SEARCH · Geology Reports

Results for “Southwest Hydrology”

Search indexed USGS publications on groundwater, aquifers, geologic maps, mineral resources and earthquakes. Explore source records by subject and place.

SourceResearch connectionFrom yearThrough year

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 325 records · Page 18Linked to original sources

USGS1996

A watershed-scale approach to tracing metal contamination in the environment

Introduction Public policy during the 1800's encouraged mining in the western United States. Mining on Federal lands played an important role in the growing economy creating national wealth from our abundant and diverse mineral resource base. The common industrial practice from the early days of mining through about 1970 in the U.S. was for mine operators to dispose of the mine wastes and mill tailings in the nearest stream reach or lake. As a result of this contamination, many stream reaches below old mines, mills, and mining districts and some major rivers and lakes no longer support aquatic life. Riparian habitats within these affected watersheds have also been impacted. Often, the water from these affected stream reaches is generally not suitable for drinking, creating a public health hazard. The recent Department of Interior Abandoned Mine Lands ( AML ) Initiative is an effort on the part of the Federal Government to address the adverse environmental impact of these past mining practices on Federal lands. The AML Initiative has adopted a watershed approach to determine those sites that contribute the majority of the contaminants in the watershed. By remediating the largest sources of contamination within the watershed, the impact of metal contamination in the environment within the watershed as a whole is reduced rather than focusing largely on those sites for which principal responsible parties can be found. The scope of the problem of metal contamination in the environment from past mining practices in the coterminous U.S. is addressed in a recent report by Ferderer (1996). Using the USGS 1:2,000,000-scale hydrologic drainage basin boundaries and the USGS Minerals Availability System ( MAS ) data base, he plotted the distribution of 48,000 past-producing metal mines on maps showing the boundaries of lands administered by the various Federal Land Management Agencies ( FLMA ). Census analysis of these data provided an initial screening tool for prioritization of watersheds in the western U.S. A different approach to the scope of the abandoned mine problem (Church et al., 1996a) is shown by the water quality data collected by the States under the Clean Water Act, section 305(b). These data document the stream reaches affected by metals from naturally occurring sources as well as from mining, or mineral resource extraction. Permitted discharges from active industrial and mine sites are not covered in the 305(b) data base. Local citizens and state and federal agencies are all part of the collaborative decision process used to select the drainage basins chosen for the AML Initiative pilot studies. Data gathered by these three entities were brought to bear on the watershed selection process. The USGS prepared data available from Federal data bases in the form of interpretative GIS products. Maps of the states of Colorado (Plumlee et al., 1995) and a similar study of the state of Montana ( USGS , unpublished data) were used to select the Animas watershed in southwestern Colorado and the Boulder watershed southwest of Helena Montana as the pilot study areas for the AML Initiative. Thus, the watersheds selected for study were public decisions made on the basis of available scientific data. The role of the U.S. Geological Survey in the Abandoned Mine Land Initiative is outlined in Buxton et al. (1997). The watershed approach to metals contamination in the environment has been studied in several drainage basins (Church et al., 1993, 1994, 1995, 1996b; Kimball et al., 1995). The underlying principles used to successfully discriminate between sources and to quantify the impact of these sources on the environment are the subject of this report.

Conference Paper↗

USGS2003

Flow origin, drainage area, and hydrologic characteristics for headwater streams in the mountaintop coal-mining region of Southern West Virginia, 2000-01

Characteristics of perennial and intermittent headwater streams were documented in the mountaintop removal coal-mining region of southern West Virginia in 2000–01. The perennial-flow origin points were identified in autumn during low base-flow conditions. The intermittent-flow origin points were identified in late winter and early spring during high base-flow conditions. Results of this investigation indicate that the median drainage area upstream of the origin of intermittent flow was 14.5 acres, and varied by an absolute median of 3.4 acres between the late winter measurements of 2000 and early spring measurements of 2001. Median drainage area in the northeastern part of the study unit was generally larger (20.4 acres), with a lower median basin slope (322 feet per mile) than the southwestern part of the study unit (12.9 acres and 465 feet per mile, respectively). Both of the seasons preceding the annual intermittent flow visits were much drier than normal. The West Virginia Department of Environmental Protection reports that the median size of permitted valley fills in southern West Virginia is 12.0 acres, which is comparable to the median drainage area upstream of the ephemeralintermittent flow point (14.5 acres). The maximum size of permitted fills (480 acres), however, is more than 10 times the observed maximum drainage area upstream of the ephemeral-intermittent flow point (45.3 acres), although a single valley fill may cover more than one drainage area. The median drainage area upstream of the origin of perennial flow was 40.8 acres, and varied by an absolute median of 18.0 acres between two annual autumn measurements. Only basins underlain with mostly sandstone bedrock produced perennial flow. Perennial points in the northeast part of the study unit had a larger median drainage area (70.0 acres) and a smaller median basin slope (416 feet per mile) than perennial points in the southwest part of the study unit (35.5 acres and 567 feet per mile, respectively). Some streams were totally dry for one or both of the annual October visits. Both of the seasons preceding the October visits had near normal to higher than normal precipitation. These dry streams were adjacent to perennial streams draining similarly sized areas, suggesting that local conditions at a firstorder- stream scale determine whether or not there will be perennial flow. Headwater-flow rates varied little from year to year, but there was some variation between late winter and early spring and autumn. Flow rates at intermittent points of flow origin ranged from 0.001 to 0.032 cubic feet per second, with a median of 0.017 cubic feet per second. Flow rates at perennial points of flow origin ranged from 0.001 to 0.14 cubic feet per second, with a median of 0.003 cubic feet per second.

