(a) Payments and Obligations Prohibited. No payment shall be made or obligation incurred against any allotment or appropriation except in accordance with appropriations duly made, and unless the City Treasurer or designee first certifies that there is a sufficient unencumbered balance in such allotment or appropriation and that sufficient funds therefrom are or will be available to cover the claim or meet the obligation when it becomes due and payable. However, nothing in this Charter shall be construed to prevent the making or authorizing of payments or making of contracts for capital improvements to be financed wholly or partly by the issuance of bonds or to prevent the making of any contract or lease providing for payments beyond the end of the fiscal year, provided that such action is made or approved by ordinance.