(1) The payment of operating expenses of the port authority;
(2) The payment of the interest on the bonds issued pursuant to this chapter and the principal of such bonds, as they severally mature, and/or payments into sinking fund reserves for this purpose;
(3) The establishment of necessary reserves for contingencies, depreciation, maintenance, replacement of port, storage and transfer facilities and any and all other facilities or other purposes, as may be required under any bond indenture or as the board may deem necessary or desirable; and
(4) Any revenue or proceeds remaining after all the above items have been provided for shall be held and used for the further development of and for additions to the authority facilities and for the acquisition or construction of new facilities that may become necessary or desirable to further the purposes of this chapter. None of such revenue shall go into the general funds of the participating counties, except as may be directed by the board.