Pipe Slope from Invert Elevations

Equation: pipe slope S = drop in invert elevation / horizontal distance. Values: the invert drops from 102.50 ft at station 10+00 to 101.50 ft at station 12+00, so the drop is 102.50 − 101.50 = 1.00 ft. In U.S. stationing one full station is 100 ft, so 12+00 − 10+00 = 1200 − 1000 = 200 ft. Step 1: S = 1.00 / 200 = 0.005. Step 2: as a percent, 0.005 × 100 = 0.5%. Taking the run as 100 ft gives 1.0%, and slipping the decimal when converting to a percent gives 0.05% or 5%.