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HomeMy WebLinkAboutPROSPECT SPORTS CLUB - FDP240002 - SUBMITTAL DOCUMENTS - ROUND 1 - Responses (3)PRELIMINARY DRAINAGE REPORT 19 OLD TOWN SQUARE #238 | FORT COLLINS, CO 80524 | 970-530-4044 | www.unitedcivil.com P ROSPECT S PORTS Lot 5 Prospect Park East P.U.D Fort Collins, CO Prepared for: RB+B Architects, Inc. 315 E. Mountain Ave, Suite 100 Fort Collins, CO 80524 Date: December 20 th , 2023 P RELIMINARY D RAINAGE R EPORT P ROSPECT S PORTS F ORT C OLLINS ,CO 6 U22014_Drainage Report Basin EX1 Basin EX1 represents on-site runoff that drains to the existing property to the south and ultimately to the detention pond within Tract A of the Prospect Park East P.U.D. There is a very small portion of this basin that has existing public concrete sidewalk, but the majority of the existing site is undeveloped. Proposed Basins The following basins provide proposed drainage delineations for the site in its improved condition. Refer to Appendix A for hydrology computations and Appendix B for calculations related to Water Quality, Low Impact Development, and other hydraulic features. Basin A Sub-basins A1-A8 (see Drainage Plans attached) include the area of the site being collected by the proposed storm sewer infrastructure and are a majority of the site. These basins consist of roofs, asphalt and concrete paving, and landscaping. Runoff within these basins is conveyed to grass swales and bioretention ponds via sheet flow, curb, inlets, and storm sewer. Ultimately runoff is conveyed through the proposed storm sewer to the existing lake/pond across Sharp Point and ultimately released to the Cache La Poudre River. Basin OS1 Basin OS1 represents the portion of the proposed site draining offsite to the south undetained. This basin consists of concrete sidewalk, asphalt pavement, and landscaping. In its improved condition, this basin will continue to function as most of the existing site did with conveying flows offsite to the south property and ultimately to the detention pond within Tract A of the Prospect Park East P.U.D. Detention and Water Quality No detention is being provided for the site due to previously discussed site constraints and as documented in the variance request. However, water quality is provided and will be achieved through the use of bioretention ponds per the Fort Collins Stormwater Criteria Manual. Low Impact Development (LID) In December of 2015, Fort Collins City Council adopted the revised Low Impact Development (LID) policy and criteria which requires developments within City limits to meet certain enhanced stormwater treatment requirements in addition to more standard treatment techniques. The proposed development will be required to meet the newly adopted LID criteria which requires the following: -Treat no less than 75% of any newly added impervious area using one or a combination of LID techniques. -Treat no less than 50% of any newly added impervious area using one or a combination of LID techniques when at least 25% of any newly added pavement is provided with permeable pavement. The following measures are implemented with this proposed development: I.Northern Bioretention Pond Basins A6 and A 8.1, combined for 7,540-sf of proposed composite impervious area, are designed to be conveyed to the northern bioretention pond. The proposed impervious area treated through the bioretention ponds includes roof areas, and landscaping. All bioretention ponds will be designed with underdrains which will be conveyed to the