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POWERHOUSE 2 - FDP220015 - SUBMITTAL DOCUMENTS - ROUND 1 - DRAINAGE REPORT (2)
FINAL DRAINAGE REPORT AND EROSION CONTROL REPORT POWERHOUSE 2 FORT COLLINS, COLORADO December 14, 2022 NORTHERNENGINEERING.COM 970.221.4158 FORT COLLINS GREELEY This Drainage Report is consciously provided as a PDF. Please consider the environment before printing this document in its entirety. When a hard copy is necessary, we recommend double-sided printing. NORTHERNENGINEERING.COM | 970.221.4158 FINAL DRAINAGE REPORT: POWERHOUSE 2 FORT COLLINS | GREELEY COVER LETTER December 14, 2022 City of Fort Collins Stormwater Utility 700 Wood Street Fort Collins, CO 80521 RE: FINAL DRAINAGE AND EROSION CONTROL REPORT FOR POWERHOUSE 2 Dear Staff: Northern Engineering is pleased to submit this Final Drainage and Erosion Control Report for your review. This report accompanies the combined Project Development Plan (PDP) submittal for the proposed Powerhouse 2 development. This report has been prepared in accordance with the Fort Collins Stormwater Criteria Manual (FCSCM) and serves to document the stormwater impacts associated with the proposed Powerhouse 2 development. We understand review by the City of Fort Collins is to assure general compliance with standardized criteria contained in the FCSCM. If you have any questions as you review this report, please feel free to contact us. Sincerely, NORTHERN ENGINEERING SERVICES, INC. CARLOS ORTIZ GARCIA AUSTIN SNOW, PE Project Engineer Project Engineer NORTHERNENGINEERING.COM | 970.221.4158 FINAL DRAINAGE REPORT: POWERHOUSE 2 FORT COLLINS | GREELEY TABLE OF CONTENTS TABLE OF CONTENTS GENERAL LOCATION AND DESCRIPTION .......................................................... 1 DRAIN BASINS AND SUB-BASINS ..................................................................... 6 DRAINAGE DESIGN CRITERIA .......................................................................... 6 DRAINAGE FACILITY DESIGN ........................................................................... 8 CONCLUSIONS ............................................................................................ 12 REFERENCES .............................................................................................. 13 TABLES AND FIGURES FIGURE 1 – VICINITY MAP .................................................................................................1 FIGURE 2 – AERIAL PHOTOGRAPH ...................................................................................2 FIGURE 3 – PROPOSED SITE PLAN ...................................................................................3 FIGURE 4 – AREA FLOODPLAIN MAPPING ........................................................................3 FIGURE 5 – FOUNDATION DETAIL ....................................................................................4 APPENDICES APPENDIX A – HYDROLOGIC COMPUTATIONS APPENDIX B – DETENTION POND COMPUTATION APPENDIX C – HYDRAULIC COMPUTATIONS APPENDIX D – EROSION CONTROL REPORT APPENDIX E – PRELIMINARY LID DESIGN INFORMATION APPENDIX F – SUPPORT DOCUMENTS, PREVIOUS STUDIES AND USDA SOILS REPORT MAP POCKET DR-A – EXISTING VS. PROPOSED IMPERVIOUS AREA – BASIN A DR1 – POWER HOUSE 2 DRAINAGE EXHIBIT; (NORTHERN ENGINEERING) NORTHERNENGINEERING.COM | 970.221.4158 FINAL DRAINAGE REPORT: POWERHOUSE 2 FORT COLLINS | GREELEY 1 | 12 GENERAL LOCATION AND DESCRIPTION A. LOCATION Vicinity Map The Powerhouse 2 site is located in the Southwest Quarter of Section 1, Township 7 North, Range 69 West of the 6th Principal Meridian, City of Fort Collins, County of Larimer, State of Colorado. The project site (refer to Figure 1) is bordered to the north by the Lake Canal, to the south by East Vine Drive to the east by Jerome Street, and to the west by N. College Avenue. B. DESCRIPTION OF PROPERTY The Powerhouse 2 site is comprised of roughly ±4.97 acres. The site is currently occupied by three buildings as well as concrete sidewalks, open areas, gravel parking areas, and ±48,482 square feet of asphalt. The existing imperviousness of the site is 54%. An exhibit for existing versus proposed imperviousness is provided in the Map Pocket section. The existing ground slopes with a mild to moderate grade (i.e., 0.5 – 2.0±%) Figure 1 – Vicinity Map NORTHERNENGINEERING.COM | 970.221.4158 FINAL DRAINAGE REPORT: POWERHOUSE 2 FORT COLLINS | GREELEY 2 | 12 through the interior to the south across flat grades into East Vine Drive. The drainage continues through the Poudre River Whitewater Park and on to the Cache La Poudre River. A soils report (Project No. FC10223-125) was completed by CTL Thompson, Inc. on March 14, 2022. The report contains the results of a complete geotechnical subsurface exploration as well as pertinent geotechnical recommendations. There are two major drainageways close to the site. The Lake Canal is located on the north side of the site and the Cache la Poudre River is located approximately 550 feet south of the site. The proposed project site consists of one building. Other proposed improvements include concrete and permeable paver drive aisle, gravel parking, walkways, a courtyard, landscape, and open space areas. The proposed imperviousness of the site is 56%. An existing and proposed imperviousness exhibit is provided in the Map Pocket section. Figure 3 shows the proposed site plan. Figure 2 – Aerial Photograph NORTHERNENGINEERING.COM | 970.221.4158 FINAL DRAINAGE REPORT: POWERHOUSE 2 FORT COLLINS | GREELEY 3 | 12 C. FLOODPLAIN The Powerhouse 2 project is located within a FEMA Special Flood Hazard Area of the Cache la Poudre River (Poudre River). Most of this area is designated as With Base Flood Elevation (BFE) or Depth in Zone AE on FIRM Panel 08069C0997G, effective June 17, 2008. The floodplain from the Whitewater Park Letter of Map Revision (LOMR) Case No. 20-08-0643P, effective June 25, 2021, supersedes the current FEMA RiskMap. An Additional LOMR became effective on November 19, 2021, Case No. 21-08-1189X, to correct the Flood Zone designations for some of the islands (Zone X Shaded) within the Whitewater Park LOMR. Zone X Shaded is due to the Figure 4 – Area Floodplain Mapping Figure 3 – Proposed Site Plan NORTHERNENGINEERING.COM | 970.221.4158 FINAL DRAINAGE REPORT: POWERHOUSE 2 FORT COLLINS | GREELEY 4 | 12 500-yr floodplain. Most of the property falls inside the regulated 100-year floodplain. Chapter 10 of the City of Fort Collins Municipal Code regulates critical facilities within this Flood Hazard Zone. It should be noted FEMA, as part of RiskMap, is currently remapping the Poudre River. Anderson Consulting Engineers (ACE) will provide the updated Floodplain modeling, mapping, and report for the site when completed. It is assumed a portion of the project site will continue to be located within the updated 100- year floodplain. To ensure the proposed buildings have adequate flood protection, the finished floors and all ductwork, heating, ventilation, electrical systems, etc., will be elevated 24-inches above the effective Base Flood Elevation (BFE). This elevation is known as the Regulatory Flood Protection Elevation (RFPE). The RFPE = BFE + 24 inches. The solar panels and the electric vehicle charging components in the parking lot shall be installed above the RFPE or have floodproofing as required by Chapter 10 of the City of Fort Collins Municipal Code. A minimum of 24-inches of freeboard will be provided from base (100-year) flood elevation (BFE). This freeboard level will be applied to either the design of finished floor elevations or the minimum level of floodproofing measures The vertical datum utilized for site survey work is the City of Fort Collins Benchmark # 1-00 (Elevation=4968.74); NAVD 88. Furniture or site components shall be securely anchored with a system of 4" lag bolts epoxied into ground base concrete or stone with straps and/or chains secured to elements to prevent flotation. Anchoring details will be supplied at the time of the floodplain use permit. A floodplain use permit will be required for the building structure and each site construction element in the floodplain. The floodplain use permit for the building will be approved at the time of the building permit application. A floodplain use permit and no rise certification is required prior to performing any work within the floodplain (i.e., curb cut removal, landscaping). A post-construction elevation certificate including components like transformer, yards, EV. charging stations, solar panel components, elevator, HVAC equipment, emergency vehicle Figure 5 – Foundation Detail NORTHERNENGINEERING.COM | 970.221.4158 FINAL DRAINAGE REPORT: POWERHOUSE 2 FORT COLLINS | GREELEY 5 | 12 access gate, other electrical and mechanical systems, etc. must be approved before a certificate of occupancy will be issued. All elevators installed below the RFPE in the project will comply with FEMA NFIP technical bulletin on June 4, 2019, and the 2021 IBC. An Emergency Response and Preparedness Plan (ERPP) will be required by the City of Fort Collins prior to a floodplain or building permit being issued. Outdoor classrooms and informal outdoor gathering space will be used for site tours and outdoor learning. These spaces will be constructed using large boulders and crusher-fine surfacing. Critical facilities are prohibited in the floodplain, including hazardous material, government services, essential services and at-risk population critical facilities. This includes schools and after school programs/day camps for grades K-12. Per the “Hazardous Material Storage and Handling of Flammable Materials” memo by Bryan Wilson provided in Appendix F, the quantities listed below and the removal of hydrogen storage from the site will remove the designation of a "Critical Facility," as defined by Chapter 10 of City Code, from the project. Material storage restrictions will be removed with the approval of the LOMR. The following outlines the handling and storage processes of hydrogen for research procedures anticipated at the proposed Powerhouse 2 facility: • Hydrogen produced by hydrolysis or similar method will be disposed of as produced via venting outdoors (as per any code requirements), burned outdoors in a non-visible flare, consumed by fuel cell or similar device. • Onsite storage of hydrogen will remain at or below quantities regulated by international fire safety code or "household levels." • Hydrogen fueled vehicles, such as automobiles, light and medium duty trucks, and transit buses, will be tested onsite and adhere to all fire safety codes and DOT regulations regarding hydrogen fueled vehicles. No vehicles will be stored outside overnight per the floatable materials requirements in Chapter 10 of City Code. • H2 storage tanks will remain at Powerhouse I until approval of the LOMR. Flammable Materials: • Acetylene 1 commercial cylinder at 300 or less std. cu. ft. volume. • Oxygen 1 commercial cylinder at 300 or less std. cu. ft. volume. Non-Reactive Gases: • Compressed Air 500 gal. tank • Compressed Nitrogen 2000 L. Cryogenic Tank, Liquid • Compressed Argon 2000 L. Cryogenic Tank, Liquid • Compressed Helium <20 - 300 std. cu ft, steel cylinders • Compressed Argon <20 - 300 std. cu ft, steel cylinders • Compressed CO2 <20 - 300 std. cu ft, steel cylinders The proposed Powerhouse 2 building is projected to house several types of organizations: NORTHERNENGINEERING.COM | 970.221.4158 FINAL DRAINAGE REPORT: POWERHOUSE 2 FORT COLLINS | GREELEY 6 | 12 retail, private companies working in the energy industry, and Colorado State University (CSU) functions relating to sponsored research. The CSU space will be assigned to researchers to conduct sponsored research for industry and government (local, city, state and federal) sponsors. These spaces will not be used for traditional educational functions such as classroom instruction or laboratory instruction. While university employees (researchers, staff, and student employees) will be using the space they will not be engaged in instructional activities. Government services facilities include essential structures such as dormitories, offices, classrooms, and laboratories for public higher education facilities. Powerhouse 2 will not be used for dormitory housing. Nor will it have instructional classrooms and the laboratory and office spaces will be used solely for sponsored research activities. Given this definition and purposes, Powerhouse 2 should not be classified as a government services facility per Chapter 10 of City Code and the restrictions associated with this designation. Regarding Government Service Critical Facilities and Hazardous Material Critical Facilities, the applicant has provided further explanation of the planned uses that will occur prior to the Letter of Map Revision becoming effective. See Appendix F for letters from the applicant. DRAIN BASINS AND SUB-BASINS A. MAJOR BASIN DESCRIPTION Powerhouse 2 is located in the Cache la Poudre River Basin, a major tributary to the South Platte River. The river is located in Larimer and Weld Counties, with a small portion of the drainage basin extending into southern Wyoming. Passing through Fort Collins, the Poudre River corridor provides stormwater drainage from various contributing city drainage basins. Floodplain restrictions have limited the amount of building in the floodplain, resulting in lower development density. This lower density, combined with sensitivities to the natural environment, has resulted in a high concentration of parks and open spaces along the river corridors. B. SUB-BASIN DESCRIPTION The subject property historically drains overland through the interior to the south across flat grades. Runoff from the site has historically been routed to an existing pond/wetland on the south side of Vine Drive. The project site was a part of a previous drainage study in this area, "Drainage, Water Quality and Erosion Control Report for the Poudre River Whitewater Park Project" by Anderson Consulting Engineers, Inc., dated June 6, 2017. Within the drainage study, Powerhouse 2 is associated with Basin 9, with a contributing area of 4.68 acres and an assumed fully-developed imperviousness of 85%. DRAINAGE DESIGN CRITERIA A. REGULATIONS There are no optional provisions outside of the FCSCM proposed with the proposed project. B. DEVELOPMENT CRITERIA REFERENCE AND CONSTRAINTS In June 2017, Anderson Consulting Engineers, Inc. (ACE), per the direction of the City of Fort Collins Stormwater staff, provided a Stormwater Management Model (SWMM) model for a fully- developed condition scenario to evaluate the size of the proposed project infrastructure for the NORTHERNENGINEERING.COM | 970.221.4158 FINAL DRAINAGE REPORT: POWERHOUSE 2 FORT COLLINS | GREELEY 7 | 12 Poudre River Whitewater Park project. The objective of this modeling was to generate a conceptual drainage plan for future improvements. In the final modeling, Subbasins 8, 9, 10, and 11 are related to the site. ACE considered conceptual detention ponds for the privately owned properties located north of East Vine Drive (Subbasins 9 and 11) to detain and release fully-developed 100-year flows at a 2-year historical rate. For the Powerhouse 2 project, the corresponding basin is Subbasin 9 of the drainage study. An excerpt from the "Drainage, Water Quality and Erosion Control Report for the Poudre River Whitewater Park Project" drainage report is included in Appendix F. In order to bring Powerhouse 2 into compliance with the current land use code and stormwater criteria, 75% of all newly added impervious areas will be treated by Low Impact Development (LID) techniques. The remaining water quality will be provided in the proposed detention pond. C. HYDROLOGICAL CRITERIA The City of Fort Collins Rainfall Intensity-Duration-Frequency Curves, as depicted in Figure 3.4-1 of the FCSCM, serve as the source for all hydrologic computations associated with the proposed development. Tabulated data contained in Table 3.4-1 was utilized for Rational Method runoff calculations. The Rational Method was employed to compute localized stormwater runoff utilizing coefficients contained in Tables 3.2-1 and 3.2-2 of the FCSCM. Two separate design storms were utilized to address distinct drainage scenarios. The first event analyzed is the "Minor" or "Initial" storm, which has a two-year recurrence interval. The second event considered is the "Major" storm, which has a 100-year recurrence interval. No other assumptions or calculation methods were used for this development that is not referenced by the current City of Fort Collins criteria. D. HYDRAULIC CRITERIA As previously noted, the subject property maintains historical drainage patterns. All drainage facilities proposed with the project are designed in accordance with the criteria outlined in the FCSCM and/or the Urban Drainage and Flood Control District (UDFCD) Urban Storm Drainage Criteria Manual. As discussed above, the subject property is located in a 100-year floodplain. The proposed project does not propose to modify any natural drainageways. E. MODIFICATIONS OF CRITERIA Due to site topographic constraints, it is effectively impossible to achieve 12” of freeboard in the site’s stormwater detention facility (to the top of the emergency spillway). The project includes a variance for the first paragraph of Section 3.4 of the FCSCM which spells out the requirement for 12” of freeboard from the 100-year water surface elevation (WSE) to the top of the emergency spillway. 