Report: Pleasant Bay Could Lose Half Of Intertidal Resources To Sea Level Rise

By: Tim Wood

With a projected sea level rise of between 1.2 and 2.9 feet, Pleasant Bay could lose as much as half of its 392 acres of landside intertidal resource area by 2100, according to a new report sponsored by the Pleasant Bay Alliance.

While the barrier beach that protects the bay from the Atlantic will remain intact, its configuration and rate of inlet formation and evolution will be different than it has in the past. The process of the barrier beach rolling over and moving to the west will keep pace with sea level rise, but the 140- to 150-year cycle of the breaching and regrowth will accelerate, according to the report.

Sea level rise will also cause the Nauset Beach system to experience a loss of ocean-side beach and intertidal zones, resulting in lower due height.

Revetments along the inner shoreline are also likely to have an impact on the barrier beach process, Coastal Geologist Mark Borrelli told an audience at the Chatham Town Hall Annex Thursday evening, which is already beginning to be seen with deep-water areas off Holway Street. Revetments will increase the rate of erosion in other areas and shrink intertidal resource area, which are important for storm protection, pollution filtration and habitat.

The Alliance also released draft guidelines for managing coastal erosion in Pleasant Bay. Coordinator Carole Ridley said these will help towns along the bay make policy decision and protect public resources and infrastructure.

The sea level rise report and erosion guidelines are available on the Alliance website, www.pleasantbay.org.

Watch Thursday's paper for a full report on the study.