West Virginia↗

USGS2018

Systematic variation in evapotranspiration trends and drivers across the Northeastern United States

The direction and magnitude of responses of evapotranspiration (ET) to climate change are important to understand, as ET represents a major water and energy flux from terrestrial ecosystems, with consequences that feed back to the climate system. We inferred multidecadal trends in water balance in 11 river basins (1940–2012) and eight smaller watersheds (with records ranging from 18 to 61 years in length) in the Northeastern United States. Trends in river basin actual ET (AET) varied across the region, with an apparent latitudinal pattern: AET increased in the cooler northern part of the region (Maine) but decreased in some warmer regions to the southwest (Pennsylvania–Ohio). Of the four small watersheds with records longer than 45 years, two fit this geographic pattern in AET trends. The differential effects of the warming climate on AET across the region may indicate different mechanisms of change in more‐ vs. less‐energy‐limited watersheds, even though annual precipitation greatly exceeds potential ET across the entire region. Correlations between AET and time series of temperature and precipitation also indicate differences in limiting factors for AET across the Northeastern U.S. climate gradient. At many sites across the climate gradient, water‐year AET correlated with summer precipitation, implying that water limitation is at least transiently important in some years, whereas correlations with temperature indices were more prominent in northern than southern sites within the region.

Hydrological Processes↗

USGS2009

Does mobility explain variation in colonisation and population recovery among stream fishes?

1. Colonisation and population recovery are crucial to species persistence in environmentally variable ecosystems, but are poorly understood processes. After documenting movement rates for several species of stream fish, we predicted that this variable would influence colonisation rates more strongly than local abundance, per cent occupancy, body size and taxonomic family. We also predicted that populations of species with higher movement rates would recover more rapidly than species with lower movement rates and that assemblage structure would change accordingly. 2. To test these predictions, we removed fishes from a headwater and a mainstem creek in southwest Virginia and monitored colonisation over a 2-year period. Using an information–theoretic approach, we evaluated the relative plausibility of 15 alternative models containing different combinations of our predictor variables. Our best-supported model contained movement rate and abundance and was 41 times more likely to account for observed patterns in colonisation rates than the next-best model. Movement rate and abundance were both positively related to colonisation rates and explained 88% of the variation in colonisation rates among species. 3. Population recovery, measured as the per cent of initial abundance restored, was also positively associated with movement rate. One species recovered within 3 months, most recovered within 2 years, but two species still had not recovered after 2 years. Despite high variation in recovery, the removal had only a slight impact on assemblage structure because species that were abundant in pre-removal samples were also abundant in post-removal samples. 4. The significance of interspecific variation in colonisation and recovery rates has been underappreciated because of the widely documented recovery of stream fish assemblages following fish kills and small-scale experimental defaunations. Our results indicate that recovery of the overall assemblage does not imply recovery of each component species. Populations of species that are rare and less mobile will recover more slowly and will be more vulnerable to extinction in systems where chemical spills, hydrological alteration, extreme droughts and other impacts are frequent.

Virginia↗

USGS2018

Geochemistry of groundwater in the eastern Snake River Plain aquifer, Idaho National Laboratory and vicinity, eastern Idaho

Nuclear research activities at the U.S. Department of Energy (DOE) Idaho National Laboratory (INL) in eastern Idaho produced radiochemical and chemical wastes that were discharged to the subsurface, resulting in detectable concentrations of some waste constituents in the eastern Snake River Plain (ESRP) aquifer. These waste constituents may pose risks to the water quality of the aquifer. In order to understand these risks to water quality the U.S. Geological Survey, in cooperation with the DOE, conducted a study of groundwater geochemistry to improve the understanding of hydrologic and chemical processes in the ESRP aquifer at and near the INL and to understand how these processes affect waste constituents in the aquifer. Geochemistry data were used to identify sources of recharge, mixing of water, and directions of groundwater flow in the ESRP aquifer at the INL. The geochemistry data were analyzed from 167 sample sites at and near the INL. The sites included 150 groundwater, 13 surface-water, and 4 geothermal-water sites. The data were collected between 1952 and 2012, although most data collected at the INL were collected from 1989 to 1996. Water samples were analyzed for all or most of the following: field parameters, dissolved gases, major ions, dissolved metals, isotope ratios, and environmental tracers. Sources of recharge identified at the INL were regional groundwater, groundwater from the Little Lost River (LLR) and Birch Creek (BC) valleys, groundwater from the Lost River Range, geothermal water, and surface water from the Big Lost River (BLR), LLR, and BC. Recharge from the BLR that may have occurred during the last glacial epoch, or paleorecharge, may be present at several wells in the southwestern part of the INL. Mixing of water at the INL primarily included mixing of surface water with groundwater from the tributary valleys and mixing of geothermal water with regional groundwater. Additionally, a zone of mixing between tributary valley water and regional groundwater, trending southwesterly, extended from near the northeastern boundary of the INL to the southern boundary of the INL. Groundwater flow directions for regional groundwater were southwesterly, and flow directions for tributary groundwater were southeasterly upon entering the ESRP, but eventually began to flow southwesterly in a direction parallel with regional groundwater. Several discrepancies were identified from comparison of sources of recharge determined from geochemistry data and backward particle tracking with a groundwater-flow model. Some discrepancies observed in the particle tracking results included representation of recharge from BC near the north INL boundary, groundwater from the BC valley not extending far enough south, regional groundwater that extends too far west in the southern part of the INL, and no representation of recharge from geothermal water in model layer 1 or recharge from the BLR in the southwestern part of the INL.