12” of freeboard between the 100-year WSE to the minimum opening elevations of buildings on-site is provided as required. NORTHERNENGINEERING.COM | 970.221.4158 FINAL DRAINAGE REPORT: POWERHOUSE 2 FORT COLLINS | GREELEY 8 | 12 F. STORM MANAGEMENT STRATEGY The overall stormwater management strategy employed with the Powerhouse 2 development utilizes the "Four Step Process" to minimize adverse impacts of urbanization on receiving waters. The following describes how the proposed development has incorporated each step. Step 1 – Employ Runoff Reduction Practices. The first consideration taken in trying to reduce the stormwater impacts of this development is the site selection itself and the selection of developable areas on the site. The Powerhouse 2 development aims to reduce runoff peaks, volumes, and pollutant loads from frequently occurring storm events (i.e., water quality (i.e., 80th percentile) and two-year storm events). Site constraints limit the possible LID techniques; however, rain gardens have been provided for this site as LID techniques for storm quality management. Step 2 – Implement Best Management Practices (BMPs) that provide a Water Quality Capture Volume (WQCV) with slow release. The efforts taken in Step 1 will help to minimize excess runoff from frequently occurring storm events; however, the development still generates additional stormwater runoff beyond historical conditions. The primary water quality treatment and volume control will occur in the detention pond. Step 3 – Stabilize Drainageways. As stated in Section I.A.3, the Lake Canal is located on the north side of the site; however, no changes are proposed to Lake Canal with this project. While this step may not seem applicable to the Powerhouse 2 development, the proposed project indirectly helps stabilize drainageways. Once again, site selection has a positive effect on stream stabilization. Step 4 – Implement Site Specific and Other Source Control BMPs. This step typically applies to industrial and commercial developments. DRAINAGE FACILITY DESIGN A. GENERAL CONCEPT The main objectives of the project drainage design are to maintain existing drainage patterns and ensure no adverse impacts to any adjacent properties. A total combined release rate of 16.77 cubic feet per second (cfs) has been determined for the proposed detention facility. This release rate has been grandfathered and agreed to by City staff. The methodology accounts for existing impervious areas on the site, which will be allowed to be released at the 100-year historical rate. There is a combined 1.32 acres of existing impervious area within the development site, which drains to East Vine Drive. The 100-year discharge from this impervious area is 13.11 cfs. There is a combined 3.66 acres of existing pervious area within the development site, which also drains to East Vine Drive. A 2-year discharge of 3.65 cfs has been calculated from this pervious area. The sum of "grandfathered" existing impervious areas discharging into East Vine Drive combined with 2-year existing pervious areas is 16.77 cfs, which is considered the allowable peak release rate for the site. We have subtracted the 100-year undetained discharge computed from Basins 5, 7, 8, 10, 11, and 12 (3.68 cfs total) for an allowable release rate of 13.09 cfs (16.77 cfs -3.68 cfs). However, the detention pond calculations are limited to a release rate of 11.5 cfs due to the capacity of the proposed 12" outlet pipe. The previous Conceptual Design from Anderson Consulting Engineers, Inc. included an 18" RCP outlet pipe. Upon checking the conceptual design, it was discovered that the pipe did not have NORTHERNENGINEERING.COM | 970.221.4158 FINAL DRAINAGE REPORT: POWERHOUSE 2 FORT COLLINS | GREELEY 9 | 12 sufficient cover on the north flowline of Vine Drive; therefore, the pipe diameter was reduced to 2-12" HDPE pipes with a lower release rate of 8.5 cfs for Outfall A and a 12" DIP with a release rate of 3.0 cfs for Outfall B. We have used this 11.5 cfs value (8.5 cfs + 3.0 cfs) when sizing our detention pond. Onsite detention and water quality treatment for the Powerhouse 2 project will be provided within the detention pond and rain gardens. A temporary piezometer was installed approximately 25' north of the proposed detention pond. On July 29, 2022, the groundwater reading was at 5 feet below existing grade, which is approximately 1.2' below the proposed detention pond outlet. While it is desired to have more separation between the pond bottom and groundwater, the pond bottom has been elevated as much as possible and the outfall pipe is as shallow as it can go. An underdrain has been proposed in the detention pond to help mitigate the infiltration of water from the detention pond into the groundwater. Undulations have been added to the pond bottom, so most of the detention pond is 18” or more above the groundwater elevation, with more than half being 24” or more. LID treatment requirements will be met using rain gardens on the north and south sides of the project, thereby meeting the requirement of at least 75% of all newly added impervious areas. As mentioned above, Anderson Consulting Engineers, Inc. included East Vine Drive and the Powerhouse 2 site in their drainage study for the Poudre River Whitewater Project. Their Site Map can be found in Appendix F. That study dictated that flows from Vine, Jerome, and the parcel at the northeast corner of the Jerome/Vine intersection be conveyed along Vine to an inlet that would then convey flows south using the proposed 18 RCP and on to the downstream detention and water quality features. Our proposed drainage design follows this approach but uses a 2-12" HDPE pipeS, as noted above. B. SPECIFIC DETAILS The detention volume required for the site is 0.26 acre-feet. This volume was calculated using the FAA Method. City Code requires LID treatment for all projects. This project proposes meeting the requirement by using rain gardens as a LID technique. The rain gardens will capture the majority of the water quality volume (WQCV) for the entire site, providing a total volume of 3,139 cubic feet. This configuration will treat at least 75% of the new impervious area. The project is also including permeable pavers and gravel parking areas throughout the project. While these don't count towards the official LID calculation, they achieve similar outcomes and further enhance stormwater treatment on the site. The Powerhouse 2 site has been broken into onsite sub-basins for design purposes. Anticipated drainage patterns for proposed drainage basins are described below. Basins 1a to 1d Basin 1a to1d, approximately 2.41 acres, consists of building, asphalt, sidewalk, paver, gravel, open areas, and solar panel rooftops in the parking area. Runoff from the basin will sheet flow north into a swale along the north property line. The swale will discharge into the rain garden and then to Basin 6. NORTHERNENGINEERING.COM | 970.221.4158 FINAL DRAINAGE REPORT: POWERHOUSE 2 FORT COLLINS | GREELEY 10 | 12 Basin 2 Basin 2, approximately 0.61 acres, consists of asphalt, sidewalk, gravel, open areas, and solar panel rooftops in the parking lot. Runoff from the basin will sheet flow to a proposed curb opening located on the southeast side of the parking area and then to Basin 6. Basin 3a to 3c Basins 3a to 3c, approximately 0.45 acres, consists of a building, sidewalk, and open areas. Runoff from the basin will convey flows via sheet flow and roof leaders to a rain garden located on the south and then to Basin 6. Basins 4 Basin 4, approximately 0.29 acres, consists of asphalt, sidewalk, and landscape areas. Runoff from the basin will convey flows via sheet flow to a proposed Curb cut and then to Basin 6. Basins 5 & 7 Basin 5, approximately 0.16 acres, and Basin 7, approximately 0.011 acres, consists of sidewalk and landscape areas. Runoff from the basins will convey flows via sheetflow to a proposed area inlet located on East Vine Drive, then routed to the Whitewater Park detention pond. Basin 6 Basin 6, approximately 0.36 acres, consists of open space. This basin is the onsite detention pond. Basin 8 and Co1 Basin 8, approximately 0.12 acres, and Basin Co1, approximately 0.43 acres, consists of asphalt, sidewalks, and landscape. Runoff from the basins will drain via sheet flow to the curb and gutter along North College Avenue, then into an existing inlet in sump. The runoff will follow existing drainage patterns. Basin 9 Basin 9, approximately 0.14 acres, is an offsite basin and consists of open space. Runoff from the basin will be conveyed through the north rain garden and then through Basin 6 without being detained. Basins 10 and 11 Basin 10, approximately 0.03 acres, and Basin 11, approximately 0.05 acres, consist of open space. Runoff from the basins will drain via sheet flow north to Lake Canal. The areas are outside the limits of disturbance and will continue to drain to the ditch as they currently do. Basin 12 Basin 12, approximately 0.14 acres, consists of sidewalks and landscape. Runoff from the basin will drain via sheet flow east to Jerome Street and follow existing drainage patterns to a proposed area inlet located on East Vine Drive. Runoff from the basin will be routed to the Whitewater Park detention pond. Basins W8 & W10 Basin W8, approximately 0.63 acres, and Basin 10, approximately 1.50 acres, are part of the "Drainage, Water Quality and Erosion Control Report for the Poudre River Whitewater Park Project" Drainage Study. Runoff from the basins will follow the assumed fully-developed conceptual design path from the drainage study. The runoff will be routed to a proposed area inlet on East Vine Drive and then to the Whitewater Park detention pond. NORTHERNENGINEERING.COM | 970.221.4158 FINAL DRAINAGE REPORT: POWERHOUSE 2 FORT COLLINS | GREELEY 11 | 12 Basin W11 Basin W11, approximately 0.89 acres, is part of the "Drainage, Water Quality and Erosion Control Report for the Poudre River Whitewater Park Project" Drainage Study. Runoff from the basin will follow the assumed fully-developed conceptual design path from the drainage study and will be routed via storm drain to Whitewater Park detention pond in the future when the parcel is developed. A full-size copy of the Drainage Exhibit can be found in the Map Pocket at the end of this report. NORTHERNENGINEERING.COM | 970.221.4158 FINAL DRAINAGE REPORT: POWERHOUSE 2 FORT COLLINS | GREELEY 12 | 12 C. LID SUMMARY Powerhouse 2 is providing a rain garden to treat a portion of the north area of the site that will see the highest runoff rate and contains portions of the building, concrete drive aisles, sidewalk, permeable pavers, gravel parking, landscape areas, and solar panel rooftops in a portion of the parking lot (Basin 1). Powerhouse 2 is providing a rain garden to treat a portion of the southwest area of the site, which contains a portion of the building, sidewalks, and open areas (Basin 3). Powerhouse 2 On-Site LID Treatment Project Summary Total Impervious Area 134,735 sf Target Treatment Percentage 75% Minimum area to be Treated by LID measures 101,051 sf Treated Impervious Areas by Treatment Method Rain Garden 86,629 Sf Gravel Paving 31,096 Sf Total Treated Impervious Areas 117,725 sf Percent Total Project Area Treated 87.4% CONCLUSIONS A. COMPLIANCE WITH STANDARDS The drainage design proposed with the Powerhouse 2 project complies with the City of Fort Collins Stormwater Criteria Manual. The drainage design proposed for this project complies with the "Drainage, Water Quality and Erosion Control Report for the Poudre River Whitewater Park Project" Drainage Study. The drainage design proposed with this project complies with the Cache la Poudre River Basin requirements. The proposed project complies with the regulation from Chapter 10 of the City Code. These includes: -The Building finished floors and all ductwork, heating, ventilation, electrical systems, etc., will be elevated 24-inches above the effective Base Flood Elevation (BFE). -Any items located in the floodplain that can float (e.g., picnic tables, bike racks, etc.) must be anchored. -An Emergency Response and Preparedness Plan (ERPP) will be required by the City of Fort Collins prior to a floodplain or building permit being issued -Critical facilities are prohibited in the floodplain, including hazardous material, government services, essential services and at-risk population critical facilities. this includes schools and after school programs/day camps for grades k-12. NORTHERNENGINEERING.COM | 970.221.4158 FINAL DRAINAGE REPORT: POWERHOUSE 2 FORT COLLINS | GREELEY 13 | 12 REFERENCES 1. City of Fort Collins Landscape Design Guidelines for Stormwater and Detention Facilities, November 5, 2009, BHA Design, Inc. with City of Fort Collins Utility Services. 