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At least 1,441 records · Page 80Linked to original sources
USGS2006

Stability of low levels of perchlorate in drinking water and natural water samples

Perchlorate ion (ClO4-) is an environmental contaminant of growing concern due to its potential human health effects, impact on aquatic and land animals, and widespread occurrence throughout the United States. The determination of perchlorate cannot normally be carried out in the field. As such, water samples for perchlorate analysis are often shipped to a central laboratory, where they may be stored for a significant period before analysis. The stability of perchlorate ion in various types of commonly encountered water samples has not been generally examined-the effect of such storage is thus not known. In the present study, the long-term stability of perchlorate ion in deionized water, tap water, ground water, and surface water was examined. Sample sets containing approximately 1000, 100, 1.0, and 0.5 ??g l-1 perchlorate ion in deionized water and also in local tap water were formulated. These samples were analyzed by ion chromatography for perchlorate ion concentration against freshly prepared standards every 24 h for the first 7 days, biweekly for the next 4 weeks, and periodically after that for a total of 400 or 610 days for the two lowest concentrations and a total of 428 or 638 days for the high concentrations. Ground and surface water samples containing perchlorate were collected, held and analyzed for perchlorate concentration periodically over at least 360 days. All samples except for the surface water samples were found to be stable for the duration of the study, allowing for holding times of at least 300 days for ground water samples and at least 90 days for surface water samples. ?? 2006 Elsevier B.V. All rights reserved.

Analytica Chimica Acta↗
USGS2004

Historical trends in occurrence and atmospheric inputs of halogenated volatile organic compounds in untreated ground water used as a source of drinking water

Analyses of samples of untreated ground water from 413 community-, non-community- (such as restaurants), and domestic-supply wells throughout the US were used to determine the frequency of detection of halogenated volatile organic compounds (VOCs) in drinking-water sources. The VOC data were compiled from archived chromatograms of samples analyzed originally for chlorofluorocarbons (CFCs) by purge-and-trap gas chromatography with an electron-capture detector (GC-ECD). Concentrations of the VOCs could not be ascertained because standards were not routinely analyzed for VOCs other than trichloromonofluoromethane (CFC-11), dichlorodifluoromethane (CFC-12) and 1,1,2-trichloro-1,2,2-trifluoroethane (CFC-113). Nevertheless, the peak areas associated with the elution times of other VOCs on the chromatograms can be classified qualitatively to assess concentrations at a detection limit on the order of parts per quadrillion. Three or more VOCs were detected in 100% (percent) of the chromatograms, and 77.2% of the samples contained 10 or more VOCs. The maximum number of VOCs detected in any sample was 24. Modeled ground-water residence times, determined from concentrations of CFC-12, were used to assess historical trends in the cumulative occurrence of all VOCs detected in this analysis, as well as the occurrence of individual VOCs, such as CFC-11, carbon tetrachloride (CCl 4 ), chloroform and tetrachloroethene (PCE). The detection frequency for all of the VOCs detected has remained relatively constant from approximately 1940 to 2000; however, the magnitude of the peak areas on the chromatograms for the VOCs in the water samples has increased from 1940 to 2000. For CFC-11, CCl 4 , chloroform and PCE, small peaks decrease from 1940 to 2000, and large peaks increase from 1940 to 2000. The increase in peak areas on the chromatograms from analyses of more recently recharged water is consistent with reported increases in atmospheric concentrations of the VOCs. Approximately 44% and 6.7% of the CCl 4 and PCE detections, respectively, in pre-1940 water, and 68% and 62% of the CCl 4 and PCE detections, respectively, in water recharged in 2000 exceed solubility equilibrium with average atmospheric concentrations. These exceedences can be attributed to local atmospheric enrichment or direct contaminant input to ground-water flow systems. The detection of VOCs at concentrations indicative of atmospheric sources in 100% of the samples indicates that untreated drinking water from ground-water sources in the US recharged within the past 60 years has been affected by anthropogenic activity. Additional inputs from a variety of sources such as spills, underground injections and leaking landfills or storage tanks increasingly are providing additional sources of contamination to ground water used as drinking-water sources.

