Either the resolution providing for the issuance of bonds or the trust indenture may contain such provisions for protecting and enforcing the rights and remedies of the bondholders as may be reasonable and proper. No enumeration of particular powers granted may be construed to impair any general grant of power contained in this chapter. All expenses incurred in carrying out the provisions of the resolution or trust indenture may be treated as a part of the cost of maintenance, operation, and repair of the works affected by the resolution or trust indenture.