proposed storm sewer onsite. It should be noted that groundwater was encountered during boring for geotechnical analysis of the soil in December of 2022. With the bioretention ponds, groundwater would have a negative impact on how the system functions as it relates to water quality and LID purposes. After analyzing groundwater depths in this area, groundwater would be at a depth of approximately 8 feet below existing ground, corresponding to an elevation of 4893.50. The bottom of the northern bioretention pond is at an elevation of 4900.65 and bottom of bioretention media is at an elevation of approximately 4898.15 and approximately 4.5 feet above the groundwater at the time of the borings. It is P RELIMINARY D RAINAGE R EPORT P ROSPECT S PORTS F ORT C OLLINS ,CO 9 U22014_Drainage Report Identifying who is responsible for maintenance of BMPs and ensuring that an adequate budget is allocated for maintenance is critical to the long-term success of BMPs. Maintenance responsibility may be assigned either publicly or privately. For this project, the privately owned BMPs include grass swales and bioretention ponds which are to be maintained by the property owner. Private Storm Sewers There are multiple storm sewer networks proposed with the site improvements and all are proposed to be privately owned systems maintained by the property owner. Several networks including roof drains, storm drains, and underdrain lines for permeable pavers are proposed ultimately with outfalls to the existing pond east of the site. Proposed storm sewer systems are designed to accommodate the flows from the 100-year storm event. Hydraulic computations of these systems will be provided with the final drainage report and design. Private Inlets There are multiple inlets proposed with site improvements, including Nyloplast drain basins and Type R inlets and all are proposed to be privately owned systems maintained by the property owner. One Type R Inlet is designed in sump to capture developed runoff while the other is on grade. On-site drain basins are designed in a sump condition and are designed to convey runoff produced within smaller interior basins to proposed storm sewer and ultimately to the existing lake/pond east of the site. All inlets on the site are sized to provide adequate capacity and convey the 100-year storm event. Hydraulic computations of these systems will be provided with the final drainage report and design. V.EROSION CONTROL A separate Erosion Control Report / Storm Water Management Plan (SWMP) will be prepared for the site in accordance with the Stormwater Discharge Permit for Colorado Department of Public Health and Environment as the site will disturb an area greater than 1-acre. The Erosion Control Report will be completed during the Final Compliance phase of the project and will include more detailed information on the sediment and erosion control items for this project. It is intended that the proposed improvements will comply with Erosion Control Criteria per the FCSCM, and all Erosion Control Materials will be provided with the Final Drainage Report. At a minimum, the following temporary BMP’s will be installed and maintained to control on-site erosion and prevent sediment from traveling off-site during construction: Silt Fence – a woven synthetic fabric that filters runoff. The silt fence is a temporary barrier that is placed at the base of a disturbed area. Vehicle Tracking Control – a stabilized stone pad located at points of ingress and egress on a construction site. The