Utah Lake levels, 1992–2015

 

Utah Lake has been the subject of much recent study, including a special series on WWR. Here, we examine its historic water-level fluctuations over the last 24 years.

Utah Lake’s depth varies for many reasons, including climate, flood control, and water rights, just to name a few. Water level is measured relative to the “Compromise Elevation”: the legal level, established by agreement in 1985, at which the lake is considered full.

Data were obtained from the Central Utah Water Conservancy District and the Utah Water Ski Club, with monthly readings on the 1st of each month.* The average lake level from 1992 to 2015 was 2.0 feet below compromise.

Figure 1 shows a time series of monthly water-level observations at Utah Lake. Levels vary by several feet throughout the year, which, in a lake that is already famously shallow, can be quite noticeable, especially for boaters. Longer multi-year cycles are also visible, including the two seen here, lasting about 10 years each. The recent trend has been that of declining water levels due to a few consecutive years of below-average snowpack since 2011. This year, the average level has been about

utah_lake_1

Figure 2 shows the same data, this time overlapped to facilitate comparisons among years. Average annual fluctuation during this period was 2.1 feet. In general, water levels peak in June or July, following spring runoff, and are lowest in October.

utah_lake_2

* One data point, December 2012, appeared to have an incorrect sign (+2.6 instead of -2.6) and was corrected.

 

Robert B. Sowby

Robert B. Sowby is a water resources engineer at Hansen, Allen & Luce. A graduate of BYU, MIT, and the U, he has contributed to over 100 civil, water, and environmental projects throughout North America.

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