2. Fort Collins Stormwater Criteria Manual, City of Fort Collins, Colorado, adopted by Ordinance No. 174, 2011, and referenced in Section 26-500 (c) of the City of Fort Collins Municipal Code. 3. Larimer County Urban Area Street Standards, Adopted January 2, 2001, Repealed and Reenacted, Effective October 1, 2002, Repealed and Reenacted, Effective April 1, 2007. 4. Soils Resource Report for Larimer County Area, Colorado, Natural Resources Conservation Service, United States Department of Agriculture. 5. Urban Storm Drainage Criteria Manual, Volumes 1-3, Urban Drainage and Flood Control District, Wright-McLaughlin Engineers, Denver, Colorado, Revised April 2008. 6. Drainage, Water Quality and Erosion Control Report for the Poudre River Whitewater Park Project dated June 6, 2017, by Anderson Consulting Engineers, Inc. NORTHERNENGINEERING.COM | 970.221.4158 FINAL DRAINAGE REPORT: POWERHOUSE 2 FORT COLLINS | GREELEY APPENDIX APPENDIX A HYDROLOGIC COMPUTATIONS Runoff Coefficient 1 Percent Impervious 1 Project: Location: 0.95 100% Calc. By: 0.95 90% Date: 0.50 40% 0.50 40% 0.20 2% 0.20 2% Basin ID Basin Area (sq.ft.) Basin Area (acres) Asphalt, Concrete (acres) Rooftop (acres) Gravel (acres) Undeveloped: Greenbelts, Agriculture (acres) Lawns, Clayey Soil, Flat Slope < 2% (acres) Percent Impervious C2*Cf Cf = 1.00 C5*Cf Cf = 1.00 C10*Cf Cf = 1.00 C100*Cf Cf = 1.25 Imp. Areas lot 2 & 3 30,613 0.70 0.60 0.10 0.00 0.00 0.00 99% 0.95 0.95 0.95 1.00 Perv. Areas lot 2 & 3 20,004 0.46 0.00 0.00 0.32 0.00 0.14 28% 0.41 0.41 0.41 0.51 Imp. Areas lot 4 26,797 0.62 0.51 0.11 0.00 0.00 0.00 98% 0.95 0.95 0.95 1.00 Perv. Areas lot 4 139,212 3.20 0.00 0.00 3.08 0.00 0.11 39% 0.49 0.49 0.49 0.61 H1 216,626 4.97 1.11 0.20 3.40 0.00 0.25 54% 0.60 0.60 0.60 0.76 1a 2,026 0.05 0.05 0.00 0.00 0.00 0.00 100% 0.95 0.95 0.95 1.00 1b 3,533 0.08 0.00 0.08 0.00 0.00 0.00 90% 0.95 0.95 0.95 1.00 1c 21,004 0.48 0.00 0.48 0.00 0.00 0.00 90% 0.95 0.95 0.95 1.00 1d 78,246 1.80 0.84 0.00 0.14 0.00 0.82 51% 0.57 0.57 0.57 0.72 2 26,739 0.61 0.40 0.00 0.32 0.00 -0.10 85% 0.84 0.84 0.84 1.00 3a 268 0.01 0.00 0.01 0.00 0.00 0.00 90% 0.95 0.95 0.95 1.00 3b 17,171 0.39 0.03 0.33 0.00 0.00 0.03 84% 0.90 0.90 0.90 1.00 3c 2,128 0.05 0.04 0.01 0.00 0.00 0.01 89% 0.87 0.87 0.87 1.00 4 12,707 0.29 0.13 0.00 0.00 0.00 0.16 46% 0.53 0.53 0.53 0.67 6 15,560 0.36 0.00 0.00 0.00 0.00 0.36 2% 0.20 0.20 0.20 0.25 5 7,016 0.16 0.07 0.00 0.00 0.00 0.09 44% 0.53 0.53 0.53 0.66 7 4,982 0.11 0.06 0.00 0.00 0.00 0.05 53% 0.59 0.59 0.59 0.74 8 5,214 0.12 0.04 0.00 0.00 0.00 0.08 35% 0.45 0.45 0.45 0.56 9 5,990 0.14 0.00 0.00 0.00 0.00 0.14 2% 0.20 0.20 0.20 0.25 10 1,258 0.03 0.00 0.00 0.00 0.00 0.03 2% 0.20 0.20 0.20 0.25 11 2,361 0.05 0.00 0.00 0.00 0.00 0.05 2% 0.20 0.20 0.20 0.25 12 5,961 0.14 0.07 0.00 0.00 0.00 0.06 54% 0.60 0.60 0.60 0.74 Co1 18,886 0.43 0.31 0.00 0.00 0.00 0.12 72% 0.74 0.74 0.74 0.92 W8 27,443 0.63 Information taken from "Drainage, Water Quality and Erosion Control Report for Poudre River Whitewater Park" 90% Where: Length (ft) Elev Up Elev Down Slope (%) Ti 2-Yr (min) Ti 10-Yr (min) Ti 100-Yr (min) Length (ft) Elev Up Elev Down Slope (%) Surface n Flow Area 3 (sq.ft.) WP 3 (ft) R (ft) V (ft/s) Tt (min) Tc 2-Yr (min) Tc 100-Yr (min) imp. areas lot 2 & 3 Imp. Areas lot 2 & 3 119 65.00 64.17 0.70% 3.45 3.45 2.30 327 64.17 61.50 0.82% Swale (8:1) 0.04 8.00 16.12 0.50 2.41 2.26 5.71 5.00 perv. areas lot 2 & 3 Perv. Areas lot 2 & 3 119 65.00 64.17 0.70% 15.89 15.89 13.54 327 64.17 61.50 0.82% Swale (8:1) 0.04 8.00 16.12 0.50 2.41 2.26 12.48 12.48 imp. areas lot 4 Imp. Areas lot 4 119 63.75 61.60 1.81% 2.51 2.51 1.67 181 61.60 60.41 0.66% Swale (8:1) 0.04 8.00 16.12 0.50 2.16 1.39 5.00 5.00 perv. areas lot 4 Perv. Areas lot 4 119 63.75 61.60 1.81% 10.23 10.23 8.18 181 61.60 60.41 0.66% Swale (8:1) 0.04 8.00 16.12 0.50 2.16 1.39 11.62 9.57 1a 1a 27 69.00 68.82 0.66% 1.68 1.68 1.12 20 68.82 68.73 0.44% Swale (8:1) 0.04 8.00 16.12 0.50 1.78 0.19 5.00 5.00 1b 1b ASSUMED A TIME OF CONCENTRATION OF 5 MINUTE FOR ROOF 5.00 5.00 1c 1c ASSUMED A TIME OF CONCENTRATION OF 5 MINUTE FOR ROOF 5.00 5.00 1d 1d 85 69.00 64.32 5.48% 5.16 5.16 3.76 229 60.50 60.41 0.04% Swale (8:1) 0.04 8.00 16.12 0.50 0.53 7.24 11.75 11.00 2 2 75 62.52 61.32 1.60% 3.57 3.57 1.38 228 61.32 60.18 0.50% Swale (8:1) 0.04 8.00 16.12 0.50 1.89 2.01 5.58 5.00 3a 3a ASSUMED A TIME OF CONCENTRATION OF 5 MINUTE FOR ROOF 5.00 5.00 3b 3b ASSUMED A TIME OF CONCENTRATION OF 5 MINUTE FOR ROOF 5.00 5.00 3c 3c ASSUMED A TIME OF CONCENTRATION OF 5 MINUTE FOR ROOF 5.00 5.00 4 4 38 68.48 62.60 15.47% 2.62 2.62 2.00 117 62.60 60.58 1.73% Gutter 0.02 3.61 19.18 0.19 4.29 0.45 5.00 5.00 6 6 49 62.04 58.09 8.06% 5.88 5.88 5.55 208 58.09 56.99 0.53% Swale (8:1) 0.04 8.00 16.12 0.50 1.94 1.79 7.66 7.34 5 5 42 68.68 67.08 3.82% 4.45 4.45 3.44 24 67.08 66.23 3.49% Gutter 0.02 3.61 19.18 0.19 6.09 0.07 5.00 5.00 Tc2 Tc10 Tc100 C2 C10 C100 I2 I10 I100 Q2 Q10 Q100 Historic Basins: imp. areas lot 2 & 3 Imp. Areas lot 2 & 3 0.70 5.7 5.7 5.0 1.0 1.0 1.0 2.8 4.7 10.0 1.8 3.1 7.0 perv. areas lot 2 & 3 Perv. Areas lot 2 & 3 0.46 12.5 12.5 12.5 0.4 0.4 0.5 2.1 3.5 7.2 0.4 0.7 1.7 imp. areas lot 4 Imp. Areas lot 4 0.62 5.0 5.0 5.0 0.9 0.9 1.0 2.9 4.9 10.0 1.7 2.8 6.1 perv. areas lot 4 Perv. Areas lot 4 3.20 11.6 11.6 9.6 0.5 0.5 0.6 2.1 3.6 7.9 3.3 5.6 15.4 Developed Basins: 1a 1a 0.05 5.0 5.0 5.0 1.0 1.0 1.0 2.9 4.9 10.0 0.1 0.2 0.5 1b 1b 0.08 5.0 5.0 5.0 1.0 1.0 1.0 2.9 4.9 10.0 0.2 0.4 0.8 1c 1c 0.48 5.0 5.0 5.0 1.0 1.0 1.0 2.9 4.9 10.0 1.3 2.2 4.8 1d 1d 1.80 11.7 11.7 11.0 0.6 0.6 0.7 2.1 3.6 7.6 2.2 3.7 9.7 2 2 0.61 5.6 5.6 5.0 0.8 0.8 1.0 2.8 4.7 10.0 1.4 2.4 6.1 3a 3a 0.01 5.0 5.0 5.0 1.0 1.0 1.0 2.9 4.9 10.0 0.0 0.0 0.1 3b 3b 0.39 5.0 5.0 5.0 0.9 0.9 1.0 2.9 4.9 10.0 1.0 1.7 3.9 3c 3c 0.05 5.0 5.0 5.0 0.9 0.9 1.0 2.9 4.9 10.0 0.1 0.2 0.5 4 4 0.29 5.0 5.0 5.0 0.5 0.5 0.7 2.9 4.9 10.0 0.4 0.8 1.9 6 6 0.36 7.7 7.7 7.3 0.2 0.2 0.3 2.5 4.2 8.8 0.2 0.3 0.8 5 5 0.16 5.0 5.0 5.0 0.5 0.5 0.7 2.9 4.9 10.0 0.2 0.4 1.1 7 7 0.11 5.0 5.0 5.0 0.6 0.6 0.7 2.9 4.9 10.0 0.2 0.3 0.8 8 8 0.12 5.0 5.0 5.0 0.4 0.4 0.6 2.9 4.9 10.0 0.15 0.26 0.67 9 9 0.14 7.2 7.2 6.8 0.2 0.2 0.3 2.5 4.3 9.1 0.07 0.12 0.31 10 10 0.03 5.0 5.0 5.0 0.2 0.2 0.3 2.9 4.9 10.0 0.02 0.03 0.07 11 11 0.05 5.0 5.0 5.0 0.2 0.2 0.3 2.9 4.9 10.0 0.03 0.05 0.13 12 12 0.14 5.0 5.0 5.0 0.6 0.6 0.7 2.9 4.9 10.0 0.23 0.40 1.01 co1 Co1 0.43 5.0 5.0 5.0 0.7 0.7 0.9 2.9 4.9 10.0 0.91 1.56 3.98 w8 W8 1.5 3.0 6.9 w10 W10 2.8 5.6 13.2 w11 W11 1.8 3.5 8.1 1a, 1b, 1c, 1d (North Rain Garden) 2.41 11.5 11.5 9.8 0.7 0.7 0.8 2.1 3.6 7.9 3.43 5.84 15.84 3a, 3b, 3c (South Rain Garden) 0.45 5.0 5.0 5.0 0.9 0.9 1.0 2.9 4.9 10.0 1.14 1.96 4.47 2, 4, 6 to Extended Detention Basin WQ 1.26 5.1 5.1 5.0 0.6 0.6 0.7 2.9 4.9 10.0 2.12 3.62 9.25 and 6 to Detention Pond 4.12 11.5 11.5 9.8 0.7 0.7 0.8 2.1 3.6 7.9 5.87 10.00 27.11 DEVELOPED DIRECT RUNOFF COMPUTATIONS Intensity (in/hr) Flow (cfs) Powerhouse 2 C. Ortiz December 13, 2022 Design NORTHERNENGINEERING.COM | 970.221.4158 FINAL DRAINAGE REPORT: POWERHOUSE 2 FORT COLLINS | GREELEY APPENDIX APPENDIX B DETENTION POND COMPUTATION COG Pond No : 1 6 100-yr 0.84 WQCV 1160 ft 3 Area (A)= 4.12 acres Detention 9958 ft 3 Max Release Rate = 11.50 cfs Total 0.26 ac-ft Time Time 100-yr Intensity Q100 Inflow (Runoff) Volume Outflow (Release) Volume Storage Detention Volume (mins) (secs) (in/hr) (cfs) (ft 3 ) (ft 3 ) (ft 3 ) 5 300 9.950 34.43 10330 3450.0 6880.5 10 600 7.720 26.72 16030 6900.0 9130.4 15 900 6.520 22.56 20308 10350.0 9958.0 20 1200 5.600 19.38 23257 13800.0 9456.6 25 1500 4.980 17.23 25852 17250.0 8602.2 30 1800 4.520 15.64 28157 20700.0 7457.1 35 2100 4.080 14.12 29652 24150.0 5502.1 40 2400 3.740 12.94 31064 27600.0 3464.1 45 2700 3.460 11.97 32331 31050.0 1280.8 50 3000 3.230 11.18 33535 34500.0 -964.8 55 3300 3.030 10.49 34605 37950.0 -3345.5 60 3600 2.860 9.90 35632 41400.0 -5767.6 65 3900 2.720 9.41 36712 44850.0 -8137.8 70 4200 2.590 8.96 37647 48300.0 -10653.4 75 4500 2.480 8.58 38623 51750.0 -13127.5 80 4800 2.380 8.24 39536 55200.0 -15663.8 85 5100 2.290 7.93 40419 58650.0 -18231.3 90 5400 2.210 7.65 41301 62100.0 -20798.8 95 5700 2.130 7.37 42018 65550.0 -23532.4 100 6000 2.060 7.13 42775 69000.0 -26224.5 105 6300 2.000 6.92 43606 72450.0 -28843.9 110 6600 1.940 6.71 44312 75900.0 -31587.9 115 6900 1.890 6.54 45132 79350.0 -34217.7 120 7200 1.840 6.37 45849 82800.0 -36951.3 Developed "C" = Calculations By: Input Variables Results Design Point Design Storm Required Detention Volume DETENTION POND CALCULATION; FAA METHOD Project Number : 207-030 Project Title Date: Project Number Calcs By: City Basins 1 WQCV = Watershed inches of Runoff (inches) 61% a = Runoff Volume Reduction (constant) i = Total imperviousness Ratio (i = Iwq/100) 0.240 in A = 4.12 ac V = 0.10 ac-ft V = 1.2 x Water Quality Design Volume (ac-ft) WQCV = Water Quality Capture Volume (inches) A = Watershed Area (acres) Provided (LID) Rain Gardens = Volume to be provided in the Pond = 0.03 Ac-ft dia (in) = 13/16 number of columns= 1.00 number of rows = 2.00 number of holes = 2.00 Area Per Row = 0.52 square inches Total Outlet Area (in2) = 1.04 <-- CALCULATED from total number of holes Circular Perforation Sizing 3139 cu. ft. 1160 cu. ft. Powerhouse II December 14, 2022 207-030 C. Ortiz Fort Collins 4299 cu. ft. Drain Time a = i = WQCV = Figure EDB-2 - Water Quality Capture Volume (WQCV), 80th Percentile Runoff Event 1, 2, 3, 4, and 6 DETENTION POND Dp1 0.231 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 WQCV (watershed inches) Total Imperviousness Ratio (i = Iwq Project: Date: 12/13/2022 WQCV ELEVATION : (A) (B) (C) (D) Total Volume Detention = 1,159.99 0.03 Ac. Elevation Depth Area Volume Σ Volume Σ Volume Elev. (A1) = 4,958.50 (Sf.) (Cf.) (Cf.) (Ac.-ft.) Σ Volume (D1) = 239.44 Partial volume (C2) = 1,178.87 Outlet Elevation: 4,958.11 1.00 Depth, partial volume = 0.50 0.39 239.44 239.44 0.01 >>>>>>>>> 4,958.50 1,226.92 High water level (HWL) = 4958.89 0.50 1,178.87 1,418.31 0.03 4,959.00 3,488.55 Water Depth = 0.78 Ft. 0.50 2,370.19 3,788.50 0.09 4,959.50 5,992.21 0.50 3,796.67 7,585.17 0.17 4,960.00 9,194.48 0.50 4,904.95 12,490.12 0.29 4,960.50 10,425.31 ACTUAL STORAGE : (A) (B) (C) (D) Total Volume Detention = 11,117.73 0.26 Ac. Elevation Depth Area Volume Σ Volume Σ Volume Elev. (A1) = 4,960.00 (Sf.) (Cf.) (Cf.) (Ac.-ft.) Σ Volume (D1) = 7,585.17 Partial volume (C2) = 4,904.95 Outlet Elevation: 4,958.11 1.00 Depth, partial volume = 0.50 0.39 239.44 239.44 0.01 4,958.50 1,226.92 High water level (HWL) = 4960.36 0.50 1,178.87 1,418.31 0.03 Free board = 0.14 4,959.00 3,488.55 Top pond bank elevation = 4960.50 0.50 2,370.19 3,788.50 0.09 4,959.50 5,992.21 Water Depth = 2.25 Ft. Detention Req'd 0.50 3,796.67 7,585.17 0.17 >>>>>>>>> 4,960.00 9,194.48 0.50 4,904.95 12,490.12 0.29 4,960.50 10,425.31 Pond No.: 1 Detention Pond Stage Storage Curve Pond Stage Storage Curve Project Number: 207-030 Project Location: Fort Collins, Colorado Calculations By: C. Ortiz Powerhouse II 207-030 - D-pond_Capacity, Det. Pond-1, 12/13/2022, 10:04 AM Stormwater Facility Name: Facility Location & Jurisdiction: User (Input) Watershed Characteristics User Defined User Defined User Defined User Defined Watershed Slope = 0.005 ft/ft Stage [ft] Area [ft^2] Stage [ft] Discharge [cfs] Watershed Length-to-Width Ratio = 2.72 L:W 0.00 26 0.00 0.00 Watershed Area = 4.12 acres 0.50 1,227 0.50 5.35 Watershed Imperviousness = 61.0% percent 1.00 3,489 1.00 6.35 Percentage Hydrologic Soil Group A = 0.0% percent 1.50 5,992 1.50 7.22 Percentage Hydrologic Soil Group B = 0.0% percent 2.00 9,194 2.00 7.99 Percentage Hydrologic Soil Groups C/D = 100.0% percent 2.50 10,425 2.50 8.69 2.69 12,896 2.69 9.09 User Input: Detention Basin Characteristics WQCV Design Drain Time = 40.00 hours After completing and printing this worksheet to a pdf, go to: https://maperture.digitaldataservices.com/gvh/?viewer=cswdif, create a new stormwater facility, and attach the pdf of this worksheet to that record. Routed Hydrograph Results Design Storm Return Period = WQCV 2 Year 5 Year 10 Year 25 Year 50 Year 100 Year Two-Hour Rainfall Depth = 0.53 0.98 1.36 1.71 2.31 2.91 3.67 in Calculated Runoff Volume = 0.081 0.197 0.318 0.431 0.640 0.837 1.107 acre-ft OPTIONAL Override Runoff Volume = acre-ft Inflow Hydrograph Volume = 0.081 0.197 0.317 0.431 0.640 0.836 1.106 acre-ft Time to Drain 97% of Inflow Volume = 1 1 1 1 1 2 2 hours Time to Drain 99% of Inflow Volume = 1 1 1 1 1 2 2 hours Maximum Ponding Depth = 0.13 0.32 0.53 0.91 1.56 2.03 2.63 ft Maximum Ponded Area = 0.008 0.018 0.031 0.071 0.145 0.213 0.276 acres Maximum Volume Stored = 0.001 0.003 0.008 0.027 0.096 0.183 0.320 acre-ft Stormwater Detention and Infiltration Design Data Sheet Powerhouse II Fort Collins, Colorado Workbook Protected Worksheet Protected 6573312, Design Data 12/13/2022, 3:33 PM Doing_Clear_Formatting Yes = CountA= 1 0 1 2 3 #N/A #N/A 0 1 2 3 #N/A #N/A Check Data Set 1 Check Data Set 1 Stormwater Detention and Infiltration Design Data Sheet Area Discharge 0 2 4 6 8 10 12 14 16 18 20 0.1 1 10 FLOW [cfs] TIME [hr] 100YR IN 100YR OUT 50YR IN 50YR OUT 25YR IN 25YR OUT 10YR IN 10YR OUT 5YR IN 5YR OUT 2YR IN 2YR OUT WQCV IN WQCV OUT 0 0.5 1 1.5 2 2.5 3 0.1 1 10 100 PONDING DEPTH [ft] DRAIN TIME [hr] 100YR 50YR 25YR 10YR 5YR 2YR WQCV 6573312, Design Data 12/13/2022, 3:33 PM NORTHERNENGINEERING.COM | 970.221.4158 FINAL DRAINAGE REPORT: POWERHOUSE 2 FORT COLLINS | GREELEY APPENDIX APPENDIX C HYDRAULIC COMPUTATIONS C.1 – STORM SEWERS C.2 – INLETS WIERS & SWALES C.3 - SCOURSTOP AND EROSION NORTHERNENGINEERING.COM | 970.221.4158 FINAL DRAINAGE REPORT: POWERHOUSE 2 FORT COLLINS | GREELEY APPENDIX APPENDIX C HYDRAULIC COMPUTATIONS C.1 – STORM SEWERS NORTHERNENGINEERING.COM | 970.221.4158 FINAL DRAINAGE REPORT: POWERHOUSE 2 FORT COLLINS | GREELEY APPENDIX APPENDIX C HYDRAULIC COMPUTATIONS C.2 – INLETS WIERS & SWALES Area Inlet Performance Curve: PowerHouse 2 - Design Point w10/Inlet OA2 Governing Equations: At low flow depths, the inlet will act like a weir governed by the following equation: * where P = 2(L + W) * where H corresponds to the depth of water above the flowline At higher flow depths, the inlet will act like an orifice governed by the following equation: * where A equals the open area of the inlet grate * where H corresponds to the depth of water above the centroid of the cross-sectional area (A) The exact depth at which the inlet ceases to act like a weir, and begins to act like an orifice is unknown. However, what is known, is that the stage-discharge curves of the weir equation and the orifice equation will cross at a certain flow depth. The two curves can be found below: If H > 1.792 (A/P), then the grate operates like an orifice; otherwise it operates like a weir. Input Parameters: Type of Grate: CDOT Type C Close Mesh Grate Double Shape Rectangular Length of Grate (ft): 2.48 Width of Grate (ft): 1.85 Open Area of Grate (ft 2 ): 2.68 Flowline Elevation (ft): 4959.500 Allowable Capacity: 50% Depth vs. Flow: Depth Above Inlet (ft) Elevation (ft) Shallow Weir Flow (cfs) Orifice Flow (cfs) Actual Flow (cfs) 0.00 4959.50 0.00 0.00 0.00 0.10 4959.60 0.41 2.28 0.41 0.20 4959.70 1.16 3.22 1.16 0.30 4959.80 2.13 3.94 2.13 Q100 0.40 4959.90 3.29 4.55 3.29 0.50 4960.000 4.59 5.09 4.59 0.60 4960.10 6.04 5.58 5.58 0.70 4960.20 7.61 6.03 6.03 0.80 4960.30 9.29 6.44 6.44 0.90 4960.40 11.09 6.83 6.83 1.00 4960.500 12.99 7.20 7.20 Inlet at Design Point OA2 full 2-yr flow of 2.80 cfs at the elevation 0.35 above the inlet elevation. 