Provision shall be made in the annual budget for a contingent appropriation in an amount not to exceed ten percent (10%) of the total budget, to be used in case of unforeseen items of expenditure. Such contingent appropriation shall be under the control of, and distributed by, the City Manager, after approval by the City Council. Expenditures from this appropriation shall be made only in the event of established emergencies or public necessities, and a detailed account of such expenditures shall be recorded and reported.