Great Salt Lake is located on a shallow playa. Consequently, small changes in the water-surface elevation result in large changes in the surface area of the lake. This is particularly evident when the lake spills into the west desert at an elevation of about 4215 feet, greatly increasing its area. The satellite imagery shows changes in the area of the lake from 1972, through the high-runoff period of 1983-87, and ending in 1996. At the historic average (1847-1986) surface elevation of 4,200 feet (1975 is an "average year" shown in the images), the lake covers an area of about 1,700 square miles. At the historic low elevation of 4,191.35 in 1963, the lake covered only 950 square miles. The drop of about 8.5 feet in elevation resulted in a loss of about 44 percent in surface area. During 1986 and again in 1987, the lake reached an elevation of 4,211.6 feet and had a surface area of about 3,300 square miles. The relation between water-surface elevation and corresponding surface area and volume of the lake is shown on an elevation-area-volume curve, also called a hypsographic curve (from the Greek, hypsos, meaning height).
The U.S. Geological Survey (USGS) has measured the elevation of Great Salt Lake since 1875 and conducted many studies on the hydrology, salinity, water quality, and ecology of the lake. Currently, the USGS operates lake elevation gages at Saltair Marina, Saline (north arm), and on the railroad causeway near Promontory Point. The USGS is studying the ecology of brine shrimp in the lake in cooperation with the Utah Division of Wildlife Resources (requires Frames compatible browser) and researchers from the Department of Fisheries and Wildlife at Utah State University.
In addition to measuring changes in lake elevation, since the early 1960s the USGS has conducted detailed studies of the physical and chemical hydrology of the lake. These have included investigations of the prehistory of the lake, general hydrology of closed-basin lakes, effects of human activities on the lake, and a detailed accounting of the water budget.
The salts of the lake are primarily sodium chloride (common salt), although small amounts of other elements and salts are also present, including magnesium, potassium, sulfate, and carbonate. There are about 4.5 to 4.9 billion tons of salt in the lake, and about 2.2 million tons of salt enter the lake annually from surface- and ground-water flow. The salt industries extract about 2.5 million tons of sodium chloride and other salts and elements from the lake annually.
Brine shrimp are not only the most visible inhabitants of Great Salt Lake and are very important to the ecology of the lake, serveing as a major source of food for migratory birds. They are also valuable for the hard-walled eggs they produce, which are commercially harvested and used worldwide in the aquaculture industry.
Great Salt Lake supports between 2 and 5 million shorebirds, as many as 1.7 million eared grebes, and hundreds of thousands of waterfowl during spring and fall migration. Because of its importance to migratory birds, the lake was designated a part of the Western Hemisphere Shorebird Reserve Network in 1992. The lake and its marshes provide a resting and staging area for the birds, as well as an abundance of brine shrimp and brine flies that serve as food.
The planktonic habitat in Great Salt Lake consists of the open water inhabited by brine shrimp, phytoplankton (algae), bacteria, and other small zooplankton. These organisms are all free-swimming or float in the water. The benthic habitat consists of the bottom substrate of the lake and its associated organisms. These organisms are primarily brine-fly larvae and benthic algae.
This is a brief explanation and listing of boating and recreation on Great Salt Lake.
The mission of Friends of Great Salt Lake is to increase public awareness and appreciation of the lake through education, research, and advocacy.
The Utah Wetlands and Riparian center
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U.S. Department of the
Interior || U.S. Geological
Survey 2329 Orton Circle, West Valley City, UT 84119, USA URL: http://ut.water.usgs.gov/greatsaltlake/index.html Maintainer: jfgardne@usgs.gov Last modification: 03-May-2001 Privacy Statement || Disclaimer |