The URL can be used to link to this page

Home My WebLink About23-30P FedEx Gateway Expansion 100 Constitution Plaza ▪ Hartford, CT 06103 ▪ T (860) 249-2200 ▪ F (860) 249-2400 ▪ www.blcompanies.com 1 Stormwater Management Report For the Proposed: FedEx Gateway Building Expansion Located at: 40 Kennedy Road South Windsor, Connecticut Prepared for Submission to: Town of South Windsor, Connecticut April 26, 2023 Prepared for: FedEx Ground Package Systems, Inc. 1000 FedEx Drive Moon Township, PA 15108 Prepared by: BL Companies 100 Constitution Plaza, 10th Floor Hartford, Connecticut 06103 Phone: (860) 249-2200 Fax: (860) 249-2400 BL Project Number: 2001752.14 100 Constitution Plaza ▪ Hartford, CT 06103 ▪ T (860) 249-2200 ▪ F (860) 249-2400 ▪ www.blcompanies.com 2 Contents Executive Summary ...................................................................................................................................... 3 Existing Site Conditions and Hydrologic Conditions ................................................................................... 3 Developed Site Conditions and Hydrologic Conditions ............................................................................... 4 Summary ....................................................................................................................................................... 5 Appendix A: Location Maps Figure 1: USGS Location Map Figure 2: Aerial Location Map Figure 3: FEMA National Flood Hazard Layer FIRMette Map Appendix B: Drainage Maps ED-1 – Existing Drainage Mapping PD-1 – Proposed Drainage Mapping 100 Constitution Plaza ▪ Hartford, CT 06103 ▪ T (860) 249-2200 ▪ F (860) 249-2400 ▪ www.blcompanies.com 3 Executive Summary This report has been prepared in support of a Site Plan Modification Application for the proposed building expansion located at 40 Kennedy Road in South Windsor, Connecticut. The overall property is a 60.83-acre parcel in the Industrial (I) Zoning District of South Windsor and is currently operating as a FedEx Ground distribution center with associated paved parking, utility connections, stormwater management system, and landscaping. The Project scope will include the modifications to the Gateway Building on site which serves as an accessory use to the overall development. This building is used as the vehicular and pedestrian entrance to the secure facility site. The building expansion will require some minor modifications to the existing site parking areas, site lighting and sidewalk network. There will be minor modifications to the rim elevation of a catch basin as part of this project. The proposed building expansion site modifications will maintain the existing drainage patterns that exist on site today. There will be an overall decrease in impervious cover within the project area. The proposed stormwater management system revisions are designed to be in general compliance with the 2002 State of Connecticut Guidelines for Soil Erosion and Sediment Control, the 2004 Connecticut Stormwater Quality Manual, and Town of South Windsor regulations. Existing Site Conditions and Hydrologic Conditions General Site Information The project work area on the property is currently developed. The site is occupied by buildings, paved parking areas, drive aisles, walkways, and landscaped areas/islands. The proposed site area to be modified typically drains to the catch basins in the center of the parking area adjacent to the Gateway Building. The existing drainage structures eventually discharge into the operational stormwater basin on site. No wetlands or watercourses are located within the surrounding project area limit of disturbance. Per the FEMA National Flood Hazard Layer FIRMette Map, the site resides in FEMA Flood Zone X (unshaded). This is defined as “areas determined to be outside the 0.2% annual chance floodplain. Zone X may have ponding and local drainage problems that don’t warrant a detailed study or designation as base floodplain. A copy of the FEMA FIRMette Map is included in Appendix A for reference. Existing Hydrologic Conditions The following is a brief analysis of the existing project area as shown in the enclosed Existing Drainage Mapping (ED-1) Map, located in Appendix B. This map shows the limits of the proposed 100 Constitution Plaza ▪ Hartford, CT 06103 ▪ T (860) 249-2200 ▪ F (860) 249-2400 ▪ www.blcompanies.com 4 building expansion and site plan modifications. The remainder of the property outside these limits will remain undisturbed as it exists today. Existing Drainage Mapping (ED-1): The existing portion of the site that is located within the proposed project’s construction limits that was analyzed totals 0.55 acres and is approximately 87.3% impervious. There are two catch basins located in the center of the drive aisles adjacent to the Gateway Building that collect and convey stormwater runoff to the existing operational stormwater basin on site. This portion of the site mainly consists of paved parking, building roof area, and concrete walkways. Pervious cover in this area exists within perimeter landscaped areas and parking lot islands. Developed Site Conditions and Hydrologic Conditions General Site Information The project scope will add ±2,500 S.F. to the existing Gateway Building. The proposed project