For the purpose of defraying the expenses of the organization of the district, and the care, operation, management, repair and improvement of all canals, ditches, reservoirs and works, including drainage works and including salaries of officers and employees and for rental or charges for water supplied to said district under any contract with owners of other irrigation works, the board may fix rates of tolls and charges and collect the same of all persons using said canal and water for irrigation or other purposes, or may provide, in whole or in part, for the payment of such expenditures by levy of taxes therefor, as hereinbefore provided or by both tolls and taxes. In case the money raised by the sale of bonds issued be insufficient and in case bonds be unavailable for the construction or completion of any works in accordance with plans adopted, it shall be the duty of the board of directors to provide for the completion of said works by causing the levy of a tax therefor in the same manner in which levy of taxes is made for the other purposes provided for in this act.