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20240313-NOI-Barnstable-607398 - Signed (1)
NOTICE OF INTENT Parking Area for Cape Cod Rail Trail Phase III (MassDOT Project #607398) 0 Mary Dunn Road Barnstable, Massachusetts PREPARED FOR Town of Barnstable Department of Public Works 382 Falmouth Road Hyannis, MA 02601 508.790.6400 ext. 4931 PREPARED BY 101 Walnut Street PO Box 9151 Watertown, MA 02471 617.924.1770 MARCH 2024 March 19, 2023 Ref: 12811.01 Barnstable Conservation Commission c/o Darcy Karle, Conservation Administrator 230 South Street, Hyannis MA 02601 ATTN: Chairman F.P. Tom Lee Re: Notice of Intent: Parking Area for Cape Cod Rail Trail Phase III (MassDOT Project #607398) 0 Mary Dunn Road, Barnstable, Massachusetts Dear Chairman Lee and Commission Members: On behalf of the Town of Barnstable Department of Public Works, (the Applicant) VHB, Inc. is submitting the attached Notice of Intent (NOI) for the proposed construction of a parking area on Mary Dunn Road (the Project) to provide access to the proposed Phase III of the Cape Cod Rail Trail Shared Use Path in Barnstable, Massachusetts. This NOI is being filed under the Massachusetts Wetlands Protection Act (MGL Chapter 131, Section 40) and its implementing regulations (310 CMR 10.00) and the Town of Barnstable Wetlands Protection Ordinance (the Ordinance) and its implementing regulations (Chapters 237 and 704). Proposed work consists of constructing a new 13 space paved parking area with associated access paths, gates, granite curbing, wooden railings, and new stormwater management features. The full scope of work is described in the attached NOI Narrative. Work will be required in the 100-foot buffer zone to Bank and BVW as detailed in the NOI Narrative. The Project has been designed to minimize impacts to wetland resources. Areas of temporary disturbance will be revegetated as part of the Project’s landscaping plan and native shrub and tree plantings are also proposed within the limits of the Project Site. No work is proposed within the 50-foot buffer zone established by the Ordinance. During construction, erosion controls will be installed to protect adjacent resources. In compliance with the WPA and the Ordinance, notification to abutters regarding this NOI will be made by certified return receipt mail upon receival of a meeting date. A copy of the certified list of abutters is enclosed as part of the NOI. As a municipally sponsored Project, the Town is not subject to filing fees. Barnstable Conservation Commission March 19, 2024 Page 2 Please advertise this matter for public hearing at the Commission’s next scheduled meeting. Should you have any questions concerning this submittal, or require additional information please contact me at 617.607.1019. Sincerely, Dan Cannata Environmental Scientist Attachment: Notice of Intent: Parking Area for Cape Cod Rail Trail Phase III (MassDOT Project #607398) Mary Dunn Road, Barnstable, Massachusetts CC: Barnstable Department of Public Works MassDOT Notice of Intent i Table of Contents Table of Contents Notice of Intent Forms Notice of Intent Figures Attachment A: Notice of Intent Narrative ........................................................................................... 1 Introduction ................................................................................................................................................................... 1 Site Description ............................................................................................................................................................ 2 Work Description ........................................................................................................................................................ 5 Mitigation Measures .................................................................................................................................................. 5 Regulatory Compliance ............................................................................................................................................ 7 Summary ......................................................................................................................................................................... 8 Attachment B: Abutter Information Attachment C: Existing Conditions Documentation Attachment D: Stormwater Management Memorandum Attachment E: Notice of Intent Plans Notice of Intent Notice of Intent Forms › WPA Form 3 › NOI Wetland Fee Transmittal Form › Chapter 707 Regulation Governing Minimum Submission Requirements for a Notice of Intent Application Checklist Chap 707/rev. March 2022 Page 1 CHAPTER 707 Regulation Governing Minimum Submission Requirements for a Notice of Intent Application The Barnstable Conservation Commission has adopted the following requirements in order to obtain more consistently complete submission documents necessary for a thorough and efficient review of all Notice of Intent (NOI) applications. Failure to complete any of the items in this checklist may result in your application being denied. Applicant or applicant’s agent should check each box denoting that the task has been completed or in certain instances, like field staking, denoting that the task will be completed. The following submission checklist covers the requirements of Chapter 237, Wetlands Protection, of the Part I General Ordinances of the Code of the Town of Barnstable. This checklist shall be submitted to the Barnstable Conservation Division with the NOI application. 1.Requirements a.The applicant understands, unless they’ve instructed otherwise, they are applying both under the Massachusetts Wetlands Protection Act M.G.L. c.131,§40 and Chapter 237 of the Town of Barnstable General Ordinances. b.Attach a written narrative to the NOI application (WPA Form 3), available at: www.mass.gov/eea/agencies/massdep/service/approvals/wpa-form-3.html describing any project impacts and proposed mitigation as they relate to the following: 1)Any of the interests of Chapter 237 of the General Ordinances and the MassDEP Wetlands Protection Act M.G.L. 131, §40. 2)The performance standards contained in the MassDEP Wetlands Protection Regulations (310 CMR 10.00) 3)Chapter 704: Regulation Governing Activity in the 100-ft. Buffer Zone. 4)Chapter 703: Private Docks and Piers. 5)Any other applicable regulations (310 CMR 10.00 or as promulgated under Chapter 237 of the General Ordinances). c.Enclose proper payment to cover the fee for Chapter 237 filings. Consult current Fee Schedule at www.townofbarnstable.us/Conservation d.Please indicate who is to record the Order of Conditions (check one): Applicant Agent 2.Abutter Notification (See Abutter Notification Regulation, Chapter 706) Town of Barnstable Conservation Commission 230 South Street Hyannis Massachusetts 02601 Office: 508-862-4093 E-mail: conservation@town.barnstable.ma.us X X N/A Fee Exempt- Municipal Project X X X X X Chap 707/rev. March 2022 Page 2 a.Contact the Conservation Division office at (508) 862-4093 regarding the docketing process, or see current schedule of Conservation Hearings and submission deadlines at: www.townofbarnstable.us/Conservation/ b.Provide a copy of the list of abutters within a 100 ft radius of the project parcel. c.Provide a copy of the Assessor’s Map indicating the parcel of the project site and showing the 100 ft radius of the project parcel. d.Provide a copy of the abutter notification letter. Use t he form letter provided in our Abutter Notification Regulation (Chapter 706), available on the Conservation Division website. e.Bring the green return receipts, from the certified mai lings to the abutters, as proof of notification to the public hearing. If any mailings are returned, bring the entire envelope, indicating by postal service stamp the reason for return. You will retain the receipts afterwards, not the Conservation Division. f.I further certify under the penalties of perjury that all abutte rs were notified of the Notice of Intent Application, pursuant to the requirements of Chapter 237 of the General Ordinances of the Code of the Town of Barnstable. Notice must be made in writing by certified mail to all abutters within 100 ft of the property line of the project location. _______________________________________ Signature of Applicant or Representative Date 3.Field Staking: a.On or before Tuesday, @ 8:30 a.m., one week prior to the scheduled public hearing, have your project staked by a professional engineer or registered land surveyor showing all outside corners of all proposed structures and the continuous proposed “limit of work” line. b.Have a wetland scientist or other qualified professional flag all wetland res ource areas on or within 100 ft of the work area. Make sure that the flags are sequentially numbered. c.Provide a project identification stake with bright painted top and applicant name and address, easily visible from the street approaching the site. 4.Legal Advertisement Fees: a.Conservation will submit the legal ad for publication in a local newspaper. The applicant or his/her agent is responsible for payment, by check (payable to the Town of Barnstable), at the hearing or by mail. The cost of the legal ad will be pre-calculated and posted on the hearing agenda prior to the hearing. 5.Minimum Documentation for a Complete Application: a.Provide a completely filled-out (in all parts) NOI application as locally adopted for the Town of Barnstable, including MassDEP Vegetated Wetland Field Data Form. Indicate Assessor’s map and parcel of the project, as well as the street or road address, and pertinent village (i.e., Hyannis, Centerville, Barnstable, etc). b.Provide two (2) original project plans, stamped in blue or red ink (wet stamp). Plans must be signed and dated by a Massachusetts licensed, professional engineer, land surveyor, architect or landscape architect (as applicable), and shall be drawn at a readable scale (1" = 20' preferred). For multi-acre sites, a second site plan, drawn at larger scale showing the entire site, should also be provided. X X X X X X X X X X 2/26/2023 Chap 707/rev. March 2022 Page 3 c.Provide a signed Permission to Access Property, Form PA. The form must be signed by the property Owner, or legal representative and submitted prior to NOI being docketed and application advertised. Form PA is available at www.townofbarnstable.us/Conservation/. Do not send the abutter letter out until the form is submitted to the Conservation Division office. d.For projects requiring mitigation plantings under Chapter 704 -3, 704-4, and 704-5, mitigation planting location(s) shall clearly be shown on landscaping planting plan. The planting plan shall include species list (chosen from the Town of Barnstable Conservation Commission approved planting lists), sizes, densities and/or quantities. The plan shall also provide area calculations between 0 to 50 and 50 to 100 separately for the amount of mitigation planting required, and the amount of mitigation planting proposed. e.Provide detailed, written street directions to the locus (site). f.Provide a copy of a U.S.G.S. locus map indicating the general area of the project site. g.Provide a check for the Town of Barnstable portion of the required filing fee. (The portion payable to the Commonwealth, see 7. e. below) h.Provide any other documentation, photographs, architectural renderings or other supporting data prepared by professionals competent in the field which may be relevant to the application. 6.The site plan shall also show: a.All existing and proposed contours at 2-ft. minimum intervals (1-ft. preferred). b.Clear delineation of all existing and proposed structures and features. Building structures must be accurately dimensioned (fixed location) from property lines and wetland resource a reas. Plans shall provide sufficient detail to show all potential wetland impacts, mitigation, compensatory areas, engineered structures, utilities, landscaping, etc. within the area of jurisdiction. On complicated sites, existing and proposed conditions must be shown on separate sheets. c.Locus inset map of the site clearly showing its location relative to surrounding public streets. d.All wetland resource area flags by individual flag number (matched to the field) to clearly identify all resource areas on or within 100 feet of the work area. The individual who performed the flagging and date of flagging shall be identified on the plan next to the resource line. e. Section views showing changes in grade, cuts and fills. 7.SUBMISSION OF THE COMPLETED APPLICATION WITH PLANS: a.Provide a signed Permission to Access Property, Form PA. The form must be signed by the property Owner, or legal representative and submitted prior to NOI being docketed and application advertised . Form PA is available at www.townofbarnstable.us/Conservation/. Do not send the abutter letter out until the form is submitted to the Conservation Division office. b.Email NOI application and all associated materials in PDF format to Kimberly.Cavanaugh@town.barnstable.ma.us AND Darcy.Karle@town.barnstable.ma.us . Do not include copies of checks. All attachments must be named with the hearing date (year first), type, name, address. Examples 20220301 NOI Smith 21 Main Street or 2022031 NOI Plan Smith 21 Main Street. c.Provide two (2) full NOI applications with folded plans (colored ink stamp) with signature/date to the Town of Barnstable Conservation Division Office for administrative use; X X X X X X X X X X Notice of Intent Notice of Intent Figures › Figure 1 – Site Location Map › Figure 2 – Aerial Map › Figure 3 – NHESP Map › Figure 4 – FEMA FIRM Map 6RXUFHV 9+%0DVV*,6 3DWK ??D]UJLVGV?JLVVKDUH?JLV?DUFJLVV\VWHP?DUFJLVLQSXW?12,)LJXUHV?12,([SRUW0DS*36HUYHU?H[WUDFWHG?S?QRLBWHPSODWH?12,B7HPSODWHDSU[ JPVD*,6 1 %DUQVWDEOH0$ &DSH&RG5DLO7UDLO3DUNLQJ/RW )LJXUH 86*66LWH/RFDWLRQ )HHW 3URMHFW$OLJQPHQW Project Limits %$5167$%/(0DU\'XQQ5RDG0LGFDSH+LJKZD\ ,QGHSHQGHQFH'UL Y H 6RXW K ) O L Q W 5 R F N 5 R D G (QRFK&REE : D \ 0LGFDSH+LJKZD\ ,QGHSHQGHQ F H ' U L Y H 6RXUFHV 9+%0DVV*,6 3DWK ??D]UJLVGV?JLVVKDUH?JLV?DUFJLVV\VWHP?DUFJLVLQSXW?12,)LJXUHV?12,([SRUW0DS*36HUYHU?H[WUDFWHG?S?QRLBWHPSODWH?12,B7HPSODWHDSU[ JPVD*,6 1 )LJXUH $HULDO2YHUYLHZ )HHW %DUQVWDEOH0$ &DSH&RG5DLO7UDLO3DUNLQJ/RW 3URMHFW$OLJQPHQW Project Limits 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 6RXUFHV 9+%0DVV*,6 3DWK ??D]UJLVGV?JLVVKDUH?JLV?DUFJLVV\VWHP?DUFJLVLQSXW?12,)LJXUHV?12,([SRUW0DS*36HUYHU?H[WUDFWHG?S?QRLBWHPSODWH?12,B7HPSODWHDSU[ JPVD*,6 1 )LJXUH 3ULRULW\+DELWDW )HHW 3URMHFW$OLJQPHQW 1+(63&HUWLILHG9HUQDO3RROV 1+(633ULRULW\+DELWDWVRI5DUH6SHFLHV 1+(633RWHQWLDO9HUQDO3RROV 1+(63(VWLPDWHG+DELWDWVRI5DUH:LOGOLIH 3URMHFW&RPPHQWV ILJXUHFRPPHQWV %DUQVWDEOH0$ &DSH&RG5DLO7UDLO3DUNLQJ/RW Project Limits 0DU\ 'XQQ5RDG(Q RFK & R E E : D \ 0LGFDSH +LJKZD\ ,QGHSHQGHQFH 'ULYH 6R X W K )OLQW 5 R F N 5 RDG 6RXUFHV 9+%0DVV*,6 3DWK ??D]UJLVGV?JLVVKDUH?JLV?DUFJLVV\VWHP?DUFJLVLQSXW?12,)LJXUHV?12,([SRUW0DS*36HUYHU?H[WUDFWHG?S?QRLBWHPSODWH?12,B7HPSODWHDSU[ JPVD*,6 1 )LJXUH )(0$)ORRGSODLQ )HHW 3URMHFW$OLJQPHQW 3URMHFW&RPPHQWV ILJXUHFRPPHQWV %DUQVWDEOH0$ &DSH&RG5DLO7UDLO3DUNLQJ/RW $UHDZLWKQR'),503DSHU),50VLQ(IIHFW $UHD1RW,QFOXGHG ; 5HGXFHG)ORRG5LVNGXHWR/HYHH ; 'UDLQDJH$UHD 6T0L ; $QQXDO&KDQFHRI)ORRGLQJ ' 3RVVLEOH%XW8QGHWHUPLQHG+D]DUG 9( +LJK5LVN&RDVWDO$UHD $2 $QQXDO&KDQFHRIIW6KHHW)ORZ)ORRGLQJZLWK'HSWK $+ $QQXDO&KDQFHRIIW3RQGLQJZLWK%)( $( 5HJXODWRU\)ORRGZD\ $( $QQXDO&KDQFHRI)ORRGLQJZLWK%)( $ $QQXDO&KDQFHRI)ORRGLQJQR%)( Project Limits Notice of Intent Attachment A: Notice of Intent Narrative › Introduction › Site Description › Work Description › Mitigation Measures › Regulatory Compliance › Summary Notice of Intent A-1 Attachment A: Notice of Intent Narrative Attachment A: Notice of Intent Narrative This Notice of Intent (NOI) is filed pursuant to the Massachusetts Wetlands Protection Act (WPA)(MGL Chapter 131, Section 40) and its implementing regulations (310 CMR 10.00) and Chapter 237: Wetlands Protection Ordinance of the Code of the Town of Barnstable (the Ordinance) and its implementing regulations (Chapters 237 and 704). Introduction The Town of Barnstable Department of Public Works (the Applicant) is proposing to construct a parking area (the Project) to serve users of the proposed Phase III of the Cape Cod Rail Trail (CCRT) shared-use path (SUP) Barnstable, MA (the Project Site). Work is proposed as part of the Massachusetts Department of Transportation (MassDOT) Transportation Improvement Program (TIP) for Fiscal Year 2023 (MassDOT Project #607398). The CCRT Phase III Project will run from Peter Homer Park in Yarmouth to a new trail head at Mary Dunn Road in Barnstable. No portion of the shared use path outside of the outer limits of the proposed parking area will be required in areas subject to the jurisdiction of the WPA or the Ordinance. The Project consists of constructing a new paved parking area with 13 parking spaces (including one accessible space) along the east side of Mary Dunn Road. Related work will include installing a wooden guardrail, granite curbing, pipe gates, a 5 foot wide concrete walkway on the south side of the parking area and pathways connecting to the proposed SUP. Stormwater improvements include a new catch basin structure, leaching basins and a hydrodynamic separator. Landscaping improvements within the parking area consist of native tree and shrub plantings. The proposed work will occur in the vicinity of Bordering Vegetated Wetland (BVW) and Land Under Waterbodies and Waterways (LUWW) considered jurisdictional areas as defined by the WPA and the Ordinance. The Project will occur within the outer limits of 100-foot buffer zone associated with Bank and BVW and will not result in any permanent or temporary impacts to adjacent wetland resource areas. No work is proposed within the 50-foot buffer zone established by the Ordinance. Wetland resource areas will be protected from impacts during construction through the implementation of an erosion and sedimentation control program. This program includes provisions to minimize areas of disturbance through phasing and sequencing, limit erosion through stabilization, and prevent sediment from leaving the site by installing structural controls. Runoff generated from the project will be collected and treated in accordance with design guidelines 1 developed by Department of Environmental Protection (DEP) and standards contained in the WPA Regulations. 1 DEP, 2008. Massachusetts Stormwater Handbook. Notice of Intent A-2 Attachment A: Notice of Intent Narrative Site Description The Project Site is located east of Mary Dunn Road (across from 895 Mary Dunn Road) adjacent to the paved roadway layout. The Project Site consists of a mix of sandy and gravel access road and gently sloped wooded areas dominated by pitch pine (Pinus rigida), northern red oak (Quercus rubra), and white oak (Quercus alba). The understory is dominated by a mix of shrubby and herbaceous plants including common serviceberry (Amelanchier arboria), greenbrier (Smilax rotundifolia), and lowbush blueberry (Vaccinium angustifolium). East of the Project Site is a moderately sloped wooded area at the bottom of which is a Bordering Vegetated Wetland (BVW) along Israel Pond’s western edge. South of the Project Site the BVW extends west from Israel Pond in a distinct linear configuration towards Mary Dunn Road. A portion of the Project Site is within the Hyannis Ponds Wildlife Management Area (WMA). The WMA totals 365 acres in size and covers much of the area east of the Project Site as well as a small portion of land on the west side of Mary Dunn Road adjacent to the Project Site. Present within the Project Site is a guard rail set back from Mary Dunn Road and a small parking area. Just north of the parking area is a gated access road to the WMA. According to the regional Natural Resources Conservation Service 2 soil survey, the majority of the surrounding area has been mapped as Carver loamy coarse sand, 3 to 8 percent slopes, with a small section in the northern portion of the Project Site mapped as Plymouth-Barnstable complex, hilly, very bouldery. According to the most recently available data provided by the Massachusetts Natural Heritage and Endangered Species Program 3 (NHESP), a portion of the Project Site is within Priority Habitat of Rare Species and Estimated Habitat of Rare Wildlife. There are no Certified or Potential Vernal Pools on the Project Site, nor is any portion of the Project Site within an Area of Critical Environmental Concern (ACEC). According to the Massachusetts Department of Environmental Protection (DEP), the Project Site is not located in an area designated as an Outstanding Resource Water 4. No portion of the Project Site is located within a Zone II Interim Wellhead Protection Area 5. The most recently issued Flood Insurance Rate Map (FIRM)6 for the area, produced by the Federal Emergency Management Agency (FEMA), indicates that no portion of the Project Site is within mapped floodplain for the 100-year storm event.7 Wetland resource areas on/near the site are described below. Wetland Resource Areas Wetlands in the vicinity of the Project Site were delineated on October 7, 2022, by environmental scientists with VHB in accordance with methods developed by the DEP 8 and the U.S. Army Corps of 2 Soil Survey Staff, Natural Resources Conservation Service, United States Department of Agriculture. Web Soil Survey. 3 NHESP, 2021. Massachusetts Natural Heritage Atlas. 15th Edition. 4 DEP, 2010. Designated Outstanding Resource Waters of Massachusetts. 5 DEP, 2012. Approved Wellhead Protection Areas (Zone II). 6 Federal Emergency Management Agency, National Hazard Flood Layer, Digital Flood Insurance Rate Map (DFIRM). 