stone pad is designed to reduce the amount of mud transported onto public roads by construction traffic. Riprap – Riprap will be used downstream of all storm sewer outfalls to control erosion of the receiving channels. Inlet Protection – acts as a sediment filter. It is a temporary BMP and requires proper installation and maintenance to ensure their performance. Straw Wattles – wattles act as a sediment filter in swales around inlets. They are a temporary BMP and require proper installation and maintenance to ensure their performance. Slope Protection – Slopes should be terraced using a “tracked” vehicle, run perpendicular to slope to inhibit rill/gulley erosion. The contractor shall store all construction materials and equipment and shall provide maintenance and fueling of equipment in confined areas on-site from which runoff will be contained and filtered. Temporary Best Management Practices (BMP’s) will be inspected by the contractor at a minimum of once every two weeks and after each significant storm event. P RELIMINARY D RAINAGE R EPORT P ROSPECT S PORTS F ORT C OLLINS ,CO 10 U22014_Drainage Report VI.CONCLUSIONS A.COMPLIANCE WITH STANDARDS Storm drainage calculations have followed the guidelines provided by the Urban Storm Drainage Criteria Manuals Volumes 1, 2 and 3 and the City of Fort Collins Stormwater Criteria Manual. Moreover, Chapter 10 of the City Code has been adhered to. Detention Pond A1 also adheres to State Senate Bill 15-212 drain time requirements (refer to Appendix C for calculations). B.DRAINAGE CONCEPT The drainage system has been designed to convey the runoff to the designated design points and the existing public infrastructure in an effective, safe manner. No negative impacts are anticipated to the City of Fort Collins Master Drainage Plan or to downstream properties or infrastructure due to the proposed improvements. C.STORMWATER QUALITY Multiple long-term stormwater quality measures have been selected for the site that will provide treatment of stormwater prior to it to being discharged from the site. For this site this includes grass swales and bioretention ponds. WATER QUALITY Prospect Sports, Fort Collins, CO Required Water Quality Capture Volume Basin Area Area Imperviousness Watershed WQCV WQ Treatment (sf)(acres)(%)(inches)(cf)Method A1 16,107 0.370 16%0.08 129 Biorention Pond A2 4,665 0.107 100%0.40 187 Biorention Pond A3 13,970 0.321 73%0.23 324 Biorention Pond A4 12,396 0.285 72%0.23 283 Biorention Pond A5 16,765 0.385 9%0.05 85 Biorention Pond A6 10,194 0.234 14%0.07 70 Biorention Pond A7 11,082 0.254 7%0.04 42 Biorention Pond A8.1 6,838 0.157 90%0.32 220 Biorention Pond A8.2 17,086 0.392 90%0.32 549 Biorention Pond TOTAL 109,103 2.505 47%0.16 1,739 OS1 6,413 0.147 6%0.04 23 None Northern Pond 17,032 0.391 44%0.15 260 Bioretention Pond Southern Pond 92,071 2.114 48%0.16 1,478 Bioretention Pond Water quality provided based on 12-hour storage Date: 12/18/2023 C:\United Civil Dropbox\Projects\U22014 - Prospect Park East\Reports\Drainage\Calculations\U22014-Drain Calcs National Flood Hazard Layer FIRMette 0 500 1,000 1,500 2,000250 Feet Ü SEE FIS REPORT FOR DETAILED LEGEND AND INDEX MAP FOR FIRM PANEL LAYOUT SPECIAL FLOOD HAZARD AREAS Without Base Flood Elevation (BFE) Zone A, V, A99 With BFE or DepthZone AE, AO, AH, VE, AR Regulatory Floodway 0.2% Annual Chance Flood Hazard, Areas of 1% annual chance flood with average depth less than one foot or with drainage areas of less than one square mileZone X Future Conditions 1% Annual Chance Flood