Located in the Town of Rotterdam, Carman Road carries NY Route 146 and serves as a significant business corridor to the community. Existing development along the corridor is largely commercial and multi-unit residential development, with single-family homes interspersed. Existing on-site subsurface wastewater systems serve all parcels along Carman Road. Issues within the existing system have been reported, with potential negative impacts on the local groundwater resource.
And this is not your average groundwater resource. The project site lies above the Schenectady-Niskayuna Sole Source Aquifer – a main, unconsolidated, unconfined, high-yield (>100 gallons per minute) aquifer, based on a letter from the New York State Department of Environmental Conservation. The United States Environmental Protection Agency defines a sole source aquifer as one where the aquifer supplies at least 50% of the drinking water for its service area, and there are no reasonable available alternative drinking water sources should the aquifer become contaminated.
Following the completion of multiple studies, including an extensive downstream capacity analysis, LaBella recommended a municipal wastewater collection system along the Carman Road corridor. In addition to mitigating the potential negative impacts on the community’s sole source aquifer, the solution could be a catalyst for:
- Potential additional commercial development
- Potential infill development on building lots which would otherwise not be developable based on current standards and regulations for on-site wastewater management practices
- Redevelopment of environmentally restricted sites
- Encouragement of walkable communities via the potential for mixed-use development thus reducing the carbon footprint.
The Town of Rotterdam championed this collection system. While the Town does own and operate another permitted wastewater treatment facility, it was not feasible to expand this system to include Carman Road. Instead, LaBella proposed that the new wastewater collection system tie into a different, recently constructed system that discharges to the City of Schenectady’s wastewater treatment facility.
The final design included a gravity wastewater collection system along Carman Road with connecting gravity and low-pressure sewer systems. LaBella prepared a successful NYS Environmental Facilities Corporation (EFC) Water Infrastructure Improvement Act (WIIA) grant in 2019, providing $533,000 in funding for the project.
A successful gravity sewer installation meant deep excavations and extensive dewatering operations. Sewer depths ranged from five feet to 18 feet deep, with the pump station over 23 feet deep into the ground. Groundwater conditions continued to cause concern for the sole source aquifer, so the groundwater dewatering plan was modified several times throughout the project.
Dewatering for the pump station required four different dewatering setups over a five-month period to get groundwater to a workable level until the Carman Road pump station was installed and backfilled. Dewatering for the collection system manholes near the pump station required a three-day set up and, after just 24 hours, the groundwater level was sufficient to install the gravity sewer system and structures. The dewatering system remained online for five weeks until the gravity sewer system was fully installed and backfilled.
Construction remains on schedule, slated for completion in 2023. LaBella continues to provide construction and grant administration services.
