Tex. Parks and Wildlife Code § 22.029: PLEDGE OF INCOME.

The department may irrevocably pledge the rents, revenues, and income from the improvements financed by the bonds and from any other revenue-producing facilities or properties of the park, including the fees collected for admission to the park, to the payment of the interest on and the principal of the bonds and may enter into agreements regarding the imposition of charges and the collection, pledge, and disposition of revenue.

Acts 1975, 64th Leg., p. 1405, ch. 545, Sec. 1, eff. Sept. 1, 1975.