damage that results from reliance on this information. City Flood Risk Map Moderate Risk May include:- Areas of FEMA 500-year floodplain (FEMA Zone X-shaded).- Areas of FEMA or City 100-year floodplain (sheet flow) with average depths of less than 1 foot.- Areas protected by levees from the 100-year flood.Low Risk Areas outside of FEMA and City mapped 100-year and 500-year floodplains. Local drainage problems may still exist. City Flood Fringe - May Include:- Areas of FEMA 100-year floodplain (FEMA Zones A, AE, AO, and AH)- Areas of City 100-year floodplain including ponding areas and sheet flow areas with average depths of 1-3 feet.There is a 1% annual chance that these areas will be flooded. High Risk City Floodway - Area of 100-year floodplain with greatest depths and fastest velocities. 0 140 280 420 56070Feet Fort Collins Utilities Floodplain Administration (970) 416-2632 Page 1 of 7 City of Fort Collins Floodplain Review Checklist Development Review Submittals Instructions: Complete this checklist by marking all boxes that have been adequately completed. Put an “NA” next to any items that are not applicable to this particular submittal. Any boxes that are left blank and do not have an “NA” marked next to them are considered incomplete. Date of Review: Reviewer’s Name: Plat Map The following required items are on the plat: ☐ 100-year floodplain boundary ☐ City ☐ FEMA ☐ Floodway boundary ☐ City ☐ FEMA ☐ These items match the FIRM. (FEMA Basin) ☐ These items match the Master Plan. (City Basin) Site Plan The following required items are on the site plan: ☐ 100-year floodplain boundary- FEMA and City ☐ 500-year floodplain boundary (if proposed structure is a “critical facility” and a 500-year floodplain is mapped) ☐ Floodway boundary ☐ Erosion buffer zones ☐ Restrictions related to use (ie. critical facility or no residential use of lower floor if floodproofed mixed use structure) Drainage and/or Grading Plan (or a separate Floodplain Sheet if it is too cluttered on Drainage and Grading Plan) The following required items are on the drainage and/or grading plan: ☐ 100-year floodplain boundary- FEMA and City ☐ 500-year floodplain boundary (if proposed structure is a “critical facility” and a 500-year floodplain is mapped) ☐ Floodway boundary Fort Collins Utilities Floodplain Administration (970) 416-2632 Page 2 of 7 ☐ Erosion buffer zones ☐ Cross-section locations ☐ BFE lines ☐ Lowest floor elevation of structures (bottom of basement or crawl space is considered the lowest floor) ☐ The floodplain and floodway boundaries are in the correct location and labeled properly. ☐ The cross-section and BFE lines are in the correct location and labeled properly. ☐ Elevations are referenced to the 1988 datum: ☐ Floodway regulations have been met. ☐ No fill in the floodway unless a hydraulic analysis shows “no-rise”. ☐ No manufactured homes, except in an existing park, can be placed in the floodway. ☐ No changing a nonconforming non-residential or mixed use structure to a residential structure. ☐ Landscaping meets requirements for no encroachment in the floodway without a hydraulic analysis to show “no-rise”. ☐ No storage of materials or equipment. ☐ A note is on the plans about the above floodway restrictions. ☐ Critical facilities regulations have been met: ☐ 100-year –no at-risk population, essential service, government service or hazardous material critical facilities ☐ 500-year Poudre –no at-risk population or essential service, critical facilities ☐ Any pedestrian bridges in the floodway that are not able to pass the 100-year flow are designed to be “break-away”. ☐ Fences in the floodway will not block conveyance. Example: split-rail fence cabled together to not float, flap at bottom of privacy fence to allow water through (flap at BFE or above). ☐ Any items in the floodway that can float (Example: picnic tables, bike racks, etc.) are noted as being anchored. ☐ Erosion Buffer Zone requirements have been met: ☐ Design of any allowed development minimizes disturbance to channel bed and banks. Fort Collins Utilities Floodplain Administration (970) 416-2632 Page 3 of 7 ☐ No structures allowed. ☐ No additions to existing structures allowed. ☐ Any fencing is split-rail design and break-away, but cabled. Must be oriented parallel to general flow direction. ☐ No detention or water quality ponds. ☐ No bike or pedestrian paths or trails except as required to cross streams or waterways. ☐ Road, bicycle and pedestrian bridges must span erosion buffer zone. ☐ No fill. ☐ No outdoor storage of non-residential materials or equipment. ☐ No driveways or parking areas. ☐ No irrigated vegetation and non-native trees, grasses, or shrubs. ☐ No utilities except as necessary to cross streams or waterways. ☐ No grading or excavation except as required for permitted activities in erosion buffer zone. ☐ No construction traffic except as required for permitted activities in erosion buffer zone. ☐ Any construction in the erosion buffer zone shows that it will not impact the channel stability. ☐ A note is on the plans about the above erosion buffer zone restrictions. ☐ Any necessary floodplain modeling has been submitted and approved. All modeling must follow the City’s floodplain modeling guidelines. Special Poudre River Regulations ☐ Poudre River Floodway Regulations have been met. ☐ No construction of new residential, non-residential or mixed- use structures. ☐ No redevelopment of residential, non-residential or mixed-use structures. ☐ No additions to residential, non-residential or mixed-use structures. ☐ No fill unless hydraulic analysis shows “no-rise”. ☐ Poudre River floodplain regulations have been met ☐ No construction of new residential or mixed-use structures ☐ No additions to residential structures ☐ No additions to mixed-use structures if there is an expansion in the residential-use area of the structure. ☐ No floatable materials on non-residential sites ☐ Emergency Response and Preparedness Plan (ERPP) draft has been prepared. Fort Collins Utilities Floodplain Administration (970) 416-2632 Page 4 of 7 Information Related to Structures in the Floodplain ☐ For structures in the floodplain, a table is shown that lists the following: ☐ City BFE at upstream end of structure ☐ FEMA BFE at upstream end of structure (if different than City BFE) ☐ Regulatory flood protection elevation ☐ Lowest floor elevation (bottom of basement or crawl space is considered lowest floor) ☐ Floodproofing elevation for non-residential structures (if applicable) ☐ Garage slab elevation ☐ HVAC elevation ☐ The BFE at upstream end of structures are correct based on interpolation between the cross-sections. ☐ The regulatory flood protection elevation is correct. ☐ The lowest floor and HVAC are at or above the regulatory flood protection elevation. ☐ Elevations are referenced to the 1988 datum. ☐ A typical drawing detail is included for each foundation type proposed (slab-on- grade, basement, crawl space) showing the elevation of the HVAC and lowest floor elevation (which includes bottom of the basement or crawl space) relative to the BFE. ☐ If garage is not elevated to the regulatory flood protection elevation, then a drawing detail is included showing vent placement, size, and number. ☐ There is 1 square inch of venting for every 1 square foot of enclosed area. ☐ The bottom of the venting is not higher than 1 foot above grade. ☐ The venting is on at least two sides, preferably on upstream and downstream sides. (Does not have to be divided equally). ☐ If a non-residential structure is to be floodproofed, one of these conditions is met: ☐ All requirements on separate sheet titled “Floodproofing Guidelines” have been met. ☐ If floodproofing information is not submitted as part of the plans, then a note is on the plans stating that floodproofing information will be submitted at the time of the building permit application. ☐ For manufactured homes, all submittal requirements on separate sheet titled “Installation of a Mobile Home Located in a Floodplain: Submittal Requirements” have been met. Fort Collins Utilities Floodplain Administration (970) 416-2632 Page 5 of 7 ☐ If the floodplain use permit is not going to be submitted until the building permit is applied for, then a note is on the plans stating that the floodplain use permit will be submitted at the time of building permit application. ☐ A note is on the plans stating that a FEMA elevation or floodproofing certificate will be completed and approved before the CO is issued. This is required even if property is only in a City floodplain. Drainage Report ☐ The site is described as being in the floodplain. Floodplain name and if the floodplain is a FEMA or City-designated is described. Any floodway or erosion buffer zones on the site are described. ☐ The FEMA FIRM panel # and date and/or the Master Plan information is cited. ☐ A copy of the FIRM panel with the site location marked is included in the report. ☐ If a floodplain modeling report has been submitted, that report is referenced. The reason for the floodplain modeling report is described. ☐ If a FEMA CLOMR or LOMR has been approved for the site, the case number is referenced. The reason for the CLOMR or LOMR is described. ☐ If a FEMA LOMR is required after construction, this is stated in the report. ☐ The location of the structures relative to the floodplain is described. If there is both a FEMA and a City floodplain on the site, the location of the structures relative to both is described. ☐ The use of the structures is described. This is to determine if the structure is residential, non-residential, or mixed-use. Also, structures in all 100-year and Poudre River 500-year floodplains cannot be used as a critical facility. (See Chapter 10 of City Code for definitions.) ☐ If in the Poudre River 100-year floodplain, the requirement to complete an Emergency Response and Preparedness Plan (ERPP) is discussed and the requirement for annual training drills and an annual update in the first quarter of every year is discussed. ☐ The report describes how the development is in compliance with the applicable floodplain regulation (Chapter 10 of City Code). (Examples: elevation of lowest floor above regulatory flood protection elevation, floodproofing, floodway regulation, erosion buffer zone regulation, no-rise, etc.) Fort Collins Utilities Floodplain Administration (970) 416-2632 Page 6 of 7 ☐ The type of foundation construction for the structures (i.e. slab-on-grade, crawl space, basement, etc.) is discussed in the report. ☐ The type of foundation matches with the lowest floor elevations and grading plan. ☐ If any of the garages are not going to be elevated above the regulatory flood protection elevation, the hydraulic venting requirements are discussed. ☐ For structures in the floodplain, a table is included (same table as on the Drainage/Grading Plan) that lists the following: ☐ City BFE at upstream end of structure ☐ FEMA BFE at upstream end of structure (if different than City BFE) ☐ Regulatory flood protection elevation ☐ Lowest floor elevation (bottom of basement or crawl space is considered lowest floor) ☐ Floodproofing elevation for non-residential structures (if applicable) ☐ Garage slab elevation ☐ HVAC elevation ☐ Elevations are referenced to the NAVD 1988 datum. ☐ If the floodplain use permit is not going to be submitted until the building permit is applied for, then a note must be included in the report that states the permit will be submitted at the time of building permit application. ☐ If floodproofing information is not submitted as part of the plans, then a note must be in the report stating that floodproofing information will be submitted at the time of the building permit application. ☐ A note is in the report stating that a FEMA elevation or floodproofing certificate will be completed and approved before the CO is issued. ☐ In the compliance section, Chapter 10 of City Code is listed. Floodplain Use Permit ☐ Floodplain Use Permit has been submitted for each structure. ☐ Permit fee has been submitted. ☐ All information on permit matches the plans. ☐ All information on permit meets floodplain regulations. Fort Collins Utilities Floodplain Administration (970) 416-2632 Page 7 of 7 FEMA CLOMR Approval ☐ FEMA has approved any necessary CLOMRs. ☐ The City has received copies of all updates to the FEMA submittal. Additional Comments: Floodplain terminology is defined in Chapter 10 of City Code. NOTE: Issues specific to individual sites may arise that result in additional requirements. These will be discussed during initial meetings with the applicant. Please refer to Chapter 10 of City Code for specific floodplain regulations. 19 APPENDIX B – HYDROLOGIC CALCULATIONS Subdivision:Polestar Project Name:Polestar Location:Fort Collins Project No.: Calculated By:ARJ Checked By:0 Date:4/21/25 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 A1 1.02 100%0.03 2.9%45%0.12 5.4%90%0.07 6.0%2%0.80 1.6%15.8% A2 0.58 100%0.19 32.5%45%0.00 0.0%90%0.12 18.1%2%0.27 0.9%51.6% A3 0.78 100%0.08 10.0%45%0.00 0.0%90%0.12 13.9%2%0.58 1.5%25.3% A4 1.23 100%0.58 47.6%45%0.00 0.0%90%0.23 16.7%2%0.42 0.7%65.0% A5 0.42 100%0.06 14.7%45%0.00 0.0%90%0.19 41.1%2%0.17 0.8%56.5% A6 1.03 100%0.61 59.7%45%0.09 4.1%90%0.05 4.4%2%0.27 0.5%68.7% A7 0.85 100%0.48 57.2%45%0.01 0.5%90%0.05 4.9%2%0.31 0.7%63.3% A8 0.58 100%0.39 66.7%45%0.00 0.0%90%0.11 16.8%2%0.09 0.3%83.8% A9.1 0.16 100%0.05 32.2%45%0.00 0.0%90%0.09 52.0%2%0.02 0.2%84.4% A9.2 0.03 100%0.01 37.2%45%0.00 0.0%90%0.01 16.4%2%0.01 0.9%54.5% A10 0.09 100%0.02 25.8%45%0.00 0.0%90%0.06 58.7%2%0.01 0.2%84.7% A11 0.13 100%0.04 34.7%45%0.00 0.0%90%0.05 33.6%2%0.04 0.6%68.8% A12 0.26 100%0.06 21.7%45%0.00 0.0%90%0.03 10.7%2%0.17 1.3%33.7% A13 0.40 100%0.03 7.2%45%0.00 0.0%90%0.23 53.1%2%0.13 0.7%61.0% A14 0.09 100%0.00 0.0%45%0.00 0.0%90%0.02 19.6%2%0.07 1.6%21.1% A15 0.49 100%0.06 11.6%45%0.00 0.0%90%0.06 10.3%2%0.38 1.5%23.5% A16 0.12 100%0.06 50.1%45%0.00 0.0%90%0.00 0.0%2%0.06 1.0%51.1% A17 0.43 100%0.04 9.0%45%0.00 0.0%90%0.09 19.1%2%0.30 1.4%29.6% A18 0.72 100%0.17 24.3%45%0.00 0.0%90%0.16 20.4%2%0.38 1.1%45.8% A19 0.35 100%0.13 38.5%45%0.00 0.0%90%0.05 12.0%2%0.17 1.0%51.5% B1 1.23 100%0.32 25.6%45%0.00 0.0%90%0.32 23.3%2%0.60 1.0%49.8% B2 0.31 100%0.18 58.1%45%0.00 0.0%90%0.07 19.2%2%0.06 0.4%77.7% C1 0.28 100%0.00 1.2%45%0.00 0.0%90%0.14 44.8%2%0.14 1.0%47.0% C2 0.32 100%0.02 6.2%45%0.00 0.0%90%0.08 23.0%2%0.22 1.4%30.5% D1 0.35 100%0.20 55.9%45%0.00 0.0%90%0.03 7.5%2%0.13 0.7%64.1% D2 0.22 100%0.11 50.1%45%0.00 0.0%90%0.03 12.0%2%0.08 0.7%62.9% D3 0.16 100%0.09 53.2%45%0.00 0.0%90%0.03 16.1%2%0.05 0.6%69.8% D4 0.25 100%0.14 54.9%45%0.00 0.0%90%0.01 5.2%2%0.10 0.8%60.9% D5 0.29 100%0.15 51.3%45%0.00 0.0%90%0.05 15.3%2%0.09 0.6%67.3% D6 0.28 100%0.16 57.3%45%0.00 0.0%90%0.01 2.4%2%0.11 0.8%60.5% D7 0.11 100%0.07 66.1%45%0.00 0.0%90%0.02 19.1%2%0.01 0.3%85.5% D8 0.19 100%0.15 78.9%45%0.00 0.0%90%0.02 11.4%2%0.02 0.2%90.5% E1 2.24 100%0.41 18.3%45%1.10 22.1%90%0.00 0.0%2%0.73 0.6%41.1% E2 0.54 100%0.19 34.6%45%0.23 19.1%90%0.00 0.0%2%0.12 0.5%54.2% E3 0.31 100%0.11 35.0%45%0.17 23.7%90%0.00 0.0%2%0.04 0.2%59.0% F1 3.92 100%0.04 1.0%45%0.53 6.0%90%1.00 22.9%2%2.36 1.2%31.2% Onsite Basins 20.77 47.5% OS1 0.61 100%0.00 0.0%45%0.00 0.0%90%0.09 13.5%2%0.52 1.7%15.2% OS2 0.09 100%0.03 36.0%45%0.0%90%0.01 13.8%2%0.04 1.0%50.8% Onsite Basins OS1 and OS2 21.47 46.6% 17W 10.20 45.0% COMPOSITE % IMPERVIOUS CALCULATIONS % Imp. Area (ac) Single Family Lots % Imp.Area (ac)Weighted % Imp. 39797.01 Weighted % Imp. Basins Total Weighted % Imp.Basin ID Total Area (ac)% Imp.Area (ac) Landscaping/Lawns % Imp.Area (ac)Weighted % Imp. Paved Roads and Walks Roofs Weighted % Imp. X:\3970000.all\3979701\Excel\Drainage\3979701 Drainage_Calcs_Template_v2.07.xlsm Page 1 of 2 4/21/2025 X:\3970000.all\3979701\Excel\Drainage\3979701 Drainage_Calcs_Template_v2.07.xlsm Page 2 of 2 4/21/2025 Subdivision:Polestar Project Name:Polestar Location:Fort Collins Project No.: Calculated By:ARJ Checked By:0 Date:4/21/25 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 10.0 11.0 12.0 13.0 14.0 15.0 16.0 17.0 18.0 19.0 20.0 21.0 Hydrologic Soils Group A1 1.02 C 0.95 0.03 0.03 0.03 0.55 0.12 0.07 0.08 0.95 0.07 0.06 0.08 0.20 0.80 0.16 0.20 0.31 0.39 A2 0.58 C 0.95 0.19 0.31 0.39 0.55 0.00 0.00 0.00 0.95 0.12 0.19 0.24 0.20 0.27 0.09 0.12 0.60 0.74 A3 0.78 C 0.95 0.08 0.09 0.12 0.55 0.00 0.00 0.00 0.95 0.12 0.15 0.18 0.20 0.58 0.15 0.19 0.39 0.49 A4 1.23 C 0.95 0.58 0.45 0.56 0.55 0.00 0.00 0.00 0.95 0.23 0.18 0.22 0.20 0.42 0.07 0.08 0.70 0.87 A5 0.42 C 0.95 0.06 0.14 0.17 0.55 0.00 0.00 0.00 0.95 0.19 0.43 0.54 0.20 0.17 0.08 0.10 0.65 0.82 A6 1.03 C 0.95 0.61 0.57 0.71 0.55 0.09 0.05 0.06 0.95 0.05 0.05 0.06 0.20 0.27 0.05 0.07 0.72 0.90 A7 0.85 C 0.95 0.48 0.54 0.68 0.55 0.01 0.01 0.01 0.95 0.05 0.05 0.06 0.20 0.31 0.07 0.09 0.67 0.84 A8 0.58 C 0.95 0.39 0.63 0.79 0.55 0.00 0.00 0.00 0.95 0.11 0.18 0.22 0.20 0.09 0.03 0.04 0.84 1.00 A9.1 0.16 C 0.95 0.05 0.31 0.38 0.55 0.00 0.00 0.00 0.95 0.09 0.55 0.69 0.20 0.02 0.02 0.03 0.87 1.00 A9.2 0.03 C 0.95 0.01 0.35 0.44 0.55 0.00 0.00 0.00 1.95 0.01 0.36 0.44 0.20 0.01 0.09 0.11 0.80 1.00 A10 0.09 C 0.95 0.02 0.25 0.31 0.55 0.00 0.00 0.00 0.95 0.06 0.62 0.77 0.20 0.01 0.02 0.02 0.88 1.00 A11 0.13 C 0.95 0.04 0.33 0.41 0.55 0.00 0.00 0.00 0.95 0.05 0.35 0.44 0.20 0.04 0.06 0.07 0.74 0.92 A12 0.26 C 0.95 0.06 0.21 0.26 0.55 0.00 0.00 0.00 0.95 0.03 0.11 0.14 0.20 0.17 0.13 0.17 0.45 0.56 A13 0.40 C 0.95 0.03 0.07 0.09 0.55 0.00 0.00 0.00 0.95 0.23 0.56 0.70 0.20 0.13 0.07 0.08 0.70 0.87 A14 0.09 B 0.95 0.00 0.00 0.00 0.55 0.00 0.00 0.00 0.95 0.02 0.21 0.26 0.15 0.07 0.12 0.15 0.32 0.41 A15 0.49 B 0.95 0.06 0.11 0.14 0.55 0.00 0.00 0.00 0.95 0.06 0.11 0.14 0.15 0.38 0.12 0.14 0.33 0.42 A16 0.12 B 0.95 0.06 0.48 0.59 0.55 0.00 0.00 0.00 0.95 0.00 0.00 0.00 0.15 0.06 0.07 0.09 0.55 0.69 A17 0.43 C 0.95 0.04 0.09 0.11 0.55 0.00 0.00 0.00 0.95 0.09 0.20 0.25 0.20 0.30 0.14 0.17 0.43 0.53 A18 0.72 B/C 0.95 0.17 0.23 0.29 0.55 0.00 0.00 0.00 0.95 0.16 0.22 0.27 0.15 0.38 0.08 0.10 0.53 0.66 A19 0.35 C 0.95 0.13 0.37 0.46 0.55 0.00 0.00 0.00 0.95 0.05 0.13 0.16 0.20 0.17 0.10 0.12 0.59 0.74 B1 1.23 C 0.95 0.32 0.24 0.30 0.55 0.00 0.00 0.00 0.95 0.32 0.25 0.31 0.20 0.60 0.10 0.12 0.59 0.73 B2 0.31 C 0.95 0.18 0.55 0.69 0.55 0.00 0.00 0.00 0.95 0.07 0.20 0.25 0.20 0.06 0.04 0.05 0.80 0.99 C1 0.28 C 0.95 0.00 0.01 0.01 0.55 0.00 0.00 0.00 0.95 0.14 0.47 0.59 0.20 0.14 0.10 0.12 0.58 0.73 C2 0.32 C 0.95 0.02 0.06 0.07 0.55 0.00 0.00 0.00 0.95 0.08 0.24 0.30 0.20 0.22 0.14 0.17 0.44 0.55 D1 0.35 B 0.95 0.20 0.53 0.66 0.55 0.00 0.00 0.00 0.95 0.03 0.08 0.10 0.15 0.13 0.05 0.07 0.66 0.83 D2 0.22 C 0.95 0.11 0.48 0.60 0.55 0.00 0.00 0.00 0.95 0.03 0.13 0.16 0.20 0.08 0.07 0.09 0.68 0.85 D3 0.16 C 0.95 0.09 0.51 0.63 0.55 0.00 0.00 0.00 0.95 0.03 0.17 0.21 0.20 