The siphon spillway shown below is 100 feet long with a 1.0-ft-diameter and conveys water to a downstream reservoir. The friction losses in the rough concrete siphon are distributed evenly throughout its length. If the siphon's summit (high point) is 7 feet above the surface of the upper reservoir and 18 feet (in pipe length) from the entrance, is cavitation (i.e., a pressure less than two thirds of atmospheric pressure or -9.8 lb/in?) a concern? 15 60ft