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Home My WebLink AboutDEC response 7-5028-00106 (002) April 18, 2024 Mark Baxendell Town of Groton Town Board 101 Conger Blvd PO Box 36 Groton, New York 13073 RE: NY Groton I, LLC Solar Project DEC Facility ID#: 7-5028-00106 Town of Groton, Tompkins County SEQR Lead Agency Coordination Response Letter Dear Mr. Baxendell: The New York State Department of Environmental Conservation (DEC) has reviewed the Town of Groton Town Board’s Notice of Intent to serve as SEQR Lead Agency, submitted on their behalf by Delaware River Solar, for the above referenced project. According to the provided materials, the project consists of the installation of a 5.0 MW AC ground mounted solar facility, which includes the construction of a gravel access road and installation of an eight (8) foot high deer fence, and electric utility lines in the Town of Groton, Tompkins County. Based upon the review of your inquiry, DEC has the following comments: PROTECTION OF WATERS There are no protected waterbodies identified within the project area. Though a permit is not required, please note, however, the project sponsor is still responsible for ensuring that work shall not pollute any stream or waterbody. Care shall be taken to stabilize any disturbed areas promptly after construction, and all necessary precautions shall be taken to prevent contamination of the stream by silt, sediment, fuels, solvents, lubricants, or any other pollutant associated with the project. FRESHWATER WETLANDS The project site is not located near or within the regulated area of a NYS Freshwater Wetland, therefore, a Freshwater Wetlands Permit is not required. Please note, however, the project sponsor should contact town officials and the United States Army Corps of Engineers (USACE) Auburn Field Office, at (315) 255- 8090 for any permitting they might require. Please also be aware that pursuant to the Clean Water Act, a Section 401 Water Quality Certification may be required from the Department if a Section 404 Permit is required by the USACE for the placement of fill within waters of the United States. STATE-LISTED SPECIES No records of sensitive resources were identified by this review. The absence of data does not necessarily mean that rare or state-listed species, natural communities or other significant habitats do not exist on or adjacent to the proposed site. Rather, our files currently do not contain information which indicates their RE: NY Groton I, LLC Date: 4/18/2024 DEC Facility ID#: 7-5028-00106 Town of Groton, Tompkins County SEQR Lead Agency Coordination Response Letter Page 2 of 2 presence. For most sites, comprehensive field surveys have not been conducted. We cannot provide a definitive statement on the presence or absence of all rare or state-listed species or significant natural communities. Depending on the nature of the project and the conditions at the project site, further information from on-site surveys or other sources may be required to fully assess impacts on biological resources. STATE POLLUTANT DISCHARGE ELIMINATION SYSTEM (SPDES) Soil disturbances of one or more acres of land from construction activities must obtain permit coverage under the NYSDEC SPDES General Permit for Stormwater Discharges from Construction Activities (GP - 0-20-001) by submitting a Notice of Intent and developing & implementing a Stormwater Pollution Prevention Plan. For further information please consult with Brian Hall in DEC’s Division of Water at (315) 479-3430 or review the NYSDEC Stormwater webpage. Additionally, please see the attached solar panel stormwater permitting guidance document. If the project does not meet ALL criteria for Scenario 1, including alignment of solar panels along the contour, the SWPPP must address post-construction stormwater practices designed in accordance with the sizing criteria identified in the New York State Stormwater Management Design Manual. In addition to transmitting the above comments, this letter also serves to confirm that we have no objection to your board/agency assuming lead agency status for this project. Additionally, by copy of this letter, the Department is notifying the project sponsor of any potential permitting required for this project. Please contact this office if you have questions regarding the above information. Thank you. Sincerely, Melanie Kukko Environmental Analyst Division of Environmental Permits, Region 7 Telephone No. (315) 426-7482 cc: USACE J. Stercho, R7 DEP B. Hall, R7 DOW M. Messenger, Delaware River Solar M E M O R A N D U M TO: Regional Water Engineers FROM: Robert Wither, Chief, South Permit Section SUBJECT: Solar Panel Construction Stormwater Permitting/SWPPP Guidance DATE: April 5, 2018 Issue The Department is seeing an increase in the number of solar panel construction projects across New York State. This has resulted in an increase in the number of questions on Construction General Permit (CGP) and Stormwater Pollution Prevention Plan (SWPPP) requirements from design professionals because the current CGP (GP- 0-15-002) does not include a specific reference to the SWPPP requirements for solar panel projects in Tables 1 and 2 of Appendix B. To address this issue, the Division of Water (DOW) has developed the following guidance on CGP/SWPPP requirements for the different types of solar panel projects. Scenario 1 The DOW considers solar panel projects designed and constructed in accordance with the following criteria to be a “Land clearing and grading for the purposes of creating vegetated open space (i.e. recreational parks, lawns, meadows, fields)” type project as listed in Table 1, Appendix B of the CGP. Therefore, the SWPPP for this type of project will typically just need to address erosion and sediment controls. 