Idaho↗

USGS2001

Selected hydrologic data for Cedar Valley, Iron County, southwestern Utah, 1930-2001

This report presents hydrologic data collected by the U. S. Geological Survey from 1930 to 2001 with emphasis on data collected from 1997 to 2001 as part of a study of ground-water resources in Cedar Valley, Iron County, southwestern Utah (fig. 1). Data collected prior to this study are also presented to show long-term trends. Data were collected during this study in cooperation with the Central Iron County Water Conservancy District; Utah Department of Natural Resources, Division of Water Resources; Utah Department of Environmental Quality, Division of Water Quality; Cedar City; and Enoch City; as part of a study to better understand the ground-water resources of Cedar Valley and to assess possible effects of increased ground-water withdrawal on water quality. Quality of ground water in Cedar Valley is variable and water suppliers need to know if additional water resources can be developed without drawing water of lower quality into public-supply wells. Cedar Valley is in central Iron County at the transitional boundary between the Basin and Range and Colorado Plateau physiographic provinces described by Hunt (1974) and covers about 570 mi2. Additional data from wells west of Cedar Valley and to the south in the vicinity of Kanarraville in the Virgin River drainage (Colorado River Basin) adjacent to the study area are included. Cedar Valley is bounded on the east by the Markagunt Plateau and Red Hills, on the southwest by the Harmony Mountains, on the west by a complex of low hills, and on the north by the Black Mountains. Altitudes in the study area range from about 5,300 ft in Mud Spring Canyon to about 10,400 ft at Blowhard Mountain to the east.

Utah↗

USGS1984

Application of a parameter-estimation technique to modeling the regional aquifer underlying the eastern Snake River Plain, Idaho

A nonlinear, least-squares regression technique for the estimation of ground-water flow model parameters was applied to the regional aquifer underlying the eastern Snake River Plain, Idaho. The computer program simulates two-dimensional, steady-state ground-water flow. Hydrologic data for the 1980 water year were used to calculate recharge rates, boundary fluxes, and spring discharges. Groundwater use was estimated from irrigated land maps and crop consumptive-use figures. These estimates of ground-water withdrawal, recharge rates, and boundary flux, along with leakance, were used as known values in the model calibration of transmissivity. Leakance values were adjusted between regression solutions by comparing model-calculated to measured spring discharges. In other simulations, recharge and leakance also were calibrated as prior information regression parameters, which limits the variation of these parameters using a normalized standard error of estimate. Results from a best-fit model indicate a wide areal range in transmissivity from about 0.05 to 44 feet squared per second and in leakance from about 2.2 x 10 -9 to 6.0 x 10 -8 feet per second per foot. Along with parameter values, model statistics also were calculated, including the coefficient of correlation between computed and observed head (0.996), standard error of the estimates of head (40 feet), and parameter coefficients of variation (about 10-40 per-cent). Additional boundary flux was added in some areas during calibration to achieve proper fit to ground-water flow directions. Model fit improved significantly when areas that violated model assumptions were removed. Model fit also improved when y-direction (northwest-southeast) transmissivity values were larger than x-direction (northeast-southwest) transmissivity values. The model was most sensitive to changes in recharge, and in some areas, to changes in transmissivity, particularly near the spring discharge area from Milner to King Hill.

Idaho↗

USGS2010

The potential influence of changing climate on the persistence of salmonids of the inland west

