Indiana Code Title 5. State and Local Administration § 5-1.2-6-10

Sec. 10. (a) The authority and the department of natural resources may enter into appropriate agreements setting forth the terms and conditions of use of park improvements and the money agreed to be paid at intervals for the use.  The department of natural resources is not obligated to continue the use and make payments under the agreement but shall vacate the improvements if it is shown that:

are unjust and unreasonable considering the value of the improvements.

(b) In determining just and reasonable amounts to be paid for the use of improvements, the authority shall impose and collect money that in the aggregate will be sufficient to pay the expenses of operation, maintenance, and repair of the improvements to the extent that the expenses are not otherwise provided and leave a balance of net income of revenues from the improvements to pay the interest on the bonds as the interest is due and accomplish retirement of the bonds at or before maturity.  If the department of natural resources has made all payments provided in the agreements, the use of improvements covered by the agreements and the sites of the improvements revert to the department of natural resources at the end of the terms of the agreement.