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HomeMy WebLinkAboutDrainage ReportProposed Restaurants  Drainage Memorandum    Prepared for:  O’Connell Development Group  800 Kelly Way  Holyoke, MA 01040  SLR #141.21167.00001.0040    July 12, 2023  Drainage Memorandum  O’Connell Development Group  July 12, 2023  1        Drainage Memorandum  Proposed Restaurants  Cedar Avenue and Buckland Road  South Windsor, Connecticut  July 12, 2023  SLR #141.21167.00001.0040    This Drainage Memorandum has been prepared in support of the Site Plan of Development of new  restaurants within Unit 5 of the Evergreen Walk Development. This memorandum meets the  requirements of the Town of South Windsor Zoning Regulations, Section 6.6.5 Storm Drainage recognizing  the storm drainage infrastructure that has already been built as part of the overall development. The  project includes utility infrastructure to support the new restaurants and access drive through the site  with considerations for future development of the remainder of the Unit. The main vehicular access to  the site will be two‐way off Tamarack Avenue with an additional right‐in, right‐out access onto Cedar Ave.         Figure 1 – Project Area  Drainage Memorandum  O’Connell Development Group  July 12, 2023  2        Table 1 – Stormwater Data    Parcel Size Total 5.779 acres  Soil Characteristics Hydrologic Soil Group "B" and "C"  Nearest Water body Intermittent watercourse and Plum Gully  Brook  Federal Emergency Management Agency  (FEMA) Zone X  Proposed Impervious Coverage (People’s Bank  and New Restaurants) 56%  Proposed Land Use Open space, building, sidewalks, and  bituminous parking lot  Stormwater Treatment Practices ‐Capturing and treating the design water  quality flow (WQF)  ‐Removing at least 80 percent of the  average annual total suspended  solids (TSS) load  Water Quality Measures Proprietary stormwater treatment  Device ‐ Hydrodynamic Separator    STORMWATER MANAGEMENT APPROACH    Fuss & O’Neill prepared a Stormwater Management Report for the Evergreen Walk development in 2007.  In that report, this subject site (Unit 5) is referred to as "LA Fitness (Conceptual Design)". Unit 5 was  identified as an area not required to provide stormwater detention. The stormwater management  approach for this project follows the design of that prior report. Naturally, no calculations for zero net  increase of stormwater have been provided for this site as the prior report demonstrated that there will  be no deleterious downstream effects from an increase in stormwater discharge flow.     The stormwater management system has been designed utilizing Best Management Practices (BMPs) to  provide water quality management. The primary design goal is to treat the water quality flow (WQF), in  accordance with Connecticut Department of Energy & Environmental Protection (CTDEEP) requirements,  to provide the removal of total suspended solids and other potential stormwater pollutants prior to  discharge to the wetland adjacent vegetated buffer.     Existing drainage patterns will be maintained to the maximum extent practicable, and pollutant reduction  provided via a new proprietary stormwater treatment device (hydrodynamic separator [HDS]). The storm  drainage collection system will discharge into an off‐line HDS then discharge to a "bubble‐up level  spreader" where flows will spread over a rigid concrete level spreader lip and sheet flow through the stable  and heavily vegetated wetland buffer. Sheet flow over land through the CTDEEP "non developable area"  is permitted as long as it does not have erosive velocity. The attachments demonstrate the velocities from  the WQF and the 10‐year design storm event are within permissible ranges.       Drainage Memorandum  O’Connell Development Group  July 12, 2023  3        The computer program entitled Hydraflow Storm Sewers Extension for AutoCAD® Civil 3D® 2019 by  Autodesk, Inc., Version 2018.3, was used for designing the proposed storm drainage collection system.  Storm drainage computations performed include pipe capacity, hydraulic grade line calculations, and  gutter flow computations. The contributing watershed to each individual catch basin inlet was delineated  to determine the drainage area and land coverage. These values were used to determine the stormwater  runoff to each inlet using the Rational Method. The rainfall intensities for the site were obtained from the  National Oceanic and Atmospheric Administration (NOAA) Atlas 14, Volume 10, Precipitation Frequency  Data Server (PFDS). The proposed storm drainage system is designed to provide adequate capacity to  convey the 10‐year storm event in accordance with Section II 2.3.3 Design Storm Criteria of the South  Windsor Public Improvement Specifications.    WATER QUALITY MANAGEMENT    Stormwater runoff from the parking lot will be directed to the HDS (in an off‐line configuration) by  conventional catch basin and conveyance pipe network. Due to shallow groundwater (within 3.5 feet of  existing grade) encountered during geotechnical investigation, infiltration practices were not considered.    The proposed HDS will filter sediment and other pollutants that may be present in the stormwater runoff  from the proposed pavement areas prior to the stormwater flows reaching the level spreader. Refer to  the CDS Guide‐Operation, Design, Performance and Maintenance included as an attachment to this  memorandum. The CTDEEP 2004 Stormwater Quality Manual (Chapter 7) recommends methods for sizing  stormwater treatment measures with water quality volume (WQV) computations. The WQV addresses  the initial stormwater runoff, also commonly referred to as the "first‐ flush" runoff. The WQV provides  adequate volume to store the runoff associated with the first 1 inch of rainfall, which tends to contain the  highest concentration of potential pollutants. The WQF is the peak‐flow rate associated with the water  quality design storm or WQV. The HDS is in an offline configuration that directs and treats only the WQF  into the structure and permits remaining storm events to bypass the structure. Offline configurations are  ideal to prevent the resuspension of sediment. Supporting calculations have been included as an  attachment to this report.    CONCLUSION    The focus of the stormwater management approach was to provide water quality treatment and maintain  existing drainage patterns. Guidance from the original stormwater management report for the overall  development site was utilized in the design. The Stormwater Management Design meets the  recommendations set forth in the CTDEEP Stormwater Quality Manual and the criteria outlined in the Town  of South Windsor Zoning Regulations, Section 6.6.5 Storm Drainage.    All supporting documentation is attached to this report.     