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USGS2002

Ground-water resources of the Clifton Park area, Saratoga County, New York

Ground water is the sole source of public water supply for Clifton Park, a growing suburban community north of Albany, New York. Increasing water demand, coupled with concerns over ground-water quantity and quality, led the Clifton Park Water Authority in 1995 to initiate a cooperative study with the U.S. Geological Survey to update and refine the understanding of ground-water resources in the area. Ground-water resources are largely associated with three aquifers in the eastern half of the area. These aquifers overlie or encompass the Colonie Channel, a north-south-oriented bedrock channel that is filled primarily with lacustrine glacial deposits. The three aquifers are: (1) an unconfined lacustrine sand aquifer, (2) the Colonie Channel aquifer, which is confined within the deepest parts of the channel and variably confined and unconfined within the shallower, peripheral channel areas, and (3) an unconfined alluvial aquifer beneath the Mohawk River flood plain, which represents the southern limit of the study area. The lacustrine sand aquifer has little potential for large-scale withdrawals because it is predominantly fine grained and is susceptible to contamination from human activities at land surface. Water from this aquifer can, however, recharge the underlying peripheral parts of the Colonie Channel aquifer where hydraulic connections are present. The Colonie Channel aquifer consists of thin sand and gravel and (or) shallow, fractured bedrock over much of the channel area; discontinuous deposits of thicker (more than 20 feet) sand and gravel are common in the peripheral channel areas. The deepest, or central, channel area of this aquifer is isolated from the overlying lacustrine sand aquifer by a continuous lacustrine silt and clay unit, which is the primary channel-fill deposit. The most productive areas of the Colonie Channel aquifer are typically the shallow peripheral areas, where conditions range from unconfined to confined. The most productive aquifer within the area is the alluvial aquifer, which is sustained to an unknown extent by induced infiltration of Mohawk River water. The chemical composition of ground water within the Clifton Park area varies widely in response to hydrogeologic setting, pumpage, and contamination from human activities. These chemical differences can be used to deduce ground-water flow paths within and between the unconfined and confined areas of the aquifer system. Six water types are defined; three are naturally occurring and three are the result of human activities. Precipitation that infiltrates the land surface is the sole source of recharge to the lacustrine sand aquifer; precipitation also recharges the alluvial aquifer and unconfined parts of the Colonie Channel aquifer. Ground-water withdrawals from confined or unconfined peripheral areas of the Colonie Channel aquifer induce flow from recharge areas, from the underlying bedrock, or from other confined aquifer areas. The rate of recharge to the confined central area of the Colonie Channel aquifer appears to be low. Potentiometric levels as much as 100 feet below water-table levels in the overlying lacustrine sand aquifer indicate two large depressions in the potentiometric surface; these depressions indicate that withdrawals from this aquifer have cumulatively exceeded the recharge rates. Localized recharge of the central channel area apparently occurs from two peripheral channel areas that are characterized by zones of elevated water levels and (or) by water chemistry that differs from those within the central channel area. Recharge from, or hydraulic connection with, adjoining segments of the Colonie Channel aquifer to the north and south is likely, but the potential for significant recharge is low because the aquifer is thin and poorly permeable.

New York↗

USGS2004

Updated computations and estimates of streamflows tributary to Carson Valley, Douglas County, Nevada, and Alpine County, California, 1990-2002