Science of the Total Environment↗
USGS2011

Water and heat transport in boreal soils: Implications for soil response to climate change

Soil water content strongly affects permafrost dynamics by changing the soil thermal properties. However, the movement of liquid water, which plays an important role in the heat transport of temperate soils, has been under-represented in boreal studies. Two different heat transport models with and without convective heat transport were compared to measurements of soil temperatures in four boreal sites with different stand ages and drainage classes. Overall, soil temperatures during the growing season tended to be over-estimated by 2–4 °C when movement of liquid water and water vapor was not represented in the model. The role of heat transport in water has broad implications for site responses to warming and suggests reduced vulnerability of permafrost to thaw at drier sites. This result is consistent with field observations of faster thaw in response to warming in wet sites compared to drier sites over the past 30 years in Canadian boreal forests. These results highlight that representation of water flow in heat transport models is important to simulate future soil thermal or permafrost dynamics under a changing climate.

Science of the Total Environment↗
USGS2014

The contamination of ground‐water by salt water near Parlin, New Jersey

The classic studies of Badon Ghyben [see 1 of “References” at end of paper] and Alexander Herzoerg [2].that defined the basic principles governing the relation between salt water and fresh water in water‐bearing sands are now fairly well known. They showed that fresh water floats on the heavier salt Water and that, under static conditions, the ratio between the head of the fresh water above mean sea‐level and the depth of the contact between fresh and salt water below mean sea‐level, is determined by the relative specific gravities of the two waters. Other studies have shown that under ordinary conditions there is little mixing between the fresh and salt waters, so that the zone of contact is narrow. Instances have been observed in which the chloride‐content of the water has ranged from a few parts to several thousand parts per million within a few feet. It would seem, therefore, that the basic conditions under which fresh and salt water occur together in water‐bearing sands are somewhat similar to those in the tidal estuaries of streams. The principal differences are caused by the frictional resistance of the sand which prevents rapid movements of both fluids and probably retards their mixing.

New Jersey↗
USGS2003

The use of stable isotope to evaluate water mixing and water use by flood plain trees along the Garonne valley

Before the confluence of the Tarn, the Garonne valley was the driest area in the entire south-west of France, due to the relatively low rainfall and low summer discharge of the Garonne River and its tributaries. The natural abundance of the stable isotope of oxygen (18O) and ionic charge of surface and ground water were used to estimate the water source for the Garonne River and phreatic subsurface water. We also measured these constituents in the sap of trees at several flood plain sites to better understand the source of water used by these trees. 18O signatures and conductivity in the Garonne River indicated that the predominance of water was from high altitude surface runoff from the Pyrenees Mountains. Tributary inputs had little effect on isotopic identity, but had a small effect on the conductivity. The isotopic signature and ionic conductivity of river water (??18O: -9.1??? to -9.0???, conductivity: 217-410??S/cm) was distinctly different from groundwater (??18O: -7.1??? to -6.6???, conductivity: 600-900??S/cm). Isotopic signatures from the sap of trees on the flood plain showed that the water source was shallow subsurface water (<30cm), whereas trees further from the river relied on deeper ground water (>1m). Trees at both locations maintained sap with ionic charges much greater (2.3-3.7x) than that of source water. The combined use of 18O signatures and ionic conductivity appears to be a potent tool to determine water sources on geographic scales, and source and use patterns by trees at the local forest scale. These analyses also show promise for better understanding of the effects of anthropogenic land-use and water-use changes on flood plain forest dynamics.

Isotopes in Environmental and Health Studies↗
USGS1955

Water rights in areas of ground-water mining

Ground-water mining, the progressive depletion of storage in a ground-water reservoir, has been going on for several years in some areas, chiefly in the Southwestern States. In some of these States a water right is based on ownership of land overlying the ground-water reservoir and does not depend upon putting the water to use; in some States a right is based upon priority of appropriation and use and may be forfeited if the water is allowed to go unused for a specified period, but ownership of land is not essential; and in several States both these doctrines or modifications thereof are accepted, and each applies to certain classes of water or to certain conditions of development. Experience to date indicates that a cure for ground-water mining does not necessarily depend upon the water-rights doctrine that is accepted in the area. Indeed, some recent court decisions have incorporated both the areal factor of the landownership doctrines and the time factor of the appropriation doctrine. Overdraft can be eliminated if water is available from another source to replace some of the water taken from the affected aquifer. In areas where no alternate source of supply is available at reasonable cost, public opinion so far appears to favor treating ground water as a nonrenewable resource comparable to petroleum and metals, and mining it until the supply is exhausted, rather than curbing the withdrawals at an earlier date.

