Topographic maps with contour intervals of two (2) feet (or less) and details of existing drainage structures and watercourses shall be submitted along with calculations for all watersheds affecting areas of the purposed storm drain design. Drainage design shall be computed as noted in the drainage section of this ordinance. Maps showing the delineation and flow from each drainage area must be included in the plans along with all hydraulic calculations. Street and drainage profiles shall show the location of the hydraulic grade line.