The San Bernardino County Flood Control District and the Riverside County Flood Control and Water Conservation District shall give assurances satisfactory to the Secretary of the Army that the local cooperation, required by Section 201 of the act of Congress approved May 17, 1950, Public Law 516, Eighty-first Congress, Second Session, will be furnished by the districts in connection with the plan of improvement for flood control adopted and authorized in Section 12679.