Circular↗
USGS1951

Ground-water resources of the Paintrock irrigation project, Wyoming, with a section on the quality of the water

The ground-water conditions of the area covered by the Paintrock irrigation project, in north-central Wyoming, were investigated during the summer of 1947. The purpose of the study was to obtain a general evaluation of ground-water recharge, discharge, and storage in the area now irrigated and in the adjacent areas where additional lands are to be irrigated. Much of the area covered by this report consists of flat to gently sloping stream terraces and alluvial-bottoms along Nowood, Paintrock, and Medicine Lodge Creeks. The stream-terrace materials consist of fluviatile sand, clay, and gravel. The alluvium is very fine grained and in general has low permeability. The materials underlying the stream terraces and the bottomlands became progressively finer grained and less permeable downstream. The bedrock formations underlying the area studied range from the Madison limestone of Mississippian age to the Fort Union formation of Paleocene age. Beds have been folded into several prominent structures which trend northwest-southeast across the area. Several of the formations exposed in the area serve as aquifers and yield water to domestic and stock wells. The most important bedrock aquifers are the Fort Union, Lance, Meeteetee, Mesaverde, Frontier, Cloverly and Morrison formations , the Tensleep sandstone, the Amsden formation, and the Madison limestone. More than 7,000 feet of strata are exposed in the area, the older beds being exposed on the western flank of the Big Horn Range near the eastern end of the area. The quality of the water in the project ranges within wide limits. The concentration of dissolved solids in seven samples of ground water ranges from 279 parts per million for a water in the Tensleep sandstone to 4,590 parts per million for a water in the Morrison formation. The hardness as calcium carbonate (CaCO 3 ) ranges from 13 to 1,680 parts per million. Limited data on the quality of water in Nowood and Paintrock Creeks indicate that these waters are suitable for irrigation. The water in Paintrock Creek near Tensleep is higher in mineral content and hardness than the water upstream at Hyattville as a result of return flow of the irrigation water that is applied to farm lands above Tensleep.

Wyoming↗
USGS2007

Surface-Water Conditions in Georgia, Water Year 2005

INTRODUCTION The U.S. Geological Survey (USGS) Georgia Water Science Center-in cooperation with Federal, State, and local agencies-collected surface-water streamflow, water-quality, and ecological data during the 2005 Water Year (October 1, 2004-September 30, 2005). These data were compiled into layers of an interactive ArcReaderTM published map document (pmf). ArcReaderTM is a product of Environmental Systems Research Institute, Inc (ESRI?). Datasets represented on the interactive map are * continuous daily mean streamflow * continuous daily mean water levels * continuous daily total precipitation * continuous daily water quality (water temperature, specific conductance dissolved oxygen, pH, and turbidity) * noncontinuous peak streamflow * miscellaneous streamflow measurements * lake or reservoir elevation * periodic surface-water quality * periodic ecological data * historical continuous daily mean streamflow discontinued prior to the 2005 water year The map interface provides the ability to identify a station in spatial reference to the political boundaries of the State of Georgia and other features-such as major streams, major roads, and other collection stations. Each station is hyperlinked to a station summary showing seasonal and annual stream characteristics for the current year and for the period of record. For continuous discharge stations, the station summary includes a one page graphical summary page containing five graphs, a station map, and a photograph of the station. The graphs provide a quick overview of the current and period-of-record hydrologic conditions of the station by providing a daily mean discharge graph for the water year, monthly statistics graph for the water year and period of record, an annual mean streamflow graph for the period of record, an annual minimum 7-day average streamflow graph for the period of record, and an annual peak streamflow graph for the period of record. Additionally, data can be accessed through the layer's link to the National Water Inventory System Web (NWISWeb) Interface.

