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Research about Idaho;Montana;Nevada;Utah;Wyoming

Source-linked reports with geographic coverage including Idaho;Montana;Nevada;Utah;Wyoming.

3 recordsLinked to original sources

USGS1996

Major sources of nitrogen input and loss in the upper Snake River basin, Idaho and western Wyoming, 1990

Total nitrogen input and loss from cattle manure, fertilizer, legume crops, precipitation, and domestic septic systems in the upper Snake River Basin, Idaho and western Wyoming, were estimated by county for water year 1990. The purpose of these estimations was to rank input of nitrogen by source, determine the amount of total nitrogen potentially available to both ground and surface water through leaching and runoff, and identify areas in the basin where excess nitrogen is produced. The results of the input estimations suggest that domestic septic systems account for less than 1 percent of the total nitrogen input in the basin and precipitation accounts for 6 percent. The remaining 93 percent is produced by cattle manure (29 percent), fertilizer (45 percent), and legume crops (19 percent). Input from cattle manure, fertilizer, and legume crops varies widely among counties and reflects differences in land-use practices such as different cropping patterns and numbers of dairies and feedlots. Residual total nitrogen was estimated by subtracting loss due to cattle manure storage and application, crop uptake, and decomposition of previous-year nonleguminous crop residue (chaff) from all nitrogen input in the basin. Positive mean values of residual total nitrogen in most counties suggest that more total nitrogen is input than is lost. This residual total nitrogen is available for runoff to surface water or leaching to ground water. Three out of four counties where mean values of residual total nitrogen were highest (Cassia, Gooding, and Twin Falls) are located in the western part of the basin, where eutrophication in the Snake River is evident and ground water from many wells contains anomalously high nitrate concentrations. Ground water in the fourth county (Bingham), which includes the Fort Hall area north of Pocatello, also contains high nitrate concentrations. A mass balance of total nitrogen input and loss in Gooding, Jerome, Lincoln, and Twin Falls Counties suggests that more than 6,000,000 kg (6,600 tons) of total nitrogen is input in this four-county area than is discharged by the Snake River. This excess nitrogen probably is utilized by aquatic vegetation in the Snake River (causing eutrophication), stored as nitrogen in soil, stored as nitrate in the ground water and eventually discharged through the springs, utilized by noncrop vegetation, and lost through denitrification.

Idaho;Montana;Nevada;Utah;Wyoming↗

USGS1994

Assessment of selected constituents in surface water of the upper Snake River basin, Idaho and western Wyoming, water years 1975-89

In 1991, a water-quality investigation of the upper Snake River Basin was initiated as part of the U.S. Geological Survey's National Water-Quality Assessment Program. The initial task of the assessment was to compile and analyze available nutrient, suspended sediment, and pesticide data collected in the basin. For analysis of nutrients and suspended sediment, data collected during water years 1980-89 were used. For pesticides, an additional 5 years of data were included for a total assessment period encompassing water years 1975-89. Nearly 9,000 analyses of nutrients and suspended sediment from more than 450 stations were retrieved from the U.S. Environmental Protection Agency STORET and U.S. Geological Survey WATSTORE data bases. Nineteen stations had sufficient analyses for quantitative assessment. Of the 19 stations analyzed, 4 are located on relatively unaffected stream reaches, 8 are at or near mouths of tributary basins affected by agricultural activities, and 7 are on the main stem of the Snake River. Data indicate that nitrite plus nitrate and total phosphorus concentrations generally increased in a downstream direction along the Snake River; concentrations were largest at the mouths of drainage basins tributary to the Snake River. Water-quality stations were categorized as unaffected or minimally affected, agriculturally affected, or main stem to compare nutrient concentrations between drainage basins of differing land use/land cover. Concentrations of nitrite plus nitrate, total nitrogen, dissolved orthophosphate, and total phosphorus were significantly (p<0.05) larger at agriculturally affected and main-stem stations than at unaffected stations; and concentrations of nitrite plus nitrate, total nitrogen, and total phosphorus at agriculturally affected stations were significantly larger than at main-stem stations. Significant differences in seasonal concentrations of some nutrient species also were noted. Few suspended sediment and pesticide data were available for the study basin. Only six stations had sufficient data for quantitative assessment of suspended sediment. A direct positive relation exists between suspended sediment concentration and streamflow; concentrations are largest in April, May, and June at high streamflow. Most of the pesticide data compiled from STORET and WATSTORE were collected during water years 1975-79. Only 33 pesticide samples, excluding samples collected for a Rural Clean Water Program, were collected from surface water and bottom sediment during water years 1980-89. Bottom sediment collected near the mouth of the Henrys Fork during the late 1970's had the largest concentrations of pesticides in the basin; DOT, ODD, and DDE concentrations exceeded 10 micrograms per kilogram. Mass movement of nutrients and suspended sediment in the upper Snake River Basin is controlled primarily by changes in streamflow. Between two and three times as much total nitrogen, total phosphorus, and suspended sediment were transported out of the basin in water year 1984 (high-flow year) compared with 1989 (low-flow year). Reservoirs on the main stem of the Snake River probably trap much of the nutrient and most of the suspended sediment load generated from upper parts of the basin. A more extensive data-collection program in the upper Snake River Basin is needed to address a number of water-quality issues. These include an analysis of effects of land use on the quality of surface water; quantification of mass movement of nutrients and suspended sediment at key locations in the basin; distribution of aquatic organisms; and temporal and spatial distribution of pesticides in surface water, bottom sediment, and biota.

