The nearly century-old breakwater at Port San Luis Harbor is failing and needs to be rebuilt.
Inspections by the Army Corps of Engineers have found that the structure has deteriorated to the point that it is losing its ability to protect the harbor from the prevailing northwesterly swells, said Steve McGrath, harbor director.
Boulders are sloughing off the jetty, and it has several low spots. Without being rebuilt, the breakwater will begin to completely unravel. The consequences of that would be disastrous, McGrath said.
“It’s not an exaggeration to say that if the breakwater failed, the harbor would be inhospitable to pleasure craft, and our land-based facilities would take a beating,” he said.
The breakwater is owned by the Army Corps of Engineers, and that agency is responsible for its maintenance. The Corps will issue a report later this month detailing the condition of the breakwater and what needs to be done to repair it.
The damage to the jetty was discovered by a combination of visual and side-scan sonar inspections.
The breakwater is a string of large, interlocking boulders that extends 1,800 feet from the tip of Point San Luis. It blocks waves arriving from the northwest. Even with the breakwater, the harbor is subject to big swells arriving from the south, primarily during early spring.
Without it, boats would be torn from their open-ocean moorings and powerful waves would pound the Harford and Cal Poly piers and the port’s boat launches.
The exact cost to rebuild the breakwater will not be known until the Corps report is issued later this month, but it is bound to be in the millions of dollars, if not tens of millions of dollars, McGrath said.
The tip of the breakwater was rebuilt in 2005 to repair damage caused by the San Simeon Earthquake. That repair alone cost $1 million.
“It will certainly be many orders of magnitude above that,” McGrath said.
Getting Congress to allocate the money needed for the repairs will require the cooperation of the county’s congressional delegation as well as lobbying by local elected officials. That effort is expected to begin later this year.
“From our perspective, the sooner we can get this done, the better,” McGrath said.
Construction of the breakwater was completed in 1913. It was repaired in 1984 after it was damaged by powerful swells from an El Niño weather event.
It was repaired again after the earthquake. Aside from those two repairs, the breakwater has not been maintained.