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7 TOWN OF SOUTH WINDSOR INLAND WETLANDS, WATERCOURSES AND CONSERVATION APPLICATION Application # _________________ Date Received ______________________ INSTRUCTIONS 1. Fifteen applications (15) with map and plans (2 copies) shall be submitted together with the fee set forth in the Inland Wetlands, Watercourses and Conservation Regulations, Town of South Windsor. (See Regulations, Section VII – X) 2. The South Windsor Inland Wetlands, Watercourses and Conservation Regulations should be reviewed with respect to the standards and criteria for application Evaluation. (See Regulations, Sections VII – X) 3. The applicant understands that this application is to be considered complete only when all information and documents required by the Agency have been submitted. The applicant shall also complete the state filing form. A. Applicant’s Name: ______________________________________________________________ Address: ________________________________________________________________________ Phone: (home) _____________(work) __________________(email) ________________________ B. Legal owner’s name: _____________________________________________________________ Address _________________________________________________________________________ Phone (home) ______________(work) __________________(email) ________________________ (List additional owners, addresses, and phone numbers on back of application) C. If the applicant is not the owner of the subject property; a letter by the owner(s) authorizing the proposed regulated activity set forth in the application must accompany this form and will be part of the application. D. Project Name (if any) _____________________________________________________________ Project Address _____________________________________________________________ 1. Contact Person (if further information is needed) __________________________________________(work) _________________(fax) ______________ E. The geographical location of the property which is to be affected by the proposed regulated activities including a description of the land in sufficient detail to allow identification of the property on the Inland Wetland and Watercourse Map. Assessor’s map # ________________ Parcel # ____________ Zone _____________ Karen Johnson, AICP, Charter Realty & Development Corp., as Manager 75 Holly Hill Lane, Suite 305, Greenwich, CT 06830 (617) 431-1091 karen@charterrealty.com Evergreen Walk Lifestyle Center, LLC c/o Myles Ostroff, General Manger The Promenade Shops at Evergreen Walk, 501 Evergreen Way, Suite 503, South Windsor, CT 06074 myles@charterrealty.com Proposed Retail Building at the Promenade Shops at Evergreen Walk 801 Evergreen Way, South Windsor, CT Dean Gustafson, All-Points Tech. Corp., P.C. (860) 552-2033 (email)dgustafson@allpointstech.com Map 27, Block 15 Unit 2 Buckland Road Gateway Development (GD) 8 F. Names of all abutting property owners from records in Town Clerk’s office. (use separate sheet if necessary) G. Have you notified all abutting property owners (from records in Town Clerk’s office) by certified letter that an application is pending before the Agency? ** (you are required to supply a copy of the letter with the list of the names of the abutters)** H. Purpose and description of all proposed regulated activity(s) including amount of disturbance in square feet and types of fill and the time element involved: _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________ I. A class A-2 map of the property drawn to 1” = 40’, showing the area to be developed, extent of the wetlands and watercourses affected, topography, existing and proposed activities and names and locations of adjacent property owners must be submitted. J. Amount of regulated area disturbance (within upland review area or regulated buffers) __________________. K. Acreage of wetlands and watercourses in regulated areas to be altered: ______________________________ L. Acreage of wetlands and watercourses to be created: ______________________________ M. Lineal feet of proposed stream alteration: _________________________________________ N. Total land area of project and percentage, which is wetlands: ______________________ _____________________________________________________________________________________ O. Identify all other permits or approvals that have been issued, applied for, or required with respect to the proposed activity set forth in this application. (These may include but not be limited to, local Planning & Zoning, Zoning Board of Appeals, D.E.P., F.E.M.A., D.O.T., The Army Corps of Engineers, and any other State, Local or Federal Permits.) __________________________________________________ refer to attached list The project consists of demolition of two retail buildings and replacement with a 50,000 sf retail building. Redevelopment activities will be confined to existing developed and disturbed areas that will require minimal grading or importation of fill. No direct impact to wetlands or watercourses would occur with the project limited to work in the 80' upland review area, which is currently developed and disturbed. 0.497 acre; disturbances would occur within existing developed and disturbed areas none none; 5,000 sq. ft. wetland enhancment none Unit 2: 48.34341 acres 2,600 sf (0.0597 acre) of wetlands delineated near proposed project Text Amendment, South Windsor PZC; General Plan of Development, South Windsor PZC; Site Plan Review, South Windsor PZC; and, Modification of DOT OSTA Certificate 5 IWA/CC APPLICATION REVIEW (to be filled out by the Applicant): Name _______________________________________________________ Application # _________ I. Fifteen copies of application Plans filed in triplicate. Application fee(s) paid in full. II. The applicant’s name, home and business address, telephone and fax numbers. The owner’s name (if applicant is not the owner of the property), home and business addresses, telephone and fax numbers, and written consent to the proposed activity set forth in the application. If applicant is not the owner, state interest in the land. The geographical location of the property which is to be affected by the proposed activity, including a description of the land in sufficient detail to allow identification of the property on the Inland Wetlands and Water Courses Map included the Map # and Parcel # as shown on the Tax Assessor’s Map. Names of current adjacent property owners from records in the Town Assessor’s office. Proof that all abutting property owners have been notified by certified mail that an application is pending before the Agency. Purpose and description of all proposed regulated activity and the time element involved. Amount and kind of material proposed to be removed, or deposited and/or type of use. Acreage of regulated area to be altered (wetlands, watercourses, or regulated buffer) Acreage of wetlands and watercourses to be created. Lineal feet of proposed stream alteration. Total land area of project and percentage, which are wetlands. Alternatives considered by the applicant and why the proposal to alter the wetlands set forth in the application was chosen. III. Class A-2 map of the area to be developed, 1” = 40’, showing the following: Designate regulated activities; Existing structures and property lines; Locations of existing watercourses and wetlands, as defined in section 2.1bb and 2.1cc and boundaries of regulated areas defined in section 2.1t. Identify the reference for watercourses and/or wetlands boundaries as shown on the map. The identifying numbers or other reference systems used in field delineation shall verify the limits as shown on the plans and shall submit a written report describing the findings. If the property does not contain any watercourses or wetlands this shall be noted on the plans. Charter Realty & Development Corp. 6 Location of 100 year flood lines; Elevations by 2 ft contours; Natural landscape features, woodland and vegetation; existing and proposed tree line. Utilities existing and proposed; Layout of existing and proposed drainage systems; Layout of existing and proposed sanitary sewers or septic systems; Proposed open spaces; Proposed limits of clearing. Proposed areas of change where material is intended to be deposited or removed; Proposed grading or any earth movement anticipated; Percentage of impervious coverage; Disposition of stumps; Test pits on site; Buildable area as defined in section 2.1c; (see waiver provision in section 8.4); Proposed detention basin, if required, sized for 100 year storm; Proposed soil erosion prevention, sediment control and other soil conservation treatments to be taken showing any proposed sediment basin, diversion dikes, indicating the timing of stripping of topsoil, when topsoil shall be stripped, where topsoil shall be stored and for how long, and what method stabilization shall be used, and be in complete compliance with the guidelines expressly set forth in Public Act 83-388, as amended, “An Act Concerning Soil Erosion and Sediment Control” which amends sections 8-2, 8-13d, and 8-25 of the General Statutes of Connecticut. Projected changes in velocity, volume or course of water flow or in the water table and their effects. Soils information – consistent with Natural Resources Conservation Service categories as determined in the field by a qualified soil scientist. Biological and Wetland information – providing a functional analysis of any impacted wetlands, watercourses, an analysis of the probable effect of the proposed activity upon the pland and animal ecosystem. IV. Additional Comments: Date: 4/8/2021 Time: 16:53 User: afedus Style Table: Langan.stb Layout: CS001 Document Code:140222801-0503-CS001-0101 NUMBER DRAWING TITLE LAST REVISEDDATE MAP BLOCK PROPERTY LOCATIONPROPERTY OWNERLOT Filename: \\langan.com\data\NHV\data8\140222801\Project Data\_Discipline\Survey\CAD\Existing\140222801-V-PR0101-Unit 2.dwg Date: 4/6/2021 Time: 14:06 User: aives Style Table: Langan.stb Layout: VL101 © 2 0 2 1 L a n g a n 555 Long Wharf Drive New Haven, CT 06511 T: 203.562.5771 F: 203.789.6142 www.langan.com Langan CT, Inc. Filename: \\langan.com\data\NHV\data8\140222801\Project Data\_Discipline\Survey\CAD\Existing\140222801-V-PR0101-Unit 2.dwg Date: 4/6/2021 Time: 14:06 User: aives Style Table: Langan.stb Layout: VL102 © 2 0 2 1 L a n g a n 555 Long Wharf Drive New Haven, CT 06511 T: 203.562.5771 F: 203.789.6142 www.langan.com Langan CT, Inc. Filename: \\langan.com\data\NHV\data8\140222801\Project Data\_Discipline\Survey\CAD\Existing\140222801-V-PR0101-Unit 2.dwg Date: 4/6/2021 Time: 14:06 User: aives Style Table: Langan.stb Layout: VL103 © 2 0 2 1 L a n g a n 555 Long Wharf Drive New Haven, CT 06511 T: 203.562.5771 F: 203.789.6142 www.langan.com Langan CT, Inc. (NOT SHOWN TO SCALE) ” ” ” ” ” ” ” ” ” ” ” ” Date: 4/8/2021 Time: 16:53 User: afedus Style Table: Langan.stb Layout: CS002 Document Code:140222801-0503-CS002-0101 © La n g a n 20 2 1 555 Long Wharf Drive New Haven, CT 06511 T: 203.562.5771 F: 203.789.6142 www.langan.com Langan CT, Inc. Date: 4/8/2021 Time: 16:54 User: afedus Style Table: Langan.stb Layout: CS101 Document Code:140222801-0503-CS101-0101 © La n g a n 20 2 1 555 Long Wharf Drive New Haven, CT 06511 T: 203.562.5771 F: 203.789.6142 www.langan.com Langan CT, Inc. STOP ASPHALT SECTION SURFACE COURSE - 'X'BINDER COURSE - 'Y'SUBBASE - 'Z' STANDARD DUTY 2 INCHES 2 INCHES 6 INCHES HEAVY DUTY 2 INCHES 3 INCHES 12 INCHES N.T.S. Date: 4/8/2021 Time: 16:54 User: afedus Style Table: Langan.stb Layout: CS501 Document Code:140222801-0503-CS501-0101 © La n g a n 20 2 1 555 Long Wharf Drive New Haven, CT 06511 T: 203.562.5771 F: 203.789.6142 www.langan.com Langan CT, Inc. N.T.S.N.T.S. N.T.S.N.T.S. Date: 4/8/2021 Time: 16:54 User: afedus Style Table: Langan.stb Layout: CS502 Document Code:140222801-0503-CS501-0102 © La n g a n 20 2 1 555 Long Wharf Drive New Haven, CT 06511 T: 203.562.5771 F: 203.789.6142 www.langan.com Langan CT, Inc. Date: 4/8/2021 Time: 16:54 User: afedus Style Table: Langan.stb Layout: CS503 Document Code:140222801-0503-CS501-0103 © La n g a n 20 2 1 555 Long Wharf Drive New Haven, CT 06511 T: 203.562.5771 F: 203.789.6142 www.langan.com Langan CT, Inc. Date: 4/8/2021 Time: 16:55 User: afedus Style Table: Langan.stb Layout: CG101 Document Code:140222801-0503-CG101-0101 © La n g a n 20 2 1 555 Long Wharf Drive New Haven, CT 06511 T: 203.562.5771 F: 203.789.6142 www.langan.com Langan CT, Inc. Date: 4/8/2021 Time: 16:56 User: afedus Style Table: Langan.stb Layout: CG501 Document Code:140222801-0503-CG501-0101 © La n g a n 20 2 1 555 Long Wharf Drive New Haven, CT 06511 T: 203.562.5771 F: 203.789.6142 www.langan.com Langan CT, Inc. Date: 4/8/2021 Time: 16:56 User: afedus Style Table: Langan.stb Layout: CG502 Document Code:140222801-0503-CG501-0102 © La n g a n 20 2 1 555 Long Wharf Drive New Haven, CT 06511 T: 203.562.5771 F: 203.789.6142 www.langan.com Langan CT, Inc. WEST A C C E S S D R I V E TA M A R A C K A V E N U E Date: 4/8/2021 Time: 16:57 User: afedus Style Table: Langan.stb Layout: CU101 Document Code:140222801-0503-CU101-0101 © La n g a n 20 2 1 555 Long Wharf Drive New Haven, CT 06511 T: 203.562.5771 F: 203.789.6142 www.langan.com Langan CT, Inc. Date: 4/8/2021 Time: 16:57 User: afedus Style Table: Langan.stb Layout: CU501 Document Code:140222801-0503-CU501-0101 © La n g a n 20 2 1 555 Long Wharf Drive New Haven, CT 06511 T: 203.562.5771 F: 203.789.6142 www.langan.com Langan CT, Inc. AA SUMP SUMP 6"6"6'-0" 6" 6' - 0 " 6" 6" 6' - 0 " 6" Date: 4/8/2021 Time: 16:57 User: afedus Style Table: Langan.stb Layout: CU502 Document Code:140222801-0503-CU501-0102 © La n g a n 20 2 1 555 Long Wharf Drive New Haven, CT 06511 T: 203.562.5771 F: 203.789.6142 www.langan.com Langan CT, Inc. (S E E M A P R E F . # 7 ) Date: 4/8/2021 Time: 16:59 User: afedus Style Table: Langan.stb Layout: CE101 Document Code:140222801-0503-CE101-0101 © La n g a n 20 2 1 555 Long Wharf Drive New Haven, CT 06511 T: 203.562.5771 F: 203.789.6142 www.langan.com Langan CT, Inc. SECTION NTS PLAN NTS NOTES: 1.ALL MATERIAL TO MEET SPECIFICATIONS. 2. FILTER MEDIA TO MEET APPLICATION REQUIREMENTS. 3. FILTER MEDIA TO BE DISPERSED ON SITE, AS DETERMINED BY ENGINEER. SiltSoxxTM for Sediment Control on Pavement NTS SiltSoxxTM (8" , 12", or 18" TYPICAL) AREA TO BE PROTECTEDWORK AREA WORK AREA AREA TO BE PROTECTED SiltSoxxTM (8", 12", 18" TYPICAL) WATER FLOW Pavement or Impervious Surface Concrete blocks or sand bags sized as needed (10' O.C.) Concrete blocks or sand bags sized as needed (10' O.C.) Date: 4/8/2021 Time: 16:59 User: afedus Style Table: Langan.stb Layout: Layout1 Document Code:140222801-0503-CE501-0101 © La n g a n 20 2 1 555 Long Wharf Drive New Haven, CT 06511 T: 203.562.5771 F: 203.789.6142 www.langan.com Langan CT, Inc. Date: 4/8/2021 Time: 16:59 User: afedus Style Table: Langan.stb Layout: CE502 Document Code:140222801-0503-CE501-0102 © La n g a n 20 2 1 555 Long Wharf Drive New Haven, CT 06511 T: 203.562.5771 F: 203.789.6142 www.langan.com Langan CT, Inc. Date: 4/9/2021 Time: 09:29 User: javeni Style Table: Langan.stb Layout: LP101 Document Code:140222801-0503-LP101-0101 © La n g a n 20 2 1 555 Long Wharf Drive New Haven, CT 06511 T: 203.562.5771 F: 203.789.6142 www.langan.com Langan CT, Inc. ” “ ” “ ” ® . Date: 4/9/2021 Time: 09:25 User: javeni Style Table: Langan.stb Layout: LP501 Document Code:140222801-0503-LP501-0101 © La n g a n 20 2 1 555 Long Wharf Drive New Haven, CT 06511 T: 203.562.5771 F: 203.789.6142 www.langan.com Langan CT, Inc. Date: 4/9/2021 Time: 09:34 User: javeni Style Table: Langan.stb Layout: LP101 Document Code:140222801-0503-LL101-0101 © La n g a n 20 2 1 555 Long Wharf Drive New Haven, CT 06511 T: 203.562.5771 F: 203.789.6142 www.langan.com Langan CT, Inc. - - - - - ----- ----- Date: 4/9/2021 Time: 09:31 User: javeni Style Table: Langan.stb Layout: LL501 Document Code:140222801-0503-LL501-0101 © La n g a n 20 2 1 555 Long Wharf Drive New Haven, CT 06511 T: 203.562.5771 F: 203.789.6142 www.langan.com Langan CT, Inc. Panera Bread Old Navy SITE µ1 inch = 100 feet Planimetric data provided by SBC under contract and is based on an aerial flight performed in spring of 2005. Continuous updates completed with As-built information and State of CT aerial flight in 2016. This map is a graphical representation of property information and is subject to change. The Town of South Windsor and SBC assume no legal responsibility for information depicted on this map and is to be used for planning purposes only. Appl #21-22WEvergreen Walk WETLAND PERMIT APPLICATION ALL-POINTS TECHNOLOGY CORPORATION, P.C. 567 VAUXHALL STREET EXTENSION ∙ SUITE 311 ∙ WATERFORD, CT 06385 ∙ PHONE 860-663-1697 April 13, 2021 Inland Wetlands Agency/Conservation Commission Town of South Windsor 1540 Sullivan Avenue South Windsor, Connecticut 06074 Re: Proposed Retail Building at The Promenade Shops at Evergreen Walk 801 Evergreen Way, South Windsor, CT Dear Commission Members: On behalf of the Applicant, Charter Realty & Development Corp., All-Points Technology Corp., P.C. (“APT”) in coordination with Langan Engineering & Environmental Services (“Langan”) is pleased to submit a Wetland Permit Application to the Town of South Windsor Inland Wetlands Agency/Conservation Commission (“IWA/CC”) for a proposed retail building at The Promenade Shops at Evergreen Walk (the “Project”). The proposed Project is located at 801 Evergreen Way in South Windsor, Connecticut (the “Site” or “Subject Property”) and will consist of redevelopment of two existing retail buildings with a singular retail building. Fifteen (15) copies of the wetland permit application package, consisting of the following materials, are enclosed: • Attachment A: Town of South Windsor Inland Wetlands, Watercourses and Conservation Application, including checklist; • Attachment A: CTDEEP Statewide Inland Wetlands & Watercourses Activity Reporting Form; • Attachment B: Wetland Inspection Report; and, • Attachment C: Figures and Photodocumentation. Also enclosed separately are the following: • Project Site Plans, prepared by Langan dated April 6, 2021 (3 copies separately attached); • Stormwater Management Report, prepared by Langan dated April 8, 2021 (2 copies separately attached); • Direct Abutter Notification and Certificates of Mailing (1 copy separately attached); and, • Application fee check of $260 made out to the Town of South Windsor. 2 | Page The Applicant certifies that: 1. The Site on which the regulated activity is proposed is not located within 500 feet of the boundary of an adjoining municipality; 2. No traffic attributable to the completed project on the Site will use streets within an adjoining municipality to enter or exit the Site; 3. No sewer or water drainage from the project Site will flow through and impact the sewage and drainage system within an adjoining municipality; and, 4. Water run-off from the improved Site will not impact streets or other municipal or private property within an adjoining municipality. The following narrative provides a description of wetland resources located on the Site, the regulated activities that are proposed, evaluation of impacts to the regulated area and mitigation measures. Introduction Planned redevelopment activities include demolition of the two existing retail buildings and associated improvements and construction of a 50,000 square foot retail building within the existing development footprint of the Site. The Site contains a narrow wetland consisting primarily of a drainage swale regulated as an intermittent watercourse along the north Site boundary. The associated 80-foot upland review area currently consists of developed and disturbed areas associated with the existing retail development, including a portion of one of the buildings, paved areas and graded and armored slopes (e.g., retaining wall). No direct impact to the intermittent watercourse would result from the proposed work activities and activities within the upland review area would occur within existing developed and disturbed areas. The location of the Site is depicted on the Site Location Map and the Subject Property’s existing conditions are shown on the Project Area Aerial Photograph, both provided in Attachment C. Please refer to the separately attached project site plans, prepared by Langan dated April 6, 2021, for details of the proposed Project. Wetland Resources Matthew Gustafson, a Connecticut registered Soil Scientist with APT, conducted an inspection of the Site on February 17, 2021 to determine the presence or absence of wetlands and watercourses. The delineation methodology followed is consistent with the Connecticut Inland Wetlands and Watercourses Act (“IWWA”). One wetland (referred to as “Wetland 1”), comprised primarily of a stormwater drainage feature regulated as an intermittent watercourse, was identified along the northern property boundary of the Site. The jurisdictional wetland boundary was marked with pink and blue plastic flagging tape numbered with the following sequence: WF 1-01 to 1-08 and WF 1-20 to 1-40. Details of the wetland delineation are contained in the Wetlands Inspection Report, prepared by APT dated March 18, 2021, and provided in Attachment B. Representative photographs of Wetland 1 are provided in Attachment C. A summary of the delineated wetland resource is provided below. 