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HomeMy WebLinkAboutBarnstable Straightway NOI_12.23.2024_Narrative ATTACHMENT A NOI Narrative ____________________________________________________________________________ NOI: Straightway and Hyannisport Water Treatment Facilities Improvements Page 1 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), as well as in accordance with the Town of Barnstable (Town) Wetlands Protection Bylaw and Regulations (Chapter 237-Bylaw; Part VII-Regulations). This narrative presents regulated resource areas associated with the Town of Barnstable’s (Town) Straightway and Hyannisport Water Treatment Facility Improvements Project (Project) area, a description of the proposed work, proposed mitigation measures, and how the Project meets the performance standards of the WPA regulations. Refer to the accompanying Project plans included as Attachment B for a plan layout and details of the Project components. Introduction The Town of Barnstable proposes improvements to the Hyannis Water System’s (HWS) existing water infrastructure located at 228 Straightway, 132 Smith Street, and 0 Old School House Road in Barnstable (Project). Improvements are needed to restore supply, pumping, and treatment capacity, as well as to improve resiliency for meeting current and future conditions. The HWS operates three drinking water treatment complexes with a total of 12 wells and serves a year-round population of approximately 18,000 people which surges to about 35,000 in the summer. Recent summer demand has hit record highs, and without proposed improvements, all wells and treatment facilities must pump continuously in summer. The Project will provide a public health benefit and improve the drinking water quality, reliability, and resiliency of the Town of Barnstable’s HWS. All of the HWS’s wells are impacted by per- and poly-fluoroalkyl substances (PFAS) contamination and are treated to remove PFAS. However, some wells which lack winterized equipment must be turned off during winter. Beginning in 2016, when the US Environmental Protection Agency’s (EPA’s) PFAS Health Advisory was lowered from 300 to 70 nanograms per liter (ng/L), the Town voluntarily and rapidly implemented emergency seasonal PFAS treatment by installing unwinterized granular activated carbon (GAC) filter units. The PFAS removal system at the Maher water treatment facility has been fully winterized and the PFAS removal system at the Mary Dunn water treatment facility has been partially winterized to allow for year-round operation. However, the Straightway and Hyannisport Treatment Facilities (the Project site – See Figure 1 Site Location and Figure 2 Site Plan) need improvements to winterize existing PFAS units, as well as to restore well yield, maximize permitted pumping capacity and increase treatment capacity, to improve overall system resiliency, resiliency to sea level rise, and reliably meet current and future drinking water regulations. Proposed work for the Project would occur within the following WPA regulated resources: 100 -foot Wetland Buffer Zone, and 200-foot Riverfront Area. Work will also occur with the 50-foot Wetland Buffer Zone. The Project meets or exceeds all performance standards for these resources under the WPA and Part 7 of the Town of Barnstable General Ordinances. NOI: Straightway and Hyannisport Water Treatment Facilities Improvements Page 2 Site Description and Existing Conditions The Project is located on two separate complexes, approximately 1,700 feet apart, and are connected by a dirt access road, with the Straightway Complex located to the north at 228 Straightway and the Hyannisport Complex located to the south at 132 Smith Street and 0 Old School House Road. The work proposed is included on the following parcels within the Village of Hyannis: Table 1. Project Parcels Address Parcel Numbers Registry of Deeds Book & Page # Registered Land 0 Old Schoolhouse Rd 267-190 Book 19847 Page 0223 Cert. Title 176756; Lot 4 on Land Court Plan 36483-B 132 Smith St. 267-099 Book 19847 Page 0223 N/A 228 Straightway 268-099 Book 19847 Page 0223 N/A The Straightway and Hyannisport Treatment Complexes are a critical HWS component. They are located on developed open space on approximately 48 acres of protected water supply land (see Figure 2, Site Plan and Figure 3, Project Area Land Use). The facilities consist of four wells, five pumping and/or treatment buildings (totaling 7,639 square feet), four unwinterized PFAS filters, and a 400,000 -gallon storage tank. The existing facility structures are shown on photographs included as Figure 4. The Straightway Complex includes Straightway Well 1 and Straightway Well 2 on the north complex. The Hyannisport Complex includes the Hyannisport and Simmons Pond wells. See Figure 2, Site Plan. The Straightway Complex is primarily developed open space and deciduous forest. Impervious