Forge River Watershed Sewer Project

Suffolk County, New York, relies heavily on onsite waste disposal systems consisting of septic systems and cesspools, with nearly 70% of its 1.5 million residents using them for wastewater disposal. In the Mastic-Shirley area, these systems have deteriorated over decades, often failing during heavy rains or coastal storms like Superstorm Sandy in 2012. These failures have led to increased nitrogen levels in groundwater and surface waters like the Forge River, causing significant coastal degradation and threatening the environment and public health. 

To address these issues, the Suffolk County Department of Public Works launched the Forge River Watershed Sewer Project, the county’s largest sewer infrastructure initiative in four decades. This $228 million project will reduce nitrogen pollution, restore the health of local waterways, and enhance coastal resilience for thousands of residents. It is a critical component of the broader $408.8 million Suffolk County Coastal Resiliency Initiative. 

Our firm delivered comprehensive planning, design, and construction management services for a new sewer collection and conveyance system and a 1 million gallons per day advanced wastewater treatment facility (AWTF) to reliably treat wastewater and reduce environmental impact. 

Using building information modeling (BIM), we created detailed digital models that improved interdisciplinary collaboration and streamlined construction. Geographic information system (GIS) tools helped manage infrastructure data across the design and construction phases, optimizing workflows and enhancing project execution. 

We led an extensive public outreach campaign that included open houses, informational flyers, and a dedicated project website. These efforts built trust, addressed community concerns, and culminated in a successful public referendum to create a new sewer district. 

Our team produced engineering reports and detailed designs for the low-pressure collection system and AWTF. Property investigations were conducted to determine optimal installation points for grinder pump units. We also secured required regulatory permits and oversaw construction contracts across nine bid packages. 

Construction milestones include:

• AWTF construction: 2022–2025.
• Sewer system installation: 2022–2024.
• Grinder pump installations and home connections: 2024–anticipated 2026.

When complete, the project will service approximately 2,450 parcels within the newly created sewer district, eliminate reliance on failing onsite waste disposal systems, and protect Long Island’s vulnerable coastlines for generations by ensuring reliable sewage treatment plant operations and delivering clean water back into the environment.