3 | Page Description Wetland 1 consists of a narrow intermittent watercourse with non-existent/limited bordering vegetated wetlands. This feature is confined between commercial development to the south, and an undeveloped upland field to the north. This resource originates from a discharge point from the Buckland Road closed stormwater system east of the subject property, draining west to a culvert crossing under Evergreen Way, continuing west off the subject property. Wetland 1 is characterized by heavily incised banks, narrow adjacent hardwood forest habitat with an understory dominated by invasive shrubs (e.g., autumn olive, multiflora rose, etc.), and stormwater-driven hydrology. Soil Classification Soil types encountered during the wetland investigation were generally consistent with digitally available soil survey information obtained from the Natural Resources Conservation Service (“NRCS”). Based on available information collected during the wetland investigation the delineated feature is primarily a drainage ditch regulated as an intermittent watercourse. No significant areas of wetland soils are associated with this feature, but small discontinuous wetland soils were identified and classified as Raypol silt loam. Upland soils were examined along the wetland boundary and more distant upland areas during the site investigation. They are dominated by Udorthents-Urban land complex with a small component of Enfield silt loam. Detailed descriptions of wetland and upland soil types are provided below. Wetland Soils: Raypol silt loam consists of very deep, poorly drained soils formed in loamy over sandy and gravelly glacial outwash. They are nearly level to gently sloping soils in shallow drainageways and low-lying positions on terraces and plains. The soils have a water table at or near the surface much of the year. Upland Soils: Enfield silt loam consists of very deep, well drained loamy soils formed in silty mantled glacial outwash. They are nearly level to sloping soils on outwash plains and terraces. Permeability of the Enfield soils is moderate in the surface layer and subsoil and rapid or very rapid in the substratum. The soils formed in a silty mantle over stratified sandy and gravelly fluvial materials derived from a variety of acid rocks. Udorthents-Urban Land Complex is a miscellaneous land type consisting mostly of disturbed soils (cutting, filling & grading) such that the original soil profile can no longer be discerned, buildings, paved roads, and parking lots. Wetland Evaluation There are many methods of evaluating wetlands, all incorporating different parameters to assess these resources. This study uses methodology recommended by the U.S. Army Corps of Engineers (the “Corps”), The Highway Methodology Workbook Supplement, Wetland Functions and Values: A Descriptive Approach issued by the Corps, dated September 1999. This evaluation provides a qualitative approach in which wetland functions can be considered Principal, Secondary, or unlikely to be provided at a significant level. Functions and values can be Principal if they are an important physical component of a wetland ecosystem (function only), and/or are considered of special value to society, from a local, regional, and/or national perspective. The Corps recommends that wetland 4 | Page values and functions be determined through “best professional judgment” based on a qualitative description of the physical attributes of wetlands and the functions and values exhibited. The basis for determination of this qualitative approach relies on over 30 years of field experience and extensive knowledge of other scientific methods used for wetland evaluation purposes. These functions and values can be grouped into four basic categories as follows: Biological Functions Fish and Shellfish Habitat — This function considers the effectiveness of seasonal or permanent waterbodies associated with the wetland in question for fish and shellfish habitat. Wildlife Habitat — This function considers the effectiveness of the wetland to provide habitat for various types and populations of animals typically associated with wetlands and the wetland edge. Production Export (Nutrient) — This function relates to the effectiveness of the wetland to produce food or usable products for humans or other living organisms. Hydrologic Functions Floodflow Alteration (Storage & Desynchronization) — This function considers the effectiveness of the wetland in reducing flood damage by attenuation of floodwaters for prolonged periods following precipitation events. Groundwater Recharge/Discharge — This function considers the potential for a wetland to serve as a groundwater recharge and/or discharge area. Recharge should relate to the potential for the wetland to contribute water to an aquifer. Discharge should relate to the potential for the wetland to serve as an area where groundwater can be discharged to the surface. Water Quality Functions Sediment/Toxicant/Pathogen Retention — This function reduces or prevents degradation of water quality. It relates to the effectiveness of the wetland as a trap for sediments, toxicants, or pathogens. Nutrient Removal/Retention/Transformation — This function relates to the effectiveness of the wetland to prevent adverse effects of excess nutrients entering aquifers or surface waters such as ponds, lakes, streams, rivers, or estuaries. Sediment/Shoreline Stabilization — This function relates to the effectiveness of a wetland to stabilize streambanks and shorelines against erosion. Societal Values Recreation (Consumptive and Non-Consumptive) — This value considers the effectiveness of the wetland and associated watercourses to provide recreational opportunities such as canoeing, boating, fishing, hunting, and other active or passive recreational activities. Consumptive activities consume or diminish the plants, animals, or other resources that are intrinsic to the wetland, whereas non-consumptive activities do not. Educational/Scientific Value — This value considers the effectiveness of the wetland as a site for an “outdoor classroom” or as a location for scientific study or research. 5 | Page Uniqueness/Heritage — This value relates to the effectiveness of the wetland or its associated waterbodies to produce certain special values. Special values may include such things as archaeological sites, unusual aesthetic quality, historical events, or unique plants, animals, or geologic features. Visual Quality/Aesthetics — This value relates to the visual and aesthetic qualities of the wetland. Threatened or Endangered Species Habitat — This value relates to the effectiveness of the wetland or associated waterbodies to support threatened, endangered, or special concern species. The degree to which a wetland provides each of these functions is determined by one or more of the following factors: landscape position, substrate, hydrology, vegetation, history of disturbance, and size. Each wetland may provide one or more of the listed functions at Principal levels. The determining factors that affect the level of function provided by a wetland can often be broken into two categories. The effectiveness of a wetland to provide a specified function is generally dependent on factors within the wetland whereas the opportunity to provide a function is often influenced by the wetland’s position in the landscape and adjacent land uses. For example, a depressed wetland with a restricted outlet may be considered highly effective in trapping sediment due to the long residence time of runoff water passing through the system. If this wetland is located in gently sloping woodland, however, there is no significant source of sediment in the runoff therefore the wetland is considered to have a small opportunity of providing this function. A summary description of functions and values is provided below. Biological Functions The ecological integrity of this wetland has been significantly compromised due to the highly developed surroundings, lack of undisturbed vegetated wetland buffer, poor water quality from stormwater inputs, high level of human activity in and around the wetland, and previous alterations to this system. Therefore, wildlife habitat function is not supported by this wetland at a Principal or Secondary level. No fish population is supported in this wetland due to its ephemeral non-persistent hydrology and the poor water quality (as the primary input is stormwater). In addition, due to the poor water quality and lack of upland buffer, this wetland would not support amphibian and reptile habitat in a significant capacity. No evidence of significant wildlife use was noted within this wetland during the investigations. The wetland is not effective at providing significant production export nor does it support a large diversity of vegetation, wildlife food sources or commercially used products. Hydrologic Functions In terms of hydrologic function, the intermittent watercourse/drainage ditch by design does not provide significant flood storage capacity (i.e., conveyance of stormwater runoff). The groundwater use potential of the wetland is limited due to its narrow form and significant stormwater inputs that could potentially contribute to impaired groundwater quality. 6 | Page Water Quality Although the developed surrounding environment provides an opportunity for this wetland to provide nutrient retention and trapping function, it is not effective in this capacity due to the drainage ditch form and unrestricted outlet. This watercourse feature does provide some sediment/shoreline stabilization function since it is associated with high flow stormwater velocities due to storm events, reflected in the artificial armoring of the banks. Societal Values This wetland provides little to no societal value. Although it is easily accessible, the wetland lacks ecological integrity which detracts from its educational potential. In addition, visual/aesthetic qualities are significantly degraded due to the man-made form (i.e., drainage ditch) and developed setting. The forestry potential is not significant due to the limited mature hardwood trees of high cordwood value. This wetland does provide limited function from an urban wetland quality value perspective. The wetland itself provides little wildlife habitat and has limited ecological integrity and visual/aesthetic quality. Since the wetland is surrounded by development that provides limited habitat for wildlife, its importance could potentially be more significant to this locale. However, no evidence of significant wildlife use was noted within the wetland during APT’s investigations, aside from typical habituated species common to suburban/urban areas. Threatened or Endangered Species Habitat No State-listed Threatened, Endangered or Special Concern species are known to utilize the Subject Property, or its wetlands based on available mapping (December 2020) from the Connecticut Department of Energy & Environmental Protection (“DEEP”) Natural Diversity Data Base (“NDDB”). The nearest NDDB buffer area is located ±1 mile to the west and as such, consultation with DEEP NDDB is not required for this Project. Due to the relatively small forest patch size associated with the intermittent stream/drainage ditch, surrounding development and high level of human activity, the wildlife habitat value for rare species has been significant diminished at the Site and is not considered to be supported at either a Principle or Secondary level. Summary The Principal function of this wetland is associated with the conveyance of stormwater generated by Buckland Road and surrounding developments. Proposed Regulated Activities The following section summarizes development activities classified as “regulated activities” as defined by the IWA/CC’s regulations. The IWA/CC regulates activities in wetland and watercourses and upland areas within 80 feet of wetlands and watercourses, known as an upland review area. Due to the location of wetland resources along the northern Site boundary, the 80-foot upland review area encompasses the northern portion of the Subject Property and the proposed redevelopment activities in that part of the Site are subject jurisdiction by the IWA/CC, resulting in submission of this permit application. 7 | Page The Applicant seeks to demolish the two existing retail buildings and associated improvements and construct of a 50,000 square foot retail building within the existing development footprint of the Site. The Site contains approximately 0.0597 acre (2,600± square feet) of an intermittent watercourse and approximately 0.63 acre (27,430± square feet) of associated 80-foot upland review area. The upland review area currently consists of developed and disturbed areas associated with the existing retail development, including a portion of one of the buildings, paved areas and graded and armored slopes (e.g., retaining wall). No direct impact to the intermittent watercourse, which functions principally as a stormwater drainage feature, would result from the proposed work activities. The program needs of the proposed retail building require some of the redevelopment activities to occur within the 80-foot upland review area; however, all of the regulated activities would occur within existing developed and disturbed areas and would not require removal of trees located within and immediately adjacent to the intermittent watercourse feature. Proposed activities within the upland review area would encompass 0.497± acre (21,650± square feet) and include existing developed and disturbed areas including a portion of a paved drive, the northeast corner of the new retail building and associated landscaping. Stormwater Management The proposed stormwater management system has been designed in general compliance with the Town of South Windsor Design Requirements, the 2002 State of Connecticut Guidelines for Soil Erosion and Sediment Control, and the 2004 Connecticut Stormwater Quality Manual. The proposed stormwater system will effectively manage the quality and quantity of stormwater runoff for the proposed Project, consistent with the approved master plans for Evergreen Walk. The overall impervious coverage has been reduced (approximately 0.5%), the overall peak flow rates have been reduced, and additional water quality measures will be incorporated into the new stormwater system. Water quality Best Management Practices (BMP’s) have been incorporated and include low impact development techniques (e.g., rain gardens and permeable pavers) along with sumped catch basins and three water quality units. The proposed stormwater system, as designed, will effectively manage the stormwater runoff for quality and quantity for the proposed redevelopment. With the proposed stormwater quality improvements in combination with the installation of erosion and sedimentation controls during demolition and construction periods, the Project will result in permanent stabilization and improved stormwater quality that will protect on-Site and nearby wetland resources. For further details of the proposed stormwater management system, please refer to the separately attached Stormwater Management Report for Proposed Grocer at The Promenade Shops at Evergreen Walk, prepared by Langan and dated April 8, 2021. Mitigation Although the proposed Project will not directly impact wetland resources and is limited to activities within the existing developed/disturbed upland review area, there is an opportunity to improve the function of the wetland and immediately adjacent buffer zone to compensate for some of the unavoidable activities in the upland review area. Enhancement to the intermittent steam riparian corridor, consisting of a ±5,000 square foot area, is proposed. This would be accomplished through removal of invasive plants and replanting with native species that will improve functions and values, particularly wildlife habitat function. The existing forested canopy will be supported by the removal of woody invasive plants that currently dominated the understory and planting with a variety of native 8 | Page shrubs. These native shrubs will provide cover, food, and nesting habitat to a variety of small wildlife species, with a focus on supporting avian species. These shrubs will also have a secondary benefit of improving the aesthetics of this wetland feature. Please refer to plan sheets LP101 – Landscape Planting Plan and LP501 – Planting Details for specifics of the enhancement plan, monitoring that will be performed to ensure proper implementation of the plan and post-construction monitoring to document compliance with the mitigation success standards. Impact Analysis The fundamental concept of wetland impact analysis is based on the precept that wetland impacts should first be avoided where possible. Secondly, if practicable alternatives do not exist to avoid wetland impacts, then impacts should be minimized. Thirdly, mitigation should be considered for unavoidable wetland impacts, with consideration given to the loss of wetland functions and values that are important to the local region. As previously discussed, the proposed Project avoids any direct impact to wetlands. Areas of proposed activity within the 80-foot upland review area are proposed to occur within existing degraded/developed areas which include developed pavement and building areas along with regularly maintained landscaping and lawn areas. Upland review areas can serve a number of important functions that support wetlands and watercourses including water quality protection (erosion control and sediment, nutrient, biological and toxics removal), hydrologic event modification and wildlife habitat. However, considering the existing developed and disturbed nature of the upland review area, such functions are not being supported in a significant capacity. Activities within the 80-foot upland review area will actually slightly reduce impervious areas, providing a slight reduction in stormwater runoff. Significant earthwork is not associated with the proposed Project since the majority of work would occur within existing graded, developed, and impervious surfaces. However, due to the proximity of wetland resource, there is the potential for short term wetland impacts during construction. These short-term impacts will be avoided with implementation of a comprehensive soil erosion and sediment control plan, as detailed on the separately attached project site plans (refer to Sheet Nos. CE101, CE501 and CE502). This plan includes perimeter controls of silt fence and/or compost filter sock along with protection of existing catch basins located within the existing parking lot that ultimate discharge to wetlands. Considering the proposed Project avoids any direct wetland impact, is isolated to work within an existing developed/disturbed upland review area, will provide a reduction in impervious surface within the upland review area, and enhancements to the riparian corridor will be provided, no likely adverse impact to wetland resources would result. 