Documents › Planning Board, 2026-07-28

site plan 17 pages

Preliminary water engineering report by Cronin Engineering, dated December 23, 2025, for the proposed 49-unit rental building (25 one-bedroom and 24 two-bedroom units) with 79 parking spaces at 425 S. Riverside Avenue. Design maximum daily water demand is 8,030 gallons per day, with anticipated actual use of 4,828 gpd, and fire sprinkler demand of 750 gpm for 60 minutes. Hydrant tests from March 27, 2025 show the existing 6-inch main in South Riverside Avenue can supply domestic needs but delivers less than 500 gpm at 20 psi for fire flow, so the report discusses two alternatives: connecting the South Riverside Avenue and Wayne Street mains or an onsite water storage and pump system.

Also attached to this agenda item: 425 S Riverside Ave-Croton-Site Development Plans Architectural Plans 425 S Riverside Signed 7.17.26 Coastal Assessment Form Fiscal Report 425 SRA Full Environmental Assessment Form Gateway Overlay District Compliance Memo Landscape Plan 425 SRA NPV Memo 425 S Riverside Ave 07-24-2026 Neighbor Letters x 2 425 SRA Neighbor Letters 425 SRA PB Application PB Cover Letter 7.13.26

December 23, 2025 PRELIMINARY WATER ENGINEERING REPORT 425 S. RIVERSIDE AVENUE CROTON-ON-HUDSON WESTCHESTER COUNTY, NEW YORK DATE: DECEMBER 23, 2025 Prepared By Cronin Engineering, P.E., P.C. 39 Arlo Lane Cortlandt Manor, New ork 10567 Water Engineering Report – 425 South Riverside Avenue Cronin Engineering, P.E., P.C. 1.0 INTRODUCTION 1.1 Project Description The project consists of a proposed 49-unit rental development consisting of 25 one-bedroom and 24 two-bedroom units in a to be constructed 3-story building with requisite parking and amenities (the “Development”) to be located on lands fronting on South Riverside Avenue on Tax Map Parcel 79.13-2-91 owned by Carmel Riverside LLC. The site is currently improved with a 12,600 square foot, 1-story brick and block building and associated asphalt parking lot, which is proposed to be removed for the Development. The proposed building will be served by 79 parking spaces. 56 spaces located in a below grade parking level and 23 in an outdoor parking area in front of the building, including five (5) Level 2 EV charging stations. Amenities within the building will include a community room, a fitness center, a co-working lounge, E-bike & bike storage rooms and a roof-top deck providing expansive scenic views overlooking Croton Point Bay and the Hudson River. Sustainable building design features will likely include full electrification, solar readiness, high efficiency HVAC equipment (cold climate air source heat pumps) and appliances (Energy Star Multifamily New Construction Program) and low-flow water fixtures. In total the property consists of 83,891 square feet (1.9  acres) and is located in the C-2 (Commercial) Zoning District and the HSRG (Harmon/South Riverside Gateway) Gateway Overlay Zoning District, the Village of Corton-on-Hudson Water District and the Ossining Sanitary Sewer District. 1.2 Existing Site Conditions The subject project is located on South Riverside Avenue across from the ShopRite Plaza in the Village of Croton-On-Hudson. As previously stated, the site currently exists as a commercial development with one 12,600 sf brick and block building and associated asphalt parking lot and other appurtenances. 1.3 Proposed Site Conditions It is proposed to construct a 24,200 sf  (footprint area) affordable condominium development with associated parking and various site appurtenances. The new three-story building will contain 49 units. There will be 25 one-bedroom apartments and 24 two-bedroom apartments. Amenity spaces will also be constructed which will be used by the residents of the building. As part of the proposed development, there will be a new domestic water and fire service connection to the building. The new service lines will exit the building on the west side and will tie into the existing water main on South Riverside Avenue. See Appendix A for Water Main & Service mapping. 