All unencumbered balances of all appropriations shall revert to the State Treasury at the end of each fiscal year and to the credit of the General Fund or the special fund from which the appropriation or appropriations were made. Appropriations for the purchase of land or the erection of buildings or new constructions or for State Department of Transportation maintenance of roads and bridges on the state highway system shall continue in force until the attainment of the object or the completion of the work for which such appropriations are made.
Ala. Code § 41-4-93 (1975)