Posted on December 8, 2020
The Westchester Bay Homeowners and Seagate Lagoon Associations sought a permit for structural repairs to an existing bulkhead in order to protect the residential development.
SAN DIEGO—The California Coastal Commission at its Nov. 5 meeting approved a coastal development permit sought by the Westchester Bay Homeowners and Seagate Lagoon Associations to make structural repairs to a bulkhead in Huntington Harbour.
The Westchester Bay Homeowners and Seagate Lagoon Associations sought a permit to complete structural repairs to a combined 135-foot portion of an existing, 5,198-foot bulkhead at eight distinct locations. The proposed repairs include timber pile repairs placement of shore guard rigid vinyl sheetpiles flush with the existing bulkhead footings, pumping concrete grouting behind the proposed sheetpiles to eliminate exposure of the timber piles to the elements, and removal of existing concrete overpour to restore harbor bottom habitat.
According to Coastal Commission findings, erosion beneath the footings resulted in a gap between the existing footing and the natural mudline. This erosion resulted from tidal currents and exchange, vessel prop wash, and settlement, among other factors. The resulting gap has allowed aquatic lifeforms to burrow beneath the footings, resulting in the loss of footing support causing wall instability. This condition has also caused marine organisms to damage the timber piles. According to the findings, if protective measures are not implemented, additional damage to the bulkhead will result, causing potential failure of the bulkhead and damage to the existing, pre-coastal upland structures, including, the adjacent residences.
Coastal Commission staff deemed the bulkhead repair project necessary to protect the existing, pre-coastal residential development.
The project aims to restore the foundation of the bulkhead and to limit future erosion which may jeopardize the bulkhead’s structural integrity and ability to support the existing residences. The Coastal Act requires the commission to approve such projects when necessary to protect existing structures and when designed to eliminate or mitigate adverse impacts.
The commission unanimously approved the permit with 10 conditions. As proposed, and as conditioned, measures will be in place to protect water quality during and after construction. Also, as conditioned, surveys will be conducted pre- and post- construction to assure that any unanticipated impacts to eelgrass that may occur are addressed and to assure that the project will not result in the spread of the invasive algae Caulerpa taxifolia. A pre-construction eelgrass survey conducted on Oct. 25, 2019 found a total of 702.5 square feet of eelgrass present in the project vicinity. However, no eelgrass was found within the areas of the proposed repairs.
Measures to address the use of plastic in the marine environment are also required as special conditions.