9 | Page Conclusion The proposed retail building at The Promenade Shops at Evergreen Walk Project will not directly impact wetland resources. In addition, activities proposed in the 80-foot upland review area will be limited to existing developed and disturbed areas and enhancements will be provided to the riparian corridor to improve wildlife habitat functions (among others). A comprehensive suite of erosion and sedimentation control measures will be implemented during construction to prevent direct and indirect impacts to nearby wetland resources and improvements will be made to the stormwater management system. Therefore, the proposed Project is considered to be adequately protective of the interests contained in the Town of South Windsor Inland Wetlands and Watercourses Regulations and would not result in a likely adverse impact to wetland resources. On behalf of the Application, thank you for your consideration of this application and we look forward to discussing this matter with the IWA/CC at the next available meeting. If you have any questions regarding the above-referenced information, please feel free to contact me by telephone at (860) 552- 2033 or at dgustafson@allpointstech.com. Sincerely, All-Points Technology Corporation, P.C. Dean Gustafson Professional Soil Scientist cc: Karen Johnson, Charter Realty & Development Corp. David Gagnon, Langan Enclosures Attachment A Wetland Application Forms Town of South Windsor Inland Wetlands, Watercourses and Conservation Application, including checklist CTDEEP Statewide Inland Wetlands & Watercourses Activity Reporting Form 7 TOWN OF SOUTH WINDSOR INLAND WETLANDS, WATERCOURSES AND CONSERVATION APPLICATION Application # _________________ Date Received ______________________ INSTRUCTIONS 1. Fifteen applications (15) with map and plans (2 copies) shall be submitted together with the fee set forth in the Inland Wetlands, Watercourses and Conservation Regulations, Town of South Windsor. (See Regulations, Section VII – X) 2. The South Windsor Inland Wetlands, Watercourses and Conservation Regulations should be reviewed with respect to the standards and criteria for application Evaluation. (See Regulations, Sections VII – X) 3. The applicant understands that this application is to be considered complete only when all information and documents required by the Agency have been submitted. The applicant shall also complete the state filing form. A. Applicant’s Name: ______________________________________________________________ Address: ________________________________________________________________________ Phone: (home) _____________(work) __________________(email) ________________________ B. Legal owner’s name: _____________________________________________________________ Address _________________________________________________________________________ Phone (home) ______________(work) __________________(email) ________________________ (List additional owners, addresses, and phone numbers on back of application) C. If the applicant is not the owner of the subject property; a letter by the owner(s) authorizing the proposed regulated activity set forth in the application must accompany this form and will be part of the application. D. Project Name (if any) _____________________________________________________________ Project Address _____________________________________________________________ 1. Contact Person (if further information is needed) __________________________________________(work) _________________(fax) ______________ E. The geographical location of the property which is to be affected by the proposed regulated activities including a description of the land in sufficient detail to allow identification of the property on the Inland Wetland and Watercourse Map. Assessor’s map # ________________ Parcel # ____________ Zone _____________ Karen Johnson, AICP, Charter Realty & Development Corp., as Manager 75 Holly Hill Lane, Suite 305, Greenwich, CT 06830 (617) 431-1091 karen@charterrealty.com Evergreen Walk Lifestyle Center, LLC c/o Myles Ostroff, General Manger The Promenade Shops at Evergreen Walk, 501 Evergreen Way, Suite 503, South Windsor, CT 06074 myles@charterrealty.com Proposed Retail Building at the Promenade Shops at Evergreen Walk 801 Evergreen Way, South Windsor, CT Dean Gustafson, All-Points Tech. Corp., P.C. (860) 552-2033 (email)dgustafson@allpointstech.com Map 27, Block 15 Unit 2 Buckland Road Gateway Development (GD) 8 F. Names of all abutting property owners from records in Town Clerk’s office. (use separate sheet if necessary) G. Have you notified all abutting property owners (from records in Town Clerk’s office) by certified letter that an application is pending before the Agency? ** (you are required to supply a copy of the letter with the list of the names of the abutters)** H. Purpose and description of all proposed regulated activity(s) including amount of disturbance in square feet and types of fill and the time element involved: _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________ I. A class A-2 map of the property drawn to 1” = 40’, showing the area to be developed, extent of the wetlands and watercourses affected, topography, existing and proposed activities and names and locations of adjacent property owners must be submitted. J. Amount of regulated area disturbance (within upland review area or regulated buffers) __________________. K. Acreage of wetlands and watercourses in regulated areas to be altered: ______________________________ L. Acreage of wetlands and watercourses to be created: ______________________________ M. Lineal feet of proposed stream alteration: _________________________________________ N. Total land area of project and percentage, which is wetlands: ______________________ _____________________________________________________________________________________ O. Identify all other permits or approvals that have been issued, applied for, or required with respect to the proposed activity set forth in this application. (These may include but not be limited to, local Planning & Zoning, Zoning Board of Appeals, D.E.P., F.E.M.A., D.O.T., The Army Corps of Engineers, and any other State, Local or Federal Permits.) __________________________________________________ refer to attached list The project consists of demolition of two retail buildings and replacement with a 50,000 sf retail building. Redevelopment activities will be confined to existing developed and disturbed areas that will require minimal grading or importation of fill. No direct impact to wetlands or watercourses would occur with the project limited to work in the 80' upland review area, which is currently developed and disturbed. 0.497 acre; disturbances would occur within existing developed and disturbed areas none none; 5,000 sq. ft. wetland enhancment none Unit 2: 48.34341 acres 2,600 sf (0.0597 acre) of wetlands delineated near proposed project Text Amendment, South Windsor PZC; General Plan of Development, South Windsor PZC; Site Plan Review, South Windsor PZC; and, Modification of DOT OSTA Certificate 5 IWA/CC APPLICATION REVIEW (to be filled out by the Applicant): Name _______________________________________________________ Application # _________ I. Fifteen copies of application Plans filed in triplicate. Application fee(s) paid in full. II. The applicant’s name, home and business address, telephone and fax numbers. The owner’s name (if applicant is not the owner of the property), home and business addresses, telephone and fax numbers, and written consent to the proposed activity set forth in the application. If applicant is not the owner, state interest in the land. The geographical location of the property which is to be affected by the proposed activity, including a description of the land in sufficient detail to allow identification of the property on the Inland Wetlands and Water Courses Map included the Map # and Parcel # as shown on the Tax Assessor’s Map. Names of current adjacent property owners from records in the Town Assessor’s office. Proof that all abutting property owners have been notified by certified mail that an application is pending before the Agency. Purpose and description of all proposed regulated activity and the time element involved. Amount and kind of material proposed to be removed, or deposited and/or type of use. Acreage of regulated area to be altered (wetlands, watercourses, or regulated buffer) Acreage of wetlands and watercourses to be created. Lineal feet of proposed stream alteration. Total land area of project and percentage, which are wetlands. Alternatives considered by the applicant and why the proposal to alter the wetlands set forth in the application was chosen. III. Class A-2 map of the area to be developed, 1” = 40’, showing the following: Designate regulated activities; Existing structures and property lines; Locations of existing watercourses and wetlands, as defined in section 2.1bb and 2.1cc and boundaries of regulated areas defined in section 2.1t. Identify the reference for watercourses and/or wetlands boundaries as shown on the map. The identifying numbers or other reference systems used in field delineation shall verify the limits as shown on the plans and shall submit a written report describing the findings. If the property does not contain any watercourses or wetlands this shall be noted on the plans. Charter Realty & Development Corp. 6 Location of 100 year flood lines; Elevations by 2 ft contours; Natural landscape features, woodland and vegetation; existing and proposed tree line. Utilities existing and proposed; Layout of existing and proposed drainage systems; Layout of existing and proposed sanitary sewers or septic systems; Proposed open spaces; Proposed limits of clearing. Proposed areas of change where material is intended to be deposited or removed; Proposed grading or any earth movement anticipated; Percentage of impervious coverage; Disposition of stumps; Test pits on site; Buildable area as defined in section 2.1c; (see waiver provision in section 8.4); Proposed detention basin, if required, sized for 100 year storm; Proposed soil erosion prevention, sediment control and other soil conservation treatments to be taken showing any proposed sediment basin, diversion dikes, indicating the timing of stripping of topsoil, when topsoil shall be stripped, where topsoil shall be stored and for how long, and what method stabilization shall be used, and be in complete compliance with the guidelines expressly set forth in Public Act 83-388, as amended, “An Act Concerning Soil Erosion and Sediment Control” which amends sections 8-2, 8-13d, and 8-25 of the General Statutes of Connecticut. Projected changes in velocity, volume or course of water flow or in the water table and their effects. Soils information – consistent with Natural Resources Conservation Service categories as determined in the field by a qualified soil scientist. Biological and Wetland information – providing a functional analysis of any impacted wetlands, watercourses, an analysis of the probable effect of the proposed activity upon the pland and animal ecosystem. IV. Additional Comments: rev. 1/2019 e 79 Elm Street • Hartford, CT 06106-5127 www.ct.gov/deep Affirmative Action/Equal Opportunity Employer Statewide Inland Wetlands & Watercourses Activity Reporting Form Please complete and mail this form in accordance with the instructions. If completing by hand - please print and use the pdf version. Incomplete or incomprehensible forms will be mailed back to the municipal inland wetlands agency. PART I: Must Be Completed By The Inland Wetlands Agency 1. DATE ACTION WAS TAKEN: year: Click Here for Year month: Click Here for Month 2. CHOOSE ACTION TAKEN (see instructions for code): Click Here to Choose a Code 3. WAS A PUBLIC HEARING HELD (check one)? yes no 4. NAME OF AGENCY OFFICIAL VERIFYING AND COMPLETING THIS FORM: (type name) (signature) ______________________________________ PART II: To Be Completed By The Inland Wetlands Agency Or The Applicant 5. TOWN IN WHICH THE ACTIVITY IS OCCURRING (type name): South Windsor does this project cross municipal boundaries (check one)? yes no if yes, list the other town(s) in which the activity is occurring (type name(s)): , 6. LOCATION (click on hyperlinks for information): USGS quad map name: Manchester or quad number: 38 subregional drainage basin number: -400401 7. NAME OF APPLICANT, VIOLATOR OR PETITIONER (type name): Charter Realty & Development Corp. 8. NAME & ADDRESS OF ACTIVITY / PROJECT SITE (type information): 801 Evergreen Way briefly describe the action/project/activity (check and type information): temporary permanent description: redevelopment of existing retail with proposed 50,000 sq. ft. retail building 9. ACTIVITY PURPOSE CODE (see instructions for code): D 10. ACTIVITY TYPE CODE(S) (see instructions for codes): 1, 2, 12, 14 11. WETLAND / WATERCOURSE AREA ALTERED (see instructions for explanation, type acres or linear feet as indicated): wetlands: 0.00 acres open water body: 0.00 acres stream: 0.00 linear feet 12. UPLAND AREA ALTERED (type acres as indicated): 0.49 acres 13. AREA OF WETLANDS / WATERCOURSES RESTORED, ENHANCED OR CREATED (type acres as indicated): 0.10 acres DATE RECEIVED: PART III: To Be Completed By The DEEP DATE RETURNED TO DEEP: FORM COMPLETED: YES NO FORM CORRECTED / COMPLETED: YES NO GIS CODE #: ____ ____ ____ ____ ____ ____ ____ ____ ____ For DEEP Use Only Attachment B Wetland Inspection Report ALL-POINTS TECHNOLOGY CORPORATION, P.C. 567 VAUXHALL STREET EXTENSION ∙ SUITE 311 ∙ WATERFORD, CT 06385 ∙ PHONE 860-663-1697 WETLAND INSPECTION March 18, 2021 APT Project No.: CT361820 Prepared For: Langan Engineering and Environmental Services Long Wharf Maritime Center 555 Long Wharf Drive, New Haven, CT 06511 Attn: David Gagnon, P.E. Project Name: Proposed Retail Building at The Promenage Shops at Evergreen Walk Site Address: 801 Evergreen Way, South Windsor, Connecticut Date(s) of Investigation: 2/17/21 Field Conditions: Weather: sunny, mid 20's Soil Moisture: dry to moist Wetland/Watercourse Delineation Methodology *: ☒Connecticut Inland Wetlands and Watercourses Municipal Upland Review Area: Wetlands: 80 feet Watercourses: 80 feet The wetlands inspection was performed by: Matthew Gustafson, Registered Soil Scientist Enclosures: Wetland Delineation Field Form & Wetland Inspection Map This report is provided as a brief summary of findings from APT's wetland investigation of the referenced Study Area that consists of proposed development activities and areas generally within 200 feet.‡ If applicable, APT is available to provide a more comprehensive wetland impact analysis upon receipt of site plans depicting the proposed development activities and surveyed location of identified wetland and watercourse resources. 1 Wetlands and watercourses were delineated in accordance with applicable local, state and federal statutes, regulations and guidance. 2 All established wetlands boundary lines are subject to change until officially adopted by local, state, or federal regulatory agencies. 3 APT has relied upon the accuracy of information provided by Verizon Wireless and its contractors regarding proposed lease area and access road/utility easement locations for identifying wetlands and watercourses within the study area. Attachments Wetland Delineation Field Form Wetland Inspection Map Page 1 of 2 Wetland Delineation Field Form Wetland I.D.: Wetland 1 Flag #’s: WF 1-01 to 1-08 and 1-20 to 1-40 Flag Location Method: Site Sketch ☒ GPS (sub-meter) located ☒ WETLAND HYDROLOGY: NONTIDAL ☒ Intermittently Flooded ☐ Artificially Flooded ☒ Permanently Flooded ☐ Semipermanently Flooded ☐ Seasonally Flooded ☐ Temporarily Flooded ☐ Permanently Saturated ☐ Seasonally Saturated/seepage ☒ Seasonally Saturated/perched ☐ Comments: Wetland 1 is a channelized intermittent watercourse which experiences artificial flooding events heavily influenced by local stormwater discharges off Buckland Road with narrow areas of seasonally saturated seeps contributing to the stream flow. TIDAL ☐ Subtidal ☐ Regularly Flooded ☐ Irregularly Flooded ☐ Irregularly Flooded ☐ Comments: None WETLAND TYPE: SYSTEM: Estuarine ☐ Riverine ☐ Palustrine ☒ Lacustrine ☐ Marine ☐ Comments: None CLASS: Emergent ☒ Scrub-shrub ☒ Forested ☒ Open Water ☐ Disturbed ☒ Wet Meadow ☐ Comments: The majority of Wetland 1 is dominated by edge mature forest cover with transitional areas of scrub/shrub and emergent vegetation resulting from disturbances associated with surrounding development activities. WATERCOURSE TYPE: Perennial ☐ Intermittent ☒ Tidal ☐ Watercourse Name: None Comments: This heavily stormwater influenced watercourse consist of a 3- to 5-foot-wide incised channel with a stone/armored bottom. Banks to this resource are characterized by steep slopes with areas armored with stone gabions and riprap to confine stream flows. Page 2 of 2 Wetland Delineation Field Form (Cont.) SPECIAL AQUATIC HABITAT: Vernal Pool Yes ☐ No ☒ Potential ☐ Other ☐ Vernal Pool Habitat Type: None Comments: None SOILS: Are field identified soils consistent with NRCS mapped soils? Yes ☒ No ☐ DOMINANT PLANTS: Red Maple (Acer rubrum) Eastern Cottonwood (Populus deltoides) Multiflora Rose* (Rosa multiflora) Asiatic Bittersweet* (Celastrus orbiculatus) Silky Dogwood (Cornus amomum) Soft Rush (Juncus effuses) Japanese Knotweed* (Polygonum cuspidatum) Autumn Olive* (Elaeagnus umbellate) * denotes Connecticut Invasive Species Council invasive plant species GENERAL COMMENTS: All-Points Technology Corp., P.C. (“APT”) identified one resource area in the northern portion of 801 Evergreen Way in South Windsor, CT. The subject property is currently developed with two commercial retail buildings, associated paved parking/access areas and related infrastructure. Wetland 1, comprised primarily as a stormwater drainage feature regulated as an intermittent watercourse, generally drains east to west within a narrow corridor along the northern property boundary of the subject property. Wetland 1 consists of a narrow intermittent watercourse with non-existent/limited bordering vegetated wetlands. This feature is confined between commercial development to the south, and an undeveloped upland field to the north. This resource originates from a discharge point from the Buckland Road closed stormwater system east of the subject property, draining west to a culvert crossing under Evergreen Way, continuing west off the subject property. Wetland 1 is characterized by heavily incised banks, narrow adjacent hardwood forest habitat with an understory dominated by invasive shrubs (e.g., autumn olive, multiflora rose, etc.), and stormwater-driven hydrology. APT understands that proposed redevelopment plans will include work activities within the 80-foot upland review area regulated by the Town of South Windsor Inland Wetlands Agency/Conservation Commission. As such, the proposed project would require a permit from this Commission for the regulated activities. #* #* #* #* !H !H Cedar Ave Hem l o c k A v e Bu c k l a n d R d Ev e r g r e e n W a y Ta m a r a c k A v e Wetland 1 WF 1-40 WF 1-20 WF 1-08 WF 1-01 C:\Users\mkope\Dropbox (APT GIS)\APT GIS Team Folder\Projects\Langan\Evergreen Walk\mxd\Evergreen Walk Wetland Inspection Map.mxd Wetland Inspection Map Map Notes:Base Map Source: 2019 CT Aerial Imagery (CTECO)Map Scale: Map Date: February 2021 Legend Project Area #*Wetland Flag Delineated Wetland Boundary 80-Foot Upland Review Area Approximate Wetland Area !H Culvert Approximate Parcel Boundary 150 0 15075Feet 5 Proposed Retail Building 801 Evergreen WaySouth Windsor, Connecticut 1 inch = 150 feet Attachment C Figures and Photodocumentation South Windsor Manchester East Hartford Copyright:© 2013 National Geographic Society, i-cubed C:\Users\mkope\Dropbox (APT GIS)\APT GIS Team Folder\Projects\Langan\Evergreen Walk\mxd\Evergreen Walk USGS Site Location.mxd Site Location Map Map Notes:Base Map Source: USGS 7.5 Minute TopographicQuadrangle Map, Manchester, CT (1992)Map Scale: 1:24,000Map Date: April 2021 Legend Project Area Municipal Boundary Proposed Development801 Evergreen WaySouth Windsor, Connecticut 1,000 0 1,000500Feet 5 ProjectArea Cedar Ave Hem l o c k A v e Ev e r g r e e n W a y Bu c k l a n d R d Ta m a r a c k A v e C:\Users\mkope\Dropbox (APT GIS)\APT GIS Team Folder\Projects\Langan\Evergreen Walk\mxd\Evergreen Walk Aerial Site Location Map.mxd Project Area Aerial Photograph Map Notes:Base Map Source: 2019 CT Aerial Imagery (CTECO)Map Scale: Map Date: April 2021 Legend Project Area Approximate Parcel Boundary 200 0 200100Feet 5 Proposed Development801 Evergreen WaySouth Windsor, Connecticut 1 inch = 200 feet PHOTO DOCUMENTATION 801 Evergreen Way, South Windsor, CT Photos taken on February 17, 2021 Photo 2: View of eastern extent of Wetland 1 looking west at 801 Evergreen Way retail building in background. Photo 1: View of Wetland 1 east of Evergreen Way culvert crossing. 1 PHOTO DOCUMENTATION 801 Evergreen Way, South Windsor, CT Photos taken on February 17, 2021 Photo 4: View of Wetland 1 west of Evergreen Way culvert crossing looking northeast. Photo 3: View of Evergreen Way culvert crossing of Wetland 1, east side of crossing. 2 ALL-POINTS TECHNOLOGY CORPORATION, P.C. 567 VAUXHALL STREET EXTENSION ∙ SUITE 311 ∙ WATERFORD, CT 06385 ∙ PHONE 860-663-1697 WETLAND INSPECTION March 18, 2021 APT Project No.: CT361820 Prepared For: Langan Engineering and Environmental Services Long Wharf Maritime Center 555 Long Wharf Drive, New Haven, CT 06511 Attn: David Gagnon, P.E. Project Name: Proposed Retail Building at The Promenage Shops at Evergreen Walk Site Address: 801 Evergreen Way, South Windsor, Connecticut Date(s) of Investigation: 2/17/21 Field Conditions: Weather: sunny, mid 20's Soil Moisture: dry to moist Wetland/Watercourse Delineation Methodology *: ☒Connecticut Inland Wetlands and Watercourses Municipal Upland Review Area: Wetlands: 80 feet Watercourses: 80 feet The wetlands inspection was performed by: Matthew Gustafson, Registered Soil Scientist Enclosures: Wetland Delineation Field Form & Wetland Inspection Map This report is provided as a brief summary of findings from APT's wetland investigation of the referenced Study Area that consists of proposed development activities and areas generally within 200 feet.‡ If applicable, APT is available to provide a more comprehensive wetland impact analysis upon receipt of site plans depicting the proposed development activities and surveyed location of identified wetland and watercourse resources. 1 Wetlands and watercourses were delineated in accordance with applicable local, state and federal statutes, regulations and guidance. 2 All established wetlands boundary lines are subject to change until officially adopted by local, state, or federal regulatory agencies. 