Rapid population growth in Carson Valley has caused concern over the continued availability of water resources to sustain future growth. The U.S. Geological Survey, in cooperation with Douglas County, began a study to update estimates of water-budget components in Carson Valley for current climatic conditions. Data collected at 19 sites included 9 continuous records of tributary streamflows, 1 continuous record of outflow from the valley, and 408 measurements of 10 perennially flowing but ungaged drainages. These data were compiled and analyzed to provide updated computations and estimates of streamflows tributary to Carson Valley, 1990-2002. Mean monthly and annual flows were computed from continuous records for the period 1990-2002 for five streams, and for the period available, 1990-97, for four streams. Daily mean flow from ungaged drainages was estimated using multi-variate regressions of individual discharge measurements against measured flow at selected continuous gages. From the estimated daily mean flows, monthly and annual mean flows were calculated from 1990 to 2002. These values were used to compute estimates of mean monthly and annual flows for the ungaged perennial drainages. Using the computed and estimated mean annual flows, annual unit-area runoff was computed for the perennial drainages, which ranged from 0.30 to 2.02 feet. For the period 1990-2002, estimated inflow of perennial streams tributary to Carson Valley totaled about 25,900 acre-feet per year. Inflow computed from gaged perennial drainages totaled 10,300 acre-feet per year, and estimated inflow from ungaged perennial drainages totaled 15,600 acre-feet per year. The annual flow of perennial streams ranges from 4,210 acre-feet at Clear Creek to 450 acre-feet at Stutler Canyon Creek. Differences in unit-area runoff and in the seasonal timing of flow likely are caused by differences in geologic setting, altitude, slope, or aspect of the individual drainages. The remaining drainages are ephemeral and supply inflow to the valley floor only during spring runoff in wet years or during large precipitation events. Annual unit-area runoff for the perennial drainages was used to estimate inflow from ephemeral drainages totaling 11,700 acre-feet per year. The totaled estimate of perennial and ephemeral tributary inflows to Carson Valley is 37,600 acre-feet per year. Gaged perennial inflow is 27 percent of the total, ungaged perennial inflow is 42 percent, and ephemeral inflow is 31 percent. The estimate is from 50 to 60 percent greater than three previous estimates, one made for a larger area and similar to two other estimates made for larger areas. The combined uncertainty of the estimates totaled about 33 percent of the total inflow or about 12,000 acre-feet per year.

Scientific Investigations Report↗

USGS2020

Quantifying drought’s influence on moist soil seed vegetation in California’s Central Valley through time-series remote sensing

Californias Central Valley, USA is a critical component of the Pacific Flyway despite loss of more than 90% of its wetlands. Moist soil seed (MSS) wetland plants are now produced by mimicking seasonal flooding in managed wetlands to provide an essential food resource for waterfowl. Managers need MSS plant area and productivity estimates to support waterfowl conservation, yet this remains unknown at the landscape scale. Also the effects of recent drought on MSS plants have not been quantified. We generated Landsat-derived estimates of extents and productivity (seed yield or its proxy, the green chlorophyll index) of major MSS plants including watergrass (Echinochloa crusgalli) and smartweed (Polygonum spp.) (WGSW), and swamp timothy (Crypsis schoenoides) (ST) in all Central Valley managed wetlands from 20072017. We tested the effects of water year, land ownership and region on plant area and productivity with a multifactor nested analysis of variance. For the San Joaquin Valley we explored the association between water year and water supply, and we developed metrics to support management decisions. MSS plant area maps were based on a support vector machine classification of Landsat phenology metrics (2017 map overall accuracy: 89%). ST productivity maps were created with a linear regression model of seed yield (n=68, R2 = 0.53, normalized RMSE = 10.5%). The Central Valley-wide estimated area for ST in 2017 was 32,369 ha 2,524 ha (95% C.I.), and 13,012 ha 1,384 ha for WGSW. Mean ST seed yield ranged from 577 kg/ha in the Delta Basin to 365 kg/ha in the San Joaquin Basin. WGSW area and ST seed yield decreased while ST area increased in critical drought years compared to normal water years (Scheffes test, p<0.05). Greatest ST area increases occurred in the Sacramento Valley (~75%). Voluntary water deliveries increased in normal water years, and ST seed yield increased with water supply. Z-scores of ST seed yield can be used to evaluate wetland performance and aid resource allocation decisions. Updated maps will support habitat monitoring, conservation planning and water management in future years, which are likely to face greater uncertainty in water availability with climate change.

