The Secretary, in cooperation with the Metropolitan Water District of Southern California and the Main San Gabriel Water Quality Authority or a successor public agency, is authorized to participate in the design, planning and construction of a conjunctive-use facility designed to improve the water quality in the San Gabriel groundwater basin and allow the utilization of the basin as a water storage facility; Provided, That this authority shall not be construed to limit the authority of the United States under any other Federal statute to pursue remedial actions or recovery of costs for work performed pursuant to this subsection.

The Secretary’s share of costs associated with the project described in subsection (a) shall not exceed 25 per centum of the total. The Secretary shall not provide funds for the operation or maintenance of the project.