Geology topics

Research about Idaho;Wyoming

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

6 recordsLinked to original sources

USGS2000

Global ice-core research: Understanding and applying environmental records of the past

One way to study Earth’s past environmental conditions is to look at ice cores recovered from glaciers. Every year a layer of snow accumulates on glaciers, like a page in a history book, and eventually turns to ice. Like reading the pages of a history book, analyzing the layers in a glacial ice core for specific chemical and physical components is a way of “reading” the environmental changes of the past. Information from ice cores collected from Greenland and Antarctica already has provided important historical clues toward a better understanding of modern global environmental changes (Dansgaard and Oeschger, 1989; Lorius and others, 1989). Environmental changes are of major concern at low- or mid-latitude regions of our Earth simply because this is where 80 to 90 percent of the world’s human population live. Ice cores collected from isolated polar regions are, at best, proxy indicators of low- and mid-latitude environmental changes. Because polar icecore research is limiting in this sense, ice cores from low- and mid-latitude glaciers are being used to study past environmental changes in order to better understand and predict future environmental changes that may affect the populated regions of the world.

Idaho;Wyoming↗

USGS1998

Water quality in the upper Snake River basin, Idaho and Wyoming, 1992-95

This report is intended to summarize major findings that emerged between 1992 and 1995 from the water-quality assessment of the Upper Snake River Basin Study Unit and to relate these findings to water-quality issues of regional and national concern. This information is primarily intended for those who are involved in water-resource management. Yet, the information contained here may also interest those who simply wish to know more about the quality of water in the rivers and aquifers in the area where they live.

Idaho;Wyoming↗

USGS1997

Assessment of nutrients, suspended sediment, and pesticides in surface water of the upper Snake River basin, Idaho and western Wyoming, water years 1991-95

A water-quality investigation of the upper Snake River Basin began in 1991 as part of the U.S. Geological Survey's National Water- Quality Assessment Program. As part of the investigation, intensive monitoring was conducted during water years 1993 through 1995 to assess surface-water quality in the basin. Sampling and analysis focused on nutrients, suspended sediments, and pesticides because of nationwide interest in these constituents. Concentrations of nutrients and suspended sediment in water samples from 19 sites in the upper Snake River Basin, including nine on the main stem, were assessed. In general, concentrations of nutrients and suspended sediment were smaller in water from the 11 sites upstream from American Falls Reservoir than in water from the 8 sites downstream from the reservoir where effects from land-use activities are most pronounced. Median concentrations of dissolved nitrite plus nitrate as nitrogen at the 19 sites ranged from less than 0.05 to 1.60 milligrams per liter; total phosphorus as phosphorus, less than 0.01 to 0.11 milligrams per liter; and suspended sediment, 4 to 72 milligrams per liter. Concentrations of nutrients and suspended sediment in the main stem of the Snake River, in general, increased downstream. The largest concentrations in the main stem were in the middle reach of the Snake River between Milner Dam and the outlet of the upper Snake River Basin at King Hill. Significant differences (p<0.05) in nutrient and suspended sediment concentrations were noted among groups of sites categorized by the quantity of agricultural land in their upstream drainage basins. Water samples collected from sites in drainage basins where agricultural land constituted less than 10 percent of the land use contained significantly smaller concentrations of nutrients and suspended sediment than samples from sites in drainage basins where agricultural land constituted more than 10 percent of the land use. Significant differences in nutrient and suspended sediment concentrations were inconsistent among groups representing 10 to 19 percent, 20 to 29 percent, and greater than 29 percent agricultural land use. Seasonal concentrations of dissolved nitrite plus nitrate, total phosphorus, and suspended sediment were significantly different among most of the agricultural land-use groups. Concentrations of dissolved nitrite plus nitrate were largest during the nonirrigation season, October through March. Concentrations of total phosphorus and suspended sediment, in general, were largest during high streamflow, April through June. Nutrient and suspended sediment inputs to the middle Snake reach were from a variety of sources. During water year 1995, springs were the primary source of water and total nitrogen to the river and accounted for 66 and 60 percent of the total input, respectively. Isotope and water-table information indicated that the springs derived most of their nitrogen from agricultural activities along the margins of the Snake River. Aquacultural effluent was a major source of ammonia (82 percent), organic nitrogen (30 percent), and total phosphorus (35 percent). Tributary streams were a major source of organic nitrogen (28 percent) and suspended sediment (58 percent). In proportion to its discharge (less than 1 percent), the Twin Falls sewage-treatment plant was a major source of total phosphorus (13 percent). A comparison of discharge and loading in water year 1995 with estimates of instream transport showed a good correlation (relative difference of less than 15 percent) for discharge, total organic nitrogen, dissolved nitrite plus nitrate, total nitrogen, and total phosphorus. Estimates of dissolved ammonia and suspended sediment loads correlated poorly with instream transport; relative differences were about 79 and 61 percent, respectively. The pesticides EPTC, atrazine, desethylatrazine, metolachlor, and alachlor were the most commonly detected in the upper Snake River Basin and accounted for about 75 percent of all pesticide detections. All pesticides detected were at concentrations less than 1 microgram per liter and below water-quality criteria established by the U.S. Environmental Protection Agency. In samples collected from two small agriculturally dominated tributary basins, the largest number and concentrations of pesticides were detected in May and June following early growing season applications. At one of the sites, the pesticide atrazine and its metabolite desethylatrazine were detected throughout the year. On the basis of 37 samples collected basinwide in May and June 1994, total annual subbasin applications and instantaneous instream fluxes of EPTC and atrazine showed logarithmic relations with coefficients of determination (R2 values) of 0.55 and 0.62, respectively. At the time of sampling, the median daily flux of EPTC was about 0.0001 percent of the annual quantity applied, whereas the median daily flux of atrazine was between 0.001 and 0.01 percent.