0.05 0.06 0.07 0.73 0.92 D4 0.25 C 0.95 0.14 0.52 0.65 0.55 0.00 0.00 0.00 0.95 0.01 0.05 0.07 0.20 0.10 0.08 0.10 0.65 0.82 D5 0.29 C 0.95 0.15 0.49 0.61 0.55 0.00 0.00 0.00 0.95 0.05 0.16 0.20 0.20 0.09 0.06 0.08 0.71 0.89 D6 0.28 C 0.95 0.16 0.54 0.68 0.55 0.00 0.00 0.00 0.95 0.01 0.03 0.03 0.20 0.11 0.08 0.10 0.65 0.81 D7 0.11 C 0.95 0.07 0.63 0.78 0.55 0.00 0.00 0.00 0.95 0.02 0.20 0.25 0.20 0.01 0.03 0.03 0.86 1.00 D8 0.19 C 0.95 0.15 0.75 0.94 0.55 0.00 0.00 0.00 0.95 0.02 0.12 0.15 0.20 0.02 0.02 0.02 0.89 1.00 E1 2.24 C 0.95 0.41 0.17 0.22 0.55 1.10 0.27 0.34 0.95 0.00 0.00 0.00 0.20 0.73 0.06 0.08 0.51 0.64 E2 0.54 B/C 0.95 0.19 0.33 0.41 0.55 0.23 0.23 0.29 0.95 0.00 0.00 0.00 0.15 0.12 0.03 0.04 0.60 0.75 E3 0.31 B/C 0.95 0.11 0.33 0.42 0.55 0.17 0.29 0.36 0.95 0.00 0.00 0.00 0.15 0.04 0.02 0.02 0.64 0.80 F1 3.92 C 0.95 0.04 0.01 0.01 0.55 0.53 0.07 0.09 0.95 1.00 0.24 0.30 0.20 2.36 0.12 0.15 0.45 0.56 OS1 0.61 C 0.95 0.00 0.00 0.00 0.55 0.00 0.00 0.00 0.95 0.09 0.14 0.18 0.20 0.52 0.17 0.21 0.31 0.39 OS2 0.09 C 0.95 0.03 0.34 0.43 0.55 0.00 0.00 0.00 0.95 0.01 0.15 0.18 0.20 0.04 0.10 0.12 0.59 0.73 COMPOSITE RUNOFF COEFFICIENT CALCULATIONS Basin ID Area (ac)2 - YEAR C 100 - YEAR C Runoff Coefficient Area (ac)2 - YEAR C 100 - YEAR C 39797.01 Total Area (ac)Runoff Coefficient Area (ac)2 - YEAR C 100 - YEAR C Runoff Coefficient Basins Total Weighted 100 YEAR CRunoff Coefficient Area (ac)2 - YEAR C 100 - YEAR C Paved Roads/Ashphalt Single Family Lots Roofs Lawns Basins Total Weighted 2 YEAR C X:\3970000.all\3979701\Excel\Drainage\3979701 Drainage_Calcs_Template_v2.07.xlsm Page 1 of 2 4/21/2025 X:\3970000.all\3979701\Excel\Drainage\3979701 Drainage_Calcs_Template_v2.07.xlsm Page 2 of 2 4/21/2025 Subdivision:Polestar Project Name:Polestar Location:Fort Collins Project No.: Calculated By:ARJ Checked By:0 Date:4/21/25 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 BASIN D.A.Hydrologic Impervious C2 C100 L S o t i - 2Year t i - 100 Year L t S t K VEL.t t COMP.t c-2 Year COMP.t c 100 - Year TOTAL Urbanized t c t c-2 Year t c-100 Year ID (ac)Soils Group (%)(ft)(%)(min)(min)(ft)(%)(ft/s)(min)(min)(min)LENGTH (ft)(min)(min)(min) A1 1.02 C 16%0.31 0.39 15 2.0%20.7 18.7 104 8.8%5.0 1.5 1.2 21.9 19.8 118.9 10.7 11.0 11.0 A2 0.58 C 52%0.60 0.74 42.5 2.0%22.4 15.8 105 2.1%20.0 2.9 0.6 23.0 16.4 147.2 10.8 11.0 11.0 A3 0.78 C 25%0.39 0.49 50 4.0%27.3 23.5 151 2.2%15.0 2.2 1.1 28.4 24.6 200.7 11.1 11.0 11.0 A4 1.23 C 65%0.70 0.87 12 3.0%8.3 4.7 449 1.0%20.0 2.0 3.8 12.1 8.5 461.1 12.6 12.0 9.0 A5 0.42 C 57%0.65 0.82 5 2.0%6.8 4.3 55 1.1%15.0 1.5 0.6 7.4 4.9 60.0 10.3 7.0 5.0 A6 1.03 C 69%0.72 0.90 13 2.0%9.4 5.0 643 0.8%20.0 1.8 6.0 15.4 11.0 655.5 13.6 14.0 11.0 A7 0.85 C 63%0.67 0.84 13 2.0%10.5 6.3 595 0.9%20.0 1.9 5.2 15.7 11.5 607.8 13.4 13.0 12.0 A8 0.58 C 84%0.84 1.00 12 3.0%5.3 2.1 221 1.3%20.0 2.3 1.6 7.0 3.7 233.4 11.3 7.0 5.0 A9.1 0.16 C 84%0.87 1.00 5 2.0%3.4 1.5 67 0.6%20.0 1.6 0.7 4.1 2.2 72.0 10.4 5.0 5.0 A9.2 0.03 C 54%0.80 1.00 5 2.0%4.6 1.6 5 10.0%20.0 6.3 0.0 4.6 1.6 10.0 10.1 5.0 5.0 A10 0.09 C 85%0.88 1.00 5 2.0%3.3 1.5 30 3.4%15.0 2.8 0.2 3.5 1.7 35.0 10.2 5.0 5.0 A11 0.13 C 69%0.74 0.92 5 2.0%5.5 2.7 60 2.0%15.0 2.1 0.5 5.9 3.1 65.0 10.4 6.0 5.0 A12 0.26 C 34%0.45 0.56 5 2.0%9.9 8.1 102 0.7%15.0 1.3 1.3 11.2 9.5 107.3 10.6 11.0 9.0 A13 0.40 B 61%0.70 0.87 5 2.0%6.1 3.5 50 1.0%15.0 1.5 0.6 6.7 4.0 55.0 10.3 7.0 5.0 A14 0.09 B 21%0.32 0.41 5 2.0%11.8 10.6 20 2.4%15.0 2.3 0.1 11.9 10.7 25.0 10.1 10.0 10.0 A15 0.49 B 24%0.33 0.42 5 2.0%11.6 10.4 119 1.4%15.0 1.8 1.1 12.7 11.5 123.5 10.7 11.0 11.0 A16 0.12 C 51%0.55 0.69 5 2.0%8.4 6.3 54 0.7%15.0 1.3 0.7 9.1 7.0 59.1 10.3 9.0 7.0 A17 0.43 B/C 30%0.43 0.53 5 2.0%10.2 8.6 113 1.8%20.0 2.7 0.7 10.9 9.3 118.0 10.7 11.0 9.0 A18 0.72 C 46%0.53 0.66 30 3.4%18.0 13.8 150 0.6%15.0 1.1 2.2 20.2 16.0 180.0 11.0 11.0 11.0 A19 0.35 C 52%0.59 0.74 5 3.4%6.5 4.6 30 3.9%15.0 3.0 0.2 6.7 4.8 35.0 10.2 7.0 5.0 B1 1.23 C 50%0.59 0.73 24 2.0%17.1 12.2 175 0.5%20.0 1.4 2.1 19.2 14.3 199.0 11.1 11.0 11.0 B2 0.31 C 78%0.80 0.99 24 2.0%10.1 3.5 204 1.8%20.0 2.7 1.3 11.4 4.8 228.0 11.3 11.0 5.0 C1 0.28 C 47%0.58 0.73 3 25.0%2.6 1.9 54 5.9%20.0 4.9 0.2 2.8 2.1 57.0 10.3 5.0 5.0 C2 0.32 B 31%0.44 0.55 5 2.0%10.1 8.4 62 2.0%15.0 2.1 0.5 10.6 8.9 67.0 10.4 10.0 9.0 D1 0.35 C 64%0.66 0.83 24 2.0%14.5 9.0 54 0.8%20.0 1.7 0.5 15.1 9.5 78.1 10.4 10.0 10.0 D2 0.22 C 63%0.68 0.85 24 2.0%14.1 8.5 87 0.8%20.0 1.7 0.8 15.0 9.3 111.0 10.6 11.0 9.0 D3 0.16 C 70%0.73 0.92 24 2.0%12.2 6.1 60 0.8%20.0 1.7 0.6 12.8 6.7 84.0 10.5 10.0 7.0 D4 0.25 C 61%0.65 0.82 24 2.0%14.8 9.4 65 0.8%20.0 1.7 0.6 15.5 10.0 89.0 10.5 10.0 10.0 D5 0.29 C 67%0.71 0.89 13 2.0%9.5 5.1 231 2.0%20.0 2.8 1.4 10.9 6.5 244.0 11.4 11.0 7.0 D6 0.28 C 60%0.65 0.81 13 2.0%11.0 7.1 264 2.0%20.0 2.8 1.6 12.6 8.6 277.0 11.5 12.0 9.0 D7 0.11 C 85%0.86 1.00 24 2.0%8.2 3.3 60 0.8%20.0 1.7 0.6 8.7 3.9 84.0 10.5 9.0 5.0 D8 0.19 C 90%0.89 1.00 24 2.0%7.1 3.3 83 0.8%20.0 1.7 0.8 7.9 4.1 107.0 10.6 8.0 5.0 E1 2.24 C 41%0.08 0.51 130 4.0%62.8 36.4 505 1.0%20.0 2.0 4.1 67.0 40.5 635.3 13.5 14.0 14.0 E2 0.54 B/C 54%0.04 0.60 50 2.0%50.8 24.2 270 1.0%20.0 2.0 2.3 53.1 26.5 320.0 11.8 12.0 12.0 E3 0.31 B/C 59%0.02 0.64 50 2.0%51.8 22.1 143 1.1%20.0 2.1 1.2 52.9 23.2 193.0 11.1 11.0 11.0 F1 3.92 C 31%0.15 0.45 50 1.0%57.4 39.6 475 0.5%20.0 1.4 5.6 63.0 45.1 525.0 12.9 13.0 13.0 OS1 0.61 C 15%0.21 0.31 46 1.7%43.4 38.6 66 1.4%5.0 0.6 1.9 45.3 40.4 112.0 10.6 11.0 11.0 OS2 0.09 C 51%0.12 0.59 50 1.0%59.1 31.1 215 3.0%20.0 3.5 1.0 60.2 32.1 265.0 11.5 11.0 11.0 NOTES: Velocity V = K*St^0.5 STANDARD FORM SF-2 TIME OF CONCENTRATION SUB-BASIN Time of Concentration -Check 39797.01 FINAL(Tc)DATA INITIAL/OVERLAND (Ti) TRAVEL TIME (Tt) X:\3970000.all\3979701\Excel\Drainage\3979701 Drainage_Calcs_Template_v2.07.xlsm Page 1 of 1 4/21/2025 Project Name:Polestar Subdivision:Polestar Project No.: Location:Fort Collins Calculated By:ARJ Design Storm:Checked By:0 Date: TRAVEL TIME STREET De s i g n P o i n t Ba s i n I D Ar e a ( A c ) Ru n o f f C o e f f . tc ( m i n ) C* A ( A c ) I ( i n / h r ) Q ( c f s ) tc ( m i n ) C* A ( a c ) I ( i n / h r ) Q ( c f s ) Qst r e e t ( c f s ) C* A ( a c ) Sl o p e ( % ) Qpi p e ( c f s ) C* A ( a c ) Sl o p e ( % ) Pi p e S i z e ( i n c h e s ) Le n g t h ( f t ) Ve l o c i t y ( f p s ) tt ( m i n ) REMARKS E1 2.24 0.08 14.0 0.18 1.92 0.35 Flow from SWMM 17W 11.68 OS1 0.61 0.21 11.0 0.13 2.13 0.28 OS2 0.09 0.12 11.0 0.01 2.13 0.02 Flow into Pan 1e 12.3 Flow into Pan 2e E2 0.54 0.04 12.0 0.02 2.05 0.04 12.4 Flow into pan and then swale Ongrade inlet - Drains to Pond 3e E3 0.31 0.02 11.0 0.01 2.13 0.02 Runoff Collected Via Nyloplastic and ADS pipe 19a A19 0.35 0.59 7.0 0.20 2.52 0.50 7.00 0.20 2.52 0.5 0.5 0.2 0.5%15 194 1.4 2.3 Drains - Basin A19 Runoff Collected Via Trench Drain and ADS pipe 18a A18 0.72 0.53 11.0 0.38 2.13 0.81 11.0 0.58 2.13 1.2 1.2 0.6 0.5%18 139 1.4 1.6 Drains - Basin A19 and A18 Runoff Collected Via Nyloplastic and ADS pipe 17a A17 0.43 0.43 11.0 0.18 2.13 0.38 12.6 0.76 2.01 1.5 1.5 0.8 0.3%18 90 1.2 1.3 Drains - Basin A19, A18, and A17 Runoff Collected Via Nyloplastic and ADS pipe 13a A13 0.40 0.70 7.0 0.28 2.52 0.71 0.7 0.3 0.9%12 50 1.9 0.4 Drains Basin A13 Runoff Collected Via Nyloplastic and ADS pipe 15a A15 0.49 0.33 11.0 0.16 2.13 0.34 11.0 0.44 2.13 0.9 0.9 0.2 0.8%18 90 1.8 0.8 Drains Basin A13, and A15 Runoff From alleys, open space and temple frontage 2a A2 0.58 0.60 11.0 0.35 2.13 0.75 13.4 2.01 1.96 3.9 3.9 0.35 0.70%118 1.7 1.2 Basins A8, A4, and A3, A2 Total infow to sump inlet at DP 6a 6a A6 1.03 0.72 14.0 0.74 1.92 1.42 14.6 2.75 1.89 5.2 Basins A6, A8, A4, and A3, A2 Toatl runoff into RG Forebay - Basin A2-A19 1.5 22.9 5.35 1.49 8.0 8.0 5.3 0.5%30 DIRECT RUNOFF TOTAL RUNOFF STREET PIPE STANDARD FORM SF-3 STORM DRAINAGE SYSTEM DESIGN (RATIONAL METHOD PROCEDURE) X:\3970000.all\3979701\Excel\Drainage\3979701 Drainage_Calcs_Template_v2.07.xlsm Page 1 of 2 4/21/2025 Project Name:Polestar Subdivision:Polestar Project No.: Location:Fort Collins Calculated By:ARJ Design Storm:Checked By:0 Date: TRAVEL TIME STREET De s i g n P o i n t Ba s i n I D Ar e a ( A c ) Ru n o f f C o e f f . tc ( m i n ) C* A ( A c ) I ( i n / h r ) Q ( c f s ) tc ( m i n ) C* A ( a c ) I ( i n / h r ) Q ( c f s ) Qst r e e t ( c f s ) C* A ( a c ) Sl o p e ( % ) Qpi p e ( c f s ) C* A ( a c ) Sl o p e ( % ) Pi p e S i z e ( i n c h e s ) Le n g t h ( f t ) Ve l o c i t y ( f p s ) tt ( m i n ) REMARKS DIRECT RUNOFF TOTAL RUNOFF STREET PIPE STANDARD FORM SF-3 STORM DRAINAGE SYSTEM DESIGN (RATIONAL METHOD PROCEDURE) A1 1.02 0.31 11.0 0.32 2.13 0.68 Overflow into the Polestar Detention Pond 1.6 22.9 5.67 1.49 8.5 8.5 0.5%30 Overflows and is then Piped in Type D inlet 1b B1 1.23 0.59 11.0 0.72 2.13 1.53 2b B2 0.31 0.80 11.0 0.25 2.13 0.53 Run-off into rain garden 2.1 11.0 0.97 2.13 2.1 2.1 6.5%12 Overflow into pond Runoff into RG 1c C1 0.28 0.58 5.0 0.16 2.85 0.46 Runoff into RG 2c C2 0.32 0.44 10.0 0.14 2.21 0.31 0.3 0.44%10 7d D7 0.11 0.86 9.0 0.10 2.30 0.23 8d D8 0.19 0.89 8.0 0.17 2.40 0.41 9.0 0.27 2.30 0.6 Runoff into rain garden 3.1 10.0 0.57 2.21 1.3 1.3 1.8%12 Overflow into pond piped in ADS pipe Basin D1 1d D1 0.35 0.66 10.0 0.23 2.21 0.51 Drains via curb cut to RG 2d D2 0.22 0.68 11.0 0.15 2.13 0.32 11.0 0.38 2.13 0.8 Basins D1 and D2 Drains via curb cut to RG 3d D3 0.16 0.73 10.0 0.12 2.21 0.27 11.0 0.50 2.13 1.1 Basins D1,D2 and D3 Runoff into rain garden 4.1 11.0 0.50 2.13 1.1 1.1 0.5%18 60 1.4 0.7 Overflow into pond Runoff into RG 5d D5 0.29 0.71 11.0 0.21 2.13 0.45 Total Runoff into RG 4d D4 0.25 0.65 10.0 0.16 2.21 0.35 11.0 0.37 2.13 0.8 Piped runoff into type C inlet 4.2 11.7 0.87 2.07 1.8 1.8 0.5%24 173 1.4 2.0 Runoff Drains into RG Drains via Curb Cut 6d D6 0.28 0.65 12.0 0.18 2.05 0.37 Runoff Drains into Polestar Detention Pond 4.3 13.7 1.05 1.94 2.0 2.0 0.8%24 Piped Basin D6-D1 Notes: Street and Pipe C*A values are determined by Q/i using the catchment's intensity value. X:\3970000.all\3979701\Excel\Drainage\3979701 Drainage_Calcs_Template_v2.07.xlsm Page 2 of 2 4/21/2025 Project Name:Polestar Subdivision:Polestar Project No.: Location:Fort Collins Calculated By:ARJ Design Storm:Checked By:0 Date: TRAVEL TIME STREET De s i g n P o i n t Ba s i n I D Ar e a ( a c ) Ru n o f f C o e f f . tc ( m i n ) C* A ( a c ) I ( i n / h r ) Q ( c f s ) tc ( m i n ) C* A ( a c ) I ( i n / h r ) Q ( c f s ) Qst r e e t ( c f s ) C* A ( a c ) Sl o p e ( % ) Qpi p e ( c f s ) C* A ( a c ) Sl o p e ( % ) Pi p e S i z e ( i n c h e s ) Le n g t h ( f t ) Ve l o c i t y ( f p s ) tt ( m i n ) REMARKS E1 2.24 0.51 14.0 1.14 6.71 7.6 Flow from SWMM 17W 59.9 OS1 0.61 0.31 11.0 0.19 7.42 1.4 OS2 0.09 0.59 11.0 0.05 7.42 0.4 Flow into Pan 1e 69.4 Flow into Pan 2e E2 0.54 0.60 12.0 0.32 7.16 2.3 71.7 Flow into pan and then swale 10a A10 0.09 1.00 5.0 0.09 9.95 0.9 0.9 0.1 4.8%6 60 4.4 0.2 STORM DRAINAGE SYSTEM DESIGN STANDARD FORM SF-3 (RATIONAL METHOD PROCEDURE) PIPE 100-Year DIRECT RUNOFF TOTAL RUNOFF 4/21/25 STREET X:\3970000.all\3979701\Excel\Drainage\3979701 Drainage_Calcs_Template_v2.07.xlsm Page 1 of 2 4/21/2025 Project Name:Polestar Subdivision:Polestar Project No.: Location:Fort Collins Calculated By:ARJ Design Storm:Checked By:0 Date: TRAVEL TIME STREET De s i g n P o i n t Ba s i n I D Ar e a ( a c ) Ru n o f f C o e f f . tc ( m i n ) C* A ( a c ) I ( i n / h r ) Q ( c f s ) tc ( m i n ) C* A ( a c ) I ( i n / h r ) Q ( c f s ) Qst r e e t ( c f s ) C* A ( a c ) Sl o p e ( % ) Qpi p e ( c f s ) C* A ( a c ) Sl o p e ( % ) Pi p e S i z e ( i n c h e s ) Le n g t h ( f t ) Ve l o c i t y ( f p s ) tt ( m i n ) REMARKS STORM DRAINAGE SYSTEM DESIGN STANDARD FORM SF-3 (RATIONAL METHOD PROCEDURE) PIPE 100-Year DIRECT RUNOFF TOTAL RUNOFF 4/21/25 STREET Runoff drains to sump inlet at Dp 7a 7a A7 0.85 0.84 12.0 0.71 7.16 5.1 1.4 22.6 3.24 5.25 17.0 17.0 3.2 0.5%30 22 1.4 0.3 Runoff From alley and temple frontage 8a A8 0.58 1.00 5.0 0.58 9.95 5.8 5.8 0.58 0.87%217 1.9 1.9 Drains to Plum Street Basin A8 Runoff From alleys and temple frontage 4a A4 1.23 0.87 9.0 1.07 8.03 8.6 9.0 1.65 8.03 13.2 13.2 1.07 0.87%83 1.9 0.7 Basins A8 and A4 Runoff From alleys, open space and temple frontage 3a A3 0.78 0.49 11.0 0.38 7.42 2.8 11.0 2.03 7.42 15.1 15.1 0.38 0.87%74 1.9 0.7 Basins A8, A4, and A3 Runoff From alleys, open space and temple frontage 2a A2 0.58 0.74 11.0 0.43 7.42 3.2 11.7 2.46 7.24 17.8 17.8 0.43 0.70%118 1.7 1.2 Basins A8, A4, and A3, A2 Total infow to sump inlet at DP 6a 6a A6 1.03 0.90 11.0 0.92 7.42 6.8 12.9 3.38 6.94 23.5 Basins A6, A8, A4, and A3, A2 Toatl runoff into RG Forebay - Basin A2-A19 1.5 22.9 6.62 5.21 34.5 34.5 6.6 0.5%30 A1 1.02 0.39 11.0 0.40 7.42 3.0 Overflow into the Polestar Detention Pond 1.6 7.02 22.9 7.02 5.21 36.6 36.6 0.5%30 Overflows and is then Piped in Type D inlet 1b B1 1.23 0.73 11.0 0.90 7.42 6.7 2b B2 0.31 0.99 5.0 0.31 9.95 3.1 Run-off into rain garden 2.1 11.0 1.21 7.42 9.0 9.0 6.5%12 Overflow into pond Runoff into RG 1c C1 0.28 0.73 5.0 0.21 9.95 2.1 Runoff into RG 2c C2 0.32 0.55 9.0 0.18 8.03 1.4 1.4 0.44%10 7d D7 0.11 1.00 5.0 0.11 9.95 1.1 8d D8 0.19 1.00 5.0 0.19 9.95 1.9 5.0 0.30 9.95 3.0 Runoff into rain garden 3.1 9.0 0.69 8.03 5.5 5.5 1.8%12 Overflow into pond piped in ADS pipe Basin D1 1d D1 0.35 0.83 10.0 0.29 7.72 2.2 Drains via curb cut to RG 2d D2 0.22 0.85 9.0 0.18 8.03 1.4 10.0 0.47 7.72 3.6 Basins D1 and D2 Drains via curb cut to RG 3d D3 0.16 0.92 7.0 0.15 8.80 1.3 10.0 0.62 7.72 4.8 Basins D1,D2 and D3 Runoff into rain garden 4.1 10.0 0.62 7.72 4.8 4.8 0.5%18 60 1.4 0.7 Overflow into pond Runoff into RG 5d D5 0.29 0.89 7.0 0.26 8.80 2.3 Total Runoff into RG 4d D4 0.25 0.82 10.0 0.21 7.72 1.6 10.0 0.47 7.72 3.6 Piped runoff into type C inlet 4.2 10.7 1.09 7.51 8.2 8.2 0.5%24 173 1.4 2.0 Runoff Drains into RG Drains via Curb Cut 6d D6 0.28 0.81 9.0 0.23 8.03 1.8 Runoff Drains into Polestar Detention Pond 4.3 12.7 1.32 6.99 9.2 9.2 0.8%24 Piped Basin D6-D1 Notes: Street and Pipe C*A values are determined by Q/i using the catchment's intensity value. X:\3970000.all\3979701\Excel\Drainage\3979701 Drainage_Calcs_Template_v2.07.xlsm Page 2 of 2 4/21/2025 Subdivision:Polestar Village Project Name:Polestar Location:Fort Collins Project No.: Calculated By:ARJ Checked By:0 Overflow at DP 5.1 Date:8/21/24 Value Units Va 8.5 ft/s Gs 2.5 Gs 32.2 (ft/s ^2 ) C 1 D(50)0.75 feet D(50)9 inches *using typem riprap - 12" OVERFLOW CHANNEL CC - RIPRAP CALCULATIONS 39797.01 RIP-RAP METHOD - ISBASH Method D50 = stone size (ft) V a = average channel velocity (ft/s) G s = specific gravity of stone G = gravitational constant (ft/s ^2 ) C = 0.86 for high turbulence zones 1.20 for low turbulence zones Subdivision:Polestar Project Name:Polestar Location:Fort Collins Project No.:39797.01 Calculated By:ARJ Checked By:0 Date:4/21/25 DESIGN POINT - 2.1 DESIGN POINT - 3.1 DESIGN POINT - 4.3 Design Point - 3e DESIGN POINT - 1.6 Notes Q100 (cfs):9.0 5.5 9.2 1.5 36.6 Conduit Pipe Pipe Pipe Pipe Pipe D c , Pipe Diameter (in):12 12 18 15 30 W , Box Width (ft):N/A N/A N/A N/A N/A H , Box Height (ft):N/A N/A N/A N/A N/A Y t , Tailwater Depth (ft):0.40 0.40 0.40 0.20 1.88 If unknown, use Y t /D c (or H )=0.4 Y t /Dc or Y t /H 0.40 0.40 0.27 0.16 0.75 Pond Tw assumed to be at .75 Yt/H for DP 1.5 Q/D2.5 or Q/(WH3/2)8.98 5.54 3.35 0.85 3.70 Supercritical?Yes Yes Yes Yes Yes Y n , Normal Depth (ft) [Supercritical]:0.72 0.58 0.63 0.53 2.50 D a ,H a (in) [Supercritical]:0.86 0.79 1.07 0.89 2.50 D a =(D c +Y n )/2 Riprap d 50 (in) [Supercritical]:7.79 4.93 7.51 2.93 3.61 Riprap d 50 (in) [Subcritical]:N/A N/A N/A N/A N/A Required Riprap Size:L L L L L Fig. 9-38 or Fig. 9-36 d 50 (in):9 9 9 9 9 Using type M Riprap Expansion Factor, 1/(2 tan):3.00 3.00 3.00 3.00 3.00 Read from Fig. 9-35 or 9-36 0.17 0.17 0.17 0.17 0.17 Erosive Soils?No No No Yes No Area of Flow,A t (ft2):1.28 0.79 1.32 0.30 5.23 A t =Q/V Length of Protection, L p (ft):6.6 2.9 5.4 0.7 0.9 L=(1/(2 tan ))(At/Yt - D) Min Length (ft)3.0 3.0 4.5 3.8 7.5 Min L=3D or 3H Max Length (ft)10.0 10.0 15.0 12.5 25.0 Max L=10D or 10H Min Bottom Width,T (ft):3.2 2.0 3.3 1.5 2.8 T=2*(Lp*tan)+W Design Length (ft)7.0 3.0 6.0 3.8 7.5 Design Width (ft)3.2 2.0 3.3 1.5 2.8 Riprap Depth (in)18 18 18 18 18 Depth=2(d50) Type II Bedding Depth (in)*6 6 6 6 6 *Not used if Soil Riprap Cutoff Wall No No No No Yes Cutoff Wall Depth (ft)2.0 Depth of Riprap and Base Cutoff Wall Width (ft)8.3 * For use when the flow in the culvert is supercritical (and less than full). STORM DRAIN SYSTEM PIPE OUTFALL RIPRAP SIZING CALCULATIONS USE TYPE M RIPRAP - TYPE L USE IS NOT ALLOWED PER CITY OF FORT COLLINS -2018 FCSCM X:\3970000.all\3979701\Excel\Drainage\3979701 Drainage_Calcs_Template_v2.07.xlsm Page 1 of 2 4/21/2025 X:\3970000.all\3979701\Excel\Drainage\3979701 Drainage_Calcs_Template_v2.07.xlsm Page 2 of 2 4/21/2025 Subdivision:Polestar Project Name:Polestar Location:Fort Collins Project No.:39797.01 Calculated By:ARJ Checked By:0 Date:11/13/24 Private Drains De s i g n P o i n t Q ( c f s ) Mi n P i p e S l o p e Mi n P i p e S i z e ( F T ) Pr o p o s e d P i p e S i z e ( i n c h e s ) 19a 2.6 0.50%1.01 15 18a 5.4 0.50%1.33 18 17a 6.7 0.34%1.51 18 13a 3.5 0.90%0.98 12 15a 4.2 0.78%1.11 18 14a 4.3 0.78%1.13 18 16a 4.8 0.78%1.17 18 10a 0.9 4.75%0.44 6 1.1 5.2 0.50%1.32 18 12a 6.2 0.50%1.40 18 11a 1.2 5.00%0.49 6 1.2 13.4 0.50%1.87 24 9.1A 1.6 2.50%0.62 8 9.2a 14.2 0.50%1.91 24 4.1 4.8 0.47%1.29 18 4.2 8.2 0.50%1.56 24 3.1 5.5 1.80%0.99 12 2.1 9.0 6.54%0.99 12 2c 1.4 0.44%0.83 10 n=0.013 typ. n=0.012 for DP17a,13a and 3.1 See Equation Below: X:\3970000.all\3979701\Excel\Drainage\3979701 Drainage_Calcs_Template_v2.07.xlsm Page 1 of 1 11/25/2024 20 APPENDIX C – HYDRAULIC CALCULATIONS Subdivision:Polestar Project Name:Polestar Location:Fort Collins Project No.: Design Storm:100-Year Calculated By:ARJ Checked By: Date:May-24 Input Type of Grate 12" Pedestrian Head (ft)0.2 Properties Orifice Flow Area (in)50.6 Orifice Flow Area (ft)0.35 Weir Flow Perimeter (in)43.25 Weir Flow Perimeter (ft)3.60 Solution Capacity (cfs)0.75 Capacity (gpm)337.28 Design Point 100 YR (cfs)9.1a 1.6 No of inlets 3 Total Cap. (cfs)2.25 FS 1.42 uses the lesser of these two equations REV 2.1.21 39797.01 DISCLAIMER: SAFETY FACTORS ARE NOT INCLUDED IN THESE CALCULATIONS. ACTUAL CALCULATIONS SHOULD BE CARRIED OUT AND VERIFIED BY THE DESIGN ENGINEER TAKING INTO ACCOUNT ALL LOCAL CONDITIONS. NYLOPLAST RECOMMENDS USING A MINIMUM SAFETY FACTOR OF 1.25 FOR PAVED AREAS AND 2.0 FOR TURF AREAS. ADS/NYLOPLAST IS NOT RESPONSIBLE FOR MISUSE OF THIS TOOL. Subdivision:Polestar Project Name:Polestar Location:Fort Collins Project No.: Design Storm:100-Year Calculated By:ARJ Checked By: Date:May-24 Input Type of Grate Type C Head (ft)0.1 Properties Orifice Flow Area (in)907.2 Orifice Flow Area (ft)6.30 Weir Flow Perimeter (in)144.00 Weir