All street grades shall be the grades at the top of the curb unless specifically established otherwise. The official elevations of the corners of intersecting streets, intersecting said street at points between points on which the official elevations are fixed by ordinance, shall be and are hereby fixed at an elevation being on a straight line connecting the two established points nearest said intersecting corners.

All street grades shall include grades at the top of the curb, and the grade at the vertex of the crown line of the paving or surfacing. [Code 1975 § 8-1.0603.]