The water quality at Mothers Beach in Marina del Rey is set be improved, as a new project has begun to help rid the beach water of bacteria, using propellers mounted under new aluminum platforms to increase circulation of the water.

Construction crews have been working on a Panay Way parking lot adjacent to Mothers Beach, where they are building a new dock that will be used as part of the $916,000 project to cleanse the beach water, Los Angeles County officials said.

The project is being funded by the county.

As part of the project, construction crews will replace the “dilapidated” dock on the Palawan Way side of the beach — which is used for the Marina WaterBus — with a new aluminum dock with two platforms, said Steve Penn, of the Department of Beaches and Harbors Planning Division.

Two propellers will be mounted underneath the new dock to create circulation of the water, he said.

By circulating the water, the two “paddle-type fans” will help bring any bacteria to the surface, where the sun can break it down, county Department of Beaches and Harbors spokeswoman Dusty Crane said.

“What seems to be an issue is that bacteria gets into the water,” Crane said. “We’ve been looking at different methods to try and improve the water quality at Marina Beach.”

A survey indicated that the bacteria level of the water has remained “pretty good” during the dry season, but county officials have become concerned about the water quality due to the high volume of visitors and children at the beach, Penn said.

“It’s quite the project and we’ve been working on it for a while,” Crane said. “It isn’t the perfect solution, but we’re hoping it will help keep the water quality improved.”

County officials have tried various methods in the past to improve the water quality of the beach, such as using aerating jets, but those efforts were unsuccessful and costly, Crane said.

The project was initially scheduled to begin in July but was held off until early September to allow for the WaterBus service to end, she said.

County officials expect the project work to be completed by the end of the month.