2.0 PROJECT DESIGN FLOWS The project domestic maximum daily water demand used for design is anticipated to be the same as the maximum daily wastewater demand. As such the design maximum daily water flows for the proposed project, are based on the hydraulic loading rates given in the New York State Department of Environmental Conservation (NYSDEC) publication Design Standards for Intermediate Sized Wastewater Treatment Works – 2014 (DEC 2014). The design maximum daily water demand is a conservative design flow on which the water infrastructure will be designed. This value does not represent the average daily demand, which is expected to be less, or the peak demand. The design flow rates for the residential units are based on the number of bedrooms per the tables below. The following table calculates the hydraulic loading rates, and the design flow rates (gallons per day or gpd) for the proposed project. Cronin Engineering, P.E., P.C. Water Engineering Report – 425 South Riverside Avenue Proposed Use # of Units Hydraulic Loading Rate Design Maximum Daily Flow (gpd) One Bedroom Units 25 Units 110 gpd/bedroom 2,750 Two Bedroom Units 24 Units 110 gpd/bedroom 5,280 Total 8,030 The anticipated design average daily flows for the project are expected to be significantly less than the design maximum daily flow rate. The design maximum daily flows represent conservative flows to ensure that the proposed sewer works are designed with an ample factor of safety. The anticipated actual flows are based on anticipated occupancy rates and measured data for water use. Statistical data (obtained from Rutgers University, Center for Urban Policy Research, Residential Demographic Multipliers, June 2006) for the average number of occupants in rental units (based on number of bedrooms) was used to calculate the expected number of residents anticipated for the project as shown in the table below. Data from the American Water Works Association (“AWWA”) Water Conservation Division Subcommittee Report, Water Conservation Measurement Metrics Guidance Report, dated January 2010 shows that the average in home water use is 69.3 gpd per person. This number is reduced to 43.5 gpd per person when water saving fixtures are used, which is the case for this project. The following table below will be used to calculate flow to the existing sewer main. The 45 gpd per person was used to calculate the proposed anticipated average daily design as water saving fixtures will be used. See the table below for the calculation of the design average daily flow rates in the existing and proposed conditions. Table 2.3: 425 S. Riverside Ave - Proposed Design Average Daily Flow Rate Proposed Use Occupancy Rate Total Anticipated Residents Water Use Per Resident (gpd) Water Use (gpd) 25 – One Bedroom Units 1.206 people/unit 43.5 1,305 24 – Two Bedroom Units 1.689 people/unit 43.5 3,523 Total Anticipated Water Use (gpd) 4,828 As demonstrated above, through the use of water saving fixtures as required by current building code, a design maximum flow of 8,030 gpd is proposed for the project, with the actual anticipated flows being 4,828 gpd. The peak hourly flow is calculated using a peaking factor that is based on the population of the subject project. A peaking factor of four (4) will be used for the project based on Figure 1 from Recommended Standards for Wastewater Facilities. Peak Hourly Domestic Flow 8,030 gpd ÷ (24 hr/day) ÷ (60 min/hr) = 5.6 gallons per minute (gpm) Peak Hourly Flow = 5.6 gpm x 4 = 22 gpm Although the anticipated flows (average daily design flow) for the project is significantly lower than the design maximum daily flows, the Peak Hourly Flow based on the design maximum daily flows are used for the design of the system. This provides a factor of safety in the proposed design. The new building is required to have fire sprinklers. The requirements for fire sprinkler systems were preliminarily established for the project based on review by the Fire System Design engineer. The fire sprinkler demand for the building is dictated by the required flow for the project and was provided 750 gpm for 60 minutes. The final fire sprinkler system will meet NFPA requirements and be designed by the Fire System Design engineer during the building permit process. Cronin Engineering, P.E., P.C. Water Engineering Report – 425 South Riverside Avenue 3.0 PROPOSED CONNECTION TO VILLAGE OF CROTON-ON-HUDSON SYSTEM 3.1 System Characteristics Based on mapping provided of the existing system there is an existing 6-inch main in South Riverside Avenue that services the existing structure on the subject property. There is also an existing 10-inch main in Wayne Street. See Appendix A for Water Main mapping and Appendix B for Hydrant Flow Test results. 