The upper Lehigh was a turbulent river with steep sides; a large portion was in a ravine, the Lehigh Gorge. The upper canal rose over in elevation to the Mauch Chunk slack-water pool. Unlike the lower canal (where most locks lifted less than in easy stages, the upper-canal design relied on deep-lift locks. The maximum lift on the lower canal was less than , but the upper-canal locks lifted a maximum of ; this is comparable to the lift of the lower canal in a bit over half the distance, using less than as many locks per mile. The upper canal design's 20 dams, 29 locks and a number of reservoirs provided working flow even in dry summers.