surfaces within the developed open space consist of the existing buildings, water storage tank, and access roadways. The Hyannisport Complex is primarily deciduous forest with a small area of developed open space; impervious surfaces consist of the existing buildings and access roadways. Land use data (Figure 3) was obtained from the “2016 Land Cover/Use” layer in the Massachusetts Bureau of Geographic Information (MassGIS), MassMapper application. The project site is primarily deciduous forest (2.01 acres) and developed open space (1.51 acres). Additional land uses at the site include grassland (0.29 acres), palustrine forested wetland (0.15 acre), and evergreen forest (0.07 acre). The site currently includes 0.73 acres of impervious area within the developed open space. Regulated Resource Areas According to the most recently available data provided by the Massachusetts Natural Heritage and Endangered Species Program (NHESP), no Priority Habitats for Rare Species or Estimated Habitats for Rare Wildlife have been mapped in the vicinity of the Project area. No certified or potential vernal pools have been mapped in the Project area. The Project area is not located within or near an Area of Critical Environmental Concern (ACEC) or an Outstanding Resource Water area (See Figure 5 – Environmental Constraints). According to the FEMA Flood Insurance Rate Map for Barnstable County, Map Number 25001C0568J, effective July 16, 2014, the Hyannisport Site Project area is partially located in Zone X, which is classified as areas within the 0.2% Annual Chance Flood Hazard (500-year flood) and areas of minimal flooding outside the 0.2% Annual Chance NOI: Straightway and Hyannisport Water Treatment Facilities Improvements Page 3 Floodplain (See Figure 6 – FEMA Map). No areas of the project site fall within the 100-year floodzone and therefore Bordering Land Subject to Flooding is not present at the Project sites. Wetland resources delineation of the Project area was performed by Lucas Environmental, LLC (Lucas) on November 29, 2023. The following regulated wetland resource areas are within the Halls Creek Watershed and are jurisdictionally impacted by the proposed project activity: • Hyannisport Site: Resources impacted by the project include bordering vegetated wetlands (BVW) of Simmons Pond and river front area associated with Halls Creek and an unnamed tributary to Halls Creek. • Straightway Site: Resources impacted by the project include BVW associated with Ben's Pond and with an unnamed marsh east of the existing Straightway facility. For additional information on wetland boundaries and conditions, see Attachment C, Wetlands Summary Letter (dated January 30, 2024). A brief description of each resource is provided below. Simmons Pond and Bordering Vegetated Wetlands Simmons Pond is an 8.4-acre open water body located to the east of the Hyannisport Treatment Complex. Bordering Vegetated Wetlands associated with Simmons Pond corresponds to Lucas delineated Wetland Area B, as identified by the wetland flag WF-B series. The pond is immediately surrounded by shrub swamp and wooded swamp. The existing Simmons Pond Pump Station is within the Town of Barnstable 50-ft wetland buffer of Area B. The proposed Simmons Pond Replacement Well and Pump Station will be relocated outside of the 50-foot wetland buffer. The existing Hyannisport Well and Treatment Facility is within the 100-ft wetland buffer and partially within the 100-ft Riverfront area of Halls Creek and its unnamed tributary. The existing Hyannisport facility access road and parking area is also within the 50-ft wetland buffer of Wetland B. The proposed Hyannisport Replacement Well and Pump Station will be further upgradient out of the inner 100-ft Riverfront but still within the 200 Riverfront and the 100-foot wetland buffer, with parking and access road by necessity still within the 50-ft buffer. Once existing pump stations are relocated, the old structures and pavement will be demolished and reseeded with a native wetland seed mix, as shown on the Plans. Halls Creek and Unnamed Tributary to Halls Creek Halls Creek drains Simmons Pond at its southerly end and an unnamed tributary to Halls Creek is located southwest of the existing Hyannisport Facility and drains to the southeast into Halls Creek. Lucas delineated the Bank of both Halls Creek and tributary, as well as BVW Wetland Area A associated with the unnamed tributary. The existing Hyannisport Well and Treatment Facility is partially within the 100-ft Riverfront area of Halls Creek and its unnamed tributary. The proposed Hyannisport Pump Station will be located within the 200-foot Riverfront Area. Ben’s Pond Ben’s Pond is a 4.97-acre open water body to the north of the Straightway Treatment Complex. Bordering Vegetated Wetland associated with Ben’s Pond corresponds to delineated Wetland C. The existing Straightway