2024 marks the third and final year of the Lower Buzzards Bay Sedimentation and Gooseberry Causeway Impact Study (Gooseberry Study for short), spearheaded by the Buzzards Bay Coalition. Answers are emerging as the study nears its conclusion, but severe damage from recent storm surges have really upped the need for this science.

The Gooseberry Study was conceived to help answer a decades old question plaguing this lower portion of Buzzards Bay’s most exposed coast.  Since the 1943 construction of a causeway linking Horseneck Beach to Gooseberry Island, town officials and landowners have questioned whether the causeway is acting like a huge groin – trapping sand on one side and promoting erosion on the other, potentially leading to a host of unintended and serious consequences.

The Buzzards Bay Coalition assembled a renowned group of scientists to use new advances in oceanography to study how water and sand move along the coast, stretching from Little Compton through Westport to Dartmouth. Leading scientists from Boston University, the Woods Hole Group, and the Virginia Institute of Marine Science (VIMS) have come together to search for the answers.

The Gooseberry causeway sits in the middle of this 15 mile stretch of shoreline that has seen dramatic changes over the last few decades. To its east, severe erosion has occurred at Westport’s East Beach, and the inlet to Dartmouth’s Allens Pond seems to be increasingly unstable, which jeopardizes wildlife habitats of an internationally recognized Important Bird Area. The two river systems on either side of the Gooseberry causeway (Westport and Slocums) have increasing sand shoaling, or shallow formations of sand, at their mouths; this impacts the ability of boats to traverse in and out and may trap pollution in these rivers. The team of scientists is working to understand what is driving these changes and if the causeway is playing a role in the changes.

The scientists are pairing water and sediment measurements with sophisticated computer models to tease apart what is happening. During the summers of 2022 and 2023, the study team spent time making measurements along the coast. The measurements included were of sand dunes, interior marshes, currents, and wave conditions in the waters offshore. The team is using these measurements to make sure the computer model produces results that are consistent with what is actually happening in the environment.

“The model simulates water and sediment movement, which depend on a variety of factors including currents, waves, tides, winds, and bottom topography,” shared project lead Zoe Hughes of Boston University. “It’s important to check that the model can recreate what we observe in the real world. That way we can be confident that the model results are sound.

The focus for the project’s final year is using the models to test different scenarios, which will tell the team about what is driving the changes in this stretch of coastline. The different scenarios include whether or not there is a causeway present, and changes between normal conditions and storms of different sizes, including hurricanes.

“We started this project to understand how sand movement is affected by the Gooseberry causeway, which is a static structure we can see, but the environment isn’t static,” remarked Rachel Jakuba, Buzzards Bay Coalition’s Vice President of Bay Science. “Sea level rise and increased storminess due to climate change are man-made changes that are harder to wrap our heads around but are equally impactful as structures such as the causeway.”

As extreme weather becomes the new normal across Buzzards Bay, results from the Gooseberry Causeway Impact Study will be an invaluable tool in creating plans to preserve our communities and our coastline. Armed with the results of this study, community leaders will be able to take action that is both swift and informed.

Stay tuned for this summer when the Research Team will begin releasing findings from the model that will help town and state officials and landowners to make decisions about coastal management.