7 DEP, 2021. MassGIS Data: MassDEP Wellhead Protection Areas (Zone II, Zone I, IWPA) 8 DEP, 1995. Delineating Bordering Vegetated Wetlands Under the Massachusetts Wetlands Protection Act. Notice of Intent A-3 Attachment A: Notice of Intent Narrative Engineers.9 The following sections of this narrative describe the wetlands and identify resource areas that are regulated under the WPA Regulations and the Ordinance. The state-regulated wetland resource areas identified in the vicinity of the Project Site are regulated as Bank, BVW and LUWW. These resource areas are defined under the WPA Regulations (310 CMR 10.00) as follows: Bank: As defined at 310 CMR 10.54 (2), a Bank is the portion of the land surface, which normally abuts and confines a water body. The upper boundary of Bank is the first observable break in slope. Bordering Vegetated Wetlands (BVW): As defined by 310 CMR 10.55(2)(a) and (c), BVWs are “freshwater wetlands that border on creeks, rivers, streams, ponds, and lakes.” The boundary of BVW is determined by the presence of 50 percent or more of wetland indicator plants and saturated or inundated conditions. Land Under Waterbodies and Waterways (LUWW): As defined at 310 CMR 10.56 (2), LUWW is “the bottom of, or land under, the surface of the ocean or any estuary, creek, river, stream, pond, or lake.” The Ordinance also establishes jurisdiction over vegetated wetlands which are defined as “any area of at least 500 square feet where surface or ground water, or ice, at or near the surface of the ground support a plant community dominated (at least 50%) by wetland species. Wetlands adjacent to the Project Site are summarized in Table 1 below and are described in more detail in the following sections of this attachment. Table 1: Wetland Resource Areas Wetland Flag Numbers Type Description Israel Pond BF1-100 to BF1-104 Bank, LUWW Open water pond Wetland 1 WF1-105 to WF1-120 BVW PEM/PSS Wetland bordering the North/West Sides of Israel Pond. Source: VHB 2023 9 USACE, 2012. Regional Supplement to the Corps of Engineers Wetland Delineation Manual: Northcentral and Northeast Region, Version 2.0. Notice of Intent A-4 Attachment A: Notice of Intent Narrative Israel Pond Israel Pond is a shallow coastal plain pond approximately 8 acres in size. The pond water level was very low at the time of delineation due to the drought conditions of 2022. Surrounding the pond is upland and wetland areas contained within the Hyannis Ponds Wildlife Management Area. Dominant species along the banks include sweet pepperbush (Clethra alnifolia), devils beggartick (Bidens frondosa), Woolgrass (Scirpus cyperinus), buttonbush (Cephalanthus occidentalis), and Beach Heather (Hudsonia tomentosa). It is likely that one or more rare species are located within the pond. A portion of the southwest side of the pond was delineated with blue flags BF1-100 to BF1-104. The WPA establishes a 100-foot Buffer Zone that extends from the limits of Bank associated with Israel Pond. The Ordinance establishes a 50-foot buffer zone and a 50-to-100-foot buffer zone which extend from the limits of Bank. Wetland 1 A PSS/PEM borders Israel Pond’s west and northwest edge most proximate to the Project Site. A narrow finger-like projection receiving drainage from Mary Dunn Road extends from the roadway shoulder to Israel Pond. The upland areas surrounding the BVW are moderately sloped wooded areas dominated by pitch pine (and northern red oak (Quercus rubra). Dominant vegetation in the BVW includes sweet pepperbush , Woolgrass , buttonbush, and Beach Heather . The BVW was delineated with pink flags WF1-105 to WF1-120. The WPA establishes a 100-foot Buffer Zone that extends from the limits of BVW associated with Wetland 1. The Ordinance establishes a 50-foot buffer zone and a 50 to 100-foot buffer zone which extend from the limits of Wetland 1. Buffer Zone The WPA establishes a 100-foot buffer zone from the limits of Bank and BVW associated with Israel Pond and Wetland 1 described above. The Buffer zone within the Project Site currently consists of gravel parking and access roads as well as wooded areas dominated by pitch pine and oak along the east side of Mary Dunn Road. Additionally, the Commission has established in its Performance Standards for Projects Requiring a Notice of Intent (704-3A) that a 50 ft undisturbed buffer zone shall be retained between the landward- most wetland resource areas and the limit of proposed site disturbance. A 50-foot buffer zone associated with Wetland 1 extends near to the Project Site. The 50-foot Buffer Zone consists of wooded areas between the proposed limits of the parking area and wetland areas associated with Israel Pond. No work is proposed within the 50-foot Buffer Zone as a part of the Project. The Commission also regulates a 50 to 100 ft buffer zone which is defined as the area of land extending 50 ft horizontally outward from the boundary of the 50 ft buffer zone and terminating at the outer edge of the Commission’s 100 ft jurisdictional zone. The 50 to 100-foot buffer zone extends from the boundary of Wetland 1 in the Project Site. The 50 to 100 ft buffer zone is coincident with the limits of the 100-foot buffer zone and consists of wooded areas and gravel access roads and parking areas adjacent Mary Dunn Road. Notice of Intent A-5 Attachment A: Notice of Intent Narrative Work Description The Project consists of constructing a new parking area east of Mary Dunn Road to provide access to Phase III of the CCRT. Although methodology and construction sequencing will be determined by the Project’s contractor, work will generally consist of the following: Prior to construction, erosion and sedimentation controls will be installed along the limits of work and clearing and grubbing of the Project Site will occur. A new full depth pavement parking area will be constructed in the Project Site which will provide a connection to the proposed SUP to the north. A 5-foot wide concrete walkway will be constructed on the south side of the parking area and provide connection to Mary Dunn Road. Wooden guardrail and granite curbing will be installed along the edges of parking spaces. Pipe gates will be installed at access points to the SUP. Stormwater features proposed for the Project include three new leaching basins in the eastern portion of the Site and a new hooded deep sump catch basin which will be installed near the entrance to the parking area on Mary Dunn Road. Native landscape plantings are proposed within portions of the Project Limits. Work in the 100-foot buffer zone is described below. This work fully complies with all applicable requirements of the WPA and the Ordinance as demonstrated in the Regulatory Compliance section of this Narrative. Work in Buffer Zone As described above, the Project will require unavoidable work within the outer 50 feet of the 100-foot Buffer Zone associated with Wetland 1. Work in the Buffer Zone consists of a small area of full depth pavement construction of the new parking area and concrete walkway, installing three leaching basins and a hydrodynamic separator. Associated work includes limited clearing and grubbing, installing erosion controls near wetland resource areas and installing wooden railings. As described above, no work is proposed within the locally established 50-foot buffer zone associated with Israel Pond or Wetland 1. Mitigation Measures A suite of mitigation measures is proposed to prevent short- and long-term impacts to wetland resource areas. Mitigation measures proposed for this project include both structural and non- structural practices as described below. Erosion and Sediment Control An erosion and sedimentation control program will be implemented to minimize temporary impacts to wetland resource areas during the construction phase of the project. The program incorporates Notice of Intent A-6 Attachment A: Notice of Intent Narrative Best Management Practices (BMPs) specified in guidelines developed by the DEP 10 and the U.S. Environmental Protection Agency (EPA)11. Proper implementation of the erosion and sedimentation control program will: › minimize exposed soil areas through sequencing and temporary stabilization; › place structures to manage stormwater runoff and erosion; and › establish a permanent vegetative cover or other forms of stabilization as soon as practicable. The following sections describe the controls that will be used and practices that will be followed during construction. These practices comply with criteria contained in the NPDES General Permit for Discharges from Large and Small Construction Activities issued by the EPA. Non-structural Practices Non-structural practices to be used during construction include, temporary seeding, permanent seeding, and pavement sweeping. These practices will be initiated as soon as practicable in appropriate areas at the site. Temporary and Permanent Seeding If conditions allow, a temporary vegetative cover will be established on areas of exposed soils during construction. Upon completion of final grading, any areas not covered by pavement, other forms of stabilization, or other methods of landscaping will be seeded with a native seed mix (per MassDOT Specification #765.635). The mix will be applied at the rate suggested by its manufacturer. Structural Practices Structural erosion and sedimentation controls to be used on the site include barriers and catch basin inlet protection. Erosion Control Barriers Prior to any ground disturbance, an approved erosion control barrier (per MassDOT Specification #767.121) will be installed at the downgradient limit of work. As construction progresses, additional barriers will be installed around the base of stockpiles and other erosion-prone areas. If sediment has accumulated to a depth that impairs proper functioning of the barrier, it will be removed by hand or by machinery operating upslope of the barriers. This material will be either reused at the Site or disposed of legally at a suitable offsite location. Any damaged sections of the barrier will be repaired or replaced immediately upon discovery. 10 DEP, 1997. Massachusetts Erosion and Sediment Control Guidelines for Urban and Suburban Areas: A Guide for Planners, Designers, and Municipal Officials. 11 EPA, 2007. Interim Developing Your Stormwater Pollution Prevention Plan: A Guide for Construction Sites. Office of Water. Report EPA 833- R-060-04. Notice of Intent A-7 Attachment A: Notice of Intent Narrative Catch Basin Inlet Protection The inlets of existing and proposed catch basins will be protected from sediment inflow during the work period by surrounding them with a barrier of staked straw bales or by installing other barrier methods determined by the contractor. Stormwater Management Runoff generated from impervious surfaces will be collected and managed in accordance with the DEP policy. A stormwater management system will be constructed that includes measures to provide groundwater recharge, attenuate peak flows and provide water quality treatment. Compliance with the 10 stormwater management standards is addressed in the accompanying Stormwater Management Memorandum (See Attachment D). Regulatory Compliance As described above, the Project will require work within the 100-foot buffer zone established by the WPA and the 50–100-foot buffer established by the ordinance. As described in the Mitigation Measures section of this narrative, the Project includes provisions to minimize short and long-term impacts to adjacent wetlands. Work in Buffer Zone As identified in 310 CMR 10.53(1) of the WPA regulations, “the issuing authority should consider the characteristics of the buffer zone, such as the presence of steep slopes, that may increase the potential for adverse impacts on resource areas. Conditions may include limitations on the scope and location of work in the buffer zone as necessary to avoid alteration of resource areas. The issuing authority may require erosion and sedimentation controls during construction, a clear limit of work, and the preservation of natural vegetation adjacent to the resource area and/or other measures commensurate with the scope and location of the work within the buffer zone to protect the interests of the Act.” The proposed Project has been designed to address these requirements. As identified in the Mitigation Measures section of this attachment, an erosion and sedimentation control program will be implemented to prevent adverse impacts during construction. Portions of the buffer zone will be revegetated with native seed mix as well as tree and shrub plantings. As discussed above, no work is proposed in the inner 50-foot Buffer zone established by the Ordinance and therefore the Project complies with the performance Standard established at 704-3A: A 50 ft undisturbed buffer zone shall be retained between the landward-most wetland resource areas and the limit of proposed site disturbance. Work will be required in the 50–100-foot buffer zone which is coincident with the buffer zone established by the WPA. In addition to the parking area, native shrub plantings and drainage improvements are proposed within the 50-100-foot buffer to provide wildlife habitat and improved stormwater treatment. Details of the proposed plantings, including species, planting schedule and layout are shown on the accompanying Project Plans. Notice of Intent A-8 Attachment A: Notice of Intent Narrative Work in Priority Habitat As noted above, the Project limits are within Priority Habitat of Rare Species as determined by NHESP. Review of the Project pursuant to the Massachusetts Endangered Species Act (MESA) is being conducted under separate coordination with NHESP. Summary The Town of Barnstable Department of Public Works is proposing to construct a new parking area for users of the proposed CCRT Phase III SUP in Barnstable, MA. Work associated with the Project consists of constructing a new paved parking area on the east side of Mary Dunn Road and associated features including guardrail and stormwater upgrades. Work will be required within the 100-foot buffer zone established by the WPA and the Ordinance. No work is proposed within the 50-foot buffer zone, established by the Ordinance. No permanent impacts to wetland resource areas are proposed. Erosion and sedimentation controls will be employed throughout construction to prevent any secondary impacts to resource areas. The Applicant respectfully requests that the Barnstable Conservation Commission find these measures adequately protective of the interests identified in the WPA and the Ordinance and issue an Order of Conditions approving the work described in this NOI and shown on the accompanying plans. Notice of Intent Attachment B: Abutter Information › Notice to Abutters › List of Abutters NOTICE OF INTENT ABUTTER NOTIFICATION LETTER DATE: RE: Upcoming Barnstable Conservation Commission Public Hearing To Whom It May Concern, As an abutter within 100 feet of a proposed project, please be advised that a NOTICE OF INTENT application has been filed with the Barnstable Conservation Commission. APPLICANT: PROJECT ADDRESS OR LOCATION: ASSESSOR’S MAP & PARCEL: MAP PARCEL PROJECT DESCRIPTION: ________________________________________________________ APPLICANT’S AGENT: PUBLIC HEARING: WILL BE HELD REMOTELY VIA ZOOM See agenda posting on Town Clerks website available at least 48 hours in advance of the meeting for details. DATE: / / TIME: P.M. NOTE: Plans and applications describing the proposed activity are on file with the Conservation Commission at https://itlaserfiche.town.barnstable.ma.us/WebLink/Browse.aspx?id=825530&dbid=0&repo=TownOfBarns table, by email to Kimberly.Cavanaugh@town.barnstable.ma.us or by calling (508-862-4093) 3/19/2024 Town of Barnstable- DPW 0 Mary Dunn Road 347002001 The Town of Barnstable Department of Public Works, (the Applicant) is proposing construction of a parking area on Mary Dunn Road (the Project) to provide access to the proposed Phase III of the Cape Cod Rail Trail Shared Use Path in Barnstable, Massachusetts. Dan Cannata- VHB dcannata@vhb.com 1-617-607-1019 4 2 2024 6:30 6,060.00 Conservation Notice of Intent (NOI) Abutter Map for Subject Parcel 347002001 This map is for illustration purposes only. It is not adequate for legal boundary determination or regulatory interpretation. This map does not represent an on-the-ground survey. It may be generalized, may not reflect current conditions, and may contain cartographic errors or omissions. Legend Property owners within 100 feet of the perimeter of the subject parcel upon which work is proposed. Parcel lines shown on this map are only graphic representations of Assessor’s tax parcels. They are not true property boundaries and do not represent accurate relationships to physical objects on the map such as building locations. 253 Town of Barnstable GIS Unit 505 6/14/2023 gis@town.barnstable.ma.us Printed on: 0 ft.505 Subject Parcel Abutters 100 ft. Buffer ft. 1 inch = approx. Parcels Town Boundary Railroad Tracks Roads Paved Road Unpaved Road Bridge Paved Median Water Bodies Conservation Notice of Intent (NOI) Abutter List for Subject Parcel 347002001 Property owners within 100 feet of the perimeter of the subject parcel upon which work is proposed. Parcel ID Owner 1 Owner 2 Address Line 1 Address Line 2 City State Zip 329003 BARNSTABLE, TOWN OF (ARP)BARNSTABLE MUNICIPAL AIRPORT 480 BARNSTABLE RD 2ND FL HYANNIS 02601MA 331003X01 BARNSTABLE, TOWN OF (BRNWATER) 367 MAIN STREET HYANNIS 02601MA 331003X02 BARNSTABLE, TOWN OF (BRNWATER) 367 MAIN STREET HYANNIS 02601MA 331007 MASSACHUSETTS, COMMONWEALTH OF DIV OF FISHERIES & WILDLIFE 100 CAMBRIDGE STREET BOSTON 02114-2509MA 332005 COBB TRUST C/O BARNSTABLE, TOWN OF (MUN)367 MAIN STREET HYANNIS 02601MA 332009 BARNSTABLE, TOWN OF (BRNWATER) 367 MAIN STREET HYANNIS 02601MA 332011 TRINITY CHRISTIAN ACADEMY OF CC,INC 12 CARTER RD SOUTH YARMOUTH 02664MA 332012 BRAZILIAN ASSEMBLY OF GOD IN HYANNIS 959 MARY DUNN ROAD HYANNIS 02601MA 332013 INDEPENDENCE PLACE, LLC 1436 IYANNOUGH RD, SUITE 4 HYANNIS 02601MA 332014 NAUSET, INC C/O CAPEABILITIES INC 895 MARY DUNN RD HYANNIS 02601MA 332015 MASSACHUSETTS, COMMONWEALTH OF DIV OF FISHERIES & WILDLIFE 100 CAMBRIDGE STREET BOSTON 02202MA 333010 MASSACHUSETTS, COMMONWEALTH OF DIV OF FISHERIES & WILDLIFE 100 CAMBRIDGE STREET BOSTON 02202MA 346002 BARNSTABLE, TOWN OF (ARP)BARNSTABLE MUNICIPAL AIRPORT 480 BARNSTABLE RD, 2ND FLR HYANNIS 02601MA 6/14/2023 3:58 PMReport Generated On:Page 1 of 2 17Total Number of Abutters: This list by itself does NOT constitute a "Certified List of Abutters" and is provided only as an aid to the determination of abutters. If a Certified Abutter List is required, you must contact the Assessing Division to have this list certified. Parcel ID Owner 1 Owner 2 Address Line 1 Address Line 2 City State Zip 346002 BARNSTABLE, TOWN OF (ARP)BARNSTABLE MUNICIPAL AIRPORT 480 BARNSTABLE RD, 2ND FLR HYANNIS 02601MA 347001 YARMOUTH CAMP GROUND ASSOCIATION, INC C/O ERIKSON, LEE W 455 QUINAPOXET ST JEFFERSON 01522-1461MA 347002001 MASSACHUSETTS, COMMONWEALTH OF DIV OF FISHERIES & WILDLIFE 100 CAMBRIDGE STREET BOSTON 02114-2509MA 348016 MASSACHUSETTS, COMMONWEALTH OF DIV OF FISHERIES & WILDLIFE 100 CAMBRIDGE STREET BOSTON 02202MA 348036 COBB TRUST C/O TOWN OF BARNSTABLE (MUN)367 MAIN STREET HYANNIS 02601MA 6/14/2023 3:58 PMReport Generated On:Page 2 of 2 17Total Number of Abutters: This list by itself does NOT constitute a "Certified List of Abutters" and is provided only as an aid to the determination of abutters. If a Certified Abutter List is required, you must contact the Assessing Division to have this list certified. Notice of Intent B-1 Attachment B: Abutter Information Notice of Intent Attachment C: Existing Conditions Documentation › BVW Field Data Forms › Site Photos DEP Bordering Vegetated Wetland (310 CMR 10.55) Delineation Field Data Form Applicant:Town of Barnstable Prepared by:VHB, Inc.Project location:Mary Dunn Rd DEP File #: Check all that apply:Vegetation alone presumed adequate to delineate BVW boundary: fill out Section I only Vegetation and other indicators of hydrology used to delineate BVW boundary: fill out Sections I and IIMethod other than dominance test used (attach additional information) Section I. Vegetation Observation Plot Number:WF1-113 Transect Number:Upgradient Date of Delineation:7-Oct-22 Sample Layer and Plant Species Scientific name % Cover % Dominance Dominant Plant (yes or no) Wetland Indicator Category* Tree Layer Pitch Pine Pinus rigida 38.0%39.6%yes FACU Northern Red Oak Quercus rubra 38.0%39.6%yes FACU White Oak Quercus alba 20.0%20.8%yes FACU Sapling/Shrub Layer 20.0%37.7%yes FACU 10.0%18.9%yes FACU 10.0%18.9%yes FACW* 10.0%18.9%yes FAC* 3.0%5.7%no FAC* Common Serviceberry Northern Red Oak Highbush Blueberry Northern Bayberry Sweet Pepperbush Climbing Woody Vine Greenbrier 38.0%79.2%yes FAC* Poison Ivy 10.0%20.8%yes FAC* Ground Cover Lowbush Blueberry 63.0%86.3%yes FACU Wild Raisin Amelanchier arboria Quercus rubra Vaccinium corymbosum Morella pensylvanica Clethra alnifolia Smilax rotundifolia Toxicodendron radicans Vaccinium angustifolium Viburnum Cassinoides 10.0%13.7%no FACW* Remarks: Morphological Adaptations:0 Description:Moderately sloped wooded area between Mary Dunn Road and Isreal Pond. Dominated by Pitch Pine and Northern Red Oak *An asterisk after indicator status denotes wetlands plants: plants listed in the Wetlands Protection Act (MGL c.131, s.40); plants in the genus Sphagnum; or plants listed as FAC, FAC+, FACW-, FACW, FACW+, or OBL. Vegetation conclusion: Number of dominant wetland indicator plants: 3 Number of dominant non-wetland indicator plants: 7 Is the number of dominant wetland plants equal to or greater than the number of dominant non-wetland plants? no If vegetation alone is presumes adequate to delineate the BVW boundary, submit this form with the Request for Determination of Applicability or Notice of Intent.MA DEP; 3/95 Section II. Indicators of Hydrology Other Indicators of Hydrology: (check all that apply and describe) Site inundated: Hydric Soil Interpretation Depth to free water in observation hole: 1.Soil Survey Depth to soil saturation in observation hole: Is there a published soil survey for this site?yes no title/date:Soil Survey of Barnstable County - 1993 Water marks: map number:MA001 soil type mapped:Carver loamy coarse sand, 3 to 8 percent slopes Drift Lines: hydric soil inclusions:No Sediment deposits: Are field observations consistent with soil survey?yes no Remarks:Drainage patterns in BVW: Oxidized rhizoshperes: Water-stained leaves: 2.Soil Description Horizon Depth (inches)Matrix Color Mottles Color or Texture Recorded data (stream, lake, or tidal gauge; aerial photo; other): 1-3 10YR 4/2 Fine Sand 3+10YR 6/4 Fine Sand Other: Vegetation and Hydrology Conclusion for Upgradient of WF1-113 yes no Number of wetland indicator plants Remarks:>= number of non-wetland plants X Wetland hydrology present: hydric soils present X 3.Other:other indicators of hydrology present X Sample location is in a BVW X Conclusion: Is soil hydric?yes no Submit this form with the Request for Determination of Applicability or Notice of Intent DEP Bordering Vegetated Wetland (310 CMR 10.55) Delineation Field Data Form Applicant:Town of Barnstable Prepared by:VHB, Inc.Project location:Mary Dunn Rd DEP File #: Check all that apply:Vegetation alone presumed adequate to delineate BVW boundary: fill out Section I only Vegetation and other indicators of hydrology used to delineate BVW boundary: fill out Sections I and IIMethod other than dominance test used (attach additional information) Section I. Vegetation Observation Plot Number:WF1-113 Transect Number:Downgradient Date