Wright-Pierce’s Targeted Watershed Management Plan (TWMP) facilitated a successful collaborative approach to cleaning up nitrogen contamination in Cape Cod’s Pleasant Bay, earning an EPA Environmental Merit Award for the four watershed towns.


Pleasant Bay is the largest estuary on the Cape and its watershed spans four towns – Brewster, Chatham, Harwich and Orleans. Nitrogen contamination in Cape Cod’s coastal embayments has led to excessive algae growth, with negative impacts on fishing, swimming and critical habitats. The sources of the nitrogen, principally septic systems, golf course fertilization and stormwater disposal, are located throughout the coastal watersheds, irrespective of town boundaries. The Pleasant Bay Alliance was formed by the four towns to coordinate the resource management efforts for the Bay.

The Alliance hired Wright-Pierce to combine the nitrogen control plans of the four towns into a Targeted Watershed Management Plan. This document was tailored to match the requirements of a new state permitting approach that empowers towns to work together and with the state Department of Environmental Protection, as watersheds, rather than as individual towns.

The Targeted Watershed Management Plan

The TWMP allows towns to try innovative restoration approaches across boundaries. The Plan sets forth an implementation schedule and considers shared facilities and the trading of nitrogen credits among the towns. The TWMP also identifies the methods by which towns can gain credit for the use of non-traditional nitrogen control approaches, such as fertigation, aquaculture and permeable reactors. The graph below summarizes the intended reliance on non-traditional technologies.

All four towns signed an inter-municipal agreement, based on the TWMP prepared by Wright-Pierce, allowing DEP to issue the first-of-its-kind Watershed Permit. The Watershed Permit allows the towns to acknowledge their relative contributions to the nitrogen loading and empowers them to find best practices for managing it, and to install and obtain nitrogen removal credit for innovative treatment methods. Wright-Pierce is also assisting with the permitting of these non-traditional technologies.

Awarding A Watershed-Based Approach

In its annual awards program, EPA recognized that the success of restoring Cape Cod’s waterways depends on trailblazers like the Pleasant Bay Alliance and its towns. The towns and the Alliance were presented an Environmental Merit Award by EPA at a formal ceremony at Faneuil Hall in Boston in September 2018. To facilitate the implementation of the Pleasant Bay Watershed Permit, EPA also awarded the Alliance $250,000 under the Southeast New England Program.

Often, environmental challenges require thoughtful collaborative problem solving, and the Pleasant Bay project is a great example. Wright-Pierce engineers are proud to have a role in this effort to foster overall water quality in Cape Cod’s Pleasant Bay.

If you have questions or comments related to this Wright-Pierce project or would like to learn more, please contact us today.