3.2 Proposed Water Service Connection and Hydrant The existing water main that the project proposes to connect to is the 6-inch in South Riverside Avenue. As previously discussed, two separate service lines, domestic and fire, are proposed. Based on the available mapping provided in Appendix A the existing watermain is a 6-inch diameter pipe in South Riverside Avenue. All water service piping 4-inch and greater will be Class 52 DIP. Restrained joint connections will be provided at all pipe bends through the use of Mega-lug fittings or approved equal. In addition, thrust blocks will be provided at all bends. Upon completion of the water service installation pressure testing, disinfection, and flushing will be performed in accordance with AWWA standards. In addition to the water service connections proposed, an existing fire hydrant will need to be relocated to accommodate the proposed retaining wall along South Riverside Avenue. The hydrant will need to be moved closer to the road and will be ultimately located between the proposed sidewalk and retaining wall. Recommended Standards for Water Works (“RSWW”) recommends that the normal working pressure not be below 35 psi, and both the RSWW and the American Water Works Association (“AWWA”) M 31 recommend that a minimum of 20 psi be maintained at all points in the water distribution system during fire flows. Hydrant flow tests were completed on March 27, 2025. Two (2) hydrant flow tests were performed including Hydrant H-371 on Young Avenue and Hydrant H-30 on South Riverside Avenue. See Appendix B for additional information regarding hydrant flow testing. The results are summarized in the following table. Flow (gpm) Static Pressure (psi) Residual Pressure (psi) Young Avenue (Hydrant H-371) South Riverside Avenue (Hydrant H-30) Based on this testing the existing 6-inch water main in South Riverside Avenue can supply the domestic needs for the project. However, for fire flow, the 6-inch water main in South Riverside Avenue provides less than 500 gal/min at 20 psi thus not meeting the project fire flow demand. Improvements would be required to provide the 750 gpm sprinkler demand. Two (2) alternatives are discussed below including: Cronin Engineering, P.E., P.C. Water Engineering Report – 425 South Riverside Avenue r r 1. Improvements to the distribution system via a connection between the existing South Riverside Avenue Water Main and the Wayne Street Water Main for the Croton Point Avenue Project (see calculations in Section 3.4 below). 2. Onsite water storage and pump system (see discussion in Section 3.5 below). 3.3 Calculation for Residual Pressure at Service Connection for Peak Domestic Flow The following calculations determine the residual pressure at the service connection to ensure that the minimum pressure of 35 psi is met at the highest service connection as required by RSWW. The calculations assume no distribution system improvements (i.e. Croton Point Ave Project Wayne Street Extension or improvements to be determined on South Riverside Avenue). The residual pressure will be calculated for peak domestic demand of 103 gpm as calculated in section 2.0: 1. Calculate Static Pressure at First Floor Elevation (“FFE”) Static Pressure at Hydrant (South Riverside Avenue) = 138 psi Elevation at Hydrant (South Riverside Avenue) = 45 ft Elevation of Proposed Service Connection = 42 ft Difference in Elevation of FFE & Hydrant (57.5 ft – 45 ft) = +12.5 ft Equivalent pressure Associated with Change in Elev. (12.5 ft / 2.31psi) = -5.4 psi Static Pressure at FFE (138 psi – 5.4 psi) = 132.6 psi 2. Calculate Head Loss in System to Residual Pressure Hydrant at Peak Domestic Flow The equation below is taken from AWWA M17. The equation is used to calculate