The Earth's climate warmed steadily during the 20th century, and mean annual air temperatures are estimated to have increased by 0.6°C (Intergovernmental Panel on Climate Change, 2007). Although many cycles of warming and cooling have occurred in the past, the most recent warming period is unique in its rate and magnitude of change (Siegenthaler and others, 2005) and in its association with anthropogenic emissions of greenhouse gases (Intergovernmental Panel on Climate Change , 2007). The climate in the western United States warmed in concert with the global trend but at an accelerated rate (+0.8°C during the 20th century; Saunders and others, 2008). The region could also prove especially sensitive to future changes because the relatively small human population is growing rapidly, as are demands on limited water supplies. Regional hydrological patterns are dominated by seasonal snow accumulation at upper elevations. Most of the region is relatively dry, and both terrestrial and aquatic ecosystems are strongly constrained b y water availability (Barnett and others, 2008; Brown and others, 2008). Stream environments are dynamic and climatically extreme, and salmonid fishes are the dominant elements of the native biodiversity (McPhail and Lindsey, 1986; Waples and others, 2008). Salmonids have broad economic and ecologic importance, but a century of intensive water resource development, nonnative fish stocking, and land use has significantly reduced many populations and several taxa are now protected under the Endangered Species Act (Thurow and others, 1997; Trotter, 2008). Because salmonids require relatively pristine, cold water environments and are often isolated in headwater habitats, members of this group may be especially vulnerable to the effects of a warming climate (Keleher and Rahel, 1996; Rieman and others, 2007; Williams and others, 2009). Warming during the 20th century drove a series of environmental trends that have profound implications for many aspects of salmonid habitat, including disturbance regimes such as wildfire, and unfavorable changes to thermal and hydrologic properties of aquatic systems. Warmer air temperatures have been associated with decreased winter snow accumulations, have accelerated snowmelt, and have advanced the timing of peak runoff by several days to weeks across most of western North America (Stewart and others, 2005; Barnett and others, 2008). Less snow and earlier runoff decrease aquifer recharge, make less water available for groundwater inputs to streams, and are contributing to widespread decreases in summer low flows (Stewart and others, 2005; Rood and others, 2008; Luce and Holden 2009). Interannual variability in stream flow is increasing, as is the persistence of multi-year extreme conditions (McCabe and others, 2004; Pagano and Garen 2005). In many areas of western North America, flood risks have increased in association with warmer temperatures during the 20th century (Hamlet and Lettenmaier, 2005). Streams where midwinter temperatures are near freezing have proven especially sensitive to increased flooding because of associated transitional hydrological patterns (mixtures of rainfall and snowmelt) and propensity for occasional rain-on-snow events to rapidly melt winter snowpack and generate large floods (Hamlet and Lettenmaier, 2005). Stream temperatures in many areas are increasing (Peterson and Kitchell, 2001; Morrison and others, 2002; Bartholow, 2005; Kaushal and others, 2010), due to both air temperature increases and reduced summer flows that make streams more sensitive to warmer air temperatures (Isaak and others, 2010). In recent decades, wildfires have become more common across much of the western United States during periods of more frequent droughts (Westerling and others, 2006; Hoerling and Eischeid, 2007), and local stream temperature can increase in postfire environments (Gresswell, 1999; Dunham and others, 2007). Fire-related temperature increase within streams is commonly a transient phenomenon, lasting only until riparian vegetation has recovered (Gresswell, 1999); however, ongoing climate change could preclude recovery to higher stature, prefire vegetation types in some areas (McKenzie and others, 2004; van Mantgem and Stephenson, 2007), resulting in a loss of critical riparian shading. Additionally, when wildfires occur in steep mountain topographies, the vegetation that stabilize s soils on hillslopes is often killed and landslides become more prevalent (Gresswell, 1999). Landslides int o stream channels form debris flows composed of sediment slurries and dead trees that can scour channels to bedrock and further exacerbate stream heating, delay recovery of riparian areas, or extirpate fish populations (Gresswell, 1999; May and Gresswell, 2003; Dunham and others, 2007). Changes in stream environments will shift habitat distributions, sometimes unpredictably, in both time and space for many salmonid fishes. Water temperature fundamentally influences aquatic ecosystem health because distribution, reproduction, fitness, and survival of ectothermic organisms are inextricably linked to the thermal regime of the environment. Historically, research has focused on defining lethal thermal limits of salmonids (Eaton and others, 1995; Selong and others, 2001; Todd and others, 2008); however, water temperature is known to be important in biological processes at a variety of spatial scales and levels of biological organization (Rahel and Olden, 2008; McCullough and others, 2009). For instance, trout are affected directly by water temperature through feeding, metabolism, and growth rates, and indirectly by factors such as prey availability and species interactions (Wehrly and others, 2007; Rahel and Olden, 2008). Where cold water temperatures currently limit habitat suitability and distributions of some species (for example, at the highest and most northerly distributional extents; Nakano and others, 1996; Coleman and Fausch, 2007), a warming climate may gradually increase the quality and extent of suitable habitat. Over time, previously constrained populations are expected to expand into these new habitats and increase in number. Some evidence suggests this may already be happening in Alaska, where streams in recently deglaciated areas are being colonized by emigrants from nearby salmon and char populations (Milner and others, 2000). Unfortunately, many of the sensitive salmonid species that are often the focus of western managers are unlikely to benefit from future water temperature increases. Warmer stream temperatures will facilitate invasion by nonnative species that are broadly established in downstream areas into upstream areas where they will compete with native species (Rieman and others, 2006; Rahel and Olden, 2008; Fausch and others, 2009). In other cases, warmer stream temperatures will render thermally suitable habitats unsuitable in downstream areas and effect net losses of habitat because upstream distributions are often constrained by streams that are too small or steep (Hari and others, 2006; Isaak and others, 2010). Both scenarios are realistic for fish species like bull trout ( Salvelinus confluentus ) (Rieman and others, 2006; Rieman and others, 2007), the various subspecies of cutthroat trout ( Oncorhynchus clarkii ) (Williams and others, 2009), Gila trout ( Oncorhynchus gilae gilae ) (Kennedy and others, 2008), and Apache trout ( Oncorhynchus gilae apache ) (Rinne and Minckley, 1985; Carmichael and others, 1993). As native species are increasingly confined to smaller and more isolated habitats by a gradually warming climate, the effects of wildfires (whether related to lethal changes in water quality during a fire, channel debris flows, or chronic postfire warming ) could have greater proportional effects on remaining habitats (for example, Brown and others, 2001; Rieman and others, 2007). If these changes were accompanied by additional hydrologic alterations associated with changes to the magnitude, frequency, duration, timing, and rate of change of discharge patterns (Jager and others, 1999; Henderson and others, 2000), populations may begin to lose some of their historic resilience and become ever more susceptible to local extirpations. As dramatic and extensive as climatic and environmental trends are for salmonid habitats, global climate models (GCMs) project that many of these trends will continue and even accelerate until at least the middle of the 21st century (Intergovernmental Panel on Climate Change, 2007). Current projections suggest mean annual air temperatures will increase by an additional 1–3°C, and early indications are that climate trajectory is at the higher end of this range (Pittock, 2006; Raupach and others, 2007). Although predicted changes vary considerably, even the most conservative estimates suggest a warming rate that will be twice that observed during the 20th century. Projections for the midcentury are most certainly due to the effects of greenhouse gases already emitted or predicted in the short term, uncertainties of the effects of longer-term greenhouse gas emissions, short-term climate cycles, and process errors associated with climate models (Cox and Stephenson, 2007). Projections of changes in total precipitation are less certain than those for air temperatures, but most GCMs project relatively small changes in the Northwest, with the exception of slightly drier summer periods (Mote and others, 2008; Karl and others, 2009). In the Southwest, however, significant decreases (such as 15–30 percent ) are projected during most periods of the year, and this area is one of the few for which Intergovernmental Panel on Climate Change (2007) precipitation projections have a high level of certainty (Hoerling and Eischeid, 2007; Karl and others, 2009). Clearly, managers of native salmonids in the wester n United States should consider adjusting management strategies to accommodate a warmer and possibly drier future (Williams and others, 2009). Tools are needed to forecast where important changes may occur and how conservation efforts should be prioritized. In this Open-File Report, we document our initial efforts in this regard for 10 species and subspecies of inland trout and Montana Arctic grayling ( Thymallus arcticus ) across the western United States.

