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More About
Forge River Watershed Project 

  • The Forge River Watershed Sewer Project is one of four related projects included in the Suffolk County Coastal Resiliency Initiative. These projects are located in the Forge, Carlls, Connetquot, and Patchogue River watersheds,  as well as the Southwest Sewer District No. 3.

  • The primary purpose of these projects is to mitigate the short-term and repeated adverse impacts to people and property caused by onsite sewer system failures that result mainly from heavy rainfall and tidal flooding. The secondary purpose is to address the long-term impact of nitrogen pollution caused by onsite sewer system failures on surface waters and coastal wetlands, such as rivers and bays.

  • The failure of multiple onsite sewer systems on residential and commercial parcels causes public health risks from uncontrolled wastewater discharges, degrading the ecosystems that protect shoreline against storm surge, and threatening the quality of drinking water.

  • The Forge River Watershed Sewer Project proposes to connect hundreds of properties in the Mastic-Shirley area to a new sewer collection system that will flow to a new advanced wastewater treatment facility (that would include advanced nitrogen treatment). 

  • A new sewer district, the Suffolk County Sewer District No.27 - Forge River, would be established. The project proposes to decommission hundreds of onsite systems on residential and commercial parcels within the project area.

  • Over many decades, septic system failures, as well as cesspools, agricultural uses and runoff, have created a nitrogen pollution crisis, degrading the quality of both our surface water, including the Forge River and the Great South Bay, and groundwater, which is our source for drinking water. 

  • Tests have shown that the Forge River is one of the most polluted waterways in Suffolk County. Groundwater levels of nitrogen in the Forge River area are already at the maximum contaminant level for drinking water, and nitrogen levels are projected to continue to increase if wastewater infrastructure is not upgraded, leaving the community vulnerable and at risk of contaminated drinking water.

  • More than 70 percent of Suffolk County’s 1.5 million residents lack connections to advanced wastewater treatment infrastructure, relying instead on on-site septic systems. Many on-site wastewater systems in the project area are outdated and failing, causing untreated effluent to be released into surrounding soils. 

  • Older systems that have not been maintained are at a higher risk of failing, leading to frequent sewage overflows and backups resulting from clogged systems.  While the exact number of system failures can’t be quantified, many failed during Hurricane Sandy and will continue to fail during future storms.

  • During Superstorm Sandy, many on-site septic systems were flooded by the rising groundwater, which allowed for a direct mix of sanitary wastewater into groundwater and caused solids to wash out of the septic systems. Contaminants entered groundwater and surface waters, causing public health and water quality hazards.

  • The impacts of Superstorm Sandy also exacerbated the already rising nitrogen pollution from failing septic and cesspools along river corridors into the Great South Bay; this has not only caused a water quality crisis, but seriously eroded the coastal wetlands, which have been scientifically proven to reduce vulnerability from storm surge.

  • This new county sewer district will be built in phases, with Phases 1 and 2 including areas within the densely developed residential and commercial area bounded by the Sunrise Highway to the north, the Poospatuck Creek to the south, the William Floyd Parkway to the west and the Forge River and its tributaries to the east.

  • In response to public comments, the original Phases 1 and 2 project area described above was expanded to include a third and fourth phase, along the west shore of the Forge River.  Currently, only Phases 1 and 2 are proposed for funding and will be designed and built first.  However, Phase 3 has been included in the environmental review and planning processes so that it can also be constructed when funding is made available.

  • The engineering and design phase of the project (Phase 1 and 2) began in late 2016. 

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