Ala. Code § 45-8A-23.138: Surplus.

Surplus shall include:

(a) Revenue receipts made available by the lapsing of unencumbered appropriation balances at the beginning of the budget year;

(b) Receipts from unanticipated miscellaneous revenues of the preceding fiscal year;

(c) Receipts from anticipated miscellaneous revenues of the preceding fiscal year in excess of the estimates in the budget;

(d) Receipts during the previous fiscal year from taxes or liens against which a complete reserve has been established.