Arizona, California, Colorado, Idaho, Montana, Nev↗

USGS2015

Hydrologic influences on water-level changes in the Eastern Snake River Plain aquifer at and near the Idaho National Laboratory, Idaho, 1949-2014

The U.S. Geological Survey, in cooperation with the U.S. Department of Energy, has maintained a water-level monitoring program at the Idaho National Laboratory (INL) since 1949 to systematically measure water levels to provide long-term information on groundwater recharge, discharge, movement, and storage in the eastern Snake River Plain (ESRP) aquifer. During 2014, water levels in the ESRP aquifer reached all-time lows for the period of record, prompting this study to assess the effect that future water-level declines may have on pumps and wells. Water-level data were compared with pump-setting depth to determine the hydraulic head above the current pump setting. Additionally, geophysical logs were examined to address changes in well productivity with water-level declines. Furthermore, hydrologic factors that affect water levels in different areas of the INL were evaluated to help understand why water-level changes occur. Review of pump intake placement and 2014 water-level data indicates that 40 wells completed within the ESRP aquifer at the INL have 20 feet (ft) or less of head above the pump. Nine of the these wells are located in the northeastern and northwestern areas of the INL where recharge is predominantly affected by irrigation, wet and dry cycles of precipitation, and flow in the Big Lost River. Water levels in northeastern and northwestern wells generally show water-level fluctuations of as much as 4.5 ft seasonally and show declines as much as 25 ft during the past 14 years. In the southeastern area of the INL, seven wells were identified as having less than 20 ft of water remaining above the pump. Most of the wells in the southeast show less decline over the period of record compared with wells in the northeast; the smaller declines are probably attributable to less groundwater withdrawal from pumping of wells for irrigation. In addition, most of the southeastern wells show only about a 1–2 ft fluctuation seasonally because they are less influenced by groundwater withdrawals for irrigation. In the southwestern area of the INL, 24 wells were identified as having less than 20 ft of water remaining above the pump. Wells in the southwest also only show small 1–2 ft fluctuations seasonally because of a lack of irrigation influence. Wells show larger fluctuation in water levels closer to the Big Lost River and fluctuate in response to wet and dry cycles of recharge to the Big Lost River. Geophysical logs indicate that most of the wells evaluated will maintain their current production until the water level declines to the depth of the pump. A few of the wells may become less productive once the water level gets to within about 5 ft from the top of the pump. Wells most susceptible to future drought cycles are those in the northeastern and northwestern areas of the INL.

Idaho↗

USGS1986

Application of a parameter-estimation technique to modeling the regional aquifer underlying the eastern Snake River plain, Idaho

A nonlinear, least-squares regression technique for the estimation of ground-water flow model parameters was applied to the regional aquifer underlying the eastern Snake River Plain, Idaho. The technique uses a computer program to simulate two-dimensional, steady-state ground-water flow. Hydrologic data for the 1980 water year were used to calculate recharge rates, boundary fluxes, and spring discharges. Ground-water use was estimated from irrigated land maps and crop consumptive-use figures. These estimates of ground-water withdrawal, recharge rates, and boundary flux, along with leakance, were used as known values in the model calibration of transmissivity. Leakance values were adjusted between regression solutions by comparing model-calculated to measured spring discharges. In other simulations, recharge and leakance also were calibrated as prior-information regression parameters, which limits the variation of these parameters using a normalized standard error of estimate. Results from a best-fit model indicate a wide areal range in transmissivity from about 0.05 to 44 feet squared per second and in leakance from about 2.2x10 -9 to 6.0 x 10 -8 feet per second per foot. Along with parameter values, model statistics also were calculated, including the coefficient of correlation between calculated and observed head (0.996), the standard error of the estimates for head (40 feet), and the parameter coefficients of variation (about 10-40 percent). Additional boundary flux was added in some areas during calibration to achieve proper fit to ground-water flow directions. Model fit improved significantly when areas that violated model assumptions were removed. It also improved slightly when y-direction (northwest-southeast) transmissivity values were larger than x-direction (northeast-southwest) transmissivity values. The model was most sensitive to changes in recharge, and in some areas, to changes in transmissivity, particularly near the spring discharge area from Milner Dam to King Hill.

Water Supply Paper↗

USGS2016

Latest Miocene-earliest Pliocene evolution of the ancestral Rio Grande at the Española-San Luis Basin boundary, northern New Mexico

We use stratigraphic relations, paleoflow data, and 40 Ar/ 39 Ar dating to interpret net aggradation, punctuated by at least two minor incisional events, along part of the upper ancestral Rio Grande fluvial system between 5.5 and 4.5 Ma (in northern New Mexico). The studied fluvial deposits, which we informally call the Sandlin unit of the Santa Fe Group, overlie a structural high between the San Luis and Española Basins. The Sandlin unit was deposited by two merging, west- to southwest-flowing, ancestral Rio Grande tributaries respectively sourced in the central Taos Mountains and southern Taos Mountains-northeastern Picuris Mountains. The river confluence progressively shifted southwestward (downstream) with time, and the integrated river (ancestral Rio Grande) flowed southwards into the Española Basin to merge with the ancestral Rio Chama. Just prior to the end of the Miocene, this fluvial system was incised in the southern part of the study area (resulting in an approximately 4–7 km wide paleovalley), and had sufficient competency to transport cobbles and boulders. Sometime between emplacement of two basalt flows dated at 5.54± 0.38 Ma and 4.82±0.20 Ma (groundmass 40 Ar/ 39 Ar ages), this fluvial system deposited 10–12 m of sandier sediment (lower Sandlin subunit) preserved in the northern part of this paleovalley. The fluvial system widened between 4.82±0.20 and 4.50±0.07 Ma, depositing coarse sand and fine gravel up to 14 km north of the present-day Rio Grande. This 10–25 m-thick sediment package (upper Sandlin unit) buried earlier south- to southeast-trending paleovalleys (500–800 m wide) inferred from aeromagnetic data. Two brief incisional events are recognized. The first was caused by the 4.82±0.20 Ma basalt flow impounding south-flowing paleodrainages, and the second occurred shortly after emplacement of a 4.69±0.09 Ma basalt flow in the northern study area. Drivers responsible for Sandlin unit aggradation may include climate-modulated hydrologic factors (i.e., variable sediment supply and water discharge) or a reduction of eastward tilt rates of the southern San Luis Basin half graben. If regional in extent, these phenomena could also have promoted fluvial spillover that occurred in the southern Albuquerque Basin at about 6–5 Ma, resulting in southward expansion of the Rio Grande to southern New Mexico.