of Delineation:7-Oct-22 Sample Layer and Plant Species Scientific name % Cover % Dominance Dominant Plant (yes or no) Wetland Indicator Category* Tree Layer Sapling/Shrub Layer Buttonbush Cephalanthus occidentalis 38.0%35.8%yes OBL* Sweet Pepperbush 38.0%35.8%yes FAC* Beach Heather 20.0%18.9%yes N/A Long-beaked Willow Clethra Hudsonia tomentosa Salix bebbiana 10.0%9.4%no FACW Climbing Woody Vine Ground Cover Devils beggartick 63.0%50.8%yes FACW* Woolgrass 38.0%30.6%yes FACW* Soft Rush 10.0%8.1%no FACW* Reed Canary Grass 10.0%8.1%no FACW* Flat-top Goldenrod Bidens frondosa Scirpus cyperinus Juncus effusus Phalaris arundinacea Euthamia graminifolia 3.0%2.4%no FAC* Remarks: Morphological Adaptations:0 Description:PSS/PEM bordering Isreal Pond. A finger receiving drainage from Mary Dunn Rd extends towards the road. *An asterisk after indicator status denotes wetlands plants: plants listed in the Wetlands Protection Act (MGL c.131, s.40); plants in the genus Sphagnum; or plants listed as FAC, FAC+, FACW-, FACW, FACW+, or OBL. Vegetation conclusion: Number of dominant wetland indicator plants: 4 Number of dominant non-wetland indicator plants: 0 Is the number of dominant wetland plants equal to or greater than the number of dominant non-wetland plants? yes If vegetation alone is presumes adequate to delineate the BVW boundary, submit this form with the Request for Determination of Applicability or Notice of Intent.MA DEP; 3/95 alnifolia Section II. Indicators of Hydrology Other Indicators of Hydrology: (check all that apply and describe) Site inundated: Hydric Soil Interpretation Depth to free water in observation hole: 1.Soil Survey Depth to soil saturation in observation hole: Is there a published soil survey for this site?yes no title/date:Soil Survey of Barnstable County - 1993 Water marks: map number:MA001 soil type mapped:Carver loamy coarse sand, 3 to 8 percent slopes Drift Lines: hydric soil inclusions:yes Sediment deposits: Are field observations consistent with soil survey?yes no Remarks:Drainage patterns in BVW: Oxidized rhizoshperes: Water-stained leaves: 2.Soil Description Horizon Depth (inches)Matrix Color Mottles Color or Texture Recorded data (stream, lake, or tidal gauge; aerial photo; other): 0-2 10YR 2/2 Fine Sandy Loam 2-6 10YR 5/2 10YR 5/6 5%; FSL 6-12+10YR 2/1 Sandy Loam Other: Vegetation and Hydrology Conclusion for Downgradient of WF1-113 yes no Number of wetland indicator plants Remarks:Depleted matrix >= number of non-wetland plants X Wetland hydrology present: hydric soils present X 3.Other:other indicators of hydrology present X Sample location is in a BVW X Conclusion: Is soil hydric?yes no Submit this form with the Request for Determination of Applicability or Notice of Intent Parking Area for Cape Cod Rail Trail Phase III (MassDOT Project #607398) Mary Dunn Road, Barnstable, Massachusetts © VHB NOI Photography Log MassDOT PROJECT NUMBER 609067 CLIENT Town of Barnstable- Department of Public Works 382 Falmouth Road Hyannis, MA 02601 LOCATION Mary Dunn Road Barnstable, MA Parking Area for Cape Cod Rail Trail Phase III (MassDOT Project #607398) Mary Dunn Road, Barnstable, Massachusetts NO. 1 / 10.7.2023 DESCRIPTION Typical view of Israel Pond and Associated BVW near the Project Site. Work is proposed in the 100-foot Buffer Zone associated with Bank and BVW. No work is proposed within wetland resource areas. NO. 2 / 10.14.2016 DESCRIPTION View of access point to Wildlife Management Area on Mary Dunn Road. Slopes adjacent to proposed parking areas are moderately steep and primarily wooded. No work is proposed within 50 feet of resource areas. Parking Area for Cape Cod Rail Trail Phase III (MassDOT Project #607398) Mary Dunn Road, Barnstable, Massachusetts NO. 3 / 10.14.2016 DESCRIPTION View of access point off Mary Dunn Road. Notice of Intent Attachment D: Stormwater Management Memorandum \\vhb\gbl\proj\Wat-TE\12811.01\docs\memos\Stormwater Memo\12811.01 - Stormwater Memo.docx 101 Walnut Street Watertown, MA 02472-4026 P 617.924.1770 This Stormwater Management Memorandum has been prepared to show compliance with the Massachusetts Stormwater Management Standards to the maximum extent practicable, in accordance with the Massachusetts Wetlands Protection Act (WPA) Regulations (310 CMR 10.00). Project Description The Applicant, Town of Barnstable Department of Public Works, is proposing to construct a parking lot to serve the users of the proposed Phase III of the Cape Cod Rail Trail shared -use path (SUP) off Mary Dunn Road in Barnstable, Massachusetts (the Project), refer to Figure 1. Work is proposed as part of the Massachusetts Department of Transportation (MassDOT) Transportation Improvement Program (TIP) for Fiscal Year 2023 (MassDOT Project #607398). The Mary Dunn Road parking lot is a portion of a greater project that extends from Barnstable to Yarmouth. The Mary Dunn parking lot portion of the Project is within the 100-foot Buffer Zone to a Bordering Vegetated Wetland (BVW) adjacent to Israel Pond, which is subject to the jurisdiction of the Massachusetts Wetland Protections Act. The Project Area is within the Zone II wellhead protection area which is considered a critical area per 310 CMR 10.04. The remainder of the Cape Cod Rail Trail is not located within jurisdictional areas. The Project is considered a new development and is designed to fully comply with all ten Stormwater Management Standards. Site Description Watershed The Project Area lies within the Lewis Bay watershed which is covered by a Final TMDL for Total Nitrogen (CN 314) and within the greater Cape Cod Watershed which is covered by a Final TMDL for Pathogens (CN252.0). The Final TMDL implementation plan for stormwater management recommends starting with non -structural best management practices (BMPs), and supplementing with structural BMPs as necessary to address water quality requirements. To: Town of Barnstable Conservation Commission Date: March 19, 2024 Project #: 12811.01 Parking Area for Cape Cod Rail Trail Phase III Mary Dunn Road Barnstable, MA From: Eric Monkiewicz, PE Re: Stormwater Management Memorandum Ref: 12811.01 March 19, 2024 Page 2 \\vhb\gbl\proj\Wat-TE\12811.01\docs\memos\Stormwater Memo\12811.01 - Stormwater Memo.docx Land Use Land uses adjacent to the Project Area are primarily forest and grassland1. There are no known land uses with higher potential pollutant loads (LUHPPLs) in or with drainage areas directly tributary to the Project Area. Utilities Subsurface utilities include water, gas, and drainage. There are no utility poles and overhead wires within the Project Area. Topography The Project Area consists of mostly uneven wooded areas with hills and valleys. Mary Dunn Road runs north to south at about a 4% slope. Soils The Natural Resources Conservation Service (NRCS) Web Soil Survey2 has mapped the surface soils within the Project Area as primarily Plymouth-Barnstable complex, hilly, very bouldery (HSG A). A test pit conducted in 2017 indicated that parent soil in the area consists of sand. The test pit was conducted outside of the proposed leaching basin footprint due to access limitations through the woods. Estimated seasonal high groundwater (ESHGW) was not observed in the test pit. Based on proximity to Israel Pond, the SHGW is assumed t o be around the water elevation of the pond which is approximately El. 26. A map of existing NRCS Web Soil Survey in the Project Area and test pit results are included in Attachment B. Floodplain Portions of the Project Area are located in a Zone X which is identified as an area of minimal flood hazard, as shown on the Flood Insurance Rate Map (FIRM) panels 25001C 0567 J with effective date July 16, 2014, included in Figure 3. Existing Drainage Infrastructure There is existing drainage infrastructure within Mary Dunn Road consisting of catch basins and leaching basins. There is no existing drainage infrastructure where the proposed parking lot is located. Proposed Drainage Conditions Land Cover The Project proposes to increase impervious cover by approximately 0.26 acres. Proposed impervious cover will be comprised of the parking lot, sidewalk within the parking lot and shared-use path. Structural BMPs 1 MassGIS Land Cover Land Use 2016. https://maps.massgis.digital.mass.gov/MassMapper/MassMapper.html Accessed June 2023. 2 Soil Survey Staff, Natural Resources Conservation Service, United States Department of Agriculture. Web Soil Survey. Ref: 12811.01 March 19, 2024 Page 3 \\vhb\gbl\proj\Wat-TE\12811.01\docs\memos\Stormwater Memo\12811.01 - Stormwater Memo.docx The Project proposes one new catch basin, one new hydrodynamic separator (Stormceptor), and three new leaching basins within a stone bed. The project will also create a natural depression to further promote infiltration. The existing drainage infrastructure within Mary Dunn Road is to be maintained. Erosion and Sediment Control An erosion and sedimentation control program will be implemented to minimize temporary impacts to wetland resource areas prior to and during the construction phase of the Project. The program will incorporate BMPs specified in guidelines developed by the DEP3 and the U.S. Environmental Protection Agency (EPA)4. Non-structural practices to be used during construction include permanent seeding and pavement sweeping. These practices will be initiated as soon as practicable during construction. Structural erosion and sedimentation controls include erosion control barriers and catch basin inlet protection. Massachusetts Department of Environmental Protection (MassDEP) – Stormwater Management Standards The Project is considered a new development and has been designed to comply with all ten Stormwater Management Standards. Standard 1: No New Untreated Discharges or Erosion to Wetlands The Project has been designed to comply with Standard 1. The Project does not propose new untreated discharges to wetlands or receiving waters. All discharges will be treated through a deep-sump catch basin, a hydrodynamic separator, and leaching basins prior to discharge. Standard 2: Peak Rate Attenuation The Project has been designed to comply with Standard 2. The Project proposes to increase impervious cover by approximately 0.26 acres. This increase in impervious area is to accommodate the new parking lot, sidewalk, and a portion of the shared-use path. The majority of the impervious area is collected by the catch basin in the parking lot and discharged to the hydrodynamic separator before infiltrating via the three leaching basins. A portion of the proposed impervious area drains towards Mary Dunn Road, 3 DEP, 1997. Massachusetts Erosion and Sediment Control Guidelines for Urban and Suburban Areas: A Guide for Planners, Designers, and Muni cipal Officials. 4 EPA, 2007. Interim Developing Your Stormwater Pollution Prevention Plan: A Guide for Construction Sites. Office of Water. Report EPA 833-R-060-04. Ref: 12811.01 March 19, 2024 Page 4 \\vhb\gbl\proj\Wat-TE\12811.01\docs\memos\Stormwater Memo\12811.01 - Stormwater Memo.docx where the runoff will sheet flow along the shoulder and flow into the woods downgradient of the site. Table 1: Peak Discharge Rates (cfs) Design Point 2-year 10-year 25-year 100-year Design Point 1: Israel Pond Existing 0.0 0.0 0.1 0.6 Proposed 0.0 0.0 0.0 0.4 Design Point 2: Mary Dunn Rd Drainage Existing 0.0 0.0 0.0 0.1 Proposed 0.0 0.2 0.3 0.5 The Mary Dunn Road Drainage Design Point (Design Point 2) is a de minimis increase in peak rates. The design proposed maximizes the drainage area able to be routed to the proposed leaching basins. The additional peak flow on Mary Dunn Road will sheet flow into the woods downgradient the proposed site. Computations and supporting information regarding the hydrologic modeling are included in Attachment C. Standard 3: Stormwater Recharge The Project has been designed to comply with Standard 3. The leaching basins recharge the required recharge volume to groundwater. Supporting computations are included in Attachment C. Standard 4: Water Quality The Project has been designed to comply with Standard 4. The proposed stormwater management system implements a treatment train of BMPs that has been designed to provide 80% TSS removal of stormwater runoff from all proposed impervious surfaces as well as 44% pretreatment prior to infiltration BMPs. Supporting computations are included in Attachment C. The Long-Term Pollution Prevention Plan is included in Attachment D. Ref: 12811.01 March 19, 2024 Page 5 \\vhb\gbl\proj\Wat-TE\12811.01\docs\memos\Stormwater Memo\12811.01 - Stormwater Memo.docx Standard 5: Land Uses with Higher Potential Pollutant Loads (LUHPPLs) There are no known land uses with higher potential pollutant loads (LUHPPLs) in or with drainage areas directly tributary to the Project Area. As a result, the Project complies fully with Standard 5. Standard 6: Critical Areas The Project Area is within the Zone II wellhead protection area as indicated in Figure 4. The Project has been designed to comply with Standard 6. The Project will discharge treated storm water to a critical area and therefore has been designed with suitable BMPs sized to treat the 1-inch Water Quality Volume and provide the pretreatment requirement of 44% TSS removal prior to infiltration. Supporting computations are included in Attachment C. Proposed source controls and pollution prevention measures have been identified in the Long-Term Pollution Prevention Plan included in Attachment D. Standard 7: Redevelopments and Other Projects Subject to the Standards only to the Maximum Extent Practicable The Project is considered a new development and has been designed to comply with all ten Stormwater Management Standards. Standard 8: Construction Period Pollution Prevention and Erosion and Sedimentation Controls The overall project will disturb greater than 1 acre of land and is therefore required to obtain coverage under the Environmental Protection Agency (EPA) National Pollutant Discharge Elimination System (NPDES) Construction General Permit. As required under this permit, a Stormwater Pollution Prevention Plan (SWPPP) will be developed and submitted by the contractor before land disturbance begins. Recommended construction period pollution prevention and erosion and sedimentation controls will be finalized in the SWPPP. Ref: 12811.01 March 19, 2024 Page 6 \\vhb\gbl\proj\Wat-TE\12811.01\docs\memos\Stormwater Memo\12811.01 - Stormwater Memo.docx Standard 9: Operation and Maintenance Plan In compliance with Standard 9, a Post-Construction Stormwater Operation and Maintenance (O&M) Plan has been developed for the Project. The O&M Plan is included in Attachment D as part of the Long-Term Pollution Prevention Plan. Standard 10: Prohibition of Illicit Discharges The Project Area does not have any known illicit connections. Any illicit connections to sanitary sewer or storm drainage structures found in the project limit of work will be removed or incorporated into the project. The Long-Term Pollution Prevention Plan, provided in Attachment D, includes measures to prevent illicit discharges. Ref: 12811.01 March 19, 2024 Page 7 \\vhb\gbl\proj\Wat-TE\12811.01\docs\memos\Stormwater Memo\12811.01 - Stormwater Memo.docx Figures: Figure 1 – Aerial Overview Figure 2 – USGS Site Location Figure 3 – FEMA FIRMette Figure 4 – Critical Areas Map Figure 5 – Existing Drainage Conditions Figure 6 – Proposed Drainage Conditions Attachments: Attachment A – Stormwater Checklist Attachment B – Soils Data Attachment C – Stormwater Calculations • Existing HydroCAD • Proposed HydroCAD • Recharge Volume Calculations • Water Quality Volume Calculations • TSS Removal Calculations • Stormceptor Sizing Calculations Attachment D – Operation and Maintenance Plan and Long-Term Pollution Prevention Plan Sources: VHB, MassGIS Path: \\azrgisds\gisshare\gis3\arcgissystem\arcgisinput\NOIFigures\NOIExportMap.GPServer\extracted\p30\noi_template\NOI_Template.aprx (gmsaGIS$, 6/27/2023)N Barnstable, MA Cape Cod Rail Trail Parking Lot Figure 1: USGS Site Location 0 40002000 Feet Project Alignment BARNSTABLEMary Dunn RoadMid-cape Highway Independence Dri v e Sout h F l i n t R o c k R o a d Enoch Cobb W a y Mid-cape Highway Independen c e D r i v e Sources: VHB, MassGIS Path: \\azrgisds\gisshare\gis3\arcgissystem\arcgisinput\NOIFigures\NOIExportMap.GPServer\extracted\p30\noi_template\NOI_Template.aprx (gmsaGIS$, 6/27/2023)N Figure 2: Aerial Overview 0 500 1000250 Feet Barnstable, MA Cape Cod Rail Trail Parking Lot Project Alignment National Flood Hazard Layer FIRMette 0 500 1,000 1,500 2,000250 Feet Ü SEE FIS REPORT FOR DETAILED LEGEND AND INDEX MAP FOR FIRM PANEL LAYOUT SPECIAL FLOOD HAZARD AREAS Without Base Flood Elevation (BFE) Zone A, V, A99 With BFE or DepthZone AE, AO, AH, VE, AR Regulatory Floodway 0.2% Annual Chance Flood Hazard, Areas of 1% annual chance flood with average depth less than one foot or with drainage areas of less than one square mileZone X Future Conditions 1% Annual Chance Flood HazardZone X Area with Reduced Flood Risk due to Levee. See Notes.Zone X Area with Flood Risk due to LeveeZone D NO SCREEN Area of Minimal Flood Hazard Zone X Area of Undetermined Flood HazardZone D Channel, Culvert, or Storm Sewer Levee, Dike, or Floodwall Cross Sections with 1% Annual Chance 17.5 Water Surface Elevation Coastal Transect Coastal Transect Baseline Profile Baseline Hydrographic Feature Base Flood Elevation Line (BFE) Effective LOMRs Limit of Study Jurisdiction Boundary Digital Data Available No Digital Data Available Unmapped This map complies with FEMA's standards for the use of digital flood maps if it is not void as described below. The basemap shown complies with FEMA's basemap accuracy standards The flood hazard information is derived directly from the authoritative NFHL web services provided by FEMA. This map was exported on 6/22/2023 at 10:46 AM and does not reflect changes or amendments subsequent to this date and time. The NFHL and effective information may change or become superseded by new data over time. This map image is void if the one or more of the following map elements do not appear: basemap imagery, flood zone labels, legend, scale bar, map creation date, community identifiers, FIRM panel number, and FIRM effective date. Map images for unmapped and unmodernized areas cannot be used for regulatory purposes. Legend OTHER AREAS OF FLOOD HAZARD OTHER AREAS GENERAL STRUCTURES OTHER FEATURES MAP PANELS 8 B 20.2 The pin displayed on the map is an approximate point selected by the user and does not represent an authoritative property location. 1:6,000 70°17'8"W 41°41'10"N 70°16'31"W 41°40'43"N Basemap: USGS National Map: Orthoimagery: Data refreshed October, 2020 Flint Rock Pond Israel Pond 6 6 MaryDunnRdMaryDunnRdS Flint RockRd Independence Dr M i d -C a p e H w y M i d -C a p e H w y MassDEP, MassGIS, Esri Community Maps Contributors, Esri, HERE, Garmin, SafeGraph, GeoTechnologies, Inc, METI/NASA, USGS, EPA, NPS, US Census Bureau, USDA, Maxar Source: VHB, MassGIS Public Water Supplies Community Groundwater Well MassDEP Wellhead Protection Areas (Zone II) Approved Wellhead Protection Areas (Zone II)Path: \\vhb.com\gis\proj\Wat-TE\12811.01\gis\Project\Stormwater_Working\Stormwater Report Figure\Stormwater Report Figure.aprx (rluna, 6/27/2023)0 500 1,000 1,500 Feet N Cape Cod Rail Trail Parking Lot Barnstable, MA Figure 4: Critical Areas Map DP1 EX1 483D EX3 EX2 483C DP2 Legend SYMBOLS X X X LINETYPES SCS SOIL CLASSIFICATIONS 483C DESIGN POINT DRAINAGE AREA DESIGNATION POND DRAINAGE AREA BOUNDARY TIME OF CONCENTRATION FLOW LINE SOIL TYPE BOUNDARY 100' BUFFER ZONE WETLAND BOUNDARY PLYMOUTH-BARNSTABLE COMPLEX, ROLLING, VERY BOULDERY, HSG A \\vhb\gbl\proj\Wat-TE\12811.01\Cad\Planmisc\Stormwater\FIGURES\Existing Drainage Area.dwg 03/12/2024 Figure 5Existing Drainage Conditions Cape Cod Rail Trail Phase III Barnstable, MA037.5 75 Feet 483D PLYMOUTH-BARNSTABLE COMPLEX, HILLY, VERY BOULDERY, HSG A 259B CARVER LOAMY COARSE SAND 3 TO 8 PERCENT SLOPES, HSG A AHEADSTOPDP1 PR2 IB PR4 PR1 PR3 DP2 LB Legend SYMBOLS X X X LINETYPES SCS SOIL CLASSIFICATIONS DESIGN POINT DRAINAGE AREA DESIGNATION POND DRAINAGE AREA BOUNDARY TIME OF CONCENTRATION FLOW LINE SOIL TYPE BOUNDARY 100' BUFFER ZONE WETLAND BOUNDARY PLYMOUTH-BARNSTABLE COMPLEX, ROLLING, VERY BOULDERY, HSG A \\vhb\gbl\proj\Wat-TE\12811.01\Cad\Planmisc\Stormwater\FIGURES\Proposed Drainage Area.dwg 03/12/2024 Figure 6Proposed Drainage Conditions Cape Cod Rail Trail Phase III Barnstable, MA037.5 75 Feet PLYMOUTH-BARNSTABLE COMPLEX, HILLY, VERY BOULDERY, HSG A CARVER LOAMY COARSE SAND 3 TO 8 PERCENT SLOPES, HSG A \\vhb\gbl\proj\Wat-TE\12811.01\docs\memos\Stormwater Memo\12811.01 - Stormwater Memo.docx 101 Walnut Street Watertown, MA 02472-4026 P 617.924.1770 Attachment A Stormwater Checklist ◼ Attachment A - Stormwater Checklist • 04/01/08 Stormwater Report Checklist • Page 1 of 8 Massachusetts Department of Environmental Protection Bureau of Resource Protection - Wetlands Program Checklist for Stormwater Report A. Introduction Important: When filling out forms on the computer, use only the tab key to move your cursor - do not use the return key. A Stormwater Report must be submitted with the Notice of Intent permit application to document compliance with the Stormwater Management Standards. The following checklist is NOT a substitute for the Stormwater Report (which should provide more substantive and detailed information) but is offered here as a tool to help the applicant organize their Stormwater Management documentation for their Report and for the reviewer to assess this information in a consistent format. As noted in the Checklist, the Stormwater Report must contain the engineering computations and supporting information set forth in Volume 3 of the Massachusetts Stormwater Handbook. The Stormwater Report must be prepared and certified by a Registered Professional Engineer (RPE) licensed in the Commonwealth. The Stormwater Report must include: • The Stormwater Checklist completed and stamped by a Registered Professional Engineer (see page 2) that certifies that the Stormwater Report contains all required submittals.1 This Checklist is to be used as the cover for the completed Stormwater Report. • Applicant/Project Name • Project Address • Name of Firm and Registered Professional Engineer that prepared the Report • Long-Term Pollution Prevention Plan required by Standards 4-6 • Construction Period Pollution Prevention and Erosion and Sedimentation Control Plan required by Standard 82 • Operation and Maintenance Plan required by Standard 9 In addition to all plans and supporting information, the Stormwater Report must include a brief narrative describing stormwater management practices, including environmentally sensitive site design and LID techniques, along with a diagram depicting runoff through the proposed BMP treatment train. Plans are required to show existing and proposed conditions, identify all wetland resource areas, NRCS soil types, critical areas, Land Uses with Higher Potential Pollutant Loads (LUHPPL), and any areas on the site where infiltration rate is greater than 2.4 inches per hour. The Plans shall identify the drainage areas for both existing and proposed conditions at a scale that enables verification of supporting calculations. As noted in the Checklist, the Stormwater Management Report shall document compliance with each of the Stormwater Management Standards as provided in the Massachusetts Stormwater Handbook. The soils evaluation and calculations shall be done using the methodologies set forth in Volume 3 of the Massachusetts Stormwater Handbook. To ensure that the Stormwater Report is complete, applicants are required to fill in the Stormwater Report Checklist by checking the box to indicate that the specified information has been included in the Stormwater Report. If any of the information specified in the checklist has not been submitted, the applicant must provide an explanation. The completed Stormwater Report Checklist and Certification must be submitted with the Stormwater Report. 