HazardZone X Area with Reduced Flood Risk due to Levee. See Notes.Zone X Area with Flood Risk due to LeveeZone D NO SCREEN Area of Minimal Flood Hazard Zone X Area of Undetermined Flood HazardZone D Channel, Culvert, or Storm Sewer Levee, Dike, or Floodwall Cross Sections with 1% Annual Chance 17.5 Water Surface Elevation Coastal Transect Coastal Transect Baseline Profile Baseline Hydrographic Feature Base Flood Elevation Line (BFE) Effective LOMRs Limit of Study Jurisdiction Boundary Digital Data Available No Digital Data Available Unmapped This map complies with FEMA's standards for the use of digital flood maps if it is not void as described below. The basemap shown complies with FEMA's basemap accuracy standards The flood hazard information is derived directly from the authoritative NFHL web services provided by FEMA. This map was exported on 9/16/2022 at 3:11 PM and does not reflect changes or amendments subsequent to this date and time. The NFHL and effective information may change or become superseded by new data over time. This map image is void if the one or more of the following map elements do not appear: basemap imagery, flood zone labels, legend, scale bar, map creation date, community identifiers, FIRM panel number, and FIRM effective date. Map images for unmapped and unmodernized areas cannot be used for regulatory purposes. Legend OTHER AREAS OF FLOOD HAZARD OTHER AREAS GENERAL STRUCTURES OTHER FEATURES MAP PANELS 8 B 20.2 The pin displayed on the map is an approximate point selected by the user and does not represent an authoritative property location. 1:6,000 105°2'10"W 40°34'13"N 105°1'33"W 40°33'46"N Basemap: USGS National Map: Orthoimagery: Data refreshed October, 2020 This unofficial copy was downloaded on Jul-06-2022 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA National Flood Hazard Layer FIRMette 0 500 1,000 1,500 2,000250 Feet Ü SEE FIS REPORT FOR DETAILED LEGEND AND INDEX MAP FOR FIRM PANEL LAYOUT SPECIAL FLOOD HAZARD AREAS Without Base Flood Elevation (BFE) Zone A, V, A99 With BFE or DepthZone AE, AO, AH, VE, AR Regulatory Floodway 0.2% Annual Chance Flood Hazard, Areas of 1% annual chance flood with average depth less than one foot or with drainage areas of less than one square mileZone X Future Conditions 1% Annual Chance Flood HazardZone X Area with Reduced Flood Risk due to Levee. See Notes.Zone X Area with Flood Risk due to LeveeZone D NO SCREEN Area of Minimal Flood Hazard Zone X Area of Undetermined Flood HazardZone D Channel, Culvert, or Storm Sewer Levee, Dike, or Floodwall Cross Sections with 1% Annual Chance 17.5 Water Surface Elevation Coastal Transect Coastal Transect Baseline Profile Baseline Hydrographic Feature Base Flood Elevation Line (BFE) Effective LOMRs Limit of Study Jurisdiction Boundary Digital Data Available No Digital Data Available Unmapped This map complies with FEMA's standards for the use of digital flood maps if it is not void as described below. The basemap shown complies with FEMA's basemap accuracy standards The flood hazard information is derived directly from the authoritative NFHL web services provided by FEMA. This map was exported on 9/16/2022 at 3:11 PM and does not reflect changes or amendments subsequent to this date and time. The NFHL and effective information may change or become superseded by new data over time. This map image is void if the one or more of the following map elements do not appear: basemap imagery, flood zone labels, legend, scale bar, map creation date, community identifiers, FIRM panel number, and FIRM effective date. Map images for unmapped and unmodernized areas cannot be used for regulatory purposes. Legend OTHER AREAS OF FLOOD HAZARD OTHER AREAS GENERAL STRUCTURES OTHER FEATURES MAP PANELS 8 B 20.2 The pin displayed on the map is an approximate point selected by the user and does not represent an authoritative property location. 