flow available at different pressures or differences in the residual pressure that would result from different flow rates. Here the equation is used to calculate the residual pressure (at the observation hydrant) for the domestic design flow of the building, using the pressures and flow rates measured during the flow test. The proposed domestic water service lines will be sized for a flow of 103 gpm. Domestic Flow Calculation: QR=QF* h 0.54/ hf0.54 Where: QR = peak flow (103 gpm) QF = flow from hydrant during test (400 gpm) hr = the difference in pressure between the static pressure measured at the observation hydrant and the residual pressure at the total combined flow hf = the difference between the static pressure and residual pressure measured at the observation hydrant during the flow test, (98 psi) 103 gpm = 400 gpm * h 0.54/ 98 psi 0.54 hr = 2 psi 3. Calculate Head Loss at Peak Domestic Flow from Residual Hydrant to Building Total Head Loss Due to Friction (See Spreadsheets in Appendix C) = 4 psi Cronin Engineering, P.E., P.C. Water Engineering Report – 425 South Riverside Avenue r r Domestic Flow Calculation: As noted above the static pressure at the FFE is 132 psi. A head loss of 2 psi was calculated in the system at peak domestic flow to the residual hydrant. An additional 4 psi of head loss was calculated in the existing water main from the residual hydrant to the proposed service line and in the proposed service line to the building. This results in a calculated pressure at FFE of: 132 psi – 2 psi -4 psi = 126 psi As noted above the 126 psi pressure under peak hourly flow conditions exceeds the RSWW requirement of 35 psi for peak hourly domestic flow conditions. The existing system can supply the peak hourly domestic flow without distribution system improvements. As the pressure exceeds 100 psi, a pressure reduction valve should be provided on the domestic plumbing entering the building. 3.4 Calculation for Residual Pressure at Service Connection for Combined Peak Domestic Flow Plus Fire Flow (with Wayne Street Connection) It is understood the Village installed a 10-inch water line in Wayne Street with a stub to South Riverside Avenue to allow the extension of the 10-inch line in Wayne Street to South Riverside Avenue. The following flow and pressure calculations assume that connection is made. The equation below is taken from AWWA M17. The equation is used to calculate flow available at different pressures or differences in the residual pressure that would result from different flow rates. Here the equation is used to calculate the residual pressure (at the observation hydrant) for the domestic design flow of the building, using the pressures and flow rates measured during the flow test. The proposed domestic water service lines will be sized for a flow of 103 gpm. The fire service line will be sized for a flow of 750 gpm. Head Loss in System at Fire Flow Calculation: QR=QF* h 0.54/ hf0.54 Where: QR = peak flow (853 gpm) QF = flow from hydrant during test (400 gpm) hr = the difference in pressure between the static pressure measured at the observation hydrant and the residual pressure at the total combined flow hf = the difference between the static pressure and residual pressure measured at the observation hydrant during the flow test, (30 psi) 853 gpm = 400 gpm * h 0.54/ 30 psi 0.54 hr = 54 psi Fire Flow Calculation: As shown in Appendix C, a head loss of 7-ft (3 psi) is calculated in the fire service line, 52 ft (22 psi) in the existing 6-inch diameter water main and 4-ft (2 psi) in the existing and proposed 10-inch diameter water main. The static pressure of 144 psi and system head loss of 44 psi to the Wayne Street Hydrant are calculated above. This results in a calculated pressure at building FFE of: 144 psi – 3 psi- 22 psi- 2 psi -54 psi = 63 psi As noted above the 63 psi pressure under combined domestic and fire flow conditions exceeds the RSWW requirement for 20 psi throughout the system. The project MEP engineer will complete design of the fire sprinkler system as part of the building permit process. Cronin Engineering, P.E., P.C. Water Engineering Report – 425 South Riverside Avenue 3.5 Water