1 The Stormwater Report may also include the Illicit Discharge Compliance Statement required by Standard 10. If not included i n the Stormwater Report, the Illicit Discharge Compliance Statement must be submitted prior to the discharge of stormwater runoff to the post-construction best management practices. 2 For some complex projects, it may not be possible to include the Construction Period Erosion and Sedimentation Control Plan in the Stormwater Report. In that event, the issuing authority has the discretion to issue an Order of Conditions that approves the project and includes a condition requiring the proponent to submit the Construction Period Erosion and Sedimentation Control Plan before commencing any land disturbance activity on the site. Attachment A - Stormwater Checklist • 04/01/08 Stormwater Report Checklist • Page 2 of 8 B. Stormwater Checklist and Certification The following checklist is intended to serve as a guide for applicants as to the elements that ordinarily need to be addressed in a complete Stormwater Report. The checklist is also intended to provide conservation commissions and other reviewing authorities with a summary of the components necessary for a comprehensive Stormwater Report that addresses the ten Stormwater Standards. Note: Because stormwater requirements vary from project to project, it is possible that a complete Stormwater Report may not include information on some of the subjects specified in the Checklist. If it is determined that a specific item does not apply to the project under review, please note that the item is not applicable (N.A.) and provide the reasons for that determination. A complete checklist must include the Certification set forth below signed by the Registered Professional Engineer who prepared the Stormwater Report. Registered Professional Engineer’s Certification I have reviewed the Stormwater Memorandum Report, including the soil evaluation, computations, Long- term Pollution Prevention Plan, the Construction Period Erosion and Sedimentation Control Plan (if included), the Long-term Post-Construction Operation and Maintenance Plan, the Illicit Discharge Compliance Statement (if included) and the plans showing the stormwater management system, and have determined that they have been prepared in accordance with the requirements of the Stormwater Management Standards as further elaborated by the Massachusetts Stormwater Handbook. I have also determined that the information presented in the Stormwater Checklist is accurate and that the information presented in the Stormwater Memorandum Report accurately reflects conditions at the site as of the date of this permit application. Registered Professional Engineer Block and Signature Signature and Date Checklist Project Type: Is the application for new development, redevelopment, or a mix of new and redevelopment? New development Redevelopment Mix of New Development and Redevelopment Attachment A - Stormwater Checklist • 04/01/08 Stormwater Report Checklist • Page 3 of 8 Checklist (continued) LID Measures: Stormwater Standards require LID measures to be considered. Document what environmentally sensitive design and LID Techniques were considered during the planning and design of the project: No disturbance to any Wetland Resource Areas Site Design Practices (e.g. clustered development, reduced frontage setbacks) Reduced Impervious Area (Redevelopment Only) Minimizing disturbance to existing trees and shrubs LID Site Design Credit Requested: Credit 1 Credit 2 Credit 3 Use of “country drainage” versus curb and gutter conveyance and pipe Bioretention Cells (includes Rain Gardens) Constructed Stormwater Wetlands (includes Gravel Wetlands designs) Treebox Filter Water Quality Swale Grass Channel Green Roof Other (describe): Leaching Basin Standard 1: No New Untreated Discharges No new untreated discharges Outlets have been designed so there is no erosion or scour to wetlands and waters of the Commonwealth Supporting calculations specified in Volume 3 of the Massachusetts Stormwater Handbook included. Attachment A - Stormwater Checklist • 04/01/08 Stormwater Report Checklist • Page 4 of 8 Checklist (continued) Standard 2: Peak Rate Attenuation Standard 2 waiver requested because the project is located in land subject to coastal storm flowage and stormwater discharge is to a wetland subject to coastal flooding. Evaluation provided to determine whether off-site flooding increases during the 100-year 24-hour storm. Calculations provided to show that post-development peak discharge rates do not exceed pre- development rates for the 2-year and 10-year 24-hour storms. If evaluation shows that off-site flooding increases during the 100-year 24-hour storm, calculations are also provided to show that post-development peak discharge rates do not exceed pre-development rates for the 100-year 24- hour storm. Standard 3: Recharge Soil Analysis provided. Required Recharge Volume calculation provided. Required Recharge volume reduced through use of the LID site Design Credits. Sizing the infiltration, BMPs is based on the following method: Check the method used. Static Simple Dynamic Dynamic Field1 Runoff from all impervious areas at the site discharging to the infiltration BMP. Runoff from all impervious areas at the site is not discharging to the infiltration BMP and calculations are provided showing that the drainage area contributing runoff to the infiltration BMPs is sufficient to generate the required recharge volume. Recharge BMPs have been sized to infiltrate the Required Recharge Volume. Recharge BMPs have been sized to infiltrate the Required Recharge Volume only to the maximum extent practicable for the following reason: Site is comprised solely of C and D soils and/or bedrock at the land surface M.G.L. c. 21E sites pursuant to 310 CMR 40.0000 Solid Waste Landfill pursuant to 310 CMR 19.000 Project is otherwise subject to Stormwater Management Standards only to the maximum extent practicable. Calculations showing that the infiltration BMPs will drain in 72 hours are provided. Property includes a M.G.L. c. 21E site or a solid waste landfill and a mounding analysis is included. 1 80% TSS removal is required prior to discharge to infiltration BMP if Dynamic Field method is used. Attachment A - Stormwater Checklist • 04/01/08 Stormwater Report Checklist • Page 5 of 8 Checklist (continued) Standard 3: Recharge (continued) The infiltration BMP is used to attenuate peak flows during storms greater than or equal to the 10- year 24-hour storm and separation to seasonal high groundwater is less than 4 feet and a mounding analysis is provided. Documentation is provided showing that infiltration BMPs do not adversely impact nearby wetland resource areas. Standard 4: Water Quality – Maximum Extent Practicable The Long-Term Pollution Prevention Plan typically includes the following: • Good housekeeping practices; • Provisions for storing materials and waste products inside or under cover; • Vehicle washing controls; • Requirements for routine inspections and maintenance of stormwater BMPs; • Spill prevention and response plans; • Provisions for maintenance of lawns, gardens, and other landscaped areas; • Requirements for storage and use of fertilizers, herbicides, and pesticides; • Pet waste management provisions; • Provisions for operation and management of septic systems; • Provisions for solid waste management; • Snow disposal and plowing plans relative to Wetland Resource Areas; • Winter Road Salt and/or Sand Use and Storage restrictions; • Street sweeping schedules; • Provisions for prevention of illicit discharges to the stormwater management system; • Documentation that Stormwater BMPs are designed to provide for shutdown and containment in the event of a spill or discharges to or near critical areas or from LUHPPL; • Training for staff or personnel involved with implementing Long-Term Pollution Prevention Plan; • List of Emergency contacts for implementing Long-Term Pollution Prevention Plan. A Long-Term Pollution Prevention Plan is attached to Stormwater Memorandum and is included as an attachment to the Wetlands Notice of Intent. Treatment BMPs subject to the 44% TSS removal pretreatment requirement and the one inch rule for calculating the water quality volume are included, and discharge: is within the Zone II or Interim Wellhead Protection Area is near or to other critical areas is within soils with a rapid infiltration rate (greater than 2.4 inches per hour) involves runoff from land uses with higher potential pollutant loads. The Required Water Quality Volume is reduced through use of the LID site Design Credits. Calculations documenting that the treatment train meets the 80% TSS removal requirement and, if applicable, the 44% TSS removal pretreatment requirement, are provided. Attachment A - Stormwater Checklist • 04/01/08 Stormwater Report Checklist • Page 6 of 8 Checklist (continued) Standard 4: Water Quality (continued) The BMP is sized (and calculations provided) based on: The ½” or 1” Water Quality Volume or The equivalent flow rate associated with the Water Quality Volume and documentation is provided showing that the BMP treats the required water quality volume. The applicant proposes to use proprietary BMPs, and documentation supporting use of proprietary BMP and proposed TSS removal rate is provided. This documentation may be in the form of the propriety BMP checklist found in Volume 2, Chapter 4 of the Massachusetts Stormwater Handbook and submitting copies of the TARP Report, STEP Report, and/or other third party studies verifying performance of the proprietary BMPs. A TMDL exists that indicates a need to reduce pollutants other than TSS and documentation showing that the BMPs selected are consistent with the TMDL is provided. Standard 5: Land Uses With Higher Potential Pollutant Loads (LUHPPLs) – (N.A.) The NPDES Multi-Sector General Permit covers the land use and the Stormwater Pollution Prevention Plan (SWPPP) has been included with the Stormwater Report. The NPDES Multi-Sector General Permit covers the land use and the SWPPP will be submitted prior to the discharge of stormwater to the post-construction stormwater BMPs. The NPDES Multi-Sector General Permit does not cover the land use. LUHPPLs are located at the site and industry specific source control and pollution prevention measures have been proposed to reduce or eliminate the exposure of LUHPPLs to rain, snow, snow melt and runoff, and been included in the Long-Term Pollution Prevention Plan. All exposure has been eliminated. All exposure has not been eliminated and all BMPs selected are on MassDEP LUHPPL list. The LUHPPL has the potential to generate runoff with moderate to higher concentrations of oil and grease (e.g. all parking lots with >1000 vehicle trips per day) and the treatment train includes an oil grit separator, a filtering bioretention area, a sand filter or equivalent. Standard 6: Critical Areas The discharge is near or to a critical area and the treatment train includes only BMPs that MassDEP has approved for stormwater discharges to or near that particular class of critical area. Critical areas and BMPs are identified in the Stormwater Memorandum & NOI. Attachment A - Stormwater Checklist • 04/01/08 Stormwater Report Checklist • Page 7 of 8 Checklist (continued) Standard 7: Redevelopments and Other Projects Subject to the Standards only to the maximum extent practicable The project is subject to the Stormwater Management Standards only to the maximum Extent Practicable as a: Limited Project Small Residential Projects: 5-9 single family houses or 5-9 units in a multi-family development provided there is no discharge that may potentially affect a critical area. Small Residential Projects: 2-4 single family houses or 2-4 units in a multi-family development with a discharge to a critical area Marina and/or boatyard provided the hull painting, service and maintenance areas are protected from exposure to rain, snow, snow melt and runoff Bike Path and/or Foot Path Redevelopment Project Redevelopment portion of mix of new and redevelopment. Certain standards are not fully met (Standard No. 1, 8, 9, and 10 must always be fully met) and an explanation of why these standards are not met is contained in the Stormwater Report. The project involves redevelopment and a description of all measures that have been taken to improve existing conditions is provided in the Stormwater Report. The redevelopment checklist found in Volume 2 Chapter 3 of the Massachusetts Stormwater Handbook may be used to document that the proposed stormwater management system (a) complies with Standards 2, 3 and the pretreatment and structural BMP requirements of Standards 4-6 to the maximum extent practicable and (b) improves existing conditions. Standard 8: Construction Period Pollution Prevention and Erosion and Sedimentation Control A Construction Period Pollution Prevention and Erosion and Sedimentation Control Plan must include the following information: • Narrative; • Construction Period Operation and Maintenance Plan; • Names of Persons or Entity Responsible for Plan Compliance; • Construction Period Pollution Prevention Measures; • Erosion and Sedimentation Control Plan Drawings; • Detail drawings and specifications for erosion control BMPs, including sizing calculations; • Vegetation Planning; • Site Development Plan; • Construction Sequencing Plan; • Sequencing of Erosion and Sedimentation Controls; • Operation and Maintenance of Erosion and Sedimentation Controls; • Inspection Schedule; • Maintenance Schedule; • Inspection and Maintenance Log Form. A Construction Period Pollution Prevention and Erosion and Sedimentation Control Plan containing the information set forth above has been included in the Stormwater Report. Attachment A - Stormwater Checklist • 04/01/08 Stormwater Report Checklist • Page 8 of 8 Checklist (continued) Standard 8: Construction Period Pollution Prevention and Erosion and Sedimentation Control (continued) The project is highly complex and information is included in the Stormwater Report that explains why it is not possible to submit the Construction Period Pollution Prevention and Erosion and Sedimentation Control Plan with the application. A Construction Period Pollution Prevention and Erosion and Sedimentation Control has not been included in the Stormwater Report but will be submitted before land disturbance begins. The project is not covered by a NPDES Construction General Permit. The project is covered by a NPDES Construction General Permit and a copy of the SWPPP is in the Stormwater Report. The project is covered by a NPDES Construction General Permit but no SWPPP been submitted. The SWPPP will be submitted BEFORE land disturbance begins. Standard 9: Operation and Maintenance Plan The Post Construction Operation and Maintenance Plan is included in the Stormwater Report and includes the following information: Name of the stormwater management system owners; Party responsible for operation and maintenance; Schedule for implementation of routine and non-routine maintenance tasks; Plan showing the location of all stormwater BMPs maintenance access areas; Description and delineation of public safety features; Estimated operation and maintenance budget; and Operation and Maintenance Log Form. The responsible party is not the owner of the parcel where the BMP is located and the Stormwater Report includes the following submissions: A copy of the legal instrument (deed, homeowner’s association, utility trust or other legal entity) that establishes the terms of and legal responsibility for the operation and maintenance of the project site stormwater BMPs; A plan and easement deed that allows site access for the legal entity to operate and maintain BMP functions. Standard 10: Prohibition of Illicit Discharges The Long-Term Pollution Prevention Plan includes measures to prevent illicit discharges; An Illicit Discharge Compliance Statement is attached; included within the Long-Term Pollution Prevention Plan. NO Illicit Discharge Compliance Statement is attached but will be submitted prior to the discharge of any stormwater to post-construction BMPs. \\vhb\gbl\proj\Wat-TE\12811.01\docs\memos\Stormwater Memo\12811.01 - Stormwater Memo.docx 101 Walnut Street Watertown, MA 02472-4026 P 617.924.1770 Attachment B Soils Data ◼ Hydrologic Soil Group—Barnstable County, Massachusetts (Barnstable CCRT Phase III) Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 6/22/2023 Page 1 of 4461525046152804615310461534046153704615400461525046152804615310461534046153704615400393340393370393400393430393460393490393520393550393580393610 393340 393370 393400 393430 393460 393490 393520 393550 393580 41° 41' 0'' N 70° 16' 53'' W41° 41' 0'' N70° 16' 41'' W41° 40' 54'' N 70° 16' 53'' W41° 40' 54'' N 70° 16' 41'' WN Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 19N WGS84 0 50 100 200 300 Feet 0 15 30 60 90 Meters Map Scale: 1:1,270 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 1:25,000. 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: Barnstable County, Massachusetts Survey Area Data: Version 19, Sep 9, 2022 Soil map units are labeled (as space allows) for map scales 1:50,000 or larger. Date(s) aerial images were photographed: Jun 10, 2022—Jun 30, 2022 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. Hydrologic Soil Group—Barnstable County, Massachusetts (Barnstable CCRT Phase III) Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 6/22/2023 Page 2 of 4 Hydrologic Soil Group Map unit symbol Map unit name Rating Acres in AOI Percent of AOI 1 Water 1.9 31.8% 259B Carver loamy coarse sand, 3 to 8 percent slopes A 0.6 10.9% 483C Plymouth-Barnstable complex, rolling, very bouldery A 0.1 1.7% 483D Plymouth-Barnstable complex, hilly, very bouldery A 3.2 55.6% Totals for Area of Interest 5.8 100.0% Hydrologic Soil Group—Barnstable County, Massachusetts Barnstable CCRT Phase III Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 6/22/2023 Page 3 of 4 Description 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. 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. Rating Options Aggregation Method: Dominant Condition Component Percent Cutoff: None Specified Tie-break Rule: Higher Hydrologic Soil Group—Barnstable County, Massachusetts Barnstable CCRT Phase III Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 6/22/2023 Page 4 of 4 Client‐Focused, Employee‐Owned www.nobiseng.com Nobis Engineering, Inc. 585 Middlesex Street Lowell, MA 01851 T (978) 683‐0891 June 1, 2017 File No. 92140.00 Keith E. Fernandes, PE Senior Project Engineer Vanasse Hangen Brustlin, Inc. 1471 Iyannough Road Hyannis, MA 02601 (617) 607-2763 KeithFernandes@vhb.com Re: Geotechnical Letter Report Cape Cod Rail Trail Extension – Phase III Subsurface Explorations - Test Pits Barnstable & Yarmouth, Massachusetts Dear Mr. Fernandes: Nobis Engineering, Inc. (Nobis) has prepared this letter report for Vanasse Hangen Brustlin, Inc. (VHB) to present the findings of the six (6) test pits performed in support of the Cape Cod Rail Trail Extension - Phase III project. The scope of work performed by Nobis included the field location and observation of test pits at Mary Dunn Road in Barnstable, and at Higgins Crowell Road and Old Town House Road in Yarmouth (the Sites), the evaluation of the subsurface conditions encountered, and the preparation of this letter report. Our work was performed in accordance with the subconsultant authorization dated September 27, 2016. This letter report is subject to the limitations presented in Appendix A. EXISTING CONDITIONS The general location of the three Sites are depicted on the attached Figures. The test pits were all performed adjacent to roadway asphalt pavement in areas containing grass/brush ground cover with numerous trees nearby. The test pit at Mary Dunn Road was planned to be performed behind and on the east side of a gated entrance that is located west of Israel Pond. However, a Water Department representative informed us that a water main line is located on that side of the gate, and the excavation of this test pit was limited to at the west side of the gate. File No. 92140.00 Cape Cod Rail Trail Extension – Phase III, Barnstable & Yarmouth, Massachusetts Page 2 of 3 The rotary at Higgins Crowell Road contains numerous overhead wires, and buried gas and water utility lines. The site at Old Town House Road is located at the entrance to the Beverly Hills Golf Course, west of a parking lot. PROPOSED CONSTRUCTION Nobis understands that the test pits were performed in support of the design of parking areas and drainage basins to be performed by others. SUBSURFACE EXPLORATIONS Nobis observed the excavation of six (6) test pits (TP-1 through TP-6) at the Sites; collected soil samples for field classification and laboratory testing; and evaluated the subsurface conditions encountered and the results of the laboratory analyses. The test pits were completed at the areas shown on the attached Figures. Test pits were marked in the field by Nobis on January 17, 2017, using tape measurements from existing site features. The six test pits were excavated by New England Boring Contractor of Brockton, Massachusetts, on April 26, 2017, using a Kutoba KX057-4 excavator. The Nobis engineer present at the Sites classified soils encountered in the test pits in general accordance with the United States Department of Agriculture (USDA) Natural Resources Conservation Service (NRCS) grain size limits and textural soil classification methods; and the Modified Burmister classification system. More detailed descriptions and photographs of the subsurface conditions encountered in the test pits are presented on the test pit logs, provided in Appendix B. LABORATORY TESTING A total of five (5) soil samples, one from each test pit, excluding TP-6, were collected and submitted to GeoTesting Express of Acton, Massachusetts for grain size distribution and testing, including hydrometer. The soils laboratory test results are provided as Appendix C. SUBSURFACE CONDITIONS The test pits generally encountered approximately 6 to 16 inches of topsoil, overlying approximately 7.5 to 10.3 feet of Sand with various amounts of Silt and Gravel, to a termination depth of 8.1 to 10.0 feet below ground surface (bgs). Further subsurface information obtained from the test pits can be found in the test pit logs. GROUNDWATER Groundwater was not encountered in the test pits performed. Estimated seasonal high groundwater depth, as evidenced by orange staining, was not observed in test pits TP-1 through TP-6. It should be noted that fluctuations in groundwater levels can occur due to season, precipitation, temperature, and other factors different from those existing at the time the test pits were excavated. File No. 92140.00 Cape Cod Rail Trail Extension – Phase III, Barnstable & Yarmouth, Massachusetts Page 3 of 3 Thank you for the opportunity to assist you with this project. Should you require additional information, please do not hesitate to contact us. Very truly yours, Nobis Engineering, Inc. Kamil Kocia, EIT Kurt Jelinek, PE Staff Engineer Director, Transportation Services Attachments: Figures Test Pit Location Plans Appendix A Limitations Appendix B Test Pit Logs Appendix C Soils Laboratory Test Results FIGURES WILLOW STREETMARY DUNN ROADMARY DUNN ROADMARY DUNN ROADROUTE 6 - MID CAPE HIGHWAYROUTE 6 - MID CAPE HIGHWAYROUTE 6 - MID CAPE HIGHWAYROUTE 6 - MID CAPE HIGHWAYROUTE 6 - MID CAPE HIGHWAYROUTE 6 - MID CAPE HIGHWAYROUTE 6 - MID CAPE HIGHWAYROUTE 6 - MID CAPE HIGHWAYROUTE 6 - MID CAPE HIGHWAYMARY DUNN ROADINDEPENDENCE DRIVEMARY DUNN ROADCAPE COD RAIL TRAILCAPE COD RAIL TRAILWILLOW STREETRAILROADCAPE COD RAIL TRAILCAPE COD RAIL TRAILCAPE COD RAIL TRAILMARY DUNN ROADPARKING LOT NO. 1PARKING LO T N O . 