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Home My WebLink About20180574 Bethesda Church 4th Engineering Comment 2-27-20 THE Capital District Office C�/� Q�In 547 River Street,Troy, NY 12180 �'-�� P: (518) 273-0055 F: (518) 273-8391 COMPAN I ES www.chazencompanies.com � Engineers Hudson Valley Office (845)454-3980 Environmental Professionals North Country Office (518)812-0513 Land Surveyors Landscape Architects Planners Mr. Michael B. Veitch, Business Manager, Mr. Albert Flick, Senior Engineering Technician City of Saratoga Springs Dept. of Public Works 474 Broadway Saratoga Springs, New York 12866 February 27, 2020 Re: Technical Review of Documents-4th submittal eethesda Parish House 26 Washington Street City of Saratoga Springs,Saratoga County, New York City Project No. 15.020 Chazen Project No. 31504.07 Gentlemen, The Chazen Companies (Chazen) have completed our review of the following materials received: • Site Plans entitled "Bethesda Parish House" consisting of the following 10 sheets, prepared by The LA Group P.C.: o Cover Sheet, last revised February 28, 2017 o S-1 Survey by Thomson Fleming Land Surveyors, P.C., last revised May 19, 2015 o C-1 Site Preparation & Erosion Control Plan, last revised March 7, 2017 o C-2 Layout& Materials Plan, last revised March 7, 2017 o C-3 Grading, Drainage&Utility Plan, last revised March 7, 2017 o C-4 Site Details, last revised March 7, 2017 o C-5 Site Details, last revised March 7, 2017 o C-6 Utility Details, last revised March 7, 2017 o C-7 Stormwater Details, last revised March 7, 2017 o C-8 Stormwater Details, last revised March 7, 2017 • Stormwater Pollution Prevention Plan, prepared by The LA Group, P.C. LLP, last revised August 28, 2015 • Letter response to comments, prepared by The LA Group, P.C, dated September 17, 2015. Following are our observations/comments. The numbers correspond to our previous review letter dated September 2, 2015. Items that have been satisfactorily addressed are not repeated. New comments are presented in bold: Drawin�s 8. Additional drainage piping shown as Alternate 2 along the south and west sides of the building appears to connect to a proposed 6" pipe connecting AD#8 with Catch Basin #1. If the runoff is intended to be directed to the underground sand filter and storage chambers, the SWPPP must be modified to include this. Bethesda Parish House PB#15.020 February 27,2020 Page 2 SWPPP 1. The SWPPP should identify if construction may impact any listed, proposed to be listed, threatened or endangered species, or a critical habitat, or archeological/historic resources. The applicant indicated that the project area is within an area shown on the NYS OPRHP website that might contain archaeologically sensitive resources, and they are coordinating with NYS OPRHP for signoff on the project. This remains an outstanding item and the SWPPP cannot be approved until this documentation is provided. The applicant has indicated that a copy of the OPRHP findings is included in the SWPPP, however an updated SWPPP was not provided. Please include this documentation in the SWPPP. 2. The SWPPP should include calculations for water quality volume and runoff reduction volume, and supporting calculations demonstrating that post-construction stormwater quality practices are designed in conformance with the sizing criteria included in the NYSDECStormwater Management Design Manual. Water Quality Volume (WQv) calculations were provided for only the small portion of the site tributary to the proposed hydrodynamic separator. The SWPPP indicates that roof runoff will not be treated because it will be free of total suspended solids, oil and grease and other pollutants typically found in runoff from roads and parking lots. The Design Manual includes buildings/roofs in the definition of impervious cover, and documentation available on the NYSDEC web site (http://www.dec.nv.�ov/docs/water pdf/techfaq.pdf) discusses why treatment of roof runoff is required (particularly items 4 and 8). The City of Saratoga Springs Stormwater Regulations requires that the SWPPP conform with the requirements of the NYSDEC SPDES General Permit and the NYS Stormwater Management Design Manual (Design Manual). Therefore, the WQv calculations should include all impervious surfaces proposed, including the proposed roof. Please revise the SWPPP accordingly. The SWPPP identifies Subcatchment P1 as an area of the roof that is designed to enter the underground sand filter. The calculations in the SWPPP appear correct, however the drawings appear to show this portion of the roof discharging into the underground chambers via two 6" HDPE pipes without passing through the sand filter. Please clarify. The response received does not address the discrepancy between the SWPPP (showing roof area directed to the sand filter) and the drawings (showing the roof drain connection directly to the storage chambers). Roof area is required to be treated for WQv in accordance with the NYS Stormwater Management Design Manual. Please revise the SWPPP accordingly. 9. Please verify that the 18" storm sewer that is to be installed along Washington Street as part of the Rip Van Dam project (as well as the downstream system) has capacity to accept the increased discharge of stormwater from this project. Please note that the entire site does not currently discharge into the Washington Street storm sewer system. If you would like to meet to discuss this issue, please let us know. Is the applicant in a position to install the 18" storm sewer that is proposed to be installed by the Rip Van Dam contractor if that project is delayed? Bethesda Parish House PB#15.020 February 27,2020 Page 3 The response received indicates if the Rip Van Dam project is delayed then Bethesda will install the 18" line and that Bethesda will enter into a private agreement for cost sharing prior to Chairman signing the mylars. Their response also indicates that $100,000 will be included in a letter of credit to cover the cost of constructing the 18"storm line. It is our understanding that the Rip Van Dam project is delayed, however the City will not require the applicant to install the 18" storm sewer and will instead allow a direct connection to the existing 8" storm sewer in Washington Street until the new 18" storm sewer is installed. The City has acknowledged that the existing storm sewer in Washington Street and Broadway is known to be undersized and can potentially surcharge due to overloading from added flow from the Bethesda site. En�ineer's Report 2. The engineer's report should include calculations demonstrating the reserve capacity of the City sewer system to accept the additional flow from the proposed project. The applicant indicated they are coordinating with the City for available documentation on the sewer system capacity, and that sewer capacity was not raised as a concern during preliminary discussions with the City.This remains an outstanding item. It is our understanding that the project now includes supportive housing and shelter, meals, and recovery from alcohol or substance abuse disorders.The engineer's report should be revised to include the additional water demand and wastewater generation calculations for this use. Traffic and Parkin� 3. No discussion of the existing off-site parking supply is provided. A discussion of current conditions is necessary to support the statement that the additional parking demand does not represent a significant parking impact. We understand Site Plan Approval was granted by the Planning Board. The City should determine if traffic and the additional parking demand should be addressed. In order to expedite and simplify the review of revised materials we would appreciate if the next submission be accompanied by a response letter that describes the revised materials and how our comments were/were not integrated. If you have any comments, questions or need additional information, please do not hesitate to contact this office at 518-273-0055. Sincerely, _ �_. .� { ; , '' i r .�-- , �I ; �. —�--__, � �._. _. . }�' 1 James J. Connors, P.E., Principal Sr. Director, Engineering Services cc: Walter Kubow, PE, File