The board of trustees may, in lieu of charging and collecting tolls or in combination with the charging and collection of tolls, levy or assess adjacent property owners or the different supervisors districts, municipalities, agencies, departments, or other instrumentalities assisting in the development of the works authorized herein with an amount of money which, together with other revenues, will provide sufficient funds to carry out the purpose of this chapter. All political subdivisions of this state are hereby authorized and empowered to make such agreements with the board of trustees as are necessary to carry out the purpose of this section. All assessments shall be voluntary and at the discretion of the party or governmental subdivision upon which the assessment is to be levied. All procedures, regulations, commitments, etc., shall be outlined in detail on a resolution by the board of trustees of the authority prior to acceptance by any political subdivision of this state and agencies, commissions, departments, and other instrumentalities thereof.