Agencies Present Initial Findings of Surfer's Beach Erosion Study

U.S. Army Corps and Harbor District discuss erosion of beach and bluffs in El Granada.

At a public meeting held yesterday at the Half Moon Bay Yacht Club, the U.S. Army Corps of Engineers, in partnership with , presented the initial findings and study approach of the North Half Moon Bay Shoreline Improvement Project, which seeks to provide a plan and solution to alleviating the continual beach loss and bluff erosion at Surfer’s Beach in El Granada.

Peter Grenell, General Manager for San Mateo County Harbor District, and Tom Kendall, chief of the Planning branch of the U.S. Army Corps of Engineers - San Francisco District gave welcoming remarks to a room full of concerned citizens as well as agency members from the San Mateo County Planning Commission, Coastal Commission, Surfrider Foundation, and more.

The three-hour meeting addressed possible causes for the erosion, steps in the planning process, and how the mitigation of shore damages can be initiated as a Continuing Authorities Program (CAP) Section 111 Project, which allots up to $5 million for reducing the erosion to a level that would exist regardless of a federal navigation project. That federal navigation project is the breakwater, otherwise referred to by locals as the jetty at Surfer’s Beach, which was built in the 1960s by the Army Corps to form the harbor.

“The $5 million is the ceiling to stay within the authority to do the study, design and construction itself. It’s our hope to stay within that limit. If we go beyond the authority, then it’s going to take longer and may need to go back for more money,” said Kendall.

Yesterday’s meeting tackled the many possible contributing factors for the shore damage at the El Granada beach, including ground water, rain runoff, sediment discharge from creeks, and extreme winter storms. But after defining the problem over the past couple of years, it’s become more apparent that the wave reflection off the breakwater is the biggest cause of the erosion as sand from the beach that would otherwise provide a buffer to protect the bluffs is being pulled away to the harbor, Kendall said.

“The erosion is definitely from a lot of different processes happening at the same time. Prior to the breakwater there was erosion, but the breakwater has contributed to both the beach loss and bluff erosion at Surfer’s Beach by taking sand from the beach and depositing it inside the harbor,” said Kendall, who credits Grenell for initially bringing the erosion problem and its possible cause — being the breakwater — to their attention.

Indeed, the major effect of putting in the breakwater is that there is more sand on the harbor side and not on the Surfer's Beach side. “But looking at moving the sand from one end of the harbor back to the beach is not going to solve the bluff problem most likely,” said Kendall, who admitted that there are many possible solutions but at this point in the process are not ready to formulate alternatives.

As the non-federal sponsor, the San Mateo County Harbor District shares in the costs as prescribed in the Section 111 legislation.

New congressional authorization is not needed unless the federal funding limit is exceeded.

“If we can stay on the federal side, then the approval levels of the project will be out West, staying within that $5 million range,” explains Kendall. “But if the solution we recommend is going to be more expensive than this, then we will be making trips out to Washington.”

By March 14, 2011, the U.S. Army Corps hopes to initiate environmental assessment and economic analysis and receive nonfederal funding from the Harbor District.

Before the 1959-1961 construction of the outer breakwater, the bay had a stable spiral shape shoreline comprising a continuous sandy beach. Not so today. U.S. Army Corps coastal engineer Lisa Andes showed an aerial shot of the beach in 1956, depicting a sandy face of the beach, a contrast to a 2009 photo that barely registers a strip of beach.

The presentation by Andes also validated that the erosion rate along the shoreline from Pillar Point to Miramontes Point has indeed accelerated since the Army Corps built the breakwater to form the harbor. She outlined 30-day scenarios that assessed the sediment depositions and circulation patterns, showing quite a bit of sediment movement during the winter. Her study was able to calculate the changes in bed elevation and showed a lot of change and erosion along Surfer’s Beach.

“When beach sand is stripped away, there is more energy to attack the beach and bluffs,” Andes said.

Still, there are many steps in the initial planning process that need to happen before going into the preconstruction design phase. Army Corps planner John Dingler took the floor at the meeting and presented the six-step planning process.

Step one, defining the problems and opportunities, has been done already, he said.

“We are now in the feasibility phase, which could be a 2 to 3 year period,” said Dingler.

This phase takes into account the inventory of the physical processes, gathering information and looking at external and internal factors that influence the study environment.

Next, formulating alternative plans will be on the table and from there “we’ll develop the plan, evaluate it and do a comparison before selecting a plan,” said Dingler. “If it’s all OK by the chief engineer, we’ll go into the preconstruction design phase.”

Still, the last phase has to be cost effective, environmentally sound, technically feasible and socially and politically sound, said project manager Irene Lee. “Once we meet this goal, then we can move forward in a year or less.”

“This is hard to achieve and takes time, so this is what we are working toward as the end result. This process is to ensure that our plan is a good plan because there are always unknown things that come up like when we built this breakwater, we didn’t anticipate what would happen. We want to make sure the money is well spent and a positive outcome is what we expect,” said Kendall, who adds that overall timeline for a project like this, from beginning to end, could take anywhere from four to 10 years.

In the meantime, El Granada citizens are concerned with what they’ve witnessed over the course of many years: accelerated erosion of the area, which in some cases is eating up two to three feet of coastline a year. Posts, guardrails, parking areas, and chunks of land are all gone along that stretch of coast, and the Highway I embankment is now being encroached upon.

One community member proposed pumping the sand from the harbor back over to Surfer’s Beach and observe the effects of that over time. Another El Granada resident noted that he, too, has seen two to three feet of erosion a year — and sometimes even more — on a long-term average ever since the breakwater was built. Another person voiced her concern about how impatient the community has become with the project and wondered how long it was going to take before something is done.

“At this point, we just wanted to show you what we’ve done so far,” said Dingler. “As we formulate alternatives, the public is welcome to participate and as we move into formulating alternative plans, there will be move opportunities to convene like this.”

One member suggested that the community should come together and give input to the Army Corps process and look at integration opportunities with other agencies for funding.

Kendall concurred that the Army Corps is limited by time and funding and so the community was encouraged to find other ways to talk about the project within the parameters of Section 111 in order to keep things moving along.

“We can’t put a bluff back to historical dimensions, but we can bring a beach back that would help protect the bluff,” said Kendall. “We’re going to make life on the bluffs a bit better, but won’t be able to fully address every concern.”

Cid June 07, 2011 at 03:49 PM
I would have liked to heard the entire presentation, but could not make that meeting time. Was there any mention of where the silt would be disposed of, once removed from the harbor? Have they tested the built-up sand that will need to be dredged from the harbor for any toxic residues in the sediment? Were there any plans to buttress the shorelne against further erosion while they make the 4-10 year "fix" become a reality? In the big picture, 5 million doesn't seem like much. Were any similar case studies put forth as to cost/benefit analysis?


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