California↗

USGS2014

Progress in data collection and dissemination in water resources – 1974-2014

In the 50 years since the founding of the American Water Resources Association (AWRA), there has been tremendous and likely unforeseen progress in water-re- sources data collection and dissemination. Langford and Doyel (1974) (henceforth L&D) described progress during the decade following the founding of AWRA, and focused their description around seven topics. L&D described the changes as being “more philosophical than technical,” and noted the importance to the water-resources com- munity of the more than 30 Federal Acts or Amendments enacted in the decade. The purpose of this article is to provide an update to L&D by reviewing L&D’s predictions of anticipated changes in water resources data collection and dissemi-nation, providing an overview of some of the drivers of change in the water-resources community in the last 40 years, identifying some key advances in water-resources data collection and dissemination since 1974, and out-lining some important near-term challenges. The overview is necessarily incomplete, but represents one perspective based on years of collaboration throughout the water-resources community.

Water Resources Impact↗

USGS2017

Fena Valley Reservoir watershed and water-balance model updates and expansion of watershed modeling to southern Guam

In 2014, the U.S. Geological Survey, in cooperation with the U.S. Department of Defense’s Strategic Environmental Research and Development Program, initiated a project to evaluate the potential impacts of projected climate-change on Department of Defense installations that rely on Guam’s water resources. A major task of that project was to develop a watershed model of southern Guam and a water-balance model for the Fena Valley Reservoir. The southern Guam watershed model provides a physically based tool to estimate surface-water availability in southern Guam. The U.S. Geological Survey’s Precipitation Runoff Modeling System, PRMS-IV, was used to construct the watershed model. The PRMS-IV code simulates different parts of the hydrologic cycle based on a set of user-defined modules. The southern Guam watershed model was constructed by updating a watershed model for the Fena Valley watersheds, and expanding the modeled area to include all of southern Guam. The Fena Valley watershed model was combined with a previously developed, but recently updated and recalibrated Fena Valley Reservoir water-balance model. Two important surface-water resources for the U.S. Navy and the citizens of Guam were modeled in this study; the extended model now includes the Ugum River watershed and improves upon the previous model of the Fena Valley watersheds. Surface water from the Ugum River watershed is diverted and treated for drinking water, and the Fena Valley watersheds feed the largest surface-water reservoir on Guam. The southern Guam watershed model performed “very good,” according to the criteria of Moriasi and others (2007), in the Ugum River watershed above Talofofo Falls with monthly Nash-Sutcliffe efficiency statistic values of 0.97 for the calibration period and 0.93 for the verification period (a value of 1.0 represents perfect model fit). In the Fena Valley watershed, monthly simulated streamflow volumes from the watershed model compared reasonably well with the measured values for the gaging stations on the Almagosa, Maulap, and Imong Rivers—tributaries to the Fena Valley Reservoir—with Nash-Sutcliffe efficiency values of 0.87 or higher. The southern Guam watershed model simulated the total volume of the critical dry season (January to May) streamflow for the entire simulation period within –0.54 percent at the Almagosa River, within 6.39 percent at the Maulap River, and within 6.06 percent at the Imong River. The recalibrated water-balance model of the Fena Valley Reservoir generally simulated monthly reservoir storage volume with reasonable accuracy. For the calibration and verification periods, errors in end-of-month reservoir-storage volume ranged from 6.04 percent (284.6 acre-feet or 92.7 million gallons) to –5.70 percent (–240.8 acre-feet or –78.5 million gallons). Monthly simulation bias ranged from –0.48 percent for the calibration period to 0.87 percent for the verification period; relative error ranged from –0.60 to 0.88 percent for the calibration and verification periods, respectively. The small bias indicated that the model did not consistently overestimate or underestimate reservoir storage volume. In the entirety of southern Guam, the watershed model has a “satisfactory” to “very good” rating when simulating monthly mean streamflow for all but one of the gaged watersheds during the verification period. The southern Guam watershed model uses a more sophisticated climate-distribution scheme than the older model to make use of the sparse climate data, as well as includes updated land-cover parameters and the capability to simulate closed depression areas. The new Fena Valley Reservoir water-balance model is useful as an updated tool to forecast short-term changes in the surface-water resources of Guam. Furthermore, the now spatially complete southern Guam watershed model can be used to evaluate changes in streamflow and recharge owing to climate or land-cover changes. These are substantial improvements to the previous models of the Fena Valley watershed and Reservoir. Datasets associated with this report are available as a U.S. Geological Survey data release (Rosa and Hay, 2017; DOI:10.5066/F7HH6HV4).

