Provision shall be made in the annual budget and in the appropriation ordinance for a contingent appropriation in an amount not more than five (5) per cent of the total general fund expenditures, to be used in case of unforeseen items of expenditures. Such contingent appropriation shall be under the control of the City Manager and distributed by him only after prior approval by the City Council. The proceeds of the contingent appropriation shall be disbursed only by transfer to other departmental appropriation, the spending of which shall be charged to the departments or activities for which the appropriations are made.