Treatment Facility is partially within the 100-foot wetland buffer of this pond’s adjacent wetlands. The existing gas main and water main for the Straightway Treatment Complex run through both the 50 -foot and 100-foot NOI: Straightway and Hyannisport Water Treatment Facilities Improvements Page 4 buffers of the Ben’s Pond wetlands. Proposed work within the 100-foot wetland buffer will include capping the existing water main and abandoning it in place, installing a replacement water main outside of the 50-foot wetland buffer, installing additional electrical and gas lines to service the new treatment building, restoring existing pavement disturbed for the proposed utility work, and paving as part of a new access road to the new treatment facility. Unnamed Marsh There is an unnamed marsh to the east of the Straightway Treatment Complex, also corresponding to Wetland C. A short length of existing below grade electrical lines exists within the 100-foot buffer of this wetland. Proposed work in the 100-foot buffer zone includes tree clearing and re-grading for storm water management. Once re- grading occurs, the area will be replanted with native vegetation. Proposed Activities The proposed Project design is for a new centralized Straightway Water Treatment Facility (SWTF) located at the 228 Straightway site, which will treat water originating from the four wells by utilizing the following technologies: • Five 12-foot greensand filtration units for iron and manganese removal, thus eliminating the need for sequestering agents currently added at the individual wells. • Eight additional GAC filtration units for PFAS removal. • A UV-AOP treatment system for the destruction of 1,4-dioxane. • Chemical treatment for corrosion control, pH adjustment, and disinfection. Additional proposed infrastructure upgrades at the Straightway Site include: • Upgrades to the existing booster pump station to increase capacity to 4 MGD and modifications to the disinfection contact time (CT) approach. • Winterization of existing GAC filters. • Upgrades to both the Straightway 1 and Straightway 2 well pumps to accommodate the additional head imposed by new treatment processes (the existing Straightway Treatment Facility housing both wells will remain in place). The offline Straightway well will be reactivated. • Filling in of the existing unlined backwash lagoon and installation of a new backwash waste holding tank below the proposed treatment facility building. • New tight tanks proposed for collecting and containing wastewater generated onsite and backwash tank for greensand/GAC. At the Hyannisport Site accessed via 132 Smith Street, the proposed work consists of the replacement of the Hyannisport and Simmons Ponds wells, pumps, and pump stations. NOI: Straightway and Hyannisport Water Treatment Facilities Improvements Page 5 Following the construction, testing, MassDEP acceptance, and startup of the new facilities, the existing Straightway building chemical feed systems will be decommissioned, but the building will remain since it houses the Straightway 1 and Straightway 2 Wells. The existing Hyannisport Well and Simmons Pond Wells will be abandoned in accordance with MassDEP guidelines and the existing Hyannisport and Simmons Pond facilities will be demolished. Following demolition of buildings and un-used paved areas, the land will be restored with native wetland seedmix. The selected site layout includes a 113-foot x 87-foot SWTF building on the south side of the Straightway Treatment Complex, directly south of the existing water storage tank. This location allows an infiltration basin for stormwater management to be installed at the north side of the Straightway Complex where sheetflow runoff is naturally directed. A looped access drive is provided for usage by equipment and chemical delivery trucks. This alternative also provides adequate available space to the north for future Straightway Well 1 and Straightway Well 2 replacement within the 250-foot maximum well replacement radii, in accordance with MassDEP’s Guidelines for Public Water Systems. This location requires clearing of some existing trees and vegetation and additional paving around the building to provide access for fire trucks in cases of emergency as well as chemical and equipment deliveries. It will also provide access to the existing Hyannisport and Simmons Pond access drive. See Project Plans in Attachment B. The existing backwash lagoon will be backfilled with common fill or structural fill, as indicated in the construction drawings. New evergreen tree screening will be provided between the new facilities and the abutting residential properties. Summary of Resource Area Impacts and WPA Compliance Proposed work for the Project would occur within the following WPA regulated resources: 100 -foot Buffer Zone and 200-foot Riverfront Area. Work will also occur within the 50-foot