Drainage Memorandum  O’Connell Development Group  July 12, 2023  4        Attachments    Attachment A – FEMA Firmette Map  Attachment B – Natural Resources Conservation Service (NRCS) Soil Data  Attachment C – Soil Testing  Attachment D – Water Quality Computations  Attachment E – Hydrologic Analysis – Selected pages of Fuss & O’Neill Report (2007)  Attachment F – Storm Drainage Computations      21167.00001.0040.mr2823.drainage memo.docx        ATTACHMENT A    FEMA FIRMETTE MAP     Drainage Memorandum  Proposed Restaurant  Cedar Avenue and Buckland Road  South Windsor, Connecticut    July 12, 2023             ATTACHMENT B    NRCS SOIL DATA   Drainage Memorandum  Proposed Restaurant  Cedar Avenue and Buckland Road  South Windsor, Connecticut    July 12, 2023               ATTACHMENT C    SOIL TESTING  Drainage Memorandum  Proposed Restaurant  Cedar Avenue and Buckland Road  South Windsor, Connecticut    July 12, 2023                   ATTACHMENT D    WATER QUALITY COMPUTATIONS  Drainage Memorandum  Proposed Restaurant  Cedar Avenue and Buckland Road  South Windsor, Connecticut    July 12, 2023               ATTACHMENT E    HYDROLOGIC ANALYSIS – SELECTED PAGES FROM FUSS & O’NEILL  REPORT    Drainage Memorandum  Proposed Restaurant  Cedar Avenue and Buckland Road  South Windsor, Connecticut    July 12, 2023            ATTACHMENT F    STORM DRAINAGE COMPUTATIONS    Drainage Memorandum  Proposed Restaurant  Cedar Avenue and Buckland Road  South Windsor, Connecticut    July 12, 2023      National Flood Hazard Layer FIRMette 0 500 1,000 1,500 2,000250 Feet Ü SEE FIS REPORT FOR DETAILED LEGEND AND INDEX MAP FOR FIRM PANEL LAYOUT SPECIAL FLOODHAZARD AREAS Without Base Flood Elevation (BFE)Zone A, V, A99With BFE or DepthZone AE, AO, AH, VE, AR Regulatory Floodway 0.2% Annual Chance Flood Hazard, Areasof 1% annual chance flood with averagedepth less than one foot or with drainageareas of less than one square mileZone X Future Conditions 1% Annual Chance Flood HazardZone X Area with Reduced Flood Risk due to Levee. See Notes.Zone X Area with Flood Risk due to LeveeZone D NO SCREENArea of Minimal Flood Hazard Zone X Area of Undetermined Flood HazardZone D Channel, Culvert, or Storm Sewer Levee, Dike, or Floodwall Cross Sections with 1% Annual Chance 17.5 Water Surface Elevation Coastal Transect Coastal Transect Baseline Profile Baseline Hydrographic Feature Base Flood Elevation Line (BFE) Effective LOMRs Limit of Study Jurisdiction Boundary Digital Data Available No Digital Data Available Unmapped This map complies with FEMA's standards for the use of digital flood maps if it is not void as described below.The basemap shown complies with FEMA's basemapaccuracy standards The flood hazard information is derived directly from theauthoritative NFHL web services provided by FEMA. This mapwas exported on 8/18/2021 at 10:18 AM and does notreflect changes or amendments subsequent to this date andtime. The NFHL and effective information may change orbecome superseded by new data over time. This map image is void if the one or more of the following map elements do not appear: basemap imagery, flood zone labels, legend, scale bar, map creation date, community identifiers, FIRM panel number, and FIRM effective date. Map images for unmapped and unmodernized areas cannot be used for regulatory purposes. Legend OTHER AREAS OF FLOOD HAZARD OTHER AREAS GENERAL STRUCTURES OTHER FEATURES MAP PANELS 8 B 20.2 The pin displayed on the map is an approximatepoint selected by the user and does not representan authoritative property location. 1:6,000 72°33'34"W 41°49'11"N 72°32'56"W 41°48'45"N Basemap: USGS National Map: Orthoimagery: Data refreshed October, 2020 United States Department of Agriculture A product of the National Cooperative Soil Survey, a joint effort of the United States Department of Agriculture and other Federal agencies, State agencies including the Agricultural Experiment Stations, and local participants Custom Soil Resource Report for State of ConnecticutNatural Resources Conservation Service December 3, 2021 Soil Information for All Uses Soil Properties and Qualities The Soil Properties and Qualities section includes various soil properties and qualities displayed as thematic maps with a summary table for the soil map units in the selected area of interest. A single value or rating for each map unit is generated by aggregating the interpretive ratings of individual map unit components. This aggregation process is defined for each property or quality. Soil Qualities and Features Soil qualities are behavior and performance attributes that are not directly measured, but are inferred from observations of dynamic conditions and from soil properties. Example soil qualities include natural drainage, and frost action. Soil features are attributes that are not directly part of the soil. Example soil features include slope and depth to restrictive layer. These features can greatly impact the use and management of the soil. Hydrologic Soil Group Hydrologic soil groups are based on estimates of runoff potential. Soils are assigned to one of four groups according to the rate of water infiltration when the soils are not protected by vegetation, are thoroughly wet, and receive precipitation from long-duration storms. The soils in the United States are assigned to four groups (A, B, C, and D) and three dual classes (A/D, B/D, and C/D). The groups are defined as follows: Group A. Soils having a high infiltration rate (low runoff potential) when thoroughly wet. These consist mainly of deep, well drained to excessively drained sands or gravelly sands. These soils have a high rate of water transmission. Group B. Soils having a moderate infiltration rate when thoroughly wet. These consist chiefly of moderately deep or deep, moderately well drained or well drained soils that have moderately fine texture to moderately coarse texture. These soils have a moderate rate of water transmission. 22 Group C. Soils having a slow infiltration rate when thoroughly wet. These consist chiefly of soils having a layer that impedes the downward movement of water or soils of moderately fine texture or fine texture. These soils have a slow rate of water transmission. Group D. Soils having a very slow infiltration rate (high runoff potential) when thoroughly wet. These consist chiefly of clays that have a high shrink-swell potential, soils that have a high water table, soils that have a claypan or clay layer at or near the surface, and soils that are shallow over nearly impervious material. These soils have a very slow rate of water transmission. If a soil is assigned to a dual hydrologic group (A/D, B/D, or C/D), the first letter is for drained areas and the second is for undrained areas. Only the soils that in their natural condition are in group D are assigned to dual classes. Custom Soil Resource Report 23 24 Custom Soil Resource Report Map—Hydrologic Soil Group 46 3 2 1 1 0 46 3 2 1 5 0 46 3 2 1 9 0 46 3 2 2 3 0 46 3 2 2 7 0 46 3 2 3 1 0 46 3 2 3 5 0 46 3 2 1 1 0 46 3 2 1 5 0 46 3 2 1 9 0 46 3 2 2 3 0 46 3 2 2 7 0 46 3 2 3 1 0 46 3 2 3 5 0 46 3 2 3 9 0 702940 702980 703020 703060 703100 703140 703180 703220 703260 703300 703340 702940 702980 703020 703060 703100 703140 703180 703220 703260 703300 703340 41° 49' 2'' N 72 ° 3 3 ' 2 4 ' ' W 41° 49' 2'' N 72 ° 3 3 ' 6 ' ' W 41° 48' 53'' N 72 ° 3 3 ' 2 4 ' ' W 41° 48' 53'' N 72 ° 3 3 ' 6 ' ' W N Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 18N WGS84 0 50 100 200 300 Feet 0 25 50 100 150 Meters Map Scale: 1:1,990 if printed on A landscape (11" x 8.5") sheet. Soil Map may not be valid at this scale. MAP LEGEND MAP INFORMATION Area of Interest (AOI) Area of Interest (AOI) Soils Soil Rating Polygons A A/D B B/D C C/D D Not rated or not available Soil Rating Lines A A/D B B/D C C/D D Not rated or not available Soil Rating Points A A/D B B/D C C/D D Not rated or not available Water Features Streams and Canals Transportation Rails Interstate Highways US Routes Major Roads Local Roads Background Aerial Photography The soil surveys that comprise your AOI were mapped at 1:12,000. Warning: Soil Map may not be valid at this scale. Enlargement of maps beyond the scale of mapping can cause misunderstanding of the detail of mapping and