Flow Perimeter (ft)12.00 Solution Capacity (cfs)1.26 Capacity (gpm)567.12 Design Point 100 YR (cfs)9.2a 14.2 No of inlets 1 Total Cap. (cfs)1.26 FS 0.09 Note: using CDOT Type C Inlet uses the lesser of these two equations REV 2.1.21 39797.01 DISCLAIMER: SAFETY FACTORS ARE NOT INCLUDED IN THESE CALCULATIONS. ACTUAL CALCULATIONS SHOULD BE CARRIED OUT AND VERIFIED BY THE DESIGN ENGINEER TAKING INTO ACCOUNT ALL LOCAL CONDITIONS. NYLOPLAST RECOMMENDS USING A MINIMUM SAFETY FACTOR OF 1.25 FOR PAVED AREAS AND 2.0 FOR TURF AREAS. ADS/NYLOPLAST IS NOT RESPONSIBLE FOR MISUSE OF THIS TOOL. Subdivision:Polestar Project Name:Polestar Location:Fort Collins Project No.: Design Storm:100-Year Calculated By:ARJ Checked By: Date:May-24 Input Type of Grate 15" Pedestrian Head (ft)0.18 Properties Orifice Flow Area (in)81.25 Orifice Flow Area (ft)0.56 Weir Flow Perimeter (in)54.25 Weir Flow Perimeter (ft)4.52 Solution Capacity (cfs)1.14 Capacity (gpm)513.78 Design Point 100 YR (cfs)10a 0.9 No of inlets 1 Total Cap. (cfs)1.14 FS 1.28 uses the lesser of these two equations REV 2.1.21 39797.01 DISCLAIMER: SAFETY FACTORS ARE NOT INCLUDED IN THESE CALCULATIONS. ACTUAL CALCULATIONS SHOULD BE CARRIED OUT AND VERIFIED BY THE DESIGN ENGINEER TAKING INTO ACCOUNT ALL LOCAL CONDITIONS. NYLOPLAST RECOMMENDS USING A MINIMUM SAFETY FACTOR OF 1.25 FOR PAVED AREAS AND 2.0 FOR TURF AREAS. ADS/NYLOPLAST IS NOT RESPONSIBLE FOR MISUSE OF THIS TOOL. Subdivision:Polestar Project Name:Polestar Location:Fort Collins Project No.: Design Storm:100-Year Calculated By:ARJ Checked By: Date:May-24 Input Type of Grate 18" Drop In Head (ft)0.6 Properties Orifice Flow Area (in)84.61 Orifice Flow Area (ft)0.58 Weir Flow Perimeter (in)48.00 Weir Flow Perimeter (ft)4.00 Solution Capacity (cfs)2.18 Capacity (gpm)976.83 Design Point 100 YR (cfs)11a 1.2 No of inlets 1 Total Cap. (cfs)2.18 FS 1.82 uses the lesser of these two equations REV 2.1.21 39797.01 DISCLAIMER: SAFETY FACTORS ARE NOT INCLUDED IN THESE CALCULATIONS. ACTUAL CALCULATIONS SHOULD BE CARRIED OUT AND VERIFIED BY THE DESIGN ENGINEER TAKING INTO ACCOUNT ALL LOCAL CONDITIONS. NYLOPLAST RECOMMENDS USING A MINIMUM SAFETY FACTOR OF 1.25 FOR PAVED AREAS AND 2.0 FOR TURF AREAS. ADS/NYLOPLAST IS NOT RESPONSIBLE FOR MISUSE OF THIS TOOL. Subdivision:Polestar Project Name:Polestar Location:Fort Collins Project No.: Design Storm:100-Year Calculated By:ARJ Checked By: Date:May-24 Input Type of Grate 24" Drop In Head (ft)0.4 Properties Orifice Flow Area (in)164.94 Orifice Flow Area (ft)1.14 Weir Flow Perimeter (in)66.28 Weir Flow Perimeter (ft)5.52 Solution Capacity (cfs)3.46 Capacity (gpm)1554.81 Design Point 100 YR (cfs)12a 6.2 No of inlets 1 Total Cap. (cfs)3.46 FS 0.56 Note: Additional inlets one 12" - Drop in inlet and one 18" drop in inlet have been added to capture flow along this run associated with DP 12a along the swale and at Tee's uses the lesser of these two equations REV 2.1.21 39797.01 DISCLAIMER: SAFETY FACTORS ARE NOT INCLUDED IN THESE CALCULATIONS. ACTUAL CALCULATIONS SHOULD BE CARRIED OUT AND VERIFIED BY THE DESIGN ENGINEER TAKING INTO ACCOUNT ALL LOCAL CONDITIONS. NYLOPLAST RECOMMENDS USING A MINIMUM SAFETY FACTOR OF 1.25 FOR PAVED AREAS AND 2.0 FOR TURF AREAS. ADS/NYLOPLAST IS NOT RESPONSIBLE FOR MISUSE OF THIS TOOL. Subdivision:Polestar Project Name:Polestar Location:Fort Collins Project No.: Design Storm:100-Year Calculated By:ARJ Checked By: Date:May-24 Input Type of Grate 18" Drop In Head (ft)0.55 Properties Orifice Flow Area (in)84.61 Orifice Flow Area (ft)0.58 Weir Flow Perimeter (in)48.00 Weir Flow Perimeter (ft)4.00 Solution Capacity (cfs)2.08 Capacity (gpm)935.24 Design Point 100 YR (cfs)13a 3.5 No of inlets 3 Total Cap. (cfs)6.25 FS 1.80 uses the lesser of these two equations REV 2.1.21 39797.01 DISCLAIMER: SAFETY FACTORS ARE NOT INCLUDED IN THESE CALCULATIONS. ACTUAL CALCULATIONS SHOULD BE CARRIED OUT AND VERIFIED BY THE DESIGN ENGINEER TAKING INTO ACCOUNT ALL LOCAL CONDITIONS. NYLOPLAST RECOMMENDS USING A MINIMUM SAFETY FACTOR OF 1.25 FOR PAVED AREAS AND 2.0 FOR TURF AREAS. ADS/NYLOPLAST IS NOT RESPONSIBLE FOR MISUSE OF THIS TOOL. Subdivision:Polestar Project Name:Polestar Location:Fort Collins Project No.: Design Storm:100-Year Calculated By:ARJ Checked By: Date:May-24 Input Type of Grate 12" Drop In Head (ft)0.3 Properties Orifice Flow Area (in)39.75 Orifice Flow Area (ft)0.27 Weir Flow Perimeter (in)33.31 Weir Flow Perimeter (ft)2.78 Solution Capacity (cfs)0.72 Capacity (gpm)324.50 Design Point 100 YR (cfs)14a 4.3 No of inlets 1 Total Cap. (cfs)0.72 FS 0.17 uses the lesser of these two equations REV 2.1.21 39797.01 DISCLAIMER: SAFETY FACTORS ARE NOT INCLUDED IN THESE CALCULATIONS. ACTUAL CALCULATIONS SHOULD BE CARRIED OUT AND VERIFIED BY THE DESIGN ENGINEER TAKING INTO ACCOUNT ALL LOCAL CONDITIONS. NYLOPLAST RECOMMENDS USING A MINIMUM SAFETY FACTOR OF 1.25 FOR PAVED AREAS AND 2.0 FOR TURF AREAS. ADS/NYLOPLAST IS NOT RESPONSIBLE FOR MISUSE OF THIS TOOL. Subdivision:Polestar Project Name:Polestar Location:Fort Collins Project No.: Design Storm:100-Year Calculated By:ARJ Checked By: Date:May-24 Input Type of Grate 18" Drop In Head (ft)0.2 Properties Orifice Flow Area (in)84.61 Orifice Flow Area (ft)0.58 Weir Flow Perimeter (in)48.00 Weir Flow Perimeter (ft)4.00 Solution Capacity (cfs)1.19 Capacity (gpm)534.73 Design Point 100 YR (cfs)15a 4.2 No of inlets 2 Total Cap. (cfs)2.38 FS 0.57 uses the lesser of these two equations REV 2.1.21 39797.01 DISCLAIMER: SAFETY FACTORS ARE NOT INCLUDED IN THESE CALCULATIONS. ACTUAL CALCULATIONS SHOULD BE CARRIED OUT AND VERIFIED BY THE DESIGN ENGINEER TAKING INTO ACCOUNT ALL LOCAL CONDITIONS. NYLOPLAST RECOMMENDS USING A MINIMUM SAFETY FACTOR OF 1.25 FOR PAVED AREAS AND 2.0 FOR TURF AREAS. ADS/NYLOPLAST IS NOT RESPONSIBLE FOR MISUSE OF THIS TOOL. Subdivision:Polestar Project Name:Polestar Location:Fort Collins Project No.: Design Storm:100-Year Calculated By:ARJ Checked By: Date:May-24 Input Type of Grate 12" Drop In Head (ft)0.2 Properties Orifice Flow Area (in)39.75 Orifice Flow Area (ft)0.27 Weir Flow Perimeter (in)33.31 Weir Flow Perimeter (ft)2.78 Solution Capacity (cfs)0.59 Capacity (gpm)264.96 Design Point 100 YR (cfs)16a 4.8 No of inlets 2 Total Cap. (cfs)1.18 FS 0.25 uses the lesser of these two equations REV 2.1.21 39797.01 DISCLAIMER: SAFETY FACTORS ARE NOT INCLUDED IN THESE CALCULATIONS. ACTUAL CALCULATIONS SHOULD BE CARRIED OUT AND VERIFIED BY THE DESIGN ENGINEER TAKING INTO ACCOUNT ALL LOCAL CONDITIONS. NYLOPLAST RECOMMENDS USING A MINIMUM SAFETY FACTOR OF 1.25 FOR PAVED AREAS AND 2.0 FOR TURF AREAS. ADS/NYLOPLAST IS NOT RESPONSIBLE FOR MISUSE OF THIS TOOL. Subdivision:Polestar Project Name:Polestar Location:Fort Collins Project No.: Design Storm:100-Year Calculated By:ARJ Checked By: Date:May-24 Input Type of Grate 18" Drop In Head (ft)0.1 Properties Orifice Flow Area (in)84.61 Orifice Flow Area (ft)0.58 Weir Flow Perimeter (in)48.00 Weir Flow Perimeter (ft)4.00 Solution Capacity (cfs)0.42 Capacity (gpm)189.06 Design Point 100 YR (cfs)17a 6.7 No of inlets 6 Total Cap. (cfs)2.53 FS 0.38 Note: 6 inlets along shallow swale designed to capture flow uses the lesser of these two equations REV 2.1.21 39797.01 DISCLAIMER: SAFETY FACTORS ARE NOT INCLUDED IN THESE CALCULATIONS. ACTUAL CALCULATIONS SHOULD BE CARRIED OUT AND VERIFIED BY THE DESIGN ENGINEER TAKING INTO ACCOUNT ALL LOCAL CONDITIONS. NYLOPLAST RECOMMENDS USING A MINIMUM SAFETY FACTOR OF 1.25 FOR PAVED AREAS AND 2.0 FOR TURF AREAS. ADS/NYLOPLAST IS NOT RESPONSIBLE FOR MISUSE OF THIS TOOL. Subdivision:Polestar Project Name:Polestar Location:Fort Collins Project No.: Design Storm:100-Year Calculated By:ARJ Checked By: Date:May-24 Input Type of Grate 18" Drop In and Trench drain Head (ft)0.1 Trench Drain Properties Inlet Length (ft)133 Orifice Flow Area (in)84.61 Opening (in)5 Orifice Flow Area (ft)0.58 Area - (ft)55.42 Weir Flow Perimeter (in)48.00 Perimeter (ft)266.83 Weir Flow Perimeter (ft)4.00 Capacity 28.10 Solution Capacity (cfs)0.42 Capacity (gpm)189.06 Design Point 100 YR (cfs)18a 5.4 No of inlets + Trench Drain 2 Inlets and 1 Trench drain Total Cap. (cfs)28.94 FS 5.34 Note: Trench drain along shallow swale designed to capture flow Swale is at 0.5% One Small 8" inlet to capture nuisance flows in this basin uses the lesser of these two equations REV 2.1.21 39797.01 DISCLAIMER: SAFETY FACTORS ARE NOT INCLUDED IN THESE CALCULATIONS. ACTUAL CALCULATIONS SHOULD BE CARRIED OUT AND VERIFIED BY THE DESIGN ENGINEER TAKING INTO ACCOUNT ALL LOCAL CONDITIONS. NYLOPLAST RECOMMENDS USING A MINIMUM SAFETY FACTOR OF 1.25 FOR PAVED AREAS AND 2.0 FOR TURF AREAS. ADS/NYLOPLAST IS NOT RESPONSIBLE FOR MISUSE OF THIS TOOL. Subdivision:Polestar Project Name:Polestar Location:Fort Collins Project No.: Design Storm:100-Year Calculated By:ARJ Checked By: Date:May-24 Input Type of Grate 12" Pedestrian Head (ft)0.17 Properties Orifice Flow Area (in)50.6 Orifice Flow Area (ft)0.35 Weir Flow Perimeter (in)43.25 Weir Flow Perimeter (ft)3.60 Solution Capacity (cfs)0.69 Capacity (gpm)310.95 Design Point 100 YR (cfs)19a 2.6 No of inlets 4 Total Cap. (cfs)2.77 FS 1.07 uses the lesser of these two equations REV 2.1.21 39797.01 DISCLAIMER: SAFETY FACTORS ARE NOT INCLUDED IN THESE CALCULATIONS. ACTUAL CALCULATIONS SHOULD BE CARRIED OUT AND VERIFIED BY THE DESIGN ENGINEER TAKING INTO ACCOUNT ALL LOCAL CONDITIONS. NYLOPLAST RECOMMENDS USING A MINIMUM SAFETY FACTOR OF 1.25 FOR PAVED AREAS AND 2.0 FOR TURF AREAS. ADS/NYLOPLAST IS NOT RESPONSIBLE FOR MISUSE OF THIS TOOL. Subdivision:Polestar Project Name:Polestar Location:Fort Collins Project No.: Design Storm:100-Year Calculated By:ARJ Checked By: Date:May-24 Input Type of Grate 24" Dome Head (ft)0.375 Properties Orifice Flow Area (in)265.19 Orifice Flow Area (ft)1.83 Weir Flow Perimeter (in)71.47 Weir Flow Perimeter (ft)5.96 Solution Capacity (cfs)4.55 Capacity (gpm)2044.06 Design Point 100 YR (cfs)2.1 9.0 No of inlets 2 Total Cap. (cfs)9.11 FS 1.01 Note: overflow path directley into pond uses the lesser of these two equations REV 2.1.21 39797.01 DISCLAIMER: SAFETY FACTORS ARE NOT INCLUDED IN THESE CALCULATIONS. ACTUAL CALCULATIONS SHOULD BE CARRIED OUT AND VERIFIED BY THE DESIGN ENGINEER TAKING INTO ACCOUNT ALL LOCAL CONDITIONS. NYLOPLAST RECOMMENDS USING A MINIMUM SAFETY FACTOR OF 1.25 FOR PAVED AREAS AND 2.0 FOR TURF AREAS. ADS/NYLOPLAST IS NOT RESPONSIBLE FOR MISUSE OF THIS TOOL. Subdivision:Polestar Project Name:Polestar Location:Fort Collins Project No.: Design Storm:100-Year Calculated By:ARJ Checked By: Date:May-24 Input Type of Grate 18" Dome Head (ft)0.43 Properties Orifice Flow Area (in)170.74 Orifice Flow Area (ft)1.18 Weir Flow Perimeter (in)53.85 Weir Flow Perimeter (ft)4.49 Solution Capacity (cfs)3.72 Capacity (gpm)1668.75 Design Point 100 YR (cfs)3.1 5.5 No of inlets 2 Total Cap. (cfs)7.44 FS 1.34 Note: overflow path directly into pond uses the lesser of these two equations REV 2.1.21 39797.01 DISCLAIMER: SAFETY FACTORS ARE NOT INCLUDED IN THESE CALCULATIONS. ACTUAL CALCULATIONS SHOULD BE CARRIED OUT AND VERIFIED BY THE DESIGN ENGINEER TAKING INTO ACCOUNT ALL LOCAL CONDITIONS. NYLOPLAST RECOMMENDS USING A MINIMUM SAFETY FACTOR OF 1.25 FOR PAVED AREAS AND 2.0 FOR TURF AREAS. ADS/NYLOPLAST IS NOT RESPONSIBLE FOR MISUSE OF THIS TOOL. Subdivision:Polestar Project Name:Polestar Location:Fort Collins Project No.: Design Storm:100-Year Calculated By:ARJ Checked By: Date:May-24 Input Type of Grate Type C Head (ft)0.20 Properties Orifice Flow Area (in)907.2 Orifice Flow Area (ft)6.30 Weir Flow Perimeter (in)144.00 Weir Flow Perimeter (ft)12.00 Solution Capacity (cfs)3.57 Capacity (gpm)1604.07 Design Point 100 YR (cfs)6d 1.8 No of inlets 1 Total Cap. (cfs)3.57 FS 1.94 Note: using CDOT Type C Inlet uses the lesser of these two equations REV 2.1.21 39797.01 DISCLAIMER: SAFETY FACTORS ARE NOT INCLUDED IN THESE CALCULATIONS. ACTUAL CALCULATIONS SHOULD BE CARRIED OUT AND VERIFIED BY THE DESIGN ENGINEER TAKING INTO ACCOUNT ALL LOCAL CONDITIONS. NYLOPLAST RECOMMENDS USING A MINIMUM SAFETY FACTOR OF 1.25 FOR PAVED AREAS AND 2.0 FOR TURF AREAS. ADS/NYLOPLAST IS NOT RESPONSIBLE FOR MISUSE OF THIS TOOL. Subdivision:Polestar Project Name:Polestar Location:Fort Collins Project No.: Design Storm:100-Year Calculated By:ARJ Checked By: Date:May-24 Input Type of Grate 18" Dome Head (ft)0.25 Properties Orifice Flow Area (in)170.74 Orifice Flow Area (ft)1.18 Weir Flow Perimeter (in)53.85 Weir Flow Perimeter (ft)4.49 Solution Capacity (cfs)1.87 Capacity (gpm)838.32 Design Point 100 YR (cfs)4.1 4.8 No of inlets 4 Total Cap. (cfs)7.47 FS 1.56 uses the lesser of these two equations REV 2.1.21 39797.01 DISCLAIMER: SAFETY FACTORS ARE NOT INCLUDED IN THESE CALCULATIONS. ACTUAL CALCULATIONS SHOULD BE CARRIED OUT AND VERIFIED BY THE DESIGN ENGINEER TAKING INTO ACCOUNT ALL LOCAL CONDITIONS. NYLOPLAST RECOMMENDS USING A MINIMUM SAFETY FACTOR OF 1.25 FOR PAVED AREAS AND 2.0 FOR TURF AREAS. ADS/NYLOPLAST IS NOT RESPONSIBLE FOR MISUSE OF THIS TOOL. Subdivision:Polestar Project Name:Polestar Location:Fort Collins Project No.: Design Storm:100-Year Calculated By:ARJ Checked By: Date:May-24 Input Type of Grate Type C Head (ft)0.5 Properties Orifice Flow Area (in)907.2 Orifice Flow Area (ft)6.30 Weir Flow Perimeter (in)144.00 Weir Flow Perimeter (ft)12.00 Solution Capacity (cfs)14.13 Capacity (gpm)6340.64 Design Point 100 YR (cfs)4d 3.6 No of inlets 1 Total Cap. (cfs)14.13 FS 3.89 Note: using CDOT Type C Inlet uses the lesser of these two equations REV 2.1.21 39797.01 DISCLAIMER: SAFETY FACTORS ARE NOT INCLUDED IN THESE CALCULATIONS. ACTUAL CALCULATIONS SHOULD BE CARRIED OUT AND VERIFIED BY THE DESIGN ENGINEER TAKING INTO ACCOUNT ALL LOCAL CONDITIONS. NYLOPLAST RECOMMENDS USING A MINIMUM SAFETY FACTOR OF 1.25 FOR PAVED AREAS AND 2.0 FOR TURF AREAS. ADS/NYLOPLAST IS NOT RESPONSIBLE FOR MISUSE OF THIS TOOL. Project: Inlet ID: Gutter Geometry: Maximum Allowable Width for Spread Behind Curb TBACK =13.0 ft BACK 0.020 ft/ft BACK 0.016 CURB 6.00 inches CROWN 16.0 ft Gutter Width W =2.00 ft X 0.020 ft/ft W 0.083 ft/ft O 0.000 ft/ft STREET 0.016 Minor Storm Major Storm MAX 5.0 16.0 MAX 6.0 12.0 Check boxes are not applicable in SUMP conditions MINOR STORM Allowable Capacity is not applicable to Sump Condition Minor Storm Major Storm Qallow =SUMP SUMP cfs MHFD-Inlet, Version 5.03 (August 2023) ALLOWABLE CAPACITY FOR ONE-HALF OF STREET (Minor & Major Storm) (Based on Regulated Criteria for Maximum Allowable Flow Depth and Spread) MHFD-Inlet_v5.03.xlsm, Inlet DP 6a 11/25/2024, 11:02 AM Design Information (Input)MINOR MAJOR Type of Inlet Type = local Number of Unit Inlets (Grate or Curb Opening)No =6 6 Water Depth at Flowline (outside of local depression)Ponding Depth =5.0 7.3 inches Grate Information MINOR MAJOR o o ratio f w o Curb Opening Information MINOR MAJOR o vert throat p f w o (C) =0.67 0.67 Low Head Performance Reduction (Calculated)MINOR MAJOR Depth for Grate Midwidth Grate 0.42 0.61 ft Depth for Curb Opening Weir Equation Curb 0.25 0.44 ft Grate Curb Opening Performance Reduction Factor for Long Inlets Curb N/A N/A Combination Inlet Performance Reduction Factor for Long Inlets Combination 0.47 0.69 MINOR MAJOR Total Inlet Interception Capacity (assumes clogged condition)Qa =8.8 25.8 cfs Inlet Capacity IS GOOD for Minor and Major Storms (>Q Peak)Q PEAK REQUIRED =5.2 23.5 cfs INLET IN A SUMP OR SAG LOCATION MHFD-Inlet, Version 5.03 (August 2023) User-Defined Combination H-VertH-Curb W Lo (C) Lo (G) Wo WP User-Defined Combination Override Depths City of Fort Collins Criteria Cw= 3.0 Co = 0.67 MHFD-Inlet_v5.03.xlsm, Inlet DP 6a 11/25/2024, 11:02 AM Project: Inlet ID: Gutter Geometry: Maximum Allowable Width for Spread Behind Curb TBACK =13.0 ft Side Slope Behind Curb (leave blank for no conveyance credit behind curb)SBACK =0.020 ft/ft Manning's Roughness Behind Curb (typically between 0.012 and 0.020)nBACK =0.016 Height of Curb at Gutter Flow Line HCURB =6.00 inches Distance from Curb Face to Street Crown TCROWN =18.0 ft Gutter Width W =2.00 ft Street Transverse Slope SX =0.020 ft/ft Gutter Cross Slope (typically 2 inches over 24 inches or 0.083 ft/ft)SW =0.083 ft/ft Street Longitudinal Slope - Enter 0 for sump condition SO =0.000 ft/ft Manning's Roughness for Street Section (typically between 0.012 and 0.020)nSTREET =0.016 Minor Storm Major Storm Max. Allowable Spread for Minor & Major Storm TMAX =16.0 16.0 ft Max. Allowable Depth at Gutter Flowline for Minor & Major Storm dMAX =6.0 12.0 inches Check boxes are not applicable in SUMP conditions MINOR STORM Allowable Capacity is not applicable to Sump Condition Minor Storm Major Storm MAJOR STORM Allowable Capacity is not applicable to Sump Condition Qallow =SUMP SUMP cfs MHFD-Inlet, Version 5.03 (August 2023) ALLOWABLE CAPACITY FOR ONE-HALF OF STREET (Minor & Major Storm) (Based on Regulated Criteria for Maximum Allowable Flow Depth and Spread) MHFD-Inlet_v5.03.xlsm, Inlet DP 7a 11/13/2024, 1:17 PM Design Information (Input)MINOR MAJOR Type of Inlet Type = Local Depression (additional to continuous gutter depression 'a' from above)alocal =2.00 2.00 inches Number of Unit Inlets (Grate or Curb Opening)No =2 2 Water Depth at Flowline (outside of local depression)Ponding Depth =5.4 5.5 inches Grate Information MINOR MAJOR Length of a Unit Grate Lo (G) =3.00 3.00 feet Width of a Unit Grate Wo =2.00 2.00 feet Open Area Ratio for a Grate (typical values 0.15-0.90)Aratio =0.31 0.31 Clogging Factor for a Single Grate (typical value 0.50 - 0.70)Cf (G) =0.50 0.50 Grate Weir Coefficient (typical value 2.15 - 3.60)Cw (G) =3.00 3.00 Grate Orifice Coefficient (typical value 0.60 - 0.80)Co (G) =0.67 0.67 Curb Opening Information MINOR MAJOR Length of a Unit Curb Opening Lo (C) =3.00 3.00 feet Height of Vertical Curb Opening in Inches Hvert =6.00 6.00 inches Height of Curb Orifice Throat in Inches Hthroat =6.00 6.00 inches Angle of Throat Theta =0.00 0.00 degrees Side Width for Depression Pan (typically the gutter width of 2 feet)Wp =2.00 2.00 feet Clogging Factor for a Single Curb Opening (typical value 0.10)Cf (C) =0.10 0.10 Curb Opening Weir Coefficient (typical value 2.3-3.7)Cw (C) =3.00 3.00 Curb Opening Orifice Coefficient (typical value 0.60 - 0.70)Co (C) =0.67 0.67 Low Head Performance Reduction (Calculated)MINOR MAJOR Depth for Grate Midwidth d =0.45 0.46 ft Depth for Curb Opening Weir Equation d =0.28 0.29 ft Grated Inlet Performance Reduction Factor for Long Inlets RF =0.63 0.65 Curb Opening Performance Reduction Factor for Long Inlets RF =N/A N/A Combination Inlet Performance Reduction Factor for Long Inlets RF =0.63 0.65 MINOR MAJOR Total Inlet Interception Capacity (assumes clogged condition)Qa =5.0 5.5 cfs Inlet Capacity IS GOOD for Minor and Major Storms (>Q Peak)Q PEAK REQUIRED =1.1 5.1 cfs User-Defined Combination INLET IN A SUMP OR SAG LOCATION MHFD-Inlet, Version 5.03 (August 2023) H-VertH-Curb W Lo (C) Lo (G) Wo WP User-Defined Combination Override Depths City of Fort Collins Criteria Cw= 3.0 Co = 0.67 MHFD-Inlet_v5.03.xlsm, Inlet DP 7a 11/13/2024, 1:17 PM Project: Inlet ID: Gutter Geometry: Maximum Allowable Width for Spread Behind Curb TBACK =13.5 ft Side Slope Behind Curb (leave blank for no conveyance credit behind curb)SBACK =0.020 ft/ft Manning's Roughness Behind Curb (typically between 0.012 and 0.020)nBACK =0.016 Height of Curb at Gutter Flow Line HCURB =6.00 inches Distance from Curb Face to Street Crown TCROWN =22.0 ft Gutter Width W =2.00 ft Street Transverse Slope SX =0.020 ft/ft Gutter Cross Slope (typically 2 inches over 24 inches or 0.083 ft/ft)SW =0.083 ft/ft Street Longitudinal Slope - Enter 0 for sump condition SO =0.014 ft/ft Manning's Roughness for Street Section (typically between 0.012 and 0.020)nSTREET =0.016 Minor Storm Major Storm Max. Allowable Spread for Minor & Major Storm TMAX =18.0 18.0 ft Max. Allowable Depth at Gutter Flowline for Minor & Major Storm dMAX =6.0 12.0 inches Allow Flow Depth at Street Crown (check box for yes, leave blank for no) MINOR STORM Allowable Capacity is based on Spread Criterion Minor Storm Major Storm MAJOR STORM Allowable Capacity is based on Spread Criterion Qallow =14.8 14.8 cfs Minor storm max. allowable capacity GOOD - greater than the design peak flow of 0.02 cfs on sheet 'Inlet Management' MHFD-Inlet, Version 5.03 (August 2023) ALLOWABLE CAPACITY FOR ONE-HALF OF STREET (Minor & Major Storm) (Based on Regulated Criteria for Maximum Allowable Flow Depth and Spread) MHFD-Inlet_v5.03.xlsm, Inlet DP 3e 11/13/2024, 1:17 PM Design Information (Input)MINOR MAJOR Type of Inlet Type = Local Depression (additional to continuous gutter depression 'a')aLOCAL =2.0 2.0 inches Total Number of Units in the Inlet (Grate or Curb Opening)No =2 2 Length of a Single Unit Inlet (Grate or Curb Opening)Lo =3.00 3.00 ft Width of a Unit Grate (cannot be greater than W, Gutter Width)Wo =2.00 2.00 ft Clogging Factor for a Single Unit Grate (typical min. value = 0.5)Cf (G) =0.50 0.50 Clogging Factor for a Single Unit Curb Opening (typical min. value = 0.1)Cf (C) =0.10 0.10 Street Hydraulics: OK - Q < Allowable Street Capacity'MINOR MAJOR Design Discharge for Half of Street (from Inlet Management)Qo =0.0 1.5 cfs Water Spread Width T =0.7 6.3 ft Water Depth at Flowline (outside of local depression)d =1.7 3.0 inches Water Depth at Street Crown (or at TMAX)dCROWN =0.0 0.0 inches Ratio of Gutter Flow to Design Flow Eo =1.000 0.797 Discharge outside the Gutter Section W, carried in Section Tx Qx =0.0 0.3 cfs Discharge within the Gutter Section W Qw =0.0 1.2 cfs Discharge Behind the Curb Face QBACK =0.0 0.0 cfs Flow Area within the Gutter Section W AW =0.00 0.34 sq ft Velocity within the Gutter Section W VW =0.0 3.5 fps Water Depth for Design Condition dLOCAL =3.7 5.0 inches Analysis For Grate Type = CDOT/Denver 13 Valley Grate (Calculated)MINOR MAJOR Total Length of Inlet Grate Opening L =6.00 6.00 ft Ratio of Grate Flow to Design Flow Eo-GRATE =1.000 0.797 Under No-Clogging Condition MINOR MAJOR Minimum Velocity Where Grate Splash-Over Begins Vo =2.42 2.42 fps Interception Rate of Frontal Flow Rf =1.00 0.96 Interception Rate of Side Flow Rx =0.86 0.55 Interception Capacity Qi =0.0 1.3 cfs Under Clogging Condition MINOR MAJOR Clogging Coefficient for Multiple-unit Grate Inlet GrateCoeff =1.50 1.50 Clogging Factor for Multiple-unit Grate Inlet GrateClog =0.38 0.38 Effective (unclogged) Length of Multiple-unit Grate Inlet Le =3.75 3.75 ft Minimum Velocity Where Grate Splash-Over Begins Vo =1.83 1.83 fps Interception Rate of Frontal Flow Rf =1.00 0.91 Interception Rate of Side Flow Rx =0.67 0.30 Actual Interception Capacity Qa =0.0 1.2 cfs Carry-Over Flow = Qo-Qa (to be applied to curb opening or next d/s inlet)Qb =0.0 0.3 cfs Curb Opening or Slotted Inlet Analysis (Calculated)MINOR MAJOR Equivalent Slope Se Se =0.166 0.137 ft/ft Required Length LT to Have 100% Interception LT =0.00 2.80 ft Under No-Clogging Condition MINOR MAJOR Effective Length of Curb Opening or Slotted Inlet (minimum of L, LT)L =0.00 2.80 ft Interception Capacity Qi =0.0 0.2 cfs Under Clogging Condition MINOR MAJOR Clogging Coefficient CurbCoeff =0.00 1.00 Clogging Factor for Multiple-unit Curb Opening or Slotted Inlet CurbClog =0.00 0.08 Effective (Unclogged) Length Le =0.00 2.80 ft Actual Interception Capacity Qa =0.0 0.2 cfs Carry-Over Flow = Qb(GRATE)-Qa Qb =0.0 0.1 cfs Summary MINOR MAJOR Total Inlet Interception Capacity Q =0.0 1.4 cfs Total Inlet Carry-Over Flow (flow bypassing inlet)Qb =0.0 0.1 cfs Capture Percentage = Qa/Qo C% =100 92 % INLET ON A CONTINUOUS GRADE MHFD-Inlet, Version 5.03 (August 2023) User-Defined CombinationUser-Defined Combination MHFD-Inlet_v5.03.xlsm, Inlet DP 3e 11/13/2024, 1:17 PM Street Section at Neck down in Polaris Street Total Flow into the Street is Approx. is 23.5 cfs at dp 6a and 5.1 cfs at 7a. 38.38 cfs Capacity to ROW. Orchard Place - Flow Lines – 100 year event Overflow Swale – Cross Section South of W. Orchard Place Urban Drainage and Flood Control District Modeling Hydraulic and Energy Gradients in Storm Sewers: October 6, 2009 Page 19 6.3 Combined Junction Loss Equation g Vkg Vkg Vkg V g VkHH ofi bL fi m fofT bTsj 22222 22222 Equation (13) where,Hj = UD Sewer junction loss Hs = Standard method junction loss kbT = Bend loss coefficient at truckling kbL = Bend loss coefficient at lateral VfT = Full flow velocity of trunk line at manhole Vfi = Full flow velocity of incoming lateral at manhole Vo = Full flow velocity of trunk line at manhole k =Head Loss Coefficient g =Acceleration due to Gravity Table 2 StormCAD Standard Method Conversions StormCAD Conversion Table Be n d L o s s Bend Angle K coefficient Conversion 0 0.05 22.5 0.1 45 0.4 60 0.64 90 1.32 La t e r a l L o s s 1 Lateral K coefficient Conversion Bend Angle Non Surcharged Surcharged 45 0.27 0.47 60 0.52 0.9 90 1.02 1.77 2 Laterals K coefficient Conversion 45 0.96 60 1.16 90 1.52 The engineering guidelines from this study provide the methodology needed to reach an HGL analysis result using StormCAD which replicates that of UD-Sewer. However, the following limitations apply: The full pipe velocity should not exceed 18 fps The conversion only applies for the storm sewer pipe sizes 42” or less A regional storm sewer system should use UD-Sewer only Scenario: 100 - Year C-5 .1 (Sto rm) O-3 O-5 O-6 O-2 O-1 6.3 - G RATE INLET 3.3 - Type C I nlet (Storm) 3.2 MH (Storm) C - 2.2 T ype D I nlet 1B - GRATE INLET (Storm) 3.4 - T ype C I nlet (St orm) 1.3 - Shallow T op MH (Storm) 6.2 MH (Storm) 2.2 GRAT E INLET (Storm) 1.4 - MH (Storm) 1.5 MH (Storm) 1.6 MH (Storm) 1.2A - Type C Inlet 1.7 - MH (Storm) 1.3A - 12" DROP I N NYLOPLAST IC I NLET 1.8 - MH (Storm) 1.9 - MH (Storm) 1.10 - T ype C I nlet 5.2 - O UT LET ST RUT URE (St orm) 2.3 - 18 INCH DOME INLET (St orm) Page 1 of 127 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203- 755-1666 8/28/2024 StormCAD [10.03.02.04]Bentley Systems, Inc. Haestad Methods Solution Center3979701 StormCAD Model.stsw 100 Year Profiles 100 Year Profiles 100 Year Profiles 100 Year Profiles Scenario: 100 - Year Current Time Step: 0.000 h FlexTable: Conduit Table X:\3970000.all\3979701\StormCAD\3979701 StormCAD Model.stsw Upstream Structure Label Flow (cfs) Diameter (in) Length (Unified) (ft) Slope (Calculated) (ft/ft) Invert (Start) (ft) Invert (Stop) (ft) Hydraulic Grade Line (In) (ft) Hydraulic Grade Line (Out) (ft) Energy Grade Line (In) (ft) Energy Grade Line (Out) (ft) Velocity (ft/s) 3.3 - Type C Inlet (Storm)C - 3.2 (Storm)9.20 18.0 75.2 0.005 5,104.96 5,104.56 5,107.22 5,106.65 5,107.64 5,107.07 5.21 Page 1 of 1 11/25/2024file:///C:/Users/WaterR/AppData/Local/Temp/Bentley/StormCAD/aunfcuv2.xml Scenario: 100 - Year Current Time Step: 0.000 h FlexTable: Manhole Table X:\3970000.all\3979701\StormCAD\3979701 StormCAD Model.stsw Label Elevation (Ground) (ft) Elevation (Invert) (ft) Flow (Total Out) (cfs) Hydraulic Grade Line (In) (ft) Hydraulic Grade Line (Out) (ft) Energy Grade Line (In) (ft) Energy Grade Line (Out) (ft) Headloss Method Headloss (ft) Headloss Coefficient (Standard) 1.3A - 12" DROP IN NYLOPLASTIC INLET 5,114.42 5,112.11 3.50 5,112.93 5,112.91 5,113.35 5,113.33 Standard 0.02 0.050 1.4 - MH (Storm)5,110.91 5,106.86 15.60 5,109.90 5,109.86 5,110.28 5,110.25 Standard 0.04 0.100 1.3 - Shallow Top MH (Storm)5,110.31 5,106.34 17.50 5,109.46 5,108.73 5,109.59 5,109.21 Standard 0.73 1.520 3.3 - Type C Inlet (Storm)5,108.86 5,104.96 9.20 5,107.24 5,107.22 5,107.58 5,107.64 Standard 0.02 0.050 Page 1 of 1 11/25/2024file:///C:/Users/WaterR/AppData/Local/Temp/Bentley/StormCAD/snxrq4cw.xml 2 Year Profiles 2 Year Profiles 2 Year Profiles 2 Year Profiles Scenario: 2 - Year Current Time Step: 0.000 h FlexTable: Conduit Table X:\3970000.all\3979701\StormCAD\3979701 StormCAD Model.stsw Upstream Structure Label Flow (cfs) Diameter (in) Length (Unified) (ft) Slope (Calculated) (ft/ft) Invert (Start) (ft) Invert (Stop) (ft) Hydraulic Grade Line (In) (ft) Hydraulic Grade Line (Out) (ft) Energy Grade Line (In) (ft) Energy Grade Line (Out) (ft) Velocity (ft/s) 3.3 - Type C Inlet (Storm)C - 3.2 (Storm)2.00 18.0 75.2 0.005 5,104.96 5,104.56 5,105.49 5,105.09 5,105.69 5,105.29 3.63 Page 1 of 1 11/25/2024file:///C:/Users/WaterR/AppData/Local/Temp/Bentley/StormCAD/3nhbi2xw.xml Scenario: 2 - Year Current Time Step: 0.000 h FlexTable: Manhole Table X:\3970000.all\3979701\StormCAD\3979701 StormCAD Model.stsw Label Elevation (Ground) (ft) Elevation (Invert) (ft) Flow (Total Out) (cfs) Hydraulic Grade Line (In) (ft) Hydraulic Grade Line (Out) (ft) Energy Grade Line (In) (ft) Energy Grade Line (Out) (ft) Headloss Method Headloss (ft) Headloss Coefficient (Standard) 1.3A - 12" DROP IN NYLOPLASTIC INLET 5,114.42 5,112.11 0.80 5,112.49 5,112.49 5,112.63 5,112.62 Standard 0.01 0.050 1.4 - MH (Storm)5,110.91 5,106.86 3.50 5,107.54 5,107.51 5,107.80 5,107.75 Standard 0.02 0.100 1.3 - Shallow Top MH (Storm)5,110.31 5,106.34 3.90 5,107.42 5,107.22 5,107.44 5,107.36 Standard 0.20 1.520 3.3 - Type C Inlet (Storm)5,108.86 5,104.96 2.00 5,105.50 5,105.49 5,105.69 5,105.69 Standard 0.01 0.050 Page 1 of 1 11/25/2024file:///C:/Users/WaterR/AppData/Local/Temp/Bentley/StormCAD/yvuzyrmk.xml 21 APPENDIX D – WATER QUALITY CALCULATIONS Subdivision:Polestar Project Name:Polestar Location:Fort Collins Project No.:39797.01 Calculated By:ARJ Checked By:0 Date:11/13/24 Basin (ac)% Imp. A1 1.02 15.8% A2 0.58 51.6% A3 0.78 25.3% A4 1.23 65.0% A5 0.42 56.5% A6 1.03 68.7% A13 0.40 61.0% A15 0.49 23.5% A16 0.12 51.1% A17 0.43 29.6% A18 0.72 45.8% A19 0.35 51.5% Total 9.75 50.3% WQCV Drain Time (hr):12 Coefficient, a (Figure 3.2):0.8 WQCV (in):0.17 WQCV (ac-ft):0.13 WQ Tributary Areas #1 - Rain Garden X:\3970000.all\3979701\Excel\Drainage\3979701 Drainage_Calcs_Template_v2.07.xlsm Page 1 of 8 2/10/2025 Subdivision:Polestar Project Name:Polestar Location:Fort Collins Project No.:39797.01 Calculated By:ARJ Checked By:0 Date:11/13/24 Basin (ac)% Imp. B1 1.23 49.8% B2 0.31 77.7% Total 1.55 55.5% WQCV Drain Time (hr):12 Coefficient, a (Figure 3.2):0.8 WQCV (in):0.18 WQCV (ac-ft):0.02 WQ Tributary Areas # 2- Rain Garden X:\3970000.all\3979701\Excel\Drainage\3979701 Drainage_Calcs_Template_v2.07.xlsm Page 2 of 8 2/10/2025 Subdivision:Polestar Project Name:Polestar Location:Fort Collins Project No.:39797.01 Calculated By:ARJ Checked By:0 Date:11/13/24 Basin (ac)% Imp. C1 0.28 47.0% C2 0.32 30.5% D8 0.19 90.5% D7 0.11 85.5% Total 0.90 55.0% WQCV Drain Time (hr):12 Coefficient, a (Figure 3.2):0.8 WQCV (in):0.18 WQCV (ac-ft):0.01 WQ Tributary Areas # 3 - Rain Garden X:\3970000.all\3979701\Excel\Drainage\3979701 Drainage_Calcs_Template_v2.07.xlsm Page 3 of 8 2/10/2025 Subdivision:Polestar Project Name:Polestar Location:Fort Collins Project No.:39797.01 Calculated By:ARJ Checked By:0 Date:11/13/24 Basin (ac)% Imp. D6 0.28 60.5% Total 0.28 60.5% WQCV Drain Time (hr):12 Coefficient, a (Figure 3.2):0.8 WQCV (in):0.19 WQCV (ac-ft):0.004 WQ Tributary Areas # 4 - Rain Garden X:\3970000.all\3979701\Excel\Drainage\3979701 Drainage_Calcs_Template_v2.07.xlsm Page 4 of 8 2/10/2025 Subdivision:Polestar Project Name:Polestar Location:Fort Collins Project No.:39797.01 Calculated By:ARJ Checked By:0 Date:11/13/24 Basin (ac)% Imp. D5 0.29 67.3% D4 0.25 60.9% Total 0.54 64.3% WQCV Drain Time (hr):12 Coefficient, a (Figure 3.2):0.8 WQCV (in):0.20 WQCV (ac-ft):0.01 WQ Tributary Areas # 5 - Rain Garden X:\3970000.all\3979701\Excel\Drainage\3979701 Drainage_Calcs_Template_v2.07.xlsm Page 5 of 8 2/10/2025 Subdivision:Polestar Project Name:Polestar Location:Fort Collins Project No.:39797.01 Calculated By:ARJ Checked By:0 Date:11/13/24 Basin (ac)% Imp. D3 0.16 69.8% D2 0.22 62.9% D1 0.35 64.1% Total 0.73 65.0% WQCV Drain Time (hr):12 Coefficient, a (Figure 3.2):0.8 WQCV (in):0.20 WQCV (ac-ft):0.01 WQ Tributary Areas # 6 - Rain Garden X:\3970000.all\3979701\Excel\Drainage\3979701 Drainage_Calcs_Template_v2.07.xlsm Page 6 of 8 2/10/2025 X:\3970000.all\3979701\Excel\Drainage\3979701 Drainage_Calcs_Template_v2.07.xlsm Page 7 of 8 2/10/2025 Subdivision:Polestar Project Name:Polestar Location:Fort Collins Project No.:39797.01 Calculated By:ARJ Checked By:0 Date:11/13/24 Basin (ac)% Imp. F1 3.92 31.2% E1 2.24 41.1% E2 0.54 54.2% E3 0.31 59.0% OS1 0.61 15.2% OS2 0.09 50.8% 17W 10.20 45.0% Total 17.92 41.0% WQCV Drain Time (hr):40 Coefficient, a (Figure 3.2):1.0 WQCV (in):0.18 WQCV (ac-ft):0.33 WQ Pond Tributary Areas WATER QUALITY IN DETENTION POND This table shows the WQ on-site treated in the Polestar Detention pond. This calculation includes 20% contingency for sediment accumulation as shown in equaltion 7-2. PLEASE NOTE area on MHFD sheet was multiplied by 1.2 to account for this. X:\3970000.all\3979701\Excel\Drainage\3979701 Drainage_Calcs_Template_v2.07.xlsm Page 8 of 8 2/10/2025 Project: Basin ID: Depth Increment =0.50 ft Watershed Information Media Surface --0.00 ------3,022 0.069 Selected BMP Type =RG --0.50 ------3,962 0.091 1,746 0.040 Watershed Area =9.75 acres --1.00 ------5,067 0.116 4,003 0.092 Watershed Length =750 ft --1.50 ------5,855 0.134 6,734 0.155 Watershed Length to Centroid =450 ft --2.00 ------6,658 0.153 9,862 0.226 Watershed Slope =0.010 ft/ft --2.50 ------7,637 0.175 13,436 0.308 Watershed Imperviousness =50.30%percent --3.00 ------8,660 0.199 17,510 0.402 Percentage Hydrologic Soil Group A =0.0%percent --3.50 ------9,728 0.223 22,107 0.508 Percentage Hydrologic Soil Group B =10.0%percent --4.00 ------10,840 0.249 27,249 0.626 Percentage Hydrologic Soil Groups C/D =90.0%percent --4.50 ------12,108 0.278 32,986 0.757 Target WQCV Drain Time =12.0 hours -------- Location for 1-hr Rainfall Depths = User Input -------- -------- -------- Optional User Overrides -------- Water Quality Capture Volume (WQCV) =0.135 acre-feet acre-feet -------- Excess Urban Runoff Volume (EURV) =0.470 acre-feet acre-feet -------- 2-yr Runoff Volume (P1 = 0.82 in.) =0.296 acre-feet 0.82 inches -------- 5-yr Runoff Volume (P1 = 1.09 in.) =0.444 acre-feet inches -------- 10-yr Runoff Volume (P1 = 1.4 in.) =0.665 acre-feet 1.40 inches -------- 25-yr Runoff Volume (P1 = 1.69 in.) =0.933 acre-feet inches -------- 50-yr Runoff Volume (P1 = 1.99 in.) =1.174 acre-feet inches -------- 100-yr Runoff Volume (P1 = 2.86 in.) =1.928 acre-feet 2.86 inches -------- 500-yr Runoff Volume (P1 = 3.14 in.) =2.163 acre-feet inches -------- Approximate 2-yr Detention Volume =0.281 acre-feet -------- Approximate 5-yr Detention Volume =0.438 acre-feet -------- Approximate 10-yr Detention Volume =0.558 acre-feet -------- Approximate 25-yr Detention Volume =0.638 acre-feet -------- Approximate 50-yr Detention Volume =0.693 acre-feet -------- Approximate 100-yr Detention Volume =1.008 acre-feet -------- -------- Define Zones and Basin Geometry -------- Zone 1 Volume (WQCV) =0.135 acre-feet -------- Zone 2 Volume (User Defined - Zone 1) =0.000 acre-feet -------- 0.000 acre-feet -------- Total Detention Basin Volume =0.135 acre-feet -------- Initial Surcharge Volume (ISV) =N/A ft 3 -------- Initial Surcharge Depth (ISD) =N/A ft -------- Total Available Detention Depth (Htotal) =user ft -------- Depth of Trickle Channel (HTC) =N/A ft -------- Slope of Trickle Channel (STC) =N/A ft/ft -------- Slopes of Main Basin Sides (Smain) =user H:V -------- 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 -------- DETENTION BASIN STAGE-STORAGE TABLE BUILDER Override Area (ft 2) Length (ft) Override Stage (ft) Stage (ft) Stage - Storage Description Area (ft 2) Width (ft) Polestar Rain Garden #1 MHFD-Detention, Version 4.06 (July 2022) Volume (ft 3) Volume (ac-ft) Area (acre) Total detention volume is less than 100-year volume. After providing required inputs above including 1-hour rainfall depths, click 'Run CUHP' to generate runoff hydrographs using the embedded Colorado Urban Hydrograph Procedure. Example Zone Configuration (Retention Pond) MHFD-Detention_v4-06 - Rain Garden.xlsm, Basin 11/25/2024, 10:52 AM 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 1.35 Zone 1 (WQCV)1.35 Zone 1 (WQCV) 1.35 Zone 2 (User)1.35 Zone 1 (WQCV) 1.35 Zone 3 (User)1.35 Zone 1 (WQCV) DETENTION BASIN STAGE-STORAGE TABLE BUILDER MHFD-Detention, Version 4.06 (July 2022) 0.000 0.190 0.380 0.570 0.760 0.000 0.070 0.140 0.210 0.280 0.00 1.50 3.00 4.50 6.00 Vo l u m e ( a c - f t ) Ar e a ( a c r e s ) Stage (ft.) Area (acres)Volume (ac-ft) 0 3100 6200 9300 12400 0 5 10 15 20 0.00 1.50 3.00 4.50 6.00 Ar e a ( s q . f t . ) Le n g t h , W i d t h ( f t . ) Stage (ft) Length (ft)Width (ft)Area (sq.ft.) MHFD-Detention_v4-06 - Rain Garden.xlsm, Basin 11/25/2024, 10:52 AM Project: Basin ID: Estimated Estimated Stage (ft)Volume (ac-ft)Outlet Type Zone 1 (WQCV)1.35 0.135 Filtration Media Zone 2 (User)1.35 0.000 Weir&Pipe (Restrict) Zone 3 (User)1.35 0.000 Weir&Pipe (Restrict) Total (all zones)0.135 User Input: Orifice at Underdrain Outlet (typically used to drain WQCV in a Filtration BMP)Calculated Parameters for Underdrain Underdrain Orifice Invert Depth =2.30 ft (distance below the filtration media surface)Underdrain Orifice Area =0.0 ft2 Underdrain Orifice Diameter =1.75 inches Underdrain Orifice Centroid =0.07 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 Centroid of Lowest Orifice =N/A ft (relative to basin bottom at Stage = 0 ft)WQ Orifice Area per Row =N/A ft2 Depth at top of Zone using Orifice Plate =N/A 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 =N/A sq. inches Elliptical Slot Area =N/A ft2 User Input: Stage and Total Area of Each Orifice Row (numbered from lowest to highest) Row 1 (optional)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)N/A N/A N/A N/A N/A N/A N/A N/A Orifice Area (sq. inches)N/A N/A N/A N/A N/A N/A N/A N/A 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)N/A N/A N/A N/A N/A