2 WILLOW STREET SPURHIGGINS CROWELL ROADHIGGINS CROWELL ROAD 80080581081582015050556065707580859095100105110115120125130135140145150500505510515520525530535540545550555560565207 200 205 304300LLOW SWILLSTTREET0WI4042HIGGI N S C R O W E L L R O A DMID-CAPE HIGHWAY (ROUTE 6)MARY DUNN ROAD TOWN OF YARMOUTHBAYBERRY HILLS GOLF COURSEBAYBERRY HILLS GOLF COURSEYARMOUTHYARMOUTH WELL FIELD 2&3WELL FIELD NO. 1YARMOUTH WELL FIELD NO. 2&3ISRAEL PONDCAPE COD RAIL TRAIL (WEST)CAPE COD RAIL TRAIL (WEST)RAIL TRAILCAPE CODCAPE COD RAIL TRAIL (WEST)CAPE CTOWN OF BARNSTABLEWILLOW STREET(WEST)CCRT HIGGINS CROWELL SPURCAPE COD RAIL TRAIL FOREST STREETOLD TOWN HOUSE ROADCAPE COD RAIL TRAILCAPE COD RAIL TRAILCAPE COD RAIL TRAIL955950952954 820100010051010 10151020 10251030 1035 1040 10451047530535540545550555560565570575580585590595600605610615620 625630CA900905BAYBERRY HILLS GOLF COURSEBAYBERRY HILLS GOLF COURSECAPE COD RAIL TRAIL (EAST)WEST YARMOUTH RDCAPE COD RAIL TRAIL (EAST)FOR R E S T R O A D YARMOUTH REGIONALTRANSFER STATIONPETERHOMERPARKOLD TOWN HOUSE ROADKEY PLAN607398_HD(KEY).DWG19-Feb-2015 3:29 PMPlotted on400SCALE: 1" = 400'0 800 12001600FED. AID PROJ. NO.SHEETNO.TOTALSHEETSBARNSTABLE / YARMOUTHCAPE COD RAIL TRAIL EXTENSION182STATEMAPROJECT FILE NO.----6073983TEST PIT 1TEST PITS 2, 3, 4, and 6TEST PIT 5 TP-1 TP-1 LEGEND: TEST PIT OBSERVED BY NOBIS ENGINEERING, PERFORMED BY NEW ENGLAND BORING CONTRACTORS ON APRIL, 26, 2017. APPENDIX A – Limitations GEOTECHNICAL LIMITATIONS Explorations and Subsurface Conditions 1. The analyses and design recommendations submitted in this report are based in part upon the data obtained from subsurface explorations. The nature and extent of vari- ations between these explorations may not become evident until construction. If variations then appear evident, it will be necessary to reevaluate the recommendations of this report. In preparing this report, Nobis relied on certain information provided by the Client and other parties referenced therein which were made available to Nobis at the time of our evaluation. Nobis did not attempt to independently verify the accuracy or completeness of all information reviewed or received during the course of this evaluation. 2. The generalized soil profile described in the text is intended to convey trends in subsurface conditions. The boundaries between strata are approximate and idealized and have been developed by interpretations of widely spaced explorations and samples; actual soil transitions are probably more erratic. For specific information, refer to the exploration logs. 3. Water level readings have been made in the explorations at times and under conditions stated on the logs. These data have been reviewed and interpretations have been made in the text of this report. However, it must be noted that fluctuations in the level of the groundwater may occur due to variations in rainfall, temperature, and other factors occurring since the time measurements were made. The water table encountered in the course of the work may differ from that indicated in the Report. Recommendations for foundation drainage, waterproofing, and moisture control address the conventional geotechnical engineering aspects of seepage control. These recom- mendations may not preclude an environment that allows the infestation of mold or other biological pollutants. 4. Nobis’ geotechnical services did not include an assessment of the presence of oil or hazardous materials at the property. Consequently, we did not consider the potential impacts (if any) that contaminants in soil or groundwater may have on construction activities, or the use of structures on the property. Additional Services 5. Nobis recommends that we be retained to provide services during future site observations, design, implementation activities, construction and/or property development/ redevelopment. This will allow us the opportunity to: i) observe conditions and compliance with our recom- mendations, design concepts and/or opinions; ii) allow for changes in the event that conditions are other than anticipated; iii) provide modifications to our design recom- mendations; and iv) assess the consequences of changes in technologies and/or regulations. Use of Report 6. Nobis prepared this report on behalf of, and for the exclusive use of our Client for the stated purpose(s) and location(s) identified in our proposal and/or report. Use of this report, in whole or in part, at other locations, or for other purposes, may lead to inappropriate conclusions; and we do not accept any responsibility for the consequences of such use(s). Reliance by any party not expressly identified in the agreement, for any use, without our prior written permission, shall be at that party’s sole risk, and without any liability to Nobis. This report is for design purposes only and is not sufficient to prepare an accurate construction bid. Contractors wishing a copy of the report may secure it with the understanding that its scope is limited to design considerations only. 7. Nobis’ findings and conclusions are based on the work conducted as part of the scope of work set forth in our proposal and/or report, and reflect our professional judgment. These findings and conclusions must be con- sidered not as scientific or engineering certainties, but rather as our professional opinions considering the limited data gathered during the course of our work. If conditions other than those described in this report are found at the subject location(s), or the project design has been altered in any way, Nobis shall be so notified and afforded the opportunity to revise the report, as appropriate, to reflect the unanticipated changed conditions. 8. Nobis’ services were performed using the degree of skill and care ordinarily exercised by qualified professionals performing the same type of services, at the same time, under similar conditions, at the same or a similar property. No warranty, expressed or implied, is made. Compliance with Codes and Regulations 9. Nobis used reasonable care in identifying and interpreting applicable codes and regulations. These codes and regu- lations are subject to various, and possibly contradictory, interpretations. Compliance with codes and regulations by other parties is beyond our control. Opinion of Cost 10.This report may contain or be based on comparative cost opinions for the purpose of evaluating alternative foundation schemes. These opinions may also involve approximate quantity evaluations. It should be noted that quantity estimates may not be accurate enough for construction bids. In addition, since we are not professional estimators of labor and materials cost, the evaluation of construction costs should be considered as approximate guidelines and could vary significantly from actual costs. Nobis does not guarantee the accuracy of our cost opinions as compared to contractor’s bids for construction costs. END OF LIMITATIONS APPENDIX B – Test Pit Logs TEST PIT LOG PROJECT TEST PIT NO. SHEET 1 of 2 FILE NO. Yarmouth, MA CHKD. BY Engineer Make Kutoba Excavator Ground El. Contractor Model KX057-4 Datum Operator Capacity 1/3 cy Time Start Weather Reach 10-11 feet Time End Date Depth Strata Below Change & Subsurface Description Excavation Boulder USDA Grade Water Effort Qty/Class (ft) Level 5 9 10 11 Estimated Seasonal High Water Table approximately 5.5' bgs. 12 Groundwater not encountered 13 14 15 16 REMARKS:1) Test Pit backfilled to ground surface with excavated soils. 2) Ground elevation from survey plan prepared by others and should be considered approximate. TEST PIT PLAN NBOULDERCLASS PROPORTIONS USED EXCAVATION EFFORT 6"-8" A 0-10% Trace E = Easy 18"-36" B 10-20% Little M = Moderate >36" C 20-35% Some D = Difficult 35-50% And 9:45 AM 4/26/2017 4 - E - Sand 8 6 7 Cape Cod Rail Trail Phase 3 TP-1 92140.00 P. Clarke 44.0' NAVD-88 9:00 AM 10' 2.2' 1 K. Kocia New England Boring Contractors Dave Thompson Rain, 50s Dark Brown-Gray, Fine to Coarse SAND, some Organic Silt, several Roots. Moist. (TOPSOIL). 2 3 E S-2: Tan-Gray, Fine to Coarse SAND, trace Fine Gravel, trace Silt. Moist.E - E - S-3: Orangish Brown-Gray, Fine to Medium SAND, little Silt. Moist. Laboratory analysis performed: Grain Size (Sieve Only). Redoximorphic staining present at 5.5' bgs becoming more prominent with depth. Silt presented more by gray coloring. Sand Bottom of Exploration 10.0' bgs. Excavator having difficulty extending further due to placement. Sandy Loam Sand 10.0' Silty Sand 3.0' S-1: Tan-Orangish-Brown, Fine to Medium SAND, some Silt, trace Fine Gravel, several Roots. Moist. Topsoil 0.8' TEST PIT LOG PROJECT TEST PIT NO. SHEET 2 of 2 FILE NO. Yarmouth, MA CHKD. BY Engineer Make Kutoba Excavator Ground El. Contractor Model KX057-4 Datum Operator Capacity 1/3 cy Time Start Weather Reach 10-11 feet Time End Date REMARKS:1) Test Pit backfilled to ground surface with excavated soils. 2) Ground elevation from survey plan prepared by others and should be considered approximate. 3) Photo of completed TP-1. TEST PIT PLAN NBOULDERCLASS PROPORTIONS USED EXCAVATION EFFORT 6"-8" A 0-10% Trace E = Easy 18"-36" B 10-20% Little M = Moderate >36" C 20-35% Some D = Difficult 35-50% And TP-1 Cape Cod Rail Trail Phase 3 92140.00 P. Clarke K. Kocia 44.0' New England Boring Contractors NAVD-88 Dave Thompson 9:00 AM Rain, 50s 9:45 AM 4/26/2017 2.2' 10' TOPSOIL SILTY SAND SAND SAND APPENDIX C – Soil Laboratory Test Results Client: Nobis Engineering, Inc. Project: Cape Cod Rail Trail Location: Yarmouth, MA Project No: GTX-306387 Boring ID: TP-1 Sample ID: S-3 Depth : 5.5-10 ft Sample Type: bag Test Date: 05/12/17 Test Id: 410865 Tested By:jbr Checked By:jdt Test Comment: --- Visual Description: Moist, very pale brown silty sand Sample Comment: --- USDA Textural Classification printed 5/12/2017 1:10:46 PM Boring ID Sample ID Depth Sand, % Silt, % Clay, % Classification TP-1 S-3 5.5-10 ft 88 12 0 Sand Classifications based only on material passing the #10 sieve Sand: material passing 2.0 mm and retained on 0.05 mm diameter Silt: material passing 0.05 mm and retained on 0.002 mm diameter Clay: material passing 0.002 mm diameter Client: Nobis Engineering, Inc. Project: Cape Cod Rail Trail Location: Yarmouth, MA Project No: GTX-306387 Boring ID: TP-1 Sample ID: S-3 Depth : 5.5-10 ft Sample Type: bag Test Date: 05/12/17 Test Id: 410858 Tested By:jbr Checked By:jdt Test Comment: --- Visual Description: Moist, very pale brown silty sand Sample Comment: --- Particle Size Analysis - ASTM D422 printed 5/12/2017 1:09:27 PM 0 10 20 30 40 50 60 70 80 90 100 0.0010.010.11101001000Percent FinerGrain Size (mm)#4 #10 #20 #40 #50 #60 #100 #200 #270 % Cobble --- % Gravel 0.0 % Sand 84.1 % Silt & Clay Size 15.9 Sieve Name Sieve Size, mm Percent Finer Spec. Percent Complies #4 #10 #20 #40 #50 #60 #100 #200 #270 --- --- --- --- --- --- --- --- --- 4.75 2.00 0.85 0.42 0.30 0.25 0.15 0.075 0.053 Particle Size (mm) 0.0350 0.0229 0.0129 0.0091 0.0067 0.0047 0.0034 0.0015 100 99 95 88 81 74 36 16 12 Percent Finer 9 6 5 3 2 1 1 0 Spec. Percent Complies Coefficients D =0.3637 mm85 D =0.2067 mm60 D =0.1811 mm50 D =0.1226 mm30 D =0.0691 mm15 D =0.0400 mm10 C =5.167u C =1.818c Classification ASTM N/A AASHTO Silty Gravel and Sand (A-2-4 (0)) Sample/Test Description Sand/Gravel Particle Shape : --- Sand/Gravel Hardness : --- Dispersion Device : Apparatus A - Mech Mixer Dispersion Period : 1 minute Specific Gravity : 2.65 Separation of Sample: #270 Sieve Client: Nobis Engineering, Inc. Project: Cape Cod Rail Trail Location: Yarmouth, MA Project No: GTX-306387 Boring ID: TP-1 Sample ID: S-3 Depth : 5.5-10 ft Sample Type: bag Test Date: 05/12/17 Test Id: 410858 Tested By:jbr Checked By:jdt Test Comment: Only minus No. 10 Sieve for USDA Classification Visual Description: Moist, very pale brown silty sand Sample Comment: --- Particle Size Analysis - ASTM D422 printed 5/12/2017 1:10:21 PM 0 10 20 30 40 50 60 70 80 90 100 0.0010.010.11101001000Percent FinerGrain Size (mm)#4 #10 #20 #40 #50 #60 #100 #200 #270 % Cobble --- % Gravel 0.0 % Sand 83.9 % Silt & Clay Size 16.1 Sieve Name Sieve Size, mm Percent Finer Spec. Percent Complies #10 #20 #40 #50 #60 #100 #200 #270 --- --- --- --- --- --- --- --- --- 2.00 0.85 0.42 0.30 0.25 0.15 0.075 0.053 Particle Size (mm) 0.0350 0.0229 0.0129 0.0091 0.0067 0.0047 0.0034 0.0015 100 96 89 82 75 36 16 12 Percent Finer 9 6 5 3 2 1 1 0 Spec. Percent Complies Coefficients D =0.3476 mm85 D =0.2048 mm60 D =0.1797 mm50 D =0.1212 mm30 D =0.0681 mm15 D =0.0397 mm10 C =5.159u C =1.807c Classification ASTM N/A AASHTO Silty Gravel and Sand (A-2-4 (0)) Sample/Test Description Sand/Gravel Particle Shape : --- Sand/Gravel Hardness : --- Dispersion Device : Apparatus A - Mech Mixer Dispersion Period : 1 minute Specific Gravity : 2.65 Separation of Sample: #270 Sieve \\vhb\gbl\proj\Wat-TE\12811.01\docs\memos\Stormwater Memo\12811.01 - Stormwater Memo.docx 101 Walnut Street Watertown, MA 02472-4026 P 617.924.1770 Attachment C Stormwater Calculations ◼ Existing HydroCAD Calculations Proposed HydroCAD Calculations Recharge Volume Calculations Water Quality Volume Calculations TSS Removal Calculations Stormceptor Sizing Calculations Mary Dunn - EX1 Subcat Mary Dunn - EX1 Mary Dunn - EX2 Subcat Mary Dunn - EX2 Mary Dunn - EX3 Subcat Mary Dunn - EX3 DP1 Israel Pond DP2 Mary Dunn Road Drainage Routing Diagram for EX Prepared by VHB, Inc, Printed 3/8/2024 HydroCAD® 10.20-3c s/n 01038 © 2023 HydroCAD Software Solutions LLC Subcat Reach Pond Link NRCC 24-hr C 2-Year Rainfall=3.38"EX Printed 3/8/2024Prepared by VHB, Inc Page 7HydroCAD® 10.20-3c s/n 01038 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment Mary Dunn - EX1: Subcat Mary Dunn - EX1 [45] Hint: Runoff=Zero Runoff = 0.00 cfs @ 5.00 hrs, Volume= 0.000 af, Depth= 0.00" Routed to Link DP1 : Israel Pond Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-30.00 hrs, dt= 0.05 hrs NRCC 24-hr C 2-Year Rainfall=3.38" Area (ac) CN Description 0.149 76 Gravel roads, HSG A 1.158 30 Woods, Good, HSG A 1.306 35 Weighted Average 1.306 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, min Subcatchment Mary Dunn - EX1: Subcat Mary Dunn - EX1 Runoff Hydrograph Time (hours) 30292827262524232221201918171615141312111098765Flow (cfs)1 0 NRCC 24-hr C 2-Year Rainfall=3.38" Runoff Area=1.306 ac Runoff Volume=0.000 af Runoff Depth=0.00" Tc=6.0 min CN=35 0.00 cfs NRCC 24-hr C 2-Year Rainfall=3.38"EX Printed 3/8/2024Prepared by VHB, Inc Page 8HydroCAD® 10.20-3c s/n 01038 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment Mary Dunn - EX2: Subcat Mary Dunn - EX2 [45] Hint: Runoff=Zero Runoff = 0.00 cfs @ 5.00 hrs, Volume= 0.000 af, Depth= 0.00" Routed to Link DP2 : Mary Dunn Road Drainage Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-30.00 hrs, dt= 0.05 hrs NRCC 24-hr C 2-Year Rainfall=3.38" Area (ac) CN Description 0.017 39 >75% Grass cover, Good, HSG A 0.004 76 Gravel roads, HSG A 0.003 98 Paved roads w/curbs & sewers, HSG A 0.067 30 Woods, Good, HSG A 0.091 36 Weighted Average 0.088 96.70% Pervious Area 0.003 3.30% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Min. Subcatchment Mary Dunn - EX2: Subcat Mary Dunn - EX2 Runoff Hydrograph Time (hours) 30292827262524232221201918171615141312111098765Flow (cfs)1 0 NRCC 24-hr C 2-Year Rainfall=3.38" Runoff Area=0.091 ac Runoff Volume=0.000 af Runoff Depth=0.00" Tc=6.0 min CN=36 0.00 cfs NRCC 24-hr C 2-Year Rainfall=3.38"EX Printed 3/8/2024Prepared by VHB, Inc Page 9HydroCAD® 10.20-3c s/n 01038 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment Mary Dunn - EX3: Subcat Mary Dunn - EX3 [45] Hint: Runoff=Zero Runoff = 0.00 cfs @ 5.00 hrs, Volume= 0.000 af, Depth= 0.00" Routed to Link DP2 : Mary Dunn Road Drainage Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-30.00 hrs, dt= 0.05 hrs NRCC 24-hr C 2-Year Rainfall=3.38" Area (ac) CN Description 0.417 30 Woods, Good, HSG A 0.417 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Min. Subcatchment Mary Dunn - EX3: Subcat Mary Dunn - EX3 Runoff Hydrograph Time (hours) 30292827262524232221201918171615141312111098765Flow (cfs)1 0 NRCC 24-hr C 2-Year Rainfall=3.38" Runoff Area=0.417 ac Runoff Volume=0.000 af Runoff Depth=0.00" Tc=6.0 min CN=30 0.00 cfs NRCC 24-hr C 2-Year Rainfall=3.38"EX Printed 3/8/2024Prepared by VHB, Inc Page 10HydroCAD® 10.20-3c s/n 01038 © 2023 HydroCAD Software Solutions LLC Summary for Link DP1: Israel Pond Inflow Area = 1.306 ac, 0.00% Impervious, Inflow Depth = 0.00" for 2-Year event Inflow = 0.00 cfs @ 5.00 hrs, Volume= 0.000 af Primary = 0.00 cfs @ 5.00 hrs, Volume= 0.000 af, Atten= 0%, Lag= 0.0 min Routed to nonexistent node 3L Primary outflow = Inflow, Time Span= 5.00-30.00 hrs, dt= 0.05 hrs Link DP1: Israel Pond Inflow Primary Hydrograph Time (hours) 30292827262524232221201918171615141312111098765Flow (cfs)1 0 Inflow Area=1.306 ac 0.00 cfs 0.00 cfs NRCC 24-hr C 2-Year Rainfall=3.38"EX Printed 3/8/2024Prepared by VHB, Inc Page 11HydroCAD® 10.20-3c s/n 01038 © 2023 HydroCAD Software Solutions LLC Summary for Link DP2: Mary Dunn Road Drainage Inflow Area = 0.508 ac, 0.59% Impervious, Inflow Depth = 0.00" for 2-Year event Inflow = 0.00 cfs @ 5.00 hrs, Volume= 0.000 af Primary = 0.00 cfs @ 5.00 hrs, Volume= 0.000 af, Atten= 0%, Lag= 0.0 min Routed to nonexistent node 3L Primary outflow = Inflow, Time Span= 5.00-30.00 hrs, dt= 0.05 hrs Link DP2: Mary Dunn Road Drainage Inflow Primary Hydrograph Time (hours) 30292827262524232221201918171615141312111098765Flow (cfs)1 0 Inflow Area=0.508 ac 0.00 cfs 0.00 cfs NRCC 24-hr C 10-Year Rainfall=4.93"EX Printed 3/8/2024Prepared by VHB, Inc Page 12HydroCAD® 10.20-3c s/n 01038 © 2023 HydroCAD Software Solutions LLC Time span=5.00-30.00 hrs, dt=0.05 hrs, 501 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Runoff Area=1.306 ac 0.00% Impervious Runoff Depth=0.07"Subcatchment Mary Dunn - EX1: Subcat Tc=6.0 min CN=35 Runoff=0.01 cfs 0.008 af Runoff Area=0.091 ac 3.30% Impervious Runoff Depth=0.10"Subcatchment Mary Dunn - EX2: Subcat Tc=6.0 min CN=36 Runoff=0.00 cfs 0.001 af Runoff Area=0.417 ac 0.00% Impervious Runoff Depth=0.00"Subcatchment Mary Dunn - EX3: Subcat Tc=6.0 min CN=30 Runoff=0.00 cfs 0.000 af Inflow=0.01 cfs 0.008 afLink DP1: Israel Pond Primary=0.01 cfs 0.008 af Inflow=0.00 cfs 0.001 afLink DP2: Mary Dunn Road Drainage Primary=0.00 cfs 0.001 af Total Runoff Area = 1.814 ac Runoff Volume = 0.009 af Average Runoff Depth = 0.06" 99.83% Pervious = 1.811 ac 0.17% Impervious = 0.003 ac NRCC 24-hr C 10-Year Rainfall=4.93"EX Printed 3/8/2024Prepared by VHB, Inc Page 13HydroCAD® 10.20-3c s/n 01038 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment Mary Dunn - EX1: Subcat Mary Dunn - EX1 Runoff = 0.01 cfs @ 16.54 hrs, Volume= 0.008 af, Depth= 0.07" Routed to Link DP1 : Israel Pond Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-30.00 hrs, dt= 0.05 hrs NRCC 24-hr C 10-Year Rainfall=4.93" Area (ac) CN Description 0.149 76 Gravel roads, HSG A 1.158 30 Woods, Good, HSG A 1.306 35 Weighted Average 1.306 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, min Subcatchment Mary Dunn - EX1: Subcat Mary Dunn - EX1 Runoff Hydrograph Time (hours) 30292827262524232221201918171615141312111098765Flow (cfs)0.011 0.011 0.01 0.01 0.009 0.009 0.008 0.008 0.007 0.007 0.006 0.006 0.005 0.005 0.004 0.004 0.003 0.003 0.002 0.002 0.001 0.001 0.000 0 NRCC 24-hr C 10-Year Rainfall=4.93" Runoff Area=1.306 ac Runoff Volume=0.008 af Runoff Depth=0.07" Tc=6.0 min CN=35 0.01 cfs NRCC 24-hr C 10-Year Rainfall=4.93"EX Printed 3/8/2024Prepared by VHB, Inc Page 14HydroCAD® 10.20-3c s/n 01038 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment Mary Dunn - EX2: Subcat Mary Dunn - EX2 Runoff = 0.00 cfs @ 14.55 hrs, Volume= 0.001 af, Depth= 0.10" Routed to Link DP2 : Mary Dunn Road Drainage Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-30.00 hrs, dt= 0.05 hrs NRCC 24-hr C 10-Year Rainfall=4.93" Area (ac) CN Description 0.017 39 >75% Grass cover, Good, HSG A 0.004 76 Gravel roads, HSG A 0.003 98 Paved roads w/curbs & sewers, HSG A 0.067 30 Woods, Good, HSG A 0.091 36 Weighted Average 0.088 96.70% Pervious Area 0.003 3.30% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Min. Subcatchment Mary Dunn - EX2: Subcat Mary Dunn - EX2 Runoff Hydrograph Time (hours) 30292827262524232221201918171615141312111098765Flow (cfs)0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0 0 0 