0.00 2.00 4.00 6.00 8.00 10.00 12.00 0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90 1.00 Discharge (cfs) Stage (ft) Stage - Discharge Curves Weir Flow Area Inlet Performance Curve: PowerHouse 2 - Outlet B Governing Equations: At low flow depths, the inlet will act like a weir governed by the following equation: * where P = 2(L + W) * where H corresponds to the depth of water above the flowline At higher flow depths, the inlet will act like an orifice governed by the following equation: * where A equals the open area of the inlet grate * where H corresponds to the depth of water above the centroid of the cross-sectional area (A) The exact depth at which the inlet ceases to act like a weir, and begins to act like an orifice is unknown. However, what is known, is that the stage-discharge curves of the weir equation and the orifice equation will cross at a certain flow depth. The two curves can be found below: If H > 1.792 (A/P), then the grate operates like an orifice; otherwise it operates like a weir. Input Parameters: Type of Grate: Standar Inlet grate for Type C Shape Rectangular Length of Grate (ft): 3.38 Width of Grate (ft): 2.22 Open Area of Grate (ft 2 ): 8.51 Flowline Elevation (ft): 4960.360 Allowable Capacity: 50% Depth vs. Flow: Depth Above Inlet (ft) Elevation (ft) Shallow Weir Flow (cfs) Orifice Flow (cfs) Actual Flow (cfs) 0.00 4960.36 0.00 0.00 0.00 0.10 4960.46 0.53 7.23 0.53 0.20 4960.56 1.50 10.23 1.50 0.30 4960.66 2.76 12.52 2.76 Q100 0.40 4960.76 4.25 14.46 4.25 0.50 4960.860 5.94 16.17 5.94 0.60 4960.96 7.81 17.71 7.81 0.70 4961.06 9.84 19.13 9.84 0.80 4961.16 12.02 20.45 12.02 0.90 4961.26 14.34 21.69 14.34 1.00 4961.360 16.80 22.87 16.80 Inlet at Outlet B flow of 3.0 cfs at the elevation 0.32 above the inlet elevation. 0.00 5.00 10.00 15.00 20.00 25.00 0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90 1.00 Discharge (cfs) Stage (ft) Stage - Discharge Curves Weir Flow Orifice Flow 3130 Verona Avenue • Buford, GA 30518 (866) 888-8479 / (770) 932-2443 • Fax: (770) 932-2490 © Nyloplast Inlet Capacity Charts June 2012 0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 4.00 0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 0.45 0.50 0.55 0.60 0.65 0.70 0.75 0.80 0.85 0.90 0.95 1.00 1.05 1.10 Capacity (cfs) Head (ft) Nyloplast 15" Standard Grate Inlet Capacity Chart Area Inlet Performance Curve: PowerHouse 2 - Design Rain Garden R3 Governing Equations: At low flow depths, the inlet will act like a weir governed by the following equation: * where P = 2(L + W) * where H corresponds to the depth of water above the flowline At higher flow depths, the inlet will act like an orifice governed by the following equation: * where A equals the open area of the inlet grate * where H corresponds to the depth of water above the centroid of the cross-sectional area (A) The exact depth at which the inlet ceases to act like a weir, and begins to act like an orifice is unknown. However, what is known, is that the stage-discharge curves of the weir equation and the orifice equation will cross at a certain flow depth. The two curves can be found below: If H > 1.792 (A/P), then the grate operates like an orifice; otherwise it operates like a weir. Input Parameters: Type of Grate: CDOT Type C Close Mesh Grate Double Shape Rectangular Length of Grate (ft): 3.71 Width of Grate (ft): 2.48 Open Area of Grate (ft 2 ): 5.36 Flowline Elevation (ft): 4964.090 Allowable Capacity: 50% Depth vs. Flow: Depth Above Inlet (ft) Elevation (ft) Shallow Weir Flow (cfs) Orifice Flow (cfs) Actual Flow (cfs) 0.00 4964.09 0.00 0.00 0.00 0.10 4964.19 0.59 4.55 0.59 0.20 4964.29 1.66 6.44 1.66 Q100 0.30 4964.39 3.05 7.89 3.05 0.40 4964.49 4.70 9.11 4.70 0.50 4964.590 6.57 10.18 6.57 0.60 4964.69 8.63 11.16 8.63 0.70 4964.79 10.88 12.05 10.88 0.80 4964.89 13.29 12.88 12.88 0.90 4964.99 15.86 13.66 13.66 1.00 4965.090 18.57 14.40 14.40 Inlet at Design Rain Garden R3 flow of 1.76 cfs at the elevation 0.23 above the inlet elevation. 0.00 2.00 4.00 6.00 8.00 10.00 12.00 14.00 16.00 18.00 0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90 1.00 Discharge (cfs) Area Inlet Performance Curve: PowerHouse 2 - Design North Rain Garden Governing Equations: At low flow depths, the inlet will act like a weir governed by the following equation: * where P = 2(L + W) * where H corresponds to the depth of water above the flowline At higher flow depths, the inlet will act like an orifice governed by the following equation: * where A equals the open area of the inlet grate * where H corresponds to the depth of water above the centroid of the cross-sectional area (A) The exact depth at which the inlet ceases to act like a weir, and begins to act like an orifice is unknown. However, what is known, is that the stage-discharge curves of the weir equation and the orifice equation will cross at a certain flow depth. The two curves can be found below: If H > 1.792 (A/P), then the grate operates like an orifice; otherwise it operates like a weir. Input Parameters: Type of Grate: CDOT Type C Close Mesh Grate Double Shape Rectangular Length of Grate (ft): 6.75 Width of Grate (ft): 2.22 Open Area of Grate (ft 2 ): 17.01 Flowline Elevation (ft): 4961.000 Allowable Capacity: 50% Depth vs. Flow: (Too much Depth, Inlet will be at a 4:1 Slope) Depth Above Inlet (ft) Elevation (ft) Shallow Weir Flow (cfs) Orifice Flow (cfs) Actual Flow (cfs) 0.00 4961.00 0.00 0.00 0.00 0.10 4961.10 0.85 14.45 0.85 0.20 4961.20 2.41 20.44 2.41 0.30 4961.30 4.42 25.04 4.42 0.40 4961.40 6.81 28.91 6.81 0.50 4961.500 9.51 32.32 9.51 0.60 4961.60 12.51 35.41 12.51 0.70 4961.70 15.76 38.24 15.76 Q100 0.80 4961.80 19.26 40.88 19.26 0.90 4961.90 22.98 43.36 22.98 1.00 4962.000 26.91 45.71 26.91 Inlet at Design North Rain Garden flow of 15.70 cfs at the elevation 0.7 above the inlet elevation. 0.00 5.00 10.00 15.00 20.00 25.00 30.00 35.00 40.00 45.00 50.00 0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90 1.00 Design Information (Input) MINOR MAJOR Type of Inlet Type = Local Depression (additional to continuous gutter depression 'a' from above) alocal = 2.00 2.00 inches Number of Unit Inlets (Grate or Curb Opening) No = 1 1 Water Depth at Flowline (outside of local depression) Ponding Depth = 5.6 6.3 inches Grate Information MINOR MAJOR Length of a Unit Grate Lo (G) = 3.00 3.00 feet Width of a Unit Grate Wo = 1.73 1.73 feet Area Opening Ratio for a Grate (typical values 0.15-0.90) Aratio = 0.43 0.43 Clogging Factor for a Single Grate (typical value 0.50 - 0.70) Cf (G) = 0.50 0.50 Grate Weir Coefficient (typical value 2.15 - 3.60) Cw (G) = 3.30 3.30 Grate Orifice Coefficient (typical value 0.60 - 0.80) Co (G) = 0.60 0.60 Curb Opening Information MINOR MAJOR Length of a Unit Curb Opening Lo (C) = 3.00 3.00 feet Height of Vertical Curb Opening in Inches Hvert = 6.50 6.50 inches Height of Curb Orifice Throat in Inches Hthroat = 5.25 5.25 inches Angle of Throat (see USDCM Figure ST-5) Theta = 0.00 0.00 degrees Side Width for Depression Pan (typically the gutter width of 2 feet) Wp = 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) = 3.70 3.70 Curb Opening Orifice Coefficient (typical value 0.60 - 0.70) Co (C) = 0.66 0.66 Low Head Performance Reduction (Calculated) MINOR MAJOR Depth for Grate Midwidth dGrate = 0.489 0.549 ft Depth for Curb Opening Weir Equation dCurb = 0.30 0.36 ft Combination Inlet Performance Reduction Factor for Long Inlets RFCombination = 0.87 0.99 Curb Opening Performance Reduction Factor for Long Inlets RFCurb = 1.00 1.00 Grated Inlet Performance Reduction Factor for Long Inlets RFGrate = 0.87 0.99 MINOR MAJOR Total Inlet Interception Capacity (assumes clogged condition) Qa = 3.0 4.1 cfs WARNING: Inlet Capacity less than Q Peak for Major Storm Q PEAK REQUIRED = 1.4 6.7 cfs CDOT/Denver 13 Combination INLET IN A SUMP OR SAG LOCATION MHFD-Inlet, Version 5.01 (April 2021) H-Vert H-Curb W Lo (C) Lo (G) Wo Project: Inlet ID: Gutter Geometry: Maximum Allowable Width for Spread Behind Curb TBACK = 1.0 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 = 0.015 Height of Curb at Gutter Flow Line HCURB = 6.00 inches Distance from Curb Face to Street Crown TCROWN = 24.0 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 = 0.015 Minor Storm Major Storm Max. Allowable Spread for Minor & Major Storm TMAX = 17.0 20.0 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 based on Depth Criterion Minor Storm Major Storm MAJOR STORM Allowable Capacity is based on Depth Criterion Qallow = SUMP SUMP cfs MHFD-Inlet, Version 5.01 (April 2021) ALLOWABLE CAPACITY FOR ONE-HALF OF STREET (Minor & Major Storm) (Based on Regulated Criteria for Maximum Allowable Flow Depth and Spread) Inlet DP2 1 Weir Report Hydraflow Express Extension for Autodesk® Civil 3D® by Autodesk, Inc. Tuesday, Dec 13 2022 CURB CUT Rectangular Weir Crest = Sharp Bottom Length (ft) = 4.00 Total Depth (ft) = 0.50 Calculations Weir Coeff. Cw = 3.33 Compute by: Known Depth Known Depth (ft) = 0.25 Highlighted Depth (ft) = 0.25 Q (cfs) = 1.665 Area (sqft) = 1.00 Velocity (ft/s) = 1.67 Top Width (ft) = 4.00 0 .5 1 1.5 2 2.5 3 3.5 4 4.5 5 Depth (ft) CURB CUT Depth (ft) -0.50 -0.50 0.00 0.00 0.50 0.50 1.00 1.00 Length (ft) Weir W.S. Channel Report Hydraflow Express Extension for Autodesk® Civil 3D® by Autodesk, Inc. Tuesday, Dec 13 2022 Swale Section 1 -1 Triangular Side Slopes (z:1) = 15.00, 8.00 Total Depth (ft) = 1.40 Invert Elev (ft) = 1.00 Slope (%) = 1.25 N-Value = 0.035 Calculations Compute by: Known Q Known Q (cfs) = 10.90 Highlighted Depth (ft) = 0.66 Q (cfs) = 10.90 Area (sqft) = 5.01 Velocity (ft/s) = 2.18 Wetted Perim (ft) = 15.24 Crit Depth, Yc (ft) = 0.57 Top Width (ft) = 15.18 EGL (ft) = 0.73 0 5 10 15 20 25 30 35 40 45 Elev (ft) Depth (ft) Section 0.50 -0.50 1.00 0.00 1.50 0.50 2.00 1.00 2.50 1.50 3.00 2.00 Reach (ft) NORTHERNENGINEERING.COM | 970.221.4158 FINAL DRAINAGE REPORT: POWERHOUSE 2 FORT COLLINS | GREELEY APPENDIX APPENDIX C HYDRAULIC COMPUTATIONS C.3 - SCOURSTOP AND EROSION Storm Drain/ Design Point W (FT) L (FT) Quantity of Mats Velocity (ft/s) Storm Drain C ( 2 - 14"x23" HEP RCP) 4 4 1 6.93 Storm Drain D (14"x23" HEP RCP) 4 4 1 5.34 Storm Drain G (12" HDPE) 4 4 1 8.61 4' Curb Cut (DP 4 ) 4 4 1 1.67 Notes: 1. Refer to Scourstop design brochure for sizing requirments 2. DP = Design Point - Refer to Drainage Exhibit for clarification Scourstop Summary NORTHERNENGINEERING.COM | 970.221.4158 FINAL DRAINAGE REPORT: POWERHOUSE 2 FORT COLLINS | GREELEY APPENDIX APPENDIX D EROSION CONTROL REPORT NORTHERNENGINEERING.COM | 970.221.4158 FINAL DRAINAGE REPORT: POWERHOUSE 2 FORT COLLINS | GREELEY EROSION CONTROL REPORT EROSION CONTROL REPORT A comprehensive Erosion and Sediment Control Plan (along with associated details) will be included with the final construction drawings. It should be noted; however, any such Erosion and Sediment Control Plan serves only as a general guide to the Contractor. Staging and/or phasing of the BMPs depicted, and additional or different BMPs from those included may be necessary during construction, or as required by the authorities having jurisdiction. It shall be the responsibility of the Contractor to ensure erosion control measures are properly maintained and followed. The Erosion and Sediment Control Plan is intended to be a living document, constantly adapting to site conditions and needs. The Contractor shall update the location of BMPs as they are installed, removed, or modified in conjunction with construction activities. It is imperative to reflect the current site conditions appropriately always. The Erosion and Sediment Control Plan shall address both temporary measures to be implemented during construction, as well as permanent erosion control protection. Best Management Practices from the Volume 3, Chapter 7 – Construction BMPs will be utilized. Measures may include, but are not limited to, silt fencing and/or wattles along the disturbed perimeter, gutter protection in the adjacent roadways, and inlet protection at existing and proposed storm inlets. Vehicle tracking control pads, spill containment and clean-up procedures, designated concrete washout areas, dumpsters, and job site restrooms shall also be provided by the Contractor. Grading and Erosion Control Notes can be found on Sheet CS2 of the Utility Plans. The Final Utility Plans will also contain a full-size Erosion Control Plan as well as a separate sheet dedicated to Erosion Control Details. In addition to this report and the referenced plan sheets, the Contractor shall be aware of, and adhere to, the applicable requirements outlined in any existing Development Agreement(s) of record, as well as the Development Agreement, to be recorded prior to issuance of the Development Construction Permit. Also, the Site Contractor for this project may be required to secure a Stormwater Construction General Permit from the Colorado Department of Public Health and Environment (CDPHE), Water Quality Control Division – Stormwater Program, before commencing any earth disturbing activities. Prior to securing said permit, the Site Contractor shall develop a comprehensive Storm Water Management Plan (SWMP) pursuant to CDPHE requirements and guidelines. The SWMP will further describe and document the ongoing activities, inspections, and maintenance of construction BMPs. NNORTHERNENGINEERING.COM | 970.221.4158 FINAL DRAINAGE REPORT: POWERHOUSE 2 FORT COLLINS | GREELEY APPENDIX APPENDIX E LID DESIGN INFORMATION VAULT CABLE T VAULT F.O. F.O. CONTROL IRR CONTROL IRR GAS OHU OHU LID MH / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / GAS VAULT CABLE CONTROL IRR CONTROL IRR CONTROL IRR CONTROL IRR EAST VINE DRIVE NORTH COLLEGE AVENUE JEROME STREET UD UD UD UD UD UD UD UD SOUTH RAIN GARDENS REQUIRED VOLUME: 472 CU. FT. MINIMUM FLAT AREA: 333 SF PROVIDED VOLUME: 1,192 CU. FT. PROVIDED FLAT AREA: 1,431 SF TREATMENT AREA: 18,094.44 SF NORTH RAIN GARDEN REQUIRED VOLUME: 1,669 CU. FT. MINIMUM FLAT AREA: 1,272 SF PROVIDED VOLUME: 1,947 CU. FT. PROVIDED FLAT AREA: 2,970 SF TREATMENT AREA: 68,535.50 SF JEROME STREET LLC, 216 E OAK ST JEROME STREET STATION LLC, 742 N COLLEGE AVE LMC VENTURES LLC, Sheet 1 of 2 Designer: Company: Date: Project: Location: 1. Basin Storage Volume A) Effective Imperviousness of Tributary Area, Ia Ia = 60.0 % (100% if all paved and roofed areas upstream of rain garden) B) Tributary Area's Imperviousness Ratio (i = Ia/100) i = 0.600 C) Water Quality Capture Volume (WQCV) for a 12-hour Drain Time WQCV = 0.19 watershed inches (WQCV= 0.8 * (0.91* i3 - 1.19 * i2 + 0.78 * i) D) Contributing Watershed Area (including rain garden area) Area = 106,005 sq ft E) Water Quality Capture Volume (WQCV) Design Volume VWQCV = 1,669 cu ft Vol = (WQCV / 12) * Area F) For Watersheds Outside of the Denver Region, Depth of d6 = in Average Runoff Producing Storm G) For Watersheds Outside of the Denver Region, VWQCV OTHER = 1,998.0 cu ft Water Quality Capture Volume (WQCV) Design Volume H) User Input of Water Quality Capture Volume (WQCV) Design Volume VWQCV USER = cu ft (Only if a different WQCV Design Volume is desired) 2. Basin Geometry A) WQCV Depth (12-inch maximum) DWQCV = 