Scientific Investigations Report↗

USGS1966

Ground water in the Cimarron River basin: New Mexico, Colorado, Kansas, and Oklahoma

This report on ground water in the Cimarron River basin was prepared by the Water Resources Division of the U.S. Geological Survey at the request of the U.S. Corps of Engineers, Tulsa District, for inclusion in the Corps' overall report on the water resources of the basin. The report is an updating of the Cimarron Basin part of the report on the Arkansas, White, and Red River basins (Lohman and Burtis, 1953a) and includes more recently published data, as well as unpublished data in the files of the Geological Survey. These data are compiled by district offices of the Geological Survey in each State in cooperation with State and local agencies and with other Federal agencies. No new data were collected as a part of this investigation. The report is primarily a map presentation, and the text is intended mainly to clarify and supplement the maps and to make them more understandable and usable. The report also presents some of the ground-water problems--both present and potential--and suggests some partial solutions. As the maps and text are of necessity highly generalized, the reader is referred to the more detailed reports for more precise information.

Colorado, Kansas, New Mexico, Oklahoma↗

USGS2015

Chemical considerations for an updated National assessment of brackish groundwater resources

Brackish groundwater (BGW) is increasingly used for water supplies where fresh water is scarce, but the distribution and availability of such resources have not been characterized at the national scale in the United States since the 1960s. Apart from its distribution and accessibility, BGW usability is a function of the chemical requirements of the intended use, chemical characteristics of the resource, and treatment options to make the resource compatible with the use. Here, we discuss relations between these three chemical factors using national-scale examples and local case studies. In a preliminary compilation of BGW data in the United States, five water types accounted for the major-ion composition of 70% of samples. PHREEQC calculations indicate that 57–77% of samples were oversaturated with respect to barite, calcite, or chalcedony. In the study, 5–14% of samples had concentrations of arsenic, fluoride, nitrate, or uranium that exceeded drinking-water standards. In case studies of the potential use of BGW for drinking water, irrigation, and hydraulic fracturing, PHREEQC simulations of a hypothetical treatment process resembling reverse osmosis (RO) showed that BGW had the potential to form various assemblages of mineral deposits (scale) during treatment that could adversely affect RO membranes. Speciation calculations showed that most boron in the irrigation example occurred as boric acid, which has relatively low removal efficiency by RO. Results of this preliminary study indicate that effective national or regional assessments of BGW resources should include geochemical characterizations that are guided in part by specific use and treatment requirements.

Groundwater↗

USGS1971

Index of surface-water records to September 30, 1970: Part 9. - Colorado River basin

This report lists the streamflow and reservoir stations in the Colorado River basin for which records have been or are to be published in reports of the Geological Survey for periods through September 30, 1970. It supersedes Geological Survey Circular 579. It was updated by personnel of the Data Reports Unit, Water Resources Division, Geological Survey.

Arizona, California, Colorado, Nevada, New Mexico,↗

USGS1971

Index of surface-water records to September 30, 1970; Part 10. - The Great Basin

This report lists the streamflow and reservoir stations in The Great Basin for which records have been or are to be published in reports of the Geological Survey for periods through September 30, 1970. It supersedes Geological Survey Circular 580. It was updated by personnel of the Data Reports Unit, Water Resources Division, Geological Survey.

California, Nevada, Oregon, Utah, Wyoming↗

USGS1971

Index of surface-water records to September 30, 1970: Part 13. - Snake River basin

This report lists the streamflow and reservoir stations in the Snake River basin for which records have been or are to be published in reports of the Geological Survey for periods through September 30, 1970. It supersedes Geological Survey Circular 583. It was updated by personnel of the Data Response Unit, Water Resources Division, Geological Survey.