accuracy of soil line placement. The maps do not show the small areas of contrasting soils that could have been shown at a more detailed scale. Please rely on the bar scale on each map sheet for map measurements. Source of Map: Natural Resources Conservation Service Web Soil Survey URL: Coordinate System: Web Mercator (EPSG:3857) Maps from the Web Soil Survey are based on the Web Mercator projection, which preserves direction and shape but distorts distance and area. A projection that preserves area, such as the Albers equal-area conic projection, should be used if more accurate calculations of distance or area are required. This product is generated from the USDA-NRCS certified data as of the version date(s) listed below. Soil Survey Area: State of Connecticut Survey Area Data: Version 21, Sep 7, 2021 Soil map units are labeled (as space allows) for map scales 1:50,000 or larger. Date(s) aerial images were photographed: Jul 15, 2019—Aug 29, 2019 The orthophoto or other base map on which the soil lines were compiled and digitized probably differs from the background imagery displayed on these maps. As a result, some minor shifting of map unit boundaries may be evident. Custom Soil Resource Report 25 Table—Hydrologic Soil Group Map unit symbol Map unit name Rating Acres in AOI Percent of AOI 12 Raypol silt loam C/D 0.1 1.0% 108 Saco silt loam B/D 0.0 0.2% 702A Tisbury silt loam, 0 to 3 percent slopes C 2.7 19.4% 704A Enfield silt loam, 0 to 3 percent slopes B 6.0 44.0% 704B Enfield silt loam, 3 to 8 percent slopes B 4.9 35.5% Totals for Area of Interest 13.8 100.0% Rating Options—Hydrologic Soil Group Aggregation Method: Dominant Condition Component Percent Cutoff: None Specified Tie-break Rule: Higher Custom Soil Resource Report 26 TAM A R A C K A V E N U E APPROXIMATE LOCATION OF FUTURE BUILDING PAD B-1 B-5 B-6 APPROXIMATE LOCATION OF PROPOSED BANK APPROXIMATE LOCATION OF FUTURE RESTAURANT B-4 B-3 B-2 SHEET NO. FIG. 2 RE V I S I O N S DATE PROJECT NO. DESIGNED RDG SCALE DRAWN RDG CHECKED JWK AUGUST 4, 2021 141.14899.00004 1"=50' S W N E SU B S U R F A C E E X P L O R A T I O N L O C A T I O N P L A N PR O P O S E D B A N K $ 1 '  ) 8 7 8 5 (  % 8 , / ' , 1 *  3 $ ' 6 CE D A R A V E N U E A N D B U C K L A N D R O A D SO U T H W I N D S O R , CO N N E C T I C U T 0'25' 50' 0 1/2"1" Co p y r i g h t M i l o n e & M a c B r o o m , I n c - 2 0 2 0 99 R E A L T Y D R I V E CH E S H I R E , C T 0 6 4 1 0 20 3 . 2 7 1 . 1 7 7 3 SL R C O N S U L T I N G . C O M NOTES: 1. BASEMAP DEVELOPED FROM AN ELECTRONIC FILE BY SLR TITLED "PROPERTY & TOPOGRAPHIC SURVEY" AND DATED 7/22/2021. 2. BORINGS BY SLR WERE PERFORMED BY SITE, LLC ON 7/30/2021. 3. THE LOCATIONS OF THESE BORINGS WERE LOCATED BY SURVEY. THESE LOCATIONS SHOULD BE CONSIDERED ACCURATE ONLY TO THE DEGREE IMPLIED BY THE METHOD USED. LEGEND: B-1 BORING BY SLR INTERNATIONAL CORPORATION (SLR) PROJECT: LOCATION: PROJ. NO: CLIENT: DATE: AUGER CASING SAMPLER COREBRL. HSA ‐SS ‐DATE TIME 2 1/4 ‐1 3/8 ‐2021‐07‐30 7:30 AM ‐‐140 ‐ ‐‐30 ‐ 1 2 1.0' 132.6' 4 3 5 10 3.0' 130.6' 19 12 4.5' 129.1' 6 10 22 22 30 50/4" S‐5 4 50/4" 19.8' 113.8' 1 UT = UNDISTURBED THINWALL 30 +  = HARD 30‐50 = DENSE 8‐15  = STIFF and    = 35% ‐ 50% 50+ = VERY DENSE 15‐30 = VERY STIFF 4‐10 = LOOSE 2‐4  =  SOFT S  =  SPLIT SPOON little   = 10% ‐ 20% 10‐30 = MEDIUM DENSE 4‐8  =  MEDIUM UP = UNDISTURBED PISTON some = 20% ‐ 35% PROPORTIONS Bottom of Exploration ±19.8' 21 0‐4 = VERY LOOSE 0‐2  =  VERY SOFT C  =  ROCK CORE trace  = <10% Remarks: 1. Auger refusal at ±19.8'.NON‐PLASTIC (SPT‐N) PLASTIC (SPT‐N) SAMPLE TYPE 20 22 18 19 15 17 S‐5: Very dense, reddish brown, fine to coarse SAND, little fine to coarse Gravel, little Silt. 12 9 13 10S‐4 11 10 S‐4: Very dense, reddish brown, fine to coarse SAND, some fine to coarse Gravel, little Silt. 7 8 5 6 S‐2: Medium dense, Top 8": Light brown, fine to medium SAND, some Silt. 3 Bottom 12": Reddish brown, fine to coarse SAND and fine to coarse GRAVEL, trace Silt. 4 S‐1: Loose, Top 10": Brown, fine to coarse SAND, some Silt, trace fine Gravel, trace Organics. 1 Bottom 6": Light brown, fine to medium SAND, some Silt, trace Organics. 2 EL E V .   (F T . ) Re m a r k BURMISTER SYSTEM (SOIL) U.S. CORPS OF ENGINEERS SYSTEM (ROCK) Depth    (FT) SAMPLE  NUMBER RECOVERY      (IN) BLOWS        PER 6"  SOIL AND ROCK CLASSIFICATION‐DESCRIPTION  DE P T H   (F T . ) STRATUM  DESCRIPTION SIZE ID (IN.)NOT ENCOUNTERED RIG MODEL:   HMR. WT (LB.) CME‐55 LCX HMR. FALL (IN.) TYPE WATER DEPTH TRACK W/ AUTOMATIC HAMMER EQUIPMENT:GROUNDWATER DEPTH (FT.)TYPE OF RIG: JULY 30, 2021 GROUND SURFACE ELEVATION: ±133.6' 141.14899.00004 FOREMAN: J. DEANGELIS PROPOSED BANK AND FUTURE BUILDING PADS BORING NO.: B‐1 SHEET: 1 of 1 CEDAR AVENUE & BUCKLAND ROAD, SOUTH WINDSOR, CT CONTRACTOR: SITE, LLC S‐3: Dense, reddish brown, fine to coarse SAND, some fine to coarse Gravel, little Silt. BORING LOG ACCUBRANCH INSPECTOR: R. GOWISNOCK S‐322 16 14 S‐116 S‐220 WEATHERED  BEDROCK TOPSOIL SUBSOIL SAND & GRAVEL SLR International Corporation, Inc. 99 Realty Drive, Cheshire, CT 06410 203.271.1773│www.slrconsulting.com PROJECT: LOCATION: PROJ. NO: CLIENT: DATE: AUGER CASING SAMPLER COREBRL. HSA ‐SS ‐DATE TIME 2 1/4 ‐1 3/8 ‐2021‐07‐30 8:30 AM ‐‐140 ‐ ‐‐30 ‐ 1 1 1.0' 141.6' 3 2 1 2 3.0' 139.6' 2 3.3'G.W.T.139.3' 4 8 12 12 9 8.5' 134.1' 12 10 13 14 13.5' 129.1' 41 50/3" 18.4' 124.2' 1 UT = UNDISTURBED THINWALL TOPSOIL SAND SUBSOIL GLACIAL TILL WEATHERED  BEDROCK BORING LOG ACCUBRANCH INSPECTOR: R. GOWISNOCK EQUIPMENT: PROPOSED BANK AND FUTURE BUILDING PADS BORING NO.: B‐2 SHEET: 1 of 1 CEDAR AVENUE & BUCKLAND ROAD, SOUTH WINDSOR, CT CONTRACTOR: SITE, LLC 141.14899.00004 FOREMAN: J. DEANGELIS HMR. FALL (IN.) JULY 30, 2021 GROUND SURFACE ELEVATION: ±142.6' TYPE WATER DEPTH TRACK W/ AUTOMATIC HAMMER GROUNDWATER DEPTH (FT.)TYPE OF RIG: RECOVERY      (IN) BLOWS        PER 6"  SOIL AND ROCK CLASSIFICATION‐DESCRIPTION  DE P T H   (F T . ) STRATUM  DESCRIPTION SIZE ID (IN.)±3.3'RIG MODEL:   HMR. WT (LB.) BURMISTER SYSTEM (SOIL) U.S. CORPS OF ENGINEERS SYSTEM (ROCK) CME‐55 LCX 1 Bottom 12": Light brown, fine to medium SAND and SILT, trace Organics. EL E V .   (F T . ) Re m a r k Depth    (FT) SAMPLE  NUMBER 2 S‐2: Loose, Top 12": Light brown, fine to medium SAND and SILT. 3 Bottom 6": Reddish brown, fine to coarse SAND, little Silt. S‐1: Loose, Top 7": Brown, fine to coarse SAND, some Silt, trace fine Gravel, trace Organics. S‐3: Medium dense, reddish brown, fine to coarse SAND, trace Silt. 22 7 5 10 S‐4: Medium dense, reddish brown, fine to coarse SAND, little fine to coarse Gravel, little Silt. 4 8 6 9 11 13 12 S‐422 14 15 S‐57 S‐5:Very dense, reddish fine to coarse SAND, little fine to coarse Gravel, little Silt. 16 17 18 19 Bottom of Exploration ±18.4' 20 21 22 Remarks: 1. Auger refusal at ±18.4'.NON‐PLASTIC (SPT‐N) PLASTIC (SPT‐N) SAMPLE TYPE PROPORTIONS 0‐4 = VERY LOOSE 0‐2  =  VERY SOFT C  =  ROCK CORE trace  = <10% 4‐10 = LOOSE 2‐4  =  SOFT S  =  SPLIT SPOON little   = 10% ‐ 20% 10‐30 = MEDIUM DENSE 4‐8  =  MEDIUM UP = UNDISTURBED PISTON some = 20% ‐ 35% 30‐50 = DENSE 8‐15  = STIFF and    = 35% ‐ 50% 50+ = VERY DENSE 15‐30 = VERY STIFF 30 +  = HARD S‐119 S‐218 S‐3 SLR International Corporation, Inc. 99 Realty Drive, Cheshire, CT 06410 203.271.1773│www.slrconsulting.com PROJECT: LOCATION: PROJ. NO: CLIENT: DATE: AUGER CASING SAMPLER COREBRL. HSA ‐SS ‐DATE TIME 2 1/4 ‐1 3/8 ‐2021‐07‐30 9:30 AM ‐‐140 ‐ ‐‐30 ‐ 1 2 1.0' 145.1' 2 3 2 3 3.0' 143.1' 4 9 4.5' 141.6' 5.1'G.W.T.141.0' 6 9 15 30 15 25 27 42 13.5' 132.6' 25 38 45 46 S‐6 3 50/3"20.3' 125.8' UT = UNDISTURBED THINWALL S‐421 S‐522 BORING LOG ACCUBRANCH INSPECTOR: R. GOWISNOCK PROPOSED BANK AND FUTURE BUILDING PADS BORING NO.: B‐3 SHEET: 1 of 1 CEDAR AVENUE & BUCKLAND ROAD, SOUTH WINDSOR, CT CONTRACTOR: SITE, LLC 141.14899.00004 FOREMAN: J. DEANGELIS JULY 30, 2021 GROUND SURFACE ELEVATION: ±146.1' EQUIPMENT:GROUNDWATER DEPTH (FT.)TYPE OF RIG: TYPE WATER DEPTH TRACK W/ AUTOMATIC HAMMER SIZE ID (IN.)