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 = 1272 sq ft D) Actual Flat Surface Area AActual = 2970 sq ft E) Area at Design Depth (Top Surface Area) ATop = 4818 sq ft F) Rain Garden Total Volume VT= 1,947 cu ft (VT= ((ATop + AActual) / 2) * Depth) 3. Growing Media 4. Underdrain System A) Are underdrains provided? B) Underdrain system orifice diameter for 12 hour drain time i) Distance From Lowest Elevation of the Storage y = N/A ft Volume to the Center of the Orifice ii) Volume to Drain in 12 Hours Vol12 = N/A cu ft iii) Orifice Diameter, 3/8" Minimum DO = N/A in Design Procedure Form: Rain Garden (RG) C. Ortiz Northern Engineering December 13, 2022 Powerhouse II North Rain Garden (Basin 1a to 1d) UD-BMP (Version 3.06, November 2016) Choose One Choose One 18" Rain Garden Growing Media Other (Explain): YES NO 207-030_RG-North_UD-BMP_v3.06, RG 12/13/2022, 9:56 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) C. Ortiz Northern Engineering December 13, 2022 Powerhouse II North Rain Garden (Basin 1a to 1d) 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 207-030_RG-North_UD-BMP_v3.06, RG 12/13/2022, 9:56 AM Sheet 1 of 2 Designer: Company: Date: Project: Location: 1. Basin Storage Volume A) Effective Imperviousness of Tributary Area, Ia Ia = 85.0 % (100% if all paved and roofed areas upstream of rain garden) B) Tributary Area's Imperviousness Ratio (i = Ia/100) i = 0.850 C) Water Quality Capture Volume (WQCV) for a 12-hour Drain Time WQCV = 0.29 watershed inches (WQCV= 0.8 * (0.91* i3 - 1.19 * i2 + 0.78 * i) D) Contributing Watershed Area (including rain garden area) Area = 19,567 sq ft E) Water Quality Capture Volume (WQCV) Design Volume VWQCV = 472 cu ft Vol = (WQCV / 12) * Area F) For Watersheds Outside of the Denver Region, Depth of d6 = in Average Runoff Producing Storm G) For Watersheds Outside of the Denver Region, VWQCV OTHER = 884.0 cu ft Water Quality Capture Volume (WQCV) Design Volume H) User Input of Water Quality Capture Volume (WQCV) Design Volume VWQCV USER = cu ft (Only if a different WQCV Design Volume is desired) 2. Basin Geometry A) WQCV Depth (12-inch maximum) DWQCV = 10 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 = 333 sq ft D) Actual Flat Surface Area AActual = 1431 sq ft E) Area at Design Depth (Top Surface Area) ATop = 1431 sq ft F) Rain Garden Total Volume VT= 1,192 cu ft (VT= ((ATop + AActual) / 2) * Depth) 3. Growing Media 4. Underdrain System A) Are underdrains provided? B) Underdrain system orifice diameter for 12 hour drain time i) Distance From Lowest Elevation of the Storage y = N/A ft Volume to the Center of the Orifice ii) Volume to Drain in 12 Hours Vol12 = N/A cu ft iii) Orifice Diameter, 3/8" Minimum DO = N/A in Design Procedure Form: Rain Garden (RG) C. Ortiz Northern Engineering December 13, 2022 Powerhouse II South Rain Garden (Basin 3a to 3c) UD-BMP (Version 3.06, November 2016) Choose One Choose One 18" Rain Garden Growing Media Other (Explain): YES NO 207-030_RG-South_UD-BMP_v3.06, RG 12/13/2022, 12:27 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) C. Ortiz Northern Engineering December 13, 2022 Powerhouse II South Rain Garden (Basin 3a to 3c) 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 207-030_RG-South_UD-BMP_v3.06, RG 12/13/2022, 12:27 AM NORTHERNENGINEERING.COM | 970.221.4158 FINAL DRAINAGE REPORT: POWERHOUSE 2 FORT COLLINS | GREELEY APPENDIX APPENDIX F SUPPORT DOCUMENTS PREVIOUS STUDIES AND USDA SOILS REPORT 430 North College Avenue Fort Collins, CO 80524 www.energy.colostate.edu September 19, 2022 Marsha Hilmes-Robinson Floodplain Administrator City of Fort Collins Re: Powerhouse II - Hazardous Material Storage and Handling of Flammable Materials Dear Marsha, This letter states the quantities of hazardous materials to be used at the proposed Powerhouse II facility. The quantities listed below and the removal of hydrogen storage from the site, will remove the designation of a “Critical Facility’, as per defined by the City of Fort Collins, from the project. The following outlines the handling and storage processes of hydrogen for research procedures anticipated at the proposed Powerhouse II facility: • Hydrogen produced by hydrolysis or similar method will be disposed of as produced via venting outdoors (as per any code requirements), burned in outdoors in a non-visible flare, consumed by fuel cell or similar device. • Onsite storage of hydrogen will remain at or below quantities regulated by international fire safety code or “household levels” • Hydrogen fueled vehicles, such as automobiles, light and medium duty trucks, and transit buses will be tested onsite and adhere to all fire safety codes and DOT regulations regarding hydrogen fueled vehicles. • H2 storage tanks will remain at Powerhouse I until approval of the LOMR. Flammable Materials: • Acetylene 1 commercial cylinder at 300 or less std. cu. Ft. volume • Oxygen 1 commercial cylinder at 300 or less std. cu. Ft. volume Non-Reactive Gases: • Compressed Air 500 gal. tank • Compressed Nitrogen 2000 L. Cryogenic Tank, Liquid • Compressed Argon 2000 L. Cryogenic Tank, Liquid • Compressed Helium <20 - 300 std. cu ft, steel cylinders • Compressed Argon <20 - 300 std. cu ft, steel cylinders • Compressed CO2 <20 - 300 std. cu ft, steel cylinders All listed non-reactive gases listed above have been evaluated and are found to be completely non-flammable, non-toxic, and inert gases. The only hazards posed by compressed nitrogen, argon, and CO2 are that they can be a simple asphyxiant if they displace enough air in a confined space and the mechanical energy stored by compression as with any compressed gas. The only hazards posed by the liquid nitrogen and argon is frostbite by direct contact and also a simple asphyxiant as they gasify in a confined space displacing the air. Please reach out with any questions or concerns. Best regards, Bryan Willson, Executive Director CSU Energy Institute DRAINAGE, WATER QUALITY AND EROSION CONTROL REPORT FOR THE POUDRE RIVER WHITEWATER PARK PROJECT PREPARED FOR: City of Fort Collins Park Planning & Development 215 North Mason Street Fort Collins, CO 80524 PREPARED BY: Anderson Consulting Engineers, Inc. 375 East Horsetooth Road, Building 5 Fort Collins, CO 80525 (ACE Project No. COFC18.1) June 6, 2017 COFC18.1 Drainage Report (June 6 2017).docx 3 Anderson Consulting Engineers, Inc. Figure 2.1 Site Map for the Poudre River Whitewater Project. Ca c he La Po u dre R iver Vine Dr Linden Street Cherry St College Ave Project Area Union Pacific Railroad Burlington Northern Railroad Jerome St 0 250 500 1,000 Feet COFC18.1 Drainage Report (June 6 2017).docx 14 Anderson Consulting Engineers, Inc. • Poudre River Pedestrian Bridge: As part of the City’s masterplan for the Poudre River Trail system, the trail will eventually be relocated to the northern side of the river between Linden Street and the BNSF Railroad when improvements to the Linde Street Bridge are implemented. In order to reconnect Poudre River trail users with the current trail as it passes underneath College Avenue, and to provide a pedestrian connection across the river for residents and businesses in northern Fort Collins, a new pedestrian bridge will be installed across the Poudre River as part of the project. The bridge will be 185-feet long and 15-feet wide. As identified on the Floodplain Plan provided as part of the Utility Plan drawings, the low chord elevation of the bridge (4964.0 NAVD88) will be located approximately 0.5-feet above the proposed/post-project base flood elevation of 4963.5. The bridge will also span the proposed/post-project floodway limits and a minimum 8-foot clearance will be provided between the low chord and proposed trails beneath the bridge. Since the bridge will be located above the base flood elevation, it will be designed as a non-breakaway bridge and will be incorporated into the hydraulic modeling conducted for the CLOMR/LOMR as part of this project. 5.2 Fully Developed Project Conditions Based on coordination with City stormwater staff, it was decided that a fully developed condition scenario would be developed to evaluate the sizing of proposed project infrastructure to accommodate fully developed conditions, as well as generate a conceptual drainage plan for future improvements. A figure depicting the fully developed project condition conveyance elements is provided as Sheet 2 in Appendix C. Tabular results from the fully developed project condition EPA SWMM model are also provided in Appendix C. Electronic copies of the fully developed project conditions EPA SWMM models are provided as digital data on the disk included with this report. A description of the fully developed proposed project condition is provided below: • Fully Developed Basins and Conceptual Detention Ponds: Subbasins 9, 11, 13, and 14 were assumed to be fully developed with increased impervious areas. Per the direction of City Stormwater staff, conceptual detention ponds were assumed for the three privately owned properties located north of Vine Drive (Subbasins 9, 11, and 14) to detain and release fully developed 100-year flows to a 2-year historic rate. It is noted that the conceptual detention ponds were simulated with a two-point rating curve. Conceptual detention for Subbasin 13 was not assumed per the development agreement between the City and the developer for this property. Fully developed flows from this basin will be conveyed underneath Vine Drive and into the water quality pond via the existing storm sewer system that was installed as part of the Innosphere development (Subbasin 12). COFC18.1 Drainage Report (June 6 2017).docx 15 Anderson Consulting Engineers, Inc. • Conceptual Future Vine Drive Improvements: In order to meet stormwater criteria, a 5-foot Type R inlet was conceptually assumed in the sump area on the north side of Vine Drive. Flow collected by this inlet, along with the detained released from Subbasins 9 and 11 is conceptually conveyed underneath Vine Drive in an 18-inch pipe. This pipe conceptually connects to the inlet on the south side of the street and into the storm drainage system proposed by the project. The installation of the inlet on the north side of the street will reduce the frequency of road overtopping for events less than the 50-year. Basin Name Area (ac) Width (ft)* OFL (ft) % Slope % Impervious (Proposed Conditions) % Impervious (Fully Developed) Description for Fully Developed Condition B-1 2.78 1211 100 2.00 60 60 Assumes 100% impervious for ponded area B-2 3.34 1455 100 3.00 50 50 Assumes 100% impervious for ponded area B-3 0.56 76 320 1.20 90 90 B-4 0.35 152 100 0.50 90 90 B-5 0.80 290 120 2.00 75 75 B-6 0.33 287 50 2.00 75 75 B-7 1.38 194 310 1.00 50 50 Assumes 100% impervious for ponded area B-8 0.74 101 320 1.20 90 90 B-9 4.68 371 550 1.00 45 85 Assumes property is fully developed B-10 1.50 163 400 0.90 90 90 B-11 0.89 194 200 0.50 45 85 Assumes property is fully developed B-12 2.50 573 190 4.40 85 85 B-13 2.77 710 170 1.00 25 85 Assumes property is fully developed B-14 2.51 497 220 0.50 25 85 Assumes property is fully developed *Width is calculated from area and Overland Flow Length (OFL) SWMM MODEL INPUT PARAMETERS Basin Name Area (ac) 2-Year Peak Runoff (cfs) 10-Year Peak Runoff (cfs) 100-Year Peak Runoff (cfs) 100-Year Peak Unit Runoff Rate (cfs/acre) B-1 2.78 4.8 10.5 25.6 9.2 B-2 3.34 4.8 11.1 29.3 8.8 B-3 0.56 1.2 2.3 5.2 9.3 B-4 0.35 0.8 1.6 3.4 9.8 B-5 0.80 1.7 3.4 7.7 9.6 B-6 0.33 0.7 1.5 3.3 9.8 B-7 1.38 1.8 3.6 9.2 6.6 B-8 0.74 1.5 3.0 6.9 9.3 B-9 4.68 7.5 15.7 38.3 8.2 B-10 1.50 2.8 5.6 13.2 8.8 B-11 0.89 1.8 3.5 8.1 9.1 B-12 2.50 5.9 11.5 24.6 9.9 B-13 2.77 6.2 11.9 26.6 9.6 B-14 2.51 4.9 9.8 22.7 9.0 FULLY DEVELOPED CONDITION BASIN RUNOFF RESULTS SWMM Element 2-Year Peak Discharge (cfs) 10-Year Peak Runoff (cfs) 100-Year Peak Runoff (cfs) Description D-6 1.8 3.5 8.1 P-17 0.8 0.9 1.1 N-7 0.8 0.9 1.1 P-16 0.8 0.9 1.1 D-5 7.5 15.7 38.3 P-15 3.1 3.9 5.0 N-6 1.5 3.0 7.3 S-3 0.0 0.0 4.2 N-14 2.8 5.6 16.6 S-4 0.0 0.0 7.3 P-14 2.8 5.6 6.7 N-13 5.3 7.0 9.4 P-13 5.3 7.0 9.4 P-7 1.5 3.0 3.0 N-5 2.7 5.3 7.0 P-6 2.7 5.1 5.7 S-2 0.0 0.0 1.0 N-4 6.0 8.6 12.6 P-5 6.0 8.6 10.2 N-3 8.7 13.7 22.5 S-1 7.7 12.3 20.1 N-2 7.7 12.3 20.1 P-4 7.5 11.6 18.5 D-1 10.7 20.8 40.1 P-3 6.8 12.3 23.2 D-4 4.9 9.8 22.7 P-12 1.2 1.4 1.8 N-12 1.2 1.4 1.8 P-11 1.2 1.4 1.8 N-11 1.7 1.7 1.9 P-10 1.3 2.1 2.1 N-10 6.2 11.9 26.6 S-6 5.5 11.4 26.0 N-9 12.0 23.7 50.9 P-9 12.0 20.1 50.9 N-8 12.0 20.1 50.9 P-8 11.8 20.1 50.9 D-3 14.2 24.4 63.3 S-5 2.8 12.9 44.0 D-2 6.5 19.4 76.0 P-2 4.1 8.1 11.4 N-1 9.6 19.3 32.4 P-1 9.6 19.3 32.4 O-1 9.6 19.3 32.4 FULLY DEVELOPED CONDITION DISCHARGE RESULTS Eastern Flow Path Western Flow Path Out- fall COLLEGE AVENUE CACHE LA POUDRE RIVER BNSF RAILROAD UNION PACIFIC RAILROAD JEROME STREET LINDEN STREET REDWOOD STREET VINE DRIVE COY DITCH COY DITCH LAKE CANAL LAKE CANAL Anderson Consulting Engineers, Inc Civil ▪ Water Resources ▪ Environmental 375 East Horsetooth Road, Building 5, Fort Collins, CO 80525 Phone (970) 226-0120 / Fax (970) 226-0121 www.acewater.com CITY OF FORT COLLINS POUDRE RIVER WHITEWATER PARK FULLY DEVELOPED CONDITION SUBBASIN AND CONVEYANCE ELEMENTS MAP 2 United States Department of Agriculture A product of the National Cooperative Soil Survey, a joint effort of the United States Department of Agriculture and other Federal agencies, State agencies including the Agricultural Experiment Stations, and local participants Custom Soil Resource Report for Larimer County Area, Colorado 207-030 Powerhouse II Natural Resources Conservation Service January 13, 2022 Preface Soil surveys contain information that affects land use planning in survey areas. They highlight soil limitations that affect various land uses and provide information about the properties of the soils in the survey areas. Soil surveys are designed for many different users, including farmers, ranchers, foresters, agronomists, urban planners, community officials, engineers, developers, builders, and home buyers. Also, conservationists, teachers, students, and specialists in recreation, waste disposal, and pollution control can use the surveys to help them understand, protect, or enhance the environment. Various land use regulations of Federal, State, and local governments may impose special restrictions on land use or land treatment. Soil surveys identify soil properties that are used in making various land use or land treatment decisions. The information is intended to help the land users identify and reduce the effects of soil limitations on various land uses. The landowner or user is responsible for identifying and complying with existing laws and regulations. Although soil survey information can be used for general farm, local, and wider area planning, onsite investigation is needed to supplement this information in some cases. Examples include soil quality assessments (http://www.nrcs.usda.gov/wps/ portal/nrcs/main/soils/health/) and certain conservation and engineering applications. For more detailed information, contact your local USDA Service Center (https://offices.sc.egov.usda.gov/locator/app?agency=nrcs) or your NRCS State Soil Scientist (http://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/contactus/? cid=nrcs142p2_053951). Great differences in soil properties can occur within short distances. Some soils are seasonally wet or subject to flooding. Some are too unstable to be used as a foundation for buildings or roads. Clayey or wet soils are poorly suited to use as septic tank absorption fields. A high water table makes a soil poorly suited to basements or underground installations. The National Cooperative Soil Survey is a joint effort of the United States Department of Agriculture and other Federal agencies, State agencies including the Agricultural Experiment Stations, and local agencies. The Natural Resources Conservation Service (NRCS) has leadership for the Federal part of the National Cooperative Soil Survey. Information about soils is updated periodically. Updated information is available through the NRCS Web Soil Survey, the site for official soil survey information. The U.S. Department of Agriculture (USDA) prohibits discrimination in all its programs and activities on the basis of race, color, national origin, age, disability, and where applicable, sex, marital status, familial status, parental status, religion, sexual orientation, genetic information, political beliefs, reprisal, or because all or a part of an individual's income is derived from any public assistance program. (Not all prohibited bases apply to all programs.) Persons with disabilities who require 2 alternative means for communication of program information (Braille, large print, audiotape, etc.) should contact USDA's TARGET Center at (202) 720-2600 (voice and TDD). To file a complaint of discrimination, write to USDA, Director, Office of Civil Rights, 1400 Independence Avenue, S.W., Washington, D.C. 20250-9410 or call (800) 795-3272 (voice) or (202) 720-6382 (TDD). USDA is an equal opportunity provider and employer. 