Cal. Water Code § 12683
The Los Angeles County Flood Control District shall give assurances satisfactory to the Secretary of War that the local cooperation, required by Section 3 of the act of Congress approved December 22, 1944 (Public, Numbered 534, Seventy-eighth Congress, Second Session) and Section 2 of the act of Congress approved August 18, 1941 (Public, Numbered 228, Seventy-eighth Congress, First Session), will be furnished by the Los Angeles County Flood Control District in connection with the plan for flood control adopted and authorized in Section 12682.