±5.1'RIG MODEL:   HMR. WT (LB.) CME‐55 LCX HMR. FALL (IN.) Depth    (FT) SAMPLE  NUMBER RECOVERY      (IN) BLOWS        PER 6"  SOIL AND ROCK CLASSIFICATION‐DESCRIPTION  DE P T H   (F T . ) STRATUM  DESCRIPTION EL E V .   (F T . ) Re m a r k BURMISTER SYSTEM (SOIL) U.S. CORPS OF ENGINEERS SYSTEM (ROCK) 1 Bottom 12": Light brown, fine to medium SAND, some Silt, trace Organics.TOPSOIL SUBSOIL2S‐2: Loose, Top 12": Reddish brown, fine to medium SAND, some Silt. 3 Bottom 10": Reddish brown, fine to coarse SAND, little Silt. S‐119 S‐222 4 S‐1: Loose, Top 7": Dark brown, fine to meduim SAND, some Silt, trace fine Gravel, trace Organics. SAND 5 S‐3: Medium dense, reddish brown, fine to coarse SAND, little fine to coarse Gravel, little Silt. S‐3186 GLACIAL TILL 7 8 9 10 S‐4: Very dense, reddish brown, fine to coarse SAND, little fine to coarse Gravel, little Silt. WEATHERED  BEDROCK 11 12 13 14 15 S‐5: Very dense, reddish brown, fine to medium SAND and SILT, trace fine Gravel. 16 17 18 19 20 S‐6: Very dense, reddish brown, fine to coarse SAND,little fine to coarse Gravel, little Silt. 21 Bottom of Exploration ±20.3' 22 Remarks: ±NON‐PLASTIC (SPT‐N) PLASTIC (SPT‐N) SAMPLE TYPE PROPORTIONS 0‐4 = VERY LOOSE 0‐2  =  VERY SOFT C  =  ROCK CORE trace  = <10% 4‐10 = LOOSE 2‐4  =  SOFT S  =  SPLIT SPOON little   = 10% ‐ 20% 10‐30 = MEDIUM DENSE 4‐8  =  MEDIUM UP = UNDISTURBED PISTON some = 20% ‐ 35% 30‐50 = DENSE 8‐15  = STIFF and    = 35% ‐ 50% 50+ = VERY DENSE 15‐30 = VERY STIFF 30 +  = HARD SLR International Corporation, Inc. 99 Realty Drive, Cheshire, CT 06410 203.271.1773│www.slrconsulting.com PROJECT: LOCATION: PROJ. NO: CLIENT: DATE: AUGER CASING SAMPLER COREBRL. HSA ‐SS ‐DATE TIME 2 1/4 ‐1 3/8 ‐2021‐07‐30 10:30 AM ‐‐140 ‐ ‐‐30 ‐ 1 2 1.0' 136.8' 6 11 2.0' 135.8' 8 8 6 6 4.5' 133.3' 11 15 12 6.5' 131.3' 8 8.5' 129.3' 8 8 14 30 13.5' 124.3' S‐5 3 50/4" 18.5' 119.3' 1 UT = UNDISTURBED THINWALL SAND & SILT SAND BORING LOG ACCUBRANCH INSPECTOR: R. GOWISNOCK FILL TOPSOIL PROPOSED BANK AND FUTURE BUILDING PADS BORING NO.: B‐4 SHEET: 1 of 1 CEDAR AVENUE & BUCKLAND ROAD, SOUTH WINDSOR, CT CONTRACTOR: SITE, LLC 141.14899.00004 FOREMAN: J. DEANGELIS JULY 30, 2021 GROUND SURFACE ELEVATION: ±137.8' EQUIPMENT:GROUNDWATER DEPTH (FT.)TYPE OF RIG: TYPE WATER DEPTH TRACK W/ AUTOMATIC HAMMER SIZE ID (IN.)NOT ENCOUNTERED RIG MODEL:   HMR. WT (LB.) CME‐55 LCX HMR. FALL (IN.) Depth    (FT) SAMPLE  NUMBER RECOVERY      (IN) BLOWS        PER 6"  SOIL AND ROCK CLASSIFICATION‐DESCRIPTION  DE P T H   (F T . ) STRATUM  DESCRIPTION EL E V .   (F T . ) Re m a r k BURMISTER SYSTEM (SOIL) U.S. CORPS OF ENGINEERS SYSTEM (ROCK) 1 Bottom 6": Reddish brown, fine to coarse SAND and fine to coarse GRAVEL, trace Silt.  2 S‐2: Medium dense, light brown, fine to medium SAND, some Silt. SUBSOIL S‐1: Loose, Top 8": Brown, fine to coarse SAND, little Silt, trace fine Gravel, trace Organics. 3 S‐114 S‐220 4 5 S‐3: Medium dense, Top 12": Reddish brown, fine to coarse SAND, trace fine Gravel, trace Silt. S‐3186 Botttom 6": Reddish brown, fine to medium SAND and SILT. 7 8 9 10 S‐4: Medium dense, reddish brown, fine to coarse SAND, little fine to coarse Gravel, little Silt. S‐4 12 11 GLACIALTILL22 13 WEATHERED  BEDROCK 14 15 S‐5: Very dense, reddish brown, fine to coarse SAND, little fine to coarse Gravel, trace Silt. 16 17 18 19 Bottom of Exploration ±18.5' 20 21 22 Remarks: 1. Auger refusal at ±18.5'.NON‐PLASTIC (SPT‐N) PLASTIC (SPT‐N) SAMPLE TYPE PROPORTIONS 0‐4 = VERY LOOSE 0‐2  =  VERY SOFT C  =  ROCK CORE trace  = <10% 4‐10 = LOOSE 2‐4  =  SOFT S  =  SPLIT SPOON little   = 10% ‐ 20% 10‐30 = MEDIUM DENSE 4‐8  =  MEDIUM UP = UNDISTURBED PISTON some = 20% ‐ 35% 30‐50 = DENSE 8‐15  = STIFF and    = 35% ‐ 50% 50+ = VERY DENSE 15‐30 = VERY STIFF 30 +  = HARD SLR International Corporation, Inc. 99 Realty Drive, Cheshire, CT 06410 203.271.1773│www.slrconsulting.com PROJECT: LOCATION: PROJ. NO: CLIENT: DATE: AUGER CASING SAMPLER COREBRL. HSA ‐SS ‐DATE TIME 2 1/4 ‐1 3/8 ‐2021‐07‐30 11:30 AM ‐‐140 ‐ ‐‐30 ‐ 1 2 1.0' 137.3' 6 5 4 6 8 3.5' 134.8' 12 6 5.5' 132.8' 4 5 7 8.5' 129.8' S‐4 4 50/5" S‐5 4 50/5"15.4'G.W.T.122.9' UT = UNDISTURBED THINWALL S‐1: Loose, Top 8": Brown, fine to coarse SAND, little Silt, trace fine Gravel, trace Organics. BORING LOG PROPOSED BANK AND FUTURE BUILDING PADS BORING NO.: B‐5 SHEET: 1 of 1 CEDAR AVENUE & BUCKLAND ROAD, SOUTH WINDSOR, CT CONTRACTOR: SITE, LLC 141.14899.00004 FOREMAN: J. DEANGELIS ACCUBRANCH INSPECTOR: R. GOWISNOCK JULY 30, 2021 GROUND SURFACE ELEVATION: ±138.3' EQUIPMENT:GROUNDWATER DEPTH (FT.)TYPE OF RIG: TYPE WATER DEPTH TRACK W/ AUTOMATIC HAMMER SIZE ID (IN.)±15.3'RIG MODEL:   HMR. WT (LB.) CME‐55 LCX HMR. FALL (IN.) Depth    (FT) SAMPLE  NUMBER RECOVERY      (IN) BLOWS        PER 6"  SOIL AND ROCK CLASSIFICATION‐DESCRIPTION  DE P T H   (F T . ) STRATUM  DESCRIPTION EL E V .   (F T . ) Re m a r k BURMISTER SYSTEM (SOIL) U.S. CORPS OF ENGINEERS SYSTEM (ROCK) 1 Bottom 8": Light brown, fine to medium SAND, some Silt, trace Organics. 2 S‐2: Medium dense, Top 16": Light brown, fine to medium SAND, some Silt. TOPSOIL SUBSOIL 3 Bottom 6": Reddish brown, fine to coarse SAND, little Silt. S‐116 S‐222 4 SAND & SILT 5 S‐3: Loose, Top 6": Reddish brown, fine to medium SAND and SILT. S‐320 GLACIAL TILL 6 Bottom 14": Reddish brown, fine to coarse SAND, little fine to coarse Gravel, little Silt. 7 8 9 10 S‐4: Very dense, reddish brown, fine to coarse SAND, little fine to coarse Gravel, little Silt. 11 12 13 WEATHERED  BEDROCK 14 15 S‐5: Very dense, reddish brown, fine to coarse SAND, little fine to coarse Gravel, little Silt. 16 Bottom of Exploration ±15.4' 17 18 19 20 21 22 Remarks: ±NON‐PLASTIC (SPT‐N) PLASTIC (SPT‐N) SAMPLE TYPE PROPORTIONS 0‐4 = VERY LOOSE 0‐2  =  VERY SOFT C  =  ROCK CORE trace  = <10% 4‐10 = LOOSE 2‐4  =  SOFT S  =  SPLIT SPOON little   = 10% ‐ 20% 10‐30 = MEDIUM DENSE 4‐8  =  MEDIUM UP = UNDISTURBED PISTON some = 20% ‐ 35% 30‐50 = DENSE 8‐15  = STIFF and    = 35% ‐ 50% 50+ = VERY DENSE 15‐30 = VERY STIFF 30 +  = HARD SLR International Corporation, Inc. 99 Realty Drive, Cheshire, CT 06410 203.271.1773│www.slrconsulting.com PROJECT: LOCATION: PROJ. NO: CLIENT: DATE: AUGER CASING SAMPLER COREBRL. HSA ‐SS ‐DATE TIME 2 1/4 ‐1 3/8 ‐2021‐07‐30 1:00 PM ‐‐140 ‐ ‐‐30 ‐ 1 2 1.0' 140.9' 1 1 1 2 4 3.5'G.W.T.138.4' 9 9 11 8 6.5' 135.4' 7 8.5' 133.4' 6 6 10 10 38 50/1" 17.4' 124.5' 1 UT = UNDISTURBED THINWALL S‐1: Very loose, Top 8": Dark brown, fine to medium SAND, little Silt, trace fine Gravel, trace Organics. BORING LOG PROPOSED BANK AND FUTURE BUILDING PADS BORING NO.: B‐6 SHEET: 1 of 1 CEDAR AVENUE & BUCKLAND ROAD, SOUTH WINDSOR, CT CONTRACTOR: SITE, LLC 141.14899.00004 FOREMAN: J. DEANGELIS ACCUBRANCH INSPECTOR: R. GOWISNOCK JULY 30, 2021 GROUND SURFACE ELEVATION: ±141.9' EQUIPMENT:GROUNDWATER DEPTH (FT.)TYPE OF RIG: TYPE WATER DEPTH TRACK W/ AUTOMATIC HAMMER SIZE ID (IN.)±3.5'RIG MODEL:   HMR. WT (LB.) CME‐55 LCX HMR. FALL (IN.) Depth    (FT) SAMPLE  NUMBER RECOVERY      (IN) BLOWS        PER 6"  SOIL AND ROCK CLASSIFICATION‐DESCRIPTION  DE P T H   (F T . ) STRATUM  DESCRIPTION EL E V .   (F T . ) Re m a r k BURMISTER SYSTEM (SOIL) U.S. CORPS OF ENGINEERS SYSTEM (ROCK) 1 Bottom 6": Light brown, fine to medium SAND, some Silt, trace Organics. 2 S‐2: Loose, Top 14": Light brown, fine to medium SAND, some Silt. TOPSOIL SUBSOIL 3 Bottom 6": Reddish brown, fine to coarse SAND, little Silt. S‐114 S‐220 SAND 4 5 S‐3: Medium dense, Top 14": Reddish brown, fine to coarse SAND, little fine to coarse Gravel, trace Silt. S‐320 SAND & SILT 6 Bottom 6": Reddish brown, fine to medium SAND and SILT. 7 8 9 10 S‐4: Medium dense, reddish brown, fine to coarse SAND, little fine to coarse Gravel, little Silt. 11 S‐418 12 13 GLACIAL TILL 14 15 S‐57 S‐5: Very dense, reddish brown, fine to coarse SAND, little fine to coarse Gravel, little Silt. 16 17 18 Bottom of Exploration ±17.4' 19 20 21 22 Remarks: 1. Auger refusal at ±17.4'.NON‐PLASTIC (SPT‐N) PLASTIC (SPT‐N) SAMPLE TYPE PROPORTIONS 0‐4 = VERY LOOSE 0‐2  =  VERY SOFT C  =  ROCK CORE trace  = <10% 4‐10 = LOOSE 2‐4  =  SOFT S  =  SPLIT SPOON little   = 10% ‐ 20% 10‐30 = MEDIUM DENSE 4‐8  =  MEDIUM UP = UNDISTURBED PISTON some = 20% ‐ 35% 30‐50 = DENSE 8‐15  = STIFF and    = 35% ‐ 50% 50+ = VERY DENSE 15‐30 = VERY STIFF 30 +  = HARD SLR International Corporation, Inc. 99 Realty Drive, Cheshire, CT 06410 203.271.1773│www.slrconsulting.com Project 21167.00001 Made By: MCB Date: 7/12/2023 Chkd by: Date: CDS Unit Contributing Basins Imperv. Area (acres) Total Area (acres) Total 2.62 3.82 Table 4.1: WQV = (P)(Rv)(A)/12 =0.212 acre-feet Where: I = % of Impervious Cover = 69% Rv = volumetric runoff coeff. 0.05 + 0.009(I) =0.667 P = design precipitation (1.0" for water quality storm) = 1 inch A = site area (acres) = 3.82 acres = 0.0060 miles2 Q = runoff depth (in watershed inches) = [WQV(acrefeet)]*[12(inches/foot)]/drainage area (acres) Q = 0.667 CN = 1000 / [10+ 5P + 10Q -10(Q2 + 1.25QP)0.5] =97 Where: Q = runoff depth (in watershed inches) tc = 0.1 hours Type III Rainfall Distribution: From Table 4-1, Ia = 0.062 Ia/P = 0.062 From Exhibit 4-III, qu = 700 csm/in. WQF = (qu)(A)(Q) = 2.8 cfs CDS 2025-5 Flow = 3.2 cfs -> OK (TR-55) (TR-55) SLR Consulting COMPUTATION SHEET - WATER QUALITY FLOW (WQF) Subject:Proposed Restaurants WATER QUALITY FLOW Page 1 of 1 CDS Guide Operation, Design, Performance and Maintenance ENGINEERED SOLUTIONS 2 CDS® Using patented continuous deflective separation technology, the CDS system screens, separates and traps debris, sediment, and oil and grease from stormwater runoff. The indirect screening capability of the system allows for 100% removal of floatables and neutrally buoyant material without blinding. Flow and screening controls physically separate captured solids, and minimize the re-suspension and release of previously trapped pollutants. Inline units can treat up to 6 cfs, and internally bypass flows in excess of 50 cfs (1416 L/s). Available precast or cast-in- place, offline units can treat flows from 1 to 300 cfs (28.3 to 8495 L/s). The pollutant removal capacity of the CDS system has been proven in lab and field testing. Operation Overview Stormwater enters the diversion chamber where the diversion weir guides the flow into the unit’s separation chamber and pollutants are removed from the flow. All flows up to the system’s treatment design capacity enter the separation chamber and are treated. Swirl concentration and screen deflection force floatables and solids to the center of the separation chamber where 100% of floatables and neutrally buoyant debris larger than the screen apertures are trapped. Stormwater then moves through the separation screen, under the oil baffle and exits the system. The separation screen remains clog free due to continuous deflection. During the flow events exceeding the treatment design capacity, the diversion weir bypasses excessive flows around the separation chamber, so captured pollutants are retained in the separation cylinder. Design Basics There are three primary methods of sizing a CDS system. The Water Quality Flow Rate Method determines which model size provides the desired removal efficiency at a given flow rate for a defined particle size. The Rational Rainfall Method™ or the and Probabilistic Method is used when a specific removal efficiency of the net annual sediment load is required. Typically in the Unites States, CDS systems are designed to achieve an 80% annual solids load reduction based on lab generated performance curves for a gradation with an average particle size (d50) of 125 microns (μm). For some regulatory environments, CDS systems can also be designed to achieve an 80% annual solids load reduction based on an average particle size (d50) of 75 microns (μm) or 50 microns (μm). Water Quality Flow Rate Method In some cases, regulations require that a specific treatment rate, often referred to as the water quality design flow (WQQ), be treated. This WQQ represents the peak flow rate from either an event with a specific recurrence interval, e.g. the six-month storm, or a water quality depth, e.g. 1/2-inch (13 mm) of rainfall. The CDS is designed to treat all flows up to the WQQ. At influent rates higher than the WQQ, the diversion weir will direct most flow exceeding the WQQ around the separation chamber. This allows removal efficiency to remain relatively constant in the separation chamber and eliminates the risk of washout during bypass flows regardless of influent flow rates. Treatment flow rates are defined as the rate at which the CDS will remove a specific gradation of sediment at a specific removal efficiency. Therefore the treatment flow rate is variable, based on the gradation and removal efficiency specified by the design engineer. Rational Rainfall Method™ Differences in local climate, topography and scale make every site hydraulically unique. It is important to take these factors into consideration when estimating the long-term performance of any stormwater treatment system. The Rational Rainfall Method combines site-specific information with laboratory generated performance data, and local historical precipitation records to estimate removal efficiencies as accurately as possible. Short duration rain gauge records from across the United States and Canada were analyzed to determine the percent of the total annual rainfall that fell at a range of intensities. US stations’ depths were totaled every 15 minutes, or hourly, and recorded in 0.01-inch increments. Depths were recorded hourly with 1-mm resolution at Canadian stations. One trend was consistent at all sites; the vast majority of precipitation fell at low intensities and high intensity storms contributed relatively little to the total annual depth. These intensities, along with the total drainage area and runoff coefficient for each specific site, are translated into flow rates using the Rational Rainfall Method. Since most sites are relatively small and highly impervious, the Rational Rainfall Method is appropriate. Based on the runoff flow rates calculated for each intensity, operating rates within a proposed CDS system are GRATE INLET(CAST IRON HOOD FORCURB INLET OPENING) CREST OF BYPASS WEIR(ONE EACH SIDE) INLET(MULTIPLE PIPES POSSIBLE) OIL BAFFLE SUMP STORAGESEPARATION SLAB TREATMENT SCREEN OUTLET INLET FLUME SEPARATION CYLINDER CLEAN OUT(REQUIRED) DEFLECTION PAN, 3 SIDED(GRATE INLET DESIGN) 3 determined. Performance efficiency curve determined from full scale laboratory tests on defined sediment PSDs is applied to calculate solids removal efficiency. The relative removal efficiency at each operating rate is added to produce a net