Harbor District attempts to tackle coastal erosion

A 2015 study found the erosion rate from Pillar Point to Arroyo de en Medio to be 1.64 feet per year, which is 1.4 feet greater than the typical background erosion rate, Pruett said. He will later be presenting information to sea rise resilience agency OneShoreline. 

“The study found that the breakwaters are leading to a dramatic increase in the erosion rate,” he said. 

The Harbor District has two upcoming projects in various beginning stages that its officials hope will be able to address the issue in the way past beach and trail restorations have not. 

One, the Princeton Shoreline project, would try to mitigate the erosion that has affected homes, businesses and infrastructure in Princeton. The sea level encroachment and erosion in the area has become so dire that local residents have attempted to stop it with concrete, wood, rocks and bricks, Pruett said. 

“All these efforts failed,” he said. “They failed because the root cause of the erosion had not been addressed.” 

The Harbor District held a focus group study session on the issue this week. It now wants to work with the U.S. Army Corps to come up with a real solution, which would likely be a hybrid of offshore structures or even a concrete or steel retaining wall, as well as nature-based solutions. The goal would be to keep the project under $15 million, allowing the Army Corps to bypass congressional approval, Pruett said. 

The district is also working to gather funding for a larger, $3 million Army Corps study that could identify solutions to the breakwater issue at large, Pruett said. If the study finds feasible solutions to the issue, it could include keeping the breakwater in place and either constructing a submerged rock reef off of Surfer’s Beach or enhancing and raising the existing rock reef, Pruett said.

“It’s the hope that the result of this project, once completed, the root cause of existing coastal erosion will be addressed while maintaining the vital harbor of safe refuge,” he said. 

While the prior Army Corps study did find evidence of significant erosion, it also did not find any potential solutions to be economically feasible, a conclusion Pruett said was flawed because it didn’t take into account damage to Highway 1 or the coastal trail. 

During the meeting, Pruett also presented efforts that had previously been undertaken to restore beaches and trails in the area, including a recent dredging project that moved sand from inside the harbor to the adjacent, eroding Surfers Beach and reworking the stormwater system and improving trails along West Trail. 

Both of those projects experienced success, Pruett said, but emphasized that they did not fully address the root causes of erosion.