Whenever the board, by resolution adopted by a four-fifths vote of all members of the board of a five-ward district, or by a five-sevenths vote of all members of the board of a seven-ward district, finds and determines that any part of the works of the district has been damaged or demolished by reason of fire, flood, earthquake, sabotage, or act of God or the public enemy, and that the cost of repairing or replacing the works so damaged or demolished is too great to be paid out of the ordinary annual income and revenue of the district, and that the public interest requires the incurring of indebtedness for the purposes set forth in the resolution, the board may authorize the incurring of indebtedness for this purpose pursuant to this chapter.