Town of Barnstable Wetland Buffer Zone. The Project meets or exceeds all performance standards for these resources under the WPA and the Town of Barnstable Wetlands Protection Ordinance and Regulations. Resource impacts and compliance with the applicable performance standards for each resource are described in more detail below. Construction of the Project will occur near wetlands, with some activities occurring within the 50-foot wetlands buffer zone, 100-foot wetlands buffer zone, and within 200-foot riverfront areas. This project is expected to have a number of beneficial impacts on nearby wetlands. The Simmons Pond Pump station will be moved outside of the 50-foot wetland buffer and the existing location will be restored native plants. The existing Hyannis Treatment Facility, which is within the 100-foot wetlands buffer and within the 100-ft Riverfront Area will also be replaced further upgradient- removing the structure from the 100-ft Riverfront. To the extent feasible the old location will be restored with native seed mix.. The extent of the wetlands impact of the Project are summarized in the table below. NOI: Straightway and Hyannisport Water Treatment Facilities Improvements Page 6 Table 2. Wetlands Impact Summary Resource Area Temporary Impact (square feet) Permanent Impact (square feet) 50-foot Wetland Buffer 19,664 2,376 100-foot Wetland Buffer 51,933 19,199 200-foot Riverfront Area 15,805 4,136 At the Hyannisport Treatment Complex, temporary wetland impacts within the 50-foot wetlands buffer consist of repaving the existing road. Permanent impacts consist of installation of fencing, tree clearing, proposed paving work, the demolition of the existing Simmons Pond Pump station, and restoration of the demolition area with native vegetation. Additional work within the 100-foot wetland buffer includes the demolition of the existing Hyannisport treatment facility and the construction of the new Hyannisport and Simmons Pond Pump Stations. At the Straightway Treatment Complex, temporary work within the 50-foot buffer consists of repaving the existing roadway after utilities installation. Additional permanent work within the 100-foot wetland buffer consists of utilities installation, access road re-configuration and paving, tree clearing, and stormwater management basin installation. Potential negative construction phase impacts on surrounding wetlands include sedimentation from construction activities, including dewatering, flowing into the resource areas. To mitigate sedimentation and erosion impacts, the Project will implement sedimentation and erosion controls such as silt sacks or wattles. Following construction, temporarily disturbed areas will be restored with appropriate native seed mixes. 310 CMR 10.02(2)(b) and Town of Barnstable Wetland Buffer Zones In general, work within a Buffer Zone is permissible when said work has been designed, or can be conditioned, such that there will be no impact on the downgradient wetland resource area(s) being buffered. As stated in 310 CMR 10.53(1) of the WPA Regulations: For work in Buffer Zone subject to review under 310 CMR 10.02(2)(b)3., the Issuing Authority shall impose conditions to protect the interests of the Act identified for the adjacent Resource Area… The issuing authority may 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 work with the Buffer Zone to protect the interests of the Act. The Town of Barnstable General Ordinance, Chapter 704: Regulation Governing Activity in the 100-ft. Buffer Zone implements additional wetlands protection by maintaining a uniform provision of an undisturbed buffer zone width of 50 feet from a wetland resource. Measures have been incorporated into the Project design to ensure that work will be done in a manner that prevents impacts to downgradient wetland resources. A clear limit of work will be identified, and erosion and NOI: Straightway and Hyannisport Water Treatment Facilities Improvements Page 7 sedimentation control areas will be established in the Project area. Temporary disturbance in vegetated areas of Buffer Zone will be restored in place and seeded following completion of construction. Riverfront Area The general performance standards for riverfront area set forth in 301 CMR 10.58(4) are: Where the presumption set forth in 310 CMR 10.58(3) is not overcome, the applicant shall prove by a preponderance of the evidence that there are no practicable and substantially equivalent economic alternatives to the proposed project with less adverse effects on the interests identified in M.G.L. c.131 § 40 and that the work, including proposed mitigation, will have no significant adverse impact on the riverfront area to protect the interests identified in M.G.L. c. 131 § 40. In the event that the presumption is partially overcome, the issuing authority shall make a written determination setting forth its grounds in the Order