Using hydraulic pumps to move sand along the narrowing beach that keeps homes on The Peninsula safe from the Pacific Ocean could be a viable alternative for Long Beach going forward, however, it could cost the city an unknown amount of money to invest in the necessary machinery to keep displaced sand circulating.
The city’s Marine Advisory Commission was presented the findings of a pilot program carried out earlier this year that deployed hydraulic pumps to move sand from the northwestern end of the peninsula to the southeastern edge near the entrance to Alamitos Bay.
The pumps moved sand about a mile down the shore to an area of beach that has been under constant assault by seawater erosion, forcing the city to move sand back to the site with trucks and tractors.
“It may not be the most liked approach but the bottom line is that it does effectively move the sand, it’s cost-effective and well documented,” said Steve Cappellino, a senior partner with Anchor QEA which worked on the pilot program.
During the pilot program, the sand was moved from a harvesting site on the northern portion of the peninsula through a plastic pipe that dumped the sand into strategic points along the Southern portion of the beach to restore its inventory of sand.
The beach, due to a confluence of factors including jetties and the city’s breakwater, is eroded by a circular motion that drives the sand up the shore to the northern end of the peninsula.
Cappellino said that while the project did prove to eventually be effective, there were some snags that could require additional investments by the city to improve efficiencies if it were to move forward with this approach in the future.
One of the issues is that deploying the machinery requires some time to set up and with the sudden onset of a storm using the pumps wouldn’t entirely eliminate the need for trucks on the beach. It also would require a lot of manpower and deploying the pumps would require the city to purchase an excavator so that it would have one on hand when it’s needed instead of having to rent one, Cappellino said.
The pipe also became clogged at one point when the pump began to push soil through it, something that could take days to fix.
“We learned that the hard way,” Cappellino said.
Thursday was the first public presentation of the city’s pilot project and it likely faces a number of future public meetings before any kind of definitive action is taken. Elvira Hallinan, a manager in the city’s Marinas and Beaches bureau, cautioned commissioners that while no action would be taken that future moves could be constrained by a decreasing Tidelands budget.
“We are in a pandemic and there is less money coming into Tidelands so there’s nothing that we can commit to right now but, this is something that’s at the forefront of city leaders’ minds,” Hallinan said.
One solution that could take the trucks and tractors off the beach and still use the hydraulic pumping technology deployed during the pilot program could see the city place small barges near the mouth of Alamitos Bay.
Sand is already deposited there by currents pushing sand north from Seal Beach, Cappellino said, and a solution could be to dig a large “sand trap”—a hole where that sand would settle into naturally—at the mouth of the bay and have the pumps harvest that sand and pump it onto the peninsula.
“You’re basically helping nature do what it wants to by keeping it going down the beach,” he said.
Taking that approach could relieve some of the issues the pilot program ran into like the time required to place the pumps, tidal issues and the distance the sand would need to be pumped to replenish the affected area of beach. It would also simultaneously dredge the opening to the bay.