Storage Tank Alternate for Fire Protection As noted above, with an extension of the 10-inch watermain from Wayne Street to South Riverside Avenue, the existing system can supply the required water flow for the fire sprinkler system. While this connection has long been envisioned and desired by the Village the Wayne Street extension requires an easement from a private property owner. Should the easement not be able to be secured, and the Wayne Street extension cannot be completed, an onsite water storage tank and pump system would be used to supplement the available flows from the existing 6-inch watermain in South Riverside Avenue to meet the fire sprinkler requirements. The MEP engineer has determined that a 60-minute duration is required for the 750 gpm sprinkler flow. For this flow rate and duration, a water use of 45,000 gallons is calculated. This water volume would be provided by a combination of the available flows from the existing system, the ability to supply the proposed hydrant, and supplemental onsite storage. Through the site plan process the applicant will work with the Village to determine the required size of the supplemental storage tank. The tank would be buried below grade in the parking garage. Pump(s) would be provided to deliver the required supplemental flow from the storage tank to the sprinkler system. The pump(s) would be in the building mechanical room. A back-up generator will be provided to power the pump(s) in case of utility power failure. All water tanks would be buried below grade. APPENDIX A Croton-On-Hudson Water Main Mapping APPENDIX B Hydrant Flow Test Data APPENDIX C Head Loss Calculation Worksheets Water Engineering Report – 425 South Riverside Avenue APPENDIX A Croton-on-Hudson Water Main Mapping Static / Residual Hydrant Test 2 & Flow Hydrant Test 3 Hydrant Test 1 Static / Residual Flow Hydrant Test 1 Hydrant Test 3 Static / Residual Flow Hydrant Test 2 Water Engineering Report – 425 S. Riverside Avenue APPENDIX B Hydrant Flow Test Data Water Engineering Report – 425 S. Riverside Avenue APPENDIX C Head Loss Calculation Worksheets Cronin Engineering, P.E., P.C. 39 Arlo Lane Cortlandt Manor, New York 10567 (PH) (914) 736-3664 EMAIL: JIM@CRONINENGINEERING.NET Owner Carmel Riverside LLC Address 425 S. Riverside Avenue Town, State, Zip Code Croton-on-Hudson, New York Type of Occupancy Residential Condo Building - Domestic Service Fixture Occupancy Type Load in Fixture Units No. of Fixtures Total Fixture Unit Load Water Closet Public Flush Valve x = Water Closet Public Flush Tank x = Urinal Public 1" Flush Valve x = Urinal Public 3/4" Flush Valve x = Urinal Public Flush Tank x = Lavatory Public Faucet x = Mop Sink Public Faucet x = Shower Head Public Mixing Valve x = Drinking Fountain Public Faucet x = Service Sink Office, etc. Faucet x = Ice Machine Hotel, Restaurant Faucet x = Kitchen Sink Hotel, Restaurant Faucet x = Dishwasher Hotel, Restaurant Faucet x = Laundry Traps (20 lb) Hotel Faucet x = Laundry Traps (30 lb) Hotel Faucet x = Laundry Traps (60 lb) Hotel Faucet x = Water Closet Private Flush Valve x = Water Closet Private Flush Tank x = Lavatory Private Faucet x = Bathtub Private Faucet x = Shower Head Private Mixing Valve x = Bathroom Group Private Flush Valve for closet x = Bathroom Group Private Flush Tank for closet x = Separate Shower Private Mixing Valve x = Kitchen Sink Public Faucet x = Utility Sink Private Faucet x = Hose Connection Public Faucet x = Dishwasher Private Faucet x = Combined Fixture Load - Total F.U. Peak Demand (gpm) gpm = gpm Add Irrigation - Spray System x 1.0 = gpm Add Irrigation - Rotary System x 0.04 = gpm Add Irrigation - Hose Bibs x 10.00 = gpm Additional Fixed Load (If Applicable) = gpm TOTAL PEAK DEMAND gpm DEMAND LOAD OF FIXTURES Peak Demand (gpm) x Factor of 0.5 Note: For fixtures not listed loads should be assumed by comparing the fixture to one listed using water in similar quantities and at similar rates. The given loads are for total demand. For fixtures with both hot and cold water suplies, the loads for separate demands may be taken as three fourths of the loads listed. Owner Carmel Riverside LLC Address 425 S. Riverside Avenue