The proceeds derived from the bonds to be so sold shall be paid to the treasurer of the district and shall be set aside from and not commingled with any other funds of the district, shall be designated tributary compliance funds, and shall be used solely for the purpose of enabling the board of directors of that district to comply with the obligations imposed on and assumed by it in the contracts and agreements made with the United States of America or any other federal agency relating to the construction and perpetual operation and maintenance of the flood control works provided for in the adopted and authorized project.