annual pollutant removal efficiency estimate. Probabilistic Rational Method The Probabilistic Rational Method is a sizing program Contech developed to estimate a net annual sediment load reduction for a particular CDS model based on site size, site runoff coefficient, regional rainfall intensity distribution, and anticipated pollutant characteristics. The Probabilistic Method is an extension of the Rational Method used to estimate peak discharge rates generated by storm events of varying statistical return frequencies (e.g. 2-year storm event). Under the Rational Method, an adjustment factor is used to adjust the runoff coefficient estimated for the 10-year event, correlating a known hydrologic parameter with the target storm event. The rainfall intensities vary depending on the return frequency of the storm event under consideration. In general, these two frequency dependent parameters (rainfall intensity and runoff coefficient) increase as the return frequency increases while the drainage area remains constant. These intensities, along with the total drainage area and runoff coefficient for each specific site, are translated into flow rates using the Rational Method. Since most sites are relatively small and highly impervious, the Rational Method is appropriate. Based on the runoff flow rates calculated for each intensity, operating rates within a proposed CDS are determined. Performance efficiency curve on defined sediment PSDs is applied to calculate solids removal efficiency. The relative removal efficiency at each operating rate is added to produce a net annual pollutant removal efficiency estimate. Treatment Flow Rate The inlet throat area is sized to ensure that the WQQ passes through the separation chamber at a water surface elevation equal to the crest of the diversion weir. The diversion weir bypasses excessive flows around the separation chamber, thus preventing re-suspension or re-entrainment of previously captured particles. Hydraulic Capacity The hydraulic capacity of a CDS system is determined by the length and height of the diversion weir and by the maximum allowable head in the system. Typical configurations allow hydraulic capacities of up to ten times the treatment flow rate. The crest of the diversion weir may be lowered and the inlet throat may be widened to increase the capacity of the system at a given water surface elevation. The unit is designed to meet project specific hydraulic requirements. Performance Full-Scale Laboratory Test Results A full-scale CDS system (Model CDS2020-5B) was tested at the facility of University of Florida, Gainesville, FL. This CDS unit was evaluated under controlled laboratory conditions of influent flow rate and addition of sediment. Two different gradations of silica sand material (UF Sediment & OK-110) were used in the CDS performance evaluation. The particle size distributions (PSDs) of the test materials were analyzed using standard method “Gradation ASTM D-422 “Standard Test Method for Particle-Size Analysis of Soils” by a certified laboratory. UF Sediment is a mixture of three different products produced by the U.S. Silica Company: “Sil-Co-Sil 106”, “#1 DRY” and “20/40 Oil Frac”. Particle size distribution analysis shows that the UF Sediment has a very fine gradation (d50 = 20 to 30 μm) covering a wide size range (Coefficient of Uniformity, C averaged at 10.6). In comparison with the hypothetical TSS gradation specified in the NJDEP (New Jersey Department of Environmental Protection) and NJCAT (New Jersey Corporation for Advanced Technology) protocol for lab testing, the UF Sediment covers a similar range of particle size but with a finer d50 (d50 for NJDEP is approximately 50 μm) (NJDEP, 2003). The OK-110 silica sand is a commercial product of U.S. Silica Sand. The particle size distribution analysis of this material, also included in Figure 1, shows that 99.9% of the OK-110 sand is finer than 250 microns, with a mean particle size (d50) of 106 microns. The PSDs for the test material are shown in Figure 1. Figure 1. Particle size distributions Tests were conducted to quantify the performance of a specific CDS unit (1.1 cfs (31.3-L/s) design capacity) at various flow rates, ranging from 1% up to 125% of the treatment design capacity of the unit, using the 2400 micron screen. All tests were conducted with controlled influent concentrations of approximately 200 mg/L. Effluent samples were taken at equal time intervals across the entire duration of each test run. These samples were then processed with a Dekaport Cone sample splitter to obtain representative sub-samples for Suspended Sediment Concentration (SSC) testing using ASTM D3977-97 “Standard Test Methods for Determining Sediment Concentration in Water Samples”, and particle size distribution analysis. Results and Modeling Based on the data from the University of Florida, a performance model was developed for the CDS system. A regression analysis was used to develop a fitting curve representative of the scattered data points at various design flow rates. This model, which demonstrated good agreement with the laboratory data, can then be used to predict CDS system performance with respect 4 to SSC removal for any particle size gradation, assuming the particles are inorganic sandy-silt. Figure 2 shows CDS predictive performance for two typical particle size gradations (NJCAT gradation and OK-110 sand) as a function of operating rate. Figure 2. CDS stormwater treatment predictive performance for various particle gradations as a function of operating rate. Many regulatory jurisdictions set a performance standard for hydrodynamic devices by stating that the devices shall be capable of achieving an 80% removal efficiency for particles having a mean particle size (d50) of 125 microns (e.g. Washington State Department of Ecology — WASDOE - 2008). The model can be used to calculate the expected performance of such a PSD (shown in Figure 3). The model indicates (Figure 4) that the CDS system with 2400 micron screen achieves approximately 80% removal at the design (100%) flow rate, for this particle size distribution (d50 = 125 μm). Figure 3. WASDOE PSD Figure 4. Modeled performance for WASDOE PSD. Maintenance The CDS system should be inspected at regular intervals and maintained when necessary to ensure optimum performance. The rate at which the system collects pollutants will depend more heavily on site activities than the size of the unit. For example, unstable soils or heavy winter sanding will cause the grit chamber to fill more quickly but regular sweeping of paved surfaces will slow accumulation. Inspection Inspection is the key to effective maintenance and is easily performed. Pollutant transport and deposition may vary from year to year and regular inspections will help ensure that the system is cleaned out at the appropriate time. At a minimum, inspections should be performed twice per year (e.g. spring and fall) however more frequent inspections may be necessary in climates where winter sanding operations may lead to rapid accumulations, or in equipment washdown areas. Installations should also be inspected more frequently where excessive amounts of trash are expected. The visual inspection should ascertain that the system components are in working order and that there are no blockages or obstructions in the inlet and separation screen. The inspection should also quantify the accumulation of hydrocarbons, trash, and sediment in the system. Measuring pollutant accumulation can be done with a calibrated