(Amended by Ordinance No. 182760, effective June 5, 2009.) All grade elevations in the City shall be referred to a fixed datum established herein. The datum plane for grades was originally established 56.743 feet below the initial bench mark set by the City in the southerly quadrant of the top step of the Soldiers’ Monument located in Lownsdale Square in the City, said bench mark being marked “CITY OF PORTLAND, INITIAL CLASS A BENCH MARK NO. 00, $50 FINE FOR DISTURBING.” A datum plane above described is hereby established as the official datum of the City. The United States geological survey bench mark set in the granite base of the north pillar of the porte cochere at the SW 5th Avenue central entrance to the City Hall in Portland has an elevation 78.835 feet above the datum plane of the City as herein established.