of Conditions and the partial rebuttal shall be taken into account in the application of 310 CMR 10.58 (4)(d)1.a. and c.; the issuing authority shall impose conditions in the Order that contribute to the protection of interests for which the riverfront area is significant. The Project was designed to address the performance standards identified in 310 CMR 10.58(4) for the work conducted in Riverfront Area. As demonstrated in the “Alternatives Analysis” section below, the chosen alternative results in a shorter construction period and a lower environmental impact, due to the smaller building footprint, reduced tree clearing, and minimized work in the wetland buffer zone. Furthermore, the chosen alternative provides greater protection from flooding for critical infrastructure. The Project also meets performance criteria for other regulated resources and therefore satisfies all performance standards for Riverfront Area. Compliance with Massachusetts Storm Water Policy Runoff generated from impervious surfaces will be collected and managed in accordance with the DEP Stormwater policies and Town of Barnstable Stormwater Management Bylaw. As no stormwater management is currently present at either site, this is a significant improvement to existing conditions. The proposed Project will improve existing conditions within the Project Area by constructing a stormwater management system that includes measures to provide groundwater recharge, attenuate peak flows, and provide water quality treatment. Full details on the system (including supporting calculations) are included in the accompanying Stormwater Management Report, Attachment D. Compliance with the 10 stormwater management standards cited in Section 310 CMR 10.05(6)(k) of the WPA Regulations is evaluated in the Stormwater Management Standards section of the Stormwater Management Report. Alternative Analysis Based upon the presence of Riverfront Area in the Project Area, the Project proponent performed an alternatives analysis, as described below. This alternatives analysis considers the potential environmental impacts of different build scenarios compared to the no-build condition as a baseline. Additionally, this alternatives analysis considers whether any alternative exists that effectively achieves the Project goal of improving drinking water quality at the Straightway and Hyannisport sites with lesser impact than the selected build alternative. NOI: Straightway and Hyannisport Water Treatment Facilities Improvements Page 8 No Build The “No Build” alternative includes no well improvements or treatment facility upgrades. At present, all four wells treated at this site have PFAS concentrations above the existing Massachusetts and federal drinking water regulations. Without additional treatment, HWS is limited to a summertime capacity of 5.04 MGD. In 2022, the HWS had a maximum daily demand (MDD) of 5.3 MGD, a new historic maximum. As a result, all wells and treatment infrastructure must pump continuously in the summer. If a treatment facility fails or experiences any issues, the system may not be able to meet demand. Operating so close to capacity in the summer months is an unacceptable option and the No Build alternative was deemed unfeasible. Furthermore, if the Hyannisport and Simmons Pond wells are not relocated, HWS critical infrastructure will remain within the 500-year floodplain and near wetland resources. This increases the system’s susceptibility to flooding. Off-Site Alternative No locations outside of the current project site were considered for the Project. There is no feasible off-site alternative that would result in a lower environmental impact. Installation of water mains from the well locations to an off-site treatment plant is cost prohibitive, disruptive to local residents, including nearby EJ populations, and greatly increases the project footprint. There is no available open Town-owned land suitable for water supply development which could be implemented in a short time frame. The following alternatives for treatment options onsite were evaluated as part of the alternatives analysis. Two-Plant Alternative In November 2021, Kleinfelder produced a Piloting Report titled, “Pilot Study Report: Straightway and Hyannisport Facilities Hyannis Water System” (Kleinfelder), which evaluated a two-plant alternative for the Project and was developed to maximize overall firm yield. The two-plant alternative consisted of one new treatment facility at the Straightway Complex to treat water from Straightway 1 and Straightway 2 wells and one new treatment facility at the Hyannisport Complex to treat water from the Hyannisport and Simmons Pond wells. In this alternative, both treatment facilities would include greensand filtration, UV-AOP treatment, GAC filtration units, and chemical injection for pH, corrosion control, and chlorination. This alternative required