In the event of any such board of directors taking over such duties it shall become the duty of the board of directors, on or before the first day of September of each year, to determine the amount of money required to meet the obligations, maintenance, operating and current expenses for the ensuing year, and to fix the rate per acre of levy necessary to provide the amount of money required to pay the interest and principal of the bonds of said district as the same shall become due; also, to fix the rate per acre necessary to provide for the amount of money required for any other purposes under laws providing for the creating and operation of irrigation districts, and which are to be raised by the levy of taxes upon the lands of said district, and to certify the same to the assessor-collector of said district. The rate of levy necessary to raise the required amount of money for said district may be increased 15% to cover delinquencies.