N/A N/A N/A Orifice Area (sq. inches)N/A N/A N/A N/A N/A N/A N/A N/A User Input: Vertical Orifice (Circular or Rectangular)Calculated Parameters for Vertical Orifice Not Selected Not Selected Not Selected Not Selected Invert of Vertical Orifice =N/A N/A ft (relative to basin bottom at Stage = 0 ft)Vertical Orifice Area =N/A N/A ft2 Depth at top of Zone using Vertical Orifice =N/A N/A ft (relative to basin bottom at Stage = 0 ft)Vertical Orifice Centroid =N/A N/A feet Vertical Orifice Diameter =N/A 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 2 Weir Zone 3 Weir Zone 2 Weir Zone 3 Weir Overflow Weir Front Edge Height, Ho =1.36 2.13 ft (relative to basin bottom at Stage = 0 ft)Height of Grate Upper Edge, Ht =1.36 2.86 feet Overflow Weir Front Edge Length =3.140 4.13 feet Overflow Weir Slope Length =0.00 3.01 feet Overflow Weir Grate Slope =0.00 4.00 H:V Grate Open Area / 100-yr Orifice Area =0.00 2.00 Horiz. Length of Weir Sides =0.00 2.92 feet Overflow Grate Open Area w/o Debris =0.00 9.81 ft2 Overflow Grate Type = Close Mesh Grate Close Mesh Grate Overflow Grate Open Area w/ Debris =0.00 9.81 ft2 Debris Clogging % =0%0%% 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 2 Restrictor Zone 3 Restrictor Zone 2 Restrictor Zone 3 Restrictor Depth to Invert of Outlet Pipe =0.08 0.14 ft (distance below basin bottom at Stage = 0 ft)Outlet Orifice Area =0.79 4.91 ft2 Outlet Pipe Diameter =12.00 30.00 inches Outlet Orifice Centroid =0.50 1.25 feet Restrictor Plate Height Above Pipe Invert =12.00 30.00 inches Half-Central Angle of Restrictor Plate on Pipe =3.14 3.14 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 #N/A 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 1.09 1.40 1.69 1.99 2.86 3.14 CUHP Runoff Volume (acre-ft) =0.135 0.470 0.296 0.444 0.665 0.933 1.174 1.928 2.163 Inflow Hydrograph Volume (acre-ft) =N/A N/A 0.296 0.444 0.665 0.933 1.174 1.928 2.163 CUHP Predevelopment Peak Q (cfs) =N/A N/A 0.1 0.8 2.8 6.1 8.4 16.0 18.3 OPTIONAL Override Predevelopment Peak Q (cfs) =N/A N/A Predevelopment Unit Peak Flow, q (cfs/acre) =N/A N/A 0.01 0.08 0.29 0.63 0.87 1.65 1.88 Peak Inflow Q (cfs) =N/A N/A 4.4 6.7 10.2 14.7 18.6 30.4 34.0 Peak Outflow Q (cfs) =0.2 19.3 1.6 3.4 5.2 10.4 14.2 26.3 29.9 Ratio Peak Outflow to Predevelopment Q =N/A N/A N/A 4.5 1.9 1.7 1.7 1.6 1.6 Structure Controlling Flow =Overflow Weir 1 Overflow Weir 2 Overflow Weir 1 Overflow Weir 1 Overflow Weir 2 Overflow Weir 2 Overflow Weir 2 Overflow Weir 2 Overflow Weir 2 Max Velocity through Grate 1 (fps) =N/A N/A N/A N/A N/A N/A N/A N/A N/A Max Velocity through Grate 2 (fps) =N/A 2.37 N/A N/A 0.0 0.5 0.8 2.0 2.4 Time to Drain 97% of Inflow Volume (hours) =12 12 14 14 13 13 12 10 9 Time to Drain 99% of Inflow Volume (hours) =12 13 15 15 15 14 14 14 13 Maximum Ponding Depth (ft) =1.36 3.33 1.64 1.85 2.20 2.63 2.81 3.23 3.34 Area at Maximum Ponding Depth (acres) =0.13 0.21 0.14 0.15 0.16 0.18 0.19 0.21 0.21 Maximum Volume Stored (acre-ft) =0.136 0.470 0.174 0.202 0.256 0.332 0.365 0.449 0.470 DETENTION BASIN OUTLET STRUCTURE DESIGN MHFD-Detention, Version 4.06 (July 2022) Polestar Rain Garden #1 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) MHFD-Detention_v4-06 - Rain Garden.xlsm, Outlet Structure 2/10/2025, 10:59 AM COUNTA for Basin Tab =1 Ao Dia WQ Plate Type Vert Orifice 1Vert Orifice 2 Count_Underdrain =1 0.11 1 1 1 Count_WQPlate =0 0.14 Count_VertOrifice1 =0 0.18 Outlet Plate 1 Outlet Plate 2 Drain Time Message Boolean Count_VertOrifice2 =0 0.24 4 4 5yr, <72hr 0 Count_Weir1 =1 0.29 >5yr, <120hr 0 Count_Weir2 =1 0.36 Max Depth Row Count_OutletPipe1 =1 0.42 WQCV 137 Count_OutletPipe2 =1 0.50 2 Year 165 COUNTA_2 (Standard FSD Setup)=1 0.58 EURV 334 Hidden Parameters & Calculations 0.67 5 Year 186 MaxPondDepth_Error?FALSE 0.76 10 Year 221 Spillway Depth Cd_Broad-Crested Weir 3.00 0.86 25 Year 264 WQ Plate Flow at 100yr depth =0.00 0.97 50 Year 282 CLOG #1=100%1.08 100 Year 324 1 Z1_Boolean n*Cdw #1 =0.62 1.20 500 Year 335 1 Z2_Boolean n*Cdo #1 =0.96 1.32 Zone3_Pulldown Message 1 Z3_Boolean Overflow Weir #1 Angle =0.000 1.45 1 Opening Message CLOG #2=100%1.59 Draintime Running n*Cdw #2 =0.44 1.73 Outlet Boolean Outlet Rank Total (1 to 4) n*Cdo #2 =1.83 1.88 Vertical Orifice 1 0 0 2 Overflow Weir #2 Angle =0.245 2.03 Vertical Orifice 2 0 0 Boolean Underdrain Q at 100yr depth =0.19 2.20 Overflow Weir 1 1 1 0 Max Depth VertOrifice1 Q at 100yr depth =0.00 2.36 Overflow Weir 2 1 2 0 500yr Depth VertOrifice2 Q at 100yr depth =0.00 2.54 Outlet Pipe 1 1 1 0 Freeboard 2.72 Outlet Pipe 2 1 2 0 Spillway Count_User_Hydrographs 0 2.90 0 Spillway Length CountA_3 (EURV & 100yr) =0 3.09 FALSE Time Interval CountA_4 (100yr Only) =1 3.29 Button Visibility Boolean COUNTA_5 (FSD Weir Only)=0 1 WQCV Underdrain COUNTA_6 (EURV Weir Only)=0 0 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 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 30 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 4.06 (July 2022) 0 5 10 15 20 25 30 35 40 0.1 1 10 FL O W [ c f s ] 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 10 100 PO N D I N G D E P T H [ f t ] DRAIN TIME [hr] 500YR 100YR 50YR 25YR 10YR 5YR 2YR EURV WQCV 0 5 10 15 20 25 30 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 OU T F L O W [ c f s ] AR E A [ f t ^ 2 ] , V O L U M E [ f t ^ 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] MHFD-Detention_v4-06 - Rain Garden.xlsm, Outlet Structure 2/10/2025, 10:59 AM 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 [ft][ft 2][acres][ft 3][ac-ft][cfs] 0.00 3,022 0.069 0 0.000 0.00 0.50 3,962 0.091 1,746 0.040 0.13 1.00 5,067 0.116 4,003 0.092 0.14 1.50 5,855 0.134 6,734 0.155 0.65 1.55 5,936 0.136 7,029 0.161 0.94 2.00 6,658 0.153 9,862 0.226 4.75 2.50 7,637 0.175 13,436 0.308 8.24 3.00 8,660 0.199 17,510 0.402 19.06 3.50 9,728 0.223 22,107 0.508 35.95 3.53 9,794 0.225 22,400 0.514 36.77 4.00 10,840 0.249 27,249 0.626 40.18 4.25 11,474 0.263 30,038 0.690 41.88 4.50 12,108 0.278 32,986 0.757 43.52 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 Media Surface - 5106.00 5106.5 5107 5107.5 5107.55 - WQCV MHFD-Detention, Version 4.06 (July 2022) 5108.5 5109 5109.5 5109.53- 100 YR 5110.0 5110.25 5110.5 5108 MHFD-Detention_v4-06 - Rain Garden.xlsm, Outlet Structure 2/10/2025, 10:59 AM Sheet 1 of 2 Designer: Company: Date: Project: Location: 1. Basin Storage Volume A) Effective Imperviousness of Tributary Area, Ia Ia =50.3 % (100% if all paved and roofed areas upstream of rain garden) B) Tributary Area's Imperviousness Ratio (i = Ia/100)i =0.503 C) Water Quality Capture Volume (WQCV) for a 12-hour Drain Time WQCV =0.17 watershed inches 3 2 D) Contributing Watershed Area (including rain garden area)Area = 424,710 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 =0.43 in Average Runoff Producing Storm G) For Watersheds Outside of the Denver Region,VWQCV OTHER =cu ft Water Quality Capture Volume (WQCV) Design Volume H) User Input of Water Quality Capture Volume (WQCV) Design Volume VWQCV USER =5,863 cu ft (Only if a different WQCV Design Volume is desired) 2. Basin Geometry A) WQCV Depth (12-inch maximum)DWQCV =16.2 in 12-INCH MAXIMUM 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 =4273 sq ft D) Actual Flat Surface Area AActual =3022 sq ft ACTUAL FLAT AREA < MINIMUM FLAT AREA E) Area at Design Depth (Top Surface Area)Top =5620 sq ft F) Rain Garden Total Volume VT=5,833 cu ft TOTAL VOLUME < DESIGN VOLUME (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 =2.3 ft Volume to the Center of the Orifice ii) Volume to Drain in 12 Hours Vol12 =5,863 cu ft iii) Orifice Diameter, 3/8" Minimum DO =1 11/16 in Design Procedure Form: Rain Garden (RG) ARJ JR Engineering April 21, 2025 Polestar #1 - Rain Garden; A1-B19 UD-BMP (Version 3.07, March 2018) Choose One Choose One 18" Rain Garden Growing Media Other (Explain): YES NO No. 1 UD BMP _v3.07.xlsm, RG 4/21/2025, 3:56 PM Sheet 2 of 2 Designer: Company: Date: Project: Location: 5. Impermeable Geomembrane Liner and Geotextile Separator Fabric A) Is an impermeable liner provided due to proximity of structures or groundwater contamination? 6. Inlet / Outlet Control A) Inlet Control 7. Vegetation 8. Irrigation A) Will the rain garden be irrigated? Notes: Design Procedure Form: Rain Garden (RG) ARJ JR Engineering April 21, 2025 Polestar #1 - Rain Garden; A1-B19 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 No. 1 UD BMP _v3.07.xlsm, RG 4/21/2025, 3:56 PM Sheet 1 of 2 Designer: Company: Date: Project: Location: 1. Basin Storage Volume A) Effective Imperviousness of Tributary Area, Ia Ia =55.5 % (100% if all paved and roofed areas upstream of rain garden) B) Tributary Area's Imperviousness Ratio (i = Ia/100)i =0.555 C) Water Quality Capture Volume (WQCV) for a 12-hour Drain Time WQCV =0.18 watershed inches 3 2 D) Contributing Watershed Area (including rain garden area)Area =67,518 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 =0.43 in Average Runoff Producing Storm G) For Watersheds Outside of the Denver Region,VWQCV OTHER =cu ft Water Quality Capture Volume (WQCV) Design Volume H) User Input of Water Quality Capture Volume (WQCV) Design Volume VWQCV USER =999 cu ft (Only if a different WQCV Design Volume is desired) 2. Basin Geometry A) WQCV Depth (12-inch maximum)DWQCV =7.6 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 =749 sq ft D) Actual Flat Surface Area AActual =870 sq ft E) Area at Design Depth (Top Surface Area)Top =3143 sq ft F) Rain Garden Total Volume VT=1,271 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 =2.3 ft Volume to the Center of the Orifice ii) Volume to Drain in 12 Hours Vol12 =999 cu ft iii) Orifice Diameter, 3/8" Minimum DO =11/16 in Design Procedure Form: Rain Garden (RG) ARJ JR Engineering April 21, 2025 Polestar #2 - Rain Garden; B1-B2 UD-BMP (Version 3.07, March 2018) Choose One Choose One 18" Rain Garden Growing Media Other (Explain): YES NO No. 2 UD BMP _v3.07.xlsm, RG 4/21/2025, 4:05 PM Sheet 2 of 2 Designer: Company: Date: Project: Location: 5. Impermeable Geomembrane Liner and Geotextile Separator Fabric A) Is an impermeable liner provided due to proximity of structures or groundwater contamination? 6. Inlet / Outlet Control A) Inlet Control 7. Vegetation 8. Irrigation A) Will the rain garden be irrigated? Notes: Design Procedure Form: Rain Garden (RG) ARJ JR Engineering April 21, 2025 Polestar #2 - Rain Garden; B1-B2 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 No. 2 UD BMP _v3.07.xlsm, RG 4/21/2025, 4:05 PM Sheet 1 of 2 Designer: Company: Date: Project: Location: 1. Basin Storage Volume A) Effective Imperviousness of Tributary Area, Ia Ia =55.0 % (100% if all paved and roofed areas upstream of rain garden) B) Tributary Area's Imperviousness Ratio (i = Ia/100)i =0.550 C) Water Quality Capture Volume (WQCV) for a 12-hour Drain Time WQCV =0.18 watershed inches 3 2 D) Contributing Watershed Area (including rain garden area)Area =39,204 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 =0.43 in Average Runoff Producing Storm G) For Watersheds Outside of the Denver Region,VWQCV OTHER =cu ft Water Quality Capture Volume (WQCV) Design Volume H) User Input of Water Quality Capture Volume (WQCV) Design Volume VWQCV USER =576 cu ft (Only if a different WQCV Design Volume is desired) 2. Basin Geometry A) WQCV Depth (12-inch maximum)DWQCV =6.8 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 =431 sq ft D) Actual Flat Surface Area AActual =507 sq ft E) Area at Design Depth (Top Surface Area)Top =1527 sq ft F) Rain Garden Total Volume VT=576 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 =2.3 ft Volume to the Center of the Orifice ii) Volume to Drain in 12 Hours Vol12 =576 cu ft iii) Orifice Diameter, 3/8" Minimum DO =9/16 in Design Procedure Form: Rain Garden (RG) ARJ JR Engineering February 10, 2025 Polestar Village Rain Garden No. 3; Basins C1-C2 and D8 UD-BMP (Version 3.07, March 2018) Choose One NO No. 3 UD BMP _v3.07.xlsm, RG 2/10/2025, 10:38 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) ARJ JR Engineering February 10, 2025 Polestar Village Rain Garden No. 3; Basins C1-C2 and D8 Choose One NO No. 3 UD BMP _v3.07.xlsm, RG 2/10/2025, 10:38 AM Sheet 1 of 2 Designer: Company: Date: Project: Location: 1. Basin Storage Volume A) Effective Imperviousness of Tributary Area, Ia Ia =60.5 % (100% if all paved and roofed areas upstream of rain garden) B) Tributary Area's Imperviousness Ratio (i = Ia/100)i =0.605 C) Water Quality Capture Volume (WQCV) for a 12-hour Drain Time WQCV =0.19 watershed inches 3 2 D) Contributing Watershed Area (including rain garden area)Area =12,197 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 =0.43 in Average Runoff Producing Storm G) For Watersheds Outside of the Denver Region,VWQCV OTHER =cu ft Water Quality Capture Volume (WQCV) Design Volume H) User Input of Water Quality Capture Volume (WQCV) Design Volume VWQCV USER =193 cu ft (Only if a different WQCV Design Volume is desired) 2. Basin Geometry A) WQCV Depth (12-inch maximum)DWQCV =7.5 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 =148 sq ft D) Actual Flat Surface Area AActual =177 sq ft E) Area at Design Depth (Top Surface Area)Top =475 sq ft F) Rain Garden Total Volume VT=204 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 =2.3 ft Volume to the Center of the Orifice ii) Volume to Drain in 12 Hours Vol12 =193 cu ft iii) Orifice Diameter, 3/8" Minimum DO =5/16 in LESS THAN MINIMUM. USE DIAMETER OF 3/8" Design Procedure Form: Rain Garden (RG) ARJ JR Engineering August 22, 2024 Polestar Village Rain Garden No. 4; Basins D6 UD-BMP (Version 3.07, March 2018) Choose One NO No. 4 UD BMP _v3.07.xlsm, RG 8/22/2024, 4:33 PM Sheet 2 of 2 Designer: Company: Date: Project: Location: 5. Impermeable Geomembrane Liner and Geotextile Separator Fabric A) Is an impermeable liner provided due to proximity of structures or groundwater contamination? 6. Inlet / Outlet Control A) Inlet Control 7. Vegetation 8. Irrigation A) Will the rain garden be irrigated? Notes: Design Procedure Form: Rain Garden (RG) ARJ JR Engineering August 22, 2024 Polestar Village Rain Garden No. 4; Basins D6 Choose One NO No. 4 UD BMP _v3.07.xlsm, RG 8/22/2024, 4:33 PM Sheet 1 of 2 Designer: Company: Date: Project: Location: 1. Basin Storage Volume A) Effective Imperviousness of Tributary Area, Ia Ia =64.3 % (100% if all paved and roofed areas upstream of rain garden) B) Tributary Area's Imperviousness Ratio (i = Ia/100)i =0.643 C) Water Quality Capture Volume (WQCV) for a 12-hour Drain Time WQCV =0.20 watershed inches 3 2 D) Contributing Watershed Area (including rain garden area)Area =23,522 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 =0.43 in Average Runoff Producing Storm G) For Watersheds Outside of the Denver Region,VWQCV OTHER =cu ft Water Quality Capture Volume (WQCV) Design Volume H) User Input of Water Quality Capture Volume (WQCV) Design Volume VWQCV USER =394 cu ft (Only if a different WQCV Design Volume is desired) 2. Basin Geometry A) WQCV Depth (12-inch maximum)DWQCV =9.5 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 =302 sq ft D) Actual Flat Surface Area AActual =309 sq ft E) Area at Design Depth (Top Surface Area)Top =742 sq ft F) Rain Garden Total Volume VT=416 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 =2.33 ft Volume to the Center of the Orifice ii) Volume to Drain in 12 Hours Vol12 =394 cu ft iii) Orifice Diameter, 3/8" Minimum DO =7/16 in Design Procedure Form: Rain Garden (RG) ARJ JR Engineering August 22, 2024 Polestar Village Rain Garden No. 5; Basins D4 UD-BMP (Version 3.07, March 2018) Choose One NO No. 5 UD BMP _v3.07.xlsm, RG 8/22/2024, 4:37 PM Sheet 2 of 2 Designer: Company: Date: Project: Location: 5. Impermeable Geomembrane Liner and Geotextile Separator Fabric A) Is an impermeable liner provided due to proximity of structures or groundwater contamination? 6. Inlet / Outlet Control A) Inlet Control 7. Vegetation 8. Irrigation A) Will the rain garden be irrigated? Notes: Design Procedure Form: Rain Garden (RG) ARJ JR Engineering August 22, 2024 Polestar Village Rain Garden No. 5; Basins D4 Choose One NO No. 5 UD BMP _v3.07.xlsm, RG 8/22/2024, 4:37 PM Sheet 1 of 2 Designer: Company: Date: Project: Location: 1. Basin Storage Volume A) Effective Imperviousness of Tributary Area, Ia Ia =65.0 % (100% if all paved and roofed areas upstream of rain garden) B) Tributary Area's Imperviousness Ratio (i = Ia/100)i =0.650 C) Water Quality Capture Volume (WQCV) for a 12-hour Drain Time WQCV =0.20 watershed inches 3 2 D) Contributing Watershed Area (including rain garden area)Area =31,799 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 =0.43 in Average Runoff Producing Storm G) For Watersheds Outside of the Denver Region,VWQCV OTHER =cu ft Water Quality Capture Volume (WQCV) Design Volume H) User Input of Water Quality Capture Volume (WQCV) Design Volume VWQCV USER =539 cu ft (Only if a different WQCV Design Volume is desired) 2. Basin Geometry A) WQCV Depth (12-inch maximum)DWQCV =8 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 =413 sq ft D) Actual Flat Surface Area AActual =430 sq ft E) Area at Design Depth (Top Surface Area)Top =1283 sq ft F) Rain Garden Total Volume VT=571 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 =2.3 ft Volume to the Center of the Orifice ii) Volume to Drain in 12 Hours Vol12 =539 cu ft iii) Orifice Diameter, 3/8" Minimum DO =1/2 in Design Procedure Form: Rain Garden (RG) ARJ JR Engineering August 22, 2024 Polestar Village Rain Garden No. 6; Basins D1- D3 UD-BMP (Version 3.07, March 2018) Choose One NO No. 6 UD BMP _v3.07.xlsm, RG 8/22/2024, 4:41 PM Sheet 2 of 2 Designer: Company: Date: Project: Location: 5. Impermeable Geomembrane Liner and Geotextile Separator Fabric A) Is an impermeable liner provided due to proximity of structures or groundwater contamination? 