Idaho;Wyoming↗

USGS1997

Organochlorine compounds in fish tissue and bed sediment in the upper Snake River basin, Idaho and western Wyoming, 1992-94

Fish-tissue and bed-sediment samples were collected from 20 sites in the upper Snake River Basin in Idaho and western Wyoming as part of the National Water-Quality Assessment Program to determine the occurrence and distribution of organochlorine compounds. During 1992-94, 41 samples were analyzed for 28 different organochlorine compounds in whole-fish tissue and 32 compounds in bed sediment. Sites sampled were third- through seventh-order streams that represented three environmental settings: reference conditions, agricultural land use, and mixed (agricultural and urban) land use. Fourteen organochlorine compounds were detected in fish tissue and nine in bed sediment. All compounds detected in bed sediment also were detected in fish tissue. Fish-tissue and bed- sediment samples from agricultural and mixed land-use sites contained one or more organochlorine compounds. The most frequently detected compound at all sites was p,p'DDE, which was present in 80 percent of the fish-tissue and 30 percent of the bed-sediment samples. A maximum of three compounds were detected, all in fish-tissue samples from reference (forest and rangeland) sites. The highest number of compounds was detected in fish-tissue (nine) and bed-sediment (eight) samples from mixed land-use sites. No clear relation was apparent between the occurrence of external anomalies and fish-tissue contaminant concentrations or land use. The distribution of organochlorine compounds in the basin was related to land use. Total DDT was detected at sites in all land uses; total PCB was detected at only agricultural and mixed land-use sites. Total chlordane was detected in fish- tissue samples from primarily mixed land-use sites; samples from six of the eight sites contained detectable concentrations. Median concentrations of p,p'DDE in fish-tissue samples from mixed land- use sites were significantly higher (p<0.05) than from reference and agricultural sites. Significant positive relations between percent agricultural land and concentrations of total DDT (r 2 = 0.41) and lipid-normalized total DDT (r 2 =0.48) were observed. Concentrations of p,p'DDE, total PCB, total DDT, and toxaphene in fish-tissue samples from three mixed land-use sites equaled or exceeded national guidelines established for protection of fish-eating wildlife: Portneuf River at Pocatello, total PCB; Rock Creek at Twin Falls, p,p'DDE, total DDT, and toxaphene; and Snake River near Buhl, p,p'DDE and total DDT. Concentrations of total DDT and p,p'DDE in 32 and 34 percent of fish-tissue samples, respectively, analyzed during this study exceeded the 1980-81 U.S. Fish and Wildlife Service/National Contaminant Biomonitoring Program (USFWS/NCBP) geometric mean concentrations. Concentrations of total PCB in samples from the Portneuf River at Pocatello and concentrations of toxaphene in samples from Rock Creek at Twin Falls also exceeded the USFWS/NCBP geometric mean concentrations. Comparisons of 1970-84 USFWS/NCBP concentrations of total DDT and total PCB in fish-tissue samples from the Snake River near Hagerman with concentrations measured during this study indicated a decreasing trend. Concentrations of p,p'DDE in all sediment samples from Rock Creek at Twin Falls exceeded the Canadian Probable Effect Level guideline. Total PCB was detected in sediment from only one site, Portneuf River at Pocatello, which was also the only site where concentrations of total PCB in fish tissue were elevated. Because organochlorine compounds are lipophilic and tend to bioaccumulate in tissue, fish are a better indicator of organochlorine contaminant occurrence and distribution than are bed sediment or water in the upper Snake River Basin. Some of the highest concentrations of organochlorine contaminants in tissue and sediment in the basin were detected at sites receiving irrigation- return flows. Results of this study support the importance of controlling sediment erosion on irrigated land to reduce the quantity of contaminants entering streams that receive irrigation-return flows.

