The order shall fix the day of the election, shall describe the exact location of each project for which bonds are to be issued, shall specify the amount of the bond issue for each project, and shall state in general terms that the money raised from the sale of the bonds for each project shall be used only for the acquisition of rights-of-way for and the construction of, the project for which bonds shall have been issued. If the election is called for the payment of a contract entered into by the commission the order shall state the terms of the contract in such manner as will advise the electors of its contents. Any money raised by means of a bond issue which remains on hand after the acquisition of rights-of-way and construction have been completed, shall be expended in the betterment and maintenance of the project for which the bonds have been voted or for payment on the principal of the bonds.