New Mexico↗

USGS1990

Effect of faults on fluid flow and chloride contamination in a carbonate aquifer system

A unified, multidiscipline hypothesis is proposed to explain the anomalous pattern by which chloride has been found in water of the Upper Floridan aquifer in Brunswick, Glynn County, Georgia. Analyses of geophysical, hydraulic, water chemistry, and aquifer test data using the equivalent porous medium (EPM) approach are used to support the hypothesis and to improve further the understanding of the fracture-flow system in this area. Using the data presented herein we show that: (1) four major northeast-southwest trending faults, capable of affecting the flow system of the Upper Floridan aquifer, can be inferred from structural analysis of geophysical data and from regional fault patterns; (2) the proposed faults account for the anomalous northeastward elongation of the potentiometric surface of the Upper Floridan aquifer; (3) the faults breach the nearly impermeable units that confine the Upper Floridan aquifer from below, allowing substantial quantities of water to leak vertically upward; as a result, aquifer transmissivity need not be excessively large (as previously reported) to sustain the heavy, long-term pumpage at Brunswick without developing a steep cone of depression in the potentiometric surface; (4) increased fracturing at the intersection of the faults enhances the development of conduits that allow the upward migration of high-chloride water in response to pumping from the Upper Floridan aquifer; and (5) the anomalous movement of the chloride plume is almost entirely controlled by the faults.

Georgia↗

USGS2010

Groundwater flow systems at the Nevada Test Site, Nevada: A synthesis of potentiometric contours, hydrostratigraphy, and geologic structures

Contaminants introduced into the subsurface of the Nevada Test Site by underground nuclear testing are of concern to the U.S. Department of Energy and regulators responsible for protecting human health and safety. The potential for contaminant movement away from the underground test areas and into the accessible environment is greatest by groundwater transport. The primary hydrologic control on this transport is evaluated and examined through a series of contour maps developed to represent the hydraulic-head distribution within each of the major aquifers underlying the area. Aquifers were identified and their extents delineated by merging and analyzing multiple hydrostratigraphic framework models developed by other investigators from existing geologic information. A map of the hydraulic-head distribution in each major aquifer was developed from a detailed evaluation and assessment of available water-level measurements. Multiple spreadsheets that accompany this report provide pertinent water-level and geologic data by well or drill hole. Aquifers are mapped and discussed in general terms as being one of two types: alluvial–volcanic, or carbonate. Both aquifer types are subdivided and mapped as independent regional and local aquifers, based on the continuity of their component rock. Groundwater-flow directions, approximated from potentiometric contours that were developed from the hydraulic-head distribution, are indicated on the maps and discussed for each of the regional aquifers and for selected local aquifers. Hydraulic heads vary across the study area and are interpreted to range in altitude from greater than 5,000 feet in a regional alluvial–volcanic aquifer beneath a recharge area in the northern part of the study area to less than 2,300 feet in regional alluvial–volcanic and carbonate aquifers in the southwestern part of the study area. Flow directions throughout the study area are dominantly south-southwest with some local deviations. Vertical hydraulic gradients between aquifer types are downward throughout most of the study area; however, flow from the alluvial–volcanic aquifer into the underlying carbonate aquifer, where both aquifers are present, is believed to be minor because of an intervening confining unit. Limited exchange of water between aquifer types occurs by diffuse flow through the confining unit, by focused flow along fault planes, or by direct flow where the confining unit is locally absent. Interflow between regional aquifers is evaluated and mapped to define major flow paths. These flow paths delineate tributary flow systems, which converge to form intermediate and regional flow systems. The implications of these flow systems in controlling transport of radionuclides away from the underground test areas at the Nevada Test Site are briefly discussed. Additionally, uncertainties in the delineation of aquifers, the development of potentiometric contours, and the identification of flow systems are identified and evaluated. Eleven tributary flow systems and three larger flow systems are mapped in the Nevada Test Site area. Flow systems within the alluvial–volcanic aquifer dominate the western half of the study area, whereas flow systems within the carbonate aquifer are most prevalent in the southeastern half of the study area. Most of the flow in the regional alluvial–volcanic aquifer that moves through the underground testing area on Pahute Mesa is discharged to the land surface at springs and seeps in Oasis Valley. Flow in the regional carbonate aquifer is internally compartmentalized by major geologic structures, primarily thrust faults, which constrain flow into separate corridors. Contaminants that reach the regional carbonate aquifer from testing areas in Yucca and Frenchman Flats flow toward downgradient discharge areas through the Alkali Flat–Furnace Creek Ranch or Ash Meadows flow systems and their tributaries.

Nevada↗

USGS1996

Hydrogeology and simulation of ground-water flow, Picatinny Arsenal and vicinity, Morris County, New Jersey

