The official legislative body of any governmental agency is authorized to set aside a special sinking fund in the office of the treasurer of the governmental agency for the payment of anticipation warrants authorized by and issued under the provisions of this part 3 and for the payment of interest due on such warrants; except that the general income of the governmental agency shall not be pledged for the payment of the principal of the warrants and interest thereon. The treasurer of the governmental agency shall deposit in said sinking fund all rents, royalties, fees, rates, and charges derived from or rendered by the project.
C.R.S. § 30-20-306