The board of park and recreation commissioners of each park and recreation district shall annually compile a budget, in form prescribed by the state auditor, for the ensuing calendar year, and which shall, to the extent that anticipated income is actually realized, constitute the appropriations for the district. The budget may include an amount to accumulate a reserve for a stated capital purpose. In compiling the budget, all available funds and anticipated income shall be taken into consideration, including contributions or contractual payments from school districts, cities or towns, county, or any other governmental unit; gifts and donations; special tax levy; assessments; fees and charges; proceeds of bond issues; cumulative reserve funds.