Idaho, Nevada, Oregon, Utah, Washington, Wyoming↗

USGS2015

Progress toward a National Water Census

Increasing demand and competition for limited regional water resources make it difficult to ensure adequate water availability for both human and ecological needs now and into the future. Recognizing the need to improve the tools and information that are available to effectively evaluate water-resource availability, the U.S. Geological Survey (USGS) identified a National Water Census (NWC) as one of its six core science directions for the decade 2007–17. In 2009, the SECURE Water Act (Public Law 111–11) authorized the USGS to develop a national water availability and use assessment program that would update the most recent national assessment of the status of water resources in the United States as well as develop the science to improve forecasts of water availability and quality for future needs. By evaluating large-scale effects of changes in land use and land cover, water use, and climate on occurrence and distribution of water, water quality, and human and aquatic-ecosystem health, the NWC will also help to inform a broader initiative by the Department of the Interior, WaterSMART (Sustain and Manage America's Resources for Tomorrow), which provides multiagency funding to pursue a sustainable water supply for the Nation as directed under the SECURE Water Act. Through the NWC, the USGS actively engages Federal, regional, and local stakeholders to identify research priorities and leverages current studies and program activities to provide information that is relevant at both the national and regional scales.

Fact Sheet↗

USGS1974

Index of flood maps prepared by the U.S. Geological Survey through 1973

A listing is presented of flood maps prepared by the U.S. Geological Survey through 1973. Maps are listed by State and county and the list provides information on the type of flooding depicted and the reliability of the delineation. The list was prepared from a computer file, and an available program allows retrieval of data by land-line location, State and county, and Standard Metropolitan Statistical Area (SMSA). The file will be continuously updated.

Water-Resources Investigations Report↗

USGS1974

Index to maps of flood-prone areas in Indiana

A listing of flood maps for Indiana prepared by the U.S. Geological Survey through 1974 is presented by county. The list provides information on the type of flooding depicted and the reliability of the delineation. The list was prepared from a computer file, and an available program allows retrieval of data by land-line location, State and county, and Standard Metropolitan Statistical Area (SMSA). The file will be continuously updated.

Indiana↗

USGS2008

Inventory of Well Yields in Avery and Watauga Counties, North Carolina

More than 1,500 well records were compiled for Avery and Watauga Counties, North Carolina, as part of a study of ground-water resources. Wells in this area of the Blue Ridge Physiographic Province produce water from the fractured-bedrock aquifer. Prior to this study, only about 132 wells were included in the U.S. Geological Survey's National Water Information System, as a result of a study conducted during the late 1960s. The large number of additional well records provide a better data set to evaluate the ground-water resources. From the more recent well inventory conducted in 2007, the range of well yields in these two counties is from 0 to 400 gallons per minute. Total depth of the wells ranged from 20 to 1,204 feet below land surface, and depth to primary fracture zones ranged from 25 to 1,000 feet below land surface. In many rural areas of North Carolina (NC), ground water is the sole resource for drinking water. With increasing population, many more wells are being drilled, and information on this important resource needs to be updated. In February 2007, the U.S. Geological Survey (USGS) initiated a study in cooperation with the High Country Council of Governments, through a grant received by the North Carolina Rural Economic Development Center, to better quantify available ground-water resources in two rural counties (Avery and Watauga) in the northern North Carolina mountains. Many small towns in Avery and Watauga counties are dependent on wells from local fractured-bedrock aquifers, and local officials are concerned about the sustainability of the resource for support of economic development and population growth. In 2005, all residents in Avery County were served by ground-water resources, while 37 percent of the population in Watauga County was served by ground water (D.G. Smith, U.S. Geological Survey, written commun., 2007).