will extend the current Gateway Building to the south of the site and into the existing parking lot. The adjacent parking area will be modified to maintain a landscaped buffer between the buildi ng and the parking area and to maintain full traffic circulation through the parking area. There will be a total reduction to the parking totals on site of 14 passenger car spaces. The total number of ADA parking spaces will be maintained on site. There will be a large landscaped area to the south of the proposed building expansion that will decrease the impervious coverage on site to less than the existing conditions. The existing drainage patterns will remain the same as in the existing condition with all structures eventually draining to the existing stormwater basin. Developed Hydrologic Conditions The intent of the proposed site drainage is to mimic the existing drainage patterns to the maximum extent practical. Impervious area runoff on site within the project area will be clean or unchanged. The remainder of the on-site stormwater management system will not be modified by the proposed building expansion. Catch basins in the project area will be cleaned out upon construction completion. The following is a brief description of the surface cover as shown on the enclosed Proposed Drainage Mapping (PD-1) Map, in Appendix B. Proposed Drainage Area 11 (PDA-11): This portion of the site that is located within the proposed project’s construction limits that was analyzed totals 0.55 acres and is approximately 85.3% impervious. As in the existing conditions, this area will consist of the building roof areas, paved parking areas, and associated landscaped island areas. The proposed drainage system will maintain 100 Constitution Plaza ▪ Hartford, CT 06103 ▪ T (860) 249-2200 ▪ F (860) 249-2400 ▪ www.blcompanies.com 5 the existing hydraulic patterns, with stormwater runoff being captured by on-site catch basins before flowing through the stormwater system as it did previously in existing conditions. Table 1 – Pre and Post Development Drainage Characteristics. Site Development Conditions Total Area (square feet) Impervious Area (square feet) Impervious Cover (%) Existing 23,995 20,945 87.3 Proposed 23,995 20,460 85.3 Difference - - 485 - 2.0% Summary The proposed impervious surfaces on the site have been decreased which will reduce the runoff from the site. The existing stormwater management system will remain in place and continue to operate as originally designed. The remainder of the property will be unchanged and continue to function as it does today. All post development stormwater will be captured by the existing catch basin network and discharged through the stormwater management system as it does today. There will be no impact to the Town drainage system. 100 Constitution Plaza ▪ Hartford, CT 06103 ▪ T (860) 249-2200 ▪ F (860) 249-2400 ▪ www.blcompanies.com APPENDIX A LOCATION MAPS Figure 1: USGS Location Map Figure 2: Aerial Location Map Figure 3: FEMA Federal Insurance Rate Map LAND SURVEYING ENVIRONMENTAL ENGINEERING ARCHITECTURE LAND SURVEYING ENVIRONMENTAL ENGINEERING ARCHITECTURE 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 11/30/2022 at 10:03 AM 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 72°35'19"W 41°51'28"N 72°34'42"W 41°51'1"N Basemap: USGS National Map: Orthoimagery: Data refreshed October, 2020 100 Constitution Plaza ▪ Hartford, CT 06103 ▪ T (860) 249-2200 ▪ F (860) 249-2400 ▪ www.blcompanies.com APPENDIX B DRAINAGE MAPS ED-1 – Existing Drainage Mapping PD-1 – Proposed Drainage Mapping PROPOSED FEDEX GATEWAY BUILDING EXPANSION Drawn Designed 1" = 30' Project No. Scale Date Reviewed 100 Constitution Plaza, 10th Floor (860) 249-2200 Hartford, CT 06103 (860) 249-2400 Fax 2023 BL COMPANIES, INC. THESE DRAWINGS SHALL NOT BE UTILIZED BY ANY PERSON, FIRM OR CORPORATION WITHOUT THE SPECIFIC WRITTEN PERMISSION OF BL COMPANIES.C LAND SURVEYING ENVIRONMENTAL ENGINEERING ARCHITECTURE EXISTING DRAINAGE MAPPING ED-1 SOUTH WINDSOR, CONNECTICUT 40 KENNEDY ROAD Z.T.Z. Z.T.Z.Drawn Designed 2001752.14 1/10/2023 Project No. Scale Date Reviewed 100 Constitution Plaza, 10th Floor (860) 249-2200 Hartford, CT 06103 (860) 249-2400 Fax 2023 BL COMPANIES, INC. THESE DRAWINGS SHALL NOT BE UTILIZED BY ANY PERSON, FIRM OR CORPORATION WITHOUT THE SPECIFIC WRITTEN PERMISSION OF BL COMPANIES.C LAND SURVEYING ENVIRONMENTAL ENGINEERING ARCHITECTURE EXISTING DRAINAGE MAPPING ED-1J.A.B. PROPOSED FEDEX GATEWAY BUILDING EXPANSION Drawn Designed 1" = 30' Project No. Scale Date Reviewed 100 Constitution Plaza, 10th Floor (860) 249-2200 Hartford, CT 06103 (860) 249-2400 Fax 2023 BL COMPANIES, INC. THESE DRAWINGS SHALL NOT BE UTILIZED BY ANY PERSON, FIRM OR CORPORATION WITHOUT THE SPECIFIC WRITTEN PERMISSION OF BL COMPANIES.C LAND SURVEYING ENVIRONMENTAL ENGINEERING ARCHITECTURE SOUTH WINDSOR, CONNECTICUT 40 KENNEDY ROAD Z.T.Z. Z.T.Z.Drawn Designed 2001752.14 1/10/2023 Project No. Scale Date Reviewed 100 Constitution Plaza, 10th Floor (860) 249-2200 Hartford, CT 06103 (860) 249-2400 Fax 2023 BL COMPANIES, INC. THESE DRAWINGS SHALL NOT BE UTILIZED BY ANY PERSON, FIRM OR CORPORATION WITHOUT THE SPECIFIC WRITTEN PERMISSION OF BL COMPANIES.C LAND SURVEYING ENVIRONMENTAL ENGINEERING ARCHITECTURE PROPOSED DRAINAGE MAPPING PD-1J.A.B.