Quality of groundwater and surface water, Wood River Valley, south-central Idaho, July and August 2012

Abstract

For more information on the USGS-the Federal source for science about the Earth, its natural and living resources, natural hazards, and the environment, visit http://www.usgs.gov or call 1-888-ASK-USGS.For an overview of USGS information products, including maps, imagery, and publications, visit http://www.usgs.gov/pubprodTo order this and other USGS information products, visit http://store.usgs.gov Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government.Although this information product, for the most part, is in the public domain, it also may contain copyrighted materials as noted in the text. Permission to reproduce copyrighted items must be secured from the copyright owner. DatumsVertical coordinate information is referenced to the National Geodetic Vertical Datum of 1929 (NGVD29).Horizontal coordinate information is referenced to the North American Datum of 1927 (NAD 27).Altitude, as used in this report, refers to distance above the vertical datum. viThis page intentionally left blank. AbstractResidents and resource managers of the Wood River Valley of south-central Idaho are concerned about the effects that population growth might have on the quality of groundwater and surface water. As part of a multi-phase assessment of the groundwater resources in the study area, the U.S. Geological Survey evaluated the quality of water at 45 groundwater and 5 surface-water sites throughout the Wood River Valley during July and August 2012. Water samples were analyzed for field parameters (temperature, pH, specific conductance, dissolved oxygen, and alkalinity), major ions, boron, iron, manganese, nutrients, and Escherichia coli (E coli) and total coliform bacteria.This study was conducted to determine baseline water quality throughout the Wood River Valley, with special emphasis on nutrient concentrations. Water quality in most samples collected did not exceed U.S. Environmental Protection Agency standards for drinking water. E. coli bacteria, used as indicators of water quality, were detected in all five surface-water samples and in two groundwater samples collected. Some analytes have aesthetic-based recommended drinking water standards; one groundwater sample exceeded recommended iron concentrations. Nitrate plus nitrite concentrations varied, but tended to be higher near population centers and in agricultural areas than in tributaries and less populated areas. These higher nitrate plus nitrite concentrations were not correlated with boron concentrations or the presence of bacteria, common indicators of sources of nutrients to water. None of the samples collected exceeded drinking-water standards for nitrate or nitrite.The concentration of total dissolved solids varied considerably in the waters sampled; however a calciummagnesium-bicarbonate water type was dominant (43 out of 50 samples) in both the groundwater and surface water. Three constituents that may be influenced by anthropogenic activity (chloride, boron, and nitrate plus nitrite) ...

Aquatic biological communities and associated habitats at selected sites in the Big Wood River Watershed, south-central Idaho, 2014

“…Local resorts and numerous fly fishing guides provide services in the area that attract recreationists from around the world to the Big Wood River. The population of Blaine County depends on groundwater for domestic and public supply, either from privately-owned or municipal-supply wells (Hopkins and Bartolino, 2013). In contrast, irrigation for local agriculture is largely dependent on surface water supplies.…”

“…Farmland irrigation began as early as 1900 (Jones, 1952) and has since expanded, with increased agricultural water needs within the watershed. Periodic changes in discharge for the Big Wood River, particularly in the downstream reaches, have been directly related to seasonal patterns of surface and groundwater withdrawal for irrigation (Hopkins and Bartolino, 2013). Water use for irrigation typically occurs during the growing season between May and September, during which time discharge in the southwestern part of the watershed is diminished and portions of the river downstream of Bellevue can go dry.…”

“…The East Fork (13138000, RK 146) discharges to the Big Wood River main stem downstream of the town of Ketchum. The East Fork headwaters originate on land managed by the Bureau of Land Management that has a history of mining activity (Hopkins and Bartolino, 2013). The East Fork sampling site is located in a rural area dominated by small ranches.…”

“…These reports include (1) a description of trends in surface and groundwater hydrology (Skinner and others, 2007), (2) the development of a groundwater budget (Bartolino, 2009), (3) a hydrogeologic framework for the Wood River Valley aquifer system (Bartolino and Adkins, 2012), (4) a stream seepage and groundwater levels study (Bartolino, 2014), and (5) an evaluation of the quality of groundwater and surface-water supplies (Hopkins and Bartolino, 2013). Overall, these studies concluded that most of the water supply in the Big Wood River watershed is relatively unimpaired, with low concentrations of nutrients and low levels of fecal contamination, although elevated nutrient concentrations were reported in groundwater in the eastern part of the watershed.…”

“…Despite concerns about the sustainability of the health of the Big Wood River, there is a lack of long-term waterand biological-quality monitoring in the watershed (Hopkins and Bartolino, 2013). The information in this report is intended to characterize selected discharge, water quality, physical habitat, and biological properties of the Big Wood River and its major tributaries, and to provide ecologically relevant guidelines to help in the design and implementation of long-term monitoring efforts in the Big Wood River watershed.…”