NRCC 24-hr C 10-Year Rainfall=4.93" Runoff Area=0.091 ac Runoff Volume=0.001 af Runoff Depth=0.10" Tc=6.0 min CN=36 0.00 cfs NRCC 24-hr C 10-Year Rainfall=4.93"EX Printed 3/8/2024Prepared by VHB, Inc Page 15HydroCAD® 10.20-3c s/n 01038 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment Mary Dunn - EX3: Subcat Mary Dunn - EX3 Runoff = 0.00 cfs @ 24.00 hrs, Volume= 0.000 af, Depth= 0.00" Routed to Link DP2 : Mary Dunn Road Drainage Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-30.00 hrs, dt= 0.05 hrs NRCC 24-hr C 10-Year Rainfall=4.93" Area (ac) CN Description 0.417 30 Woods, Good, HSG A 0.417 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Min. Subcatchment Mary Dunn - EX3: Subcat Mary Dunn - EX3 Runoff Hydrograph Time (hours) 30292827262524232221201918171615141312111098765Flow (cfs)0.001 0.001 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0 0 0 NRCC 24-hr C 10-Year Rainfall=4.93" Runoff Area=0.417 ac Runoff Volume=0.000 af Runoff Depth=0.00" Tc=6.0 min CN=30 0.00 cfs NRCC 24-hr C 10-Year Rainfall=4.93"EX Printed 3/8/2024Prepared by VHB, Inc Page 16HydroCAD® 10.20-3c s/n 01038 © 2023 HydroCAD Software Solutions LLC Summary for Link DP1: Israel Pond Inflow Area = 1.306 ac, 0.00% Impervious, Inflow Depth = 0.07" for 10-Year event Inflow = 0.01 cfs @ 16.54 hrs, Volume= 0.008 af Primary = 0.01 cfs @ 16.54 hrs, Volume= 0.008 af, Atten= 0%, Lag= 0.0 min Routed to nonexistent node 3L Primary outflow = Inflow, Time Span= 5.00-30.00 hrs, dt= 0.05 hrs Link DP1: Israel Pond Inflow Primary Hydrograph Time (hours) 30292827262524232221201918171615141312111098765Flow (cfs)0.011 0.011 0.01 0.01 0.009 0.009 0.008 0.008 0.007 0.007 0.006 0.006 0.005 0.005 0.004 0.004 0.003 0.003 0.002 0.002 0.001 0.001 0.000 0 Inflow Area=1.306 ac 0.01 cfs 0.01 cfs NRCC 24-hr C 10-Year Rainfall=4.93"EX Printed 3/8/2024Prepared by VHB, Inc Page 17HydroCAD® 10.20-3c s/n 01038 © 2023 HydroCAD Software Solutions LLC Summary for Link DP2: Mary Dunn Road Drainage Inflow Area = 0.508 ac, 0.59% Impervious, Inflow Depth = 0.02" for 10-Year event Inflow = 0.00 cfs @ 24.00 hrs, Volume= 0.001 af Primary = 0.00 cfs @ 24.00 hrs, Volume= 0.001 af, Atten= 0%, Lag= 0.0 min Routed to nonexistent node 3L Primary outflow = Inflow, Time Span= 5.00-30.00 hrs, dt= 0.05 hrs Link DP2: Mary Dunn Road Drainage Inflow Primary Hydrograph Time (hours) 30292827262524232221201918171615141312111098765Flow (cfs)0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.000 0.000 0.000 0.000 0 0 Inflow Area=0.508 ac 0.00 cfs 0.00 cfs NRCC 24-hr C 25-Year Rainfall=5.89"EX Printed 3/8/2024Prepared by VHB, Inc Page 18HydroCAD® 10.20-3c s/n 01038 © 2023 HydroCAD Software Solutions LLC Time span=5.00-30.00 hrs, dt=0.05 hrs, 501 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Runoff Area=1.306 ac 0.00% Impervious Runoff Depth=0.23"Subcatchment Mary Dunn - EX1: Subcat Tc=6.0 min CN=35 Runoff=0.05 cfs 0.025 af Runoff Area=0.091 ac 3.30% Impervious Runoff Depth=0.27"Subcatchment Mary Dunn - EX2: Subcat Tc=6.0 min CN=36 Runoff=0.00 cfs 0.002 af Runoff Area=0.417 ac 0.00% Impervious Runoff Depth=0.06"Subcatchment Mary Dunn - EX3: Subcat Tc=6.0 min CN=30 Runoff=0.00 cfs 0.002 af Inflow=0.05 cfs 0.025 afLink DP1: Israel Pond Primary=0.05 cfs 0.025 af Inflow=0.00 cfs 0.004 afLink DP2: Mary Dunn Road Drainage Primary=0.00 cfs 0.004 af Total Runoff Area = 1.814 ac Runoff Volume = 0.029 af Average Runoff Depth = 0.19" 99.83% Pervious = 1.811 ac 0.17% Impervious = 0.003 ac NRCC 24-hr C 25-Year Rainfall=5.89"EX Printed 3/8/2024Prepared by VHB, Inc Page 19HydroCAD® 10.20-3c s/n 01038 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment Mary Dunn - EX1: Subcat Mary Dunn - EX1 Runoff = 0.05 cfs @ 12.95 hrs, Volume= 0.025 af, Depth= 0.23" Routed to Link DP1 : Israel Pond Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-30.00 hrs, dt= 0.05 hrs NRCC 24-hr C 25-Year Rainfall=5.89" Area (ac) CN Description 0.149 76 Gravel roads, HSG A 1.158 30 Woods, Good, HSG A 1.306 35 Weighted Average 1.306 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, min Subcatchment Mary Dunn - EX1: Subcat Mary Dunn - EX1 Runoff Hydrograph Time (hours) 30292827262524232221201918171615141312111098765Flow (cfs)0.05 0.048 0.046 0.044 0.042 0.04 0.038 0.036 0.034 0.032 0.03 0.028 0.026 0.024 0.022 0.02 0.018 0.016 0.014 0.012 0.01 0.008 0.006 0.004 0.002 0 NRCC 24-hr C 25-Year Rainfall=5.89" Runoff Area=1.306 ac Runoff Volume=0.025 af Runoff Depth=0.23" Tc=6.0 min CN=35 0.05 cfs NRCC 24-hr C 25-Year Rainfall=5.89"EX Printed 3/8/2024Prepared by VHB, Inc Page 20HydroCAD® 10.20-3c s/n 01038 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment Mary Dunn - EX2: Subcat Mary Dunn - EX2 Runoff = 0.00 cfs @ 12.55 hrs, Volume= 0.002 af, Depth= 0.27" Routed to Link DP2 : Mary Dunn Road Drainage Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-30.00 hrs, dt= 0.05 hrs NRCC 24-hr C 25-Year Rainfall=5.89" Area (ac) CN Description 0.017 39 >75% Grass cover, Good, HSG A 0.004 76 Gravel roads, HSG A 0.003 98 Paved roads w/curbs & sewers, HSG A 0.067 30 Woods, Good, HSG A 0.091 36 Weighted Average 0.088 96.70% Pervious Area 0.003 3.30% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Min. Subcatchment Mary Dunn - EX2: Subcat Mary Dunn - EX2 Runoff Hydrograph Time (hours) 30292827262524232221201918171615141312111098765Flow (cfs)0.005 0.005 0.004 0.004 0.004 0.004 0.004 0.003 0.003 0.003 0.003 0.003 0.002 0.002 0.002 0.002 0.002 0.001 0.001 0.001 0.001 0.001 0.000 0.000 0 NRCC 24-hr C 25-Year Rainfall=5.89" Runoff Area=0.091 ac Runoff Volume=0.002 af Runoff Depth=0.27" Tc=6.0 min CN=36 0.00 cfs NRCC 24-hr C 25-Year Rainfall=5.89"EX Printed 3/8/2024Prepared by VHB, Inc Page 21HydroCAD® 10.20-3c s/n 01038 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment Mary Dunn - EX3: Subcat Mary Dunn - EX3 Runoff = 0.00 cfs @ 21.14 hrs, Volume= 0.002 af, Depth= 0.06" Routed to Link DP2 : Mary Dunn Road Drainage Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-30.00 hrs, dt= 0.05 hrs NRCC 24-hr C 25-Year Rainfall=5.89" Area (ac) CN Description 0.417 30 Woods, Good, HSG A 0.417 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Min. Subcatchment Mary Dunn - EX3: Subcat Mary Dunn - EX3 Runoff Hydrograph Time (hours) 30292827262524232221201918171615141312111098765Flow (cfs)0.003 0.003 0.003 0.002 0.002 0.002 0.002 0.002 0.001 0.001 0.001 0.001 0.001 0.000 0.000 0 NRCC 24-hr C 25-Year Rainfall=5.89" Runoff Area=0.417 ac Runoff Volume=0.002 af Runoff Depth=0.06" Tc=6.0 min CN=30 0.00 cfs NRCC 24-hr C 25-Year Rainfall=5.89"EX Printed 3/8/2024Prepared by VHB, Inc Page 22HydroCAD® 10.20-3c s/n 01038 © 2023 HydroCAD Software Solutions LLC Summary for Link DP1: Israel Pond Inflow Area = 1.306 ac, 0.00% Impervious, Inflow Depth = 0.23" for 25-Year event Inflow = 0.05 cfs @ 12.95 hrs, Volume= 0.025 af Primary = 0.05 cfs @ 12.95 hrs, Volume= 0.025 af, Atten= 0%, Lag= 0.0 min Routed to nonexistent node 3L Primary outflow = Inflow, Time Span= 5.00-30.00 hrs, dt= 0.05 hrs Link DP1: Israel Pond Inflow Primary Hydrograph Time (hours) 30292827262524232221201918171615141312111098765Flow (cfs)0.05 0.045 0.04 0.035 0.03 0.025 0.02 0.015 0.01 0.005 0 Inflow Area=1.306 ac 0.05 cfs 0.05 cfs NRCC 24-hr C 25-Year Rainfall=5.89"EX Printed 3/8/2024Prepared by VHB, Inc Page 23HydroCAD® 10.20-3c s/n 01038 © 2023 HydroCAD Software Solutions LLC Summary for Link DP2: Mary Dunn Road Drainage Inflow Area = 0.508 ac, 0.59% Impervious, Inflow Depth = 0.10" for 25-Year event Inflow = 0.00 cfs @ 16.54 hrs, Volume= 0.004 af Primary = 0.00 cfs @ 16.54 hrs, Volume= 0.004 af, Atten= 0%, Lag= 0.0 min Routed to nonexistent node 3L Primary outflow = Inflow, Time Span= 5.00-30.00 hrs, dt= 0.05 hrs Link DP2: Mary Dunn Road Drainage Inflow Primary Hydrograph Time (hours) 30292827262524232221201918171615141312111098765Flow (cfs)0.005 0.005 0.004 0.004 0.003 0.003 0.002 0.002 0.001 0.001 0 Inflow Area=0.508 ac 0.00 cfs 0.00 cfs NRCC 24-hr C 100-Year Rainfall=7.83"EX Printed 3/8/2024Prepared by VHB, Inc Page 24HydroCAD® 10.20-3c s/n 01038 © 2023 HydroCAD Software Solutions LLC Time span=5.00-30.00 hrs, dt=0.05 hrs, 501 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Runoff Area=1.306 ac 0.00% Impervious Runoff Depth=0.75"Subcatchment Mary Dunn - EX1: Subcat Tc=6.0 min CN=35 Runoff=0.55 cfs 0.081 af Runoff Area=0.091 ac 3.30% Impervious Runoff Depth=0.83"Subcatchment Mary Dunn - EX2: Subcat Tc=6.0 min CN=36 Runoff=0.05 cfs 0.006 af Runoff Area=0.417 ac 0.00% Impervious Runoff Depth=0.38"Subcatchment Mary Dunn - EX3: Subcat Tc=6.0 min CN=30 Runoff=0.03 cfs 0.013 af Inflow=0.55 cfs 0.081 afLink DP1: Israel Pond Primary=0.55 cfs 0.081 af Inflow=0.05 cfs 0.019 afLink DP2: Mary Dunn Road Drainage Primary=0.05 cfs 0.019 af Total Runoff Area = 1.814 ac Runoff Volume = 0.101 af Average Runoff Depth = 0.67" 99.83% Pervious = 1.811 ac 0.17% Impervious = 0.003 ac NRCC 24-hr C 100-Year Rainfall=7.83"EX Printed 3/8/2024Prepared by VHB, Inc Page 25HydroCAD® 10.20-3c s/n 01038 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment Mary Dunn - EX1: Subcat Mary Dunn - EX1 Runoff = 0.55 cfs @ 12.17 hrs, Volume= 0.081 af, Depth= 0.75" Routed to Link DP1 : Israel Pond Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-30.00 hrs, dt= 0.05 hrs NRCC 24-hr C 100-Year Rainfall=7.83" Area (ac) CN Description 0.149 76 Gravel roads, HSG A 1.158 30 Woods, Good, HSG A 1.306 35 Weighted Average 1.306 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, min Subcatchment Mary Dunn - EX1: Subcat Mary Dunn - EX1 Runoff Hydrograph Time (hours) 30292827262524232221201918171615141312111098765Flow (cfs)0.6 0.55 0.5 0.45 0.4 0.35 0.3 0.25 0.2 0.15 0.1 0.05 0 NRCC 24-hr C 100-Year Rainfall=7.83" Runoff Area=1.306 ac Runoff Volume=0.081 af Runoff Depth=0.75" Tc=6.0 min CN=35 0.55 cfs NRCC 24-hr C 100-Year Rainfall=7.83"EX Printed 3/8/2024Prepared by VHB, Inc Page 26HydroCAD® 10.20-3c s/n 01038 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment Mary Dunn - EX2: Subcat Mary Dunn - EX2 Runoff = 0.05 cfs @ 12.16 hrs, Volume= 0.006 af, Depth= 0.83" Routed to Link DP2 : Mary Dunn Road Drainage Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-30.00 hrs, dt= 0.05 hrs NRCC 24-hr C 100-Year Rainfall=7.83" Area (ac) CN Description 0.017 39 >75% Grass cover, Good, HSG A 0.004 76 Gravel roads, HSG A 0.003 98 Paved roads w/curbs & sewers, HSG A 0.067 30 Woods, Good, HSG A 0.091 36 Weighted Average 0.088 96.70% Pervious Area 0.003 3.30% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Min. Subcatchment Mary Dunn - EX2: Subcat Mary Dunn - EX2 Runoff Hydrograph Time (hours) 30292827262524232221201918171615141312111098765Flow (cfs)0.055 0.05 0.045 0.04 0.035 0.03 0.025 0.02 0.015 0.01 0.005 0 NRCC 24-hr C 100-Year Rainfall=7.83" Runoff Area=0.091 ac Runoff Volume=0.006 af Runoff Depth=0.83" Tc=6.0 min CN=36 0.05 cfs NRCC 24-hr C 100-Year Rainfall=7.83"EX Printed 3/8/2024Prepared by VHB, Inc Page 27HydroCAD® 10.20-3c s/n 01038 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment Mary Dunn - EX3: Subcat Mary Dunn - EX3 Runoff = 0.03 cfs @ 12.55 hrs, Volume= 0.013 af, Depth= 0.38" Routed to Link DP2 : Mary Dunn Road Drainage Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-30.00 hrs, dt= 0.05 hrs NRCC 24-hr C 100-Year Rainfall=7.83" Area (ac) CN Description 0.417 30 Woods, Good, HSG A 0.417 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Min. Subcatchment Mary Dunn - EX3: Subcat Mary Dunn - EX3 Runoff Hydrograph Time (hours) 30292827262524232221201918171615141312111098765Flow (cfs)0.032 0.03 0.028 0.026 0.024 0.022 0.02 0.018 0.016 0.014 0.012 0.01 0.008 0.006 0.004 0.002 0 NRCC 24-hr C 100-Year Rainfall=7.83" Runoff Area=0.417 ac Runoff Volume=0.013 af Runoff Depth=0.38" Tc=6.0 min CN=30 0.03 cfs NRCC 24-hr C 100-Year Rainfall=7.83"EX Printed 3/8/2024Prepared by VHB, Inc Page 28HydroCAD® 10.20-3c s/n 01038 © 2023 HydroCAD Software Solutions LLC Summary for Link DP1: Israel Pond Inflow Area = 1.306 ac, 0.00% Impervious, Inflow Depth = 0.75" for 100-Year event Inflow = 0.55 cfs @ 12.17 hrs, Volume= 0.081 af Primary = 0.55 cfs @ 12.17 hrs, Volume= 0.081 af, Atten= 0%, Lag= 0.0 min Routed to nonexistent node 3L Primary outflow = Inflow, Time Span= 5.00-30.00 hrs, dt= 0.05 hrs Link DP1: Israel Pond Inflow Primary Hydrograph Time (hours) 30292827262524232221201918171615141312111098765Flow (cfs)0.6 0.55 0.5 0.45 0.4 0.35 0.3 0.25 0.2 0.15 0.1 0.05 0 Inflow Area=1.306 ac 0.55 cfs 0.55 cfs NRCC 24-hr C 100-Year Rainfall=7.83"EX Printed 3/8/2024Prepared by VHB, Inc Page 29HydroCAD® 10.20-3c s/n 01038 © 2023 HydroCAD Software Solutions LLC Summary for Link DP2: Mary Dunn Road Drainage Inflow Area = 0.508 ac, 0.59% Impervious, Inflow Depth = 0.46" for 100-Year event Inflow = 0.05 cfs @ 12.53 hrs, Volume= 0.019 af Primary = 0.05 cfs @ 12.53 hrs, Volume= 0.019 af, Atten= 0%, Lag= 0.0 min Routed to nonexistent node 3L Primary outflow = Inflow, Time Span= 5.00-30.00 hrs, dt= 0.05 hrs Link DP2: Mary Dunn Road Drainage Inflow Primary Hydrograph Time (hours) 30292827262524232221201918171615141312111098765Flow (cfs)0.055 0.05 0.045 0.04 0.035 0.03 0.025 0.02 0.015 0.01 0.005 0 Inflow Area=0.508 ac 0.05 cfs 0.05 cfs Mary Dunn - PR1 Subcat Mary Dunn - PR1 Mary Dunn - PR2 Subcat Mary Dunn - PR2 Mary Dunn - PR3 Subcat Mary Dunn - PR3 Mary Dunn - PR4 Subcat Mary Dunn - PR4 1P Infiltration Basin (Nature Depressed Area) LB Leaching Basins (3) DP1 Israel Pond DP2 Mary Dunn Road Drainage Routing Diagram for PR Prepared by VHB, Inc, Printed 3/19/2024 HydroCAD® 10.20-3c s/n 01038 © 2023 HydroCAD Software Solutions LLC Subcat Reach Pond Link NRCC 24-hr C 2-Year Rainfall=3.38"PR Printed 3/19/2024Prepared by VHB, Inc Page 2HydroCAD® 10.20-3c s/n 01038 © 2023 HydroCAD Software Solutions LLC Time span=0.00-48.00 hrs, dt=0.03 hrs, 1601 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Runoff Area=0.237 ac 81.43% Impervious Runoff Depth=2.07"Subcatchment Mary Dunn - PR1: Subcat Tc=6.0 min CN=87 Runoff=0.61 cfs 0.041 af Runoff Area=1.024 ac 1.46% Impervious Runoff Depth=0.00"Subcatchment Mary Dunn - PR2: Subcat Tc=6.0 min CN=37 Runoff=0.00 cfs 0.000 af Runoff Area=0.149 ac 36.91% Impervious Runoff Depth=0.37"Subcatchment Mary Dunn - PR3: Subcat Tc=6.0 min CN=57 Runoff=0.04 cfs 0.005 af Runoff Area=0.472 ac 0.00% Impervious Runoff Depth=0.00"Subcatchment Mary Dunn - PR4: Subcat Tc=6.0 min CN=35 Runoff=0.00 cfs 0.000 af Peak Elev=42.00' Storage=0 cf Inflow=0.00 cfs 0.000 afPond 1P: Infiltration Basin (Nature Depressed Discarded=0.00 cfs 0.000 af Primary=0.00 cfs 0.000 af Outflow=0.00 cfs 0.000 af Peak Elev=33.03' Storage=506 cf Inflow=0.61 cfs 0.041 afPond LB: Leaching Basins (3) Discarded=0.08 cfs 0.041 af Primary=0.00 cfs 0.000 af Outflow=0.08 cfs 0.041 af Inflow=0.00 cfs 0.000 afLink DP1: Israel Pond Primary=0.00 cfs 0.000 af Inflow=0.04 cfs 0.005 afLink DP2: Mary Dunn Road Drainage Primary=0.04 cfs 0.005 af Total Runoff Area = 1.882 ac Runoff Volume = 0.046 af Average Runoff Depth = 0.29" 86.02% Pervious = 1.619 ac 13.98% Impervious = 0.263 ac NRCC 24-hr C 2-Year Rainfall=3.38"PR Printed 3/19/2024Prepared by VHB, Inc Page 3HydroCAD® 10.20-3c s/n 01038 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment Mary Dunn - PR1: Subcat Mary Dunn - PR1 Runoff = 0.61 cfs @ 12.13 hrs, Volume= 0.041 af, Depth= 2.07" Routed to Pond LB : Leaching Basins (3) Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs NRCC 24-hr C 2-Year Rainfall=3.38" Area (ac) CN Description 0.036 39 >75% Grass cover, Good, HSG A 0.193 98 Paved roads w/curbs & sewers, HSG A 0.008 30 Woods, Good, HSG A 0.237 87 Weighted Average 0.044 18.57% Pervious Area 0.193 81.43% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, min Subcatchment Mary Dunn - PR1: Subcat Mary Dunn - PR1 Runoff Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)0.65 0.6 0.55 0.5 0.45 0.4 0.35 0.3 0.25 0.2 0.15 0.1 0.05 0 NRCC 24-hr C 2-Year Rainfall=3.38" Runoff Area=0.237 ac Runoff Volume=0.041 af Runoff Depth=2.07" Tc=6.0 min CN=87 0.61 cfs NRCC 24-hr C 2-Year Rainfall=3.38"PR Printed 3/19/2024Prepared by VHB, Inc Page 4HydroCAD® 10.20-3c s/n 01038 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment Mary Dunn - PR2: Subcat Mary Dunn - PR2 [45] Hint: Runoff=Zero Runoff = 0.00 cfs @ 0.00 hrs, Volume= 0.000 af, Depth= 0.00" Routed to Pond 1P : Infiltration Basin (Nature Depressed Area) Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs NRCC 24-hr C 2-Year Rainfall=3.38" Area (ac) CN Description 0.085 39 >75% Grass cover, Good, HSG A 0.128 76 Gravel roads, HSG A 0.796 30 Woods, Good, HSG A 0.015 98 Paved roads w/curbs & sewers, HSG A 1.024 37 Weighted Average 1.009 98.54% Pervious Area 0.015 1.46% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Min Subcatchment Mary Dunn - PR2: Subcat Mary Dunn - PR2 Runoff Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)1 0 NRCC 24-hr C 2-Year Rainfall=3.38" Runoff Area=1.024 ac Runoff Volume=0.000 af Runoff Depth=0.00" Tc=6.0 min CN=37 0.00 cfs NRCC 24-hr C 2-Year Rainfall=3.38"PR Printed 3/19/2024Prepared by VHB, Inc Page 5HydroCAD® 10.20-3c s/n 01038 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment Mary Dunn - PR3: Subcat Mary Dunn - PR3 Runoff = 0.04 cfs @ 12.16 hrs, Volume= 0.005 af, Depth= 0.37" Routed to Link DP2 : Mary Dunn Road Drainage Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs NRCC 24-hr C 2-Year Rainfall=3.38" Area (ac) CN Description 0.027 39 >75% Grass cover, Good, HSG A 0.055 98 Paved roads w/curbs & sewers, HSG A 0.067 30 Woods, Good, HSG A 0.149 57 Weighted Average 0.094 63.09% Pervious Area 0.055 36.91% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Min Subcatchment Mary Dunn - PR3: Subcat Mary Dunn - PR3 Runoff Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)0.042 0.04 0.038 0.036 0.034 0.032 0.03 0.028 0.026 0.024 0.022 0.02 0.018 0.016 0.014 0.012 0.01 0.008 0.006 0.004 0.002 0 NRCC 24-hr C 2-Year Rainfall=3.38" Runoff Area=0.149 ac Runoff Volume=0.005 af Runoff Depth=0.37" Tc=6.0 min CN=57 0.04 cfs NRCC 24-hr C 2-Year Rainfall=3.38"PR Printed 3/19/2024Prepared by VHB, Inc Page 6HydroCAD® 10.20-3c s/n 01038 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment Mary Dunn - PR4: Subcat Mary Dunn - PR4 [45] Hint: Runoff=Zero Runoff = 0.00 cfs @ 0.00 hrs, Volume= 0.000 af, Depth= 0.00" Routed to Pond 1P : Infiltration Basin (Nature Depressed Area) Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs NRCC 24-hr C 2-Year Rainfall=3.38" Area (ac) CN Description 0.253 39 >75% Grass cover, Good, HSG A 0.218 30 Woods, Good, HSG A 0.472 35 Weighted Average 0.472 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, min Subcatchment Mary Dunn - PR4: Subcat Mary Dunn - PR4 Runoff Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)1 0 NRCC 24-hr C 2-Year Rainfall=3.38" Runoff Area=0.472 ac Runoff Volume=0.000 af Runoff Depth=0.00" Tc=6.0 min CN=35 0.00 cfs NRCC 24-hr C 2-Year Rainfall=3.38"PR Printed 3/19/2024Prepared by VHB, Inc Page 7HydroCAD® 10.20-3c s/n 01038 © 2023 HydroCAD Software Solutions LLC Summary for Pond 1P: Infiltration Basin (Nature Depressed Area) Inflow Area = 1.496 ac, 1.00% Impervious, Inflow Depth = 0.00" for 2-Year event Inflow = 0.00 cfs @ 0.00 hrs, Volume= 0.000 af Outflow = 0.00 cfs @ 0.00 hrs, Volume= 0.000 af, Atten= 0%, Lag= 0.0 min Discarded = 0.00 cfs @ 0.00 hrs, Volume= 0.000 af Primary = 0.00 cfs @ 0.00 hrs, Volume= 0.000 af Routed to Link DP1 : Israel Pond Routing by Stor-Ind method, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs Peak Elev= 42.00' @ 0.00 hrs Surf.Area= 50 sf Storage= 0 cf Plug-Flow detention time= (not calculated: initial storage exceeds outflow) Center-of-Mass det. time= (not calculated: no inflow) Volume Invert Avail.Storage Storage Description #1 42.00' 2,113 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 42.00 50 0 0 43.00 264 157 157 44.00 521 393 550 45.00 521 521 1,071 46.00 521 521 1,592 47.00 521 521 2,113 Device Routing Invert Outlet Devices #1 Discarded 42.00'8.270 in/hr Exfiltration over Surface area #2 Primary 46.90'10.0' long x 10.0' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 Coef. (English) 2.49 2.56 2.70 2.69 2.68 2.69 2.67 2.64 Discarded OutFlow Max=0.00 cfs @ 0.00 hrs HW=42.00' (Free Discharge) 1=Exfiltration (Passes 0.00 cfs of 0.01 cfs potential flow) Primary OutFlow Max=0.00 cfs @ 0.00 hrs HW=42.00' (Free Discharge) 2=Broad-Crested Rectangular Weir ( Controls 0.00 cfs) NRCC 24-hr C 2-Year Rainfall=3.38"PR Printed 3/19/2024Prepared by VHB, Inc Page 8HydroCAD® 10.20-3c s/n 01038 © 2023 HydroCAD Software Solutions LLC Pond 1P: Infiltration Basin (Nature Depressed Area) Inflow Outflow Discarded Primary Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)1 0 Inflow Area=1.496 ac Peak Elev=42.00' Storage=0 cf 0.00 cfs 0.00 cfs 0.00 cfs 0.00 cfs NRCC 24-hr C 2-Year Rainfall=3.38"PR Printed 3/19/2024Prepared by VHB, Inc Page 9HydroCAD® 10.20-3c s/n 01038 © 2023 HydroCAD Software Solutions LLC Summary for Pond LB: Leaching Basins (3) Inflow Area = 0.237 ac, 81.43% Impervious, Inflow Depth = 2.07" for 2-Year event Inflow = 0.61 cfs @ 12.13 hrs, Volume= 0.041 af Outflow = 0.08 cfs @ 11.76 hrs, Volume= 0.041 af, Atten= 86%, Lag= 0.0 min Discarded = 0.08 cfs @ 11.76 hrs, Volume= 0.041 af Primary = 0.00 cfs @ 0.00 hrs, Volume= 0.000 af Routed to Link DP1 : Israel Pond Routing by Stor-Ind method, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs / 2 Peak Elev= 33.03' @ 12.71 hrs Surf.Area= 432 sf Storage= 506 cf Plug-Flow detention time= 41.9 min calculated for 0.041 af (100% of inflow) Center-of-Mass det. time= 41.9 min ( 867.0 - 825.1 ) Volume Invert Avail.Storage Storage Description #1 34.10' 551 cf 6.00'D x 6.50'H Leaching Basin x 3 Inside #2 #2 30.10' 1,698 cf 12.00'W x 36.00'L x 11.10'H Prismatoid 4,795 cf Overall - 551 cf Embedded = 4,244 cf x 40.0% Voids #3 40.60' 8 cf 2.00'D x 2.70'H Vertical Cone/Cylinder 2,257 cf Total Available Storage Device Routing Invert Outlet Devices #1 Device 3 42.10'10.0' long x 10.0' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 Coef. (English) 2.49 2.56 2.70 2.69 2.68 2.69 2.67 2.64 #2 Discarded 30.10'8.270 in/hr Exfiltration over Surface area #3 Primary 42.10'2.5" x 2.5" Horiz. Orifice/Grate X 6.00 columns X 6 rows C= 0.600 in 24.0" x 24.0" Grate (39% open area) Limited to weir flow at low heads #4 Primary 39.30'12.0" Round Outlet L= 5.0' RCP, rounded edge headwall, Ke= 0.100 Inlet / Outlet Invert= 39.30' / 39.00' S= 0.0600 '/' Cc= 0.900 n= 0.012, Flow Area= 0.79 sf Discarded OutFlow Max=0.08 cfs @ 11.76 hrs HW=30.23' (Free Discharge) 2=Exfiltration (Exfiltration Controls 0.08 cfs) Primary OutFlow Max=0.00 cfs @ 0.00 hrs HW=30.10' (Free Discharge) 3=Orifice/Grate ( Controls 0.00 cfs) 1=Broad-Crested Rectangular Weir ( Controls 0.00 cfs) 4=Outlet ( Controls 0.00 cfs) NRCC 24-hr C 2-Year Rainfall=3.38"PR Printed 