dipstick, tape measure or other measuring instrument. If absorbent material is used for enhanced removal of hydrocarbons, the level of discoloration of the sorbent material should also be identified 5 during inspection. It is useful and often required as part of an operating permit to keep a record of each inspection. A simple form for doing so is provided. Access to the CDS unit is typically achieved through two manhole access covers. One opening allows for inspection and cleanout of the separation chamber (cylinder and screen) and isolated sump. The other allows for inspection and cleanout of sediment captured and retained outside the screen. For deep units, a single manhole access point would allows both sump cleanout and access outside the screen. The CDS system should be cleaned when the level of sediment has reached 75% of capacity in the isolated sump or when an appreciable level of hydrocarbons and trash has accumulated. If absorbent material is used, it should be replaced when significant discoloration has occurred. Performance will not be impacted until 100% of the sump capacity is exceeded however it is recommended that the system be cleaned prior to that for easier removal of sediment. The level of sediment is easily determined by measuring from finished grade down to the top of the sediment pile. To avoid underestimating the level of sediment in the chamber, the measuring device must be lowered to the top of the sediment pile carefully. Particles at the top of the pile typically offer less resistance to the end of the rod than consolidated particles toward the bottom of the pile. Once this measurement is recorded, it should be compared to the as-built drawing for the unit to determine weather the height of the sediment pile off the bottom of the sump floor exceeds 75% of the total height of isolated sump. Cleaning Cleaning of a CDS systems should be done during dry weather conditions when no flow is entering the system. The use of a vacuum truck is generally the most effective and convenient method of removing pollutants from the system. Simply remove the manhole covers and insert the vacuum hose into the sump. The system should be completely drained down and the sump fully evacuated of sediment. The area outside the screen should also be cleaned out if pollutant build-up exists in this area. In installations where the risk of petroleum spills is small, liquid contaminants may not accumulate as quickly as sediment. However, the system should be cleaned out immediately in the event of an oil or gasoline spill. Motor oil and other hydrocarbons that accumulate on a more routine basis should be removed when an appreciable layer has been captured. To remove these pollutants, it may be preferable to use absorbent pads since they are usually less expensive to dispose than the oil/water emulsion that may be created by vacuuming the oily layer. Trash and debris can be netted out to separate it from the other pollutants. The screen should be cleaned to ensure it is free of trash and debris. Manhole covers should be securely seated following cleaning activities to prevent leakage of runoff into the system from above and also to ensure that proper safety precautions have been followed. Confined space entry procedures need to be followed if physical access is required. Disposal of all material removed from the CDS system should be done in accordance with local regulations. In many jurisdictions, disposal of the sediments may be handled in the same manner as the disposal of sediments removed from catch basins or deep sump manholes. Check your local regulations for specific requirements on disposal. 6 Note: To avoid underestimating the volume of sediment in the chamber, carefully lower the measuring device to the top of the sediment pile. Finer silty particles at the top of the pile may be more difficult to feel with a measuring stick. These finer particles typically offer less resistance to the end of the rod than larger particles toward the bottom of the pile. CDS Model Diameter Distance from Water Surface to Top of Sediment Pile Sediment Storage Capacity ft m ft m y3 m3 CDS1515 3 0.9 3.0 0.9 0.5 0.4 CDS2015 4 1.2 3.0 0.9 0.9 0.7 CDS2015 5 1.5 3.0 0.9 1.3 1.0 CDS2020 5 1.5 3.5 1.1 1.3 1.0 CDS2025 5 1.5 4.0 1.2 1.3 1.0 CDS3020 6 1.8 4.0 1.2 2.1 1.6 CDS3025 6 1.8 4.0 1.2 2.1 1.6 CDS3030 6 1.8 4.6 1.4 2.1 1.6 CDS3035 6 1.8 5.0 1.5 2.1 1.6 CDS4030 8 2.4 4.6 1.4 5.6 4.3 CDS4040 8 2.4 5.7 1.7 5.6 4.3 CDS4045 8 2.4 6.2 1.9 5.6 4.3 CDS5640 10 3.0 6.3 1.9 8.7 6.7 CDS5653 10 3.0 7.7 2.3 8.7 6.7 CDS5668 10 3.0 9.3 2.8 8.7 6.7 CDS5678 10 3.0 10.3 3.1 8.7 6.7 Table 1: CDS Maintenance Indicators and Sediment Storage Capacities 7 CDS Inspection & Maintenance Log CDS Model: Location: Water Floatable Describe Maintenance Date depth to Layer Maintenance Personnel Comments sediment1 Thickness2 Performed —————————————————————————————————————————————————————————— —————————————————————————————————————————————————————————— —————————————————————————————————————————————————————————— —————————————————————————————————————————————————————————— —————————————————————————————————————————————————————————— —————————————————————————————————————————————————————————— —————————————————————————————————————————————————————————— —————————————————————————————————————————————————————————— —————————————————————————————————————————————————————————— —————————————————————————————————————————————————————————— —————————————————————————————————————————————————————————— —————————————————————————————————————————————————————————— —————————————————————————————————————————————————————————— —————————————————————————————————————————————————————————— 1. The water depth to sediment is determined by taking two measurements with a stadia rod: one measurement from the manhole opening to the top of the sediment pile and the other from the manhole opening to the water surface. If the difference between these measurements is less than the values listed in table 1 the system should be cleaned out. Note: to avoid underestimating the volume of sediment in the chamber, the measuring device must be carefully lowered to the top of the sediment pile. 2. For optimum performance, the system should be cleaned out when the floating hydrocarbon layer accumulates to an appreciable thickness. In the event of an oil spill, the system should be cleaned immediately. SUPPORT • Drawings and specifications are available at www.ContechES.com. • Site-specific design support is available from our engineers. ©2017 Contech Engineered Solutions LLC, a QUIKRETE Company Contech Engineered Solutions provides site solutions for the civil engineering industry. Contech’s portfolio includes bridges, drainage, sanitary sewer, earth stabilization and stormwater treatment products. For information on other Contech division offerings, visit www.ContechES.com or call 800.338.1122 NOTHING IN THIS CATALOG SHOULD BE CONSTRUED AS A WARRANTY. APPLICATIONS SUGGESTED HEREIN ARE DESCRIBED ONLY TO HELP READERS MAKE THEIR OWN EVALUATIONS AND DECISIONS, AND ARE NEITHER GUARANTEES NOR WARRANTIES OF SUITABILITY FOR ANY APPLICATION. CONTECH MAKES NO WARRANTY WHATSOEVER, EXPRESS OR IMPLIED, RELATED TO THE APPLICATIONS, MATERIALS, COATINGS, OR PRODUCTS DISCUSSED HEREIN. ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND ALL IMPLIED WARRANTIES OF FITNESS FOR ANY PARTICULAR PURPOSE ARE DISCLAIMED BY CONTECH. SEE CONTECH’S CONDITIONS OF SALE (AVAILABLE AT WWW.CONTECHES.COM/COS) FOR MORE INFORMATION. The product(s) described may be protected by one or more of the following US patents: 5,322,629; 5,624,576; 5,707,527; 5,759,415; 5,788,848; 5,985,157; 6,027,639; 6,350,374; 6,406,218; 6,641,720; 6,511,595; 6,649,048; 6,991,114; 6,998,038; 7,186,058; 7,296,692; 7,297,266; related foreign patents or other patents pending. 800-338-1122 www.ContechES.com cds_manual 3/17 PDF ENGINEERED SOLUTIONS D ECHN39,820 sf EXTENSION O F HEMLOCK AV E N U E Recreation below±15,000 SF L.A.Fitness 45,000 sf Expansion15,000 sf W A T E R / E C OA R E A D D 1 LEVEL PKG-DECK EXIST./APPROVED 90,250 SF284,750 SF 229.9 AC. 13.1 AC. 243 AC. Wright PropertyThe 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 SF3,870 SF Office - South I & II ECHN Medical CenterThe Shops at Evergreen Walk - BUILDINGS, OFFICE PROPOSED 58,800 SF Office - West, A, B, C, D, E, F, G 447,510 SFTOTAL506,310 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 Rooms250 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 EX. C A R T PATH LOO P BOA R D W A L K BOA R D W A L K WET M E A D O W EVE R G R E E N WAL K WALKING / JOGGING TRAIL WALKING / JOGGING TRAIL 1 LEVEL PKG-DECK 1 LEVEL PKG-DECK1 LEVEL PKG-DECK ± 6,000 SF ± 5,00 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 RETAIL20 RES. UNITS ABOVE100' DEPTH RETAIL, 1 ST.±56,000 SF RESIDENTIAL.25 UNITS ± 6,000 SF ±22,000 s f R E T A I L 15 RES. U N I T S A B O V E 100' DEPTH ±12,000 s f R E T A I L 15 RES. U N I T S A B O V E 70' D E P T H ±12,000sf RETAIL20 RES. UNITS ABOVE 70' DEPTH ±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 ± 5,00 0 S F Retail±5,000 SF Retail±10,000 SF Retail±12,000 SFRetail±9,000 SF Retail±19,000 SF Retail±12,000 SF Retail±8,000 SF Retail±13,000 SF Retail±7,000SF OFFICE-WEST±18,200 sf OFFICE-SOUTH II 29,400 SF OFFICE-SOUTH I29,400 SF OFFICE - A 50,000 SF/ 3 ST. OFFICE - B40,000 SF/ 3 ST. OFFICE - C 32,500 SF/ 2 ST. OFFICE - D 100,000 sf / 4 st. OFFICE -E40,000/4ST. HOTEL 125 ROOM / 4ST. OFFICE-F91,810 sf4 story OFFICE-G75,000 sf3 story HOTEL 125 ROOM / 4ST. Retail6,000 SF Retail5,000 SF Retail15,000 SF Retail24,000 SF EXTENSION OF CEDAR AVENUE LM A N : CT B : MS V I E W : UC S : PROJ. No.: DATE: DATUM: SCALE: HORZ.: VERT.: HORZ.: VERT.: Fil e P a t h : J : \ D W G \ P 2 0 0 0 \ 4 8 1 \ A 3 0 - G e n C o n s u l t \ 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 M o n , J u l 3 0 , 2 0 0 7 - 1 0 : 1 0 A M U s e r : H B u s c h 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 Project: By: MCB Date: 7/12/23 Location: Checked: Date: Basin Name Impervious Area C=0.9 (sf) Grassed Area C=0.3 (sf) Wooded Area C=0.2 (sf) Total Area (sf) Total Area (ac) Weighted C Tc (min) CCB 1 7098 1858 0 8956 0.21 0.78 5.0 CCB 5 6412 1262 0 7674 0.18 0.80 5.0 CCB 6 5669 1205 0 6874 0.16 0.79 5.0 CCB 8 3926 1205 0 5580 0.13 0.70 5.0 CCB 9 4599 1440 0 6039 0.14 0.76 5.0 CCB 10 5757 3091 0 8848 0.20 0.69 5.0 CCB 11 1665 967 0 2632 0.06 0.68 5.0 CCB 12 5090 814 0 5904 0.14 0.82 5.0 CLCB 13 12485 11700 0 24185 0.56 0.61 5.0 CCB 14 9548 5707 0 15255 0.35 0.68 5.0 CCB 16 4730 2888 0 7618 0.17 0.67 5.0 CCB 17 4319 616 0 4935 0.11 0.83 5.0 CCB 18 7398 2089 0 9487 0.22 0.77 5.0 CCB 19 4912 2859 0 7771 0.18 0.68 5.0 EX SYSTEM 20276 14042 0 34318 0.79 0.65 5.0 Rational Method Individual Basin Calculations Proposed Restaurants South Windsor, Connecticut SLR International Corporation, Inc. Project: By: MCB Date: 7/12/23 Location: Checked: Date: BLDG TO CCB 9 BLDG TO CCB 11 BLDG TO CCB 19 Existing System C 0.90 0.90 0.90 0.65 I 7.44 7.44 7.44 7.44 A 0.11 0.05 0.08 0.79 Q 0.72 0.36 0.52 3.82 Rational Method Roof Drain System Calculations Proposed Restaurants South Windsor, CT Total Roof Runoff to Proposed Storm Drainage System (In Hydraflow Model) C E D A R A V E N U E B U C K L A N D R O A D COT T O N W O O D L A N E Existing Building MON. w/Disc MON. (Broken) Co n c . S i d e w a l k Co n c . S i d e w a l k Co n c . S i d e w a l k Con c . S i d e w a l k CCB T.G.=136± SILTED CCB T.G.=141.56 INV.=137.6(S) INV.=137.6(N) CCB T.G.=147.22 INV.=141.8(E) INV.=141.7(W) CCB T.G.=141.58 INV.=137.7(N) CCB T.G.=153.30 SILTED SNET 24S SNET 25S CL&P w/Riser 34161 SBC w/Riser 5277 Hand Hole (Traffic) Hand Hole (Traffic) Traffic Control Box Span Pole Electric Vault Electric Vault 6" 6"6" 6" 6" 30" SLCPP INV.=125.0 30" SLCPP INV.=123.0 30" SLCPP INV.=122.9 30" SLCPP INV.=125.0 Gr a s s Gr a s s N/F Evergreen Walk Lifestyle Center, LLC 4 5 ' Easement in favor of CL&P (See Survey Notes 4.D & 14) Easement In Favor of the Connecticut Water Company (See Survey Notes 4.B & 13) 20 ' Area of Dense Vegetation- Contours Depicted per GIS Unit 2 Drainge Easement in Favor of James & Jeanne H. Sabia (See Survey Note 5) 20' Easement to Slope in Favor of town of South Windsor (See Survey Notes 4.A & 11) Unit 12 "Costco" Head Wall Easement in favor of COXCOMM, INC. (See Survey Notes 4.E & 15) 18 " S L C P P 18 " S L C P P 42" S L C P P S SAN -MH T.F.=131.64 INV.=120.6(SW) INV.=120.6(NE) SAN MH T.F.=135.00 INV.=121.6(SW) INV.=121.6(NE) INV.=121.8(SE) SAN MH T.F.=137.12 INV.=122.2(SW) INV.=122.3(NE) INV.=122.3(W) S S S SAN MH T.F.=128.41 INV.=119.3(NE) INV.=119.3(S) INV.=119.3(NW) 10" P V C 10 " P V C 10 " P V C 10" P V C 8" P V C 10 " P V C Bit. Parking Ret a i n i n g W a l l Conc. Pad B-2 B-6 B-1 B-5 B-3 B-4 Tie - L i n e N5 ° 1 7 ' 2 9 " E - 1 4 1 . 1 9 ' 8" D u c t i l e I r o n W a t e r 12 " D u c t i l e I r o n W a t e r Bit. Parking Comm. Vault Comm. Vault 40' Limit of Developable Area Per Map Ref. in Survey Note 4.F Unit Li n e (Typ.) I.PIN 6" G a s 4" Ga s Area of Low Quality Wetlands (See Survey Note 4.F) Easement in favor of Connecticut Water Company (See S.W.L.R. Vol.1608 Pg.80 & Maps #3080, 3082) Easement in favor of Cox Business Services, LLC (See S.W.L.R. Vol.1632, Pg.252 & Map #3122) Easement In Favor of the Yankee Gas Services Company (See S.W.L.R. Map 4312) 8" Du c t i l e I r o n W a t e r T EV EV 133.174 134.681 136.013 154.5 154.5 MP E E E E E E E E E E E E E E E E E MP FF= 137.6 1 3 6 1 3 8 13 8 13 6 1 3 6 143 14 4 14 4 143 14 4 141 1 4 1 14 1 1 4 0 140 13 9 140 14 1 1 4 2 145 1 4 6 145 137.5 135.2 138.6 TC 143.7 HP 143.4 146.6 TC 147.1 144.2 HP 144.4 144.0 144.3 TC 145.1 BC 144.6 TC 145.1 BC 144.6 144.4 144.9 145.9 TC 145.9 BC 145.4 HP 145.4 145.2 141.5 141.8 142.8 144.5 140.4 140.6 141.1 142.4 140.5 140.4 140.9 141.0 140.5 140.6 139.6 146.2 146 14 6 1 3 9 1 4 0 1 4 1 1 4 2 1 4 3 1 4 4 14 5 14 1 139 138 13 7 1 3 6 1 3 7 1 3 8 139 1 3 9 13 8 13 7 1 3 8 139 140 141 1 4 2 14 1 14 3 145 144 14 5 14 5 145 136 13 5 1 3 4 1 3 3 135 134 TW 145.5 BW 145.0 13 7 146 145 144 143 142 TW 145.5 BW 141.5 TW 145.5 BW 140.5 TW 143.5 BW 139.0 TW 144.5 BW 140.0 TW 144.0 BW 138.5 TW 143.5 BW 138.5 TC 139.5 BC 139.0 14 3 142 141 140 139 TW 143.5 BW 139.0 TW 144.5 BW 139.0 TC 144.1 BC 143.6 TW 143.5 BW 139.5 TW 143.5 BW 143.0 TW 145.0 BW 143.0 TW 146.5 BW 143.0 1 3 7 H YD MP MP MP MPWV WV WV WV co wv wv wv HYD wv wv MP wv wv T T EV EV 136.013 MP DRI V E TH R U DO NOT EN T E R STOP STOP DIG I T A L PIC K U P AHE A D EV EV EV SHEET NAME DATE CB PROJECT NO. DESIGNED MCB SCALE DRAWN MCB CHECKED TD JULY 12, 2023 1"=30' DR A I N A G E A R E A M A P - S T O R M D R A I N A G E S Y S T E M SO U T H W I N D S O R , C O N N E C T I C U T PR O P O S E D R E S T A U R A N T S CE D A R A V E N U E A N D B U C K L A N D A V E N U E SHEET NO. 1 OF 1 DE S C R I P T I O N BY DA T E 0'15'30' 0 1/2"1" Copyright SLR International Corporation - 2023 S W N E 99 R E A L T Y D R I V E CH E S H I R E , C T 0 6 4 1 0 20 3 . 2 7 1 . 1 7 7 3 SL R C O N S U L T I N G . C O M 21167.00001