The board of directors of the district is hereby authorized to provide by resolution for the issuance of refunding bonds of the district for the purpose of refunding any bonds then outstanding and issued under authority of this article, including the payment of any redemption premium thereon and any interest accrued or to accrue to the date of redemption of such bonds. The issuance of such refunding bonds, the maturity and other details thereof, and the rights, duties, and obligations of the board of directors and of the district in respect to such bonds shall be governed by the provisions of this article, insofar as they are applicable. In no event shall such bonds mature over a period of time exceeding forty years from January 1, 1961. No such refunding bonds shall be issued and delivered more than five years in advance of the date when the bonds to be refunded are redeemable, and not until such outstanding bonds shall have been called for redemption and notice thereof provided for as therein required. The proceeds of any such refunding bonds shall be deposited with the trustee named in the bonds to be refunded and, pending the application thereof to the payment and redemption of the bonds to be refunded, shall be invested and reinvested in obligations of or guaranteed by the United States of America and maturing or being redeemable at or prior to the time when the said bond proceeds are required for the redemption of the bonds to be refunded. All interest or other increment received on or on account of all such investments shall be deposited in and become a part of the fund held by the trustee for the payment and redemption of such refunding bonds.