(A) The datum line for the grades of streets, alleys, sewers, bridges, culverts and other similar improvements in the City is established at 135.63 feet below the top of the south end of the stone water table at the southeast corner of the Ashton block, located on Inlot No. 123 in the City.
(B) All grades or levels now or hereafter established shall be designated by giving the height in feet and hundredths of a foot above the datum line herein established.
(1956 Code Sec. 107.01)