3 Contents Preface.................................................................................................................... 2 How Soil Surveys Are Made..................................................................................5 Soil Map.................................................................................................................. 8 Soil Map................................................................................................................9 Legend................................................................................................................10 Map Unit Legend................................................................................................ 11 Map Unit Descriptions.........................................................................................11 Larimer County Area, Colorado...................................................................... 13 73—Nunn clay loam, 0 to 1 percent slopes.................................................13 81—Paoli fine sandy loam, 0 to 1 percent slopes....................................... 14 105—Table Mountain loam, 0 to 1 percent slopes...................................... 15 Soil Information for All Uses...............................................................................17 Soil Properties and Qualities.............................................................................. 17 Soil Qualities and Features.............................................................................17 Hydrologic Soil Group................................................................................. 17 References............................................................................................................22 4 How Soil Surveys Are Made Soil surveys are made to provide information about the soils and miscellaneous areas in a specific area. They include a description of the soils and miscellaneous areas and their location on the landscape and tables that show soil properties and limitations affecting various uses. Soil scientists observed the steepness, length, and shape of the slopes; the general pattern of drainage; the kinds of crops and native plants; and the kinds of bedrock. They observed and described many soil profiles. A soil profile is the sequence of natural layers, or horizons, in a soil. The profile extends from the surface down into the unconsolidated material in which the soil formed or from the surface down to bedrock. The unconsolidated material is devoid of roots and other living organisms and has not been changed by other biological activity. Currently, soils are mapped according to the boundaries of major land resource areas (MLRAs). MLRAs are geographically associated land resource units that share common characteristics related to physiography, geology, climate, water resources, soils, biological resources, and land uses (USDA, 2006). Soil survey areas typically consist of parts of one or more MLRA. The soils and miscellaneous areas in a survey area occur in an orderly pattern that is related to the geology, landforms, relief, climate, and natural vegetation of the area. Each kind of soil and miscellaneous area is associated with a particular kind of landform or with a segment of the landform. By observing the soils and miscellaneous areas in the survey area and relating their position to specific segments of the landform, a soil scientist develops a concept, or model, of how they were formed. Thus, during mapping, this model enables the soil scientist to predict with a considerable degree of accuracy the kind of soil or miscellaneous area at a specific location on the landscape. Commonly, individual soils on the landscape merge into one another as their characteristics gradually change. To construct an accurate soil map, however, soil scientists must determine the boundaries between the soils. They can observe only a limited number of soil profiles. Nevertheless, these observations, supplemented by an understanding of the soil-vegetation-landscape relationship, are sufficient to verify predictions of the kinds of soil in an area and to determine the boundaries. Soil scientists recorded the characteristics of the soil profiles that they studied. They noted soil color, texture, size and shape of soil aggregates, kind and amount of rock fragments, distribution of plant roots, reaction, and other features that enable them to identify soils. After describing the soils in the survey area and determining their properties, the soil scientists assigned the soils to taxonomic classes (units). Taxonomic classes are concepts. Each taxonomic class has a set of soil characteristics with precisely defined limits. The classes are used as a basis for comparison to classify soils systematically. Soil taxonomy, the system of taxonomic classification used in the United States, is based mainly on the kind and character of soil properties and the arrangement of horizons within the profile. After the soil 5 scientists classified and named the soils in the survey area, they compared the individual soils with similar soils in the same taxonomic class in other areas so that they could confirm data and assemble additional data based on experience and research. The objective of soil mapping is not to delineate pure map unit components; the objective is to separate the landscape into landforms or landform segments that have similar use and management requirements. Each map unit is defined by a unique combination of soil components and/or miscellaneous areas in predictable proportions. Some components may be highly contrasting to the other components of the map unit. The presence of minor components in a map unit in no way diminishes the usefulness or accuracy of the data. The delineation of such landforms and landform segments on the map provides sufficient information for the development of resource plans. If intensive use of small areas is planned, onsite investigation is needed to define and locate the soils and miscellaneous areas. Soil scientists make many field observations in the process of producing a soil map. The frequency of observation is dependent upon several factors, including scale of mapping, intensity of mapping, design of map units, complexity of the landscape, and experience of the soil scientist. Observations are made to test and refine the soil-landscape model and predictions and to verify the classification of the soils at specific locations. Once the soil-landscape model is refined, a significantly smaller number of measurements of individual soil properties are made and recorded. These measurements may include field measurements, such as those for color, depth to bedrock, and texture, and laboratory measurements, such as those for content of sand, silt, clay, salt, and other components. Properties of each soil typically vary from one point to another across the landscape. Observations for map unit components are aggregated to develop ranges of characteristics for the components. The aggregated values are presented. Direct measurements do not exist for every property presented for every map unit component. Values for some properties are estimated from combinations of other properties. While a soil survey is in progress, samples of some of the soils in the area generally are collected for laboratory analyses and for engineering tests. Soil scientists interpret the data from these analyses and tests as well as the field-observed characteristics and the soil properties to determine the expected behavior of the soils under different uses. Interpretations for all of the soils are field tested through observation of the soils in different uses and under different levels of management. Some interpretations are modified to fit local conditions, and some new interpretations are developed to meet local needs. Data are assembled from other sources, such as research information, production records, and field experience of specialists. For example, data on crop yields under defined levels of management are assembled from farm records and from field or plot experiments on the same kinds of soil. Predictions about soil behavior are based not only on soil properties but also on such variables as climate and biological activity. Soil conditions are predictable over long periods of time, but they are not predictable from year to year. For example, soil scientists can predict with a fairly high degree of accuracy that a given soil will have a high water table within certain depths in most years, but they cannot predict that a high water table will always be at a specific level in the soil on a specific date. After soil scientists located and identified the significant natural bodies of soil in the survey area, they drew the boundaries of these bodies on aerial photographs and Custom Soil Resource Report 6 identified each as a specific map unit. Aerial photographs show trees, buildings, fields, roads, and rivers, all of which help in locating boundaries accurately. Custom Soil Resource Report 7 Soil Map The soil map section includes the soil map for the defined area of interest, a list of soil map units on the map and extent of each map unit, and cartographic symbols displayed on the map. Also presented are various metadata about data used to produce the map, and a description of each soil map unit. 8 9 Custom Soil Resource Report Soil Map 4493890 4493920 4493950 4493980 4494010 4494040 4494070 4494100 4493890 4493920 4493950 4493980 4494010 4494040 4494070 4494100 493480 493510 493540 493570 493600 493630 493660 493690 493720 493750 493780 493810 493480 493510 493540 493570 493600 493630 493660 493690 493720 493750 493780 493810 40° 35' 51'' N 105° 4' 37'' W 40° 35' 51'' N 105° 4' 23'' W 40° 35' 44'' N 105° 4' 37'' W 40° 35' 44'' N 105° 4' 23'' W N Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 13N WGS84 0 50 100 200 300 Feet 0 20 40 80 120 Meters Map Scale: 1:1,530 if printed on A landscape (11" x 8.5") sheet. Soil Map may not be valid at this scale. MAP LEGEND MAP INFORMATION Area of Interest (AOI) Area of Interest (AOI) Soils Soil Map Unit Polygons Soil Map Unit Lines Soil Map Unit Points Special Point Features Blowout Borrow Pit Clay Spot Closed Depression Gravel Pit Gravelly Spot Landfill Lava Flow Marsh or swamp Mine or Quarry Miscellaneous Water Perennial Water Rock Outcrop Saline Spot Sandy Spot Severely Eroded Spot Sinkhole Slide or Slip Sodic Spot Spoil Area Stony Spot Very Stony Spot Wet Spot Other Special Line Features Water Features Streams and Canals Transportation Rails Interstate Highways US Routes Major Roads Local Roads Background Aerial Photography The soil surveys that comprise your AOI were mapped at 1:24,000. Warning: Soil Map may not be valid at this scale. Enlargement of maps beyond the scale of mapping can cause misunderstanding of the detail of mapping and accuracy of soil line placement. The maps do not show the small areas of contrasting soils that could have been shown at a more detailed scale. Please rely on the bar scale on each map sheet for map measurements. Source of Map: Natural Resources Conservation Service Web Soil Survey URL: Coordinate System: Web Mercator (EPSG:3857) Maps from the Web Soil Survey are based on the Web Mercator projection, which preserves direction and shape but distorts distance and area. A projection that preserves area, such as the Albers equal-area conic projection, should be used if more Map Unit Legend Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI 73 Nunn clay loam, 0 to 1 percent slopes 3.0 30.5% 81 Paoli fine sandy loam, 0 to 1 percent slopes 0.9 8.8% 105 Table Mountain loam, 0 to 1 percent slopes 6.0 60.7% Totals for Area of Interest 9.8 100.0% Map Unit Descriptions The map units delineated on the detailed soil maps in a soil survey represent the soils or miscellaneous areas in the survey area. The map unit descriptions, along with the maps, can be used to determine the composition and properties of a unit. A map unit delineation on a soil map represents an area dominated by one or more major kinds of soil or miscellaneous areas. A map unit is identified and named according to the taxonomic classification of the dominant soils. Within a taxonomic class there are precisely defined limits for the properties of the soils. On the landscape, however, the soils are natural phenomena, and they have the characteristic variability of all natural phenomena. Thus, the range of some observed properties may extend beyond the limits defined for a taxonomic class. Areas of soils of a single taxonomic class rarely, if ever, can be mapped without including areas of other taxonomic classes. Consequently, every map unit is made up of the soils or miscellaneous areas for which it is named and some minor components that belong to taxonomic classes other than those of the major soils. Most minor soils have properties similar to those of the dominant soil or soils in the map unit, and thus they do not affect use and management. These are called noncontrasting, or similar, components. They may or may not be mentioned in a particular map unit description. Other minor components, however, have properties and behavioral characteristics divergent enough to affect use or to require different management. These are called contrasting, or dissimilar, components. They generally are in small areas and could not be mapped separately because of the