Gene Yang ‘19

Representing nearly half of the volume and a quarter of the area of all lakes in the world, saline lakes are a significant part of the regional ecosystem. However, as a result of human consumptive water use from these lakes in recent decades, many large saline lakes have been desiccating at a significant rate. This dessication can eventually lead to the collapse of local waterbird habitats. In order to estimate the water inflow needed to sustain these habitats, researchers from Utah State University documented the decrease in water volume amongst other variables in Utah’s Great Salt Lake over the past decades.

Data including mean river flow, human water consumption, and mean lake elevations was collected and compared. The mean river flow data was retrieved from two tributaries connected to the lake: Blacksmith Fork and Bear River. The composite regression line conveyed a slightly upwards trend in flow, but no signifiant change (p = 0.085). On the other hand, mean lake elevations displayed a significant decline over the past century at a decrease of 3.6 meters and 46% volume (p < 0.0001), primarily as a result of human water consumption.

Recent river inflow data per year for three lakes—the Great Salt Lake, Lake Urmia, and Walker Lake—were then gathered in order to determine the mean sustained increase in flow needed to revert these lakes to fully functioning ecosystems. Target lake recovery elevations were based on pre-water consumption elevation levels, as well as present day salt-corrected evaporation rates. It was determined that a 29%, 83%, and 24% increase in river flow (km3/yr) are needed to maintain such levels for the Great Salt Lake, Lake Urmia, and Walker Lake, respectively. While consumptive use of water from these lakes for agricultural irrigation and industrial purposes is crucial, saline lake preservation is also necessary in order to ensure the long term sustainability of this water source.

References

1. W.A. Wurtsbaugh, et al., Decline of the world’s saline lakes. Nature Geoscience 10, 737-740 (2017). doi: 10.1038/ngeo3052
2. Image retrieved from: https://upload.wikimedia.org/wikipedia/commons/2/23/Lake_mapourika_NZ.jpeg