1. Solar panels are constructed on post or rack systems and elevated off the ground surface, 2. The panels are spaced apart so that rain water can flow off the down gradient side of the panel and continue as sheet flow across the ground surface*, 3. For solar panels constructed on slopes, the individual rows of solar panels are generally installed along the contour so rain water sheet flows down slope*, 4. The ground surface below the panels consist of a well-established vegetative cover (see “Final Stabilization” definition in Appendix A of the CGP), 5. The project does not include the construction of any traditional impervious areas (i.e. buildings, substation pads, gravel access roads or parking areas, etc.), 6. Construction of the solar panels will not alter the hydrology from pre -to post development conditions (see Appendix A of the CGP, for definition of “Alter the hydrology…”). Note: The design professional shall perform the necessary site assessment/hydrology analysis to make this determination. *Refer to Maryland’s “Stormwater Design Guidance- Solar Panel Installations” attached for guidance on panel installation. **See notes below for additional criteria. Scenario 2 If the design and construction of the solar panels meets all the criteria above, except for item 6, the project will fall under the “All other construction activities that include the construction or reconstruction of impervious area or alter the hydrology from pre-to post development conditions, and are not listed in Table 1” project type as listed in Table 2, Appendix B of the CGP. Therefore, the SWPPP for this type of project must address post-construction stormwater practices designed in accordance with the sizing criteria in Chapter 4 of the NYS Stormwater Management Design Manual, dated January 2015 (Note: Chapter 10 for projects in NYC EOH Watershed). The Water Quality Volume (WQv)/Runoff Reduction Volume (RRv) sizing criteria can be addressed by designing and constructing the solar panels in accordance with the criteria in items 1 – 4 above, however, the quantity control sizing criteria (Cpv, Qp and Qf) from Chapter 4 (or 10) of the Design Manual must still be addressed, unless one of the waiver criteria from Chapter 4 can be applied. **See notes below for additional criteria. ** Notes - Item 1: For solar panel projects where the panels are mounted directly to the ground (i.e. no space below panel to allow for infiltration of runoff), the SWPPP must address post-construction stormwater management controls designed in accordance with the sizing criteria in Chapter 4 of the NYS Stormwater Management Design Manual, dated January 2015 (Note: Chapter 10 for projects in NYC EOH Watershed). - Item 5: For solar panel projects that include the construction of traditional impervious areas (i.e. buildings, substation pads, gravel access roads or parking areas, etc.), the SWPPP must address post-construction stormwater management controls for those areas of the project. This applies to both Scenario 1 and 2 above. cc: Carol Lamb-Lafay, BWP Dave Gasper, BWP Page 1 Maryland Department of the Environment Stormwater Design Guidance – Solar Panel Installations Revisions to Maryland’s stormwater management regulations in 2010 require that environmental site design (ESD) be used to the maximum extent practicable (MEP) to mimic natural hydrology, reduce runoff to reflect forested wooded conditions, and minimize the impact of land development on water resources. This applies to any residential, commercial, industrial, or institutional development where more than 5,000 square feet of land area is disturbed. Consequently, stormwater management must be addressed even when permeable features like solar panel installations exceed 5,000 square feet of land disturbance. Depending on local soil conditions and proposed imperviousness, the amount of rainfall that stormwater requirements are based on varies from 1.0 to 2.6 inches. However, addressing stormwater management does not mean that structural or micro-scale practices must be constructed to capture and treat large volumes of runoff. Using nonstructural techniques like disconnecting impervious cover reduces runoff by promoting overland filtering and infiltration. Commonly used with smaller or narrower impervious areas like driveways or open roads, the Disconnection of Non-Rooftop Runoff