Research about Idaho,Utah, Wyoming

USGS2003

Water quality at fixed sites in the Great Salt Lake basins, Utah, Idaho, and Wyoming, water years 1999-2000

The Great Salt Lake Basins (GRSL) study unit of the National Water-Quality Assessment program encompasses the Bear River, Weber River, and Utah Lake/Jordan River systems, all of which discharge to Great Salt Lake in Utah. Data were collected during each month at 10 sites in the GRSL study unit from October 1998 to September 2000 to define spatial and temporal distribution and variability in concentration of nutrients, major ions, trace elements, suspended sediments, and organic compounds. Water samples collected from rangeland and forest sites in the GRSL study unit generally contained low concentrations of dissolved solids. Median dissolved-solids concentration in water samples was highest at sites with mixed land uses. Dissolved-solids concentration in some parts of the Bear River during low flow exceeded Utah State standards for agricultural use. Total-nitrogen concentration in water samples from GRSL sites ranged from 0.06 to 11 milligrams per liter. Water samples from predominantly forest and rangeland sites generally had a low total-nitrogen concentration. Many samples from sites with a higher percentage of agricultural and urban land cover had higher concentrations of total nitrogen. Fifty percent of the samples collected at GRSL sites had total phosphorus concentrations that exceeded 0.1 milligram per liter, the recommended limit for the prevention of nuisance aquatic-plant growth in streams not discharging directly into lakes or impoundments. Concentration of most trace elements in water samples from the fixed sites generally was low; however, arsenic concentrations, as high as 284 micrograms per liter, sometimes exceeded aquatic-life guidelines. Forty-three pesticides and 35 volatile organic compounds were detected in water samples from three GRSL sites; however, the concentration of most was low, less than 1 microgram per liter. The herbicides atrazine and prometon and the insecticides carbaryl and diazinon were the most frequently detected pesticides. Chloroform and toluene were detected in more than 90 percent of the samples and were the most frequently detected volatile organic compounds. The concentration of carbaryl, diazinon, malathion, and toluene in water samples from GRSL sites sometimes exceeded aquatic-life guidelines.

Idaho,Utah, Wyoming↗

USGS2000

Analysis of nitrate and volatile organic compound data for ground water in the Great Salt Lake Basins, Utah, Idaho, and Wyoming, 1980-98

In 1995, ground water was the source of drinking water to about 52 percent of the population served by public drinking water systems in the Great Salt Lake Basins study unit, which includes parts of Utah, Idaho, and Wyoming. Existing nitrate and volatile organic compound data for ground water collected in the study unit were compiled and summarized as part of the National Water-Quality Assessment Program’s objective to describe water-quality conditions in the Nation’s aquifers. Prerequisites for the inclusion of nitrate and volatile organic compound data into this retrospective analysis are that the data set is available in electronic form, the data were collected during 1980-98, the data set is somewhat regional in coverage, and the locations of the sampled sites are known. Ground-water data stored in the U.S. Geological Survey’s National Water Information System and the Idaho and Utah Public Drinking Water Systems databases were reviewed. Only the most recent analysis was included in the data sets if more than one analysis was available for a site. The National Water Information System data set contained nitrate analyses for water from 480 wells. The median concentration of nitrate was 1.30 milligrams per liter for the 388 values above minimum reporting limits. The maximum contaminant level for nitrate as established by the U.S. Environmental Protection Agency was exceeded in water from 10 of the 200 wells less than or equal to 150 feet deep and in water from 3 of 280 wells greater than 150 feet deep. The Public Drinking Water Systems data set contained nitrate analyses for water from 587 wells. The median concentration of nitrate was 1.12 milligrams per liter for the 548 values above minimum reporting limits. The maximum contaminant level for nitrate was exceeded at 1 site and 22 sites had concentrations equal to or greater than 5 milligrams per liter. The types of land use surrounding a well and the well depth were related to measured nitrate concentrations in the sampled ground water. Overall, water sampled from wells in rangeland areas had a lower median measured nitrate concentration (0.76 milligrams per liter) than water from areas with an agricultural or urban/residential land use (1.41 and 1.20 milligrams per liter, respectively). In the National Water Information System data set, the median measured nitrate concentration in water from urban/residential areas varied from 1.00 milligrams per liter for wells greater than 150 feet deep to 1.84 milligrams per liter for wells less than or equal to 150 feet deep. The Public Drinking Water Systems and the National Water Information System data sets contained analyses for most of the State and Federally regulated volatile organic compounds in water from about 368 and 74 wells, respectively. Fifteen different volatile organic compounds were detected at least once in ground water sampled from the Great Salt Lake Basins study unit. Water from 21 wells contained at least 1 volatile organic compound at detectable concentrations. About 68 percent of the volatile organic compounds detected were in water sampled from wells in Salt Lake County, Utah. Tetrachloroethylene was the most commonly detected volatile organic compound in ground water sampled from the study unit, present in 8 out of 442 samples. Maximum contaminant levels for tetrachloroethylene and 1,1-dichloroethylene as established by the U.S. Environmental Protection Agency were exceeded in water from one well each.

Idaho,Utah, Wyoming↗