Georgia↗
USGS2001

Occurrence and distribution of volatile organic compounds in drinking water supplied by community water systems in the Northeast and Mid-Atlantic regions of the United States, 1993-98

Data on volatile organic compounds (VOCs) in drinking water supplied by community water systems (CWSs) are available for 12 Northeast and Mid-Atlantic States from 1993-98. The data are from 2,110 CWSs representing a 20 percent random selection of the total 10,749 active CWSs in the region. The data were collected for compliance monitoring under the Safe Drinking Water Act from both surface-and ground-water sources and largely represent samples of finished drinking water collected prior to distribution. Overall, 39 percent of the 2,110 randomly selected CWSs reported a detection of one or more VOCs at or above 1.0 μg/L (micrograms per liter). Although differences in analytical coverage complicate comparisons, in the 1,543 CWSs with THM data at or above 1.0 μg/L, 42 percent reported an occurrence of one or more THMs. The common detection of THMs in finished drinking water probably is related to their formation through the chlorination of drinking-water supplies. Comparatively, solvents, the next most frequently detected VOC group, were reported in 9.8 percent of 2,097 CWSs with solvent data at or above 1.0 μg/L, and gasoline components were detected in 9.0 percent of 2,098 CWSs with data at or above 1.0 μg/L. Individually, the THMs—chloroform, bromodichloromethane, chlorodibromomethane, and bromoform—were the most frequently detected VOCs ranging from 33 to 8 percent. The most frequently detected non-THM compound was methyl tert-butyl ether, which was identified in 8 percent of CWSs. Of the 2,110 randomly selected CWSs, 6 percent had at least one sample with one or more VOCs with a concentration above a Maximum Contaminant Level, Health Advisory, or Drinking-Water Advisory. VOCs were more frequently detected in drinking water from systems that are supplied by surface-water sources, or both surface-and ground-water sources, than in systems that are supplied exclusively by ground water, and from systems serving very large and large populations (serving <3,300 people) compared to systems serving medium and small populations (serving <3,300 people).

Fact Sheet↗
USGS2001

Water Supply in the Mojave River Ground-Water Basin, 1931-99, and the Benefits of Artificial Recharge

The Mojave River and the associated aquifer system are important water supplies in the Mojave Desert of southern California. The river and aquifer system are in hydraulic connection in many areas, and when flow conditions change in one, the other usually is affected. The river is an unpredictable source of water; therefore, residents of the basin rely almost entirely on ground water for their water supply. This reliance on ground water has resulted in overdraft conditions that have caused water-level declines, changes in the quantity and spatial distribution of recharge from the Mojave River, and loss of riparian habitat. The U.S. Geological Survey (USGS), in cooperation with the Mojave Water Agency (MWA), has completed several studies to determine the likely effects of overdraft on the ground-water and surface-water relations along the Mojave River. This report summarizes those studies, highlighting some of the simulation results from a ground-water flow model, and describes the ground-water and surface-water conditions of the Mojave River Basin.

Fact Sheet↗
USGS2005

Naturally Occurring Arsenic in Ground Water, Norman, Oklahoma, 2004, and Remediation Options for Produced Water

