The board, in a resolution authorizing the issuance of revenue warrants, may covenant to operate and maintain the facilities producing the revenues pledged for the security of the revenue warrants, may covenant to fix, maintain and collect tolls, charges, rates or fees which will produce revenues sufficient to provide for the payment of the principal of and interest on the revenue warrants and to provide such additional sums for the further security of the revenue warrants as the resolution may prescribe, and may make such other covenants, with respect to insurance, investments of funds, accounting records, independent audits, events of default, limitations upon competitive facilities and any other matters relating to the revenue warrants and their security as the board may deem necessary, convenient or desirable in order better to secure the revenue warrants or to make them more marketable.