scale used. Some small areas of strongly contrasting soils or miscellaneous areas are identified by a special symbol on the maps. If included in the database for a given area, the contrasting minor components are identified in the map unit descriptions along with some characteristics of each. A few areas of minor components may not have been observed, and consequently they are not mentioned in the descriptions, especially where the pattern was so complex that it was impractical to make enough observations to identify all the soils and miscellaneous areas on the landscape. The presence of minor components in a map unit in no way diminishes the usefulness or accuracy of the data. The objective of mapping is not to delineate pure taxonomic classes but rather to separate the landscape into landforms or Custom Soil Resource Report 11 landform segments that have similar use and management requirements. The delineation of such segments on the map provides sufficient information for the development of resource plans. If intensive use of small areas is planned, however, onsite investigation is needed to define and locate the soils and miscellaneous areas. An identifying symbol precedes the map unit name in the map unit descriptions. Each description includes general facts about the unit and gives important soil properties and qualities. Soils that have profiles that are almost alike make up a soil series. Except for differences in texture of the surface layer, all the soils of a series have major horizons that are similar in composition, thickness, and arrangement. Soils of one series can differ in texture of the surface layer, slope, stoniness, salinity, degree of erosion, and other characteristics that affect their use. On the basis of such differences, a soil series is divided into soil phases. Most of the areas shown on the detailed soil maps are phases of soil series. The name of a soil phase commonly indicates a feature that affects use or management. For example, Alpha silt loam, 0 to 2 percent slopes, is a phase of the Alpha series. Some map units are made up of two or more major soils or miscellaneous areas. These map units are complexes, associations, or undifferentiated groups. A complex consists of two or more soils or miscellaneous areas in such an intricate pattern or in such small areas that they cannot be shown separately on the maps. The pattern and proportion of the soils or miscellaneous areas are somewhat similar in all areas. Alpha-Beta complex, 0 to 6 percent slopes, is an example. An association is made up of two or more geographically associated soils or miscellaneous areas that are shown as one unit on the maps. Because of present or anticipated uses of the map units in the survey area, it was not considered practical or necessary to map the soils or miscellaneous areas separately. The pattern and relative proportion of the soils or miscellaneous areas are somewhat similar. Alpha-Beta association, 0 to 2 percent slopes, is an example. An undifferentiated group is made up of two or more soils or miscellaneous areas that could be mapped individually but are mapped as one unit because similar interpretations can be made for use and management. The pattern and proportion of the soils or miscellaneous areas in a mapped area are not uniform. An area can be made up of only one of the major soils or miscellaneous areas, or it can be made up of all of them. Alpha and Beta soils, 0 to 2 percent slopes, is an example. Some surveys include miscellaneous areas. Such areas have little or no soil material and support little or no vegetation. Rock outcrop is an example. Custom Soil Resource Report 12 Larimer County Area, Colorado 73—Nunn clay loam, 0 to 1 percent slopes Map Unit Setting National map unit symbol: 2tlng Elevation: 4,100 to 5,700 feet Mean annual precipitation: 14 to 15 inches Mean annual air temperature: 48 to 52 degrees F Frost-free period: 135 to 152 days Farmland classification: Prime farmland if irrigated Map Unit Composition Nunn and similar soils: 85 percent Minor components: 15 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Nunn Setting Landform: Terraces Landform position (three-dimensional): Tread Down-slope shape: Linear Across-slope shape: Linear Parent material: Pleistocene aged alluvium and/or eolian deposits Typical profile Ap - 0 to 6 inches: clay loam Bt1 - 6 to 10 inches: clay loam Bt2 - 10 to 26 inches: clay loam Btk - 26 to 31 inches: clay loam Bk1 - 31 to 47 inches: loam Bk2 - 47 to 80 inches: loam Properties and qualities Slope: 0 to 1 percent Depth to restrictive feature: More than 80 inches Drainage class: Well drained Runoff class: Medium Capacity of the most limiting layer to transmit water (Ksat): Moderately low to moderately high (0.06 to 0.20 in/hr) Depth to water table: More than 80 inches Frequency of flooding: None Frequency of ponding: None Calcium carbonate, maximum content: 7 percent Maximum salinity: Nonsaline (0.1 to 1.0 mmhos/cm) Sodium adsorption ratio, maximum: 0.5 Available water supply, 0 to 60 inches: High (about 9.1 inches) Interpretive groups Land capability classification (irrigated): 3e Land capability classification (nonirrigated): 4e Hydrologic Soil Group: C Ecological site: R067BY042CO - Clayey Plains Hydric soil rating: No Custom Soil Resource Report 13 Minor Components Heldt Percent of map unit: 10 percent Landform: Terraces Landform position (three-dimensional): Tread Down-slope shape: Linear Across-slope shape: Linear Ecological site: R067BY042CO - Clayey Plains Hydric soil rating: No Wages Percent of map unit: 5 percent Landform: Terraces Landform position (three-dimensional): Tread Down-slope shape: Linear Across-slope shape: Linear Ecological site: R067BY002CO - Loamy Plains Hydric soil rating: No 81—Paoli fine sandy loam, 0 to 1 percent slopes Map Unit Setting National map unit symbol: jpxx Elevation: 4,800 to 5,600 feet Mean annual precipitation: 13 to 15 inches Mean annual air temperature: 48 to 50 degrees F Frost-free period: 135 to 150 days Farmland classification: Prime farmland if irrigated Map Unit Composition Paoli and similar soils: 85 percent Minor components: 15 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Paoli Setting Landform: Stream terraces Landform position (three-dimensional): Tread Down-slope shape: Linear Across-slope shape: Linear Parent material: Alluvium Typical profile H1 - 0 to 30 inches: fine sandy loam H2 - 30 to 60 inches: fine sandy loam Properties and qualities Slope: 0 to 1 percent Custom Soil Resource Report 14 Depth to restrictive feature: More than 80 inches Drainage class: Well drained Runoff class: Very low Capacity of the most limiting layer to transmit water (Ksat): High (2.00 to 6.00 in/hr) Depth to water table: More than 80 inches Frequency of flooding: None Frequency of ponding: None Calcium carbonate, maximum content: 15 percent Maximum salinity: Nonsaline to very slightly saline (0.0 to 2.0 mmhos/cm) Available water supply, 0 to 60 inches: Moderate (about 8.7 inches) Interpretive groups Land capability classification (irrigated): 1 Land capability classification (nonirrigated): 3c Hydrologic Soil Group: A Ecological site: R067BY036CO - Overflow Hydric soil rating: No Minor Components Caruso Percent of map unit: 6 percent Ecological site: R067BY036CO - Overflow Hydric soil rating: No Table mountain Percent of map unit: 6 percent Ecological site: R067BY036CO - Overflow Hydric soil rating: No Fluvaquentic haplustolls Percent of map unit: 3 percent Landform: Terraces Hydric soil rating: Yes 105—Table Mountain loam, 0 to 1 percent slopes Map Unit Setting National map unit symbol: jpty Elevation: 4,800 to 5,600 feet Mean annual precipitation: 13 to 15 inches Mean annual air temperature: 48 to 50 degrees F Frost-free period: 135 to 150 days Farmland classification: Prime farmland if irrigated Map Unit Composition Table mountain and similar soils: 85 percent Minor components: 15 percent Estimates are based on observations, descriptions, and transects of the mapunit. Custom Soil Resource Report 15 Description of Table Mountain Setting Landform: Stream terraces, flood plains Landform position (three-dimensional): Tread Down-slope shape: Linear Across-slope shape: Linear Parent material: Alluvium Typical profile H1 - 0 to 36 inches: loam H2 - 36 to 60 inches: clay loam Properties and qualities Slope: 0 to 1 percent Depth to restrictive feature: More than 80 inches Drainage class: Well drained Runoff class: Low Capacity of the most limiting layer to transmit water (Ksat): Moderately high to high (0.60 to 2.00 in/hr) Depth to water table: More than 80 inches Frequency of flooding: None Frequency of ponding: None Calcium carbonate, maximum content: 15 percent Maximum salinity: Nonsaline to very slightly saline (0.0 to 2.0 mmhos/cm) Sodium adsorption ratio, maximum: 5.0 Available water supply, 0 to 60 inches: High (about 9.8 inches) Interpretive groups Land capability classification (irrigated): 1 Land capability classification (nonirrigated): 3c Hydrologic Soil Group: B Ecological site: R049XY036CO - Overflow Hydric soil rating: No Minor Components Caruso Percent of map unit: 7 percent Hydric soil rating: No Fluvaquentic haplustolls Percent of map unit: 4 percent Landform: Terraces Hydric soil rating: Yes Paoli Percent of map unit: 4 percent Hydric soil rating: No Custom Soil Resource Report 16 Soil Information for All Uses Soil Properties and Qualities The Soil Properties and Qualities section includes various soil properties and qualities displayed as thematic maps with a summary table for the soil map units in the selected area of interest. A single value or rating for each map unit is generated by aggregating the interpretive ratings of individual map unit components. This aggregation process is defined for each property or quality. Soil Qualities and Features Soil qualities are behavior and performance attributes that are not directly measured, but are inferred from observations of dynamic conditions and from soil properties. Example soil qualities include natural drainage, and frost action. Soil features are attributes that are not directly part of the soil. Example soil features include slope and depth to restrictive layer. These features can greatly impact the use and management of the soil. Hydrologic Soil Group 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. 17 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. Custom Soil Resource Report 18 19 Custom Soil Resource Report Map—Hydrologic Soil Group 4493890 4493920 4493950 4493980 4494010 4494040 4494070 4494100 4493890 4493920 4493950 4493980 4494010 4494040 4494070 4494100 493480 493510 493540 493570 493600 493630 493660 493690 493720 493750 493780 493810 493480 493510 493540 493570 493600 493630 493660 493690 493720 493750 493780 493810 40° 35' 51'' N 105° 4' 37'' W 40° 35' 51'' N 105° 4' 23'' W 40° 35' 44'' N 105° 4' 37'' W 40° 35' 44'' N 105° 4' 23'' W N Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 13N WGS84 0 50 100 200 300 Feet 0 20 40 80 120 Meters Map Scale: 1:1,530 if printed on A landscape (11" x 8.5") 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 Table—Hydrologic Soil Group Map unit symbol Map unit name Rating Acres in AOI Percent of AOI 73 Nunn clay loam, 0 to 1 percent slopes C 3.0 30.5% 81 Paoli fine sandy loam, 0 to 1 percent slopes A 0.9 8.8% 105 Table Mountain loam, 0 to 1 percent slopes B 6.0 60.7% Totals for Area of Interest 9.8 100.0% Rating Options—Hydrologic Soil Group Aggregation Method: Dominant Condition Component Percent Cutoff: None Specified Tie-break Rule: Higher Custom Soil Resource Report 21 References American Association of State Highway and Transportation Officials (AASHTO). 2004. Standard specifications for transportation materials and methods of sampling and testing. 24th edition. American Society for Testing and Materials (ASTM). 2005. Standard classification of soils for engineering purposes. ASTM Standard D2487-00. Cowardin, L.M., V. Carter, F.C. Golet, and E.T. LaRoe. 1979. Classification of wetlands and deep-water habitats of the United States. U.S. Fish and Wildlife Service FWS/OBS-79/31. Federal Register. July 13, 1994. Changes in hydric soils of the United States. Federal Register. September 18, 2002. Hydric soils of the United States. Hurt, G.W., and L.M. Vasilas, editors. Version 6.0, 2006. Field indicators of hydric soils in the United States. National Research Council. 1995. Wetlands: Characteristics and boundaries. Soil Survey Division Staff. 1993. Soil survey manual. Soil Conservation Service. U.S. Department of Agriculture Handbook 18. http://www.nrcs.usda.gov/wps/portal/ nrcs/detail/national/soils/?cid=nrcs142p2_054262 Soil Survey Staff. 1999. Soil taxonomy: A basic system of soil classification for making and interpreting soil surveys. 2nd edition. Natural Resources Conservation Service, U.S. Department of Agriculture Handbook 436. http:// www.nrcs.usda.gov/wps/portal/nrcs/detail/national/soils/?cid=nrcs142p2_053577 Soil Survey Staff. 2010. Keys to soil taxonomy. 11th edition. U.S. Department of Agriculture, Natural Resources Conservation Service. http:// www.nrcs.usda.gov/wps/portal/nrcs/detail/national/soils/?cid=nrcs142p2_053580 Tiner, R.W., Jr. 1985. Wetlands of Delaware. U.S. Fish and Wildlife Service and Delaware Department of Natural Resources and Environmental Control, Wetlands Section. United States Army Corps of Engineers, Environmental Laboratory. 1987. Corps of Engineers wetlands delineation manual. Waterways Experiment Station Technical Report Y-87-1. United States Department of Agriculture, Natural Resources Conservation Service. National forestry manual. http://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/ home/?cid=nrcs142p2_053374 United States Department of Agriculture, Natural Resources Conservation Service. National range and pasture handbook. http://www.nrcs.usda.gov/wps/portal/nrcs/ detail/national/landuse/rangepasture/?cid=stelprdb1043084 22 United States Department of Agriculture, Natural Resources Conservation Service. National soil survey handbook, title 430-VI. http://www.nrcs.usda.gov/wps/portal/ nrcs/detail/soils/scientists/?cid=nrcs142p2_054242 United States Department of Agriculture, Natural Resources Conservation Service. 2006. Land resource regions and major land resource areas of the United States, the Caribbean, and the Pacific Basin. U.S. Department of Agriculture Handbook 296. http://www.nrcs.usda.gov/wps/portal/nrcs/detail/national/soils/? cid=nrcs142p2_053624 United States Department of Agriculture, Soil Conservation Service. 