North Carolina↗

USGS2004

Water resources of the Tulalip Indian Reservation and adjacent area, Snohomish County, Washington, 2001-03

This study was undertaken to improve the understanding of water resources of the Tulalip Plateau area, with a primary emphasis on the Tulalip Indian Reservation, in order to address concerns of the Tulalip Tribes about the effects of current and future development, both on and off the Reservation, on their water resources. The drinking-water supply for the Reservation comes almost entirely from ground water, so increasing population will continue to put more pressure on this resource. The study evaluated the current state of ground- and surface-water resources and comparing results with those of studies in the 1970s and 1980s. The study included updating descriptions of the hydrologic framework and ground-water system, determining if discharge and base flow in streams and lake stage have changed significantly since the 1970s, and preparing new estimates of the water budget. The hydrogeologic framework was described using data collected from 255 wells, including their location and lithology. Data collected for the Reservation water budget included continuous and periodic streamflow measurements, micrometeorological data including daily precipitation, temperature, and solar radiation, water-use data, and atmospheric chloride deposition collected under both wet- and dry-deposition conditions to estimate ground-water recharge. The Tulalip Plateau is composed of unconsolidated sediments of Quaternary age that are mostly of glacial origin. There are three aquifers and two confining units as well as two smaller units that are only localized in extent. The Vashon recessional outwash (Qvr) is the smallest of the three aquifers and lies in the Marysville Trough on the eastern part of the study area. The primary aquifer in terms of use is the Vashon advance outwash (Qva). The Vashon till (Qvt) and the transitional beds (Qtb) act as confining units. The Vashon till overlies Qva and the transitional beds underlie Qva and separate it from the undifferentiated sediments (Qu), which are also a principal aquifer of the plateau. The undifferentiated-sediments aquifer is present throughout the entire study area, but is not well defined because few wells penetrate it. Ground water flows radially outward from the center of the Plateau in the Vashon advance outwash aquifer. Water levels fluctuate seasonally in all hydrogeologic units in response to changes in precipitation over the course of the year. However, water levels do not appear to have changed significantly over the long term. There was no statistically significant change between water levels measured in 72 wells in the early 1990s and 2001. Additionally, when a rank sum test was used to compare monthly water levels measured in 18 wells for this study with monthly water levels from the 1970s and 1980s, water levels increased in some wells, decreased in some, and did not change significantly in others. Ground water in the study area is recharged from precipitation that percolates down from the land surface. Average annual recharge, estimated using the chloride-mass-balance method, was 10.4 inches per year. Current streamflow conditions on the Reservation were defined by four continuous-record streamflow-gaging stations operated from April 2001 through March 2003 and monthly measurements of discharge at 12 periodic-measurement sites. Two continuous-record gaging stations (12157250 and 12158040) near the mouths of Mission and Tulalip Creeks, respectively, also were operated during water years 1975-77. Correlations of streamflow for Mission and Tulalip Creeks with the long-term record of streamflow at Mercer Creek (station 12120000) indicate no significant change in streamflow between the mid-1970s and 2001?03 in Mission and Tulalip Creeks. However, comparisons between the percentage of change in precipitation at the Everett precipitation station and percentages of change in streamflow at the Mercer, Mission, and Tulalip Creek gaging stations from the mid-1970s through 2001

