Cal. Wat. Code § 12585.1
The costs of local co-operation shall include, as to projects specifically adopted and authorized by the Congress and the Legislature, costs hereafter incurred prior, as well as subsequent, to Congressional authorization but subsequent to submission of the project report by the Secretary of the Army or other authorized official to the Congress for project authorization; but such co-operation shall apply only to costs incurred for the project as finally authorized by the Congress and the State, and such costs shall not be eligible for reimbursement by the State until after federal and state authorization and after the appropriation of construction funds by the Congress.
As to small flood control projects undertaken by the United States Corps of Engineers pursuant to Section 205 of the Flood Control Act of 1948 (Public Law 858, Eightieth Congress, 2nd Session, approved June 30, 1948), as amended, costs of local co-operation shall include costs incurred after submission of the design memorandum to the Chief of Engineers, if an allocation of funds for the project is thereafter made by the Chief of Engineers, and such costs shall be limited to costs incurred for the project as finally approved by the Chief of Engineers.
Ca. Water Code § 12585.1