Ground-water flow in glacial sediments and bedrock at Picatinny Arsenal, N.J., was simulated by use of a three-dimensional finite-difference ground- water-flow model. The modeled area includes a 4.3-square-mile area that extends from Picatinny Lake to the Rockaway River. Most of the study area is bounded by the natural hydrologic boundaries of the ground-water system. eophysical logs, lithologic logs, particle-size data, and core data from selected wells and surface geophysical data were analyzed to define the hydrogeologic framework. Hydrogeologic sections and thickness maps define six permeable and three low-permeability layers that are represented in the model as aquifers and confining units, respectively. Hydrologic data incorporated in the model include a rate of recharge from precipitation of 22 inches per year, estimated from long-term precipitation records and estimates of evapotranspiration. Additional recharge from infiltration along valleys was estimated from measured discharge of springs along the adjacent valley walls and from estimates of runoff from upland drainage that flows to the valley floor. Horizontal and vertical hydraulic conductivities of permeable and low-permeability layers were estimated from examination of aquifer-test data, gamma-ray logs, borehole cuttings, and previously published data. Horizontal hydraulic conductivities in glacial sediments range from 10 to 380 feet per day. Vertical hydraulic conductivities of the low-permeability layers range from 0.01 to 0.7 feet per day. The model was calibrated by simulating steady-state conditions during 1989-93 and by closely matching simulated and measured ground-water levels, vertical ground-water-head differences, and streamflow gain and loss. Simulated steady-state potentiometric- surface maps produced for the six permeable layers indicate that ground water in the unconfined material within Picatinny Arsenal flows predominantly toward the center of the valley, where it discharges to Green Pond Brook. Beneath the upper confining unit, ground water flows southwestward, down the valley. Between First Street and Farley Avenue, the upper confining unit pinches out near the valley walls, resulting in a major input of water to, and causing a local potentiometric high in, the underlying aquifer layers. Ground-water-flow directions southwest of the southern arsenal boundary are predominantly to the Rockaway River.

New Jersey↗

USGS2003

Ground-water resources of Saipan, Commonwealth of the Northern Mariana Islands

Saipan has an area of 48 mi 2 and is the largest of the 14 islands in the Commonwealth of the Northern Mariana Islands (CNMI). The island is formed by volcanic rocks overlain by younger limestones. The island is situated in the western Pacific Ocean at latitude 15 o 12'N and longitude 145 o 45'E, about 3,740 mi west-southwest of Honolulu and midway between Japan and New Guinea (fig. 1). The climate on Saipan is classified as tropical marine with an average temperature of 80 o F. The natural beauty of the island and surrounding waters are the basis for a growing tourist-based economy. The resulting rapid development and increases in resident and tourist populations have added stresses to the island's limited water supplies. Freshwater resources on Saipan are not readily observable because, aside from the abundant rainfall, most freshwater occurs as ground water. Fresh ground water is found in aquifers composed mainly of fragmental limestones. About 90 percent of the municipal water supply comes from 140 shallow wells that withdraw about 11 Mgal/d. The chloride concentration of water withdrawn from production wells ranges from less than 100 mg/L for wells in the Akgak and Capital Hill well fields, to over 2,000 mg/L from wells in the Puerto Rico, Maui IV, and Marpi Quarry well fields. The chloride concentrations and rates of ground-water production are not currently adequate for providing island residents with a potable 24-hour water supply and future demands are expected to be higher. To better understand the ground-water resources of the island, and water resources on tropical islands in general, the U.S. Geological Survey (USGS) entered into a cooperative program with the Commonwealth Utilities Corporation (CUC). The objective of the program, initiated in 1989, is to assess the ground-water resources of Saipan and to make hydrologic information available to the CUC in support of their ongoing efforts to improve the quality and quantity of the municipal water supply. This report presents some of the results of the program including descriptions of (1) the geography and geology, (2) the occurrence of fresh ground water in permeable limestones that extend to some distance below sea level where water-level elevation is affected by ocean tides (coastal aquifers) and in limestones that overlie volcanic basement rocks above sea level (high-level aquifers), (3) the water-table configuration and directions of ground-water flow, and (4) the rainfall, ground-water withdrawal, and chloride concentrations in well water. Also described is the relation of the changes in water-table elevations to changes in sea level, rainfall, and ground-water withdrawal.

Saipan↗

USGS1970

Taunton River basin

The Taunton River, emptying into an arm of Narragansett Bay at Fall River, drains 528 square miles of interior southeastern Massachusetts. The Taunton River basin is separated from the basins of short streams draining to the coast by low divides on the east, south, and southwest. On the west and north, the basin is bordered by the Ten Mile, Charles, Neponset, and Weymouth River basins. Principal tributaries of the lower Taunton River are Segreganset, Threemile, Mill, Assonet, Nemasket, and Winnetuxet Rivers. The upper part of the basin is drained by the Canoe, Wading, and Rumford Rivers which empty into Mill and Threemile Rivers and by the Matfield and Town Rivers which unite to form the Taunton River. This report presents in tabular form selected records of wells, test wells, and borings collected during a study of the basin from 1966 to 1968 in cooperation with the Massachusetts Water Resources Commission, and during earlier studies. This report is released in order to make available to the public and to local, state, and federal agencies basic ground-water information that may aid in planning water-resources development. Basic records contained in this report will complement an interpretative report on the Taunton River basin to be released at a later date.

Massachusetts↗

USGS1996

Shallow subsurface geology of part of the Savannah River alluvial valley in the upper Coastal Plain of Georgia and South Carolina

The depth to which Coastal Plain rivers incise underlying formations is an important control on local and regional hydrologic flow systems. In order to clarify these stream/aquifer relations, a better understanding of the shallow subsurface geology of the Savannah River was necessary. To accomplish this, three drillhole transects were completed across a part of the Savannah River alluvial valley in September 1993, and five geologic sections were constructed from the data. The alluvium is coarser, more angular, and more poorly sorted than the underlying formations, and lithologic differences between the strata are readily apparent, especially in areas where the underlying strata are of marine origin. Inspection of the transects indicates an asymmetry to both the alluvial terrace complex and the underlying bedrock strath. The alluvium thins in a coastward direction; and similarly, bulk-grain size diminishes in a downstream direction. This phenomenon has remained constant over time and is most likely a function of the change in slope which occurs when the river traverses the Fall Line north of the study area. The maximum thickness of the alluvial valley fill is 50 ft. The elevation of the unconformity between the alluvium and the underlying formation is far below the lowest elevation of the modern-day thalweg, indicating that the alluvial system has aggraded to form the modern-day Savannah River Valley. Formerly, the Savannah River was located immediately adjacent to and east of the modern floodplain when the river valley was formed by a cyclic pattern of infilling and subsequent entrenchment that gave rise to an irregular bedrock surface beneath the depositional terrace system. After this depositional period, the river migrated to the southwest and began a period of downcutting that ended with the formation of the unconformity (erosional terrace) that lies some 45 ft. beneath the modern-day river. The protracted southwestward migration of the river system is perhaps the best indication that pre-historic tectonism exerts an influence on the modern-day alluvial system.