3/19/2024Prepared by VHB, Inc Page 10HydroCAD® 10.20-3c s/n 01038 © 2023 HydroCAD Software Solutions LLC Pond LB: Leaching Basins (3) Inflow Outflow Discarded Primary Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)0.65 0.6 0.55 0.5 0.45 0.4 0.35 0.3 0.25 0.2 0.15 0.1 0.05 0 Inflow Area=0.237 ac Peak Elev=33.03' Storage=506 cf 0.61 cfs 0.08 cfs 0.08 cfs 0.00 cfs NRCC 24-hr C 2-Year Rainfall=3.38"PR Printed 3/19/2024Prepared by VHB, Inc Page 11HydroCAD® 10.20-3c s/n 01038 © 2023 HydroCAD Software Solutions LLC Summary for Link DP1: Israel Pond Inflow Area = 1.733 ac, 12.00% Impervious, Inflow Depth = 0.00" for 2-Year event Inflow = 0.00 cfs @ 0.00 hrs, Volume= 0.000 af Primary = 0.00 cfs @ 0.00 hrs, Volume= 0.000 af, Atten= 0%, Lag= 0.0 min Routed to nonexistent node 6L Primary outflow = Inflow, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs Link DP1: Israel Pond Inflow Primary Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)1 0 Inflow Area=1.733 ac 0.00 cfs 0.00 cfs NRCC 24-hr C 2-Year Rainfall=3.38"PR Printed 3/19/2024Prepared by VHB, Inc Page 12HydroCAD® 10.20-3c s/n 01038 © 2023 HydroCAD Software Solutions LLC Summary for Link DP2: Mary Dunn Road Drainage Inflow Area = 0.149 ac, 36.91% Impervious, Inflow Depth = 0.37" for 2-Year event Inflow = 0.04 cfs @ 12.16 hrs, Volume= 0.005 af Primary = 0.04 cfs @ 12.16 hrs, Volume= 0.005 af, Atten= 0%, Lag= 0.0 min Routed to nonexistent node 6L Primary outflow = Inflow, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs Link DP2: Mary Dunn Road Drainage Inflow Primary Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)0.042 0.04 0.038 0.036 0.034 0.032 0.03 0.028 0.026 0.024 0.022 0.02 0.018 0.016 0.014 0.012 0.01 0.008 0.006 0.004 0.002 0 Inflow Area=0.149 ac 0.04 cfs 0.04 cfs NRCC 24-hr C 10-Year Rainfall=4.93"PR Printed 3/19/2024Prepared by VHB, Inc Page 13HydroCAD® 10.20-3c s/n 01038 © 2023 HydroCAD Software Solutions LLC Time span=0.00-48.00 hrs, dt=0.03 hrs, 1601 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Runoff Area=0.237 ac 81.43% Impervious Runoff Depth=3.50"Subcatchment Mary Dunn - PR1: Subcat Tc=6.0 min CN=87 Runoff=1.01 cfs 0.069 af Runoff Area=1.024 ac 1.46% Impervious Runoff Depth=0.13"Subcatchment Mary Dunn - PR2: Subcat Tc=6.0 min CN=37 Runoff=0.01 cfs 0.011 af Runoff Area=0.149 ac 36.91% Impervious Runoff Depth=1.07"Subcatchment Mary Dunn - PR3: Subcat Tc=6.0 min CN=57 Runoff=0.18 cfs 0.013 af Runoff Area=0.472 ac 0.00% Impervious Runoff Depth=0.07"Subcatchment Mary Dunn - PR4: Subcat Tc=6.0 min CN=35 Runoff=0.00 cfs 0.003 af Peak Elev=42.18' Storage=13 cf Inflow=0.02 cfs 0.014 afPond 1P: Infiltration Basin (Nature Depressed Discarded=0.02 cfs 0.014 af Primary=0.00 cfs 0.000 af Outflow=0.02 cfs 0.014 af Peak Elev=35.95' Storage=1,105 cf Inflow=1.01 cfs 0.069 afPond LB: Leaching Basins (3) Discarded=0.08 cfs 0.069 af Primary=0.00 cfs 0.000 af Outflow=0.08 cfs 0.069 af Inflow=0.00 cfs 0.000 afLink DP1: Israel Pond Primary=0.00 cfs 0.000 af Inflow=0.18 cfs 0.013 afLink DP2: Mary Dunn Road Drainage Primary=0.18 cfs 0.013 af Total Runoff Area = 1.882 ac Runoff Volume = 0.096 af Average Runoff Depth = 0.61" 86.02% Pervious = 1.619 ac 13.98% Impervious = 0.263 ac NRCC 24-hr C 10-Year Rainfall=4.93"PR Printed 3/19/2024Prepared by VHB, Inc Page 14HydroCAD® 10.20-3c s/n 01038 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment Mary Dunn - PR1: Subcat Mary Dunn - PR1 Runoff = 1.01 cfs @ 12.13 hrs, Volume= 0.069 af, Depth= 3.50" Routed to Pond LB : Leaching Basins (3) Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs NRCC 24-hr C 10-Year Rainfall=4.93" Area (ac) CN Description 0.036 39 >75% Grass cover, Good, HSG A 0.193 98 Paved roads w/curbs & sewers, HSG A 0.008 30 Woods, Good, HSG A 0.237 87 Weighted Average 0.044 18.57% Pervious Area 0.193 81.43% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, min Subcatchment Mary Dunn - PR1: Subcat Mary Dunn - PR1 Runoff Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)1 0 NRCC 24-hr C 10-Year Rainfall=4.93" Runoff Area=0.237 ac Runoff Volume=0.069 af Runoff Depth=3.50" Tc=6.0 min CN=87 1.01 cfs NRCC 24-hr C 10-Year Rainfall=4.93"PR Printed 3/19/2024Prepared by VHB, Inc Page 15HydroCAD® 10.20-3c s/n 01038 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment Mary Dunn - PR2: Subcat Mary Dunn - PR2 Runoff = 0.01 cfs @ 14.25 hrs, Volume= 0.011 af, Depth= 0.13" Routed to Pond 1P : Infiltration Basin (Nature Depressed Area) Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs NRCC 24-hr C 10-Year Rainfall=4.93" Area (ac) CN Description 0.085 39 >75% Grass cover, Good, HSG A 0.128 76 Gravel roads, HSG A 0.796 30 Woods, Good, HSG A 0.015 98 Paved roads w/curbs & sewers, HSG A 1.024 37 Weighted Average 1.009 98.54% Pervious Area 0.015 1.46% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Min Subcatchment Mary Dunn - PR2: Subcat Mary Dunn - PR2 Runoff Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)0.016 0.015 0.014 0.013 0.012 0.011 0.01 0.009 0.008 0.007 0.006 0.005 0.004 0.003 0.002 0.001 0 NRCC 24-hr C 10-Year Rainfall=4.93" Runoff Area=1.024 ac Runoff Volume=0.011 af Runoff Depth=0.13" Tc=6.0 min CN=37 0.01 cfs NRCC 24-hr C 10-Year Rainfall=4.93"PR Printed 3/19/2024Prepared by VHB, Inc Page 16HydroCAD® 10.20-3c s/n 01038 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment Mary Dunn - PR3: Subcat Mary Dunn - PR3 Runoff = 0.18 cfs @ 12.14 hrs, Volume= 0.013 af, Depth= 1.07" Routed to Link DP2 : Mary Dunn Road Drainage Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs NRCC 24-hr C 10-Year Rainfall=4.93" Area (ac) CN Description 0.027 39 >75% Grass cover, Good, HSG A 0.055 98 Paved roads w/curbs & sewers, HSG A 0.067 30 Woods, Good, HSG A 0.149 57 Weighted Average 0.094 63.09% Pervious Area 0.055 36.91% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Min Subcatchment Mary Dunn - PR3: Subcat Mary Dunn - PR3 Runoff Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)0.19 0.18 0.17 0.16 0.15 0.14 0.13 0.12 0.11 0.1 0.09 0.08 0.07 0.06 0.05 0.04 0.03 0.02 0.01 0 NRCC 24-hr C 10-Year Rainfall=4.93" Runoff Area=0.149 ac Runoff Volume=0.013 af Runoff Depth=1.07" Tc=6.0 min CN=57 0.18 cfs NRCC 24-hr C 10-Year Rainfall=4.93"PR Printed 3/19/2024Prepared by VHB, Inc Page 17HydroCAD® 10.20-3c s/n 01038 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment Mary Dunn - PR4: Subcat Mary Dunn - PR4 Runoff = 0.00 cfs @ 16.54 hrs, Volume= 0.003 af, Depth= 0.07" Routed to Pond 1P : Infiltration Basin (Nature Depressed Area) Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs NRCC 24-hr C 10-Year Rainfall=4.93" Area (ac) CN Description 0.253 39 >75% Grass cover, Good, HSG A 0.218 30 Woods, Good, HSG A 0.472 35 Weighted Average 0.472 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, min Subcatchment Mary Dunn - PR4: Subcat Mary Dunn - PR4 Runoff Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)0.004 0.004 0.004 0.003 0.003 0.003 0.003 0.003 0.002 0.002 0.002 0.002 0.002 0.001 0.001 0.001 0.001 0.001 0.000 0.000 0 NRCC 24-hr C 10-Year Rainfall=4.93" Runoff Area=0.472 ac Runoff Volume=0.003 af Runoff Depth=0.07" Tc=6.0 min CN=35 0.00 cfs NRCC 24-hr C 10-Year Rainfall=4.93"PR Printed 3/19/2024Prepared by VHB, Inc Page 18HydroCAD® 10.20-3c s/n 01038 © 2023 HydroCAD Software Solutions LLC Summary for Pond 1P: Infiltration Basin (Nature Depressed Area) Inflow Area = 1.496 ac, 1.00% Impervious, Inflow Depth = 0.11" for 10-Year event Inflow = 0.02 cfs @ 14.44 hrs, Volume= 0.014 af Outflow = 0.02 cfs @ 14.91 hrs, Volume= 0.014 af, Atten= 5%, Lag= 28.1 min Discarded = 0.02 cfs @ 14.91 hrs, Volume= 0.014 af Primary = 0.00 cfs @ 0.00 hrs, Volume= 0.000 af Routed to Link DP1 : Israel Pond Routing by Stor-Ind method, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs Peak Elev= 42.18' @ 14.91 hrs Surf.Area= 89 sf Storage= 13 cf Plug-Flow detention time= 9.0 min calculated for 0.014 af (100% of inflow) Center-of-Mass det. time= 9.0 min ( 1,098.7 - 1,089.7 ) Volume Invert Avail.Storage Storage Description #1 42.00' 2,113 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 42.00 50 0 0 43.00 264 157 157 44.00 521 393 550 45.00 521 521 1,071 46.00 521 521 1,592 47.00 521 521 2,113 Device Routing Invert Outlet Devices #1 Discarded 42.00'8.270 in/hr Exfiltration over Surface area #2 Primary 46.90'10.0' long x 10.0' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 Coef. (English) 2.49 2.56 2.70 2.69 2.68 2.69 2.67 2.64 Discarded OutFlow Max=0.02 cfs @ 14.91 hrs HW=42.18' (Free Discharge) 1=Exfiltration (Exfiltration Controls 0.02 cfs) Primary OutFlow Max=0.00 cfs @ 0.00 hrs HW=42.00' (Free Discharge) 2=Broad-Crested Rectangular Weir ( Controls 0.00 cfs) NRCC 24-hr C 10-Year Rainfall=4.93"PR Printed 3/19/2024Prepared by VHB, Inc Page 19HydroCAD® 10.20-3c s/n 01038 © 2023 HydroCAD Software Solutions LLC Pond 1P: Infiltration Basin (Nature Depressed Area) Inflow Outflow Discarded Primary Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)0.02 0.019 0.018 0.017 0.016 0.015 0.014 0.013 0.012 0.011 0.01 0.009 0.008 0.007 0.006 0.005 0.004 0.003 0.002 0.001 0 Inflow Area=1.496 ac Peak Elev=42.18' Storage=13 cf 0.02 cfs 0.02 cfs 0.02 cfs 0.00 cfs NRCC 24-hr C 10-Year Rainfall=4.93"PR Printed 3/19/2024Prepared by VHB, Inc Page 20HydroCAD® 10.20-3c s/n 01038 © 2023 HydroCAD Software Solutions LLC Summary for Pond LB: Leaching Basins (3) Inflow Area = 0.237 ac, 81.43% Impervious, Inflow Depth = 3.50" for 10-Year event Inflow = 1.01 cfs @ 12.13 hrs, Volume= 0.069 af Outflow = 0.08 cfs @ 11.40 hrs, Volume= 0.069 af, Atten= 92%, Lag= 0.0 min Discarded = 0.08 cfs @ 11.40 hrs, Volume= 0.069 af Primary = 0.00 cfs @ 0.00 hrs, Volume= 0.000 af Routed to Link DP1 : Israel Pond Routing by Stor-Ind method, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs / 2 Peak Elev= 35.95' @ 13.21 hrs Surf.Area= 432 sf Storage= 1,105 cf Plug-Flow detention time= 102.6 min calculated for 0.069 af (100% of inflow) Center-of-Mass det. time= 102.6 min ( 911.2 - 808.6 ) Volume Invert Avail.Storage Storage Description #1 34.10' 551 cf 6.00'D x 6.50'H Leaching Basin x 3 Inside #2 #2 30.10' 1,698 cf 12.00'W x 36.00'L x 11.10'H Prismatoid 4,795 cf Overall - 551 cf Embedded = 4,244 cf x 40.0% Voids #3 40.60' 8 cf 2.00'D x 2.70'H Vertical Cone/Cylinder 2,257 cf Total Available Storage Device Routing Invert Outlet Devices #1 Device 3 42.10'10.0' long x 10.0' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 Coef. (English) 2.49 2.56 2.70 2.69 2.68 2.69 2.67 2.64 #2 Discarded 30.10'8.270 in/hr Exfiltration over Surface area #3 Primary 42.10'2.5" x 2.5" Horiz. Orifice/Grate X 6.00 columns X 6 rows C= 0.600 in 24.0" x 24.0" Grate (39% open area) Limited to weir flow at low heads #4 Primary 39.30'12.0" Round Outlet L= 5.0' RCP, rounded edge headwall, Ke= 0.100 Inlet / Outlet Invert= 39.30' / 39.00' S= 0.0600 '/' Cc= 0.900 n= 0.012, Flow Area= 0.79 sf Discarded OutFlow Max=0.08 cfs @ 11.40 hrs HW=30.24' (Free Discharge) 2=Exfiltration (Exfiltration Controls 0.08 cfs) Primary OutFlow Max=0.00 cfs @ 0.00 hrs HW=30.10' (Free Discharge) 3=Orifice/Grate ( Controls 0.00 cfs) 1=Broad-Crested Rectangular Weir ( Controls 0.00 cfs) 4=Outlet ( Controls 0.00 cfs) NRCC 24-hr C 10-Year Rainfall=4.93"PR Printed 3/19/2024Prepared by VHB, Inc Page 21HydroCAD® 10.20-3c s/n 01038 © 2023 HydroCAD Software Solutions LLC Pond LB: Leaching Basins (3) Inflow Outflow Discarded Primary Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)1 0 Inflow Area=0.237 ac Peak Elev=35.95' Storage=1,105 cf 1.01 cfs 0.08 cfs 0.08 cfs 0.00 cfs NRCC 24-hr C 10-Year Rainfall=4.93"PR Printed 3/19/2024Prepared by VHB, Inc Page 22HydroCAD® 10.20-3c s/n 01038 © 2023 HydroCAD Software Solutions LLC Summary for Link DP1: Israel Pond Inflow Area = 1.733 ac, 12.00% Impervious, Inflow Depth = 0.00" for 10-Year event Inflow = 0.00 cfs @ 0.00 hrs, Volume= 0.000 af Primary = 0.00 cfs @ 0.00 hrs, Volume= 0.000 af, Atten= 0%, Lag= 0.0 min Routed to nonexistent node 6L Primary outflow = Inflow, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs Link DP1: Israel Pond Inflow Primary Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)1 0 Inflow Area=1.733 ac 0.00 cfs 0.00 cfs NRCC 24-hr C 10-Year Rainfall=4.93"PR Printed 3/19/2024Prepared by VHB, Inc Page 23HydroCAD® 10.20-3c s/n 01038 © 2023 HydroCAD Software Solutions LLC Summary for Link DP2: Mary Dunn Road Drainage Inflow Area = 0.149 ac, 36.91% Impervious, Inflow Depth = 1.07" for 10-Year event Inflow = 0.18 cfs @ 12.14 hrs, Volume= 0.013 af Primary = 0.18 cfs @ 12.14 hrs, Volume= 0.013 af, Atten= 0%, Lag= 0.0 min Routed to nonexistent node 6L Primary outflow = Inflow, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs Link DP2: Mary Dunn Road Drainage Inflow Primary Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)0.19 0.18 0.17 0.16 0.15 0.14 0.13 0.12 0.11 0.1 0.09 0.08 0.07 0.06 0.05 0.04 0.03 0.02 0.01 0 Inflow Area=0.149 ac 0.18 cfs 0.18 cfs NRCC 24-hr C 25-Year Rainfall=5.89"PR Printed 3/19/2024Prepared by VHB, Inc Page 24HydroCAD® 10.20-3c s/n 01038 © 2023 HydroCAD Software Solutions LLC Time span=0.00-48.00 hrs, dt=0.03 hrs, 1601 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Runoff Area=0.237 ac 81.43% Impervious Runoff Depth=4.41"Subcatchment Mary Dunn - PR1: Subcat Tc=6.0 min CN=87 Runoff=1.25 cfs 0.087 af Runoff Area=1.024 ac 1.46% Impervious Runoff Depth=0.32"Subcatchment Mary Dunn - PR2: Subcat Tc=6.0 min CN=37 Runoff=0.07 cfs 0.027 af Runoff Area=0.149 ac 36.91% Impervious Runoff Depth=1.61"Subcatchment Mary Dunn - PR3: Subcat Tc=6.0 min CN=57 Runoff=0.29 cfs 0.020 af Runoff Area=0.472 ac 0.00% Impervious Runoff Depth=0.23"Subcatchment Mary Dunn - PR4: Subcat Tc=6.0 min CN=35 Runoff=0.02 cfs 0.009 af Peak Elev=43.01' Storage=161 cf Inflow=0.08 cfs 0.036 afPond 1P: Infiltration Basin (Nature Depressed Discarded=0.05 cfs 0.036 af Primary=0.00 cfs 0.000 af Outflow=0.05 cfs 0.036 af Peak Elev=37.87' Storage=1,536 cf Inflow=1.25 cfs 0.087 afPond LB: Leaching Basins (3) Discarded=0.08 cfs 0.087 af Primary=0.00 cfs 0.000 af Outflow=0.08 cfs 0.087 af Inflow=0.00 cfs 0.000 afLink DP1: Israel Pond Primary=0.00 cfs 0.000 af Inflow=0.29 cfs 0.020 afLink DP2: Mary Dunn Road Drainage Primary=0.29 cfs 0.020 af Total Runoff Area = 1.882 ac Runoff Volume = 0.143 af Average Runoff Depth = 0.91" 86.02% Pervious = 1.619 ac 13.98% Impervious = 0.263 ac NRCC 24-hr C 25-Year Rainfall=5.89"PR Printed 3/19/2024Prepared by VHB, Inc Page 25HydroCAD® 10.20-3c s/n 01038 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment Mary Dunn - PR1: Subcat Mary Dunn - PR1 Runoff = 1.25 cfs @ 12.13 hrs, Volume= 0.087 af, Depth= 4.41" Routed to Pond LB : Leaching Basins (3) Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs NRCC 24-hr C 25-Year Rainfall=5.89" Area (ac) CN Description 0.036 39 >75% Grass cover, Good, HSG A 0.193 98 Paved roads w/curbs & sewers, HSG A 0.008 30 Woods, Good, HSG A 0.237 87 Weighted Average 0.044 18.57% Pervious Area 0.193 81.43% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, min Subcatchment Mary Dunn - PR1: Subcat Mary Dunn - PR1 Runoff Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)1 0 NRCC 24-hr C 25-Year Rainfall=5.89" Runoff Area=0.237 ac Runoff Volume=0.087 af Runoff Depth=4.41" Tc=6.0 min CN=87 1.25 cfs NRCC 24-hr C 25-Year Rainfall=5.89"PR Printed 3/19/2024Prepared by VHB, Inc Page 26HydroCAD® 10.20-3c s/n 01038 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment Mary Dunn - PR2: Subcat Mary Dunn - PR2 Runoff = 0.07 cfs @ 12.54 hrs, Volume= 0.027 af, Depth= 0.32" Routed to Pond 1P : Infiltration Basin (Nature Depressed Area) Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs NRCC 24-hr C 25-Year Rainfall=5.89" Area (ac) CN Description 0.085 39 >75% Grass cover, Good, HSG A 0.128 76 Gravel roads, HSG A 0.796 30 Woods, Good, HSG A 0.015 98 Paved roads w/curbs & sewers, HSG A 1.024 37 Weighted Average 1.009 98.54% Pervious Area 0.015 1.46% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Min Subcatchment Mary Dunn - PR2: Subcat Mary Dunn - PR2 Runoff Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)0.075 0.07 0.065 0.06 0.055 0.05 0.045 0.04 0.035 0.03 0.025 0.02 0.015 0.01 0.005 0 NRCC 24-hr C 25-Year Rainfall=5.89" Runoff Area=1.024 ac Runoff Volume=0.027 af Runoff Depth=0.32" Tc=6.0 min CN=37 0.07 cfs NRCC 24-hr C 25-Year Rainfall=5.89"PR Printed 3/19/2024Prepared by VHB, Inc Page 27HydroCAD® 10.20-3c s/n 01038 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment Mary Dunn - PR3: Subcat Mary Dunn - PR3 Runoff = 0.29 cfs @ 12.14 hrs, Volume= 0.020 af, Depth= 1.61" Routed to Link DP2 : Mary Dunn Road Drainage Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs NRCC 24-hr C 25-Year Rainfall=5.89" Area (ac) CN Description 0.027 39 >75% Grass cover, Good, HSG A 0.055 98 Paved roads w/curbs & sewers, HSG A 0.067 30 Woods, Good, HSG A 0.149 57 Weighted Average 0.094 63.09% Pervious Area 0.055 36.91% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Min Subcatchment Mary Dunn - PR3: Subcat Mary Dunn - PR3 Runoff Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)0.3 0.28 0.26 0.24 0.22 0.2 0.18 0.16 0.14 0.12 0.1 0.08 0.06 0.04 0.02 0 NRCC 24-hr C 25-Year Rainfall=5.89" Runoff Area=0.149 ac Runoff Volume=0.020 af Runoff Depth=1.61" Tc=6.0 min CN=57 0.29 cfs NRCC 24-hr C 25-Year Rainfall=5.89"PR Printed 3/19/2024Prepared by VHB, Inc Page 28HydroCAD® 10.20-3c s/n 01038 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment Mary Dunn - PR4: Subcat Mary Dunn - PR4 Runoff = 0.02 cfs @ 12.95 hrs, Volume= 0.009 af, Depth= 0.23" Routed to Pond 1P : Infiltration Basin (Nature Depressed Area) Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs NRCC 24-hr C 25-Year Rainfall=5.89" Area (ac) CN Description 0.253 39 >75% Grass cover, Good, HSG A 0.218 30 Woods, Good, HSG A 0.472 35 Weighted Average 0.472 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, min Subcatchment Mary Dunn - PR4: Subcat Mary Dunn - PR4 Runoff Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)0.018 0.017 0.016 0.015 0.014 0.013 0.012 0.011 0.01 0.009 0.008 0.007 0.006 0.005 0.004 0.003 0.002 0.001 0 NRCC 24-hr C 25-Year Rainfall=5.89" Runoff Area=0.472 ac Runoff Volume=0.009 af Runoff Depth=0.23" Tc=6.0 min CN=35 0.02 cfs NRCC 24-hr C 25-Year Rainfall=5.89"PR Printed 3/19/2024Prepared by VHB, Inc Page 29HydroCAD® 10.20-3c s/n 01038 © 2023 HydroCAD Software Solutions LLC Summary for Pond 1P: Infiltration Basin (Nature Depressed Area) Inflow Area = 1.496 ac, 1.00% Impervious, Inflow Depth = 0.29" for 25-Year event Inflow = 0.08 cfs @ 12.54 hrs, Volume= 0.036 af Outflow = 0.05 cfs @ 14.26 hrs, Volume= 0.036 af, Atten= 38%, Lag= 103.3 min Discarded = 0.05 cfs @ 14.26 hrs, Volume= 0.036 af Primary = 0.00 cfs @ 0.00 hrs, Volume= 0.000 af Routed to Link DP1 : Israel Pond Routing by Stor-Ind method, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs Peak Elev= 43.01' @ 14.26 hrs Surf.Area= 267 sf Storage= 161 cf Plug-Flow detention time= 37.6 min calculated for 0.036 af (100% of inflow) Center-of-Mass det. time= 37.6 min ( 1,053.9 - 1,016.3 ) Volume Invert Avail.Storage Storage Description #1 42.00' 2,113 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 42.00 50 0 0 43.00 264 157 157 44.00 521 393 550 45.00 521 521 1,071 46.00 521 521 1,592 47.00 521 521 2,113 Device Routing Invert Outlet Devices #1 Discarded 42.00'8.270 in/hr Exfiltration over Surface area #2 Primary 46.90'10.0' long x 10.0' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 Coef. (English) 2.49 2.56 2.70 2.69 2.68 2.69 2.67 2.64 Discarded OutFlow Max=0.05 cfs @ 14.26 hrs HW=43.01' (Free Discharge) 1=Exfiltration (Exfiltration Controls 0.05 cfs) Primary OutFlow Max=0.00 cfs @ 0.00 hrs HW=42.00' (Free Discharge) 2=Broad-Crested Rectangular Weir ( Controls 0.00 cfs) NRCC 24-hr C 25-Year Rainfall=5.89"PR Printed 3/19/2024Prepared by VHB, Inc Page 30HydroCAD® 10.20-3c s/n 01038 © 2023 HydroCAD Software Solutions LLC Pond 1P: Infiltration Basin (Nature Depressed Area) Inflow Outflow Discarded Primary Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)0.09 0.085 0.08 0.075 0.07 0.065 0.06 0.055 0.05 0.045 0.04 0.035 0.03 0.025 0.02 0.015 0.01 0.005 0 Inflow Area=1.496 ac Peak Elev=43.01' Storage=161 cf 0.08 cfs 0.05 cfs 0.05 cfs 0.00 cfs NRCC 24-hr C 25-Year Rainfall=5.89"PR Printed 3/19/2024Prepared by VHB, Inc Page 31HydroCAD® 10.20-3c s/n 01038 © 2023 HydroCAD Software Solutions LLC Summary for Pond LB: Leaching Basins (3) Inflow Area = 0.237 ac, 81.43% Impervious, Inflow Depth = 4.41" for 25-Year event Inflow = 1.25 cfs @ 12.13 hrs, Volume= 0.087 af Outflow = 0.08 cfs @ 11.16 hrs, Volume= 0.087 af, Atten= 93%, Lag= 0.0 min Discarded = 0.08 cfs @ 11.16 hrs, Volume= 0.087 af Primary = 0.00 cfs @ 0.00 hrs, Volume= 0.000 af Routed to Link DP1 : Israel Pond Routing by Stor-Ind method, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs / 2 Peak Elev= 37.87' @ 13.47 hrs Surf.Area= 432 sf Storage= 1,536 cf Plug-Flow detention time= 150.8 min calculated for 0.087 af (100% of inflow) Center-of-Mass det. time= 150.7 min ( 952.2 - 801.5 ) Volume Invert Avail.Storage Storage Description #1 34.10' 551 cf 6.00'D x 6.50'H Leaching Basin x 3 Inside #2 #2 30.10' 1,698 cf 12.00'W x 36.00'L x 11.10'H Prismatoid 4,795 cf Overall - 551 cf Embedded = 4,244 cf x 40.0% Voids #3 40.60' 8 cf 2.00'D x 2.70'H Vertical Cone/Cylinder 2,257 cf Total Available Storage Device Routing Invert Outlet Devices #1 Device 3 42.10'10.0' long x 10.0' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 Coef. (English) 2.49 2.56 2.70 2.69 2.68 2.69 2.67 2.64 #2 Discarded 30.10'8.270 in/hr Exfiltration over Surface area #3 Primary 42.10'2.5" x 2.5" Horiz. Orifice/Grate X 6.00 columns X 6 rows C= 0.600 in 24.0" x 24.0" Grate (39% open area) Limited to weir flow at low heads #4 Primary 39.30'12.0" Round Outlet L= 5.0' RCP, rounded edge headwall, Ke= 0.100 Inlet / Outlet Invert= 39.30' / 39.00' S= 0.0600 '/' Cc= 0.900 n= 0.012, Flow Area= 0.79 sf Discarded OutFlow Max=0.08 cfs @ 11.16 hrs HW=30.24' (Free Discharge) 2=Exfiltration (Exfiltration Controls 0.08 cfs) Primary OutFlow Max=0.00 cfs @ 0.00 hrs HW=30.10' (Free Discharge) 3=Orifice/Grate ( Controls 0.00 cfs) 1=Broad-Crested Rectangular Weir ( Controls 0.00 cfs) 4=Outlet ( Controls 0.00 cfs) NRCC 24-hr C 25-Year Rainfall=5.89"PR Printed 3/19/2024Prepared by VHB, Inc Page 32HydroCAD® 10.20-3c s/n 01038 © 2023 HydroCAD Software Solutions LLC Pond LB: Leaching Basins (3) Inflow Outflow Discarded Primary Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)1 0 Inflow Area=0.237 ac Peak Elev=37.87' Storage=1,536 cf 1.25 cfs 0.08 cfs 0.08 cfs 0.00 cfs NRCC 24-hr C 25-Year Rainfall=5.89"PR Printed 3/19/2024Prepared by VHB, Inc Page 33HydroCAD® 10.20-3c s/n 01038 © 2023 HydroCAD Software Solutions LLC Summary for Link DP1: Israel Pond Inflow Area = 1.733 ac, 