technique (see pp. 5.61 to 5.65 of the 2000 Maryland Stormwater Design Manual1) is a low cost alternative for treating runoff in situations like rows of solar panels. When non-rooftop disconnection is used to treat runoff, the following factors should be considered: • The vegetated area receiving runoff must be equal to or greater in length than the disconnected surface (e.g., width of the row of solar panels) • Runoff must sheet flow onto and across vegetated areas to maintain the disconnection • Disconnections should be located on gradual slopes (≤ 5%) to maintain sheetflow. Level spreaders, terraces, or berms may be used to maintain sheetflow conditions if the average slope is steeper than 5%. However, installations on slopes greater than 10% will require an engineered plan that ensures adequate treatment and the safe and non-erosive conveyance of runoff to the property line or downstream stormwater management practice. • Disconnecting impervious surfaces works best in undisturbed soils. To minimize disturbance and compaction, construction vehicles and equipment should avoid areas used for disconnection during installation of the solar panels. • Groundcover vegetation must be maintained in good condition in those areas receiving disconnected runoff. Typically this maintenance is no different than other lawn or landscaped areas. However, areas receiving runoff should be protected (e.g., planting shrubs or trees along the perimeter) from future compaction. Depending on the layout and number of panels installed, the disconnection of non-rooftop runoff technique may address some or all of the stormwater management requirements for an individual project. Where the imperviousness is high or there is other infrastructure (e.g., access roads, transformers), additional runoff may need to be treated. In these situations, other ESD techniques or micro-scale practices may be needed to provide stormwater management for these features. Example 1 – Using Non-Rooftop Disconnection Where the Average Slope ≤ 5% Several rows of solar panels will be installed in an existing meadow. The soils within the meadow are hydrologic soil group (HSG) B and the average slope does not exceed 5%. Each row of panels is 10 feet wide and the distance between rows is 20 feet. The rows of solar panels will be installed according to Figure 1 below. In this scenario, the disconnection length is the same as the distance between rows (20 feet) and is greater than the width of each row (10 feet). Therefore, each row of panels is adequately disconnected and the runoff from 1.0 inch of rainfall is treated. Figure 1. Typical Installation - Slope ≤ 5% Example 2 – Using Non-Rooftop Disconnection Where the Average Slope ≥ 5% but ≤ 10% Several rows of solar panels will be installed in an existing meadow. The soils within the meadow are hydrologic soil group (HSG) B and the average slope is greater than 5% but less than 10%. Each row of panels is 10 feet wide and the distance between rows is 20 feet. The rows of solar panels will be installed as shown in Figure 2 below. The disconnection length is the same as the distance between rows (20 feet) and is greater than the width of each row (10 feet). However, in this example, a level spreader (typically 1 to 2-foot wide and 1 foot deep) has been located at the drip edge of each row of panels to dissipate energy and maintain sheetflow. Discussion To meet State and local stormwater management requirements, ESD must be used to the MEP to reduce runoff to reflect forested conditions. While all reasonable options for implementing ESD must be investigated, minimally, the runoff from 1 inch of rainfall must be treated. In each of the examples above, there may be additional opportunities to implement ESD techniques or practices and reduce runoff that should be explored. However, simply disconnecting the runoff from the solar panel arrays captures and treats the runoff from 1.0 inch of rainfall. Where imperviousness is low and soil conditions less optimal (e.g., HSG C or D), this may be sufficient to completely address stormwater management requirements. In more dense applications or in sandy soils, additional stormwater management may be required. Page 2 Conclusion The primary purpose of Maryland’s stormwater management program is to mimic natural hydrologic runoff characteristics and minimize the impact of land development on water resources. Any land development project that exceeds 5,000 square feet of disturbance, including solar panel projects, must address stormwater management. However, for solar panels, stormwater management may be provided in a cost-effective manner by disconnecting each row of panels and directing runoff over the vegetated areas between the individual rows. Resources 1 2000 Maryland Stormwater Design Manual, Volumes I and II, MDE, October 2000 (http://www.mde.state.md.us/programs/Water/StormwaterManagementProgram/MarylandStormwaterDesignMa nual/Pages/Programs/WaterPrograms/SedimentandStormwater/stormwater_design/index.aspx) Figure 2. Typical Installation – Slope ≥ 5% but ≤ 10% Page 3