Town, State, Zip Code Croton-on-Hudson, New York Type of Occupancy Residential Condo Building - Domestic Service PIPE DIAMETER 4 in PIPE C FACTOR ESTIMATED FLOW 112 gpm PIPE LENGTH 90 ft (Incl. Misc. Fittings/Valves) HAZEN WILLIAMS FORMULA VELOCITY 2.85 fps FLOW 0.25 cfs AREA 0.09 ft^2 HYDRAULIC RAD. 0.08 ft HEAD LOSS AT PEAK DEMAND 0.5 psi HEAD LOSS THROUGH METERS 2 psi Water Meter HEAD LOSS THROUGH FILTERS 0 psi N/A HEAD LOSS THROUGH BACKFLOW PREVENTER 12 psi Watts LF009 RPZ TOTAL ANTICIPATED HEAD LOSS AT PEAK DEMAND 14.5 psi Typical Max. System Static Pressure 75 psi Typical Min. System Static Pressure 75 psi Elevation of Backflow Preventor in Building 105 ft. Elevation at Water Connection 100 ft. Total Elevation Change 5 ft. HEAD LOSS DUE TO ELEVATION 2.2 psi Anticipated Max. Static Pressure at Backflow Preventor 72.8 psi Anticipated Min. Static Pressure at Backflow Preventor 72.8 psi ANTICIPATED MAX. PRESSURE AT BACKFLOW PREVENTOR DURING PEAK DEMAND 58.3 psi ANTICIPATED MIN. PRESSURE AT BACKFLOW PREVENTOR DURING PEAK DEMAND 58.3 psi HEAD LOSS DATA 12/23/2025 Water Report-Water Service-Sizing-20251209 Cronin Engineering, P.E., P.C. 39 Arlo Lane Cortlandt Manor, New York 10567 (PH) (914) 736-3664 EMAIL: CIVIL@CRONINENGINEERING.NET Owner Carmel Riverside LLC Address 425 S. Riverside Avenue Town, State, Zip Code Croton-on-Hudson, New York Type of Occupancy Residential Cooperative Building - Fire Service Fixture Occupancy Type Load in Fixture Units No. of Fixtures Total Fixture Unit Load Water Closet Public Flush Valve x = Water Closet Public Flush Tank x = Urinal Public 1" Flush Valve x = Urinal Public 3/4" Flush Valve x = Urinal Public Flush Tank x = Lavatory Public Faucet x = Mop Sink Public Faucet x = Shower Head Public Mixing Valve x = Drinking Fountain Public Faucet x = Service Sink Office, etc. Faucet x = Ice Machine Hotel, Restaurant Faucet x = Kitchen Sink Hotel, Restaurant Faucet x = Dishwasher Hotel, Restaurant Faucet x = Laundry Traps (20 lb) Hotel Faucet x = Laundry Traps (30 lb) Hotel Faucet x = Laundry Traps (60 lb) Hotel Faucet x = Water Closet Private Flush Valve x = Water Closet Private Flush Tank x = Lavatory Private Faucet x = Bathtub Private Faucet x = Shower Head Private Mixing Valve x = Bathroom Group Private Flush Valve for closet x = Bathroom Group Private Flush Tank for closet x = Separate Shower Private Mixing Valve x = Kitchen Sink Public Faucet x = Utility Sink Private Faucet x = Hose Connection Public Faucet x = Dishwasher Private Faucet x = Combined Fixture Load - Total F.U. FIRE FLOW Peak Demand (gpm) gpm = gpm Additional Fixed Load (If Applicable) = gpm TOTAL PEAK DEMAND gpm DEMAND LOAD OF FIXTURES Peak Demand (gpm) x Factor of 1.00 Note: For fixtures not listed loads should be assumed by comparing the fixture to one listed using water in similar quantities and at similar rates. The given loads are for total demand. For fixtures with both hot and cold water suplies, the loads for separate demands may be taken as three fourths of the loads listed. Owner Carmel Riverside LLC Address 425 S. Riverside Avenue Town, State, Zip Code Croton-on-Hudson, New York Type of Occupancy Residential Condo Building - Domestic Service PIPE DIAMETER 6 in PIPE C FACTOR ESTIMATED FLOW 750 gpm PIPE LENGTH 90 ft (Incl. Misc. Fittings/Valves) HAZEN WILLIAMS FORMULA VELOCITY 8.51 fps FLOW 1.67 cfs AREA 0.20 ft^2 HYDRAULIC RAD. 0.13 ft HEAD LOSS AT PEAK DEMAND 2.3 psi HEAD LOSS THROUGH METERS 0 psi N/A HEAD LOSS THROUGH FILTERS 0 psi N/A HEAD LOSS THROUGH BACKFLOW PREVENTER 15 psi DCDA TOTAL ANTICIPATED HEAD LOSS AT PEAK DEMAND 17.3 psi Typical Max. System Static Pressure 135 psi Typical Min. System Static Pressure 135 psi Elevation of Backflow Preventor in Building 105 ft. Elevation at Water Connection 100 ft. Total Elevation Change 5 ft. HEAD LOSS DUE TO ELEVATION 2.2 psi Anticipated Max. Static Pressure at Backflow Preventor 132.8 psi Anticipated Min. Static Pressure at Backflow Preventor 132.8 psi ANTICIPATED MAX. PRESSURE AT BACKFLOW PREVENTOR DURING PEAK DEMAND 115.5 psi ANTICIPATED MIN. PRESSURE AT BACKFLOW PREVENTOR DURING PEAK DEMAND 115.5 psi HEAD LOSS DATA 12/23/2025 Water Report-Water Service-Sizing-20251209