In 2000, the U.S. Environmental Protection Agency (EPA) reviewed the arsenic drinking water standard for public water supplies. Considering the available research and statistics on the health effects of arsenic ingestion, the EPA reduced the Maximum Contaminant Level (MCL) for public drinking water from 50 micrograms per liter (?g/L) to 10 ?g/L (U.S. Environmental Protection Agency, 2001a). As a result of the more stringent standard, the EPA estimates that about 3,000 public water providers across the United States must take action to meet the new standard before it becomes effective on January 23, 2006 (U.S. Environmental Protection Agency, 2001b). The City of Norman (City) is one of several Oklahoma municipalities affected by the new arsenic standard. About 20 percent of Norman?s water is supplied by wells completed in the Central Oklahoma (Garber-Wellington) aquifer; the rest is supplied by Lake Thunderbird (fig. 1) or purchased from Oklahoma City. The Norman well field is composed of 24 active wells, and water produced from about half of the wells will not be in compliance with the new MCL (figs. 2 and 3). Chemical treatment of water with elevated arsenic is possible, but it is generally cost prohibitive. Another costly solution is simply to abandon the high-arsenic wells and replace them with new wells in low-arsenic areas. In the next phase of well construction beginning in 2005, the City plans to construct as many as 30 new wells in northeast Norman (Bryan Mitchell, City of Norman, oral commun., 2005). The new wells will replace production lost to the new arsenic standard and add new production to keep pace with rapidly growing consumer demand. Well modification to exclude arsenic-bearing water from existing wells is a more cost-effective solution, but it requires a great deal of knowledge about local aquifer properties and individual well dynamics to decide which wells are good candidates for modification. With the goal of determining if well modification can be used to bring some of Norman?s high-arsenic wells into compliance with the new arsenic standard, the EPA Office of Research and Development (ORD) initiated a three-year research project in 2003 with participation from the U.S. Geological Survey (USGS), Oklahoma State University, and the City of Norman. The primary objectives of the project are to: (1) determine where naturally occurring arsenic is entering wells by collecting water samples at different depths, (2) investigate the utility of new methods for collecting water-quality data in a pumping well, (3) better understand the stratigraphy and composition of aquifer rocks, (4) assess 10 wells for the possibility of arsenic remediation by well modification, and (5) evaluate the effectiveness of well modification in bringing marginal wells into compliance with the new arsenic MCL. The purpose of this report is to describe the occurrence of arsenic in ground water near Norman, Oklahoma, and available options for reducing arsenic concentrations in produced ground water.

Fact Sheet↗
USGS2006

Ground water in the Anchorage area, Alaska: Meeting the challenges of ground-water sustainability

Ground water is an important component of Anchorage's water supply. During the 1970s and early 80s when ground water extracted from aquifers near Ship Creek was the principal source of supply, area-wide declines in ground-water levels resulted in near record low streamflows in Ship Creek. Since the importation of Eklutna Lake water in the late 1980s, ground-water use has been reduced and ground water has contributed 14-30 percent of the annual supply. As Anchorage grows, given the current constraints on the Eklutna Lake water availability, the increasing demand for water could place an increasing reliance on local ground-water resources. The sustainability of Anchorage's ground-water resources challenges stakeholders to develop a comprehensive water-resources management strategy.

Alaska↗
USGS1998

Geology, ground-water flow, and dissolved-solids concentrations in ground water along hydrogeologic sections through Wisconsin aquifers

A cooperative project between the U.S. Geological Survey (USGS) and the Wisconsin Department of Natural Resources (DNR) was begun with the objectives of describing water quality and its relation to the hydrology of Wisconsin's principal aquifers and summarizing instances of ground-water contamination and quality problems from information available in DNR files. The first objective was met by a hydrologic investigation done by the USGS, and the second, by preparation of a report by the DNR, for their internal use, that describes the State's water resources and known ground-water quality and contamination problems and makes policy recommendations for ground-water management. The USGS investigation was divided into two phases. The first phase consisted of compiling available water-quality and hydrogeologic data and collecting new data to describe general regional water-quality and hydrogeologic relations within and between Wisconsin aquifers. The second phase began concurrently with the later part of the first phase and consisted of an areal description of water quality and flow in the State's shallow aquifer system (Kammerer, 1995). The overall purpose of this investigation was to provide a regional framework that could serve as a basis for intensive local and site specific ground-water investigations by State and local government agencies. This report presents the results of the first phase of the USGS investigation. Regional hydrogeologic and water-quality relations within and between aquifers are shown along 15 hydrogeologic sections that traverse the State. Maps are used to show surficial geology of bedrock and unconsolidated deposits and horizontal direction of ground-water flow. Interpretations on the maps and hydrogeologic sections are based on data from a variety of sources and provide the basis for the areal appraisal of water quality in the State's shallow aquifer system in the second phase of the investigation.

