An average of about 2.9 million acre feet of water evaporates from the Great Salt Lake annually.
Annual Evaporation Rate
Water loss from the Great Salt Lake occurs primarily through evaporation. Based on historical data, the average amount of water that evaporates from the lake each year is approximately 2.9 million acre feet.
Understanding "Acre-Feet"
An acre-foot is a standard unit used in water management to measure large volumes. It represents the volume of water needed to cover one acre of land to a depth of one foot. To put this into perspective, 2.9 million acre feet is a vast quantity, highlighting the significant impact of evaporation on the lake's water level and volume.
Why Evaporation is the Primary Water Loss
As referenced, water is lost from the Great Salt Lake mostly through evaporation. Unlike freshwater lakes that might have significant outflows via rivers, the Great Salt Lake is an endorheic basin – it has no outlet to the ocean. Water flows into the lake, but leaves primarily through evaporation. This makes evaporation the dominant process determining the lake's size and salinity.
Seasonal Variation in Evaporation
Evaporation rates are not constant throughout the year. They are highest during the hot summer months when temperatures are high and sunlight is intense. Conversely, evaporation rates are lowest during the colder winter months.
Here's a simple overview of the seasonal variation:
| Season | Evaporation Rate |
|---|---|
| Summer | Highest |
| Winter | Lowest |
This seasonal cycle of evaporation plays a significant role in the natural fluctuations of the lake's level throughout the year, in addition to inflow from rivers and precipitation.
