Clam gardens are an ancient aquaculture method implemented by the Indigenous people of northeast Pacific. A clam garden consists of a low rock wall near the shore that is normally submerged, and is only fully exposed at extremely low tides. Over time, the region shoreward of the wall fills in with sediment, increasing favorable habitat for clams. This traditional management technology has been shown to increase clam abundance, size, and growth rates compared to unwalled beaches, providing enhanced food security for Indigenous communities. In recent years, Indigenous communities in the Pacific Northwest have resumed the cultural practice of building, restoring, and tending clam gardens. Specifically, in 2022, the Swinomish Indian Tribal Community (SITC) began constructing what is thought to be the first new clam garden in more than one century in the U.S.

Working with SITC, Kastner will continue studying how water temperature responds to offshore changes in their developing clam garden and adjacent beaches, as well as how long waves important for coastal erosion are impacted by the clam garden wall. As more communities resume the practice of clam gardening, it is important to understand how these systems will be impacted by a changing climate, which will produce more extreme water conditions. Changes in wind patterns may also change how long waves are formed, and interact with a clam garden wall. Funded by NWCASC, Kastner will continue monitoring fieldwork to address these issues, develop a web app to help communities visualize how a clam garden wall may change the offshore wave field near their site, and produce fact sheets on clam garden physics that will be made available to interested communities via the Clam Garden Network.  He looks forward to the opportunity provided by NWCASC to continue this collaboration with SITC.