3 APT has relied upon the accuracy of information provided by Verizon Wireless and its contractors regarding proposed lease area and access road/utility easement locations for identifying wetlands and watercourses within the study area. Attachments Wetland Delineation Field Form Wetland Inspection Map Page 1 of 2 Wetland Delineation Field Form Wetland I.D.: Wetland 1 Flag #’s: WF 1-01 to 1-08 and 1-20 to 1-40 Flag Location Method: Site Sketch ☒ GPS (sub-meter) located ☒ WETLAND HYDROLOGY: NONTIDAL ☒ Intermittently Flooded ☐ Artificially Flooded ☒ Permanently Flooded ☐ Semipermanently Flooded ☐ Seasonally Flooded ☐ Temporarily Flooded ☐ Permanently Saturated ☐ Seasonally Saturated/seepage ☒ Seasonally Saturated/perched ☐ Comments: Wetland 1 is a channelized intermittent watercourse which experiences artificial flooding events heavily influenced by local stormwater discharges off Buckland Road with narrow areas of seasonally saturated seeps contributing to the stream flow. TIDAL ☐ Subtidal ☐ Regularly Flooded ☐ Irregularly Flooded ☐ Irregularly Flooded ☐ Comments: None WETLAND TYPE: SYSTEM: Estuarine ☐ Riverine ☐ Palustrine ☒ Lacustrine ☐ Marine ☐ Comments: None CLASS: Emergent ☒ Scrub-shrub ☒ Forested ☒ Open Water ☐ Disturbed ☒ Wet Meadow ☐ Comments: The majority of Wetland 1 is dominated by edge mature forest cover with transitional areas of scrub/shrub and emergent vegetation resulting from disturbances associated with surrounding development activities. WATERCOURSE TYPE: Perennial ☐ Intermittent ☒ Tidal ☐ Watercourse Name: None Comments: This heavily stormwater influenced watercourse consist of a 3- to 5-foot-wide incised channel with a stone/armored bottom. Banks to this resource are characterized by steep slopes with areas armored with stone gabions and riprap to confine stream flows. Page 2 of 2 Wetland Delineation Field Form (Cont.) SPECIAL AQUATIC HABITAT: Vernal Pool Yes ☐ No ☒ Potential ☐ Other ☐ Vernal Pool Habitat Type: None Comments: None SOILS: Are field identified soils consistent with NRCS mapped soils? Yes ☒ No ☐ DOMINANT PLANTS: Red Maple (Acer rubrum) Eastern Cottonwood (Populus deltoides) Multiflora Rose* (Rosa multiflora) Asiatic Bittersweet* (Celastrus orbiculatus) Silky Dogwood (Cornus amomum) Soft Rush (Juncus effuses) Japanese Knotweed* (Polygonum cuspidatum) Autumn Olive* (Elaeagnus umbellate) * denotes Connecticut Invasive Species Council invasive plant species GENERAL COMMENTS: All-Points Technology Corp., P.C. (“APT”) identified one resource area in the northern portion of 801 Evergreen Way in South Windsor, CT. The subject property is currently developed with two commercial retail buildings, associated paved parking/access areas and related infrastructure. Wetland 1, comprised primarily as a stormwater drainage feature regulated as an intermittent watercourse, generally drains east to west within a narrow corridor along the northern property boundary of the subject property. Wetland 1 consists of a narrow intermittent watercourse with non-existent/limited bordering vegetated wetlands. This feature is confined between commercial development to the south, and an undeveloped upland field to the north. This resource originates from a discharge point from the Buckland Road closed stormwater system east of the subject property, draining west to a culvert crossing under Evergreen Way, continuing west off the subject property. Wetland 1 is characterized by heavily incised banks, narrow adjacent hardwood forest habitat with an understory dominated by invasive shrubs (e.g., autumn olive, multiflora rose, etc.), and stormwater-driven hydrology. APT understands that proposed redevelopment plans will include work activities within the 80-foot upland review area regulated by the Town of South Windsor Inland Wetlands Agency/Conservation Commission. As such, the proposed project would require a permit from this Commission for the regulated activities. #* #* #* #* !H !H Cedar Ave Hem l o c k A v e Bu c k l a n d R d Ev e r g r e e n W a y Ta m a r a c k A v e Wetland 1 WF 1-40 WF 1-20 WF 1-08 WF 1-01 C:\Users\mkope\Dropbox (APT GIS)\APT GIS Team Folder\Projects\Langan\Evergreen Walk\mxd\Evergreen Walk Wetland Inspection Map.mxd Wetland Inspection Map Map Notes:Base Map Source: 2019 CT Aerial Imagery (CTECO)Map Scale: Map Date: February 2021 Legend Project Area #*Wetland Flag Delineated Wetland Boundary 80-Foot Upland Review Area Approximate Wetland Area !H Culvert Approximate Parcel Boundary 150 0 15075Feet 5 Proposed Retail Building 801 Evergreen WaySouth Windsor, Connecticut 1 inch = 150 feet STORMWATER MANAGEMENT REPORT for PROPOSED GROCER AT THE PROMENADE SHOPS AT EVERGREEN WALK (UNIT 2) 801 Evergreen Way South Windsor, CT Prepared for: Charter Realty & Development Corp. C/O Karen Johnson 75 Holly Hill Lane, Suite 305 Greenwich, CT 06830 Prepared By: Langan CT, Inc. 555 Long Wharf Drive New Haven, CT 06511 David Gagnon Connecticut P.E. No. 0029766 Timothy S. Onderko Connecticut P.E. No. 25760 April 8, 2021 140222801 TABLE OF CONTENTS Page No. EXECUTIVE SUMMARY 1.0 INTRODUCTION 1.1 General 1.2 Site Location 1.2 Existing Conditions 1.4 Project Description 1.6 FEMA 1.7 Soil Conditions 2.0 STORMWATER MANAGMENT 2.1 Design Criteria 2.2 Design Methodology 2.4 Existing Runoff Discharges 2.5 Proposed Runoff Discharges 3.0 STORMWATER QUALITY 3.1 Stormwater Quality Improvements 3.2 Additional Stormwater Quality Features 4.0 STORMWATER DRAINAGE COLLECTION SYSTEM DESIGN 4.1 Design Criteria 4.2 Design Methodology 4.3 Storm Drainage Collection Summary 5.0 CONCLUSION FIGURES Figure 1 Site Location Map Figure 2 Aerial Map Figure 3 Zoning Map Figure 4 Effective FEMA Firm Map Figure 5 NRCS Soils Map Figure 6 DRA-1 Evergreen Walk Master Plan Development Area DRAWINGS Drawing EX-WS Existing Watershed Map Drawing PR-WS Proposed Watershed Map Drawing DA-CB Drainage Area Map APPENDICES Appendix A Existing Stormwater Discharge Calculations Appendix B Proposed Stormwater Discharge Calculations Appendix C Stormwater Collection System Calculations Appendix D Stormwater Quality Calculations Appendix E NOAA Atlas 14 Rainfall Depths & Intensities Appendix F Operations & Maintenance Plan 801 Evergreen Way April 8, 2021 South Windsor, Connecticut Stormwater Management Report 1 EXECUTIVE SUMMARY Langan prepared this stormwater management report in support of the proposed grocery and retail stores located at 801 Evergreen Way within Unit 2 of the Promenade Shops at Evergreen Walk, located in the town of South Windsor, Connecticut. This site is identified as Map 27, Block 15, Unit 2 by the Town of South Windsor Assessor’s Office and is approximately 7.3± acres of the Evergreen Walk Master Development Plan Area. In the existing condition, two retail buildings with associated parking lots and drive aisles occupy the site. The majority of stormwater is collected by on-site drainage structures. It is conveyed through an existing pipe network in Hemlock Avenue in the westerly direction where it eventually discharges to Detention Basin 4 or a drainage swale that both ultimately discharge to the nearby wetlands. The proposed redevelopment project includes the demolition of the two existing retail buildings and the construction of a ±40,000 square-foot grocer and adjacent inline ±10,000 square-foot retail space. Other associated site improvements including walkways, parking, drive aisles, driveways, site lighting, utility improvements, and drainage improvements. The overall impervious coverage has been reduced (approximately 0.5%), the overall peak flow rates have been reduced, and additional water quality measures have been introduced on site. The proposed stormwater management system has been designed in general compliance with the Town of South Windsor Design Requirements, the 2002 State of Connecticut Guidelines for Soil Erosion and Sediment Control, and the 2004 Connecticut Stormwater Quality Manual. This report demonstrates that the proposed stormwater system will effect ively manage the quality and quantity of stormwater runoff for the proposed development at 801 Evergreen Way, consistent with the approved master plans. A comparative analysis is provided of the calculated total pre- and post-development site runoff conditions, in which the overall peak runoff flow rates leaving the project limits in the 2, 10, 25, and 100-year storm events do not exceed those in the existing condition. In addition, stormwater quality improvements and the installation of erosion and sedimentation controls during demolition and construction periods is specified, as well as long-term stabilization and pollution prevention on the site. Water quality Best Management Practices (BMP’s) have also been incorporated to promote treatment and include sumped catch basins, rain gardens, permeable pavers, a reduction in pervious surfaces, and three water quality units. 801 Evergreen Way April 8, 2021 South Windsor, Connecticut Stormwater Management Report 2 It is the opinion of this office and the findings of this report that the proposed stormwater system, as designed, will effectively manage the stormwater runoff for quality and quantity for the proposed redevelopment. The design in this report is further supported by the “Proposed Grocer at The Promenade Shops at Evergreen Walk” plans prepared by Langan and dated April 6, 2021. 801 Evergreen Way April 8, 2021 South Windsor, Connecticut Stormwater Management Report 3 INTRODUCTION 1.1 General This stormwater management report has been prepared in support of the proposed grocery and retail spaces to be located at 801 Evergreen Way (Unit 2) in the town of South Windsor, Connecticut. The development will include the construction of a ±40,000 square-foot grocer and adjacent inline ±10,000 square-foot retail space along with associated parking, drive aisles, driveways, walkways, a loading dock, landscaped areas, site lighting, utility upgrades, and drainage improvements. This report addresses the engineering design of the stormwater conveyance and management systems for the site. 1.2 Site Location This site is identified as Map 27, Block 15, Unit 2 by the Town of South Windsor Assessor’s Office and is approximately 7.3± acres of the Evergreen Walk Master Development Plan Area. The project limits is bordered by a largely wooded area to the north, wetlands and retail space to the east, a private drive Hemlock Avenue to the south, and Evergreen Crossings Retirement Community to the west. A Costco and fueling station is proposed to be developed to the north of the site on the currently vacant land. 1.3 Existing Conditions The proposed site is currently developed with two existing retail buildings, parking lot, and associated site features. The site generally slopes from east to west with an elevation ±139 at the eastern most part of the site, elevation ±107 in the southwest corner of the site, and existing building elevations of ±130 and ±128. Currently ±2,460 square-feet of wetlands and ±29,765 square-feet of upland review area, inclusive of the wetland area, are present in the northeast corner of the site. The wetlands have been delineated by All Points Technologies Corporation in February 2021 and their findings are presented under a separate cover. 801 Evergreen Way April 8, 2021 South Windsor, Connecticut Stormwater Management Report 4 1.4 Project Description The redevelopment project consists of the demolition of two existing retail spaces and construction of a ±40,000 square-foot grocer and adjacent inline ±10,000 square-foot retail space. Site improvements include parking, drive aisles, driveways, a loading dock, landscaping, walkways, site lighting, utility improvements, and drainage improvements. Because of previous development, no wetland alterations are proposed for the redevelopment of the site, with the exception of intermittent stream and wetland buffer enhancements. Minor regrading and site improvements will take place within the upland review area. These improvements will occur in previously disturbed areas and will generally increase the separation from the wetlands. Under the proposed conditions, small portion of the west, north, and northeast perimeters of the site will continue to sheet flow off site as they do in existing conditions. The stormwater runoff patterns from the interior of the site will generally be maintained. Runoff will continue to be collected by on-site drainage structures where it is conveyed through closed pipe networks before exiting the site through the existing Evergreen Walk stormwater system. New low impact design techniques such as rain gardens will be added to improve water quality treatment prior to discharging to the closed pipe network. 1.5 FEMA According to the Flood Insurance Study of Hartford County, Connecticut conducted by the Federal Emergency Management Agency (FEMA) map number 09003C0383F with an effective date of September 26, 2008 (Figure 4), the site is located within the FEMA Flood Zone X, which is outside of the 100-year floodplain and is considered an area of minimal flood risk. 1.6 Soil Conditions Soils are classified into hydrologic soil groups (HSG) to indicate the minimum rate of infiltration obtained for bare soil after prolonged wetting. The HSGs, which are classified as A, B, C, and D, are one element used to determine runoff curve numbers and analyzing stormwater characteristics on site. 801 Evergreen Way April 8, 2021 South Windsor, Connecticut Stormwater Management Report 5 Group A: Soils having a high infiltration rate (low runoff potential) when thoroughly wet. These consist mainly of deep, well drained to excessively drained sands or gravelly sands. These soils have a high rate of water transmission. Group B: Soils having a moderate infiltration rate when thoroughly wet. These consist chiefly of moderately deep or deep, moderately well drained or well-drained soils that have moderately fine texture to moderately coarse texture. These soils have a moderate rate of water transmission. Group C: Soils having a slow infiltration rate when thoroughly wet. These consist chiefly of soils having a layer that impedes the downward movement of water or soils of moderately fine texture or fine texture. These soils have a slow rate of water transmission. Group D: Soils having a very slow infiltration rate (high runoff potential) when thoroughly wet. These consist chiefly of clays that have a high shrink-swell potential, soils that have a high water table, soils that have a clay pan 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. According to the USDA Natural Resources Conservation Service Web Soil Survey (Figure 5), the site soil type is classified as Tisbury silt loam, 0 to 3 percent; Enfield silt loam, 0 to 3 percent slopes; and Enfield silt loam, 3 to 8 percent slopes. The Web Soil Survey has classified these soils as hydrologic soil groups B and C. Table 1: NRCS Soil Survey Hydrologic Soil Group - Summary by Map Unit- State of Connecticut Map Unit Symbol Map Unit Name Rating 702 A Tisbury silt loam, 0 to 3 percent C 704 A Enfield silt loam, 0 to 3 percent slopes B 704 B Enfield silt loam, 3 to 8 percent slopes B 801 Evergreen Way April 8, 2021 South Windsor, Connecticut Stormwater Management Report 6 All soils within the project site have been classified as hydrologic soil groups B and C. In general, the soils within project site have moderate to slow infiltration rates when thoroughly wet. 1.0 STORMWATER MANAGEMENT 2.1 Design Criteria Proposed peak flow rates at all points of discharge from the site were analyzed to compare proposed discharge rates with the existing condition. The storms analyzed include the following: A 2-year, 24-hour storm consisting of 3.11 inches of rainfall A 10-year, 24-hour storm consisting of 4.91 inches of rainfall A 25-year, 24-hour storm consisting of 6.03 inches of rainfall A 100-year, 24-hour storm consisting of 7.77 inches of rainfall These events are based on NOAA Atlas 14, Volume 10, Version 2 South Windsor, CT. 2.2 Design Methodology The peak runoff discharges for the existing and proposed conditions were analyzed using Soil Conservation Service (SCS) methodology, which outlines procedures for calculating peak rates of runoff resulting from precipitation events, and procedures for developing runoff hydrographs. Values for area, curve number, and time of concentration were calculated for the existing and proposed conditions. The curve number “CN” is a land-sensitive coefficient that dictates the relationship between total rainfall depth and direct storm runoff. The soils within the watershed are divided into hydrologic soil groups (A, B, C, and D) as previously described. The time of concentration, Tc, is defined as the time for runoff to travel from the hydraulically most distant point in the watershed to a point of interest. Values of time of concentration were determined for existing and proposed conditions based on land cover and slope of the flow path, using methods outlined in the SCS methodology. For this study, a 24-hour SCS Type III standard rainfall distribution was used to determine the peak flow rate to all points of discharge from the site. 801 Evergreen Way April 8, 2021 South Windsor, Connecticut Stormwater Management Report 7 2.3 Existing Runoff Discharges (See Appendix A for Calculations) The existing drainage conditions were delineated into four (4) watershed areas: EX-1 through EX-4 (See EX-WS). Watershed EX-1, consisting of 0.35 acres, is comprised of the western edge of the site. It includes steep sloped landscaped and wooded areas and a portion of the western drive aisle, which is approximately 2,200 SF of pavement. Runoff from this watershed sheet flows off site to the west and is either collected in the Tamarack Avenue drainage network or discharged to the wetlands west of the site. Watershed EX-2, consisting of 1.32± acres, is comprised of approximately 3,000± sf of building roof, 47,000± sf of parking lot, and 7,000± landscaped area in the western portion of the site. Runoff from this watershed is collected through drainage structures on site and conveyed through a closed pipe drainage network before exiting the site through an 18-inch RCP pipe that eventually discharges to a drainage swale and ultimately flows into the wetlands west of the site. Watershed EX-3, consisting of 5.46± acres, makes up the majority of the site’s runoff. It is comprised of the majority of the existing building roofs, the main parking area, and the site driveways. Runoff from this watershed is collected through various drainage structures on site and is conveyed through a closed pipe drainage network before exiting the site through a 24-inch RCP pipe that connects to the Evergreen Walk drainage network and eventually discharges to Detention Basin 4 west of the site. Watershed EX-4, consisting 0.16± pervious acres, is comprised of the on-site wetlands in the northeastern corner of the site. Runoff from this watershed sheet flows northeast to the wetlands. 2.4 Proposed Runoff Discharges (See Appendix B for Calculations) The proposed drainage conditions were delineated into four (4) watershed areas: PR-1 through PR-4 (See PR-WS). Watershed PR-1, consisting of 0.39 acres, is comprised of the western edge of the site. It includes steep sloped landscaped and wooded areas and a portion of the western 801 Evergreen Way April 8, 2021 South Windsor, Connecticut Stormwater Management Report 8 drive aisle, which is approximately 1,800 SF of pavement. Runoff from this watershed sheet flows off site to the west and is either collected in the Tamarack Avenue drainage network or discharged to the wetlands west of the site, as it does in existing conditions. Watershed PR-2, consisting of 1.32± acres, is comprised of the western portion of the parking lot. Runoff from this watershed is collected through various drainage structures on site and is conveyed through a closed pipe drainage network. The runoff passes through a proposed water quality unit before exiting the site through an existing 18-inch pipe that connects to a drainage manhole southwest of the site. Runoff eventually discharges to a drainage swale that ultimately flows into wetlands west of the site, as it does in existing conditions. Watershed PR-3, consisting of 5.43± acres, makes up the majority of the site’s runoff. It is comprised of the building roof, the front parking area, and the site driveways. Runoff from this watershed is collected through various drainage structures on site and conveyed through a closed pipe drainage network. The runoff passes through a proposed water quality unit before exiting the site through a 24-inch pipe that connects to the Evergreen Walk drainage network and eventually discharges to Detention Basin 4, as it does in existing conditions. Watershed PR-4, consisting 0.16± pervious acres, is comprised of the on-site wetlands in the northeastern corner of the site. Runoff from this watershed sheet flows northeast to the wetlands as it does in existing conditions. Table 2: Peak Runoff Flow Comparison (CFS) Design Point 2-YEAR 10-YEAR 25-YEAR 100-YEAR Existing Proposed Existing Proposed Existing Proposed Existing Proposed Design Point 1 (Tamarack Ave.) 0.81 0.87 1.49 1.62 1.91 2.09 2.56 2.81 Design Point 2 (Hemlock Ave. 18” RCP) 4.05 3.97 6.51 6.45 8.03 7.98 10.38 10.34 Design Point 3 (Hemlock Ave. 24” RCP) 16.42 16.33 26.67 26.52 32.99 32.81 42.76 42.53 Design Point 4 (Wetlands) 0.34 0.34 0.65 0.65 0.84 0.84 1.14 1.14 Total Site Discharge 21.63 21.51 35.31 35.23 43.76 43.55 56.84 56.81 Note: Because of varying times of concentrations, the total site discharge is not cumulative of the contributing flows. 801 Evergreen Way April 8, 2021 South Windsor, Connecticut Stormwater Management Report 9 The redevelopment project has been designed to the maximum extent practicable to maintain existing drainage patterns. In addition, the proposed development results in a net decrease in the site’s impervious areas by approximately ±1,330 square-feet. Ultimately, the majority of the stormwater on site flows into the wetlands west of the abutting development. By striving to maintain existing drainage patterns to the extent feasible and decreasing the total impervious area, the total site peak flow for all analyzed storms are decreased without any additional stormwater management features. The small increase in the peak flows to Design Point 1, Tamarack Avenue, is expected to have an insignificant impact on the design point, as it is a minimal increase in flow and volume and ultimately connects to the aforementioned wetlands west of the abutting development. Additionally, there is a reduction in discharge rates overall. 