1961. Land capability classification. U.S. Department of Agriculture Handbook 210. http:// www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/nrcs142p2_052290.pdf Custom Soil Resource Report 23 NORTHERNENGINEERING.COM | 970.221.4158 FINAL DRAINAGE REPORT: POWERHOUSE 2 FORT COLLINS | GREELEY APPENDIX MAP POCKET EXHIBITS AS LISTED ON TABLE OF CONTENTS EAST VINE DRIVE NORTH COLLEGE AVENUE LAKE CANAL T VAULT F.O. CONTROL IRR CONTROL IRR GAS / / / / / / / / / / / / / / / / GAS LOT 1 BRUSH MOBILE HOME P.U.D. (740 N. COLLEGE) LOT 2 BRUSH MOBILE HOME P.U.D. (704 N. COLLEGE) LOT 3 BRUSH MOBILE HOME P.U.D. (108 E. VINE) LOT 4 (202 E. VINE) EAST VINE DRIVE NORTH COLLEGE AVENUE LAKE CANAL T VAULT F.O. CONTROL IRR CONTROL IRR GAS / / / / / / / / / / / / / / / / GAS LOT 1 BRUSH MOBILE HOME P.U.D. (740 N. COLLEGE) TF LOT 2 BRUSH MOBILE HOME P.U.D. (704 N. COLLEGE) LOT 3 BRUSH MOBILE HOME P.U.D. (108 E. VINE) LOT 4 (202 E. VINE) ROOFTOP CONCRETE ASPHALT D D D ST T VAULT F.O. F.O. D GAS X X OHU OHU OHU D F E S LID MH / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / F E S F E S F E S ST ST ST GAS D CTV CTV CTV CTV CTV CTV CTV CTV CTV CTV TF TF TF EM GM G UGE UGE UGE UGE S UD UD UD UD UD UD UD UD UD UD UD UD UD UD UD UD UD UD 1 1 JEROME STREET LLC, 216 E OAK ST JEROME STREET STATION LLC, 742 N COLLEGE AVE LMC VENTURES LLC, 742 N COLLEGE AVE CITY OF FORT COLLINS 405 N COLLEGE AVE MORAK KAREN LLC 622 N COLLEGE AVE CITY OF FORT COLLINS, 740 N COLLEGE AVE FORT COLLINS 1d 4 3b 2 5 6 8 10 11 12 co1 w8 w10 w11 7 9 1d 1.80 ac 2 0.61 ac 6 0.36 ac 3b 0.39 ac W8 0.63 ac 12 0.14 ac 9 0.14 ac 11 0.05 ac Co1 0.43 ac 8 0.12 ac 10 0.03 ac 4 0.29 ac 5 0.16 ac 7 0.11 ac W10 1.50 ac W11 0.89 ac VINE DRIVE COLLEGE AVENUE JEROME STREET 100 YR FLOOD PLAIN (CURRENT EFFECTIVE) 500 YR FLOOD PLAIN (CURRENT EFFECTIVE) 100 YR FLOOD PLAIN (CURRENT EFFECTIVE) 100 YR FLOOD PLAIN (CURRENT EFFECTIVE) 500 YR FLOOD PLAIN (CURRENT EFFECTIVE) 100 YR FLOOD PLAIN (CURRENT EFFECTIVE) 500 YR FLOOD PLAIN (CURRENT EFFECTIVE) 100 YR FLOOD PLAIN (CURRENT EFFECTIVE) 500 YR FLOOD PLAIN (CURRENT EFFECTIVE) 100 YR FLOOD PLAIN (CURRENT EFFECTIVE) 1a 0.05 ac 1b 0.08 ac 1c 0.48 ac 3a 0.01 ac 3c 0.05 ac 1a 1b 1c 3a 3c PROPERTY BOUNDARY PROPERTY BOUNDARY WQ1 - OUTLET STRUCTURE A PROPOSED STORM LINE PROPOSED STORM INLET (TYP.) EXISTING STORM LINE EXISTING INLET PROPOSED STORM INLET (TYP.) PROPOSED POND OUTLET STRUCTURE B DETENTION POND 1 WQCV VOLUME = 0.03 AC-FT TOTAL VOLUME REQUIRED = 0.26 AC-FT MAXIMUM RELEASE RATE = 11.50 CFS OUTLET IN. EL. = 4958.89 WQCV WATER SURFACE EL. = 4958.95 100-YR. WATER SURFACE EL. = 4960.36 FREEBOARD = 0.14 FT TOP OF BERM EL. = 4960.50 PROPOSED COMBINATION INLET PROPOSED OVERFLOW STRUCTURE POND OUTFALL A SEE SHEET ST1 POND OUTFALL B SEE SHEET ST1 RAIN GARDEN 1 SEE SHEET RG1 STORM DRAIN D SEE SHEET ST3 SOUTH RAIN GARDEN 1 SEE SHEET RG2 SOUTH RAIN GARDEN 2 SEE SHEET RG2 SOUTH RAIN GARDEN 3 SEE SHEET RG2 STORM DRAIN C SEE SHEET ST3 STORM DRAIN E SEE SHEET OU1 STORM DRAIN F SEE SHEET OU1 STORM DRAIN G SEE SHEET OU1 UPHAM FREDERICK M 207 E. VINE DRIVE KUNDLA TODD J 209 E. VINE DRIVE Sheet POWERHOUSE 2 NOT FOR CONSTRUCTION REVIEW SET of 35 ( IN FEET ) 1 inch = ft. 50 0 50 Feet 50 100 150 1. REFER TO THE FINAL DRAINAGE REPORT, DATED DECEMBER 14, 2022 FOR ADDITIONAL INFORMATION. 2. PORTIONS OF THIS PROPERTY ARE LOCATED IN THE FEMA REGULATED, 100 YEAR AND 500 YEAR POUDRE RIVER FLOODPLAIN. ANY DEVELOPMENT WITHIN THE FLOODPLAIN MUST COMPLY WITH THE SAFETY REGULATIONS OF CHAPTER 10 OF CITY MUNICIPAL CODE. 3. ANY CONSTRUCTION ACTIVITIES IN THE FLOOD FRINGE (E.G. STRUCTURES, SIDEWALK OR CURB & GUTTER INSTALLATION/REPLACEMENT, UTILITY WORK, LANDSCAPING, ETC.) MUST BE PRECEDED BY AN APPROVED FLOODPLAIN USE PERMIT, THE APPROPRIATE PERMIT APPLICATION FEES, AND APPROVED PLANS. 4. CONSTRUCTION OF RESIDENTIAL AND/OR MIXED_USE STRUCTURES IS PROHIBITED IN THE POUDRE RIVER 100_YEAR FLOODPLAIN. 5. OUTSIDE STORAGE OF EQUIPMENT OR FLOATABLE MATERIALS WHETHER PERMANENT OR TEMPORARY IS PROHIBITED IN THE 100_YEAR FLOODPLAIN. 6. THE APPLICANT ACKNOWLEDGES THAT THIS SITE DEVELOPMENT PLAN DOES NOT COMPLY WITH THE CURRENT REGULATORY FLOODPLAIN. PERMITS CANNOT BE ISSUED FOR RESIDENTIAL STRUCTURES IN THE REGULATORY FLOODPLAIN UNTIL A LOMR IS APPROVED THROUGH FEMA. IT IS AT OUR OWN RISK THAT WE CONTINUE THROUGH THE PLANNING PROCESS. 6. CRITICAL FACILITIES ARE PROHIBITED IN THE FLOODPLAIN, INCLUDING HAZARDOUS MATERIAL, GOVERNMENT SERVICES, ESSENTIAL SERVICES AND AT-RISK POPULATION CRITICAL FACILITIES. THIS INCLUDES SCHOOLS AND AFTER SCHOOL PROGRAMS/DAY CAMPS FOR GRADES K-12. 7. THE QUANTITIES LISTED BELOW AND THE REMOVAL OF HYDROGEN STORAGE FROM THE SITE, WILL REMOVE THE DESIGNATION OF A “CRITICAL FACILITY', AS PER DEFINED BY CHAPTER 10 OF CITY CODE, FROM THE PROJECT. MATERIAL STORAGE RESTRICTIONS WILL BE REMOVED WITH THE APPROVAL OF THE LOMR. THE FOLLOWING OUTLINES THE HANDLING AND STORAGE PROCESSES OF HYDROGEN FOR RESEARCH PROCEDURES ANTICIPATED AT THE PROPOSED POWERHOUSE II FACILITY: · HYDROGEN PRODUCED BY HYDROLYSIS OR SIMILAR METHOD WILL BE DISPOSED OF AS PRODUCED VIA VENTING OUTDOORS (AS PER ANY CODE REQUIREMENTS), BURNED IN OUTDOORS IN A NON-VISIBLE FLARE, CONSUMED BY FUEL CELL OR SIMILAR DEVICE. · ONSITE STORAGE OF HYDROGEN WILL REMAIN AT OR BELOW QUANTITIES REGULATED BY INTERNATIONAL FIRE SAFETY CODE OR “HOUSEHOLD LEVELS” · HYDROGEN FUELED VEHICLES, SUCH AS AUTOMOBILES, LIGHT AND MEDIUM DUTY TRUCKS, AND TRANSIT BUSES WILL BE TESTED ONSITE AND ADHERE TO ALL FIRE SAFETY CODES AND DOT REGULATIONS REGARDING HYDROGEN FUELED VEHICLES. NO VEHICLES WILL BE STORED OUTSIDE OVERNIGHT PER THE FLOATABLE MATERIALS REQUIREMENTS IN CHAPTER 10 OF CITY CODE. · H2 STORAGE TANKS WILL REMAIN AT POWERHOUSE I UNTIL APPROVAL OF THE LOMR. FLAMMABLE MATERIALS: · ACETYLENE : 1 COMMERCIAL CYLINDER AT 300 OR LESS STD. CU. FT. VOLUME. · OXYGEN : 1 COMMERCIAL CYLINDER AT 300 OR LESS STD. CU. FT. VOLUME. NON-REACTIVE GASES: · COMPRESSED AIR : 500 GAL. TANK · COMPRESSED NITROGEN : 2000 L. CRYOGENIC TANK, LIQUID · COMPRESSED ARGON : 2000 L. CRYOGENIC TANK, LIQUID · COMPRESSED HELIUM : <20 - 300 STD. CU FT, STEEL CYLINDERS · COMPRESSED ARGON : <20 - 300 STD. CU FT, STEEL CYLINDERS · COMPRESSED CO2 : <20 - 300 STD. CU FT, STEEL CYLINDERS 8. THE PROPOSED POWERHOUSE II BUILDING IS PROJECTED TO HOUSE SEVERAL TYPES OF ORGANIZATIONS: RETAIL, PRIVATE COMPANIES WORKING IN ENERGY INDUSTRY, AND COLORADO STATE UNIVERSITY (CSU) FUNCTIONS RELATING TO SPONSORED RESEARCH. THE CSU SPACE WILL BE ASSIGNED TO RESEARCHERS TO CONDUCT SPONSORED RESEARCH FOR INDUSTRY AND GOVERNMENT (LOCAL, CITY, STATE AND FEDERAL) SPONSORS. THESE SPACES WILL NOT BE USED FOR TRADITIONAL EDUCATIONAL FUNCTIONS SUCH AS CLASSROOM INSTRUCTION OR LABORATORY INSTRUCTION. WHILE UNIVERSITY EMPLOYEES (RESEARCHERS, STAFF, AND STUDENT EMPLOYEES) WILL BE USING THE SPACE THEY WILL NOT BE ENGAGED IN INSTRUCTIONAL ACTIVITIES. GOVERNMENT SERVICES FACILITIES INCLUDE ESSENTIAL STRUCTURES SUCH AS DORMITORIES, OFFICES, CLASSROOMS, AND LABORATORIES FOR PUBLIC HIGHER EDUCATION FACILITIES. POWERHOUSE II WILL NOT BE USED FOR DORMITORY HOUSING. NOR WILL IT HAVE INSTRUCTIONAL CLASSROOMS AND THE LABORATORY AND OFFICE SPACES WILL BE USED SOLELY FOR SPONSORED RESEARCH ACTIVITIES. GIVEN THIS DEFINITION AND PURPOSES, POWERHOUSE II SHOULD NOT BE CLASSIFIED AS A GOVERNMENT SERVICES FACILITY PER CHAPTER 10 OF CITY CODE AND THE RESTRICTIONS ASSOCIATED WITH THIS DESIGNATION. DR1 DRAINAGE EXHIBIT DEVELOPED 34 NORTH SWALE SECTIONS SWALE SUMMARY TABLE SWALE ID MIN D MIN TW S1 (n:1) S2 (n:1) Q 1 - 1 1.16 26.68 15.0 8.0 11.25 PROPOSED CONTOUR PROPOSED STORM SEWER PROPOSED SWALE EXISTING CONTOUR PROPOSED CURB & GUTTER PROPERTY BOUNDARY PROPOSED INLET A DESIGN POINT FLOW ARROW DRAINAGE BASIN LABEL DRAINAGE BASIN BOUNDARY PROPOSED SWALE SECTION 1 1 NOTES: A LEGEND: NATURAL HABITAT BUFFER ZONE (NHBZ) PROPOSED POND WATER SURFACE ELEVATION CALL 2 BUSINESS DAYS IN ADVANCE BEFORE YOU DIG, GRADE, OR EXCAVATE FOR THE MARKING OF UNDERGROUND MEMBER UTILITIES. CALL UTILITY NOTIFICATION CENTER OF COLORADO Know what'sbelow. Call before you dig. R C2 C100 Q2 (cfs) Q100 (cfs) C2 C100 Q2 (cfs) Q100 (cfs) PAVERS SURFACE AREA (SF) % IMPERV. IMPERV. AREA (SF) 8,925 5,048 43,188 0 90 100 100 40 TOTALS 201,281 TOTAL= 109,526 EXISTING P:\207-030\DWG\DRNG\207-030_DRNG-IMP.DWG POWERHOUSE 2 FORT COLLINS COLORADO DESCRIPTION EXISTING VS. PROPOSED IMPERVIOUS AREA - BASIN A DRAWN BY C. ORTIZ DATE SEPTEMBER 9th, 2022 PROJECT 207-030 DR-A SCALE DRAWING 1"=100' GRAVEL 133,145 40 53,258 LANDSCAPE 10,975 0 0 8,033 5,048 43,188 0 TOTAL PERCENT IMPERVIOUS = 54% PROPOSED ROOFTOP CONCRETE PAVERS GRAVEL SURFACE AREA (SF) % IMPERV. IMPERV. AREA (SF) TOTALS 206,172 TOTAL= 114,855 LANDSCAPE ASPHALT 39,028 35,938 33,414 6,446 90% 100% 100% 40% 12,934 40% 5,173 71,846 0% 0 35,125 35,938 33,414 2,578 TOTAL PERCENT IMPERVIOUS = 56% GRAVEL W/ SOLAR 6,567 40% 2,627 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. Custom Soil Resource Report 20 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. Custom Soil Resource Report 10 742 N COLLEGE AVE CITY OF FORT COLLINS 405 N COLLEGE AVE MORAK KAREN LLC 622 N COLLEGE AVE CITY OF FORT COLLINS, 740 N COLLEGE AVE TF TF TF EM GM POWERHOUSE II SHEET NO: P:\207-030\DWG\DRNG\207-030_LID.DWG DRAWING REFERENCE: LID TREATMENT EXHIBIT C. Ortiz 1" = 80' DECEMBER 2022 LID-1 DRAWN BY: SCALE: ISSUED: NOTES 1. FOR LID RAIN GARDENS CALCULATIONS PLEASE REFER TO THE FINAL DRAINAGE REPORT, DATED DECEMBER 14, 2022. 2. REFER TO UTILITY PLANS FOR POWERHOUSE II FOR ADDITIONAL GRADING AND UTILITY INFORMATION. 3. REFER TO LANDSCAPE PLANS FOR ADDITIONAL INFORMATION ON HARDSCAPES. 4. REFER TO DRAINAGE EXHIBIT SHEET DR1 OF UTILITY PLANS FOR SOIL AMENDMENT NOTES LEGEND PROPOSED CONTOUR PROPOSED STORM SEWER PROPOSED SWALE EXISTING CONTOUR PROPOSED CURB & GUTTER PROPERTY BOUNDARY PROPOSED INLET RAIN GARDEN TREATMENT AREA NORTH ( IN FEET ) 0 1 INCH = 80 FEET 80 80 EXTENDED DETENTION TREATMENT AREA UNTREATED AREA GRAVEL TREATMENT AREA Powerhouse 2 On-Site LID Treatment Project Summary Total Impervious Area 134,735 sf Target Treatment Percentage 75% Minimum Area to be Treated by LID measures 101,051 sf Treated Impervious Areas by Treatment Method Rain Garden 86,629 sf Gravel Paving 31,096 sf Total Treated Impervious Areas 117,725 sf Percent Total Project Area Treated 87.4% WP CDOT/Denver 13 Combination Override Depths 1 Discharge (cfs) Stage (ft) Stage - Discharge Curves Weir Flow Orifice Flow Q = 3 . 0 P H 1 . 5 Q = 0 . 67 A ( 2 gH ) 0 . 5 Stage (ft) Stage - Discharge Curves Weir Flow Orifice Flow Q = 3 . 0 P H 1 . 5 Q = 0 . 67 A ( 2 gH ) 0 . 5 Q = 3 . 0 P H 1 . 5 Q = 0 . 67 A ( 2 gH ) 0 . 5 Orifice Flow Q = 3 . 0 P H 1 . 5 Q = 0 . 67 A ( 2 gH ) 0 . 5 /100) Water Quality Capture Volume 6 hr 12 hr 24 hr 40 hr WQCV = a ( 0.91 i 3 − 1 . 19 i 2 + 0 . 78 i ) WQCV = a ( 0.91 i 3 − 1 . 19 i 2 + 0 . 78 i ) V * A 12 WQCV = 40 hr Date : December 13, 2022 Project Location : Fort Collins, CO. 1 Point Basin Intensity, I, from Fig. 3.4.1 Fort Collins Stormwater Manual. Rational Equation: Q = CiA (Equation 6-1 per MHFD) Area (acres) Tc (Min) Runoff C Date: Fort Collins Project: Location: Calc. By: Combined Basins Information taken from "Drainage, Water Quality and Erosion Control Report for Poudre River Whitewater Park" Information taken from "Drainage, Water Quality and Erosion Control Report for Poudre River Whitewater Park" Information taken from "Drainage, Water Quality and Erosion Control Report for Poudre River Whitewater Park" Basins Not Detain 7 7 27 62.36 61.41 3.53% 3.23 3.23 2.29 28 61.41 60.53 3.18% Swale (8:1) 0.02 8.00 16.12 0.50 11.10 0.04 5.00 5.00 8 8 21 69.97 67.84 10.10% 2.58 2.58 2.14 25 67.84 67.05 3.21% Swale (8:1) 0.04 8.00 16.12 0.50 4.78 0.09 5.00 5.00 9 9 53 67.99 65.10 5.46% 6.95 6.95 6.57 49 65.10 64.37 1.49% Swale (6:1) 0.04 6.00 12.17 0.49 3.24 0.25 7.21 6.82 10 10 5 65.85 63.45 52.86% 0.96 0.96 0.90 4 63.45 61.20 55.01% Swale (8:1) 0.04 8.00 16.12 0.50 19.79 0.00 5.00 5.00 11 11 6 63.42 63.29 2.19% 3.16 3.16 2.98 8 63.29 63.11 2.16% Swale (8:1) 0.04 8.00 16.12 0.50 3.93 0.04 5.00 5.00 12 12 27 63.56 62.85 2.65% 3.53 3.53 2.49 34 62.85 62.50 1.03% Swale (8:1) 0.04 8.00 16.12 0.50 2.71 0.21 5.00 5.00 co1 Co1 34 67.54 66.78 2.23% 3.03 3.03 1.49 179 66.78 65.93 0.47% Gutter 0.02 3.61 19.18 0.19 2.25 1.33 5.00 5.00 w8 W8 Information taken from "Drainage, Water Quality and Erosion Control Report for Poudre River Whitewater Park" w10 W10 Information taken from "Drainage, Water Quality and Erosion Control Report for Poudre River Whitewater Park" w11 W11 Information taken from "Drainage, Water Quality and Erosion Control Report for Poudre River Whitewater Park" 1a, 1b, 1c, 1d (North Rain Garden) 85 69.00 64.32 5.48% 4.23 4.23 2.59 229 60.50 60.41 0.04% Swale (8:1) 0.04 8.00 16.12 0.50 0.53 7.24 11.46 9.83 3a, 3b, 3c (South Rain Garden) ASSUMED A TIME OF CONCENTRATION OF 5 MINUTE FOR ROOF 5.00 5.00 2, 4, 6 to Extended Detention Basin WQ 49 62.04 58.09 8.06% 3.33 3.33 2.37 208 58.09 56.99 0.53% Swale (8:1) 0.04 8.00 16.12 0.50 1.94 1.79 5.12 5.00 1a to 1d, 2, 3a to 3c, 4 and 6 to Detention Pond 85 69.00 64.32 5.48% 4.22 4.22 2.59 229 60.50 60.41 0.04% Swale (8:1) 0.04 8.00 16.12 0.50 0.53 7.24 11.46 9.82 Basins Not Detain Combined Basins DEVELOPED TIME OF CONCENTRATION COMPUTATIONS Overland Flow, Time of Concentration: Maximum Tc: Channelized Flow, Velocity: Channelized Flow, Time of Concentration: Powerhouse 2 Fort Collins C. Ortiz 13-Dec-22 Design Point Basin ID Notes S = Longitudinal Slope, feet/feet R = Hydraulic Radius (feet) n = Roughness Coefficient V = Velocity (ft/sec) WP = Wetted Perimeter (ft) Historic Basins: Developed Basins: Overland Flow Channelized Flow Time of (Equation 3.3-2 per Fort Collins Stormwater Manual) �� = 1.87 1.1 − � ∗ �� � � � � � � = 1.49 � ∗ ��/� ∗ � (Equation 5-4 per Fort Collins Stormwater Manual) �� = � 180 + 10 (Equation 3.3-5 per Fort Collins Stormwater Manual) �� = � � ∗ 60 (Equation 5-5 per Fort Collins Stormwater Manual) 1) Add 4900 to all elevations. 2) Per Fort Collins Stormwater Manual, minimum Tc = 5 min. 3) Assume a water depth of 6" and a typical curb and gutter per Larimer County Urban Street Standard Detail 701 for curb and gutter channelized flow. Assume a water depth of 1', fixed side W10 65,340 1.50 Information taken from "Drainage, Water Quality and Erosion Control Report for Poudre River Whitewater Park" 90% W11 38,768 0.89 Information taken from "Drainage, Water Quality and Erosion Control Report for Poudre River Whitewater Park" 85% 1a, 1b, 1c, 1d (North Rain Garden) 104,808 2.41 0.88 0.56 0.14 0.00 0.82 61% 0.67 0.67 0.67 0.84 3a, 3b, 3c (South Rain Garden) 19,567 0.45 0.07 0.34 0.00 0.00 0.03 85% 0.89 0.89 0.89 1.00 2, 4, 6 to Extended Detention Basin WQ 55,005 1.26 0.53 0.00 0.32 0.00 0.42 53% 0.59 0.59 0.59 0.74 1a to 1d, 2, 3a to 3c, 4 and 6 to Detention Pond 179,381 4.12 1.48 0.91 0.46 0.00 1.27 61% 0.67 0.67 0.67 0.84 Basins Not Detained Lawns and Landscaping: Combined Basins A,B & C 2) Composite Runoff Coefficient adjusted per Table 3.2-3 of the Fort Collins Stormwater Manual (FCSM). Lawns, Clayey Soil, Flat Slope < 2% USDA SOIL TYPE: C Undeveloped: Greenbelts, Agriculture Composite Runoff Coefficient 2 1) Runoff coefficients per Tables 3.2-1 & 3.2 of the FCSM. Percent impervious per Tables 4.1-2 & 4.1-3 of the FCSM. Historic Basins: Developed Basins: DEVELOPED RUNOFF COEFFICIENT CALCULATIONS Asphalt, Concrete Rooftop Gravel Pavers Streets, Parking Lots, Roofs, Alleys, and Drives: Character of Surface: Powerhouse 2 Fort Collins C. Ortiz December 13, 2022 Notes: 1) Basins 1a to 1d and 3a to 3c are draining towards Rain Gardens (LID). 2) Extended Detention Basin WQ, consist of basins draining into detention pond that is not treated by LID. (2, 4, 6) 3) Basin 10 and 11 Drain to Lake Canal. 4) Basin 5 and 7 Drain to Vine Drive. 5) Basin 12 Drain to Jerome St. 6) Basin 8 and Co1 Drain to College Ave.