Hydrology
The Utah Lake watershed drains 3,846 square miles (9,960 km2) over mostly mountainous terrain. The watershed's highest point is at 11,765-foot (3,586 m) Bald Mountain in the Uinta Mountains. 782,335 acres (3,166 km2) (32%) are managed by the United States Forest Service, 249,329 acres (1,009 km2) (11%) are managed by other government entities, and the majority of the rest, 1,263,696 acres (5,114 km2) (51%), are privately owned.
Two major tributaries account for nearly 60% of inflow by streams or rivers into Utah Lake. The Provo River accounts for 36% of the inflow, and the Spanish Fork River accounts for 24%. Other tributaries include the American Fork River, Current Creek, Dry Creek, Hobble Creek, and Mill Race Creek. Additionally, there are many hot springs and smaller creeks flowing into the lake. Utah Lake is drained by the Jordan River, which begins at the lake's north end. The river flows north through Utah, Salt Lake, and Davis counties and then into the southeast portion of the Great Salt Lake. Given the lake’s semi-arid climate, large surface area, and shallow average depth, evaporation accounts for 42% of Utah Lake's outflow.
After several years of drought, irrigation companies were arguing over their share of Utah Lake's water from the Jordan River. Judge Morse of the Third District Court issued his judgment that became known as the Morse Decree of 1901. The decree stated that the irrigation companies "are entitled to a decree awarding to them, subject to the limitations hereinafter set forth, the right to the use of all the balance of the waters of the Jordan River, for municipal, irrigation, culinary, and domestic purposes, to the extent of the capacity of their several canals, and the right to impound and store all of the waters of said river in Utah Lake." In response to the drought, a pumping plant was installed at the outlet of the Jordan River from Utah Lake. It was the largest pumping plant in the United States at the time. The plant contained seven pumps with a total capacity of 700 cubic feet (20 m3) per second. After the decree was released, Utah Lake essentially became an irrigation reservoir and the Jordan River's flow was highly regulated.
As a result of the 1983-1984 flooding, a lawsuit was filed for compensation due to flooding based upon breach of contract of the previous compromise level. In 1985, a new compromise level was reached which governed the maximum level of the lake. The new level was chosen to be 4,489 feet (1,368 m) above sea level. When the water level in Utah Lake exceeds this level, the Jordan River pumps and gates are left open. The new compromise level also meant that the lake's elevation was below Jordan River's stream bed.
Read more about this topic: Utah Lake