The Board shall authorize the granting of all pensions and other benefits payable from funds of the retirement system; determine the amount of service to be credited each member within the provisions of the ordinance not inconsistent with the provisions of this chapter; keep proceedings of its meetings; cause necessary data to be kept for the proper operation of the retirement system; adopt from time to time mortality and other tables of experience, and a rate or rates of interest necessary for the operation of the retirement system on an actuarial basis; employ such professional and clerical services as are required; and to adopt such rules and regulations, not inconsistent with the provisions of this chapter and the operation ordinance, as are necessary in the operation of the retirement system.