Idaho;Montana;Nevada;Utah;Wyoming↗

USGS1994

Analysis of data on nutrients and organic compounds in ground water in the upper Snake River basin, Idaho and western Wyoming, 1980-91

Nutrient and organic compound data from the U.S. Geological Survey and the U.S. Environmental Protection Agency STORET data bases provided information for development of a preliminary conceptual model of spatial and temporal ground-water quality in the upper Snake River Basin. Nitrite plus nitrate (as nitrogen; hereafter referred to as nitrate) concentrations exceeded the Federal drinking-water regulation of 10 milligrams per liter in three areas in Idaho" the Idaho National Engineering Laboratory, the area north of Pocatello (Fort Hall area), and the area surrounding Burley. Water from many wells in the Twin Falls area also contained elevated (greater than two milligrams per liter) nitrate concentrations. Water from domestic wells contained the highest median nitrate concentrations; water from industrial and public supply wells contained the lowest. Nitrate concentrations decreased with increasing well depth, increasing depth to water (unsaturated thickness), and increasing depth below water table (saturated thickness). Kjeldahl nitrogen concentrations decreased with increasing well depth and depth below water table. The relation between kjeldahl nitrogen concentrations and depth to water was poor. Nitrate and total phosphorus concentrations in water from wells were correlated among three hydrogeomorphic regions in the upper Snake River Basin, Concentrations of nitrate were statistically higher in the eastern Snake River Plain and local aquifers than in the tributary valleys. There was no statistical difference in total phosphorus concentrations among the three hydrogeomorphic regions. Nitrate and total phosphorus concentrations were correlated with land-use classifications developed using the Geographic Information Retrieval and Analysis System. Concentrations of nitrate were statistically higher in area of agricultural land than in areas of rangeland. There was no statistical difference in concentrations between rangeland and urban land and between urban land and agricultural land. There was no statistical difference in total phosphorus concentrations among any of the land-use classifications. Nitrate and total phosphorus concentrations also were correlated with land-use classifications developed by the Idaho Department of Water Resources for the Idaho part of the upper Snake River Basin. Nitrate concentrations were statistically higher in areas of irrigated agriculture than in areas of dryland agriculture and rangeland. There was no statistical difference in total phosphorus concentrations among any of the Idaho Department of Water Resources land-use classifications. Data were sufficient to assess long-term trends of nitrate concentrations in water from only eight wells: four wells north of Burley and four wells northwest of Pocatello. The trend in nitrate concentrations in water from all wells in upward. The following organic compounds were detected in ground water in the upper Snake River Basin: cyanazine, 2,4-D DDT, dacthal, diazinon, dichloropropane, dieldrin, malathion, and metribuzin. Of 211 wells sampled for organic compounds, water from 17 contained detectable concentrations.

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