Whenever a benefit district for the purpose of providing fire fighting service has been established under the provisions of Kan. Stat. Ann. § 19-3624 et seq., and the governing body thereof determines that it is in the best interests of the district to place the supervision thereof under a district board of trustees, said governing body may appoint a board of not less than three members and not more than nine members, composed of persons other than members of said governing body, who shall serve at the pleasure of said governing body. The board so established may be vested with all powers vested in said governing body, or such supervisory powers as said governing body may, by resolution, delegate, and the board so appointed may exercise all powers so delegated.