The authority shall pay out of the proceeds from the sale of any of the bonds all expenses which the board of directors may deem necessary or advantageous in connection with the sale and issuance of the bonds. The proceeds from the sale of all bonds, other than refunding bonds, remaining after paying the expenses of their sale and issuance shall be turned in to the State Treasury, shall be carried in a special fund to be designated the Coosa Valley Development Authority fund, and shall be subject to be drawn on by the authority, upon approval by the Governor, but solely for the purpose of discharging the duties and obligations undertaken by the authority in connection with the waterway project. The proceeds from the sale of any refunding bonds remaining after the expense of their issuance shall be used only for the purpose of refunding the principal of outstanding bonds issued hereunder and of paying any premium that may be necessary to be paid in order to redeem or retire the bonds to be refunded.

Any portion of the proceeds derived from the sale of any of the bonds which the board of directors of the authority may determine is not then needed for any of the purposes for which the bonds are authorized to be issued shall, on order of the authority, be invested by the State Treasurer in any securities that are direct general obligations of the United States or the principal of and interest on which are unconditionally and irrevocably guaranteed by the United States. Any such securities may, at any time and from time to time, on order of the authority, be sold or otherwise converted by the State Treasurer into cash. The income derived from any such investments shall be added to and treated as a part of the Coosa Valley Development Authority Fund.