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Investigation of Great Salt Lake
Flood Protection Alternatives
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Studies and investigations to find alternatives to protect development around the Great Salt Lake did not start with the high levels of the 1980s. The Great Salt Lake has historically experienced wide cyclic fluctuation of its surface elevation, which has continually plagued those who have utilized its shores.

During the period from 1940-1965, when the lake was relatively low, it was thought by many that the lake would remain low or even dry up. Development around the lake during this period included large wildlife management areas at the mouths of the rivers, large evaporation ponds in low areas for the salt extraction industries, major roads and railroads across and along the shores, recreation facilities, and a causeway connecting the east shore to Antelope Island.

A peak elevation of 4202.3 feet was reached in 1976 that prompted a renewal of public awareness of the lake and problems associated with high levels of the lake. This public awareness provided new legislative support to state agencies and universities to address problems related to flooding problems around the lake.

Industries along the lake's shore at this time were experiencing a financial strain due to productivity losses and structural damage. Concern also existed for wildlife and recreational areas around the lake. In the three years following 1976, the lake level receded more than two feet (1977-78 was one of the lowest precipitation years on record). In September 1982, however, the lake began rising rapidly again due to abnormal high rainfall and an abrupt ending of the evaporating season. The continued high precipitation caused inflows of 7.5 million acre-feet in 1983 and 9.0 million acre-feet in 1984. This caused the lake to peak at elevation 4204.70 feet in June 1983 and at elevation 4209.25 feet in June 1984. The two successive rises of the lake (approximately five feet each) were the two largest rises of the lake in historical record.

Alternatives were proposed by the Division of Water Resources and many others were suggested by the public. Alternatives were grouped as follows:

  • Export flood flows from the Great Salt Lake drainage basin, mainly to the Bear River and Sevier River drainages.
  • Store water within the basin before it reaches the Great Salt Lake, mainly in reservoirs associated with the Bear River. Most of the reservoirs were part of ongoing studies on the Bear River to develop some of the Bear River flows.
  • Consume (through evapotranspiration) large amounts of water within the basin. This type of alternative would require large diversions to new agriculture lands. In some cases, water would be supplied from one of the reservoirs involving the Bear River. Only a couple of proposals matched this concept; one was the Utah Lake/Cedar Valley Pumping Project.
  • Continue letting the flood flow collect in the Great Salt Lake.

Many of the proposed alternatives dealt with flood flows and high lake level once the water was in the lake. These ideas included:

  • Breach the Southern Pacific Railroad Causeway to lower the south arm and raise the north arm,
  • Dike around the lake to protect major facilities and resources, close the Southern Pacific Causeway and divert the Bear River into the north arm to maintain the south arm lower than the north arm,
  • Build a pump/storage/power project in Puddle Valley,
  • Pump water from the lake to the West Desert (West Desert Pumping Project).

The Division of Water Resources published a report in January 1984 entitled, Great Salt Lake Summary of Technical Investigations for Water Level Control Alternatives that summarized alternatives associated with the Bear River, Utah Lake and the Great Salt Lake, except diking.

A major study, Great Salt Lake Diking Feasibility Study, was prepared in December 1984. In 1984-85, these ongoing investigations were summarized in the short report, Great Salt Lake Summary of Lake Control/Management Alternatives.

During 1983, and to a limited extent in 1984, the Division of Water Resources under special assignment from the Executive Director of the Department of Natural Resources conducted technical studies on several alternatives to supplement existing data and to assess the feasibility of the alternatives. The studies, undertaken by the division in 1983, were summarized in its report Great Salt Lake Summary of Technical Investigations Water Level Control Alternatives.

The ongoing work in 1984 relates mainly to directions given to the Division of Water Resources through Senate Bill 97. Engineering studies being conducted by the division included water quality studies on the Bear River; investigations related to the South Fork, Avon and Oneida Narrows Reservoirs on the Bear River; the Cedar Valley Project; work on the West Desert Pumping Alternative; and some in-house reconnaissance-level investigations of proposals to dam the north arm of the Great Salt Lake, dam the Bear River Bay, and selective diking along the east shore of the lake.

In general, the analysis of these alternatives, together with economic and political aspects, led to the following considerations

  1. Export flood flows from the Great Salt Lake Drainage Basin - Diversion to Portneuf River was evaluated, but costs were three to four times more than West Desert pumping with only a third of the effect on the lake. Many other concerns were raised in any proposal to add flood flows to streams outside the basin which may also be at peak flows.
  2. Store water within the basin - Investigations showed that these alternatives (when analyzed as a Great Salt Lake flood alternative) required five-plus years to construct, would have very small impact on the level of the lake, and were more expensive than West Desert pumping.
  3. Evapotranspiration of new amounts of water within the basin - These alternatives were included in the Utah Lake/Cedar-Rush Valley Project. They also were medium to high time for construction, costly compared to West Desert pumping, and would have very small effect on the level of the Great Salt Lake. Further, it was uncertain if such a project would have a water supply during average water years.

Eventually, the evaluation of alternatives led to the recommendation that West Desert pumping was the alternative that could be constructed in a short period (less than two years), would have a major impact on the level of the Great Salt Lake, and would have the best benefit-to-cost comparison.

Results of these collective investigations led to an overall concept for dealing with the flooding Great Salt Lake.

  1. Allow/use the natural terminal point of the lake to store flood flows and find ways to remove them once captured in the lake.
  2. Breach the causeway to reduce the head difference between the north and south arms of the Great Salt Lake. This, in effect, would lower the south arm where much of the flood damages occurred.
  3. Build the West Desert Pumping Project to remove water from the lake through evaporation. The project would evaporate up to 800,000 acre-feet of additional water from the Great Salt Lake.
  4. Build certain dikes to protect infrastructure around the lake. These included dikes around major sewage treatment plants. Raise parts of roads around the shore areas of the lake, including areas of I-80 and I-15. Also raise major causeways/dikes within the lake, including the railroad causeway.

References:
Anderson, D. Larry, Great Salt Lake Flooding, paper presented to the Interstate Conference on Water Problems (ICWP) at Big Sky, Montana, Utah Division of Water Resources, Salt Lake City, Utah, August 1985
  Arnow, Ted, Water Level and Water Quality Changes in Great Salt Lake, 1847-1983, Circular 913, U. S. Geological Survey, Salt Lake City, Utah, 1983.
  Austin, Lloyd H., Lake Level Predictions of the Great Salt Lake, paper in Great Salt Lake - A Scientific, Historical and Economic Overview, edited by J. Wallace Gwynn, Ph.D., Utah Department of Natural Resources, Division of Geological Survey, Salt Lake City, Utah, 1980.
  Utah Department of Natural Resources, Recommendations for a Great Salt Lake Contingency Plan - For Influencing High and Low Levels of Great Salt Lake, Salt Lake City, Utah, 1983.