At the same time that he or she submits the general fund budget, the mayor shall submit to the council a capital improvement program covering all recommended capital improvement projects, for the ensuing fiscal year and for the four fiscal years thereafter, with his or her recommendations as to the means of financing the improvements proposed for the ensuing fiscal year. The council shall have power to accept with or without amendments or reject the proposed program and proposed means of financing for the ensuing fiscal year; and may from time to time during the fiscal year amend by ordinance adopted by at least five affirmative votes, the program previously adopted by it, or the means of financing the whole or any part thereof or both, provided that the amendment shall have been recommended by the mayor, and further, provided such additional funds are available in the general fund or in any other fund of the city available therefor. The council shall adopt a capital budget prior to the beginning of the fiscal year in which the budget is to take effect. No appropriations for a capital improvement project contained in the capital budget shall lapse until the purpose for which the appropriation was made shall have been accomplished or abandoned, provided that any project shall be deemed to have been abandoned if three fiscal years lapse without any expenditure from or encumbrance of the appropriation therefor. Any such lapsed appropriation shall be applied to the payment of any indebtedness incurred in financing the project concerned and if there be no such indebtedness shall be available for appropriation.