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HomeMy WebLinkAbout2024-5-8 Piotr Domaszczynski, PhD, PE, Ramboll, Comments on DEIS Draft Scoping Document 1/2 Doc ID / Version May 8, 2024 Ramboll 333 West Washington Street Syracuse, NY 13202 USA T 315-956-6100 F 315-463-7554 https://ramboll.com Ref Confidential Mr. Greg Usry City Manager City Hall 1051 Boston Post Road Rye, NY 10580 Dear Mr. Usry, On April 30, 2024, Ramboll Americas Engineering Solutions Inc. (Ramboll) was commissioned by the City of Rye to conduct a technical review of Section 6, titled “Stormwater Management,” of the Draft Environmental Impact Statement (DEIS) Scoping Document for the proposed redevelopment of the 975 Anderson Hill property. The proposed redevelopment includes the construction of a mixed-use project comprising a new lodge (hotel and conference center, residential units, ballrooms, and other amenities), a separate multifamily residential building, and a wellness center/medical office building, along with associated amenities, landscaping, parking, and other site improvements. This project spans approximately 84 acres of land formerly known as Doral Arrowwood and Doral Greens. The site is adjacent to Blind Brook, a stream with a significant history of flooding, causing substantial damage to properties, businesses, and infrastructure in local communities. Given the considerable public interest in the hydrologic impacts of any development within the Blind Brook watershed, it is imperative that the EIS thoroughly evaluates the project’s impact on stormwater runoff. After reviewing Section 6 of the associated DEIS, we propose the following additional elements for consideration: a) The proposed evaluation of existing conditions (Section 6.2) should provide a detailed breakdown of impervious and pervious areas, associated hydrologic soil groups, slope steepness, and land cover. A hydrologic model should be developed to define peak runoff rates for a 1-year, 2-year, 5-year, 10-year, 25-year, and 100-year (24-hour) storm event. b) Potential impacts (Section 6.3) should include a summary of changes to land cover, particularly any increase in impervious areas or introduction of steep slopes. A "proposed conditions" hydrologic model should be developed to compare peak runoff rates with the rainfall conditions listed in point a. 2/2 Doc ID / Version Confidential c) The stormwater management system description should include all discharge points to existing stormwater system conveyances at or near the project site, as well as any runoff toward Blind Brook. Evaluation of conveyance capacity for any existing elements should be conducted for design storm conditions. d) Stormwater mitigation methods should address any increase in stormwater runoff rates and include water quality measures required by the New York State Department of Environmental Conservation (Construction General Permit) as well as applicable Village of Rye Brook regulations. e) Development within existing FEMA-defined floodplain should be identified and minimized, with standard evaluation of floodplain impacts if such impacts are present. f) Preservation of undisturbed areas, riparian buffers, vegetation, and impervious areas should be maximized. g) Given the significant flooding potential of Blind Brook, the project should consider implementing Best Management Practices (BMPs) that exceed minimum requirements and provide a net benefit to the community. Examples of such practices include rain gardens, stormwater planters, rainwater harvesting, ponds capable of accepting stormwater runoff, constructed wetlands, and infiltration practices, with design implementation following the New York State Stormwater Design Manual. Yours sincerely, Piotr Domaszczynski, PhD, PE Project Manager Ramboll Americas Engineering Solutions, Inc. www.ramboll.com cell: 319-400-9607 piotr.domaszczynski@ramboll.com