1:6,000 105°2'10"W 40°34'13"N 105°1'33"W 40°33'46"N Basemap: USGS National Map: Orthoimagery: Data refreshed October, 2020 OS1 0.15 A6 0.23 A4 0.28 A2 0.11 A3 0.32 A1 0.37 A5 0.38 A7 0.25 A8.2 0.39 A8.1 0.16 SH A R P P O I N T D R I V E PROPOSED BUILDING EAST PROSPEC T R O A D (100' ROW) SOUTHERN POND NORTHERN POND EXISTING TREES TO REMAIN STORMWATER FROM THE WEST STORM SYSTEM TO DRAIN THROUGH TREES AND VEGETATION PA T H : 0'50'100' SCALE: 1" = 50' 25' C: \ U N I T E D C I V I L D R O P B O X \ P R O J E C T S \ U 2 2 0 1 4 - P R O S P E C T P A R K E A S T \ C A D D \ E T \ 2 0 2 3 - 1 2 - 0 7 _ L I D E X H I B I T . D W G 20 2 3 - 1 2 - 0 7 _ L I D E X H I B I T DR A W I N G N A M E : SH E E T S I Z E : 1 1 x 1 7 PROSPECT SPORTS CLUB LID & BMP TREATMENT MAP DATE:December 8, 2023 PREPARED FOR:TCC CORPORATION JOB NUMBER:U22014 NOTE:THIS EXHIBIT WAS PREPARED FOR INFORMATION ONLY AND THE ENGINEER PREPARING THESE PLANS WILL NOT BE RESPONSIBLE FOR UNAUTHORIZED USE OF THEM.SHEET OF1 1 NO R T H 19 OLD TOWN SQUARE #238 | FORT COLLINS, CO 80524 | (970) 530-4044 | www.unitedcivil.com UNITED CIVIL Design Group BASIN BOUNDARY LEGEND NORTHERN BIORETENTION POND SOUTHERN BIORETENTION POND NO SYSTEM PROVIDED UP E. PROSPECT R O A D SH A R P P O I N T D R . EXISTING BUILDING LOT 6 PROSPECT PARK EAST P.U.D. LOT 4 PROSPECT PARK EAST P.U.D. TRACT "A" PROSPECT PARK EAST P.U.D. PROPOSED BUILDING FFE = 4903.50 (NORTH) FFE = 4899.00 (GYM / SOUTH) LOT 5 PROSPECT PARK EAST P.U.D. FLOODPLAIN BFE 100-YEAR FLOOD ELEVATION - 4904 (NAVD 88) DP A6 DP A4 DP A3 DP OS1 DP A1 DP A5 DP A2 DP A7 OS1 0.15 A6 0.23 A4 0.28 A2 0.11 A3 0.32 A1 0.37 A5 0.38 A7 0.25 A8.2 0.39 A8.1 0.16 10' DRAINAGE EASEMENT FLOODPLAIN BFE 100-YEAR FLOOD E L E V A T I O N - 4,900.0 (NAVD 88) FLOODPLAIN BFE 100-YEAR FLOOD ELEVATI O N - 4901 (NAVD 88) FLOODPLAIN C R O S S - S E C T I O N # 208567 100-YR FLOOD E L E V . 4 , 9 0 0 . 0 ( N A V D 8 8 ) GRASS SWALE GRASS SWALE EXISTING LAKE/POND STORM SEWER STORM SEWER POND OUTLET FLARED END SECTION CURB INLET POUDRE RIVER 100-YR FLOODWAY POUDRE RIVER 500-YR FLOODPLAIN LIMITS OF DISTURBANCE LIMITS OF DISTURBANCE AREA INLET POUDRE RIVER 100-YR FLOODPLAIN NORTH BIORETENTION POND SOUTH BIORETENTION POND EXISTING TREES TO REMAIN STORMWATER FROM THE WEST STORM SYSTEM TO DRAIN THROUGH TREES AND VEGETATION 0 30'60' SCALE: 1" = 30' 15' NO R T H 12 / 1 9 / 2 0 2 3 9: 0 5 : 0 6 A M C: \ U N I T E D C I V I L D R O P B O X \ P R O J E C T S \ U 2 2 0 1 4 - P R O S P E C T P A R K E A S T \ C A D D \ C P \ C 5 . 0 0 - D R A I N A G E P L A N . D W G C5 . 0 0 - D R A I N A G E P L A N -- - - -- - - PROPOSED MAJOR CONTOUR PROPOSED MINOR CONTOUR LEGEND EXISTING MAJOR CONTOUR EXISTING MINOR CONTOUR EXISTING PROPERTY BOUNDARY RIGHT OF WAY XX.X X BASIN DESIGNATION BASIN AREA (ACRE) PROPOSED BASIN PROPOSED BASIN LINE 1.THE TOP OF FOUNDATION ELEVATIONS SHOWN ARE THE MINIMUM ELEVATIONS REQUIRED FOR PROTECTION FROM THE 100-YEAR STORM. MINIMUM FINISHED FLOOR ELEVATIONS ABOVE THE 100-YEAR WATER SURFACE IN STREETS, CHANNELS, DITCHES, SWALES, OR OTHER DRAINAGE FACILITIES, AS ILLUSTRATED BY A MASTER GRADING PLAN ARE TO BE SHOWN. NOTES 1.THE FIRST FLOOR OF THE PROPOSED COMMERCIAL BUILDING IS BEING ELEVATED A MINIMUM OF 24-INCHES ABOVE THE BASE FLOOD ELEVATION OR FLOOD PROOFED. REFER TO ARCHITECTURAL PLANS FOR FLOOD PROOFING DETAILS AND SPECIFICATIONS. ALL FLOOD PROOFING MEASURES SHALL ADHERE TO SECTION 10-38 OF CITY CODE AND THE REQUIREMENTS SET FORTH WITHIN THE CITY'S "FLOODPROOFING GUIDELINES". A FLOOD PROOFING CERTIFICATE WILL BE REQUIRED PRIOR TO THE ISSUANCE OF A CERTIFICATE OF OCCUPANCY. 