The Counties of Santa Clara, Santa Cruz, and San Benito and the Monterey County Flood Control and Water Conservation 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), will be furnished by the counties and the district in connection with the flood control project authorized and adopted in Section 12685.