Scientific Investigations Report↗

USGS2022

Groundwater budgets for the Big Lost River Basin, south-central Idaho, 2000–19

The Big Lost River Basin, located in parts of Butte and Custer Counties in south-central Idaho, supports the communities surrounding the cities of Arco, Leslie, Mackay, and Moore and provides for agricultural resources that depend on a sustainable supply of surface water from the Big Lost River and its tributaries and groundwater from an unconfined aquifer. The aquifer, situated in a structurally controlled intermontane valley, is composed of unconsolidated alluvium, consolidated sedimentary and volcanic rocks, and younger interbedded volcanic rocks. This report presents two separate groundwater budgets for the aquifer, one above and one below Mackay Dam, as well as a combined groundwater budget for the aquifer within the entire Big Lost River Basin. The budgets span a 20-year period (2000–19), characterizing average conditions, a dry year (2014), and a wet year (2017). The groundwater budgets will help address questions regarding the availability of groundwater supply in the Big Lost River Basin and inform future groundwater modeling. The Idaho Geological Survey has prepared the groundwater budgets as part of a larger hydrogeologic investigation completed by the U.S. Geological Survey and the Idaho Geological Survey in cooperation with the Idaho Department of Water Resources during 2018–21. Other reports describe the hydrogeologic framework and several streamflow-measurement events to evaluate gains and losses on the Big Lost River. Collectively, these reports provide an updated characterization of groundwater resources in the Big Lost River Basin which will help address water resources challenges. A groundwater budget is a conceptual and numerical accounting of inflow (recharge) to groundwater and outflow (discharge) from groundwater. The predominant sources of recharge to the aquifer include losing river reaches (33 percent), areal recharge (as precipitation less evapotranspiration and surface runoff, comprising about 23 percent of the total inflow), tributary canyon underflow from higher altitudes (20 percent), canal seepage (13 percent), recharge through applied irrigation on fields below the root zone and other minor sources (11 percent), and Mackay Reservoir seepage (less than 1 percent). The primary sources of discharge from the aquifer are groundwater pumpage to meet irrigation demand, domestic supply, and municipal supply (76 percent) and gaining river reaches (24 percent). The positive or negative difference between the sum of all inflows and outflows is regarded as the residual, representing the change in groundwater storage, groundwater outflow from the basin or subbasins, and uncertainty and errors in the budget. In the Big Lost River Basin, groundwater outflow is at the mouth of the basin below Arco into the eastern Snake River Plain aquifer. The total mean annual estimated recharge to the Big Lost River Basin was 439,100 acre-feet per year (acre-ft/yr; 607 cubic feet per second [ft 3 /s]) for 2000–19, 373,900 acre-ft/yr (516 ft 3 /s) in 2014, and 762,100 acre-ft/yr (1,053 ft 3 /s) in 2017. The mean annual estimated groundwater discharge from the aquifer was about 112,300 acre-ft/yr (155 ft 3 /s) for 2000–19, 153,500 acre-ft/yr (212 ft 3 /s) in 2014, and 53,400 acre-ft/yr (74 ft 3 /s) in 2017. The estimated mean annual groundwater residual was 326,800 acre-ft/yr (451 ft 3 /s) for 2000–19, 220,400 acre-ft/yr (304 ft 3 /s) in 2014, and 708,700 acre-ft/yr (979 ft 3 /s) in 2017. The mean annual residual above Mackay Dam was 100,400 acre-ft/yr (2000-19), 96,700 acre-ft (2014), and 248,300 acre-ft (2017). The mean annual residual contribution below Mackay Dam, minus any groundwater-flow above Mackay Dam, was 226,400 acre-ft/yr (2000-19), 123,700 acre-ft (2014), and 460,400 acre-ft (2017). These results are highly sensitive to assumptions about certain budget inflow parameters. In particular, the magnitude of the budget residuals during especially dry and wet periods is amplified by the groundwater-budget terms tributary streamflow and tributary underflow that contribute appreciable recharge but also have high uncertainty. The results of the groundwater-budget evaluation describe an interconnected and complex hydrologic response throughout the basin to various climatic and water-use trends. The part of the basin above Mackay Dam typically has a positive groundwater residual derived from snowmelt recharge to tributary canyons and areal recharge in excess of groundwater pumpage for irrigation demand. This supply is used to meet irrigation demand above Mackay Dam and to provide for water supply below Mackay Dam. On average, groundwater inflow from above Mackay Dam to below Mackay Dam, assuming negligible reservoir storage effects, accounts for about 25 percent of the total groundwater recharge below Mackay Dam. Considerable recharge to groundwater below Mackay Dam occurs through seepage from the Big Lost River and canals and ditches. Most groundwater discharge from the aquifer is through irrigation pumping. The water supply below Mackay Dam is highly dependent on available upstream surface-water flows, the magnitude of the groundwater residual from above Mackay Dam, and annual variability in local groundwater conditions.