2.0 STORMWATER QUALITY 3.1 Stormwater Quality Improvements The stormwater management system has been designed in with the guidance of the Connecticut DEEP Stormwater Quality Manual and the Connecticut DEEP Soil Erosion and Sediment Control Manual. The primary source of water quality improvement comes from the reduction in the sites total impervious area, added landscaped areas, added rain gardens, added water quality units, and modernization of the drainage network. 3.2 Additional Stormwater Quality Features In addition to decreasing the site’s impervious area, the following additional water- quality control measures will be provided: Catch basins with sumps: Catch basins at the site are to be constructed with sumps (minimum 2 feet) to prevent discharge of sediments. Rain gardens: Rain gardens are to be constructed in landscaped islands to facilitate the filtering of collected stormwater. Water Quality Units: Water quality units are to be installed prior to discharge into the existing storm sewer system within Hemlock Avenue. 801 Evergreen Way April 8, 2021 South Windsor, Connecticut Stormwater Management Report 10 Permeable pavers: Permeable pavers are to be installed in the pedestrian only seasonal marketing area, which leads to a net decrease in impervious area for the site. 3.0 STORM DRAINAGE COLLECTION SYSTEM DESIGN (See Appendix C for Calculations) 4.1 Design Criteria The proposed subsurface storm drainage collection system is designed to convey the 10-year design storm with event with one foot of freeboard per the Town of South Windsor requirements. 4.2 Design Methodology The storm drainage system was analyzed using the Rational Method for estimating runoff for a 10-year design storm event. The site was divided into subareas, each contributing runoff to an individual catch basin inlet or roof drain. A value for area, time of concentration, and runoff coefficient was calculated for each contributing subarea. Values of time of concentration were chosen based on land cover and flow path slope from the hydraulically most distant point in the subarea to the appropriate inlet. The average runoff coefficient, which is the ratio of peak runoff rate to the average rainfall rate for the period known as the time of concentration, was chosen using the following values: CONDITION C Grass/Landscaping 0.30 Paved/Impervious/Roof 0.90 Rainfall intensities were taken from the NOAA Atlas 14, Volume 10, Version 2 South Windsor, CT rain gauge data. Storm drainage pipes were then sized based on calculated flows using Manning’s Equation and were verified by solving for the hydraulic grade line. Starting hydraulic grade lines for the pipe networks were set to the calculated maximum water elevations for the 10-year-design storm event within the analyzed drainage network. 4.3 Storm Drainage Collection Summary The runoff from the development will be collected using a conventional roof drains, catch basin, and manhole system. The collection system was designed to convey the 801 Evergreen Way April 8, 2021 South Windsor, Connecticut Stormwater Management Report 11 10-year storm to allow for one foot of free board within the proposed catch basins on- site. 4.0 CONCLUSION The proposed stormwater management system has been designed in general accordance with the town of South Windsor requirements, the 2004 CT DEEP Stormwater Quality Manual, and the 2000 CT DOT Drainage Manual. The system incorporates stormwater quality measures and decreases the overall peak rate of runoff from the project development for all storm events analyzed as compared to the existing conditions. It is the opinion of this office and the findings of this report that the proposed stormwater system, as designed, will effectively manage quality and quantity of stormwater runoff for the proposed development. \\langan.com\data\NHV\data8\140222801\Project Data\_Discipline\Site Civil\Reports\Stormwater\Whole Foods Stormwater Report_recover.doc LIST OF FIGURES Figure 1 Site Location Map Figure 2 Aerial Map Figure 3 Zoning Map Figure 4 Effective FEMA Firm Map Figure 5 NRCS Soils Map LIST OF DRAWINGS EX-WS Existing Watershed Area PR-WS Proposed Watershed Area DA-CB Drainage Area Map FIGURES Project Drawing Title SITE LOCATION MAP Path: \\langan.com\data\NHV\data8\140222801\Project Data\ArcGIS\APRX\140222801- Evergreen Way.aprx Project No. Date Scale Drawn By Figure 2/16/2021 . Notes: 1. The Manchester USGS Quadrangle Map Topographic basemap is provided through Langan’s Esri ArcGIS software licensing and ArcGIS online Copyright: © 2013 National Geographic Society, i-cubed. 1 2,000 0 2,000 SCALE IN FEET SITE 1" = 2,000 feet Legend Site Boundary Langan Engineering and Environmental Services, Inc. © 2 0 2 1 L a n g a n ELB HARTFORD COUNTY CONNECTICUT 140222801801 EVERGREEN WAY SOUTH WINDSOR 888 Boylston Street, Suite 510 Boston, MA 02199 T: 617.824.9100 F: 617.824.9101 www.langan.com Project Drawing Title AERIAL MAP Path: \\langan.com\data\NHV\data8\140222801\Project Data\ArcGIS\APRX\140222801- Evergreen Way.aprx © 2 0 2 1 L a n g a n Project No. Date Scale Drawn By Figure 2/16/2021 ELB . Notes: 1. Imagery provided through Langan's subscription to Nearmap.com. Flown on 07/03/2020. 2. All locations of Site reconnaissance observations are approximate. 2 500 0 500 SCALE IN FEET 1" = 500 feet HARTFORD COUNTY CONNECTICUT 140222801 Legend Site Boundary b 801 EVERGREEN WAY SOUTH WINDSOR Langan Engineering and Environmental Services, Inc. 888 Boylston Street, Suite 510 Boston, MA 02199 T: 617.824.9100 F: 617.824.9101 www.langan.com Project Drawing Title NEARBY PROPERTIES MAP Path: \\langan.com\data\NHV\data8\140222801\Project Data\ArcGIS\APRX\140222801- Evergreen Way.aprx Project No. Date Scale Drawn By Figure 2/16/2021 GD AA-30 RR RC . 3 Legend Site Boundary Zoning Designation AA-30 GD RC RR 500 0 500 SCALE IN FEET b Langan Engineering and Environmental Services, Inc. Notes: 1. Imagery provided through Langan's subscription to Nearmap.com. Flown on 07/03/2020. 2. All locations of Site reconnaissance observations are approximate. 3. Zoning data provided by the Town of South Windsor. 1" = 500 feet © 2 0 2 1 L a n g a n ELB HARTFORD COUNTY CONNECTICUT 140222801801 EVERGREEN WAY SOUTH WINDSOR 888 Boylston Street, Suite 510 Boston, MA 02199 T: 617.824.9100 F: 617.824.9101 www.langan.com Project Drawing Title EFFECTIVE FEMA FIRM Path: \\langan.com\data\NHV\data8\140222801\Project Data\ArcGIS\APRX\140222801- Evergreen Way.aprx Project No. Date Scale Drawn By Figure 2/16/2021 4 Notes: 1. Imagery provided through Langan's subscription to Nearmap.com. Flown on 07/03/2020. 2. All locations of site reconnaissance observations are approximate. 3. Effective FEMA Firm data provided by the Federal Emergency Management Agency. . 1,000 0 1,000 SCALE IN FEET 1" = 1,000 feet Legend Site Boundary FIRM Panels Cross-Sections Limit of Moderate Wave Action Flood Hazard Boundaries Other Boundaries Limit Lines SFHA / Flood Zone Boundary Flood Hazard Zones 1% Annual Chance Flood Hazard Regulatory Floodway Special Floodway Area of Undetermined Flood Hazard 0.2% Annual Chance Flood Hazard Future Conditions 1% Annual Chance Flood Hazard Area with Reduced Risk Due to Levee Langan Engineering and Environmental Services, Inc. © 2 0 2 1 L a n g a n ELB HARTFORD COUNTY CONNECTICUT 140222801 801 EVERGREEN WAY SOUTH WINDSOR 888 Boylston Street, Suite 510 Boston, MA 02199 T: 617.824.9100 F: 617.824.9101 www.langan.com Project Drawing Title NRCS SOILS Path: \\langan.com\data\NHV\data8\140222801\Project Data\ArcGIS\APRX\140222801- Evergreen Way.aprx Date: 2/16/2021 User: eburns Time: 5:31 PM Project No. Date Scale Drawn By Figure 12 701B 702B 701B 702A 701A 702B 29B 28A 28B 28B28B 108704B 704B 704A 704A 66B 28A 53B 67C 66C 9 9 . Notes: 1. Imagery provided through Langan's subscription to Nearmap.com. Flown on 03/07/2020. 2. All locations of Site reconnaissance observations are approximate. 3. Soils data provided by the Natural Resource Conservation Service. 5 400 0 400 SCALE IN FEET © 2 0 2 1 L a n g a n ELB 1" = 400 feet HARTFORD COUNTY CONNECTICUT 140222801801 EVERGREEN WAY SOUTH WINDSOR Langan Engineering and Environmental Services, Inc. 888 Boylston Street, Suite 510 Boston, MA 02199 T: 617.824.9100 F: 617.824.9101 www.langan.com 2/16/2021 Legend Site Boundary Mapunit Symbol,Mapunit Name 108,Saco silt loam 12,Raypol silt loam 28A,Elmridge fine sandy loam, 0 to 3 percent slopes 28B,Elmridge fine sandy loam, 3 to 8 percent slopes 29B,Agawam fine sandy loam, 3 to 8 percent slopes 53B,Wapping very fine sandy loam, 3 to 8 percent slopes 66B,Narragansett silt loam, 2 to 8 percent slopes 66C,Narragansett silt loam, 8 to 15 percent slopes 67C,Narragansett silt loam, 8 to 15 percent slopes, very stony 701A,Ninigret fine sandy loam, 0 to 3 percent slopes 701B,Ninigret fine sandy loam, 3 to 8 percent slopes 702A,Tisbury silt loam, 0 to 3 percent slopes 702B,Tisbury silt loam, 3 to 8 percent slopes 704A,Enfield silt loam, 0 to 3 percent slopes 704B,Enfield silt loam, 3 to 8 percent slopes 9,Scitico, Shaker, and Maybid soils D DETENSION WETLAND MITIGATION AREA ECHN 39,820 sf EXTEN S I O N O F HEMLO C K A V E N U E Recreation below ±15,000 SF L.A.Fitness 45,000 sf Expansion 15,000 sf W A T E R / E C O A R E A D D 1 LEVEL PKG-DECK EXIST./APPROVED 90,250 SF 284,750 SF 229.9 AC. 13.1 AC. 243 AC. Wright Property The Shops - Phase III (88,095 SF u/c) The Shops at Evergreen Walk - BUILDINGS, RETAIL - THE 'BUCKLAND ROAD - THE 'RURAL RESIDENTIAL ZONE' GATEWAY DEVELOPMENT ZONE' LAND AREA WITHIN OVERALL PROPERTY LAND USE TABLE PROPOSED 50,000 SF Site '3' - Lifestyle Retail 95,000 SF TOTAL 350,000 SF375,000 SF 725,000 SF EXISTING 39,820 SF 3,870 SF Office - South I & II ECHN Medical Center The Shops at Evergreen Walk - BUILDINGS, OFFICE PROPOSED 58,800 SF Office - West, A, B, C, D, E, F, G 447,510 SF TOTAL 506,310 SF43,690 SF 550,000 SF EXISTING 30,000 SF 45,000 SF L.A.Fitness Expansion & Site 3 L.A.Fitness at Evergreen Walk - BUILDINGS, RECREATION PROPOSED TOTAL 30,000 SF45,000 SF 75,000 SF EXISTING Hotel - North & South - BUILDINGS, HOTEL PROPOSED TOTAL 250 Rooms 250 Rooms 250 Rooms EXISTING Town Square at Evergreen Walk - BUILDINGS, RESIDENTIAL PROPOSED TOTAL 200 Units 200 Units 200 Units Site '6' - Town Square 205,000 SF ALT ALT EX. C A R T PAT H LOO P B O A R D W A L K BO A R D W A L K WET M E A D O W EV E R G R E E N WA L K WALKING / JOGGING TRAIL WALKING / JOGGING TRAIL 1 LEVEL PKG-DECK 1 LEVEL PKG-DECK1 LEVEL PKG-DECK ± 6,000 SF ± 5, 0 0 0 S F ± 2 0 , 0 0 0 s f R E T A I L / 35 R E S . U N I T S A B O V E ±20 , 0 0 0 s f R E T A I L / 35 R E S . U N I T S A B O V E ±21,000sf RETAIL 20 RES. UNITS ABOVE 100' DEPTH RETAIL, 1 ST. ±56,000 SF RESIDENTIAL. 25 UNITS ± 6,000 SF ±22, 0 0 0 s f R E T A I L 15 R E S . U N I T S A B O V E 100' D E P T H ±12, 0 0 0 s f R E T A I L 15 R E S . U N I T S A B O V E 70' D E P T H ±12,000sf RETAIL 20 RES. UNITS ABOVE 70' DEPTH ± 2 0 , 0 0 0 s f R E T A I L / 3 5 R E S . U N I T S A B O V E ± 5, 0 0 0 S F Retail ±5,000 SF Retail ±10,000 SF Retail ±12,000 SF Retail ±9,000 SF Retail ±19,000 SF Retail ±12,000 SF Retail ±8,000 SF Retail ±13,000 SF Retail ±7,000 SF OFFICE-WEST ±18,200 sf OFFICE-SOUTH II 29,400 SF OFFICE-SOUTH I 29,400 SF OFFICE - A 50,000 SF/ 3 ST. OFFICE - B 40,000 SF/ 3 ST. OFFICE - C 32,500 SF/ 2 ST. OFFICE - D 100,000 sf / 4 st. OFFICE - E 40,000/ 4ST. HOTEL 125 ROOM / 4ST. OFFICE-F 91,810 sf 4 story OFFICE-G 75,000 sf 3 story HOTEL 125 ROOM / 4ST. Retail 6,000 SF Retail 5,000 SF Retail 15,000 SF Retail 24,000 SF EXTENS I O N O F CEDAR A V E N U E BASIN #4 D E T E N S I O N B A S I N # 1 DE T E N S I O N BA S I N # 2 #2a DETENSIONBASIN #7 LM A N : CT B : MS V I E W : UC S : PROJ. No.: DATE: DATUM: SCALE: HORZ.: VERT.: HORZ.: VERT.: Fi l e P a t h : \ \ b l c o m p a n i e s . c o m \ d f s \ p r o j \ J O B S 1 3 \ 1 3 C \ 1 3 C 4 7 1 8 \ R E C O R D \ I N \ 2 0 1 5 - 1 2 - 0 3 m a s t e r p l a n d r a i n a g e a r e a m a p \ P r o p D r a - S t a n d a r d \ S T C D r a i n a g e \ P r o p D r a . d w g , L a y o u t : P R O P D R A T u e , J u n 1 2 , 2 0 1 8 - 1 1 : 4 2 A M U s e r : s l e c l e r c FUSS & O'NEILL Disciplines to Deliver EVERGREEN WALK, LLC PROPOSED WATERSHED AREAS EVERGREEN WALK MASTER DEVELOPMENT PLAN SOUTH WINDSOR CONNECTICUT 2000 481 A30 6/8/2007 DRA-1 1" = 400' WO R L D DRAWINGS WEST A C C E S S D R I V E Date: 4/8/2021 Time: 16:39 User: ibrown Style Table: Langan.stb Layout: Layout1 Document Code:140222801-0503-CG103-0101 © La n g a n 20 2 1 555 Long Wharf Drive New Haven, CT 06511 T: 203.562.5771 F: 203.789.6142 www.langan.com Langan CT, Inc. WEST A C C E S S D R I V E Date: 4/8/2021 Time: 16:46 User: ibrown Style Table: Langan.stb Layout: Layout1 Document Code:140222801-0503-CG104-0101 © La n g a n 20 2 1 555 Long Wharf Drive New Haven, CT 06511 T: 203.562.5771 F: 203.789.6142 www.langan.com Langan CT, Inc. Date: 4/8/2021 Time: 16:51 User: ibrown Style Table: Langan.stb Layout: Layout1 Document Code:140222801-0504-CG104-0101 © La n g a n 20 2 1 555 Long Wharf Drive New Haven, CT 06511 T: 203.562.5771 F: 203.789.6142 www.langan.com Langan CT, Inc. APPENDIX A Existing Stormwater Discharge Calculations Project By HES Date Location Checked JEL Date Circle One: Present Developed Circle One: Tc Tt through subarea NOTES: Space for as many as two segments per flow type can be used for each worksheet. Include a map, schematic, or description of flow segments. Sheet flow (Applicable to Tc Only) Segment ID 1.Surface description (table 3-1) 2. Manning's roughness coeff., n (table 3-1) 3.Flow Length, L (total L < 150 ft)ft 4. Two-yr 24-hr rainfall, P2 in 5. Land slope, s ft/ft Shallow concentrated flow Segment ID 7. Surface description (paved or unpaved) 8. Flow length, L ft 9. Watercourse slope, s ft/ft 10. Average velocity, V (figure 3-1) ft/s Channel flow Segment ID 12. Cross sectional flow area, a ft2 a pw 15. Channel slope, s ft/ft 16. Manning's roughness coeff., n 18. Flow length, L ft 20. Watershed or subarea Tc or Tt (add Tt in steps 6, 11, 19)0.061 hr Use Tc= 5 min =0.0003600 V n 19.Tt =L Compute Tt hr 17. V =1.49 r2/3 s1/2 Compute V ft/s 14. Hydraulic radius, r r =Compute r ft + 13.Wetted perimeter, pw ft =0.00211.Tt =L 3600 V 4.1 Compute Tt hr 0.002 + + 34 0.065 BC Unpaved + + = 0.0596.Tt =Compute Tt hr 0.0590.007(nL)0.8 P2 0.5s0.4 Short Grass Prairie Evergreen Walk 3/12/2021 3.1 0.066 0.15 50 South Windsor, CT 3/12/2021 EX-1 AB Project By HES Date Location Checked JEL Date Circle One: Present Developed Circle One: Tc Tt through subarea NOTES: Space for as many as two segments per flow type can be used for each worksheet. Include a map, schematic, or description of flow segments. Sheet flow (Applicable to Tc Only) Segment ID 1.Surface description (table 3-1) 2. Manning's roughness coeff., n (table 3-1) 3.Flow Length, L (total L < 150 ft)ft 4. Two-yr 24-hr rainfall, P2 in 5. Land slope, s ft/ft Shallow concentrated flow Segment ID 7. Surface description (paved or unpaved) 8. Flow length, L ft 9. Watercourse slope, s ft/ft 10. Average velocity, V (figure 3-1) ft/s Channel flow Segment ID 12. Cross sectional flow area, a ft2 a pw 15. Channel slope, s ft/ft 16. Manning's roughness coeff., n 18. Flow length, L ft 20. Watershed or subarea Tc or Tt (add Tt in steps 6, 11, 19)0.062 hr Use Tc= 5 min =0.0103600 V 5.00n 175 19.Tt =L Compute Tt hr 0.023 0.011 17. V =1.49 r2/3 s1/2 Compute V ft/s 14. Hydraulic radius, r r =Compute r ft 0.010 + DE 13.Wetted perimeter, pw ft =0.03811.Tt =L 3600 V 3.0 2.0 Compute Tt hr 0.011 +0.026 + 125 193 0.022 0.010 BC CD Paved Paved + + = 0.0146.Tt =Compute Tt hr 0.0140.007(nL)0.8 P2 0.5s0.4 Asphalt Evergreen Walk 3/12/2021 3.1 0.012 0.01 50 South Windsor, CT 3/12/2021 EX-2 AB Project By HES Date Location Checked JEL Date Circle One: Present Developed Circle One: Tc Tt through subarea NOTES: Space for as many as two segments per flow type can be used for each worksheet. Include a map, schematic, or description of flow segments. Sheet flow (Applicable to Tc Only) Segment ID 1.Surface description (table 3-1) 2. Manning's roughness coeff., n (table 3-1) 3.Flow Length, L (total L < 150 ft)ft 4. Two-yr 24-hr rainfall, P2 in 5. Land slope, s ft/ft Shallow concentrated flow Segment ID 7. Surface description (paved or unpaved) 8. Flow length, L ft 9. Watercourse slope, s ft/ft 10. Average velocity, V (figure 3-1) ft/s Channel flow Segment ID 12. Cross sectional flow area, a ft2 a pw 15. Channel slope, s ft/ft 16. Manning's roughness coeff., n 18. Flow length, L ft 20. Watershed or subarea Tc or Tt (add Tt in steps 6, 11, 19)0.108 hr Use Tc= 6 min =0.0403600 V 5.00n 721 19.Tt =L Compute Tt hr 0.017 0.011 17. V =1.49 r2/3 s1/2 Compute V ft/s 14. Hydraulic radius, r r =Compute r ft 0.040 + CD 13.Wetted perimeter, pw ft =0.01111.Tt =L 3600 V 2.9 Compute Tt hr 0.011 + + 116 0.032 BC Unpaved + + = 0.0576.Tt =Compute Tt hr 0.0570.007(nL)0.8 P2 0.5s0.4 Short Grass Prairie Evergreen Walk 3/12/2021 3.1 0.072 0.15 50 South Windsor, CT 3/12/2021 EX-3 AB Project By HES Date Location Checked JEL Date Circle One: Present Developed Circle One: Tc Tt through subarea NOTES: Space for as many as two segments per flow type can be used for each worksheet. Include a map, schematic, or description of flow segments. Sheet flow (Applicable to Tc Only) Segment ID 1.Surface description (table 3-1) 2. Manning's roughness coeff., n (table 3-1) 3.Flow Length, L (total L < 150 ft)ft 4. Two-yr 24-hr rainfall, P2 in 5. Land slope, s ft/ft Shallow concentrated flow Segment ID 7. Surface description (paved or unpaved) 8. Flow length, L ft 9. Watercourse slope, s ft/ft 10. Average velocity, V (figure 3-1) ft/s Channel flow Segment ID 12. Cross sectional flow area, a ft2 a pw 15. Channel slope, s ft/ft 16. Manning's roughness coeff., n 18. Flow length, L ft 20. Watershed or subarea Tc or Tt (add Tt in steps 6, 11, 19)0.110 hr Use Tc= 7 min =0.0003600 V n 19.Tt =L Compute Tt hr 17. V =1.49 r2/3 s1/2 Compute V ft/s 14. Hydraulic radius, r r =Compute r ft + 13.Wetted perimeter, pw ft =0.00411.Tt =L 3600 V 3.7 Compute Tt hr 0.004 + + 48 0.053 BC Unpaved + + = 0.1076.Tt =Compute Tt hr 0.1070.007(nL)0.8 P2 0.5s0.4 Short Grass Prairie Evergreen Walk 3/12/2021 3.1 0.015 0.15 50 South Windsor, CT 3/12/2021 EX-4 AB TR-55 Reference Table Abbreviated TR-55 Table 2-2a Runoff Curve Numbers for Urban Areas A B C D Pervious Area Open Space - Lawns, Parks, and Cemeteries 68 79 86 89 Woods and Forest 30 55 70 77 Slectively Cleared Woods and Forest 43 65 76 82 Impervious Area Paved Areas and Roofs 98 98 98 98 Gravel Roads 76 85 89 91 Dirt Roads 72 82 87 89 Developing Urban Areas Newly Graded Pervious Areas 77 86 91 94 Composite Runoff Curve Number Calculation Composite CN = ∑n i=1 CN i ×A i ∑n i =1 Ai n = Number of Distinct Cover Types in the Drainage Area HSG CN Area (ft2)CN × A B 86 13,379 1,150,594 B 98 2,082 204,036 0 0 0 0 0 0 Total 15,461 1,354,630 Composite CN = 88 BY HES DATE 3/12/2021 140222801 CKD JEL DATE 3/12/2021 SHEET 2 OF 6 Fully Developed Urban Areas Drainage Area ID EX-1 Composite Curve Number Calculations Cover Description Curve Numbers for Hydrologic Soil Group (HSG) EVERGREEN WALK LANGAN PROJ. NUMBER: SOUTH WINDSOR, CT Cover Description Newly Graded Pervious Areas Paved Areas and Roofs TR-55 Reference Table Abbreviated TR-55 Table 2-2a Runoff Curve Numbers for Urban Areas A B C D Pervious Area Open Space - Lawns, Parks, and Cemeteries 68 79 86 89 Woods and Forest 30 55 70 77 Slectively Cleared Woods and Forest 43 65 76 82 Impervious Area Paved Areas and Roofs 98 98 98 98 Gravel Roads 76 85 89 91 Dirt Roads 72 82 87 89 Developing Urban Areas Newly Graded Pervious Areas 77 86 91 94 Composite Runoff Curve Number Calculation Composite CN = ∑n i=1 CN i ×A i ∑n i =1 Ai n = Number of Distinct Cover Types in the Drainage Area HSG CN Area (ft2)CN × A B 86 7,171 616,727 B 98 50,664 4,965,081 0 0 0 0 0 0 Total 57,835 5,581,807 Composite CN = 97 BY HES DATE 3/12/2021 140222801 CKD JEL DATE 3/12/2021 SHEET 4 OF 6 Fully Developed Urban Areas Drainage Area ID EX-2 Composite Curve Number Calculations Cover Description Curve Numbers for Hydrologic Soil Group (HSG) EVERGREEN WALK LANGAN PROJ. NUMBER: SOUTH WINDSOR, CT Cover Description Newly Graded Pervious Areas Paved Areas and Roofs TR-55 Reference Table Abbreviated TR-55 Table 2-2a Runoff Curve Numbers for Urban Areas A B C D Pervious Area Open Space - Lawns, Parks, and Cemeteries 68 79 86 89 Woods and Forest 30 55 70 77 Slectively Cleared Woods and Forest 43 65 76 82 Impervious Area Paved Areas and Roofs 98 98 98 98 Gravel Roads 76 85 89 91 Dirt Roads 72 82 87 89 Developing Urban Areas Newly Graded Pervious Areas 77 86 91 94 Composite Runoff Curve Number Calculation Composite CN = ∑n i=1 CN i ×A i ∑n i =1 Ai n = Number of Distinct Cover Types in the Drainage Area HSG CN Area (ft2)CN × A B 86 33,956 2,920,216 C 91 8,939 813,486 B 98 195,305 19,139,890 0 0 0 0 Total 238,200 22,873,592 Composite CN = 96 BY HES DATE 3/12/2021 140222801 CKD JEL DATE 3/12/2021 SHEET 5 OF 6 Fully