Rocky Ford v. Kents Lake, 2019 UT 31 (July 11, 2019)

Rocky Ford is a downstream user of water rights from the Bear River.  Kents Lake is an upstream user.  The two entities had entered into various agreements over several decades.  With the advent of sprinkler irrigation, as compared to traditional irrigation, Kents Lake was using less of its upstream flow rights and therefore could store more of its water shares in a reservoir, which deprived Rocky Ford of downstream flow.  The supreme court held that Kents Lake was entitled to use its water in the most efficient manner within the bounds of its rights, and that downstream users, even with senior water rights, only have a right to water run-off to the extent it returns to the source; upstream users can benefit from efficiency gains and capture their own seepage.