Idaho;Wyoming↗

USGS1997

Characteristics of fish assemblages and related environmental variables for streams of the upper Snake River basin, Idaho and western Wyoming, 1993-95

Fish assemblages and environmental variables were evaluated for 30 first- through seventh-order streams in the upper Snake River Basin, Idaho and western Wyoming. Data were collected as part of the National Water-Quality Assessment Program to characterize aquatic biota and associated habitats in surface water. Sampling sites represented major stream types in the basin large river, agricultural, and least-disturbed reference streams and springs in forested and (or) rangeland watersheds. Twenty-four environmental variables representing various spatial scales, from watershed characteristics to instream habitat and physicochemical measures, were used to examine relations with fish assemblages. Twenty-six fish species in the families Catostomidae, Centrarchidae, Cottidae, Cyprinidae, Ictaluridae, Percidae, and Salmonidae were collected. Detrended correspondence analysis and canonical correspondence analysis differentiated fish assemblages on the basis of site type and showed that fish assemblages were most strongly correlated with percent agricultural and forest land uses, stream width, watershed size, and elevation. Fish assemblages did not correspond to the four major ecoregions in the basin. Comparisons between multiple-year and multiple-reach collections using Jaccard's coefficient of community similarity index generally indicated little difference in fish assemblages. Percent substrate fines, percent embeddedness, and specific conductance typically were higher for streams influenced by agricultural land use than for reference streams in forested and (or) rangeland watersheds. The number of native species, percent introduced species, percent omnivores, percent common carp, percent salmonids, and percent coldwater-adapted species varied according to site type. Percent omnivores and percent common carp were higher for large river and agricultural sites than for reference stream and spring sites. The introduction of intolerant salmonid species throughout the basin confounds the use of introduced species as a measure of environmental disturbance. Analysis offish metrics identified some large river and agricultural sites in the lower part of the basin that did not support viable coldwater fish assemblages. These sites characteristically were dominated by tolerant, warmwater-adapted species. The findings of this study support the waterquality- limited designation for the middle reach of the Snake River between Milner Dam and King Hill and provide a framework for developing indices of biotic integrity by using fish assemblages to evaluate water quality of streams in the upper Snake River Basin.

Idaho;Wyoming↗

USGS1997

Agricultural land-use classification using landsat imagery data, and estimates of irrigation water use in Gooding, Jerome, Lincoln, and Minidoka counties, 1992 water year, Upper Snake River basin, Idaho and western Wyoming

As part of the U.S. Geological Survey's National Water-Quality Assessment Program in the upper Snake River Basin study unit, land- and water-use data were used to describe activities that have potential effects on water quality, including biological conditions, in the basin. Land-use maps and estimates of water use by irrigated agriculture were needed for Gooding, Jerome, Lincoln, and Minidoka Counties (south-central Idaho), four of the most intensively irrigated counties in the study unit. Land use in the four counties was mapped from Landsat Thematic Mapper imagery data for the 1992 water year using the SPECTRUM computer program. Land-use data were field verified in 108 randomly selected sections (640 acres each); results compared favorably with land-use maps from other sources. Water used for irrigation during the 1992 water year was estimated using land-use and ancillary data. In 1992, a drought year, estimated irrigation withdrawals in the four counties were about 2.9 million acre-feet of water. Of the 2.9 million acre-feet, an estimated 2.12 million acre-feet of water was withdrawn from surface water, mainly the Snake River, and nearly 776,000 acre-feet was withdrawn from ground water. One-half of the 2.9 million acre-feet of water withdrawn for irrigation was considered to be lost during conveyance or was returned to the Snake River; the remainder was consumptively used by crops during the growing season.

Idaho;Wyoming↗