6. Inlet / Outlet Control A) Inlet Control 7. Vegetation 8. Irrigation A) Will the rain garden be irrigated? Notes: Design Procedure Form: Rain Garden (RG) ARJ JR Engineering August 22, 2024 Polestar Village Rain Garden No. 6; Basins D1- D3 Choose One NO No. 6 UD BMP _v3.07.xlsm, RG 8/22/2024, 4:41 PM 22 APPENDIX E – REFERENCES Appendix J Hydrology Appendix J-1 Vicinity Map A Westrian Company Appendix J-2 Calculations and Exhibits Subdivision:Polestar Project Name:Polestar Location:Fort Collins Project No.: Calculated By:ARJ Checked By:0 Date:2/7/23 Tributary Area Width L=A/W Slope % Imperv N-Imperv N-Perv Store Imperv.Dstore perv.Zero % imperv. Storage (max) Storage (min)Decay Rate Sub-basin 17 25.5 3968.00 279.93 1.00%45.0%0.016 0.1 0.1 0.3 25 0.51 0.5 6.48 15 30.0 4356.00 300.00 2.00%25.0%0.016 0.1 0.1 0.3 25 0.51 0.5 6.48 Note: Only these two basin in the existing Hydrology were modified. Note: City of Fort Collins 2018 Criteria Recommends 1 for Zero % imperv. In the existing SWMM model this was 25. Note: City of Fort Collins 2018 Criteria Recommends 0.25 for N-Perv. In the existing SWMM model this mas 0.1. Tributary Area Width L=A/W Slope % Imperv N-Imperv N-Perv Store Imperv.Dstore perv.Zero % imperv. Storage (max) Storage (min)Decay Rate Sub-basin EP 21.5 1205.33 777.00 1.64%3.7%0.016 0.25 0.1 0.3 1 0.51 0.5 6.48 17W 10.2 1481.04 300.00 0.60%45.0%0.016 0.25 0.1 0.3 1 0.51 0.5 6.48 17E 14.8 2148.96 300.00 1.33%45.0%0.016 0.25 0.1 0.3 1 0.51 0.5 6.48 15E 9.0 1306.80 300.00 1.19%45.0%0.016 0.25 0.1 0.3 1 0.51 0.5 6.48 Tributary Area Width L=A/W Slope % Imperv N-Imperv N-Perv Store Imperv.Dstore perv.Zero % imperv. Storage (max) Storage (min)Decay Rate Sub-basin P 21.5 1572.48 595.58 0.86%50.0%0.016 0.25 0.1 0.3 1 0.51 0.5 6.48 17W 10.2 1481.04 300.00 0.60%45.0%0.016 0.25 0.1 0.3 1 0.51 0.5 6.48 17E 14.8 2148.96 300.00 1.33%45.0%0.016 0.25 0.1 0.3 1 0.51 0.5 6.48 15E 9.0 1306.80 300.00 1.19%45.0%0.016 0.25 0.1 0.3 1 0.51 0.5 6.48 Tributary Area Width L=A/W Slope % Imperv N-Imperv N-Perv Store Imperv.Dstore perv.Zero % imperv. Storage (max) Storage (min)Decay Rate Sub-basin P 21.5 1572.48 595.58 0.86%50.0%0.016 0.25 0.1 0.3 1 0.51 0.5 6.48 17W 10.2 1481.04 300.00 0.60%45.0%0.016 0.25 0.1 0.3 1 0.51 0.5 6.48 17E 14.8 2148.96 300.00 1.33%45.0%0.016 0.25 0.1 0.3 1 0.51 0.5 6.48 15E 9.0 1306.80 300.00 1.19%45.0%0.016 0.25 0.1 0.3 1 0.51 0.5 6.48 SWMM INPUTS 39797.01 Basin inputs City of Fort Collins Default Inputs City of Fort Collins Horton inputs Existing SWMM INPUTS Basin inputs City of Fort Collins Default Inputs City of Fort Collins Horton inputs Proposed SWMM INPUTS 2014 SWMM - 100yr Canal Importation Hydrology Update Basin inputs City of Fort Collins Default Inputs City of Fort Collins Horton inputs Ultimate SWMM INPUTS Basin inputs City of Fort Collins Default Inputs City of Fort Collins Horton inputs X:\3970000.all\3979701\Excel\Drainage\3979701 Drainage_Calcs_Template_v2.07.xlsm Page 1 of 1 2/9/2023 REQUIRED POLESTAR DETENTION POND VOLUME The onsite detention for the site i.e. the required runoff difference between the 100 year developed inflow rate and the 2-year historic runoff is 4.88 Acre-ft. In the SWMM model. P - 100 year developed inflow 1.61*106 Gallons of total runoff EP - 2-year existing inflow 0.02*106 Gallons of total runoff (1.61*106 - 0.02*106) gallons (𝟏𝒇𝒕𝟑 𝟕.𝟒𝟖𝟎𝟓𝒈𝒂𝒍𝒍𝒐𝒏𝒔)* (𝟏𝒂𝒄𝒓𝒆 𝟒𝟑,𝟓𝟔𝟎𝒇𝒕𝟑) = 4.88 Acre-ft. P - Peak Runoff – 119.98 CFS EP - 2 Year Peak Runoff – 2.31 CFS 0 20 40 60 80 100 120 140 0:00:00 1:12:00 2:24:00 3:36:00 4:48:00 6:00:00 7:12:00 8:24:00 Ru n o f f - C F S Time Time vs. Runoff 2 Year Existing (Basin EP) 100 Year Developed (Basin P) Proposed Polestar Pond Drain time PROPOSED –WATER QUALITY FOR POLESTAR DETENTION POND Subdivision:Polestar Project Name:Polestar Location:Fort Collins Project No.:39797.01 Calculated By:ARJ Checked By:0 Date:11/13/24 Basin (ac)% Imp. F1 3.92 31.2% E1 2.24 41.1% E2 0.54 54.2% E3 0.31 59.0% OS1 0.61 15.2% OS2 0.09 50.8% 17W 10.20 45.0% Total 17.92 41.0% WQCV Drain Time (hr):40 Coefficient, a (Figure 3.2):1.0 WQCV (in):0.18 WQCV (ac-ft):0.33 WQ Pond Tributary Areas WATER QUALITY IN DETENTION POND This table shows the WQ on-site treated in the Polestar Detention pond. This calculation includes 20% contingency for sediment accumulation as shown in equaltion 7-2. PLEASE NOTE area on MHFD sheet was multiplied by 1.2 to account for this. X:\3970000.all\3979701\Excel\Drainage\3979701 Drainage_Calcs_Template_v2.07.xlsm Page 8 of 8 2/10/2025 X:\3970000.all\3979701\Excel\Drainage\3979701 Drainage_Calcs_Template_v2.07.xlsm Page 1 of 1 8/7/2023 PROPOSED POLESTAR DETENTION POND A Westrian Company Project: Basin ID: Depth Increment =1.00 ft Watershed Information Top of Micropool --0.00 ------66 0.002 Selected BMP Type =EDB 5103 --0.19 ------382 0.009 43 0.001 Watershed Area =21.50 acres 5104 --1.19 ------20,275 0.465 10,371 0.238 Watershed Length =1,149 ft 5105 --2.19 ------59,591 1.368 50,303 1.155 Watershed Length to Centroid =689 ft 5106 --3.19 ------87,449 2.008 123,823 2.843 Watershed Slope =0.011 ft/ft 5107 --4.19 ------99,692 2.289 217,394 4.991 Watershed Imperviousness =41.00%percent 5108 --5.19 ------106,050 2.435 320,265 7.352 Percentage Hydrologic Soil Group A =0.0%percent 5109 --6.19 ------112,486 2.582 429,533 9.861 Percentage Hydrologic Soil Group B =34.0%percent 5110 --7.19 ------119,103 2.734 545,328 12.519 Percentage Hydrologic Soil Groups C/D =66.0%percent -------- Target WQCV Drain Time =40.0 hours -------- Location for 1-hr Rainfall Depths = User Input -------- -------- -------- Optional User Overrides -------- Water Quality Capture Volume (WQCV) =0.327 acre-feet acre-feet -------- Excess Urban Runoff Volume (EURV) =0.857 acre-feet acre-feet -------- 2-yr Runoff Volume (P1 = 0.82 in.) =0.521 acre-feet 0.82 inches -------- 5-yr Runoff Volume (P1 = 1.09 in.) =0.792 acre-feet inches -------- 10-yr Runoff Volume (P1 = 1.4 in.) =1.246 acre-feet 1.40 inches -------- 25-yr Runoff Volume (P1 = 1.69 in.) =1.863 acre-feet inches -------- 50-yr Runoff Volume (P1 = 1.99 in.) =2.388 acre-feet inches -------- 100-yr Runoff Volume (P1 = 2.86 in.) =4.070 acre-feet 2.86 inches -------- 500-yr Runoff Volume (P1 = 3.14 in.) =4.594 acre-feet inches -------- Approximate 2-yr Detention Volume =0.487 acre-feet -------- Approximate 5-yr Detention Volume =0.770 acre-feet -------- Approximate 10-yr Detention Volume =1.029 acre-feet -------- Approximate 25-yr Detention Volume =1.199 acre-feet -------- Approximate 50-yr Detention Volume =1.309 acre-feet -------- Approximate 100-yr Detention Volume =1.951 acre-feet -------- Set Zone 1 as WQCV -------- Define Zones and Basin Geometry -------- Zone 1 Volume (WQCV) =0.33 acre-feet -------- Zone 2 Volume (User Defined - Zone 1) =0.00 acre-feet -------- Zone 3 Volume (100-year - Zones 1 & 2) =1.62 acre-feet -------- Total Detention Basin Volume =1.95 acre-feet -------- Initial Surcharge Volume (ISV) =user ft 3 -------- Initial Surcharge Depth (ISD) =user ft -------- Total Available Detention Depth (Htotal) =user ft -------- Depth of Trickle Channel (HTC) =user ft -------- Slope of Trickle Channel (STC) =user ft/ft -------- Slopes of Main Basin Sides (Smain) =user H:V -------- 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 Override Area (ft 2) Length (ft) Override Stage (ft) Stage (ft) Stage - Storage Description Area (ft 2) Width (ft) Polestar - Interim Detention Pond (PLEASE NOTE: THE AREA ON THIS MHFD SHEET WAS MULTIPLIED BY 1.2 TO ACCOUNT FOR SEDIMENTATION FOR WQCV) MHFD-Detention, Version 4.06 (July 2022) Example Zone Configuration (Retention Pond) MHFD-Detention_v4-06 -Interim Pond.xlsm, Basin 11/14/2024, 10:01 AM 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 1.36 Zone 1 (WQCV)1.36 Zone 1 (WQCV) 1.36 Zone 2 (User)1.36 Zone 1 (WQCV) 2.71 2.71 Zone 3 (100-year) DETENTION BASIN STAGE-STORAGE TABLE BUILDER MHFD-Detention, Version 4.06 (July 2022) 0.000 3.130 6.260 9.390 12.520 0.000 0.685 1.370 2.055 2.740 0.00 2.00 4.00 6.00 8.00 Vo l u m e ( a c - f t ) Ar e a ( a c r e s ) Stage (ft.) Area (acres)Volume (ac-ft) 0 29800 59600 89400 119200 0 5 10 15 20 0.00 2.00 4.00 6.00 8.00 Ar e a ( s q . f t . ) Le n g t h , W i d t h ( f t . ) Stage (ft) Length (ft)Width (ft)Area (sq.ft.) MHFD-Detention_v4-06 -Interim Pond.xlsm, Basin 11/14/2024, 10:01 AM Project: Basin ID: Estimated Estimated Stage (ft)Volume (ac-ft)Outlet Type Zone 1 (WQCV)1.36 0.327 Orifice Plate Zone 2 (User)1.36 0.000 Orifice Plate Zone 3 (100-year)2.71 1.624 Weir&Pipe (Restrict) Total (all zones)1.951 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 Centroid of Lowest Orifice =0.00 ft (relative to basin bottom at Stage = 0 ft)WQ Orifice Area per Row =1.222E-02 ft2 Depth at top of Zone using Orifice Plate =1.36 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 =1.76 sq. inches (diameter = 1-1/2 inches)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 0.45 0.91 Orifice Area (sq. inches)1.76 1.76 1.76 Row 9 (optional)Row 10 (optional) Row 11 (optional) Row 12 (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 Not Selected Not Selected Not Selected Not Selected Invert of Vertical Orifice =N/A ft (relative to basin bottom at Stage = 0 ft)Vertical Orifice Area =N/A ft2 Depth at top of Zone using Vertical Orifice =N/A ft (relative to basin bottom at Stage = 0 ft) Vertical Orifice Centroid =N/A feet Vertical Orifice Diameter =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 =1.36 N/A ft (relative to basin bottom at Stage = 0 ft)Height of Grate Upper Edge, Ht =4.98 N/A feet Overflow Weir Front Edge Length =5.00 N/A feet Overflow Weir Slope Length =16.40 N/A feet Overflow Weir Grate Slope =4.42 N/A H:V Grate Open Area / 100-yr Orifice Area =12.63 N/A Horiz. Length of Weir Sides =16.00 N/A feet Overflow Grate Open Area w/o Debris =57.09 N/A ft2 Overflow Grate Type =Type C Grate N/A Overflow Grate Open Area w/ Debris =57.09 N/A ft2 Debris Clogging % =0%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 Not Selected Depth to Invert of Outlet Pipe =0.08 N/A ft (distance below basin bottom at Stage = 0 ft)Outlet Orifice Area =4.52 N/A ft2 Outlet Pipe Diameter =42.00 N/A inches Outlet Orifice Centroid =0.96 N/A feet Restrictor Plate Height Above Pipe Invert =20.00 inches Half-Central Angle of Restrictor Plate on Pipe =1.52 N/A radians User Input: Emergency Spillway (Rectangular or Trapezoidal)Calculated Parameters for Spillway Spillway Invert Stage=4.98 ft (relative to basin bottom at Stage = 0 ft)Spillway Design Flow Depth=0.26 feet Spillway Crest Length =36.80 feet Stage at Top of Freeboard =5.74 feet Spillway End Slopes =2.50 H:V Basin Area at Top of Freeboard =2.52 acres Freeboard above Max Water Surface =0.50 feet Basin Volume at Top of Freeboard =8.71 acre-ft 2.71 feet Discharge at Top of Freeboard =124.13 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 1.09 1.40 1.69 1.99 2.86 3.14 CUHP Runoff Volume (acre-ft) =0.327 0.857 0.521 0.792 1.246 1.863 2.388 4.070 4.594 Inflow Hydrograph Volume (acre-ft) =N/A N/A 0.521 0.792 1.246 1.863 2.388 4.070 4.594 CUHP Predevelopment Peak Q (cfs) =N/A N/A 0.2 1.2 5.4 12.8 17.9 34.2 39.2 OPTIONAL N/A N/A Predevelopment Unit Peak Flow, q (cfs/acre) =N/A N/A 0.01 0.05 0.25 0.60 0.83 1.59 1.82 Peak Inflow Q (cfs) =N/A N/A 6.6 10.3 17.1 26.7 34.1 56.9 64.0 Peak Outflow Q (cfs) =0.2 6.1 0.9 2.3 5.2 10.3 14.5 29.5 30.6 Ratio Peak Outflow to Predevelopment Q =N/A N/A N/A 2.0 1.0 0.8 0.8 0.9 0.8 Structure Controlling Flow =Overflow Weir 1 Overflow Weir 1 Overflow Weir 1 Overflow Weir 1 Overflow Weir 1 Overflow Weir 1 Overflow Weir 1 Outlet Plate 1 Outlet Plate 1 Max Velocity through Grate 1 (fps) =N/A 0.11 0.01 0.0 0.1 0.2 0.2 0.5 0.5 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) =38 39 42 41 39 36 34 27 25 Time to Drain 99% of Inflow Volume (hours) =40 44 46 46 45 43 42 39 38 Maximum Ponding Depth (ft) =1.36 1.96 1.52 1.68 1.89 2.13 2.29 2.71 2.86 Area at Maximum Ponding Depth (acres) =0.62 1.16 0.75 0.91 1.09 1.31 1.43 1.70 1.79 Maximum Volume Stored (acre-ft) =0.330 0.864 0.433 0.574 0.774 1.074 1.295 1.953 2.197 DETENTION BASIN OUTLET STRUCTURE DESIGN MHFD-Detention, Version 4.06 (July 2022) Polestar - Interim Detention Pond (PLEASE NOTE: THE AREA ON THIS MHFD SHEET WAS MULTIPLIED BY 1.2 TO ACCOUNT FOR SEDIMENTATION FOR WQCV) 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 MHFD-Detention_v4-06 -Interim Pond.xlsm, Outlet Structure 11/14/2024, 10:55 AM COUNTA for Basin Tab =1 Ao Dia WQ Plate Type Vert Orifice 1Vert Orifice 2 Count_Underdrain =0 0.11 2 1 1 Count_WQPlate =1 0.14 Count_VertOrifice1 =0 0.18 Outlet Plate 1 Outlet Plate 2 Drain Time Message Boolean Count_VertOrifice2 =0 0.24 4 1 5yr, <72hr 0 Count_Weir1 =1 0.29 >5yr, <120hr 0 Count_Weir2 =0 0.36 Max Depth Row Count_OutletPipe1 =1 0.42 WQCV 137 Count_OutletPipe2 =0 0.50 2 Year 153 COUNTA_2 (Standard FSD Setup)=1 0.58 EURV 197 Hidden Parameters & Calculations 0.67 5 Year 169 MaxPondDepth_Error?FALSE 0.76 10 Year 190 Spillway Depth Cd_Broad-Crested Weir 3.00 0.86 25 Year 214 0.26 WQ Plate Flow at 100yr depth =0.26 0.97 50 Year 230 CLOG #1=100%1.08 100 Year 272 1 Z1_Boolean n*Cdw #1 =0.36 1.20 500 Year 287 1 Z2_Boolean n*Cdo #1 =1.37 1.32 Zone3_Pulldown Message 1 Z3_Boolean Overflow Weir #1 Angle =0.222 1.45 1 Opening Message CLOG #2=N/A 1.59 Draintime Running n*Cdw #2 =N/A 1.73 Outlet Boolean Outlet Rank Total (1 to 4) n*Cdo #2 =N/A 1.88 Vertical Orifice 1 0 0 1 Overflow Weir #2 Angle =N/A 2.03 Vertical Orifice 2 0 0 Boolean Underdrain Q at 100yr depth =0.00 2.20 Overflow Weir 1 1 1 0 Max Depth VertOrifice1 Q at 100yr depth =0.00 2.36 Overflow Weir 2 0 0 0 500yr Depth VertOrifice2 Q at 100yr depth =0.00 2.54 Outlet Pipe 1 1 1 0 Freeboard 2.72 Outlet Pipe 2 0 0 1 Spillway Count_User_Hydrographs 0 2.90 0 Spillway Length CountA_3 (EURV & 100yr) =1 3.09 FALSE Time Interval CountA_4 (100yr Only) =1 3.29 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 S-A-V-D Chart Axis Default X-axis Left Y-Axis Right Y-Axis minimum bound 0.00 0 0 maximum bound 6.00 380,000 130 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 4.06 (July 2022) 0 10 20 30 40 50 60 70 0.1 1 FL O W [ c f s ] 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 0.1 1 10 PO N D I N G D E P T H [ f t ] DRAIN TIME [hr] 500YR 100YR 50YR 25YR 10YR 5YR 2YR EURV WQCV 00 50,000 100,000 150,000 200,000 250,000 300,000 350,000 0.00 1.00 2.00 3.00 4.00 5.00 6.00 AR E A [ f t ^ 2 ] , V O L U M E [ f t ^ 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] MHFD-Detention_v4-06 -Interim Pond.xlsm, Outlet Structure 11/14/2024, 10:55 AM 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 0.00 0.20 0.36 0:15:00 0.00 0.00 0.24 0.78 1.31 0.91 1.33 2.05 2.38 0:20:00 0.00 0.00 2.01 3.04 4.16 2.76 3.50 5.38 6.31 0:25:00 0.00 0.00 4.92 7.77 12.47 6.82 8.89 16.78 20.12 0:30:00 0.00 0.00 6.65 10.33 17.09 20.67 27.33 45.21 51.38 0:35:00 0.00 0.00 6.58 10.17 16.60 26.22 33.86 56.88 64.02 0:40:00 0.00 0.00 6.14 9.29 15.11 26.72 34.12 56.70 63.68 0:45:00 0.00 0.00 5.46 8.33 13.57 24.83 31.66 53.75 60.30 0:50:00 0.00 0.00 4.88 7.58 12.07 22.96 29.23 49.58 55.64 0:55:00 0.00 0.00 4.41 6.80 10.76 20.36 26.02 45.10 50.62 1:00:00 0.00 0.00 3.95 6.05 9.55 17.95 23.03 41.07 46.08 1:05:00 0.00 0.00 3.56 5.40 8.46 15.83 20.37 37.33 41.89 1:10:00 0.00 0.00 3.16 4.96 7.77 13.43 17.32 31.66 35.65 1:15:00 0.00 0.00 2.87 4.54 7.30 11.74 15.19 27.31 30.83 1:20:00 0.00 0.00 2.63 4.12 6.66 10.20 13.19 23.14 26.12 1:25:00 0.00 0.00 2.41 3.73 5.85 8.87 11.44 19.47 21.97 1:30:00 0.00 0.00 2.20 3.36 5.09 7.56 9.70 16.30 18.38 1:35:00 0.00 0.00 1.98 3.00 4.37 6.36 8.10 13.40 15.10 1:40:00 0.00 0.00 1.78 2.56 3.71 5.24 6.62 10.74 12.09 1:45:00 0.00 0.00 1.59 2.17 3.14 4.21 5.27 8.37 9.43 1:50:00 0.00 0.00 1.47 1.91 2.79 3.32 4.14 6.52 7.38 1:55:00 0.00 0.00 1.30 1.75 2.56 2.81 3.49 5.40 6.13 2:00:00 0.00 0.00 1.16 1.61 2.33 2.50 3.09 4.67 5.31 2:05:00 0.00 0.00 0.94 1.31 1.89 1.97 2.42 3.59 4.09 2:10:00 0.00 0.00 0.75 1.04 1.50 1.51 1.86 2.69 3.07 2:15:00 0.00 0.00 0.60 0.82 1.18 1.17 1.44 2.00 2.29 2:20:00 0.00 0.00 0.48 0.65 0.92 0.90 1.10 1.47 1.68 2:25:00 0.00 0.00 0.38 0.51 0.71 0.69 0.83 1.09 1.25 2:30:00 0.00 0.00 0.29 0.39 0.54 0.53 0.63 0.83 0.94 2:35:00 0.00 0.00 0.23 0.30 0.41 0.40 0.47 0.62 0.71 2:40:00 0.00 0.00 0.18 0.23 0.31 0.30 0.36 0.48 0.54 2:45:00 0.00 0.00 0.14 0.17 0.24 0.23 0.27 0.37 0.42 2:50:00 0.00 0.00 0.10 0.13 0.18 0.17 0.21 0.28 0.31 2:55:00 0.00 0.00 0.07 0.09 0.12 0.12 0.15 0.19 0.22 3:00:00 0.00 0.00 0.05 0.06 0.08 0.08 0.10 0.13 0.15 3:05:00 0.00 0.00 0.03 0.04 0.05 0.05 0.06 0.08 0.08 3:10:00 0.00 0.00 0.01 0.02 0.02 0.02 0.03 0.04 0.04 3:15:00 0.00 0.00 0.01 0.01 0.01 0.01 0.01 0.01 0.01 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 10 100 OU T F L O W [ c f s ] MHFD-Detention_v4-06 -Interim Pond.xlsm, Outlet Structure 11/14/2024, 10:55 AM 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 [ft][ft 2][acres][ft 3][ac-ft][cfs] 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 MHFD-Detention, Version 4.06 (July 2022) MHFD-Detention_v4-06 -Interim Pond.xlsm, Outlet Structure 11/14/2024, 10:55 AM ULTIMATE POLESTAR DETENTION POND A Westrian Company HAPPY HEART FARMS DETENTION POND BY JACOBS ENGINEERING GROUP Project: Basin ID: Depth Increment =1.00 ft Watershed Information Top of Micropool --0.00 ------32 0.001 Selected BMP Type =EDB 5099 --0.99 ------12,276 0.282 6,092 0.140 Watershed Area =21.50 acres 5100 --1.99 ------42,526 0.976 33,493 0.769 Watershed Length =1,149 ft 5101 --2.99 ------62,048 1.424 85,780 1.969 Watershed Length to Centroid =689 ft 5102 --3.99 ------69,405 1.593 151,506 3.478 Watershed Slope =0.011 ft/ft 5103 --4.99 ------75,067 1.723 223,742 5.136 Watershed Imperviousness =41.00%percent 5104 --5.99 ------80,847 1.856 301,699 6.926 Percentage Hydrologic Soil Group A =0.0%percent 5105 --6.99 ------86,761 1.992 385,503 8.850 Percentage Hydrologic Soil Group B =34.0%percent 5106 --7.99 ------93,012 2.135 475,390 10.913 Percentage Hydrologic Soil Groups C/D =66.0%percent 5107 --8.99 ------99,265 2.279 571,528 13.120 Target WQCV Drain Time =40.0 hours 5108 --9.99 ------105,638 2.425 673,979 15.472 Location for 1-hr Rainfall Depths = User Input 5109 --10.99 ------112,095 2.573 782,845 17.972 5110 --11.99 ------118,779 2.727 898,282 20.622 -------- Optional User Overrides -------- Water Quality Capture Volume (WQCV) =0.327 acre-feet acre-feet -------- Excess Urban Runoff Volume (EURV) =0.857 acre-feet acre-feet -------- 2-yr Runoff Volume (P1 = 0.82 in.) =0.521 acre-feet 0.82 inches -------- 5-yr Runoff Volume (P1 = 1.09 in.) =0.792 acre-feet inches -------- 10-yr Runoff Volume (P1 = 1.4 in.) =1.246 acre-feet 1.40 inches -------- 25-yr Runoff Volume (P1 = 1.69 in.) =1.863 acre-feet inches -------- 50-yr Runoff Volume (P1 = 1.99 in.) =2.388 acre-feet inches -------- 100-yr Runoff Volume (P1 = 2.86 in.) =4.070 acre-feet 2.86 inches -------- 500-yr Runoff Volume (P1 = 3.14 in.) =4.594 acre-feet inches -------- Approximate 2-yr Detention Volume =0.487 acre-feet -------- Approximate 5-yr Detention Volume =0.770 acre-feet -------- Approximate 10-yr Detention Volume =1.029 acre-feet -------- Approximate 25-yr Detention Volume =1.199 acre-feet -------- Approximate 50-yr Detention Volume =1.309 acre-feet -------- Approximate 100-yr Detention Volume =1.951 acre-feet -------- Set Zone 1 as WQCV -------- Define Zones and Basin Geometry -------- Zone 1 Volume (WQCV) =0.33 acre-feet -------- Zone 2 Volume (User Defined - Zone 1) =0.00 acre-feet -------- Zone 3 Volume (100-year - Zones 1 & 2) =1.62 acre-feet -------- Total Detention Basin Volume =1.95 acre-feet -------- Initial Surcharge Volume (ISV) =user ft 3 -------- Initial Surcharge Depth (ISD) =user ft -------- Total Available Detention Depth (Htotal) =user ft -------- Depth of Trickle Channel (HTC) =user ft -------- Slope of Trickle Channel (STC) =user ft/ft -------- Slopes of Main Basin Sides (Smain) =user H:V -------- 