Wisconsin↗
USGS2002

Water-level altitudes 2002 and water-level changes in the Chicot, Evangeline, and Jasper aquifers and compaction 1973-2001 in the Chicot and Evangeline aquifers, Houston-Galveston region, Texas

This report is one in an annual series of reports that depicts water-level altitudes and water-level changes in the Chicot, Evangeline, and Jasper aquifers, and compaction in the Chicot and Evangeline aquifers in the Houston-Galveston region. The Houston-Galveston region comprises Harris, Galveston, Fort Bend, Waller, and Montgomery Counties and adjacent parts of Brazoria, Grimes, Walker, San Jacinto, Liberty, and Chambers Counties. The report was prepared in cooperation with the Harris-Galveston Coastal Subsidence District, the City of Houston, and the Fort Bend Subsidence District. For the Chicot and Evangeline aquifers, maps show approximate water-level altitudes in 2002, water-level changes from 2001 to 2002, approximate water-level changes from 1977 to 2002, lines of zero water-level change for intervals increasing in 5-year increments beginning with 1977–82, and approximate water-level changes from 1990 to 2002 (in the Fort Bend subregion [Fort Bend County and adjacent areas]) (figs. 1–10). For the Jasper aquifer, maps show approximate water-level altitudes in 2002 and water-level changes from 2001 to 2002 and 2000 to 2002 (figs. 11–13). The report also contains a map showing extensometer (well equipped with compaction monitor) site locations (fig. 14) and graphs showing measured compaction of subsurface material at selected sites from 1973 or later to 2001 (fig. 15). The U.S. Geological Survey (USGS) has published annual reports of water-level altitudes and water-level changes for the Chicot and Evangeline aquifers in the Houston-Galveston region since 1979; and separate annual reports of same for the Fort Bend subregion since 1990. The USGS published its first water-level-altitude map for the Jasper aquifer in the greater Houston area (primarily Montgomery County) in 2001. This year (2002), the altitude and change maps for the three aquifers are in this report.

Texas↗
USGS2004

Water-level altitudes 2003 and water-level changes in the Chicot, Evangeline, and Jasper aquifers and compaction 1973–2015 in the Chicot and Evangeline aquifers, Houston-Galveston region, Texas

This report is one in an annual series of reports that depicts water-level altitudes and water-level changes in the Chicot, Evangeline, and Jasper aquifers, and compaction in the Chicot and Evangeline aquifers in the Houston-Galveston region. The Houston-Galveston region comprises Harris, Galveston, Fort Bend, Waller, and Montgomery Counties and adjacent parts of Brazoria, Grimes, Walker, San Jacinto, Liberty, and Chambers Counties. The report was prepared in cooperation with the Harris-Galveston Coastal Subsidence District, the City of Houston, and the Fort Bend Subsidence District. For the Chicot and Evangeline aquifers, maps show approximate water-level altitudes in 2003, water-level changes from 2002 to 2003, approximate water-level changes from 1990 to 2003, approximate water-level changes from 1977 to 2003, and lines of zero water-level change for selected intervals beginning with 1977–82 (figs. 1, 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 - 10 ). For the Jasper aquifer, maps show approximate water-level altitudes in 2003 and water-level changes from 2002 to 2003 and 2000 to 2003 (figs. 11 , 12 , 13 ). The report also contains a map showing borehole extensometer (well equipped with compaction monitor) site locations ( fig. 14 ) and graphs showing measured compaction of subsurface material at these sites from 1973 or later to 2002 ( fig. 15 ). The U.S. Geological Survey (USGS) has published annual reports of water-level altitudes and water-level changes for the Chicot and Evangeline aquifers in the Houston-Galveston region since 1979; and annual reports of same for the Fort Bend subregion (Fort Bend County and adjacent areas) since 1990. The USGS published its first water-level-altitude map for the Jasper aquifer in the greater Houston area (primarily Montgomery County) in 2001. The 2003 altitude and change maps for the three aquifers are included in this report.

Texas↗
USGS2005

Water-level altitudes 2005 and water-level changes in the Chicot, Evangeline, and Jasper aquifers and compaction 1973-2004 in the Chicot and Evangeline aquifers, Houston-Galveston region, Texas

