The board of supervisors of any county, the governing authorities of any municipality, the board of trustees of any public school district and the governing authorities of any other political subdivisions are hereby authorized and empowered to expend public funds and to utilize public equipment and facilities for the purposes of evacuation of persons endangered and for the protection of private property damaged or threatened by the flooding of the Spring of 1975 in any area declared by the governor to be under a state of emergency because of said flooding; provided, further, that the authority and powers set forth by this section shall expire on September 30, 1975.