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 Override Area (ft 2) Length (ft) Override Stage (ft) Stage (ft) Stage - Storage Description Area (ft 2) Width (ft) Polestar - Ultimate Detention Pond (PLEASE NOTE: THE AREA ON THS MHFD SHEET WAS MULTIPLIED BY 1.2 TO ACCOUNT FOR SEDIMENTATION FOR WQCV) MHFD-Detention, Version 4.06 (July 2022) Example Zone Configuration (Retention Pond) MHFD-Detention_v4-06 - Ultimate Pond.xlsm, Basin 11/14/2024, 10:00 AM 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 1.43 Zone 1 (WQCV)1.43 Zone 1 (WQCV) 1.43 Zone 2 (User)1.43 Zone 1 (WQCV) 2.98 2.98 Zone 3 (100-year) DETENTION BASIN STAGE-STORAGE TABLE BUILDER MHFD-Detention, Version 4.06 (July 2022) 0.000 5.160 10.320 15.480 20.640 0.000 0.685 1.370 2.055 2.740 0.00 3.00 6.00 9.00 12.00 Vo l u m e ( a c - f t ) Ar e a ( a c r e s ) Stage (ft.) Area (acres)Volume (ac-ft) 0 29700 59400 89100 118800 0 5 10 15 20 0.00 3.00 6.00 9.00 12.00 Ar e a ( s q . f t . ) Le n g t h , W i d t h ( f t . ) Stage (ft) Length (ft)Width (ft)Area (sq.ft.) MHFD-Detention_v4-06 - Ultimate Pond.xlsm, Basin 11/14/2024, 10:00 AM Project: Basin ID: Estimated Estimated Stage (ft) Volume (ac-ft)Outlet Type Zone 1 (WQCV)1.43 0.327 Orifice Plate Zone 2 (User)1.43 0.000 Orifice Plate Zone 3 (100-year)2.98 1.624 Weir&Pipe (Restrict) Total (all zones)1.951 User Input: Orifice at Underdrain Outlet (typically used to drain WQCV in a Filtration BMP)Calculated Parameters for Underdrain Underdrain Orifice Invert Depth =ft (distance below the filtration media surface)Underdrain Orifice Area =ft2 Underdrain Orifice Diameter =inches Underdrain Orifice Centroid =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 Centroid of Lowest Orifice =0.00 ft (relative to basin bottom at Stage = 0 ft)WQ Orifice Area per Row =1.313E-02 ft2 Depth at top of Zone using Orifice Plate =1.43 ft (relative to basin bottom at Stage = 0 ft)Elliptical Half-Width =N/A feet Orifice Plate: Orifice Vertical Spacing =5.70 inches Elliptical Slot Centroid =N/A feet Orifice Plate: Orifice Area per Row =1.89 sq. inches (diameter = 1-9/16 inches)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 5 (optional) Row 6 (optional)Row 7 (optional)Row 8 (optional) Stage of Orifice Centroid (ft)0.00 0.48 0.95 Orifice Area (sq. inches)1.89 1.89 1.89 Row 9 (optional)Row 10 (optional)Row 11 (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 Not Selected Not Selected Not Selected Not Selected Invert of Vertical Orifice =N/A N/A ft (relative to basin bottom at Stage = 0 ft) Vertical Orifice Area =N/A N/A ft2 Depth at top of Zone using Vertical Orifice =N/A N/A ft (relative to basin bottom at Stage = 0 ft)Vertical Orifice Centroid =N/A N/A feet Vertical Orifice Diameter =N/A 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 =1.43 N/A ft (relative to basin bottom at Stage = 0 ft)Height of Grate Upper Edge, Ht =4.43 N/A feet Overflow Weir Front Edge Length =5.00 N/A feet Overflow Weir Slope Length =12.37 N/A feet Overflow Weir Grate Slope =4.00 N/A H:V Grate Open Area / 100-yr Orifice Area =15.56 N/A Horiz. Length of Weir Sides =12.00 N/A feet Overflow Grate Open Area w/o Debris =43.05 N/A ft2 Overflow Grate Type =Type C Grate N/A Overflow Grate Open Area w/ Debris =43.05 N/A ft2 Debris Clogging % =0%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 Not Selected Depth to Invert of Outlet Pipe =0.00 N/A ft (distance below basin bottom at Stage = 0 ft)Outlet Orifice Area =2.77 N/A ft2 Outlet Pipe Diameter =30.00 N/A inches Outlet Orifice Centroid =0.79 N/A feet Restrictor Plate Height Above Pipe Invert =16.50 inches Half-Central Angle of Restrictor Plate on Pipe =1.67 N/A radians User Input: Emergency Spillway (Rectangular or Trapezoidal)Calculated Parameters for Spillway Spillway Invert Stage=8.78 ft (relative to basin bottom at Stage = 0 ft)Spillway Design Flow Depth=0.62 feet Spillway Crest Length =36.80 feet Stage at Top of Freeboard =10.50 feet Spillway End Slopes =2.50 H:V Basin Area at Top of Freeboard =2.50 acres Freeboard above Max Water Surface =1.10 feet Basin Volume at Top of Freeboard =16.70 acre-ft Max Ponding Depth of Target Storage Volume =3.17 feet Discharge at Top of Freeboard =311.30 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 1.09 1.40 1.69 1.99 2.86 3.14 CUHP Runoff Volume (acre-ft) =0.327 0.857 0.521 0.792 1.246 1.863 2.388 4.070 4.594 Inflow Hydrograph Volume (acre-ft) =N/A N/A 0.521 0.792 1.246 1.863 2.388 4.070 4.594 CUHP Predevelopment Peak Q (cfs) =N/A N/A 0.2 1.2 5.4 12.8 17.9 34.2 39.2 OPTIONAL Override Predevelopment Peak Q (cfs) =N/A N/A Predevelopment Unit Peak Flow, q (cfs/acre) =N/A N/A 0.01 0.05 0.25 0.60 0.83 1.59 1.82 Peak Inflow Q (cfs) =N/A N/A 6.6 10.3 17.1 26.7 34.1 56.9 64.0 Peak Outflow Q (cfs) =0.2 6.2 0.9 2.3 5.3 10.6 15.1 20.6 21.6 Ratio Peak Outflow to Predevelopment Q =N/A N/A N/A 2.0 1.0 0.8 0.8 0.6 0.6 Structure Controlling Flow =Overflow Weir 1 Overflow Weir 1 Overflow Weir 1 Overflow Weir 1 Overflow Weir 1 Outlet Plate 1 Outlet Plate 1 Max Velocity through Grate 1 (fps) =N/A 0.15 0.02 0.1 0.1 0.2 0.3 0.5 0.5 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) =37 38 41 40 37 34 31 25 24 Time to Drain 99% of Inflow Volume (hours) =40 44 45 45 44 42 41 37 36 Maximum Ponding Depth (ft) =1.43 2.08 1.60 1.78 2.00 2.28 2.46 3.17 3.42 Area at Maximum Ponding Depth (acres) =0.59 1.02 0.70 0.82 0.98 1.10 1.18 1.45 1.50 Maximum Volume Stored (acre-ft) =0.331 0.859 0.434 0.571 0.779 1.060 1.265 2.228 2.582 DETENTION BASIN OUTLET STRUCTURE DESIGN MHFD-Detention, Version 4.06 (July 2022) Polestar - Ultimate Detention Pond (PLEASE NOTE: THE AREA ON THS MHFD SHEET WAS MULTIPLIED BY 1.2 TO ACCOUNT FOR SEDIMENTATION FOR WQCV) 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) MHFD-Detention_v4-06 - Ultimate Pond.xlsm, Outlet Structure 11/14/2024, 9:59 AM COUNTA for Basin Tab =1 Ao Dia WQ Plate Type Vert Orifice 2 Count_Underdrain =0 0.11 2 1 1 Count_WQPlate =1 0.14 Count_VertOrifice1 =0 0.18 Outlet Plate 1 Outlet Plate 2 Drain Time Message Boolean Count_VertOrifice2 =0 0.24 4 1 5yr, <72hr 0 Count_Weir1 =1 0.29 >5yr, <120hr 0 Count_Weir2 =0 0.36 Max Depth Row Count_OutletPipe1 =1 0.42 WQCV 144 Count_OutletPipe2 =0 0.50 2 Year 161 COUNTA_2 (Standard FSD Setup)=1 0.58 EURV 209 Hidden Parameters & Calculations 0.67 5 Year 179 MaxPondDepth_Error?FALSE 0.76 10 Year 201 Spillway Depth Cd_Broad-Crested Weir 3.00 0.86 25 Year 229 0.62 WQ Plate Flow at 100yr depth =0.31 0.97 50 Year 247 CLOG #1=100%1.08 100 Year 318 1 Z1_Boolean n*Cdw #1 =0.32 1.20 500 Year 343 1 Z2_Boolean n*Cdo #1 =1.45 1.32 Zone3_Pulldown Message 1 Z3_Boolean Overflow Weir #1 Angle =0.245 1.45 1 Opening Message CLOG #2=N/A 1.59 Draintime Running n*Cdw #2 =N/A 1.73 Outlet Boolean Outlet Rank Total (1 to 4) n*Cdo #2 =N/A 1.88 Vertical Orifice 1 0 0 1 Overflow Weir #2 Angle =N/A 2.03 Vertical Orifice 2 0 0 Boolean Underdrain Q at 100yr depth =0.00 2.20 Overflow Weir 1 1 1 0 Max Depth VertOrifice1 Q at 100yr depth =0.00 2.36 Overflow Weir 2 0 0 0 500yr Depth VertOrifice2 Q at 100yr depth =0.00 2.54 Outlet Pipe 1 1 1 0 Freeboard 2.72 Outlet Pipe 2 0 0 1 Spillway Count_User_Hydrographs 0 2.90 0 Spillway Length CountA_3 (EURV & 100yr) =1 3.09 FALSE Time Interval CountA_4 (100yr Only) =1 3.29 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 S-A-V-D Chart Axis Default X-axis Left Y-Axis Right Y-Axis minimum bound 0.00 0 0 maximum bound 12.00 730,000 320 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 4.06 (July 2022) 0 10 20 30 40 50 60 70 0.1 1 FL O W [ c f s ] 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 PO N D I N G D E P T H [ f t ] DRAIN TIME [hr] 500YR 100YR 50YR 25YR 10YR 5YR 2YR EURV WQCV 0 50 100 150 200 250 300 0 100,000 200,000 300,000 400,000 500,000 600,000 700,000 0.00 2.00 4.00 6.00 8.00 10.00 AR E A [ f t ^ 2 ] , V O L U M E [ f t ^ 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] MHFD-Detention_v4-06 - Ultimate Pond.xlsm, Outlet Structure 11/14/2024, 9:59 AM 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 0.00 0.20 0.36 0:15:00 0.00 0.00 0.24 0.78 1.31 0.91 1.33 2.05 2.38 0:20:00 0.00 0.00 2.01 3.04 4.16 2.76 3.50 5.38 6.31 0:25:00 0.00 0.00 4.92 7.77 12.47 6.82 8.89 16.78 20.12 0:30:00 0.00 0.00 6.65 10.33 17.09 20.67 27.33 45.21 51.38 0:35:00 0.00 0.00 6.58 10.17 16.60 26.22 33.86 56.88 64.02 0:40:00 0.00 0.00 6.14 9.29 15.11 26.72 34.12 56.70 63.68 0:45:00 0.00 0.00 5.46 8.33 13.57 24.83 31.66 53.75 60.30 0:50:00 0.00 0.00 4.88 7.58 12.07 22.96 29.23 49.58 55.64 0:55:00 0.00 0.00 4.41 6.80 10.76 20.36 26.02 45.10 50.62 1:00:00 0.00 0.00 3.95 6.05 9.55 17.95 23.03 41.07 46.08 1:05:00 0.00 0.00 3.56 5.40 8.46 15.83 20.37 37.33 41.89 1:10:00 0.00 0.00 3.16 4.96 7.77 13.43 17.32 31.66 35.65 1:15:00 0.00 0.00 2.87 4.54 7.30 11.74 15.19 27.31 30.83 1:20:00 0.00 0.00 2.63 4.12 6.66 10.20 13.19 23.14 26.12 1:25:00 0.00 0.00 2.41 3.73 5.85 8.87 11.44 19.47 21.97 1:30:00 0.00 0.00 2.20 3.36 5.09 7.56 9.70 16.30 18.38 1:35:00 0.00 0.00 1.98 3.00 4.37 6.36 8.10 13.40 15.10 1:40:00 0.00 0.00 1.78 2.56 3.71 5.24 6.62 10.74 12.09 1:45:00 0.00 0.00 1.59 2.17 3.14 4.21 5.27 8.37 9.43 1:50:00 0.00 0.00 1.47 1.91 2.79 3.32 4.14 6.52 7.38 1:55:00 0.00 0.00 1.30 1.75 2.56 2.81 3.49 5.40 6.13 2:00:00 0.00 0.00 1.16 1.61 2.33 2.50 3.09 4.67 5.31 2:05:00 0.00 0.00 0.94 1.31 1.89 1.97 2.42 3.59 4.09 2:10:00 0.00 0.00 0.75 1.04 1.50 1.51 1.86 2.69 3.07 2:15:00 0.00 0.00 0.60 0.82 1.18 1.17 1.44 2.00 2.29 2:20:00 0.00 0.00 0.48 0.65 0.92 0.90 1.10 1.47 1.68 2:25:00 0.00 0.00 0.38 0.51 0.71 0.69 0.83 1.09 1.25 2:30:00 0.00 0.00 0.29 0.39 0.54 0.53 0.63 0.83 0.94 2:35:00 0.00 0.00 0.23 0.30 0.41 0.40 0.47 0.62 0.71 2:40:00 0.00 0.00 0.18 0.23 0.31 0.30 0.36 0.48 0.54 2:45:00 0.00 0.00 0.14 0.17 0.24 0.23 0.27 0.37 0.42 2:50:00 0.00 0.00 0.10 0.13 0.18 0.17 0.21 0.28 0.31 2:55:00 0.00 0.00 0.07 0.09 0.12 0.12 0.15 0.19 0.22 3:00:00 0.00 0.00 0.05 0.06 0.08 0.08 0.10 0.13 0.15 3:05:00 0.00 0.00 0.03 0.04 0.05 0.05 0.06 0.08 0.08 3:10:00 0.00 0.00 0.01 0.02 0.02 0.02 0.03 0.04 0.04 3:15:00 0.00 0.00 0.01 0.01 0.01 0.01 0.01 0.01 0.01 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 10 100 0 50 100 150 200 250 300 OU T F L O W [ c f s ] MHFD-Detention_v4-06 - Ultimate Pond.xlsm, Outlet Structure 11/14/2024, 9:59 AM 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 [ft][ft 2][acres][ft 3][ac-ft][cfs] 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 MHFD-Detention, Version 4.06 (July 2022) MHFD-Detention_v4-06 - Ultimate Pond.xlsm, Outlet Structure 11/14/2024, 9:59 AM Project Name:Polestar Subdivision:Polestar Project No.: Location:Fort Collins Calculated By:ARJ Checked By:0 Date:11/13/24 Head (ft)Discharge (cfs)Head (ft)Discharge (cfs) 0 0.00 0 0.00 0.5 0.05 0.5 0.05 1 0.12 1 0.12 1.36 0.16 1.43 0.18 1.5 0.73 1.5 0.35 2 7.29 2 5.26 2.5 21.17 2.5 16.23 3 31.67 3 19.82 3.5 35.21 3.5 21.94 4 38.42 4 23.88 4.5 41.39 4.5 25.67 5 44.15 5 27.34 5.5 46.76 5.5 28.92 6 49.22 6 30.41 6.5 51.57 6.5 31.84 7 53.82 7 33.20 SEE WQCV STAGE IN RED 8 35.77 8.5 36.99 9 38.17 9.5 39.32 SEE WQCV STAGE IN RED WQ orifice plate, w/ Restrictor Plate 42" Pipe and Overflow Structure INTERIM_OUTLET ULTIMATE_OUTLET WQ orifice plate, 30" Pipe w/ Restrictor plate and Overflow Structure Stage Discharge 39797.01 NOTE: In the Jacobs SWMM model the outfall was modeled as a 30" unrestricted pipe. Appendix J-3 SWMM Maps % % % % % % % § § § § % % % % % % % % % % % % % %% %% %%% % %%%% % § % §§ §§ %%§§ % § % % %% %%%% % % % % %%% %% % % % %% % % % % % %%% %% § %%%%§§ % % % %% % % %%%% % § %%% % § §%§ § % %%%%%%%%% § % % %% % % % % § % %% %§ % % % %% %% % % %% % % § %% % % % % % % % %% % § %%%%% § §%% % % % % % !( !( !( !(!( !( !( !( !( !( !( !( !( !( !(!(!( !( !( !( !( !( !( !( !( !( !( !( !( !( !( !( !( !( !(!(!( !( !( !( !( !(!( !( !(!(!( !( !( !(!( !( !( !( !( !(!( !( !(!(!( !( !( !(!( !( !( !( !( !( !( !( !(!(!(!( !( !( !( !(!( !( !( !( !( !( !( !( !( !( !( !( !( !( !( !( !( !( !(!( !( !( !( !( !( !( !( !( !(!( !( !( !( !( !( !( !( !( !( !( !( !( !( !( !( !( !(!( !( !( !( !(!( !( !( !( !( !( !( !( !( !( !(!(!(!( !( !( #* #* #* #* #* #* #* #* #* #* #* #* #* #*#* #* #* #* #* #* #* #* #* #* #* #* #* ©L ©L ©L ©L ©L ©L ©L ©L ©L ©L ©L ©L ©L ©L ©L ©L ©L ©L ©L ©L ©L ©L ©L Ä2þ 24 5 ac. Ä2þ 98 2 ac. Äþ Ä2þ 1 7.7 ac. Ä2þ 6 6.9 ac. Ä2þ 10 65 ac.Ä2þ 553 8 ac. Ä2þ 15 30 ac. Ä2þ 99 12 ac.Ä2þ 95 33 ac. Ä2þ 583 2 ac. Ä2þ 549 4 ac. Ä2þ 68 42 ac. Ä2þ 72 30 ac. Ä2þ 577 7 ac. Ä2þ 4 22.2 ac. Ä2þ 7 18.4 ac. Ä2þ 3 39.1 ac.Ä2þ 5 21.3 ac.Ä2þ 2 30.4 ac. Ä2þ 8 12.9 ac. Ä2þ 22 9.7 ac. Ä2þ 13 2.9 ac. Ä2þ 19 9.6 ac. Ä2þ 14 3.3 ac.Ä2þ 9 12.8 ac. Ä2þ 67 7.9 ac. Ä2þ 94 7.9 ac. Ä2þ 93 7.6 ac. Ä2þ 87 5.6 ac. Ä2þ 98 0.8 ac. Ä2þ 44 14.5 ac. Ä2þ 108 8.8 ac.Ä2þ 12 17.8 ac. Ä2þ 21 22.2 ac. Ä2þ 17 25.5 ac. Ä2þ 593 2.8 ac. Ä2þ 20 28.6 ac. Ä2þ 513 2.8 ac.Ä2þ 720 4.6 ac.Ä2þ 423 0.9 ac. Ä2þ 503 0.6 ac. Ä2þ 222 4.7 ac. Ä2þ 16 13.7 ac.Ä2þ 18 51.1 ac.Ä2þ 433 1.2 ac. Ä2þ 563 1.5 ac. Ä2þ 11 23.1 ac. Ä2þ 820 7.5 ac.Ä2þ 116 7.7 ac.Ä2þ 533 5.8 ac.Ä2þ 573 0.9 ac. Ä2þ 543 3.2 ac. Ä2þ 224 6.4 ac. Ä2þ 523 3.1 ac. Ä2þ 495 5.4 ac. Ä2þ 118 3.3 ac. Ä2þ 519 1.6 ac. Ä2þ 529 0.7 ac.Ä2þ 66 11.8 ac.Ä2þ 569 3.4 ac. Ä2þ 69 26.2 ac.Ä2þ 75 32.8 ac.Ä2þ 579 2.8 ac. Ä2þ 559 0.9 ac.Ä2þ 509 0.9 ac.Ä2þ 539 1.2 ac.Ä2þ 97 13.4 ac. Ä2þ 598 1.7 ac. Ä2þ 588 8.9 ac. Ä2þ 71 30.4 ac. Ä2þ 520 1.7 ac. Ä2þ 550 5.7 ac.Ä2þ 570 2.3 ac.Ä2þ 70 26.5 ac.Ä2þ 73 13.5 ac. Ä2þ 530 2.5 ac. Ä2þ 96 10.3 ac. Ä2þ 560 4.3 ac. Ä2þ 74 13.9 ac.Ä2þ 587 3.9 ac.Ä2þ 580 7.2 ac. þ Ä2þ 139 51.2 ac.Ä2þ 140 56.8 ac. Ä2þ 111 24.6 ac.Ä2þ 110 18.5 ac. Ä2þ 109 14.7 ac. Ä2þ 113 13.5 ac. Ä2þ 112 11.1 ac. Ä2þ 114 14.1 ac.Ä2þ 115 20.1 ac. Ä2þ 117 11.2 ac. Ä2þ 589 15.6 ac.Ä2þ 195 28.9 ac.Ä2þ 119 24.6 ac. Ä2þ 978 10.8 ac.Ä2þ 219 23.8 ac. Ä2þ 120 34.4 ac. Ä2þ 578 10.3 ac. Ä2þ 597 11.1 ac. J9 J8 J5 J4 J3J2 J1 I8 I7 I5 I4 299 399 396 395 390 378370368 367366 344 324 322 319 318 317 316 315 313 310 308 304 301 802 414 410 J94 J93 J75 J74 J34 J22 J21 J17 J10 I17 I13 I12 I10 A31 A30 A28 A27 A26 A25 A24 A23 A22 A21 A19 A17 A15 A14 995 879 874 873 872 871 869 863 862 861 859 856 855 854 853 852 850 311 306 303 302 300 290 276 274 272 220 205 PP_4 PP_3PP_2 PP_1 J945 J944 J878 J720 J719 J715 J714 J713J712 J711 J709 J598 J593 J589 J587 J583 J580 J579 J577 J573 J570 J569 J563 J559 J550 J549 J543 J539 J533 J529 J520 J519 J513 J433 J424 J423 J418 J190 J167 J148 J123 J121 J120 J118 J117 J116J115 J113J110 J108 J105J103J102J101 IB-3 IB-1 I6-4 I6-3 I6-2 I6-1 GC_2 A16a 529out 519out J543_US 8 Outfall 446 Spill 445 Spill 444 Spill 442 Spill 441 Spill 428 Spill 47 Outfall 119 Storage 720 Outfall 719 Outfall 715 Outfall 714 Outfall 713 Outfall 712 Outfall 549_outfall 520 Outfall 424 Outfall 318 Outfall 317 Outfall 311_outfall 299 Outfall GC 3 Inlet Skyline Inlet2 Skyline I17-1 870 378 Outfall Skyline EX-2 278 Outfall I7-1 Avery LowFlow 1, 2, 3 Avery Outlet J523 I12-1 GC_5 Ov e r l a n d T r a i l Ov e r l a n d T r a i l Ta f t H i l l R o a d Laporte Avenue Elizabeth Street Mulberry Street Mulberry Street 9 95 10 17 68 5 94 75 73 118 428 88 187 1 176 711 433 103 709 8 74 149 15 878 21 287 76 171 93 C11 715 A18 87 148 589 113 C21 560 189 550 101 593 86 20 712 713 563 172 105_pipe 24 C20 12 1 583 108 569 116 944 523b 945 18_pipe 105_overflow PP_3 47 2_pipe 573 104_pipe 533a 543 3_pipe 110_pipe 103_overflow C3 418 587a 577a 167_pipe L8 587b 577b C23 PP_4 188_pipe 285 580 18_overflow 102_pipe A28-850 190 22 283 A14 110_overflow IBa 16_pipe C4 C22 L10 92 L6-2 A22 540 C8 520 719_pipe A20 115_pipe GC_2 288 L17 SHEET: 1 DATE: PROJECT NUMBER: CHECKED BY: DESIGNED BY: DRAWN BY:BNA MMC AMH COFC2012.01 07/01/2014 ³ Legend !(Junction #*Outfall ©L Storage %Conveyance Element Non-Routing Element §Outlet Subbasin 0 400 800200 Feet CI T Y O F F O R T C O L L I N S CA N A L I M P O R T A T I O N H Y D R O L O G I C C O N V E R S I O N FR O M M O D S W M M T O E P A S W M M 5 . 0 SU B B A S I N A N D R O U T I N G E L E M E N T LO C A T I O N M A P A W e s t r i a n C o m p a n y A W e s t r i a n C o m p a n y A W e s t r i a n C o m p a n y A W e s t r i a n C o m p a n y Appendix J-4 Offsite Photos and Calculations POND 315 OUTFALL – DUEL 24” RCP EAST OF KIMBALL STEET ROCKY ROAD – DUEL 24“ STORM UTILITY MARKINGS - (ON WEST SIDE) POND 316 INFLOW PEAR STREET– (FACING WEST) Project: ID: 47187.82 X Design Information (Input): Circular Culvert:Barrel Diameter in Inches D =24 inches Inlet Edge Type (Choose from pull-down list)Grooved Edge Projecting OR: Box Culvert:Barrel Height (Rise) in Feet H (Rise) =ft Barrel Width (Span) in Feet W (Span) =ft Inlet Edge Type (Choose from pull-down list) 2.00 Number of Barrels # Barrels =2 Inlet Elevation at Culvert Invert 5094.40 Elev IN =5096.6 ft Outlet Elevation OR Slope 0.005 So =0.005 ft/ft Culvert Length L =440 ft Manning's Roughness n =0.013 Bend Loss Coefficient Kb =0 Exit Loss Coefficient Kx =1 1 Design Information (calculated): Entrance Loss Coefficient Ke =0.20 Friction Loss Coefficient Kf =5.43 Sum of All Loss Coefficients Ks =6.63 Minimum Energy Condition Coefficient KElow =-0.0028 Orifice Inlet Condition Coefficient Cd =0.67 Calculations of Culvert Capacity (output):Backwater calculations required to obtain Outlet Control Flowrate when HWo < 0.75 * Culvert Rise Headwater Tailwater Inlet Inlet Outlet Controlling Flow Surface Surface Control Control Control Culvert Control Elevation Elevation Equation Flowrate Flowrate Flowrate Used (ft)(ft)Used (cfs)(cfs)(cfs) 5096.60 5095.20 No Flow (WS < inlet)0.00 0.00 0.00 N/A 5096.85 5095.20 Min. Energy. Eqn.0.50 #N/A #N/A #N/A 5097.10 5095.20 Min. Energy. Eqn.2.32 #N/A #N/A #N/A 5097.35 5095.20 Min. Energy. Eqn.5.06 #N/A #N/A #N/A 5097.60 5095.20 Min. Energy. Eqn.8.68 #N/A #N/A #N/A 5097.85 5095.20 Regression Eqn.12.62 #N/A #N/A #N/A 5098.10 5095.20 Regression Eqn.17.28 27.88 17.28 INLET 5098.35 5095.20 Regression Eqn.22.62 29.43 22.62 INLET 5098.60 5095.20 Regression Eqn.27.94 30.91 27.94 INLET 5098.85 5095.20 Regression Eqn.32.94 32.33 32.33 OUTLET 5099.10 5095.20 Regression Eqn.37.42 33.69 33.69 OUTLET 5099.35 5095.20 Regression Eqn.41.46 35.00 35.00 OUTLET 5099.60 5095.20 Regression Eqn.45.10 36.28 36.28 OUTLET 5099.85 5095.20 Regression Eqn.48.44 37.51 37.51 OUTLET 5100.10 5095.20 Regression Eqn.51.54 38.71 38.71 OUTLET 5100.35 5095.20 Regression Eqn.54.44 39.88 39.88 OUTLET 5100.60 5095.20 Regression Eqn.57.22 41.02 41.02 OUTLET 5100.85 5095.20 Regression Eqn.59.82 42.12 42.12 OUTLET 5101.10 5095.20 Regression Eqn.62.30 43.21 43.21 OUTLET 5101.35 5095.20 Regression Eqn.64.70 44.26 44.26 OUTLET 5101.60 5095.20 Regression Eqn.67.04 45.30 45.30 OUTLET 5101.85 5095.20 Regression Eqn.69.30 46.31 46.31 OUTLET 5102.10 5095.20 Regression Eqn.71.48 47.30 47.30 OUTLET 5102.35 5095.20 Regression Eqn.73.62 48.28 48.28 OUTLET Processing Time:00.16 Seconds CULVERT SIZING (INLET vs. OUTLET CONTROL WITH TAILWATER EFFECTS) Kimball Detention (Pond 315 Culverts) MHFD-Culvert, Version 4.00 (May 2020) MHFD-Culvert_v4.0.xlsm, Culvert Rating 3/17/2023, 3:07 PM Project: ID: CULVERT SIZING (INLET vs. OUTLET CONTROL WITH TAILWATER EFFECTS) Kimball Detention (Pond 315 Culverts) MHFD-Culvert, Version 4.00 (May 2020) 5096.6 5097.6 5098.6 5099.6 5100.6 5101.6 5102.6 5103.6 0 20 40 60 80 St a g e ( f e e t , e l e v ) Discharge (cfs) STAGE-DISCHARGE CURVE FOR THE CULVERT Inlet Control Outlet Control Stage-Discharge MHFD-Culvert_v4.0.xlsm, Culvert Rating 3/17/2023, 3:07 PM Stage Discharge Project Name:Polestar Subdivision:Polestar Project No.:39797.01 Location:Fort Collins Calculated By:ARJ Checked By: Date:3/15/2023 Pond 315 - 24" Double Barrel Culvert Outlet Pond 315 - Weir Discharge Elevation Stage (ft)Discharge (cfs)Energy Equation Elevation Stage (ft)Weir Length (ft)Discharge (cfs)5096.60 0.00 0.00 No Flow (WS < inlet) 5100.40 0 0 0.00 5096.85 0.25 0.50 Min. Energy. Eqn. 5100.60 0.2 11.6 2.80 5097.10 0.50 2.32 Min. Energy. Eqn. 5100.80 0.4 15.3 10.45 5097.35 0.75 5.06 Min. Energy. Eqn. 5101.00 0.6 19.6 24.59 5097.60 1.00 8.68 Min. Energy. Eqn. 5101.20 0.8 24.3 46.95 5097.85 1.25 12.62 Regression Eqn. 5101.40 1 43.2 116.64 5098.10 1.50 17.28 INLET 5101.50 1.1 59.9 186.59 5098.35 1.75 22.62 INLET 5101.60 1.2 63.5 225.38 5098.60 2.00 27.94 INLET 5101.70 1.3 75.3 301.35 5098.85 2.25 32.33 OUTLET 5101.80 1.4 87 389.11 5099.10 2.50 33.69 OUTLET offset 3.8 feet from culvert invert at 5096.6 5099.35 2.75 35.00 OUTLET 5099.60 3.00 36.28 OUTLET 5099.85 3.25 37.51 OUTLET 5100.10 3.50 38.71 OUTLET 5100.35 3.75 39.88 OUTLET 5100.60 4.00 41.02 OUTLET 5100.85 4.25 42.12 OUTLET 5101.10 4.50 43.21 OUTLET 5101.35 4.75 44.26 OUTLET 5101.60 5.00 45.30 OUTLET 5101.85 5.25 46.31 OUTLET 5102.10 5.50 47.30 OUTLET 5102.35 5.75 48.28 OUTLET Q=C*L*H^1.5 C=2.7 L=Weir Length H=Height Pond 315 Outlet Pond - Double Barrel Culvert Outlet See Attached MHFD-Culvert_4.0 Spreadsheet Appendix J-5 Flow Comparison COFC2012.01_CI Basin Hydrologic Conversion_Report.docx 13 Anderson Consulting Engineers, Inc. FI G U R E 3 . 