After the adoption of the budget, the board may not make any other appropriations before the adoption or passage of the next succeeding budget. The board may not, either directly or indirectly, make any contract or do any act which will add to its expenditures or liabilities, in any fiscal year, any thing or sum above the amount provided for in the annual budget for that fiscal year, but the board, by a concurring vote of 2/3 of all the members thereof (this vote to be taken by yeas and nays and entered in the proceedings of the board), may make any expenditures and incur any liability rendered necessary to meet emergencies such as epidemics, fires, unforeseen damages or other catastrophes happening after the annual budget has been passed or adopted. However, the board may at any time after the adoption of the annual budget, by a vote of 2/3 of all the members of the board, pass an additional or supplemental budget, thereby adding appropriations to those made in the annual budget and such supplemental or additional budget shall be regarded as an amendment of the annual budget for that year, but any additional or supplemental appropriations so made may not exceed the amount of moneys which the board estimates it will receive in that year from State appropriations, from federal funds and from any increase in the authorized tax rates over and above the amount of moneys which the board, at the time of the adoption of its annual budget for that year, estimated would be received from those sources. This Section does not prevent the board from providing for and causing to be paid from its funds any charge imposed by law without the action of the board.