Costa Canal. (5) District The term District means the Contra Costa Water District, a political subdivision of the State of California. (6) Rock Slough fish screen facility (A) In general The term Rock Slough fish screen facility means the fish screen facility at the Rock Slough intake to the Contra Costa Canal. (B) Inclusions The term Rock Slough fish screen facility includes the screen structure, rake cleaning system, and accessory structures integral to the screen function of the Rock Slough fish screen facility, as required under the Central Valley Project Improvement Act ( Public Law 102–575