Idaho↗

USGS1998

Application of nonlinear-regression methods to a ground-water flow model of the Albuquerque Basin, New Mexico

This report documents the application of nonlinear-regression methods to a numerical model of ground-water flow in the Albuquerque Basin, New Mexico. In the Albuquerque Basin, ground water is the primary source for most water uses. Ground-water withdrawal has steadily increased since the 1940's, resulting in large declines in water levels in the Albuquerque area. A ground-water flow model was developed in 1994 and revised and updated in 1995 for the purpose of managing basin ground- water resources. In the work presented here, nonlinear-regression methods were applied to a modified version of the previous flow model. Goals of this work were to use regression methods to calibrate the model with each of six different configurations of the basin subsurface and to assess and compare optimal parameter estimates, model fit, and model error among the resulting calibrations. The Albuquerque Basin is one in a series of north trending structural basins within the Rio Grande Rift, a region of Cenozoic crustal extension. Mountains, uplifts, and fault zones bound the basin, and rock units within the basin include pre-Santa Fe Group deposits, Tertiary Santa Fe Group basin fill, and post-Santa Fe Group volcanics and sediments. The Santa Fe Group is greater than 14,000 feet (ft) thick in the central part of the basin. During deposition of the Santa Fe Group, crustal extension resulted in development of north trending normal faults with vertical displacements of as much as 30,000 ft. Ground-water flow in the Albuquerque Basin occurs primarily in the Santa Fe Group and post-Santa Fe Group deposits. Water flows between the ground-water system and surface-water bodies in the inner valley of the basin, where the Rio Grande, a network of interconnected canals and drains, and Cochiti Reservoir are located. Recharge to the ground-water flow system occurs as infiltration of precipitation along mountain fronts and infiltration of stream water along tributaries to the Rio Grande; subsurface flow from adjacent regions; irrigation and septic field seepage; and leakage through the Rio Grande, canal, and Cochiti Reservoir beds. Ground water is discharged from the basin by withdrawal; evapotranspiration; subsurface flow; and flow to the Rio Grande, canals, and drains. The transient, three-dimensional numerical model of ground-water flow to which nonlinear-regression methods were applied simulates flow in the Albuquerque Basin from 1900 to March 1995. Six different basin subsurface configurations are considered in the model. These configurations are designed to test the effects of (1) varying the simulated basin thickness, (2) including a hypothesized hydrogeologic unit with large hydraulic conductivity in the western part of the basin (the west basin high-K zone), and (3) substantially lowering the simulated hydraulic conductivity of a fault in the western part of the basin (the low-K fault zone). The model with each of the subsurface configurations was calibrated using a nonlinear least- squares regression technique. The calibration data set includes 802 hydraulic-head measurements that provide broad spatial and temporal coverage of basin conditions, and one measurement of net flow from the Rio Grande and drains to the ground-water system in the Albuquerque area. Data are weighted on the basis of estimates of the standard deviations of measurement errors. The 10 to 12 parameters to which the calibration data as a whole are generally most sensitive were estimated by nonlinear regression, whereas the remaining model parameter values were specified. Results of model calibration indicate that the optimal parameter estimates as a whole are most reasonable in calibrations of the model with with configurations 3 (which contains 1,600-ft-thick basin deposits and the west basin high-K zone), 4 (which contains 5,000-ft-thick basin de

New Mexico↗

USGS2016

Streamflow characteristics based on data through water year 2009 for selected streamflow-gaging stations in or near Montana: Chapter E in Montana StreamStats

Chapter E of this Scientific Investigations Report documents results from a study by the U.S. Geological Survey, in cooperation with the Montana Department of Environmental Quality and the Montana Department of Natural Resources and Conservation, to provide an update of statewide streamflow characteristics based on data through water year 2009 for streamflow-gaging stations in or near Montana. Streamflow characteristics are presented for 408 streamflow-gaging stations in Montana and adjacent areas having 10 or more years of record. Data include the magnitude and probability of annual low and high streamflow, the magnitude and probability of low streamflow for three seasons (March–June, July–October, and November–February), streamflow duration statistics for monthly and annual periods, and mean streamflows for monthly and annual periods. Streamflow is considered to be regulated at streamflow-gaging stations where dams or other large-scale human modifications affect 20 percent or more of the contributing drainage basin. Separate streamflow characteristics are presented for the unregulated and regulated periods of record for streamflow-gaging stations with sufficient data.

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