the installation of either a tank or a contact loop at the Hyannisport Treatment Facility to achieve the required contact time. The major benefit of the two-plant alternative was that it provided additional resiliency in the case that one of the two treatment plants failed. Major downsides to the alternative included a much higher construction and operating cost and a larger environmental impact. Constructing two buildings increased the overall building footprint for the Project and would have required additional tree clearing. Furthermore, the Hyannisport treatment facility would have encroached on the nearby wetlands buffer zone and been at an increased flood risk compared to the Straightway plant location. Single Plant – Selected Build Alternative In May 2023, Kleinfelder published an update to the Piloting Report, titled, “Update to November 2021 Pilot Study Report: Straightway & Hyannisport Evaluation of Single Plant Option” (Kleinfelder). In this update, the single plant alternative was evaluated as a second construction alternative. It consists of a single treatment plant at the NOI: Straightway and Hyannisport Water Treatment Facilities Improvements Page 9 Straightway Complex, along with the well and pump station replacements proposed at the Hyannisport site. Treatment at the plant includes greensand filtration, UV-AOP, GAC filtration units, and chemical injection for pH, corrosion control, and chlorination. The plant design re-uses the existing GAC filters that are already onsite at the Complex and adds additional GAC filtration to treat the entire permitted value for the four wells at the new facility. Major benefits of this design include a lower construction cost, shorter construction period, and a lower environmental impact, due to the smaller building footprint, reduced tree clearing, and minimized work in the wetland buffer zone. Furthermore, this alternative provides greater protection from flooding for critical infrastructure. The RMAT analysis tool found that the project site was at high risk of coastal and precipitation event flooding as a result of climate change. Moving all treatment equipment to a higher elevation site protects the critical infrastructure from future threats. For these reasons, the Single Plant Alternative is the chosen alternative. Mitigation The Project is expected to have positive environmental and public health impacts. Primary beneficial environmental impacts of the Project include the relocation of critical infrastructure from wetland and riverfront resources to outside of the 50-ft buffer of BVW and the 500-year floodplain, restoration of land within the 500- year floodplain and 50-ft wetlands buffer zone, and enhanced energy efficiency in accordance with the Massachusetts Executive Office of Energy and Environmental Affairs (EEA) 2010 Greenhouse Gas (GHG) Emissions Policy and Protocol. The Project will also implement a stormwater management system that provides stormwater recharge. Primary beneficial public health impacts include the removal of PFAS and 1,4-dioxane from public drinking water supplies, both of which have been linked to negative health impacts. To achieve the project benefits, construction activities have been designed to avoid, minimize and mitigate negative environmental impacts to the extent feasible. Unavoidable negative impacts include tree removal and construction activities within wetland buffer zones. The proposed Project has been sited to reduce impacts to wetland resources to the greatest extent practicable by re-locating infrastructure outside of regulated buffers and restoring previously developed areas with native seed. An erosion and sedimentation control program will be implemented to minimize temporary impacts to wetland resource areas during the construction phase of the Project. A Stormwater Pollution Prevention Plan is included as Attachment E. Proper implementation of the erosion and sedimentation control measures includes: › Minimizing exposed soil areas through sequencing and temporary stabilization; › Placing structures to manage stormwater runoff and erosion; › Use of de-watering filters such as filter bags and straw bale basins; and › Establishing a permanent vegetative cover or other forms of stabilization as soon as practicable. NOI: Straightway and Hyannisport Water Treatment Facilities Improvements Page 10 Non-Structural Practices Non-structural practices to be used during construction include temporary stabilization, temporary seeding, permanent seeding, and dust control. These practices will be initiated as soon as practicable in appropriate areas within the Project Area. Temporary Stabilization Any areas of exposed soil or stockpiles that will remain inactive for more than 14 days will be surrounded by erosion control devices and covered with polyurethane sheeting. Temporary Seeding If conditions allow, a temporary vegetative