Upon the completion in any year of the maintenance or improvement work, including annual routine maintenance work, as specified in the plans approved by the board, the local agency shall notify the department, and the department shall inspect the completed work. The department, upon completion of such inspection, shall submit to the board a report as to its findings. Upon a finding that the work has been satisfactorily completed in accordance with the approved plans, the board shall certify for reimbursement 75 percent of any costs incurred per mile of levee if the entire cost incurred per mile of levee is greater than one thousand dollars ($1,000).