12.00% Impervious, Inflow Depth = 0.00" for 25-Year event Inflow = 0.00 cfs @ 0.00 hrs, Volume= 0.000 af Primary = 0.00 cfs @ 0.00 hrs, Volume= 0.000 af, Atten= 0%, Lag= 0.0 min Routed to nonexistent node 6L Primary outflow = Inflow, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs Link DP1: Israel Pond Inflow Primary Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)1 0 Inflow Area=1.733 ac 0.00 cfs 0.00 cfs NRCC 24-hr C 25-Year Rainfall=5.89"PR Printed 3/19/2024Prepared by VHB, Inc Page 34HydroCAD® 10.20-3c s/n 01038 © 2023 HydroCAD Software Solutions LLC Summary for Link DP2: Mary Dunn Road Drainage Inflow Area = 0.149 ac, 36.91% Impervious, Inflow Depth = 1.61" for 25-Year event Inflow = 0.29 cfs @ 12.14 hrs, Volume= 0.020 af Primary = 0.29 cfs @ 12.14 hrs, Volume= 0.020 af, Atten= 0%, Lag= 0.0 min Routed to nonexistent node 6L Primary outflow = Inflow, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs Link DP2: Mary Dunn Road Drainage Inflow Primary Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)0.3 0.28 0.26 0.24 0.22 0.2 0.18 0.16 0.14 0.12 0.1 0.08 0.06 0.04 0.02 0 Inflow Area=0.149 ac 0.29 cfs 0.29 cfs NRCC 24-hr C 100-Year Rainfall=7.83"PR Printed 3/19/2024Prepared by VHB, Inc Page 35HydroCAD® 10.20-3c s/n 01038 © 2023 HydroCAD Software Solutions LLC Time span=0.00-48.00 hrs, dt=0.03 hrs, 1601 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Runoff Area=0.237 ac 81.43% Impervious Runoff Depth=6.28"Subcatchment Mary Dunn - PR1: Subcat Tc=6.0 min CN=87 Runoff=1.75 cfs 0.124 af Runoff Area=1.024 ac 1.46% Impervious Runoff Depth=0.91"Subcatchment Mary Dunn - PR2: Subcat Tc=6.0 min CN=37 Runoff=0.70 cfs 0.078 af Runoff Area=0.149 ac 36.91% Impervious Runoff Depth=2.88"Subcatchment Mary Dunn - PR3: Subcat Tc=6.0 min CN=57 Runoff=0.53 cfs 0.036 af Runoff Area=0.472 ac 0.00% Impervious Runoff Depth=0.75"Subcatchment Mary Dunn - PR4: Subcat Tc=6.0 min CN=35 Runoff=0.20 cfs 0.029 af Peak Elev=45.75' Storage=1,463 cf Inflow=0.90 cfs 0.107 afPond 1P: Infiltration Basin (Nature Depressed Discarded=0.10 cfs 0.107 af Primary=0.00 cfs 0.000 af Outflow=0.10 cfs 0.107 af Peak Elev=39.55' Storage=1,910 cf Inflow=1.75 cfs 0.124 afPond LB: Leaching Basins (3) Discarded=0.08 cfs 0.110 af Primary=0.37 cfs 0.015 af Outflow=0.45 cfs 0.124 af Inflow=0.37 cfs 0.015 afLink DP1: Israel Pond Primary=0.37 cfs 0.015 af Inflow=0.53 cfs 0.036 afLink DP2: Mary Dunn Road Drainage Primary=0.53 cfs 0.036 af Total Runoff Area = 1.882 ac Runoff Volume = 0.267 af Average Runoff Depth = 1.70" 86.02% Pervious = 1.619 ac 13.98% Impervious = 0.263 ac NRCC 24-hr C 100-Year Rainfall=7.83"PR Printed 3/19/2024Prepared by VHB, Inc Page 36HydroCAD® 10.20-3c s/n 01038 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment Mary Dunn - PR1: Subcat Mary Dunn - PR1 Runoff = 1.75 cfs @ 12.13 hrs, Volume= 0.124 af, Depth= 6.28" Routed to Pond LB : Leaching Basins (3) Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs NRCC 24-hr C 100-Year Rainfall=7.83" Area (ac) CN Description 0.036 39 >75% Grass cover, Good, HSG A 0.193 98 Paved roads w/curbs & sewers, HSG A 0.008 30 Woods, Good, HSG A 0.237 87 Weighted Average 0.044 18.57% Pervious Area 0.193 81.43% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, min Subcatchment Mary Dunn - PR1: Subcat Mary Dunn - PR1 Runoff Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)1 0 NRCC 24-hr C 100-Year Rainfall=7.83" Runoff Area=0.237 ac Runoff Volume=0.124 af Runoff Depth=6.28" Tc=6.0 min CN=87 1.75 cfs NRCC 24-hr C 100-Year Rainfall=7.83"PR Printed 3/19/2024Prepared by VHB, Inc Page 37HydroCAD® 10.20-3c s/n 01038 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment Mary Dunn - PR2: Subcat Mary Dunn - PR2 Runoff = 0.70 cfs @ 12.15 hrs, Volume= 0.078 af, Depth= 0.91" Routed to Pond 1P : Infiltration Basin (Nature Depressed Area) Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs NRCC 24-hr C 100-Year Rainfall=7.83" Area (ac) CN Description 0.085 39 >75% Grass cover, Good, HSG A 0.128 76 Gravel roads, HSG A 0.796 30 Woods, Good, HSG A 0.015 98 Paved roads w/curbs & sewers, HSG A 1.024 37 Weighted Average 1.009 98.54% Pervious Area 0.015 1.46% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Min Subcatchment Mary Dunn - PR2: Subcat Mary Dunn - PR2 Runoff Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)0.75 0.7 0.65 0.6 0.55 0.5 0.45 0.4 0.35 0.3 0.25 0.2 0.15 0.1 0.05 0 NRCC 24-hr C 100-Year Rainfall=7.83" Runoff Area=1.024 ac Runoff Volume=0.078 af Runoff Depth=0.91" Tc=6.0 min CN=37 0.70 cfs NRCC 24-hr C 100-Year Rainfall=7.83"PR Printed 3/19/2024Prepared by VHB, Inc Page 38HydroCAD® 10.20-3c s/n 01038 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment Mary Dunn - PR3: Subcat Mary Dunn - PR3 Runoff = 0.53 cfs @ 12.13 hrs, Volume= 0.036 af, Depth= 2.88" Routed to Link DP2 : Mary Dunn Road Drainage Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs NRCC 24-hr C 100-Year Rainfall=7.83" Area (ac) CN Description 0.027 39 >75% Grass cover, Good, HSG A 0.055 98 Paved roads w/curbs & sewers, HSG A 0.067 30 Woods, Good, HSG A 0.149 57 Weighted Average 0.094 63.09% Pervious Area 0.055 36.91% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Min Subcatchment Mary Dunn - PR3: Subcat Mary Dunn - PR3 Runoff Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)0.55 0.5 0.45 0.4 0.35 0.3 0.25 0.2 0.15 0.1 0.05 0 NRCC 24-hr C 100-Year Rainfall=7.83" Runoff Area=0.149 ac Runoff Volume=0.036 af Runoff Depth=2.88" Tc=6.0 min CN=57 0.53 cfs NRCC 24-hr C 100-Year Rainfall=7.83"PR Printed 3/19/2024Prepared by VHB, Inc Page 39HydroCAD® 10.20-3c s/n 01038 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment Mary Dunn - PR4: Subcat Mary Dunn - PR4 Runoff = 0.20 cfs @ 12.16 hrs, Volume= 0.029 af, Depth= 0.75" Routed to Pond 1P : Infiltration Basin (Nature Depressed Area) Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs NRCC 24-hr C 100-Year Rainfall=7.83" Area (ac) CN Description 0.253 39 >75% Grass cover, Good, HSG A 0.218 30 Woods, Good, HSG A 0.472 35 Weighted Average 0.472 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, min Subcatchment Mary Dunn - PR4: Subcat Mary Dunn - PR4 Runoff Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)0.22 0.21 0.2 0.19 0.18 0.17 0.16 0.15 0.14 0.13 0.12 0.11 0.1 0.09 0.08 0.07 0.06 0.05 0.04 0.03 0.02 0.01 0 NRCC 24-hr C 100-Year Rainfall=7.83" Runoff Area=0.472 ac Runoff Volume=0.029 af Runoff Depth=0.75" Tc=6.0 min CN=35 0.20 cfs NRCC 24-hr C 100-Year Rainfall=7.83"PR Printed 3/19/2024Prepared by VHB, Inc Page 40HydroCAD® 10.20-3c s/n 01038 © 2023 HydroCAD Software Solutions LLC Summary for Pond 1P: Infiltration Basin (Nature Depressed Area) Inflow Area = 1.496 ac, 1.00% Impervious, Inflow Depth = 0.86" for 100-Year event Inflow = 0.90 cfs @ 12.16 hrs, Volume= 0.107 af Outflow = 0.10 cfs @ 12.33 hrs, Volume= 0.107 af, Atten= 89%, Lag= 10.4 min Discarded = 0.10 cfs @ 12.33 hrs, Volume= 0.107 af Primary = 0.00 cfs @ 0.00 hrs, Volume= 0.000 af Routed to Link DP1 : Israel Pond Routing by Stor-Ind method, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs Peak Elev= 45.75' @ 15.23 hrs Surf.Area= 521 sf Storage= 1,463 cf Plug-Flow detention time= 171.4 min calculated for 0.107 af (100% of inflow) Center-of-Mass det. time= 171.4 min ( 1,120.8 - 949.4 ) Volume Invert Avail.Storage Storage Description #1 42.00' 2,113 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 42.00 50 0 0 43.00 264 157 157 44.00 521 393 550 45.00 521 521 1,071 46.00 521 521 1,592 47.00 521 521 2,113 Device Routing Invert Outlet Devices #1 Discarded 42.00'8.270 in/hr Exfiltration over Surface area #2 Primary 46.90'10.0' long x 10.0' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 Coef. (English) 2.49 2.56 2.70 2.69 2.68 2.69 2.67 2.64 Discarded OutFlow Max=0.10 cfs @ 12.33 hrs HW=44.01' (Free Discharge) 1=Exfiltration (Exfiltration Controls 0.10 cfs) Primary OutFlow Max=0.00 cfs @ 0.00 hrs HW=42.00' (Free Discharge) 2=Broad-Crested Rectangular Weir ( Controls 0.00 cfs) NRCC 24-hr C 100-Year Rainfall=7.83"PR Printed 3/19/2024Prepared by VHB, Inc Page 41HydroCAD® 10.20-3c s/n 01038 © 2023 HydroCAD Software Solutions LLC Pond 1P: Infiltration Basin (Nature Depressed Area) Inflow Outflow Discarded Primary Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)1 0 Inflow Area=1.496 ac Peak Elev=45.75' Storage=1,463 cf 0.90 cfs 0.10 cfs 0.10 cfs 0.00 cfs NRCC 24-hr C 100-Year Rainfall=7.83"PR Printed 3/19/2024Prepared by VHB, Inc Page 42HydroCAD® 10.20-3c s/n 01038 © 2023 HydroCAD Software Solutions LLC Summary for Pond LB: Leaching Basins (3) Inflow Area = 0.237 ac, 81.43% Impervious, Inflow Depth = 6.28" for 100-Year event Inflow = 1.75 cfs @ 12.13 hrs, Volume= 0.124 af Outflow = 0.45 cfs @ 12.36 hrs, Volume= 0.124 af, Atten= 74%, Lag= 14.2 min Discarded = 0.08 cfs @ 10.74 hrs, Volume= 0.110 af Primary = 0.37 cfs @ 12.36 hrs, Volume= 0.015 af Routed to Link DP1 : Israel Pond Routing by Stor-Ind method, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs / 2 Peak Elev= 39.55' @ 12.36 hrs Surf.Area= 432 sf Storage= 1,910 cf Plug-Flow detention time= 173.1 min calculated for 0.124 af (100% of inflow) Center-of-Mass det. time= 173.2 min ( 963.9 - 790.7 ) Volume Invert Avail.Storage Storage Description #1 34.10' 551 cf 6.00'D x 6.50'H Leaching Basin x 3 Inside #2 #2 30.10' 1,698 cf 12.00'W x 36.00'L x 11.10'H Prismatoid 4,795 cf Overall - 551 cf Embedded = 4,244 cf x 40.0% Voids #3 40.60' 8 cf 2.00'D x 2.70'H Vertical Cone/Cylinder 2,257 cf Total Available Storage Device Routing Invert Outlet Devices #1 Device 3 42.10'10.0' long x 10.0' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 Coef. (English) 2.49 2.56 2.70 2.69 2.68 2.69 2.67 2.64 #2 Discarded 30.10'8.270 in/hr Exfiltration over Surface area #3 Primary 42.10'2.5" x 2.5" Horiz. Orifice/Grate X 6.00 columns X 6 rows C= 0.600 in 24.0" x 24.0" Grate (39% open area) Limited to weir flow at low heads #4 Primary 39.30'12.0" Round Outlet L= 5.0' RCP, rounded edge headwall, Ke= 0.100 Inlet / Outlet Invert= 39.30' / 39.00' S= 0.0600 '/' Cc= 0.900 n= 0.012, Flow Area= 0.79 sf Discarded OutFlow Max=0.08 cfs @ 10.74 hrs HW=30.24' (Free Discharge) 2=Exfiltration (Exfiltration Controls 0.08 cfs) Primary OutFlow Max=0.35 cfs @ 12.36 hrs HW=39.55' (Free Discharge) 3=Orifice/Grate ( Controls 0.00 cfs) 1=Broad-Crested Rectangular Weir ( Controls 0.00 cfs) 4=Outlet (Inlet Controls 0.35 cfs @ 2.30 fps) NRCC 24-hr C 100-Year Rainfall=7.83"PR Printed 3/19/2024Prepared by VHB, Inc Page 43HydroCAD® 10.20-3c s/n 01038 © 2023 HydroCAD Software Solutions LLC Pond LB: Leaching Basins (3) Inflow Outflow Discarded Primary Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)1 0 Inflow Area=0.237 ac Peak Elev=39.55' Storage=1,910 cf 1.75 cfs 0.45 cfs 0.08 cfs 0.37 cfs NRCC 24-hr C 100-Year Rainfall=7.83"PR Printed 3/19/2024Prepared by VHB, Inc Page 44HydroCAD® 10.20-3c s/n 01038 © 2023 HydroCAD Software Solutions LLC Summary for Link DP1: Israel Pond Inflow Area = 1.733 ac, 12.00% Impervious, Inflow Depth = 0.10" for 100-Year event Inflow = 0.37 cfs @ 12.36 hrs, Volume= 0.015 af Primary = 0.37 cfs @ 12.36 hrs, Volume= 0.015 af, Atten= 0%, Lag= 0.0 min Routed to nonexistent node 6L Primary outflow = Inflow, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs Link DP1: Israel Pond Inflow Primary Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)0.4 0.38 0.36 0.34 0.32 0.3 0.28 0.26 0.24 0.22 0.2 0.18 0.16 0.14 0.12 0.1 0.08 0.06 0.04 0.02 0 Inflow Area=1.733 ac 0.37 cfs 0.37 cfs NRCC 24-hr C 100-Year Rainfall=7.83"PR Printed 3/19/2024Prepared by VHB, Inc Page 45HydroCAD® 10.20-3c s/n 01038 © 2023 HydroCAD Software Solutions LLC Summary for Link DP2: Mary Dunn Road Drainage Inflow Area = 0.149 ac, 36.91% Impervious, Inflow Depth = 2.88" for 100-Year event Inflow = 0.53 cfs @ 12.13 hrs, Volume= 0.036 af Primary = 0.53 cfs @ 12.13 hrs, Volume= 0.036 af, Atten= 0%, Lag= 0.0 min Routed to nonexistent node 6L Primary outflow = Inflow, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs Link DP2: Mary Dunn Road Drainage Inflow Primary Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)0.55 0.5 0.45 0.4 0.35 0.3 0.25 0.2 0.15 0.1 0.05 0 Inflow Area=0.149 ac 0.53 cfs 0.53 cfs Recharge Calculations Project Project # Calculated by Date Checked by Date REQUIRED RECHARGE VOLUME CAPTURE AREA ADJUSTMENT Required Recharge Volume (ft3)565 Total Site Net Impervious Area (ft2)11,309 Total Site Impervious Area Draining to Recharge Facilities (ft2)9,634 Capture Area Adjustment Factor 1.17 Adjusted Required Recharge Volume (ft3)664 BASIN #1: Three (3) Leaching Basins in crushed stone at the rear of Mary Dunn Rd. Parking Lot Volumes provided below the lowest outlet at elevation:39.30 Provided Volume: Drawdown:(VInfiltration/ABottom)/Rawl's Rate Rawls Recharge Rate:(in/hr) Drawdown Time:(hours) RECHARGE VOLUME SUMMARY Required Recharge Volume:(ft3) Total Recharge Volume Provided:(ft3)2,254 664 8.27 8 30.1 432 0 39.3 432 2,254 TOTAL 565 Elevation Area Cumulative Volume (ft2) (ft 3) C 0 0.25 0 D 0 0.10 0 A 11,309 0.60 565 B 0 0.35 0 EJM 3/19/2024 Hydrologic Soil Group (HSG) Area Inches of Runoff Volume (ft2)(in)(ft3) Cape Cod Rail Trail 12811.01 AEG 3/19/2024 \\vhb\gbl\proj\Wat-TE\12811.01\tech\Stormwater\Recharge & Drawdown Calculations 1 of 1 Water Quality Volume Calculations Project Project # Calculated by Date Checked by Date Runoff from subcatchment area Mary Dunn Rd. Water Quality Storm Runoff Depth (in) Total Impervious Area (ft2) STORMCEPTOR WQV: *Refer to Stormceptor sizing output LEACHING BASIN WQV: System consists of 3 6' Dia leaching basins embedded in crushed stone Required Volume: Provided Volume: * Per MassDEP Treatment Requirement ** Based on Stage Storage Output from HydroCAD 030.1 432 39.3 432 1863** 1.0 942 Elevation Area Cumulative Volume (ft2) (ft 3) (in) (ft 3) Required VolumeRunoff Depth to be Treated EJM 3/19/2024 11,309 1.0 Cape Cod Rail Trail 12811.01 AEG 3/19/2024 \\vhb\gbl\proj\Wat-TE\12811.01\tech\Stormwater\Water Quality Volume Calculations 1 of 1 TSS Removal Calculation Worksheet Project Name:Cape Cod Rail Trail Sheet:1 of 4 Project Number:12811.01 Date:19-Mar-2024 Location:Barnstable and Yarmouth, MA Computed by:RPL Discharge Point:Israel Pond Checked by:EJM Drainage Area(s):Mary Dunn -PR1 1. Pre-Treatment prior to Infiltration BMP* TSS Removal Rate* Starting TSS Load** Amount Removed (C*D) Remaining Load (D-E) Deep Sump and Hooded Catch Basin 25% 100% 25% 75% Stormceptor 90% 75% 68% 8% 0% 8% 0% 8% 93% 2. Total TSS Removal including Pretreatment 1. BMP* TSS Removal Rate* Starting TSS Load** Amount Removed (C*D) Remaining Load (D-E) Leaching Catch Basin 80% 100% 80% 20% 0% 20% 0% 20% 0% 20% 0% 20% 0% 20% 0% 20% Treatment Train TSS Removal =80% Pre-Treatment TSS Removal = * BMP and TSS Removal Rate Values from the MassDEP Stormwater Handbook Vol. 1. Removal rates for proprietary devices are from approved studies and/or manufacturer data (attach study or data source, or remove this sentence if not applicable). ** Equals remaining load from previous BMP (E) *** Stormceptor sizing calculation gives a TSS removal rate of 87%. To be conservative, 80% removal is used for this calculation (Change name of device and the claimed removal rate shown on the calc. sheet. Remove this sentence if not applicable. 101 Walnut Street Post Office Box 9151 Watertown, MA 02471 P 617.924.1770 \\vhb\gbl\proj\Wat-TE\12811.01\tech\Stormwater\TSS Removal Calculations Project Information & Location Project Name CCRT Phase III Project Number 12811.01 City Barnstable State/ Province Massachusetts Country United States of America Date 6/26/2023 Designer Information EOR Information (optional) Name Rachel Luna Name Company VHB Company Phone #781-752-7122 Phone # Email rluna@vhb.com Email Brief Stormceptor Sizing Report - CCRT Phase III Site Name Target TSS Removal (%)80 TSS Removal (%) Provided 90 Recommended Stormceptor Model STC 450i Stormceptor Sizing Summary Stormceptor Model % TSS Removal Provided STC 450i 90 STC 900 94 STC 1200 94 STC 1800 94 STC 2400 96 STC 3600 96 STC 4800 97 STC 6000 97 STC 7200 98 STC 11000 99 STC 13000 99 STC 16000 99 The recommended Stormceptor Model achieves the water quality objectives based on the selected inputs, historical rainfall records and selected particle size distribution. Stormwater Treatment Recommendation The recommended Stormceptor Model(s) which achieve or exceed the user defined water quality objective for each site within the project are listed in the below Sizing Summary table. Stormceptor Brief Sizing Report ±Page 1 of 2 Notes Stormceptor performance estimates are based on simulations using PCSWMM for Stormceptor, which uses the EPA Rainfall and Runoff modules. Design estimates listed are only representative of specific project requirements based on total suspended solids (TSS) removal defined by the selected PSD, and based on stable site conditions only, after construction is completed. For submerged applications or sites specific to spill control, please contact your local Stormceptor representative for further design assistance. Drainage Area Total Area (acres)0.24 Imperviousness %80.8 Water Quality Objective TSS Removal (%)80.0 Runoff Volume Capture (%) Oil Spill Capture Volume (Gal) Peak Conveyed Flow Rate (CFS) Water Quality Flow Rate (CFS) Rainfall Station Name HYANNIS State/Province Massachusetts Station ID #3821 Years of Records 14 Latitude 41°24'0"N Longitude 70°10'47"W Up Stream Storage Storage (ac-ft)Discharge (cfs) 0.000 0.000 Particle Size Distribution (PSD) The selected PSD defines TSS removal Fine Distribution Particle Diameter (microns) Distribution % Specific Gravity 20.0 20.0 1.30 60.0 20.0 1.80 150.0 20.0 2.20 400.0 20.0 2.65 2000.0 20.0 2.65 Up Stream Flow Diversion Max. Flow to Stormceptor (cfs) Sizing Details For Stormceptor Specifications and Drawings Please Visit: https://www.conteches.com/technical-guides/search?filter=1WBC0O5EYX Stormceptor Brief Sizing Report ±Page 2 of 2 \\vhb\gbl\proj\Wat-TE\12811.01\docs\memos\Stormwater Memo\12811.01 - Stormwater Memo.docx Attachment D Operation and Maintenance Plan and Long-Term Pollution Prevention Plan ◼ Page | 1 Cape Cod Rail Trail Phase III Barnstable, Massachusetts Stormwater Management System Operation and Maintenance Plan (O&M) and Long-Term Pollution Prevention Plan (LTPPP) March 2024 This Stormwater Management System Operation and Maintenance (O&M) Plan provides for the inspection and maintenance of structural Best Management Practices (BMPs) and for measures to prevent pollution associated with the stormwater management system proposed for the Cape Cod Rail Trail Phase III project in the Town of Barnstable. This document has been prepared in accordance with the requirements of the Stormwater Regulations included in the Massachusetts Wetlands Protection Act Regulations (310 CMR 10). Responsible Party The Town of Barnstable Public Works Department will be responsible for the maintenance of the roadway facilities and associated stormwater management features, in accordance with Town standards. Questions or concerns regarding maintenance activities may also be addressed to Town of Barnstable Public Works Department: Public Works Department 382 Falmouth Road Hyannis, MA 02601 Phone: (508)-790-6400 Maintenance Measures The stormwater management system covered by this Operation and Maintenance Plan consists of the following components: · Deep-Sump, Hooded Catch Basins · Leaching Basins · Stormceptor Page | 2 Maintenance of these components will be conducted in accordance with Town of Barnstable Public Works Department standard maintenance practices, as noted in the attached Operation and Maintenance table summarizing the pertinent inspection and maintenance activities. If inspection indicates the need for major repairs of structural surfaces, the inspector should contact the Town of Barnstable Public Works Department to initiate procedures to effect repairs in accordance with Town of Barnstable Public Works Department standard construction practices. Practices for Long-Term Pollution Prevention For the facilities covered by this Operation and Maintenance Plan, long-term pollution prevention includes the following measures: Litter Pick-up The Town of Barnstable Public Works Department will conduct litter pick-up from the stormwater management facilities in conjunction with routine road maintenance activities. Routine Inspection and Maintenance of Leaching Basins The Town of Barnstable Public Works Department will conduct inspection and maintenance of the stormwater management practices in accordance with the information in Table 1. Maintenance of Landscaped Areas Routine mowing should be conducted according to standard Town of Barnstable Public Works Department practices. Town of Barnstable Public Works Department shall minimize use of fertilizers, herbicides, and pesticides for the maintenance of facilities covered by this plan. Use of fertilizers, herbicides, or pesticides may need to be reviewed and approved by the local Conservation Commission. Snow and Ice Management Snow and Ice Management shall be conducted according to standard Town of Barnstable Public Works Department practices. Prohibition of Illicit Discharges The DEP Stormwater Management Standards prohibit illicit discharges to the storm water management system. Illicit discharges are discharges that do not entirely consist of stormwater, except for certain specified non-stormwater discharges. Discharges from the following activities are not considered illicit discharges: firefighting foundation drains water line flushing footing drains landscape irrigation individual resident car washing uncontaminated groundwater flows from riparian habitats and wetlands potable water sources dechlorinated water from swimming pools water used to clean residential buildings without detergents water used for street washing air conditioning condensation Page | 3 There are no known or proposed illicit connections associated with this project. If a potential illicit discharge to the facilities covered by this plan is detected (e.g., dry weather flows at any pipe outlet, evidence of contamination of surface water discharge by non-stormwater sources), the Town of Barnstable Public Works Department shall be notified for assistance in determining the nature and source of the discharge, and for resolution through the Highway Department’s IDDE program. Table 1: Best Management Practices: Operation & Maintenance Measures Best Management Practice Sweep Mow Inspect Clean Repair Street Sweeping Annually NA NA NA NA Deep-Sump, Hooded Catch Basins NA NA Annually ANI ANI Leaching Basins NA NA Annually ANI ANI Stormceptor NA NA Annually ANI ANI NA = Not Applicable ANI = As needed based on inspection Notice of Intent Attachment E: Notice of Intent Plans › Bound Separately