The supervisors shall annually at the same time county budgets are prepared adopt a budget for the zone, which budget shall be divided into the following appropriation items: (1) Overhead and administration; (2) maintenance and operation; (3) construction and improvements; and (4) bond retirement and interest. In preparing the budget, the supervisors shall show the total amount to be expended in each appropriation item and the proportionate share of each appropriation item to be paid from each account of the zone.
In preparing the annual budget, the supervisors shall under the appropriation item of construction and improvement list each flood control improvement or stormwater control improvement and the estimated expenditure to be made for each during the ensuing year. The supervisors may at any time during the year, if additional funds become available to the zone, adopt a supplemental budget covering additional authorized improvements.
The zone budget or any supplemental budget shall be approved only after a public hearing, notice of which shall be given as provided by RCW
36.32.120(7).