Panguitch Lake TMDL
Panguitch Lake is located in the high mountains of southwestern Utah, at an elevation of 8,200 feet. It is a natural lake, but in 1885 a dam was built to increase the water capacity. When the lake is full, it is about 57 feet deep, covers approximately 1,234 surface acres and holds about 40,100 acre-feet of water. Panguitch Lake has 5 major tributaries, which are all creeks. Panguitch Lake has 5 beneficial use classifications, which include, 3A, 2B, 3C, 3D and 4. The only classification that is impaired is 3A. Class 3A is the protection of cold-water fish and other aquatic life. There are two causes for this impairment. The first cause is the amount of phosphorus in the water. The second cause is the low amount …show more content…
The average concentration of phosphorus exceeds the .025 mg/L parameter for class 3A waters. It is estimated that about 2,822 kilograms of phosphorus flow into Panguitch Lake each year from the surrounding tributaries.
There are currently no point sources located on the Panguitch Lake watershed. Studies were conducted to find indications of non-point sources contributing to the large phosphorus concentrations. Soil samples taken from the upper watershed areas showed a very large amount of natural occurring phosphorus along stream banks. The erosion of these soils into the adjacent tributaries is thought to be the leading cause of high phosphorus levels in Panguitch Lake. Other non-point sources found were home building and cattle grazing.
In order to meet the criteria for Class 3A, plans have been made to reduce phosphorus amounts by 1,767 kilograms per year. In order to meet this reduction two options have been proposed. The first option is to treat the lake with the chemical, aluminum sulfate. This chemical binds with the phosphorus to create precipitates that will sink to the bottom of the lake. Once at the bottom of the lake the precipitates react with sediment, which neutralizes the