Developed Urban Areas Drainage Area ID EX-3 Composite Curve Number Calculations Cover Description Curve Numbers for Hydrologic Soil Group (HSG) EVERGREEN WALK LANGAN PROJ. NUMBER: SOUTH WINDSOR, CT Cover Description Newly Graded Pervious Areas Newly Graded Pervious Areas Paved Areas and Roofs TR-55 Reference Table Abbreviated TR-55 Table 2-2a Runoff Curve Numbers for Urban Areas A B C D Pervious Area Open Space - Lawns, Parks, and Cemeteries 68 79 86 89 Woods and Forest 30 55 70 77 Slectively Cleared Woods and Forest 43 65 76 82 Impervious Area Paved Areas and Roofs 98 98 98 98 Gravel Roads 76 85 89 91 Dirt Roads 72 82 87 89 Developing Urban Areas Newly Graded Pervious Areas 77 86 91 94 Composite Runoff Curve Number Calculation Composite CN = ∑n i=1 CN i ×A i ∑n i =1 Ai n = Number of Distinct Cover Types in the Drainage Area HSG CN Area (ft2)CN × A B 86 6,954 598,044 0 0 0 0 0 0 0 0 Total 6,954 598,044 Composite CN = 86 BY HES DATE 3/12/2021 140222801 CKD JEL DATE 3/12/2021 SHEET 6 OF 6 Fully Developed Urban Areas Drainage Area ID EX-4 Composite Curve Number Calculations Cover Description Curve Numbers for Hydrologic Soil Group (HSG) EVERGREEN WALK LANGAN PROJ. NUMBER: SOUTH WINDSOR, CT Cover Description Newly Graded Pervious Areas 1 2 3 4 5 1 Watershed Model Schematic Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Project: Existing Condition.gpw Thursday, 04 / 8 / 2021 Hyd.Origin Description Legend 1 SCS Runoff EX-1 2 SCS Runoff EX-2 3 SCS Runoff EX-3 4 SCS Runoff EX-4 5 Combine Combined Existing Condition Hydrograph Return Period Recap 2 Hyd. Hydrograph Inflow Peak Outflow (cfs)Hydrograph No. type hyd(s)Description (origin) 1-yr 2-yr 3-yr 5-yr 10-yr 25-yr 50-yr 100-yr 1 SCS Runoff ------ ------- 0.811 ------- ------- 1.485 1.906 ------- 2.556 EX-1 2 SCS Runoff ------ ------- 4.053 ------- ------- 6.510 8.029 ------- 10.38 EX-2 3 SCS Runoff ------ ------- 16.42 ------- ------- 26.67 32.99 ------- 42.76 EX-3 4 SCS Runoff ------ ------- 0.341 ------- ------- 0.647 0.840 ------- 1.138 EX-4 5 Combine 1, 2, 3, 4 ------- 21.63 ------- ------- 35.31 43.76 ------- 56.84 Combined Existing Condition Proj. file: Existing Condition.gpw Thursday, 04 / 8 / 2021 Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Hydrograph Summary Report 3 Hyd. Hydrograph Peak Time Time to Hyd. Inflow Maximum Total Hydrograph No. type flow interval Peak volume hyd(s) elevation strge used Description (origin) (cfs) (min) (min) (cuft) (ft) (cuft) 1 SCS Runoff 0.811 1 725 2,511 ------ ------ ------ EX-1 2 SCS Runoff 4.053 1 724 13,674 ------ ------ ------ EX-2 3 SCS Runoff 16.42 1 724 54,377 ------ ------ ------ EX-3 4 SCS Runoff 0.341 1 725 1,052 ------ ------ ------ EX-4 5 Combine 21.63 1 724 71,614 1, 2, 3, 4 ------ ------ Combined Existing Condition Existing Condition.gpw Return Period: 2 Year Thursday, 04 / 8 / 2021 Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Thursday, 04 / 8 / 2021 Hyd. No. 1 EX-1 Hydrograph type = SCS Runoff Peak discharge = 0.811 cfs Storm frequency = 2 yrs Time to peak = 725 min Time interval = 1 min Hyd. volume = 2,511 cuft Drainage area = 0.350 ac Curve number = 88 Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = User Time of conc. (Tc) = 5.00 min Total precip. = 3.11 in Distribution = Type III Storm duration = 24 hrs Shape factor = 484 4 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560 Q (cfs) 0.00 0.00 0.10 0.10 0.20 0.20 0.30 0.30 0.40 0.40 0.50 0.50 0.60 0.60 0.70 0.70 0.80 0.80 0.90 0.90 1.00 1.00 Q (cfs) Time (min) EX-1 Hyd. No. 1 -- 2 Year Hyd No. 1 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Thursday, 04 / 8 / 2021 Hyd. No. 2 EX-2 Hydrograph type = SCS Runoff Peak discharge = 4.053 cfs Storm frequency = 2 yrs Time to peak = 724 min Time interval = 1 min Hyd. volume = 13,674 cuft Drainage area = 1.320 ac Curve number = 97 Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = User Time of conc. (Tc) = 5.00 min Total precip. = 3.11 in Distribution = Type III Storm duration = 24 hrs Shape factor = 484 5 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 Q (cfs) 0.00 0.00 1.00 1.00 2.00 2.00 3.00 3.00 4.00 4.00 5.00 5.00 Q (cfs) Time (min) EX-2 Hyd. No. 2 -- 2 Year Hyd No. 2 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Thursday, 04 / 8 / 2021 Hyd. No. 3 EX-3 Hydrograph type = SCS Runoff Peak discharge = 16.42 cfs Storm frequency = 2 yrs Time to peak = 724 min Time interval = 1 min Hyd. volume = 54,377 cuft Drainage area = 5.460 ac Curve number = 96 Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = User Time of conc. (Tc) = 6.00 min Total precip. = 3.11 in Distribution = Type III Storm duration = 24 hrs Shape factor = 484 6 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 Q (cfs) 0.00 0.00 3.00 3.00 6.00 6.00 9.00 9.00 12.00 12.00 15.00 15.00 18.00 18.00 Q (cfs) Time (min) EX-3 Hyd. No. 3 -- 2 Year Hyd No. 3 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Thursday, 04 / 8 / 2021 Hyd. No. 4 EX-4 Hydrograph type = SCS Runoff Peak discharge = 0.341 cfs Storm frequency = 2 yrs Time to peak = 725 min Time interval = 1 min Hyd. volume = 1,052 cuft Drainage area = 0.160 ac Curve number = 86 Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = User Time of conc. (Tc) = 5.00 min Total precip. = 3.11 in Distribution = Type III Storm duration = 24 hrs Shape factor = 484 7 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560 Q (cfs) 0.00 0.00 0.05 0.05 0.10 0.10 0.15 0.15 0.20 0.20 0.25 0.25 0.30 0.30 0.35 0.35 0.40 0.40 0.45 0.45 0.50 0.50 Q (cfs) Time (min) EX-4 Hyd. No. 4 -- 2 Year Hyd No. 4 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Thursday, 04 / 8 / 2021 Hyd. No. 5 Combined Existing Condition Hydrograph type = Combine Peak discharge = 21.63 cfs Storm frequency = 2 yrs Time to peak = 724 min Time interval = 1 min Hyd. volume = 71,614 cuft Inflow hyds. = 1, 2, 3, 4 Contrib. drain. area = 7.290 ac 8 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 Q (cfs) 0.00 0.00 4.00 4.00 8.00 8.00 12.00 12.00 16.00 16.00 20.00 20.00 24.00 24.00 Q (cfs) Time (min) Combined Existing Condition Hyd. No. 5 -- 2 Year Hyd No. 5 Hyd No. 1 Hyd No. 2 Hyd No. 3 Hyd No. 4 Hydrograph Summary Report 9 Hyd. Hydrograph Peak Time Time to Hyd. Inflow Maximum Total Hydrograph No. type flow interval Peak volume hyd(s) elevation strge used Description (origin) (cfs) (min) (min) (cuft) (ft) (cuft) 1 SCS Runoff 1.485 1 724 4,695 ------ ------ ------ EX-1 2 SCS Runoff 6.510 1 724 22,520 ------ ------ ------ EX-2 3 SCS Runoff 26.67 1 724 90,814 ------ ------ ------ EX-3 4 SCS Runoff 0.647 1 724 2,026 ------ ------ ------ EX-4 5 Combine 35.31 1 724 120,055 1, 2, 3, 4 ------ ------ Combined Existing Condition Existing Condition.gpw Return Period: 10 Year Thursday, 04 / 8 / 2021 Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Thursday, 04 / 8 / 2021 Hyd. No. 1 EX-1 Hydrograph type = SCS Runoff Peak discharge = 1.485 cfs Storm frequency = 10 yrs Time to peak = 724 min Time interval = 1 min Hyd. volume = 4,695 cuft Drainage area = 0.350 ac Curve number = 88 Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = User Time of conc. (Tc) = 5.00 min Total precip. = 4.91 in Distribution = Type III Storm duration = 24 hrs Shape factor = 484 10 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 Q (cfs) 0.00 0.00 1.00 1.00 2.00 2.00 Q (cfs) Time (min) EX-1 Hyd. No. 1 -- 10 Year Hyd No. 1 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Thursday, 04 / 8 / 2021 Hyd. No. 2 EX-2 Hydrograph type = SCS Runoff Peak discharge = 6.510 cfs Storm frequency = 10 yrs Time to peak = 724 min Time interval = 1 min Hyd. volume = 22,520 cuft Drainage area = 1.320 ac Curve number = 97 Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = User Time of conc. (Tc) = 5.00 min Total precip. = 4.91 in Distribution = Type III Storm duration = 24 hrs Shape factor = 484 11 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 Q (cfs) 0.00 0.00 1.00 1.00 2.00 2.00 3.00 3.00 4.00 4.00 5.00 5.00 6.00 6.00 7.00 7.00 Q (cfs) Time (min) EX-2 Hyd. No. 2 -- 10 Year Hyd No. 2 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Thursday, 04 / 8 / 2021 Hyd. No. 3 EX-3 Hydrograph type = SCS Runoff Peak discharge = 26.67 cfs Storm frequency = 10 yrs Time to peak = 724 min Time interval = 1 min Hyd. volume = 90,814 cuft Drainage area = 5.460 ac Curve number = 96 Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = User Time of conc. (Tc) = 6.00 min Total precip. = 4.91 in Distribution = Type III Storm duration = 24 hrs Shape factor = 484 12 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 Q (cfs) 0.00 0.00 4.00 4.00 8.00 8.00 12.00 12.00 16.00 16.00 20.00 20.00 24.00 24.00 28.00 28.00 Q (cfs) Time (min) EX-3 Hyd. No. 3 -- 10 Year Hyd No. 3 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Thursday, 04 / 8 / 2021 Hyd. No. 4 EX-4 Hydrograph type = SCS Runoff Peak discharge = 0.647 cfs Storm frequency = 10 yrs Time to peak = 724 min Time interval = 1 min Hyd. volume = 2,026 cuft Drainage area = 0.160 ac Curve number = 86 Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = User Time of conc. (Tc) = 5.00 min Total precip. = 4.91 in Distribution = Type III Storm duration = 24 hrs Shape factor = 484 13 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560 Q (cfs) 0.00 0.00 0.10 0.10 0.20 0.20 0.30 0.30 0.40 0.40 0.50 0.50 0.60 0.60 0.70 0.70 0.80 0.80 0.90 0.90 1.00 1.00 Q (cfs) Time (min) EX-4 Hyd. No. 4 -- 10 Year Hyd No. 4 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Thursday, 04 / 8 / 2021 Hyd. No. 5 Combined Existing Condition Hydrograph type = Combine Peak discharge = 35.31 cfs Storm frequency = 10 yrs Time to peak = 724 min Time interval = 1 min Hyd. volume = 120,055 cuft Inflow hyds. = 1, 2, 3, 4 Contrib. drain. area = 7.290 ac 14 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 Q (cfs) 0.00 0.00 10.00 10.00 20.00 20.00 30.00 30.00 40.00 40.00 Q (cfs) Time (min) Combined Existing Condition Hyd. No. 5 -- 10 Year Hyd No. 5 Hyd No. 1 Hyd No. 2 Hyd No. 3 Hyd No. 4 Hydrograph Summary Report 15 Hyd. Hydrograph Peak Time Time to Hyd. Inflow Maximum Total Hydrograph No. type flow interval Peak volume hyd(s) elevation strge used Description (origin) (cfs) (min) (min) (cuft) (ft) (cuft) 1 SCS Runoff 1.906 1 724 6,099 ------ ------ ------ EX-1 2 SCS Runoff 8.029 1 724 28,038 ------ ------ ------ EX-2 3 SCS Runoff 32.99 1 724 113,586 ------ ------ ------ EX-3 4 SCS Runoff 0.840 1 724 2,658 ------ ------ ------ EX-4 5 Combine 43.76 1 724 150,381 1, 2, 3, 4 ------ ------ Combined Existing Condition Existing Condition.gpw Return Period: 25 Year Thursday, 04 / 8 / 2021 Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Thursday, 04 / 8 / 2021 Hyd. No. 1 EX-1 Hydrograph type = SCS Runoff Peak discharge = 1.906 cfs Storm frequency = 25 yrs Time to peak = 724 min Time interval = 1 min Hyd. volume = 6,099 cuft Drainage area = 0.350 ac Curve number = 88 Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = User Time of conc. (Tc) = 5.00 min Total precip. = 6.03 in Distribution = Type III Storm duration = 24 hrs Shape factor = 484 16 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 Q (cfs) 0.00 0.00 1.00 1.00 2.00 2.00 Q (cfs) Time (min) EX-1 Hyd. No. 1 -- 25 Year Hyd No. 1 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Thursday, 04 / 8 / 2021 Hyd. No. 2 EX-2 Hydrograph type = SCS Runoff Peak discharge = 8.029 cfs Storm frequency = 25 yrs Time to peak = 724 min Time interval = 1 min Hyd. volume = 28,038 cuft Drainage area = 1.320 ac Curve number = 97 Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = User Time of conc. (Tc) = 5.00 min Total precip. = 6.03 in Distribution = Type III Storm duration = 24 hrs Shape factor = 484 17 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 Q (cfs) 0.00 0.00 2.00 2.00 4.00 4.00 6.00 6.00 8.00 8.00 10.00 10.00 Q (cfs) Time (min) EX-2 Hyd. No. 2 -- 25 Year Hyd No. 2 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Thursday, 04 / 8 / 2021 Hyd. No. 3 EX-3 Hydrograph type = SCS Runoff Peak discharge = 32.99 cfs Storm frequency = 25 yrs Time to peak = 724 min Time interval = 1 min Hyd. volume = 113,586 cuft Drainage area = 5.460 ac Curve number = 96 Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = User Time of conc. (Tc) = 6.00 min Total precip. = 6.03 in Distribution = Type III Storm duration = 24 hrs Shape factor = 484 18 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 Q (cfs) 0.00 0.00 5.00 5.00 10.00 10.00 15.00 15.00 20.00 20.00 25.00 25.00 30.00 30.00 35.00 35.00 Q (cfs) Time (min) EX-3 Hyd. No. 3 -- 25 Year Hyd No. 3 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Thursday, 04 / 8 / 2021 Hyd. No. 4 EX-4 Hydrograph type = SCS Runoff Peak discharge = 0.840 cfs Storm frequency = 25 yrs Time to peak = 724 min Time interval = 1 min Hyd. volume = 2,658 cuft Drainage area = 0.160 ac Curve number = 86 Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = User Time of conc. (Tc) = 5.00 min Total precip. = 6.03 in Distribution = Type III Storm duration = 24 hrs Shape factor = 484 19 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 Q (cfs) 0.00 0.00 0.10 0.10 0.20 0.20 0.30 0.30 0.40 0.40 0.50 0.50 0.60 0.60 0.70 0.70 0.80 0.80 0.90 0.90 1.00 1.00 Q (cfs) Time (min) EX-4 Hyd. No. 4 -- 25 Year Hyd No. 4 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Thursday, 04 / 8 / 2021 Hyd. No. 5 Combined Existing Condition Hydrograph type = Combine Peak discharge = 43.76 cfs Storm frequency = 25 yrs Time to peak = 724 min Time interval = 1 min Hyd. volume = 150,381 cuft Inflow hyds. = 1, 2, 3, 4 Contrib. drain. area = 7.290 ac 20 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 Q (cfs) 0.00 0.00 10.00 10.00 20.00 20.00 30.00 30.00 40.00 40.00 50.00 50.00 Q (cfs) Time (min) Combined Existing Condition Hyd. No. 5 -- 25 Year Hyd No. 5 Hyd No. 1 Hyd No. 2 Hyd No. 3 Hyd No. 4 Hydrograph Summary Report 21 Hyd. Hydrograph Peak Time Time to Hyd. Inflow Maximum Total Hydrograph No. type flow interval Peak volume hyd(s) elevation strge used Description (origin) (cfs) (min) (min) (cuft) (ft) (cuft) 1 SCS Runoff 2.556 1 724 8,311 ------ ------ ------ EX-1 2 SCS Runoff 10.38 1 724 36,619 ------ ------ ------ EX-2 3 SCS Runoff 42.76 1 724 149,031 ------ ------ ------ EX-3 4 SCS Runoff 1.138 1 724 3,659 ------ ------ ------ EX-4 5 Combine 56.84 1 724 197,620 1, 2, 3, 4 ------ ------ Combined Existing Condition Existing Condition.gpw Return Period: 100 Year Thursday, 04 / 8 / 2021 Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Thursday, 04 / 8 / 2021 Hyd. No. 1 EX-1 Hydrograph type = SCS Runoff Peak discharge = 2.556 cfs Storm frequency = 100 yrs Time to peak = 724 min Time interval = 1 min Hyd. volume = 8,311 cuft Drainage area = 0.350 ac Curve number = 88 Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = User Time of conc. (Tc) = 5.00 min Total precip. = 7.77 in Distribution = Type III Storm duration = 24 hrs Shape factor = 484 22 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 Q (cfs) 0.00 0.00 1.00 1.00 2.00 2.00 3.00 3.00 Q (cfs) Time (min) EX-1 Hyd. No. 1 -- 100 Year Hyd No. 1 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Thursday, 04 / 8 / 2021 Hyd. No. 2 EX-2 Hydrograph type = SCS Runoff Peak discharge = 10.38 cfs Storm frequency = 100 yrs Time to peak = 724 min Time interval = 1 min Hyd. volume = 36,619 cuft Drainage area = 1.320 ac Curve number = 97 Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = User Time of conc. (Tc) = 5.00 min Total precip. = 7.77 in Distribution = Type III Storm duration = 24 hrs Shape factor = 484 23 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 Q (cfs) 0.00 0.00 2.00 2.00 4.00 4.00 6.00 6.00 8.00 8.00 10.00 10.00 12.00 12.00 Q (cfs) Time (min) EX-2 Hyd. No. 2 -- 100 Year Hyd No. 2 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Thursday, 04 / 8 / 2021 Hyd. No. 3 EX-3 Hydrograph type = SCS Runoff Peak discharge = 42.76 cfs Storm frequency = 100 yrs Time to peak = 724 min Time interval = 1 min Hyd. volume = 149,031 cuft Drainage area = 5.460 ac Curve number = 96 Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = User Time of conc. (Tc) = 6.00 min Total precip. = 7.77 in Distribution = Type III Storm duration = 24 hrs Shape factor = 484 24 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 Q (cfs) 0.00 0.00 10.00 10.00 20.00 20.00 30.00 30.00 40.00 40.00 50.00 50.00 Q (cfs) Time (min) EX-3 Hyd. No. 3 -- 100 Year Hyd No. 3 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Thursday, 04 / 8 / 2021 Hyd. No. 4 EX-4 Hydrograph type = SCS Runoff Peak discharge = 1.138 cfs Storm frequency = 100 yrs Time to peak = 724 min Time interval = 1 min Hyd. volume = 3,659 cuft Drainage area = 0.160 ac Curve number = 86 Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = User Time of conc. (Tc) = 5.00 min Total precip. = 7.77 in Distribution = Type III Storm duration = 24 hrs Shape factor = 484 25 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 Q (cfs) 0.00 0.00 1.00 1.00 2.00 2.00 Q (cfs) Time (min) EX-4 Hyd. No. 4 -- 100 Year Hyd No. 4 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Thursday, 04 / 8 / 2021 Hyd. No. 5 Combined Existing Condition Hydrograph type = Combine Peak discharge = 56.84 cfs Storm frequency = 100 yrs Time to peak = 724 min Time interval = 1 min Hyd. volume = 197,620 cuft Inflow hyds. = 1, 2, 3, 4 Contrib. drain. area = 7.290 ac 26 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 Q (cfs) 0.00 0.00 10.00 10.00 20.00 20.00 30.00 30.00 40.00 40.00 50.00 50.00 60.00 60.00 Q (cfs) Time (min) Combined Existing Condition Hyd. No. 5 -- 100 Year Hyd No. 5 Hyd No. 1 Hyd No. 2 Hyd No. 3 Hyd No. 4 APPENDIX B Proposed Stormwater Discharge Calculations Project By IJAB Date Location Checked DTG Date Circle One: Present Developed Circle One: Tc Tt through subarea NOTES: Space for as many as two segments per flow type can be used for each worksheet. Include a map, schematic, or description of flow segments. Sheet flow (Applicable to Tc Only) Segment ID 1.Surface description (table 3-1) 2. Manning's roughness coeff., n (table 3-1) 3.Flow Length, L (total L < 150 ft)ft 4. Two-yr 24-hr rainfall, P2 in 5. Land slope, s ft/ft Shallow concentrated flow Segment ID 7. Surface description (paved or unpaved) 8. Flow length, L ft 9. Watercourse slope, s ft/ft 10. Average velocity, V (figure 3-1) ft/s Channel flow Segment ID 12. Cross sectional flow area, a ft2 a pw 15. Channel slope, s ft/ft 16. Manning's roughness coeff., n 18. Flow length, L ft 20. Watershed or subarea Tc or Tt (add Tt in steps 6, 11, 19)0.059 hr Use Tc= 5 min South Windsor, CT 4/7/2021 PR-1 AB Short Grass Prairie Evergreen Walk 4/7/2021 3.1 0.069 0.15 50 + + = 0.0586.Tt =Compute Tt hr 0.0580.007(nL)0.8 P2 0.5s0.4 20 0.065 BC Unpaved =0.00111.Tt =L 3600 V 4.1 Compute Tt hr 0.001 + + 13.Wetted perimeter, pw ft 19.Tt =L Compute Tt hr 17. V =1.49 r2/3 s1/2 Compute V ft/s 14. Hydraulic radius, r r =Compute r ft + =0.0003600 V n Project By IJAB Date Location Checked DTG Date Circle One: Present Developed Circle One: Tc Tt through subarea NOTES: Space for as many as two segments per flow type can be used for each worksheet. Include a map, schematic, or description of flow segments. Sheet flow (Applicable to Tc Only) Segment ID 1.Surface description (table 3-1) 2. Manning's roughness coeff., n (table 3-1) 3.Flow Length, L (total L < 150 ft)ft 4. Two-yr 24-hr rainfall, P2 in 5. Land slope, s ft/ft Shallow concentrated flow Segment ID 7. Surface description (paved or unpaved) 8. Flow length, L ft 9. Watercourse slope, s ft/ft 10. Average velocity, V (figure 3-1) ft/s Channel flow Segment ID 12. Cross sectional flow area, a ft2 a pw 15. Channel slope, s ft/ft 16. Manning's roughness coeff., n 18. Flow length, L ft 20. Watershed or subarea Tc or Tt (add Tt in steps 6, 11, 19)0.059 hr Use Tc= 5 min South Windsor, CT 4/7/2021 EX-2 AB Asphalt Evergreen Walk 4/7/2021 3.1 0.017 0.01 50 + + = 0.0136.Tt =Compute Tt hr 0.0130.007(nL)0.8 P2 0.5s0.4 74 103 0.017 0.016 BC CD Paved Paved =0.01911.Tt =L 3600 V 2.7 2.6 Compute Tt hr 0.008 +0.011 + DE 13.Wetted perimeter, pw ft 19.Tt =L Compute Tt hr 0.010 0.011 17. V =1.49 r2/3 s1/2 Compute V ft/s 14. Hydraulic radius, r r =Compute r ft 0.027 + =0.0273600 V 5.00n 494 Project By IJAB Date Location Checked DTG Date Circle One: Present Developed Circle One: Tc Tt through subarea NOTES: Space for as many as two segments per flow type can be used for each worksheet. Include a map, schematic, or description of flow segments. Sheet flow (Applicable to Tc Only) Segment ID 1.Surface description (table 3-1) 2. Manning's roughness coeff., n (table 3-1) 3.Flow Length, L (total L < 150 ft)ft 4. Two-yr 24-hr rainfall, P2 in 5. Land slope, s ft/ft Shallow concentrated flow Segment ID 7. Surface description (paved or unpaved) 8. Flow length, L ft 9. Watercourse slope, s ft/ft 10. Average velocity, V (figure 3-1) ft/s Channel flow Segment ID 12. Cross sectional flow area, a ft2 a pw 15. Channel slope, s ft/ft 16. Manning's roughness coeff., n 18. Flow length, L ft 20. Watershed or subarea Tc or Tt (add Tt in steps 6, 11, 19)0.062 hr Use Tc= 5 min South Windsor, CT 4/7/2021 PR-3 AB BC Short Grass Prairie Asphalt Evergreen Walk 4/7/2021 3.1 3.1 0.130 0.020 0.15 0.01 8 36 + 0.008 + = 0.0196.Tt =Compute Tt hr 0.0100.007(nL)0.8 P2 0.5s0.4 Unpaved =0.00011.Tt =L 3600 V Compute Tt hr + + CD 13.Wetted perimeter, pw ft 19.Tt =L Compute Tt hr 0.010 0.011 17. V =1.49 r2/3 s1/2 Compute V ft/s 14. Hydraulic radius, r r =Compute r ft 