The board of trustees shall, at any time after March 1 of each fiscal year, have power, by a two-thirds vote of all the members of such body, to authorize the making of transfers within a department or between departments of sums of money appropriated for one corporate object or function to another corporate object or function. Any such action by the board of trustees shall be entered in the proceedings of the board. No appropriation for any object or function shall be reduced below an amount sufficient to cover all unliquidated and outstanding contracts or obligations certified from or against the appropriation for such purpose.
     In addition to the contributions required under § 13-503 of the Illinois Pension Code, the board of trustees, by a two-thirds vote of all its members, may transfer the interest earned on any moneys of the district as well as revenue from any lawfully available source into the district’s fund or funds that are most in need of the interest income or revenue from any lawfully available source, or the Metropolitan Water Reclamation District Retirement Fund. This authority does not apply to any interest that has been earmarked or restricted by the board for a designated purpose. This authority does not apply to any interest earned on any funds for purposes of the Metropolitan Water Reclamation District Retirement Fund or Reserve Claim Fund.
     The board of trustees, by a two-thirds vote of all its members, may transfer fund balances between its Working Cash Funds.