2.ALL SPOT ELEVATIONS AND BASE FLOOD ELEVATIONS AS SHOWN ON THIS DRAWING ARE PER VERTICAL CONTROL DATUM NAVD 88. 3.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. 4.ANY CONSTRUCTION ACTIVITIES IN THE FLOOD FRINGE (E.G. BUILDING OF STRUCTURES, EV CHARGING STATIONS, GRADING, FILL, DETENTION PONDS, BIKE PATHS, PARKING LOTS, UTILITY WORK, FLOOD CONTROL CHANNELS, SIDEWALK OR CURB & GUTTER INSTALLATION/REPLACEMENT, LANDSCAPING, ETC.) MUST BE PRECEDED BY AN APPROVED FLOODPLAIN USE PERMIT, THE APPROPRIATE PERMIT APPLICATION FEES, AND APPROVED PLANS. 5.AN APPROVED FEMA ELEVATION CERTIFICATE COMPLETED BY A LICENSED SURVEYOR OR CIVIL ENGINEER AND A FLOODPROOFING CERTIFICATE SHOWING THAT THE BUILDING IS CONSTRUCTED/FLOODPROOFED TO THE REQUIRED ELEVATION IS REQUIRED POST-CONSTRUCTION PRIOR TO A CERTIFICATE OF OCCUPANCY (CO) BEING ISSUED. PLEASE NOTE: IF ANY PART OF THE BUILDING IS WITHIN THE FLOODPLAIN BOUNDARY, THEN THE ENTIRE STRUCTURE IS CONSIDERED IN THE FLOODPLAIN AND THE ENTIRE BUILDING ENVELOPE MUST MEET THE REQUIREMENTS OF ELEVATING OR FLOODPROOFING TO THE RFPE. 6.OUTSIDE STORAGE OF EQUIPMENT OR FLOATABLE MATERIALS WHETHER PERMANENT OR TEMPORARY IS PROHIBITED IN THE 100-YEAR FLOODPLAIN. ALL FLOATABLE MATERIALS, MUST BE STORED INSIDE A BUILDING, BE ANCHORED PER AN APPROVED ENGINEERED DESIGN, OR BE LOCATED OUTSIDE OF THE 100-YEAR FLOODPLAIN. NO OVERNIGHT PARKING OF VEHICLES IS ALLOWED. 7.AT-RISK POPULATIONS, ESSENTIAL SERVICES, HAZARDOUS MATERIALS, AND GOVERNMENT SERVICES CRITICAL FACILITIES ARE PROHIBITED IN THE 100-YEAR FLOODPLAIN. AT-RISK POPULATION FACILITIES INCLUDE AFTER SCHOOL PROGRAMS/DAY CAMPS FOR K-12, ETC). 8.CONSTRUCTION OF NEW STRUCTURES, HARD SURFACE PATHS, WALKWAYS, DRIVEWAYS, WALLS, AND PARKING AREAS IS PROHIBITED IN THE FLOODWAY UNLESS NO-RISE CONDITIONS ARE MET, PER SECTION 10-45 OF CITY CODE. ANY CONSTRUCTION ACTIVITIES IN THE REGULATORY FLOODWAY MUST ALSO INCLUDE A NO-RISE CERTIFICATION PREPARED BY A PROFESSIONAL ENGINEER LICENSED IN COLORADO. FLOODPLAIN NOTES DESIGN / CONCENTRATION POINT FLOW DIRECTION DP 1 A A 1 2 3 4 5 1 2 3 4 5 PR O J E C T I N F O R M A T I O N SH E E T I N F O R M A T I O N PR O J E C T P H A S E AR C H I T E C T SE A L ISSUE DATE: PROJECT #: CO N S U L T A N T B C D A B C D T - 970.484.0117 F - 970.484.0264 315 East Mountain Ave Suite 100 Fort Collins, CO 80524-2913 © 2015 www.rbbarchitects.com ARCHITECTS REVISIONS: 2204 PR O S P E C T S P O R T S CL U B MA X W E S T I N C . PR O J E C T DE V E L O P M E N T PL A N 12/20/2023 16 0 0 E A S T P R O S P E C T R O A D FO R T C O L L I N S , C O 8 0 5 2 5 DESCRIPTION DATE CIVIL ENGINEERING & CONSULTING UNITED CIVIL Design Group 19 OLD TOWN SQUARE #238 FORT COLLINS, CO 80524 (970) 530-4044 www.unitedcivil.com PR O J . M G R : DR A W I N G N A M E : PA T H : DE S I G N E R : DA T E : TI M E : C5.00 DRAINAGE PLAN POND SUMMARY North Pond South Pond REQUIRED LID VOLUME (CF)260 1,478 PROVIDED LID VOLUME (CF)425 1,570 LID PROVIDED DEPTH 0'-6"1'-0" BOTTOM OF POND ELEVATION 4,900.65 4,896.00 LID WATER SURFACE ELEVATION 4,901.15 4,897.00 TOP OF POND ELEVATION 4,901.50 4,898.00