WWTF Climate Resilience Assessment & Upgrade

The Town of Seabrook identified key wastewater treatment components at risk from projected sea‑level rise in its Coastal Hazards and Adaptation Master Plan chapter.

This project focused on the town’s critical wastewater treatment infrastructure, which collects and treats domestic, commercial, and industrial wastewater community‑wide.

The wastewater treatment facility (WWTF) is located on Wright’s Island, a small area within the salt marsh along the New Hampshire/Massachusetts border, accessible via a single-lane causeway from Route 286. Its isolation makes the WWTF vulnerable to sea level rise and coastal surge, posing a public health risk during disruptions. This project aims to assess site vulnerabilities, identify options for enhancing resiliency, and deliver final design and pre-construction services.

The project also includes public communication and outreach to engage residents in discussions about climate change and the WWTF assessment in Seabrook, using an approach designed to be easily replicated by other coastal New Hampshire communities.

The first phase involved a resilience study to identify current and projected flooding risks from sea level rise and storm surge; conduct site‑specific evaluations of these hazards; incorporate new groundwater‑rise science; develop design concepts, permitting strategies, and cost estimates for four WWTF resiliency options; and engage over 50 residents through a public engagement strategy on climate threats and emergency procedures.

The following phase advanced the recommendations by conducting a site survey to confirm dimensions and elevations; developing the basis of design report; designing the mechanical, electrical, civil, and controls components for the chosen alternative; estimating construction costs and obtaining necessary permits; developing standard operating procedures for the new equipment; conducting stakeholder engagement; and preparing quarterly reports for grant compliance.

Construction of the adaptation measures for the WWTF is anticipated to begin in 2026.