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Amazing Great Salt Lake

The effective area of the Great Salt Lake Basin is approximately 21,000 square miles. As mapped, its four major subbasins actually encompass 34,363 square miles, but the far West Desert Basin yields only small amounts of groundwater to the lake.

It’s salty. It’s stinky. It’s buggy. Many people think that the water that ends up in the lake has simply gone to waste. Actually, that couldn’t be further from the truth. Great Salt Lake supports a rich and dynamic biological system of regional, national, and global significance. The amazing abundance of bird life at Great Salt Lake has earned it the designation as a “Western Hemisphere Shorebird Reserve.” Each year over seven million birds from 257 different species rely on the lake during their thousand-mile or more migrations. Remote islands, shorelines, and about 400,000 acres of wetlands provide safe sancturary for migratory birds to feed, nest, and rest. These diverse water environments are connected to expansive playas and uplands that create excellent habitats for innumerable plants, invertebrates, reptiles, amphibians, mammals and birds.

Great Salt Lake sits at the bottom of a closed basin. It is a terminal lake with no outlet, so the only way water can leave is by evaporation. For the most part, what goes into the lake, stays in the lake. The vast majority of water flowing into the lake comes from the Bear, Weber and Jordan Rivers. This fresh water contains naturally occurring dissolved minerals and salts, which get left behind during evaporation. Over many thousands of years this has created a salty inland sea.

Of course, minerals and salts aren’t the only things that never leave the lake. Chronic levels of heavy metals, such as mercury, and excess nutrients from human activities are among the pollutants of concern. Our place in the Great Salt Lake Watershed means that Salt Lake County residents can help protect the health of the lake ecosystem.


A couple of birds fighting. A couple of birds fighting.

American Avocets

American avocets take flight in a cloud of brine flies. Photo ©U.S. Fish and Wildlife Service

Lake Facts

  • On average Great Salt Lake (GSL) covers 1,700 square miles, with a maximum depth of 33 feet and a surface elevation at 4,200 ft.
  • The Great Salt Lake Watershed is over 21,000 square miles. It is a “closed basin” where no water flows out. The lake is the lowest point in the landscape.
  • Fresh water enters Great Salt Lake via direct precipitation, three rivers (the Bear, Weber and Jordan River) and internal springs.
  • Water entering Great Salt Lake carries dissolved minerals.
  • Evaporation leaves the minerals and salts behind.
  • Salinity varies across the lake and is typically 3 to 5 times saltier than the ocean. The saltiest regions are almost 9 times saltier!
  • The notorious “lake stink” is most noticeable to residents of Salt Lake County when northwest winds blow across the lake and stir up shallow sediments. Decaying organic matter is the culprit, and is largely attributed to human-caused excess nutrients in Farmington Bay.
  • 75% of Utah’s wetlands are located in the Great Salt Lake Ecosystem.
  • The Great Salt Lake is an ecosystem of regional, national and global importance for migratory birds. Over 7 million migratory birds stop at the lake each year to feed, nest, and rest.
  • The lake is alive! Bacteria, algae, zooplankton, brine shrimp, and brine flies form an important food web.
  • The Union Pacific Railroad Causeway divides the lake into the North and South Arms with vastly different ecosystems on either side.
  • The North Arm of the lake is currently so salty that only two known types of bacteria can live there.
  • Brine shrimp harvest and mineral extraction industries are worth millions of dollars.
  • You probably eat Great Salt Lake every day! One of Morton Salts biggest plants is in Salt Lake City.
  • Great Salt Lake is popular for wildlife viewing, boating, swimming, and hiking. It attracts visitors from around the world.