cover will be established on areas of exposed soils (including stockpiles) that remain unstabilized for a period of more than 60 days. The seeded surfaces will be covered with a layer of straw mulch or bonded fiber matrix. The seed mix shall include a blend of rapid germinating grasses that are indigenous to eastern Massachusetts. Permanent Seeding 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. The mix will be applied at a rate specified by the manufacturer and will be covered with mulch or bonded fiber matrix. The project requests that the Commission waive the mitigation requirements stated in the Town of Barnstable Bylaw Chapter 704-4.B. Given the site layout, it is unfeasible to provide planting mitigation areas three times larger than the hardscape impacts within the 100-foot buffer zone, as shown in Table 3 below. The project qualifies for a waiver in accordance with Chapter 704-6.A(3), as it is undertaken by a government agency that can be demonstrated to provide an overriding public benefit. Proposed plantings are detailed in Table 4 below. Plantings are proposed within the 50' buffer area for restoration of the buffer to the maximum extent practical while meeting project requirements. Table 3. 50’ Buffer Zone Mitigation Calculation Straightway Proposed Hardscape Within 50’ Buffer 0 SF Hyannisport / Simmons Pond Proposed Hardscape Within 50’ Buffer 1,047 SF Straightway Proposed Hardscape Within 50-100’ Buffer 2,136 SF Hyannisport / Simmons Pond Proposed Hardscape Within 50-100’ Buffer 2,385 SF Total Proposed New Hardscape Within Buffer Areas 5,568 SF Area Of Mitigation Required (Multiplied By 3) 16,704 SF Total Proposed Restoration Area Within 50’ Buffer 6,822 SF NOI: Straightway and Hyannisport Water Treatment Facilities Improvements Page 11 Table 4. 50’ Buffer Zone Mitigation Proposed Plantings Type Species Spacing O.C. (ft) Area (SF) Number Total Area (SF) Low Shrub Huckleberry 3 7.1 15 106.0 Low Shrub Late Lowbush Blueberry 3 7.1 15 106.0 Med Shrub Common Elderberry 4 12.6 15 188.5 Med Shrub Rose Bay Rhododendron 10 78.5 15 1178.1 Tall Shrub Mountain Laurel 6 28.3 12 339.3 Tall Shrub Pussy Willow 10 78.5 12 942.5 Tree, Small Flowering Dogwood 15 176.7 5 883.6 Tree, Small Ironwood 20 314.2 5 1570.8 Tree, Tall Black Gum, Sourgum 20 314.2 5 1570.8 Tree, Tall American Sycamore 30 706.9 5 3534.3 Total 6,885.6 Dust Control The erosion and sediment control program includes provisions to minimize the generation of dust during dry and windy conditions. When necessary, larger areas of exposed soil will be wetted to prevent wind borne transport of fine-grained sediment. Enough water shall be applied to wet the upper 0.5 inches of soil. The water will be applied as a fine spray to prevent erosion. A water truck will be kept on the property (or at a nearby location) to facilitate this practice. Structural Practices Structural erosion and sedimentation controls to be used on the Project Area include barriers, catch basin inlet protection, and dewatering filters. Erosion Control Barriers Prior to any ground disturbance, an approved erosion control barrier 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. The barriers will be entrenched into the substrate to prevent underflow. If sediment has accumulated to a depth which 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 in the Project Area or disposed of at a suitable offsite location. Any damaged sections of the barrier will be repaired or replaced immediately upon discovery. Filter Bags and Straw Bale Basins NOI: Straightway and Hyannisport Water Treatment Facilities Improvements Page 12 If necessary, sediment laden water that collects in trenches or excavated areas will be pumped into straw bale basins or filter bags. The basins will consist of a ring of staked straw bales overlain by non-woven geotextile filter fabric and crushed stone. Discharge water will be pumped into the basin and allowed to drain through the fabric onto relatively flat stabilized surfaces. Dewatering filter bags may be used in place of straw bale basins. The bags will be placed on relatively flat terrain, free of brush and stumps, to avoid ruptures and punctures. A maximum of one six-inch discharge hose will be allowed per filter bag. To help prevent punctures, geotextile fabric will be placed beneath the filter bag when used in wooded locations. Unattended filter bags will be encircled with a straw bale and silt fence barrier. All dewatering structures will be placed as far away from wetland resources as possible. Filter bags used during construction will be bundled and removed for proper disposal. Summary The Applicant respectfully requests that the Barnstable Conservation Commission find these measures adequately protective of the interests identified in the WPA and issue an Order of Conditions approving the work described in this NOI, as shown on the accompanying figures.