Southeastern Geology↗

USGS2019

Evaluation of chemical and hydrologic processes in the eastern Snake River Plain Aquifer based on results from geochemical modeling, Idaho National Laboratory, eastern Idaho

Nuclear research activities at the U.S. Department of Energy (DOE) Idaho National Laboratory (INL) produced liquid and solid chemical and radiochemical wastes that were disposed to the subsurface resulting in detectable concentrations of some waste constituents in the eastern Snake River Plain (ESRP) aquifer. These waste constituents may affect the water quality of the aquifer and may pose risks to the eventual users of the aquifer water. To understand these risks to water quality the U.S. Geological Survey, in cooperation with the DOE, conducted geochemical mass-balance modeling of the ESRP aquifer to improve the understanding of chemical reactions, sources of recharge, mixing of water, and groundwater flow directions in the shallow (upper 250 feet) aquifer at the INL. Modeling was conducted using the water chemistry of 127 water samples collected from sites at and near the INL. Water samples were collected between 1952 and 2017 with most of the samples collected during the mid-1990s. Geochemistry and isotopic data used in geochemical modeling consisted of dissolved oxygen, carbon dioxide, major ions, silica, aluminum, iron, and the stable isotope ratios of hydrogen, oxygen, and carbon. Geochemical modeling results indicated that the primary chemical reactions in the aquifer were precipitation of calcite and dissolution of plagioclase (An 60 ) and basalt volcanic glass. Secondary minerals other than calcite included calcium montmorillonite and goethite. Reverse cation exchange, consisting of sodium exchanging for calcium on clay minerals, occurred near site facilities where large amounts of sodium were released to the ESRP aquifer in wastewater discharge. Reverse cation exchange acted to retard the movement of wastewater-derived sodium in the aquifer. Regional groundwater inflow was the primary source of recharge to the aquifer underlying the Northeast and Southeast INL Areas. Birch Creek (BC), the Big Lost River (BLR), and groundwater from BC valley provided recharge to the North INL Area, and the BLR and groundwater from BC and Little Lost River (LLR) valleys provided recharge to the Central INL Area. The BLR, groundwater from the BLR and LLR valleys and the Lost River Range, and precipitation provided recharge to the Northwest and Southwest INL Areas. The primary source of recharge west and southwest of the INL was groundwater inflow from BLR valley. Upwelling geothermal water was a small source of recharge at two wells. Aquifer recharge from surface water in the northern, central, and western parts of the INL indicated that the aquifer in these areas was a dynamic, open system, whereas the aquifer in the eastern part of the INL, which receives little recharge from surface water, was a relatively static and closed system. Sources of recharge identified from isotope ratios and geochemical modeling (major ion concentrations) were nearly identical for the North, Northeast, Southeast, and Central INL Areas, which indicated that both methods probably accurately identified the sources of recharge in these areas. Conversely, isotope ratios indicated that the BLR and groundwater from the LLR valley provided most recharge to the western parts of the Northwest and Southwest INL Areas, whereas geochemical modeling results indicated a smaller area of recharge from the BLR and groundwater from the LLR valley, a larger area of recharge from the Lost River Range, and recharge of groundwater from the BLR valley that extended to the west INL boundary. The results from geochemical modeling probably were more accurate because major ion concentrations, but not isotope ratios, were available to characterize groundwater from the BLR valley and the Lost River Range. Sources of recharge identified with a groundwater flow model (using particle tracking) and geochemical modeling were similar for the Northeast and Southeast INL Areas. However, differences between the models were that the geochemical model represented (1) recharge of groundwater from the Lost River Range in the western part of the INL, whereas the flow model did not, (2) recharge of groundwater from the BC and BLR valleys extending farther south and east, respectively, than the flow model, and (3) more recharge from the BLR in the Southwest INL Area than the flow model. Mixing of aquifer water beneath the INL included (1) mixing of regional groundwater and water from the BC valley in the Northeast and Southeast INL Areas and (2) mixing of surface water (primarily from the BLR) and groundwater across much of the North, Central, Northwest, and Southwest INL Areas. Localized recharge from precipitation mixed with groundwater in the Northwest and Southwest INL Areas, and localized upwelling geothermal water mixed with groundwater in the Central and Northeast INL Areas. Flow directions of regional groundwater were south in the eastern part of the INL and south-southwest at downgradient locations. Groundwater from the BC and LLR valleys initially flowed southeast before changing to south-southwest flow directions that paralleled regional groundwater, and groundwater from the BLR valley initially flowed south before changing to a southsouthwest direction. Wastewater-contaminated groundwater flowed south from the Idaho Nuclear Technology and Engineering Center (INTEC) infiltration ponds in a narrow plume, with the percentage of wastewater in groundwater decreasing due to dilution, dispersion, and (or) degradation from about 60‒80 percent wastewater 0.7‒0.8 mile (mi) south of the INTEC infiltration ponds to about 1.4 percent wastewater about 15.5 mi south of the INTEC infiltration ponds. Wastewater contaminated groundwater flowed southeast and then southwest from the Naval Reactors Facility industrial waste ditch, with the percentage of wastewater in groundwater decreasing from about 100 percent wastewater adjacent to the waste ditch to about 2 percent wastewater about 0.6 mi south of the waste ditch.

Idaho↗