Current modeling indicates the project will save 30 billion gallons of water by reducing the lake’s surface area, which in turn reduces evaporation and by removing invasive plants (primarily Phragmites).
Warm temperatures, shallow depths, and the large surface area of Utah Lake all contribute to evaporation. Utah Lake currently loses about 44% of its total volume annually (122 billion gallons or 375,000 acre-feet) to evaporation. The project will reduce water lost to evaporation by deepening the lake and reducing its surface area. Dredged sediment will be stored in containment areas, which will look like natural islands. These areas reduce the surface area of the lake by about 20%, creating a ~20% reduction in evaporation. Our current modeling show that as much as 24 billion gallons of water will be saved by evaporation reduction alone. The project will also remove 8,000+ acres of invasive Phragmites, also known as common reed, along the lake shore, which use much greater amounts of water than native lake shore plants. Replacing Phragmites with native water conscious species will help save approximately seven billion gallons of water each year. This combined is just over 31 billion gallons. It’s important to note these are preliminary estimates and the final project design could add to or decrease the savings, but it’s safe to say that billions of gallons of water will be added to the state’s water supply. Utah is the second-driest state in the nation, and 20 years into a megadrought. We could desperately use more water.