91.690. 1. At or before the issuance of any such bonds thegoverning body shall by ordinance create a sinking fund for thepayment of the bonds and the interest thereon and the payment ofthe charges of banks or trust companies for making payment ofsuch bonds or interest, and shall set aside and pledge asufficient amount of the net revenues of the works, herebydefined to mean the revenues of the works remaining after thepayment of the reasonable expense of operation, repair andmaintenance, such amount to be paid by the board into saidsinking fund at intervals to be determined by ordinance prior toissuance of the bonds, for
(1) The interest upon such bonds as such interest shall falldue; and
(2) The necessary fiscal agency charges for paying bonds andinterest;
(3) The payment of the bonds as they fall due, or, if allbonds mature at one time, the proper maintenance of a sinkingfund sufficient for the payment thereof at such time; and
(4) A margin for safety and for the payment of premiums uponbonds retired by call or purchase as herein provided, whichmargin, together with any unused surplus of such margin carriedforward from the preceding year, shall equal ten percent of allother amounts so required to be paid into the sinking fund.
2. Such required payments shall constitute a first chargeupon all the net revenues of the undertakings. Prior to theissuance of the bonds, the board may by ordinance be given theright to use such sinking fund or any part thereof in thepurchase of any of the outstanding bonds payable therefrom at themarket price thereof, but not exceeding the price, if any, atwhich the same shall in the same year be payable or redeemableand all bonds redeemed or purchased shall forthwith be canceledand shall not again be issued. After the payment into thesinking fund as herein required, the board may at any time in itsdiscretion transfer all or any part of the balance of the netrevenue, after reserving an amount deemed by the board sufficientfor operation, repair and maintenance for an ensuing period ofnot less than twelve months and for depreciation, into thesinking fund or into a fund for extensions, betterments andadditions to the works.
(L. 1941 p. 493 ยง 7)