0.043 + =0.0433600 V 5.00n 769 Project By IJAB Date Location Checked DTG Date Circle One: Present Developed Circle One: Tc Tt through subarea NOTES: Space for as many as two segments per flow type can be used for each worksheet. Include a map, schematic, or description of flow segments. Sheet flow (Applicable to Tc Only) Segment ID 1.Surface description (table 3-1) 2. Manning's roughness coeff., n (table 3-1) 3.Flow Length, L (total L < 150 ft)ft 4. Two-yr 24-hr rainfall, P2 in 5. Land slope, s ft/ft Shallow concentrated flow Segment ID 7. Surface description (paved or unpaved) 8. Flow length, L ft 9. Watercourse slope, s ft/ft 10. Average velocity, V (figure 3-1) ft/s Channel flow Segment ID 12. Cross sectional flow area, a ft2 a pw 15. Channel slope, s ft/ft 16. Manning's roughness coeff., n 18. Flow length, L ft 20. Watershed or subarea Tc or Tt (add Tt in steps 6, 11, 19)0.110 hr Use Tc= 7 min South Windsor, CT 4/7/2021 PR-4 AB Short Grass Prairie Evergreen Walk 4/7/2021 3.1 0.015 0.15 50 + + = 0.1076.Tt =Compute Tt hr 0.1070.007(nL)0.8 P2 0.5s0.4 48 0.053 BC Unpaved =0.00411.Tt =L 3600 V 3.7 Compute Tt hr 0.004 + + 13.Wetted perimeter, pw ft 19.Tt =L Compute Tt hr 17. V =1.49 r2/3 s1/2 Compute V ft/s 14. Hydraulic radius, r r =Compute r ft + =0.0003600 V n TR-55 Reference Table Abbreviated TR-55 Table 2-2a Runoff Curve Numbers for Urban Areas A B C D Pervious Area Open Space - Lawns, Parks, and Cemeteries 68 79 86 89 Woods and Forest 30 55 70 77 Slectively Cleared Woods and Forest 43 65 76 82 Impervious Area Paved Areas and Roofs 98 98 98 98 Gravel Roads 76 85 89 91 Dirt Roads 72 82 87 89 Developing Urban Areas Newly Graded Pervious Areas 77 86 91 94 Composite Runoff Curve Number Calculation Composite CN = ∑n i=1 CN i ×A i ∑n i =1 Ai n = Number of Distinct Cover Types in the Drainage Area HSG CN Area (ft2)CN × A B 86 15,324 1,317,864 B 98 1,793 175,714 0 0 0 0 0 0 Total 17,117 1,493,578 Composite CN = 87 BY HES DATE 3/12/2021 140222801 CKD JEL DATE 3/12/2021 SHEET 3 OF 6 Fully Developed Urban Areas Drainage Area ID PR-1 Composite Curve Number Calculations Cover Description Curve Numbers for Hydrologic Soil Group (HSG) EVERGREEN WALK LANGAN PROJ. NUMBER: SOUTH WINDSOR, CT Cover Description Newly Graded Pervious Areas Paved Areas and Roofs TR-55 Reference Table Abbreviated TR-55 Table 2-2a Runoff Curve Numbers for Urban Areas A B C D Pervious Area Open Space - Lawns, Parks, and Cemeteries 68 79 86 89 Woods and Forest 30 55 70 77 Slectively Cleared Woods and Forest 43 65 76 82 Impervious Area Paved Areas and Roofs 98 98 98 98 Gravel Roads 76 85 89 91 Dirt Roads 72 82 87 89 Developing Urban Areas Newly Graded Pervious Areas 77 86 91 94 Composite Runoff Curve Number Calculation Composite CN = ∑n i=1 CN i ×A i ∑n i =1 Ai n = Number of Distinct Cover Types in the Drainage Area HSG CN Area (ft2)CN × A B 86 7,677 660,222 B 98 49,975 4,897,550 0 0 0 0 0 0 Total 57,652 5,557,772 Composite CN = 96 BY HES DATE 3/12/2021 140222801 CKD JEL DATE 3/12/2021 SHEET 4 OF 6 Fully Developed Urban Areas Drainage Area ID PR-2 Composite Curve Number Calculations Cover Description Curve Numbers for Hydrologic Soil Group (HSG) EVERGREEN WALK LANGAN PROJ. NUMBER: SOUTH WINDSOR, CT Cover Description Newly Graded Pervious Areas Paved Areas and Roofs TR-55 Reference Table Abbreviated TR-55 Table 2-2a Runoff Curve Numbers for Urban Areas A B C D Pervious Area Open Space - Lawns, Parks, and Cemeteries 68 79 86 89 Woods and Forest 30 55 70 77 Slectively Cleared Woods and Forest 43 65 76 82 Impervious Area Paved Areas and Roofs 98 98 98 98 Gravel Roads 76 85 89 91 Dirt Roads 72 82 87 89 Developing Urban Areas Newly Graded Pervious Areas 77 86 91 94 Composite Runoff Curve Number Calculation Composite CN = ∑n i=1 CN i ×A i ∑n i =1 Ai n = Number of Distinct Cover Types in the Drainage Area HSG CN Area (ft2)CN × A B 86 32,959 2,834,474 C 91 4,937 449,267 B 98 195,896 19,197,808 B 85 3,000 255,000 0 0 Total 236,792 22,736,549 Composite CN = 96 BY HES DATE 3/12/2021 140222801 CKD JEL DATE 3/12/2021 SHEET 5 OF 6 Fully Developed Urban Areas Drainage Area ID PR-3 Composite Curve Number Calculations Cover Description Curve Numbers for Hydrologic Soil Group (HSG) EVERGREEN WALK LANGAN PROJ. NUMBER: SOUTH WINDSOR, CT Cover Description Newly Graded Pervious Areas Newly Graded Pervious Areas Paved Areas and Roofs Gravel Roads TR-55 Reference Table Abbreviated TR-55 Table 2-2a Runoff Curve Numbers for Urban Areas A B C D Pervious Area Open Space - Lawns, Parks, and Cemeteries 68 79 86 89 Woods and Forest 30 55 70 77 Slectively Cleared Woods and Forest 43 65 76 82 Impervious Area Paved Areas and Roofs 98 98 98 98 Gravel Roads 76 85 89 91 Dirt Roads 72 82 87 89 Developing Urban Areas Newly Graded Pervious Areas 77 86 91 94 Composite Runoff Curve Number Calculation Composite CN = ∑n i=1 CN i ×A i ∑n i =1 Ai n = Number of Distinct Cover Types in the Drainage Area HSG CN Area (ft2)CN × A B 86 6,954 598,044 0 0 0 0 0 0 0 0 Total 6,954 598,044 Composite CN = 86 BY HES DATE 3/12/2021 140222801 CKD JEL DATE 3/12/2021 SHEET 6 OF 6 EVERGREEN WALK LANGAN PROJ. NUMBER: SOUTH WINDSOR, CT Cover Description Newly Graded Pervious Areas Drainage Area ID PR-4 Composite Curve Number Calculations Cover Description Curve Numbers for Hydrologic Soil Group (HSG) Fully Developed Urban Areas 1 2 3 4 5 1 Watershed Model Schematic Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Project: Proposed Condition.gpw Wednesday, 04 / 7 / 2021 Hyd.Origin Description Legend 1 SCS Runoff PR-1 2 SCS Runoff PR-2 3 SCS Runoff PR-3 4 SCS Runoff PR-4 5 Combine Combined - Proposed Condition Hydrograph Return Period Recap 2 Hyd. Hydrograph Inflow Peak Outflow (cfs)Hydrograph No. type hyd(s)Description (origin) 1-yr 2-yr 3-yr 5-yr 10-yr 25-yr 50-yr 100-yr 1 SCS Runoff ------ ------- 0.868 ------- ------- 1.616 2.086 ------- 2.812 PR-1 2 SCS Runoff ------ ------- 3.971 ------- ------- 6.447 7.975 ------- 10.34 PR-2 3 SCS Runoff ------ ------- 16.33 ------- ------- 26.52 32.81 ------- 42.53 PR-3 4 SCS Runoff ------ ------- 0.341 ------- ------- 0.647 0.840 ------- 1.138 PR-4 5 Combine 1, 2, 3, 4 ------- 21.51 ------- ------- 35.23 43.71 ------- 56.81 Combined - Proposed Condition Proj. file: Proposed Condition.gpw Wednesday, 04 / 7 / 2021 Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Hydrograph Summary Report 3 Hyd. Hydrograph Peak Time Time to Hyd. Inflow Maximum Total Hydrograph No. type flow interval Peak volume hyd(s) elevation strge used Description (origin) (cfs) (min) (min) (cuft) (ft) (cuft) 1 SCS Runoff 0.868 1 725 2,680 ------ ------ ------ PR-1 2 SCS Runoff 3.971 1 724 13,146 ------ ------ ------ PR-2 3 SCS Runoff 16.33 1 724 54,078 ------ ------ ------ PR-3 4 SCS Runoff 0.341 1 725 1,052 ------ ------ ------ PR-4 5 Combine 21.51 1 724 70,956 1, 2, 3, 4 ------ ------ Combined - Proposed Condition Proposed Condition.gpw Return Period: 2 Year Wednesday, 04 / 7 / 2021 Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Wednesday, 04 / 7 / 2021 Hyd. No. 1 PR-1 Hydrograph type = SCS Runoff Peak discharge = 0.868 cfs Storm frequency = 2 yrs Time to peak = 12.08 hrs Time interval = 1 min Hyd. volume = 2,680 cuft Drainage area = 0.390 ac Curve number = 87 Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = User Time of conc. (Tc) = 5.00 min Total precip. = 3.11 in Distribution = Type III Storm duration = 24 hrs Shape factor = 484 4 0 2 4 6 8 10 12 14 16 18 20 22 24 26 Q (cfs) 0.00 0.00 0.10 0.10 0.20 0.20 0.30 0.30 0.40 0.40 0.50 0.50 0.60 0.60 0.70 0.70 0.80 0.80 0.90 0.90 1.00 1.00 Q (cfs) Time (hrs) PR-1 Hyd. No. 1 -- 2 Year Hyd No. 1 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Wednesday, 04 / 7 / 2021 Hyd. No. 2 PR-2 Hydrograph type = SCS Runoff Peak discharge = 3.971 cfs Storm frequency = 2 yrs Time to peak = 12.07 hrs Time interval = 1 min Hyd. volume = 13,146 cuft Drainage area = 1.320 ac Curve number = 96 Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = User Time of conc. (Tc) = 5.00 min Total precip. = 3.11 in Distribution = Type III Storm duration = 24 hrs Shape factor = 484 5 0 2 4 6 8 10 12 14 16 18 20 22 24 Q (cfs) 0.00 0.00 1.00 1.00 2.00 2.00 3.00 3.00 4.00 4.00 Q (cfs) Time (hrs) PR-2 Hyd. No. 2 -- 2 Year Hyd No. 2 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Wednesday, 04 / 7 / 2021 Hyd. No. 3 PR-3 Hydrograph type = SCS Runoff Peak discharge = 16.33 cfs Storm frequency = 2 yrs Time to peak = 12.07 hrs Time interval = 1 min Hyd. volume = 54,078 cuft Drainage area = 5.430 ac Curve number = 96 Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = User Time of conc. (Tc) = 5.00 min Total precip. = 3.11 in Distribution = Type III Storm duration = 24 hrs Shape factor = 484 6 0 2 4 6 8 10 12 14 16 18 20 22 24 Q (cfs) 0.00 0.00 3.00 3.00 6.00 6.00 9.00 9.00 12.00 12.00 15.00 15.00 18.00 18.00 Q (cfs) Time (hrs) PR-3 Hyd. No. 3 -- 2 Year Hyd No. 3 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Wednesday, 04 / 7 / 2021 Hyd. No. 4 PR-4 Hydrograph type = SCS Runoff Peak discharge = 0.341 cfs Storm frequency = 2 yrs Time to peak = 12.08 hrs Time interval = 1 min Hyd. volume = 1,052 cuft Drainage area = 0.160 ac Curve number = 86 Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = User Time of conc. (Tc) = 5.00 min Total precip. = 3.11 in Distribution = Type III Storm duration = 24 hrs Shape factor = 484 7 0 2 4 6 8 10 12 14 16 18 20 22 24 26 Q (cfs) 0.00 0.00 0.05 0.05 0.10 0.10 0.15 0.15 0.20 0.20 0.25 0.25 0.30 0.30 0.35 0.35 0.40 0.40 0.45 0.45 0.50 0.50 Q (cfs) Time (hrs) PR-4 Hyd. No. 4 -- 2 Year Hyd No. 4 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Wednesday, 04 / 7 / 2021 Hyd. No. 5 Combined - Proposed Condition Hydrograph type = Combine Peak discharge = 21.51 cfs Storm frequency = 2 yrs Time to peak = 12.07 hrs Time interval = 1 min Hyd. volume = 70,956 cuft Inflow hyds. = 1, 2, 3, 4 Contrib. drain. area = 7.300 ac 8 0 2 4 6 8 10 12 14 16 18 20 22 24 Q (cfs) 0.00 0.00 4.00 4.00 8.00 8.00 12.00 12.00 16.00 16.00 20.00 20.00 24.00 24.00 Q (cfs) Time (hrs) Combined - Proposed Condition Hyd. No. 5 -- 2 Year Hyd No. 5 Hyd No. 1 Hyd No. 2 Hyd No. 3 Hyd No. 4 Hydrograph Summary Report 9 Hyd. Hydrograph Peak Time Time to Hyd. Inflow Maximum Total Hydrograph No. type flow interval Peak volume hyd(s) elevation strge used Description (origin) (cfs) (min) (min) (cuft) (ft) (cuft) 1 SCS Runoff 1.616 1 724 5,084 ------ ------ ------ PR-1 2 SCS Runoff 6.447 1 724 21,955 ------ ------ ------ PR-2 3 SCS Runoff 26.52 1 724 90,314 ------ ------ ------ PR-3 4 SCS Runoff 0.647 1 724 2,026 ------ ------ ------ PR-4 5 Combine 35.23 1 724 119,380 1, 2, 3, 4 ------ ------ Combined - Proposed Condition Proposed Condition.gpw Return Period: 10 Year Wednesday, 04 / 7 / 2021 Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Wednesday, 04 / 7 / 2021 Hyd. No. 1 PR-1 Hydrograph type = SCS Runoff Peak discharge = 1.616 cfs Storm frequency = 10 yrs Time to peak = 12.07 hrs Time interval = 1 min Hyd. volume = 5,084 cuft Drainage area = 0.390 ac Curve number = 87 Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = User Time of conc. (Tc) = 5.00 min Total precip. = 4.91 in Distribution = Type III Storm duration = 24 hrs Shape factor = 484 10 0 2 4 6 8 10 12 14 16 18 20 22 24 Q (cfs) 0.00 0.00 1.00 1.00 2.00 2.00 Q (cfs) Time (hrs) PR-1 Hyd. No. 1 -- 10 Year Hyd No. 1 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Wednesday, 04 / 7 / 2021 Hyd. No. 2 PR-2 Hydrograph type = SCS Runoff Peak discharge = 6.447 cfs Storm frequency = 10 yrs Time to peak = 12.07 hrs Time interval = 1 min Hyd. volume = 21,955 cuft Drainage area = 1.320 ac Curve number = 96 Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = User Time of conc. (Tc) = 5.00 min Total precip. = 4.91 in Distribution = Type III Storm duration = 24 hrs Shape factor = 484 11 0 2 4 6 8 10 12 14 16 18 20 22 24 Q (cfs) 0.00 0.00 1.00 1.00 2.00 2.00 3.00 3.00 4.00 4.00 5.00 5.00 6.00 6.00 7.00 7.00 Q (cfs) Time (hrs) PR-2 Hyd. No. 2 -- 10 Year Hyd No. 2 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Wednesday, 04 / 7 / 2021 Hyd. No. 3 PR-3 Hydrograph type = SCS Runoff Peak discharge = 26.52 cfs Storm frequency = 10 yrs Time to peak = 12.07 hrs Time interval = 1 min Hyd. volume = 90,314 cuft Drainage area = 5.430 ac Curve number = 96 Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = User Time of conc. (Tc) = 5.00 min Total precip. = 4.91 in Distribution = Type III Storm duration = 24 hrs Shape factor = 484 12 0 2 4 6 8 10 12 14 16 18 20 22 24 Q (cfs) 0.00 0.00 4.00 4.00 8.00 8.00 12.00 12.00 16.00 16.00 20.00 20.00 24.00 24.00 28.00 28.00 Q (cfs) Time (hrs) PR-3 Hyd. No. 3 -- 10 Year Hyd No. 3 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Wednesday, 04 / 7 / 2021 Hyd. No. 4 PR-4 Hydrograph type = SCS Runoff Peak discharge = 0.647 cfs Storm frequency = 10 yrs Time to peak = 12.07 hrs Time interval = 1 min Hyd. volume = 2,026 cuft Drainage area = 0.160 ac Curve number = 86 Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = User Time of conc. (Tc) = 5.00 min Total precip. = 4.91 in Distribution = Type III Storm duration = 24 hrs Shape factor = 484 13 0 2 4 6 8 10 12 14 16 18 20 22 24 26 Q (cfs) 0.00 0.00 0.10 0.10 0.20 0.20 0.30 0.30 0.40 0.40 0.50 0.50 0.60 0.60 0.70 0.70 0.80 0.80 0.90 0.90 1.00 1.00 Q (cfs) Time (hrs) PR-4 Hyd. No. 4 -- 10 Year Hyd No. 4 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Wednesday, 04 / 7 / 2021 Hyd. No. 5 Combined - Proposed Condition Hydrograph type = Combine Peak discharge = 35.23 cfs Storm frequency = 10 yrs Time to peak = 12.07 hrs Time interval = 1 min Hyd. volume = 119,380 cuft Inflow hyds. = 1, 2, 3, 4 Contrib. drain. area = 7.300 ac 14 0 2 4 6 8 10 12 14 16 18 20 22 24 Q (cfs) 0.00 0.00 10.00 10.00 20.00 20.00 30.00 30.00 40.00 40.00 Q (cfs) Time (hrs) Combined - Proposed Condition Hyd. No. 5 -- 10 Year Hyd No. 5 Hyd No. 1 Hyd No. 2 Hyd No. 3 Hyd No. 4 Hydrograph Summary Report 15 Hyd. Hydrograph Peak Time Time to Hyd. Inflow Maximum Total Hydrograph No. type flow interval Peak volume hyd(s) elevation strge used Description (origin) (cfs) (min) (min) (cuft) (ft) (cuft) 1 SCS Runoff 2.086 1 724 6,637 ------ ------ ------ PR-1 2 SCS Runoff 7.975 1 724 27,460 ------ ------ ------ PR-2 3 SCS Runoff 32.81 1 724 112,962 ------ ------ ------ PR-3 4 SCS Runoff 0.840 1 724 2,658 ------ ------ ------ PR-4 5 Combine 43.71 1 724 149,717 1, 2, 3, 4 ------ ------ Combined - Proposed Condition Proposed Condition.gpw Return Period: 25 Year Wednesday, 04 / 7 / 2021 Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Wednesday, 04 / 7 / 2021 Hyd. No. 1 PR-1 Hydrograph type = SCS Runoff Peak discharge = 2.086 cfs Storm frequency = 25 yrs Time to peak = 12.07 hrs Time interval = 1 min Hyd. volume = 6,637 cuft Drainage area = 0.390 ac Curve number = 87 Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = User Time of conc. (Tc) = 5.00 min Total precip. = 6.03 in Distribution = Type III Storm duration = 24 hrs Shape factor = 484 16 0 2 4 6 8 10 12 14 16 18 20 22 24 Q (cfs) 0.00 0.00 1.00 1.00 2.00 2.00 3.00 3.00 Q (cfs) Time (hrs) PR-1 Hyd. No. 1 -- 25 Year Hyd No. 1 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Wednesday, 04 / 7 / 2021 Hyd. No. 2 PR-2 Hydrograph type = SCS Runoff Peak discharge = 7.975 cfs Storm frequency = 25 yrs Time to peak = 12.07 hrs Time interval = 1 min Hyd. volume = 27,460 cuft Drainage area = 1.320 ac Curve number = 96 Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = User Time of conc. (Tc) = 5.00 min Total precip. = 6.03 in Distribution = Type III Storm duration = 24 hrs Shape factor = 484 17 0 2 4 6 8 10 12 14 16 18 20 22 24 Q (cfs) 0.00 0.00 2.00 2.00 4.00 4.00 6.00 6.00 8.00 8.00 Q (cfs) Time (hrs) PR-2 Hyd. No. 2 -- 25 Year Hyd No. 2 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Wednesday, 04 / 7 / 2021 Hyd. No. 3 PR-3 Hydrograph type = SCS Runoff Peak discharge = 32.81 cfs Storm frequency = 25 yrs Time to peak = 12.07 hrs Time interval = 1 min Hyd. volume = 112,962 cuft Drainage area = 5.430 ac Curve number = 96 Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = User Time of conc. (Tc) = 5.00 min Total precip. = 6.03 in Distribution = Type III Storm duration = 24 hrs Shape factor = 484 18 0 2 4 6 8 10 12 14 16 18 20 22 24 Q (cfs) 0.00 0.00 5.00 5.00 10.00 10.00 15.00 15.00 20.00 20.00 25.00 25.00 30.00 30.00 35.00 35.00 Q (cfs) Time (hrs) PR-3 Hyd. No. 3 -- 25 Year Hyd No. 3 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Wednesday, 04 / 7 / 2021 Hyd. No. 4 PR-4 Hydrograph type = SCS Runoff Peak discharge = 0.840 cfs Storm frequency = 25 yrs Time to peak = 12.07 hrs Time interval = 1 min Hyd. volume = 2,658 cuft Drainage area = 0.160 ac Curve number = 86 Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = User Time of conc. (Tc) = 5.00 min Total precip. = 6.03 in Distribution = Type III Storm duration = 24 hrs Shape factor = 484 19 0 2 4 6 8 10 12 14 16 18 20 22 24 Q (cfs) 0.00 0.00 0.10 0.10 0.20 0.20 0.30 0.30 0.40 0.40 0.50 0.50 0.60 0.60 0.70 0.70 0.80 0.80 0.90 0.90 1.00 1.00 Q (cfs) Time (hrs) PR-4 Hyd. No. 4 -- 25 Year Hyd No. 4 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Wednesday, 04 / 7 / 2021 Hyd. No. 5 Combined - Proposed Condition Hydrograph type = Combine Peak discharge = 43.71 cfs Storm frequency = 25 yrs Time to peak = 12.07 hrs Time interval = 1 min Hyd. volume = 149,717 cuft Inflow hyds. = 1, 2, 3, 4 Contrib. drain. area = 7.300 ac 20 0 2 4 6 8 10 12 14 16 18 20 22 24 Q (cfs) 0.00 0.00 10.00 10.00 20.00 20.00 30.00 30.00 40.00 40.00 50.00 50.00 Q (cfs) Time (hrs) Combined - Proposed Condition Hyd. No. 5 -- 25 Year Hyd No. 5 Hyd No. 1 Hyd No. 2 Hyd No. 3 Hyd No. 4 Hydrograph Summary Report 21 Hyd. Hydrograph Peak Time Time to Hyd. Inflow Maximum Total Hydrograph No. type flow interval Peak volume hyd(s) elevation strge used Description (origin) (cfs) (min) (min) (cuft) (ft) (cuft) 1 SCS Runoff 2.812 1 724 9,090 ------ ------ ------ PR-1 2 SCS Runoff 10.34 1 724 36,029 ------ ------ ------ PR-2 3 SCS Runoff 42.53 1 724 148,212 ------ ------ ------ PR-3 4 SCS Runoff 1.138 1 724 3,659 ------ ------ ------ PR-4 5 Combine 56.81 1 724 196,989 1, 2, 3, 4 ------ ------ Combined - Proposed Condition Proposed Condition.gpw Return Period: 100 Year Wednesday, 04 / 7 / 2021 Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Wednesday, 04 / 7 / 2021 Hyd. No. 1 PR-1 Hydrograph type = SCS Runoff Peak discharge = 2.812 cfs Storm frequency = 100 yrs Time to peak = 12.07 hrs Time interval = 1 min Hyd. volume = 9,090 cuft Drainage area = 0.390 ac Curve number = 87 Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = User Time of conc. (Tc) = 5.00 min Total precip. = 7.77 in Distribution = Type III Storm duration = 24 hrs Shape factor = 484 22 0 2 4 6 8 10 12 14 16 18 20 22 24 Q (cfs) 0.00 0.00 1.00 1.00 2.00 2.00 3.00 3.00 Q (cfs) Time (hrs) PR-1 Hyd. No. 1 -- 100 Year Hyd No. 1 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Wednesday, 04 / 7 / 2021 Hyd. No. 2 PR-2 Hydrograph type = SCS Runoff Peak discharge = 10.34 cfs Storm frequency = 100 yrs Time to peak = 12.07 hrs Time interval = 1 min Hyd. volume = 36,029 cuft Drainage area = 1.320 ac Curve number = 96 Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = User Time of conc. (Tc) = 5.00 min Total precip. = 7.77 in Distribution = Type III Storm duration = 24 hrs Shape factor = 484 23 0 2 4 6 8 10 12 14 16 18 20 22 24 Q (cfs) 0.00 0.00 2.00 2.00 4.00 4.00 6.00 6.00 8.00 8.00 10.00 10.00 12.00 12.00 Q (cfs) Time (hrs) PR-2 Hyd. No. 2 -- 100 Year Hyd No. 2 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Wednesday, 04 / 7 / 2021 Hyd. No. 3 PR-3 Hydrograph type = SCS Runoff Peak discharge = 42.53 cfs Storm frequency = 100 yrs Time to peak = 12.07 hrs Time interval = 1 min Hyd. volume = 148,212 cuft Drainage area = 5.430 ac Curve number = 96 Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = User Time of conc. (Tc) = 5.00 min Total precip. = 7.77 in Distribution = Type III Storm duration = 24 hrs Shape factor = 484 24 0 2 4 6 8 10 12 14 16 18 20 22 24 Q (cfs) 0.00 0.00 10.00 10.00 20.00 20.00 30.00 30.00 40.00 40.00 50.00 50.00 Q (cfs) Time (hrs) PR-3 Hyd. No. 3 -- 100 Year Hyd No. 3 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Wednesday, 04 / 7 / 2021 Hyd. No. 4 PR-4 Hydrograph type = SCS Runoff Peak discharge = 1.138 cfs Storm frequency = 100 yrs Time to peak = 12.07 hrs Time interval = 1 min Hyd. volume = 3,659 cuft Drainage area = 0.160 ac Curve number = 86 Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = User Time of conc. (Tc) = 5.00 min Total precip. = 7.77 in Distribution = Type III Storm duration = 24 hrs Shape factor = 484 25 0 2 4 6 8 10 12 14 16 18 20 22 24 Q (cfs) 0.00 0.00 1.00 1.00 2.00 2.00 Q (cfs) Time (hrs) PR-4 Hyd. No. 4 -- 100 Year Hyd No. 4 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Wednesday, 04 / 7 / 2021 Hyd. No. 5 Combined - Proposed Condition Hydrograph type = Combine Peak discharge = 56.81 cfs Storm frequency = 100 yrs Time to peak = 12.07 hrs Time interval = 1 min Hyd. volume = 196,989 cuft Inflow hyds. = 1, 2, 3, 4 Contrib. drain. area = 7.300 ac 26 0 2 4 6 8 10 12 14 16 18 20 22 24 Q (cfs) 0.00 0.00 10.00 10.00 20.00 20.00 30.00 30.00 40.00 40.00 50.00 50.00 60.00 60.00 Q (cfs) Time (hrs) Combined - Proposed Condition Hyd. No. 5 -- 100 Year Hyd No. 5 Hyd No. 1 Hyd No. 2 Hyd No. 3 Hyd No. 4 APPENDIX C Stormwater Collection System Calculations Project EVERGREEN WALK By IJAB Date 3/10/2021 Location