1 Table B.1.1 Plum Channel Flow Path Discharge Profil 100‐year/Result to  be Mapped 10‐year 2‐year 5271 113 241 67 10 Upstream Study Limit 4872 15 330 76 18 4277.999 115_pipe/115_overflow*214/140 73 14 Upstream of Rocky Street Culvert 4277 115_pipe/115_overflow*214/140 73 14 Rocky Street Culvert Overtopping 3993 16_pipe/16_overflow*234/160 79 24 3816 16_pipe/16_overflow*234/160 79 24 3544 116 221 70 13 2999.999 18_pipe/18_overflow*377/349 117 46 Upstream of Gallup Road Culvert 2999 18_overflow 349 92 23 Gallup Road Overtopping 2661 18_pipe/18_overflow*377/349 117 46 2570 118 375 116 46 1323 20 424 153 69 938 220‐322 444 168 84 Upstream of Glenmoor Pond * Discharge based on the sum of pipe and overflow discharges Discharge (cfs) HEC‐Ras Sation EPA SWMM Element Description Modified - Table B.1.1 Plum Channel Flow Path Discharge Profile Effective HEC-RAS hydraulics model/Result Corrected Effective Mapped by Anderson /Result Modeled /Result Modeled 5271 113 (313out in CE models)241 156 252 245 Upstream Study Limit 5190 NODE 23 ---------362 Pond Inflow 4872 (L)15 330 200 305 --- 4675 POND OUTFLOW J14 ---------174 Pond outflow 4277.999 C-1+115_pipe/115_overflow*214/140 167/139 290/242 187/140 Upstream of Rocky Road Culvert 4277 C-1+115_pipe/115_overflow*214/140 167/139 290/242 187/140 Rocky Road Culvert Overtopping 3993 C-1+16_pipe/16_overflow*234/160 193/160 313/253 201/142 3816 C-1+16_pipe/16_overflow*234/160 193/160 313/253 201/142 3544 (L)116 221 180 229 176 2999.999 18_pipe/18_overflow*377/349 354/327 285/258 285/257 Upstream of Gallup Road Culvert 2999 18_overflow 349 327 Gallup Road Overtopping 2661 18_pipe/18_overflow*377/349 354/327 285/285 2570 (L)118 375 352 284 281 1323 (L)20 424 406 356 356 938 (L)220-322 444 434 Upstream of Glenmoor Pond * Discharge based on the sum of pipe and overflow discharges (Surface Flow) Discharge (cfs) Effective HEC RAS - STATION EPA SWMM ELEMENT Effective SWMM Hydrology model Location Appendix J-6 Spillway Variance Request Stormwater Alternative Compliance/Variance Application City of Fort Collins Water Utilities Engineering Section A: Engineer/Owner Information Engineer Name____________________________________________Phone___________________________ Street Address_____________________________________________________________________________ City__________________________________________State________________________Zip_____________ Owner Name______________________________________________Phone___________________________ Street Address_____________________________________________________________________________ City__________________________________________State________________________Zip_____________ Section C: Alternative Compliance/Variance Information Section B: Proposed Project Information Legal description and/or address of property____________________________________________________ Project Name______________________________________________________________________________ Project/Application Number from Development Review (i.e. FDP123456)__________________________ Description of Project_______________________________________________________________________ __________________________________________________________________________________________ Existing Use (check one): ☐ residential ☐ non-residential ☐ mixed-use ☐ vacant ground Proposed Use (check one): ☐ residential ☐ non-residential ☐ mixed-use ☐ other____________________ If non-residential or mixed use, describe in detail_______________________________________________ __________________________________________________________________________________________ __________________________________________________________________________________________ State the requirement from which alternative compliance/variance is sought. (Please include applicable Drainage Criteria Manual volume, chapter and section.) What hardship prevents this site from meeting the requirement? What alternative is proposed for the site? Attach separate sheet if necessary Attach separate sheet if necessary  7200 South Alton Way Suite C400 Centennial, CO 80112 303-740-9393  Fax 303-921-7320  25188 Genesee Trail Road Suite 110 Golden, CO 80401 303-740-9393  Fax 303-921-7320  5475 Tech Center Drive Suite 235 Colorado Springs, CO 80919 719-593-2593  Fax 303-921-7320  2900 South College Avenue Suite 1A Fort Collins, CO 80525 970-491-9888  Fax 303-921-7320 VARIANCE REQUEST Date:November 18th 2024 From:Joseph Frank, PE Subject:Scenic Views and Polestar Spillway Variance Request I am writing to request a variance from the 2018 Stormwater City of Fort Collins criteria regarding the spillway requirements for Scenic Views Pond and Polestar/Happy Heart Detention pond. Specifically, the variance is for: Chapter 8, Section 3.4 – Free Board Twelve inches (12”) of freeboard is to be provided within the detention basin, measured vertically from the 100-year water surface elevation to the top of the basin, or measured from the emergency spillway elevation (if it is higher than the 100-year water surface elevation) to the top of the basin. Chapter 8, Section 3.5 – Spillway Max Flow Depth Emergency overflow depth shall be no more than six inches (6”) at the crest during the 100-year storm. The Scenic Views Pond and Polestar/Happy Heart Detention pond are located in the City of Fort Collins floodplain termed “Plum Street Flow Path” Scenic View Pond Spillway Existing condition for Scenic Views Pond: The existing spillway has a depth of 1.5 feet and width of 10 feet. The existing spillway elevation is at (5115.57 on the NAVD 88 datum) and (5112.5 on the NVGD 29 datum). The flow from the pond (349 cfs = peak pond inflow per corrected effective SWMM model) surpasses the capacity of the spillway, causing it to overflow and overtops the embankment at an approximate depth of 2.02 feet. The water then spills over the eastern portion of the retention pond for a distance of approximately 290 ft, see existing Scenic Views pond spillway section in Appendix A.1. Proposed condition: JR Engineering is proposing to modify the overflow spillway while maintaining the existing spillway elevation of 5115.57 as to not impact volume within the pond. The proposed spillway has a crest length of 51 feet and will result in an overflow depth 1.75 feet at 349 cfs, which exceeds the city's required depth of six inches. See the scenic views spillway improvement section in Appendix A.1. Justification for Variance: The proposed improvements are intended to increase the emergency overflow spillway capacity and improve the existing spillway by providing additional riprap protection. This modification will decrease the overall breadth of the floodplain, reduce the emergency overflow depth from 2.02 feet to 1.75 feet and serve as an improvement to the existing scenic views retention pond.The proposed Finished Flood Elevations (FFE) of the building directly downstream of the Scenic Views Retention facility will be set at 18-inches above the proposed base flood elevation The spillway variance is necessary to  7200 South Alton Way Suite C400 Centennial, CO 80112 303-740-9393  Fax 303-921-7320  25188 Genesee Trail Road Suite 110 Golden, CO 80401 303-740-9393  Fax 303-921-7320  5475 Tech Center Drive Suite 235 Colorado Springs, CO 80919 719-593-2593  Fax 303-921-7320  2900 South College Avenue Suite 1A Fort Collins, CO 80525 970-491-9888  Fax 303-921-7320 increase the emergency capacity and prevent overtopping of the existing embankment. Please refer to exhibits and calculations in Appendix A.1 for additional information. Polestar Detention Pond Spillway Proposed Polestar/Happy Heart Farms Spillway: The proposed spillway has a crest length of 36.8 feet and will result in an overflow depth 2.21 feet at 362 cfs (peak pond inflow per proposed SWMM model), which exceeds the city's required depth of six inches. This spillway is intended to remain in place when the ultimate regional pond is constructed which will result in an overflow depth of 1.61 feet at 221 cfs. See the Polestar detention facility spillway section in Appendix B.1. Justification for Variance: The request is to allow for the same approach as the Concept Canal Importation Master Plan for the ultimate condition by Jacobs and prevent the flow from the emergency spillway from being directed towards existing structures and homes downstream. By narrowing the spillway and allowing the overflow depth to exceed six inches, the spillway will better direct flows between houses and towards the improvements in the drainage easement to the east of the Polestar development. Refer to exhibits and calculations in Appendix B.1 for additional information.  7200 South Alton Way Suite C400 Centennial, CO 80112 303-740-9393  Fax 303-921-7320  25188 Genesee Trail Road Suite 110 Golden, CO 80401 303-740-9393  Fax 303-921-7320  5475 Tech Center Drive Suite 235 Colorado Springs, CO 80919 719-593-2593  Fax 303-921-7320  2900 South College Avenue Suite 1A Fort Collins, CO 80525 970-491-9888  Fax 303-921-7320 Appendix A.1 A Westrian Company EXISTING SCENIC VIEWS - SPILLWAY A Westrian Company SCENIC VIEWS - SPILLWAY IMPROVEMENT A Westrian Company Scenic Views Pond Broad Crested Weir Project Description Crest LengthSolve For Input Data cfs348.61Discharge ft5,117.32Headwater Elevation ft5,115.57Crest Elevation ft0.00Tailwater Elevation GravelCrest Surface Type ft20.00Crest Breadth Results ft51.0Crest Length ft1.75Headwater Height Above Crest ft-5,115.57Tailwater Height Above Crest ft^(1/2)/s2.95Weir Coefficient 1.000Submergence Factor ft^(1/2)/s2.95Adjusted Weir Coefficient ft²89.3Flow Area ft/s3.90Velocity ft54.5Wetted Perimeter ft51.02Top Width Page 1 of 127 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 2/9/2023 FlowMaster [10.03.00.03] Bentley Systems, Inc. Haestad Methods Solution CenterScenic Views Pond.fm8 Chapter 12 Storage September 2017 Urban Drainage and Flood Control District 12-33 Urban Storm Drainage Criteria Manual Volume 2 Figure 12-21. Embankment protection details and rock sizing chart (adapted from Arapahoe County)  7200 South Alton Way Suite C400 Centennial, CO 80112 303-740-9393  Fax 303-921-7320  25188 Genesee Trail Road Suite 110 Golden, CO 80401 303-740-9393  Fax 303-921-7320  5475 Tech Center Drive Suite 235 Colorado Springs, CO 80919 719-593-2593  Fax 303-921-7320  2900 South College Avenue Suite 1A Fort Collins, CO 80525 970-491-9888  Fax 303-921-7320 Appendix B.1 POLESTAR DETENTION FACILITY - SPILLWAY A Westrian Company Polestar Interim Broad Crested Weir - 1 Project Description Headwater ElevationSolve For Input Data cfs361.80Discharge ft5,107.79Crest Elevation ft0.00Tailwater Elevation GravelCrest Surface Type ft25.00Crest Breadth ft36.8Crest Length Results ft5,110.00Headwater Elevation ft2.21Headwater Height Above Crest ft-5,107.79Tailwater Height Above Crest ft^(1/2)/s2.99Weir Coefficient 1.000Submergence Factor ft^(1/2)/s2.99Adjusted Weir Coefficient ft²81.3Flow Area ft/s4.45Velocity ft41.2Wetted Perimeter ft36.80Top Width Page 1 of 127 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 8/23/2023 FlowMaster [10.03.00.03] Bentley Systems, Inc. Haestad Methods Solution CenterPolestar Pond.fm8 Ultimate Polestar - Broad Crested Weir Project Description Headwater ElevationSolve For Input Data cfs221.20Discharge ft5,107.79Crest Elevation ft0.00Tailwater Elevation GravelCrest Surface Type ft25.00Crest Breadth ft36.8Crest Length Results ft5,109.40Headwater Elevation ft1.61Headwater Height Above Crest ft-5,107.79Tailwater Height Above Crest ft^(1/2)/s2.93Weir Coefficient 1.000Submergence Factor ft^(1/2)/s2.93Adjusted Weir Coefficient ft²59.4Flow Area ft/s3.73Velocity ft40.0Wetted Perimeter ft36.80Top Width Page 1 of 127 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 8/23/2023 FlowMaster [10.03.00.03] Bentley Systems, Inc. Haestad Methods Solution CenterPolestar Pond.fm8 Chapter 12 Storage September 2017 Urban Drainage and Flood Control District 12-33 Urban Storm Drainage Criteria Manual Volume 2 Figure 12-21. Embankment protection details and rock sizing chart (adapted from Arapahoe County)  7200 South Alton Way Suite C400 Centennial, CO 80112 303-740-9393  Fax 303-921-7320  25188 Genesee Trail Road Suite 110 Golden, CO 80401 303-740-9393  Fax 303-921-7320  5475 Tech Center Drive Suite 235 Colorado Springs, CO 80919 719-593-2593  Fax 303-921-7320  2900 South College Avenue Suite 1A Fort Collins, CO 80525 970-491-9888  Fax 303-921-7320 Appendix C.1 1 Andrew Joyce From:Theodore Bender <tbender@fcgov.com> Sent:Monday, May 1, 2023 5:11 PM To:Joey Frank; Andrew Joyce; Kenneth Merritt Cc:Heidi Hansen; Dan Mogen; Matt Simpson; Ken Sampley Subject:Polestar Variance Response Attachments:Downstream Structures.jpg Hello JR Team, the correct minimum freeboard requirement at the spillway may not be the “6-inches” that we had been discussing, but -inches. This requirement is based on the need to provide 12-inches of freeboard from the (primary) 100- st bullet of the City 2018 Stormwater Criteria Manual). Typicall lower stage. The only outlet from the Scenic View Pond is the over ow spillway. did slow down our response. We understand the Polestar development project would improve the Scenic View spillway and we have taken this into We’ow this spillway. the north and south) the primary Scenic View spillway. This has been the main driver in our internal discussion to maintain safety for the future residents of this site. The result of our internal discussion is that City sta has agreed the 12-inches of freeboard, above the over ow WSEL, will not be required. Instead, we like to ask these structure directly below the Scenic Polestar Pond (Happy Heart/Eastern pond) The 6-inches of freeboard at this pond measured from the 100-yr WSE to the top of the pond embankment is approved. The main concern at this pond is that we not direct ow from the emergency spill towards any As we discussed in the past, we asked our master planning consultant to narrow up the conceptual design weir cross- The full master planned improvement at The proposed Polestar spillway weir dimensions are acceptable if the hydraulics show these exi are not impacted. As a part of the hydraulics phase of the CLOMR, please focus on this area and provide a Scenic Views Pond (Western pond) City sta The 6- of freeboard suggested at this pond measured from the 100-yr WSE to the top of the pond embankment is 2 acceptable.-inches of freeboard from the highest adjacent BFE for the structures immediately east (downstream) of the Scenic View pond (image This BFE would be CLOMR. Because these structures will be placed downstream of the primary outlet to this pond, we feel this Our decision is grounded in public safety and the safety of the new residents downstream of this spillway. Scenic View Pond in your analysis. We will review this as we This is a complicated project in a high ood risk area. This project is more complicated than other CLOMR request both the hydrology and hydraulics for this site, while most CLOMRs only propose to change the hydraulics. Please reach out if you’d like to discuss. We are happy to chat further. -TRB Theodore R. Bender, PE, CFM Stormwater Engineering Manager Master Planning and Floodplain Management 700 Wood Street Fort Collins, CO 80522-0580 (970) 221-6503 tbender@fcgov.com  7200 South Alton Way Suite C400 Centennial, CO 80112 303-740-9393  Fax 303-921-7320  25188 Genesee Trail Road Suite 110 Golden, CO 80401 303-740-9393  Fax 303-921-7320  5475 Tech Center Drive Suite 235 Colorado Springs, CO 80919 719-593-2593  Fax 303-921-7320  2900 South College Avenue Suite 1A Fort Collins, CO 80525 970-491-9888  Fax 303-921-7320 Appendix D.1 23 APPENDIX F – MAPS · · · · · · ELIZABETH ST PLUM STOVE R L A N D T R ORCHARD PL Know what's below. before you dig.Call R A W e s t r i a n C o m p a n y LO C U S T GR O V E DR I V E W. ORCHARD PL PO L E S T A R W A Y POLESTAR DETENTION POND SEE SHEET 36 SEE SHEET 37 W. PLUM ST A W e s t r i a n C o m p a n y Know what's below. before you dig.Call R ELIZABETH ST PLUM STOVE R L A N D T R ORCHARD PL · · · · · · W. ORCHARD PL PO N O W A Y KO K U A C O U R T HOKU LANE MELE LANE W. P L U M S T PO L E S T A R W A Y LO C U S T G R O V E D R I V E A W e s t r i a n C o m p a n y ELIZABETH ST PLUM STOVE R L A N D T R ORCHARD PL Know what's below. before you dig.Call R · · · · · · PO N O W A Y KO K U A C O U R T OH A N A C I R C L E W. P L U M S T HA P P Y H E A R T W A Y W. PLUM ST Know what's below. before you dig.Call R ELIZABETH ST PLUM STOV E R L A N D T R ORCHARD PL A W e s t r i a n C o m p a n y W PLUM ST PO L E S T A R WA Y LO C U S T GR O V E D R I V E W. ORCHARD PL 24 APPENDIX G –LID EXHIBIT ELIZABETH ST PLUM STOV E R L A N D T R ORCHARD PL Know what's below. before you dig.Call R LID/WQ TREATMENT A W e s t r i a n C o m p a n y W. ORCHARD PL LO C U S T GR O V E D R I V E W PLUM ST PO L E S T A R W A Y