This report is one in an annual series of reports that depicts water-level altitudes and water-level changes in the Chicot, Evangeline, and Jasper aquifers, and compaction in the Chicot and Evangeline aquifers in the Houston-Galveston region. The Houston-Galveston region comprises Harris, Galveston, Fort Bend, Waller, and Montgomery Counties and adjacent parts of Brazoria, Grimes, Walker, San Jacinto, Liberty, and Chambers Counties. The report was prepared in cooperation with the Harris-Galveston Coastal Subsidence District, the City of Houston, the Fort Bend Subsidence District, and the Lone Star Groundwater Conservation District. For the Chicot and Evangeline aquifers, maps show approximate water-level altitudes in 2005, water-level changes from 2004 to 2005, and approximate water-level changes from 2000 to 2005, from 1990 to 2005, and from 1977 to 2005 (figs. 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , and 10 ). For the Jasper aquifer, maps show approximate water-level altitudes in 2005 and water-level changes from 2004 to 2005 and 2000 to 2005 (figs. 11 , 12 , and 13 ). The report also contains a map showing borehole extensometer (well equipped with compaction monitor) site locations ( fig. 14 ) and graphs showing measured compaction of subsurface material at these sites from 1973 or later to 2004 ( fig. 15 ). The U.S. Geological Survey (USGS) has published annual reports of water-level altitudes and water-level changes for the Chicot and Evangeline aquifers in the Houston-Galveston region since 1979; and annual reports of same for the Fort Bend subregion (Fort Bend County and adjacent areas) since 1990. The USGS published its first water-level-altitude map for the Jasper aquifer in the greater Houston area (primarily Montgomery County) in 2001. The 2005 water-level-altitude and water-level-change maps for the three aquifers are included in this report.

Texas↗
USGS2006

Water-level altitudes 2006 and water-level changes in the Chicot, Evangeline, and Jasper aquifers and compaction 1973-2005 in the Chicot and Evangeline aquifers, Houston-Galveston region, Texas

This report is one in an annual series of reports that depicts water-level altitudes and water-level changes in the Chicot, Evangeline, and Jasper aquifers, and compaction in the Chicot and Evangeline aquifers in the Houston-Galveston region. The Houston-Galveston region comprises Harris, Galveston, Fort Bend, Waller, and Montgomery Counties and adjacent parts of Brazoria, Grimes, Walker, San Jacinto, Liberty, and Chambers Counties. The report was prepared in cooperation with the Harris-Galveston Coastal Subsidence District, the City of Houston, the Fort Bend Subsidence District, and the Lone Star Groundwater Conservation District. For the Chicot and Evangeline aquifers, maps show approximate water-level altitudes in 2006, water-level changes from 2005 to 2006, and approximate water-level changes from 2001 to 2006, from 1990 to 2006, and from 1977 to 2006 (figs. 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 ). For the Jasper aquifer, maps show approximate water-level altitudes in 2006 and water-level changes from 2005 to 2006 and 2000 to 2006 (figs. 11 , 12 , 13 ). The report also contains a map showing borehole extensometer (well equipped with compaction monitor) site locations ( fig. 14 ) and graphs showing measured compaction of subsurface material at these sites from 1973 or later to 2005 ( fig. 15 ). The U.S. Geological Survey (USGS) has published annual reports of water-level altitudes and water-level changes for the Chicot and Evangeline aquifers in the Houston-Galveston region since 1979; and annual reports of same for the Fort Bend subregion (Fort Bend County and adjacent areas) since 1990. The USGS published its first water-level-altitude map for the Jasper aquifer in the greater Houston area (primarily Montgomery County) in 2001. The 2006 water-level-altitude and water-level-change maps for the three aquifers are included in this report.

Texas↗
USGS2007

Compilation of water-resources data for Montana, water year 2006

The U.S. Geological Survey, Montana Water Science Center, in cooperation with other Federal, State, and local agencies, and Tribal governments, collects a large amount of data pertaining to the water resources of Montana each water year. This report is a compilation of Montana site-data sheets for the 2006 water year, which consists of records of stage and discharge of streams; water quality of streams and ground water; stage and contents of lakes and reservoirs; water levels in wells; and precipitation data. Site-data sheets for selected stations in Canada and Wyoming also are included in this report. The data for Montana, along with data from various parts of the Nation, are included in 'Water-Resources Data for the United States, Water Year 2006', which is published as U.S. Geological Survey Water-Data Report WDR-US-2006 and is available at http://pubs.water.usgs.gov/wdr2006. Additional water year 2006 data collected at crest-stage gage and miscellaneous-measurement stations were collected but were not published. These data are stored in files of the U.S. Geological Survey Montana Water Science Center in Helena, Montana, and are available on request.

Montana↗