South Windsor, CT Checked JEL Date 3/10/2021 Circle one:Present Developed Job No.140222801 1. Rational 'C' Runoff Coefficient & Area Calculations SF AC SF AC SF AC CCB A-1 20,076 0.461 18,904 0.434 1,172 0.027 94%0.86 CCB A-2 26,673 0.612 22,476 0.516 4,197 0.096 84%0.81 CCB A-3 9,325 0.214 7,994 0.184 1,331 0.031 86%0.81 TD A-1 1,970 0.045 1,579 0.036 391 0.009 80%0.78 CCB B-1 19,099 0.438 9,868 0.227 9,231 0.212 52%0.61 CCB B-2 2,306 0.053 2,306 0.053 0 0.000 100%0.90 CCB B-3 7,452 0.171 6,432 0.148 1,020 0.023 86%0.82 CCB B-4 6,012 0.138 4,771 0.110 1,241 0.028 79%0.78 CCB B-5 9,134 0.210 6,796 0.156 2,338 0.054 74%0.75 CCB B-6 12,046 0.277 8,228 0.189 3,818 0.088 68%0.71 WQU B-1 32,575 0.748 29,847 0.685 2,728 0.063 92%0.85 WQU B-2 9,855 0.226 9,789 0.225 66 0.002 99%0.90 YD B-1 6,395 0.147 517 0.012 5,878 0.135 8%0.35 YD B-2 3,615 0.083 152 0.003 3,463 0.079 4%0.33 YD B-3 18,165 0.417 12,398 0.285 5,767 0.132 68%0.71 YD B-4 3,759 0.086 3,017 0.069 742 0.017 80%0.78 YD B-5 37,840 0.869 34,841 0.800 2,999 0.069 92%0.85 YD B-6 4,526 0.104 4,167 0.096 359 0.008 92%0.85 RL B-1 6,132 0.141 6,132 0.141 0 0.000 100%0.90 RL B-2 6,000 0.138 6,000 0.138 0 0.000 100%0.90 RL B-3 20,000 0.459 20,000 0.459 0 0.000 100%0.90 RL B-4 20,000 0.459 20,000 0.459 0 0.000 100%0.90 EX CB-1 5,567 0.128 4,850 0.111 717 0.016 87%0.82 EX CB-2 7,200 0.165 5,391 0.124 1,809 0.042 75%0.75 Total Area Impervious (C=.9)Pervious (C=0.3) Catchment Area Percent Impervious C APPENDIX D Stormwater Quality Calculations WQV = water quality volume (acre-feet) WQF = water quality flow (cfs) R = volumetric runoff coefficient qu = unit peak discharge (cfs/mi2/inch) I = percent impervious cover A = drainage area (mi2) A = site area (acres)Q = runoff depth (watershed inches) = [WQV (acre-feet)]x[12 (inches/foot)] Drainage area (acres) Site Characteristics Description WQU A-1 Drainage Area to feature Area 1.33 acres 0.002078 mi^2 Impervious Area 1.17 acres 7761 Tc 0.08 hr I 88.0 % R = 0.05+ 0.009(I) =0.842 WQV =0.09 acre-ft 4,064 cf Q = WQV x 12/A = 0.84 inches determine qu using NRCS Runoff Curve Number P =1.0 inch CN = CN =90 Determine Ia, table 4-1 Chapter 4 TR-55 Ia = 0.222 Determine qu, Exhibit 4-III Chapter 4 TR-55 qu = 640 csm/in WQF =1.1 cfs Evergreen Walk South Windsor, CT BY DATE PROJ NO. CKD DATE SHEET 1 of 1 Engineering and Environmental Services i~åÖ~å 1000 [10 + 5P + 10Q - 10(Q2 + 1.25QP)1/2] IJAB 3/12/2021 140222801 JEL 3/12/2021 STORMWATER QUALITY CALCULATIONS Methodology:Water Quality Volume and Flow Reference:2004 Stormwater Quality Manual " WQV = water quality volume (acre-feet) WQF = water quality flow (cfs) R = volumetric runoff coefficient qu = unit peak discharge (cfs/mi2/inch) I = percent impervious cover A = drainage area (mi2) A = site area (acres)Q = runoff depth (watershed inches) = [WQV (acre-feet)]x[12 (inches/foot)] Drainage area (acres) Site Characteristics Description WQU B-1 Drainage Area to feature Area 3.86 acres 0.006031 mi^2 Impervious Area 3.21 acres 7761 Tc 0.08 hr I 83.2 % R = 0.05+ 0.009(I) =0.798 WQV =0.26 acre-ft 11,188 cf Q = WQV x 12/A = 0.80 inches determine qu using NRCS Runoff Curve Number P =1.0 inch CN = CN =90 Determine Ia, table 4-1 Chapter 4 TR-55 Ia = 0.222 Determine qu, Exhibit 4-III Chapter 4 TR-55 qu = 640 csm/in WQF =3.1 cfs Evergreen Walk South Windsor, CT BY DATE PROJ NO. CKD DATE SHEET 1 of 1 Engineering and Environmental Services JEL 3/12/2021 i~åÖ~å 1000 [10 + 5P + 10Q - 10(Q2 + 1.25QP)1/2] IJAB 3/12/2021 140222801 STORMWATER QUALITY CALCULATIONS Methodology:Water Quality Volume and Flow Reference:2004 Stormwater Quality Manual " WQV = water quality volume (acre-feet) WQF = water quality flow (cfs) R = volumetric runoff coefficient qu = unit peak discharge (cfs/mi2/inch) I = percent impervious cover A = drainage area (mi2) A = site area (acres)Q = runoff depth (watershed inches) = [WQV (acre-feet)]x[12 (inches/foot)] Drainage area (acres) Site Characteristics Description WQU B-2 Drainage Area to feature Area 0.73 acres 0.001141 mi^2 Impervious Area 0.58 acres 7761 Tc 0.08 hr I 79.5 % R = 0.05+ 0.009(I) =0.765 WQV =0.05 acre-ft 2,027 cf Q = WQV x 12/A = 0.77 inches determine qu using NRCS Runoff Curve Number P =1.0 inch CN = CN =90 Determine Ia, table 4-1 Chapter 4 TR-55 Ia = 0.222 Determine qu, Exhibit 4-III Chapter 4 TR-55 qu = 640 csm/in WQF =0.6 cfs Evergreen Walk South Windsor, CT BY DATE PROJ NO. CKD DATE SHEET 1 of 1 Engineering and Environmental Services JEL 3/12/2021 i~åÖ~å 1000 [10 + 5P + 10Q - 10(Q2 + 1.25QP)1/2] IJAB 3/12/2021 140222801 STORMWATER QUALITY CALCULATIONS Methodology:Water Quality Volume and Flow Reference:2004 Stormwater Quality Manual " APPENDIX E NOAA Atlas 14 Rainfall Depths and Intensities APPENDIX F Operation and Maintenance Plan Operation and Maintenance Manual 801 Evergreen Way South Windsor, Connecticut Regular inspection and maintenance of the stormwater management system and uphill areas is necessary to ensure proper operation. These costs will be the responsibility of the developer. Inspections of the stormwater management system should be conducted monthly based on the following table: Site Areas: General inspections shall be conducted monthly and after a storm event resulting in more than 2.5” of rain over a 24-hour period (1 year storm). Inspection and Maintenance Check for: Corrective Measure: Erosion Install erosion control measures and provide stabilization measures. Spillage Contain spill as close to source as possible with a dike of absorbent materials installed to protect drainage inlets, stormwater areas, or downstream wetlands and streams. All hazardous waste material, including absorbent materials must be disposed of by a licensed hazardous waste transporter and disposed of in an environmentally acceptable manner Sediment Accumulation Stabilize any disturbed areas uphill of where the sedimentation is occurring. Use temporary erosion control measures (i.e. silt fence, straw bales) to filter stormwater runoff. Trash Pick up and dispose of trash and litter in an environmentally acceptable manner. Routine Maintenance Maintenance Measure: Frequency: Surface Sweeping Parking area and truck court paved areas shall be swept annually between April 1st and July 1st. Catch Basins and Pipe: All catch basins shall be inspected annually between May 1st and September 15th. Inspection and Maintenance Check for: Corrective Measure: Trash, Sediment, Snow, Ice and Debris at Grate Remove trash, sediment, snow/ice and debris and dispose of in an environmentally acceptable manner. Sediment & Trash Accumulation in Sump Remove sediment from sumps if depth of deposits is greater than one-half the depth from the bottom of the catch basin to the invert of the lowest pipe in the basin. Pipe blockages Flush pipes to remove blockages. TV inspect as required. Operation and Maintenance Manual 801 Evergreen Way South Windsor, Connecticut At a minimum, the following maintenance measures shall be provided at the frequency listed in the following table: Routine Maintenance Maintenance Measure: Frequency: Sediment Removal Minimum once per year, between May 1st and September 15th: Remove sediment and trash from catch basin sumps and grates and pipe inverts. Dispose of sediment and trash in an environmentally acceptable manner. Catch basins shall be cleaned when accumulated material exceeds 1 foot. Rain Gardens Rain Gardens shall be inspected monthly. Inspect after every major storm during first 3 months of operation and monthly thereafter. Rain gardens shall be inspected for invasive vegetation every 6 months. Inspection and Maintenance Check for: Corrective Measure: Trash and Debris Remove trash and debris and dispose of in an environmentally acceptable manner. Invasive and dead vegetation Remove vegetation from rain garden. Revegetate as needed. At a minimum, the following maintenance measures shall be provided at the frequency listed in the following table: Routine Maintenance Maintenance Measure: Frequency: Mowing Twice a year: mow the buffer area. Remove trash and debris, grass clippings and accumulated organic matter. Mulch, fertilize, prune Annually Water Quality Units Water quality units shall be inspected and cleaned in strict accordance with the manufacturer’s recommendations and requirements. Clean the units using the method specified by the manufacturer. Wetland Mitigation Post-Construction 2023 Monitoring Report W hole Foods at The Promenade Shoppes at Evergreen Walk 801 Evergreen Way South Windsor, Connecticut Prepared for Charter Realty and Development Group c/o Karen Johnson, AICP 75 Holly Hill Lane, Suite 305 Greenwich, CT 06830 Prepared by All-Points Technology Corporation, P.C. 567 Vauxhall Street Ext. – Suite 311 Waterford, Connecticut 06385 November 2023 i Table of Contents Table of Contents Wetland Mitigation Post-Construction Monitoring Report No. 1 ....................... 1 Whole Foods at The Promenade Shoppes at Evergreen Walk ............................ 1 Table of Contents ................................................................................................................ 1 Location and Direction to Mitigation Site................................................................... 2 Start and Completion Dates for Mitigation ................................................................ 2 Wetland Mitigation Plan ................................................................................................... 3 Post-construction Monitoring ......................................................................................... 5 Performance Standards .................................................................................................... 5 Dates of Corrective or Maintenance Activities ......................................................... 6 Summary ................................................................................................................................ 7 Attachment A ........................................................................................................................ 8 Photodocumentation ......................................................................................................... 8 1 2023 Monitoring Report Project Summary The Town of South Windsor Inland Wetlands Agency (“IWA”) approved with issuance of Wetland Permit #21-22W, dated May 10, 2021, for the re-development and construction of a retail building, parking access road, stormwater management systems and associated utilities (“Facility” or the “Project”) on a portion of land west of Buckland Road and north of Hemlock Avenue in South Windsor, Connecticut (“Subject Property”). The Subject Property consists of ±48.34 acres of developed land situated in a Gateway Development (RC)-zoned area of the Town of South Windsor. This property includes retail buildings, paved roadways and parking areas, stormwater management systems, culverted wetland crossings, and landscaped areas. The re-development consisted of demolition of two existing buildings that previously existed on the Subject Property and construction of a ±50,000 square foot retail building occupied by Whole Foods. Approximately 2,600 square feet of wetlands, consisting of an intermittent watercourse, located to the north/northeast of the Project area . The singular wetland consists of a channelized intermittent watercourse with narrow seasonally saturated seeps that experiences artificial flooding events heavily influenced by local stormwater discharges from Buckland Road. The Project avoided impacts to the wetland system but resulted in ±21,650 square feet of impacts to the 80-foot upland review area. The upland review area consists of developed and disturbed areas associated with the previous retail development, paved areas and graded and armored slopes (e.g., retaining wall). A comprehensive mitigation plan that enhances various wetland functions and values to compensate for the unavoidable upland review area impacts was implemented in 2022. This plan included enhancement of ±5,000 square feet of the wetland through removal of invasive species and planting of native trees and shrubs. This report documents the first year of monitoring following completion of the Project in 2022 including the Intermittent Stream and Buffer Enhancement Area Plan (the “Plan”). All-Points Technology Corporation, P.C. (“APT”) acting as the Environmental Monitor for the Project provides the following information documenting the completion and status of the Plan for the first year of the required post-construction monitoring period. 2 2023 Monitoring Report Location and Direction to Mitigation Site The Subject Property is located along the west side of Buckland Road, north of Hemlock Avenue, west of Tamarack Avenue and south of newly constructed Cottonwood Lane in South Windsor, Connecticut. The property consists of ±48.34 acres and is identified as Map 27 Block 15 Unit 2 by the Town of South Windsor’s Tax Assessors Office. Access to the Subject Property exists via a paved driveway from Buckland Road and alternative access to the north from Tamarack Avenue or south from Evergreen Way. Start and Completion Dates for Mitigation Invasive treatment of enhancement area: 7/26/22 Wetland Enhancement Areas planting:10/5/22 Wetland Enhancement final inspection: 10/28/22 3 2023 Monitoring Report Wetland Mitigation Construction The following section describes the sequence of activities that occurred during improvements to the Intermittent Stream and Buffer Enhancement Area. All Plan work was performed under the direction of Charter Realty and its contractors with oversight provided by APT’s Environmental Monitor. Wetland Mitigation Plan A wetland scientist from APT experienced in wetland mitigation, invasive plant species identification, and removal/eradication served as the Environmental Monitor to ensure that the Plan was properly implemented, and sensitive wetland resources were properly protected. To the extent practical, wetland enhancement activities were performed during periods of low flow in the intermittent stream. Disturbed soils were generally stabilized by the end of the first full growing season following wetland mitigation activities. Foreign debris and litter observed was removed on the surface of the mitigation area and properly disposed of in accordance with all local, state and federal regulations. Soil disturbance was limited to planting locations. Exposed soils were mulched and seeded with an appropriate native seed mixture depending upon shade and soil moisture conditions of the affected areas. Fertilizer and pesticides in the wetland mitigation area was strictly prohibited and herbicide usage was limited to control invasive species. A pre-construction meeting was held on site between the project scientist and contractor(s) performing all aspects of the Plan. The primary intent of the meeting was to discuss the goals of the Plan and implementation of the required elements necessary to achieve these goals and general sequence of phasing of the Plan. Intermittent Stream and Buffer Enhancement Area Areas located within wetland areas and bordering the intermittent watercourse corridor were enhanced with the focus on improving wildlife habitat, water quality treatment, and aesthetic functions and values. Enhancement activities included the removal of target invasive shrub species and foreign debris and planting of a variety of native trees and shrubs within existing degraded areas that border the wetland complex. Areas receiving enhancement were colonized with, and dominated by a variety of non- native, invasive species such as autumn olive (Elaeagnus umbellata), Japanese honeysuckle (Lonicer sp.), multiflora rose (Rosa multiflora), and Asiatic bittersweet (Celastrus orbiculatus). Within these areas, invasive species were removed and treated with an appropriate herbicide, and native trees, shrubs and herbaceous vegetation were then planted following a waiting period to allow the herbicide to dissipate. In addition, foreign debris and litter that had accumulated on the surface within these areas was removed and properly disposed of in accordance with all local, state and federal regulations. Planting stock used in the enhancement area was inspected prior to installation for pests, disease and overall health to ensure suitable specimens were used. All planting stock was found to be in good health and free of disease/pests. All 4 2023 Monitoring Report woody plant stock was container-grown. The table below illustrates the planting schedule utilized; Intermittent Stream and Buffer Enhancement Area Planting Schedule Quantity Botanical Name Common Name Size1 Spacing2 10 Cornus amomum Silky Dogwood 3-4’ 5-10 feet 5 Cornus racemosa Gray Dogwood 3-4’ 5-10 feet 5 Juniperus communis Common Juniper 3-4’ 10 feet 10 Salix discolor Pussy Willow 3-4’ 5-10 feet 10 Viburnum lentago Nannyberry 3-4’ 5-10 feet 10 Aronia melanocarpa Black Chokeberry 3-4’ 5-10 feet 5 2023 Monitoring Report Post-construction Monitoring Since planting and invasive removal activities associated with the Plan occurred in 2022, the first year of post-construction monitoring occurred during the 2023 growing season. The following section discusses the current status of these areas during the 2023 growing season and their ability to meet the permit-required success standards. Representative photographs of these areas are provided in Attachment A. Post-construction monitoring measures the success of the Plan by the following conditions of approval as noted as performance standards on the permit-authorized site plans and the authorization letter dated May 10, 2021 by the Town of South Windsor IWA (Appl. #21-22W). Performance Standards The following performance (success) standards apply to wetland mitigation activities for this Project. The three performance standards were evaluated at the end of the 2023 growing season to determine if they are currently being met or not. 1) At least 75% of the surface area of the woody understory within the mitigation area should be restabilized with indigenous woody species. Response: This success standard is currently being met within the Intermittent Stream and Buffer Enhancement Area which contains approximately 75% coverage of native vegetation with minor tree and shrub mortality noted. Due to this success standard being met within the first monitoring year, no additional plantings are recommended at this time. 2) Vegetation should be checked to ensure that no more than 20% of the surface area is occupied by invasive woody species success standards. Response: An approximately 15-20% coverage of invasive species within the enhancement area was identified during the spring and fall 2023 monitoring inspections. Remedial action was not required in 2023. As such, this success standard is currently being met and therefore no additional treatment is recommended at this time. Soils within the mitigation area disturbed during implementation of this plan are permanently stabilized. Response: This success standard is being met as minimal areas were destabilized during the mitigation activities. Cut vegetation was left in place for woody material to breakdown and aid in slope stabilization. A dominance of native herbaceous vegetation was present during both inspections, no evidence of erosion was observed. 6 2023 Monitoring Report Dates of Corrective or Maintenance Activities The 2023 growing season represents the first year of monitoring following a full growing season after completion of treatment and planting of the enhancement area completed in 2022. Following the spring 2023 monitoring event a general lack of re-emergence of woody invasive species was noted which was confirmed in the fall 2023 monitoring period. As such, no maintenance activities were recommended in 20234. 7 2023 Monitoring Report Summary This report documents the Intermittent Watercourse and Buffer Enhancement Area was successfully constructed in general conformance with the IWA permit-approved site plans. Initial treatment and planting activities were completed in 2022 with minor additional activities required as noted during the 2023 monitoring period as a result of the reemergence of invasive woody shrubs and vines. Each of the three success standards are currently being met and/or exceeded during the 2023 monitoring period. As 2023 marks the first full growing season following completion of the Stream and Buffer Enhancement Area installation, it is APT’s opinion that monitoring observations made in 2023 document fulfillment of the monitoring program and no further monitoring is warranted. Attachment A Photodocumentation PHOTO DOCUMENTATION Evergreen Walk Whole Foods 501 Evergreen Way, South Windsor, Connecticut Photos taken on June 22 & September 28, 2023 Photo 2 View of routine mowing along top of retaining wall within ‘Meadow Mix A’ zone of Wetland Buffer Enhancement Area. Photo 1: View of mitigation plantings exhibiting signs of new growth. 1 PHOTO DOCUMENTATION Evergreen Walk Whole Foods 501 Evergreen Way, South Windsor, Connecticut Photos taken on June 22 & September 28, 2023 Photo 4 View of southern portion of Wetland Buffer Enhancement Area near culvert inlet. Note dominance of native species with limited re-emergence of bittersweet and multiflora rose. Photo 3: View of central Wetland Buffer Enhancement Area previously treated with herbicide. 2