SEARCH · Geology Reports

Results for “Computers and Geology”

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 1,189 records · Page 66Linked to original sources

USGS1978

Remote-sensing and subsurface definition of facies and structure related to uranium deposits, Powder River Basin, Wyoming

Computer-enhanced Landsat images of the southern Powder River Basin have been used to define facies and linear structural features within the Wasatch Formation. The facies distribution is detectable primarily because of a relation of vegetation density and type to the local substrate. The surface indications of facies are confirmed by sandstone/ mudstone ratios determined from logs of abundant exploration drill holes. These newly defined geologic features are spatially related to known uranium mineral occurrences and are believed to be related to mineralization in the following ways. (1) Major uranium occurrences are virtually restricted to an intermediate grain-size facies of the Wasatch, probably marking the axial zone of the depositional basin. (2) The axial zone is also marked by a change from one structural lineament domain to another, and the structures may have influenced details of fluvial-system patterns and sedimentation and (subsequently) the flow of uranium-bearing ground water. (3) A recently active linear structure may mark the current basin axis; it appears to have some relationship both to groundwater chemistry and the distribution of uranium occurrences, suggesting structural influence on relatively modern ground-water transport and uranium deposition. © 1978 Society of Economic Geologists, Inc.

Wyoming↗

USGS2022

U.S. Geological Survey national shoreline change— Summary statistics for updated vector shorelines (1800s–2010s) and associated shoreline change data for the Georgia and Florida coasts

Rates of shoreline change have been updated for the open-ocean sandy coastlines of Georgia and Florida as part of the U.S. Geological Survey’s Coastal Change Hazards programmatic focus. This work was formerly within the National Assessment of Shoreline Change project. Shorelines were compiled from the original report published in 2005, recent update reports, and additional light detection and ranging (lidar) shorelines which were extracted from lidar data collected prior to and following Hurricane Irma, which made landfall in September 2017. These shorelines were used to compute long- and short-term rates that incorporate the proxy-datum bias on a transect-by-transect basis. The proxy-datum bias accounts for the unidirectional onshore bias of proxy-based high water line shorelines relative to datum-based mean high water shorelines. In this study, the coast of Georgia exhibited the highest average rates of erosion and accretion in both the long term (approximately 150 years) and the short term (approximately 30 years). Shoreline positions from the mid-1800s through 2018 were used to update the shoreline change rates for Florida and Georgia using the Digital Shoreline Analysis System (DSAS) software.

Florida, Georgia↗

USGS1993

Policy and procedures for the management and archival storage of data collected for hydrologic investigations, U.S. Geological Survey, Indiana District

This report describes the policy and procedures used by the Indiana District of the U.S. Geological Survey, Water Resources Division, to manage and store data collected during hydrologic investigations. It is the policy of the Indiana District that data collected to meet the objectives of projects for hydrologic investigations be documented, organized, and archieved in a manner that (1) facilitates retrieval, evaluation, and use by other District personnel, and (2) enables verifi- cation of data contained in all reports and computer data bases.

Indiana↗

USGS2006

Nutrients in streams and rivers across the nation — 1992–2001

Nutrient compounds of nitrogen and phosphorus were investigated in streams and rivers sampled as part of the U.S. Geological Survey National Water-Quality Assessment (NAWQA) Program. Nutrient data were collected in 20 NAWQA study units during 1992-95, 16 study units during 1996-98, and 15 study units during 1999-2001. To facilitate comparisons among sampling sites with variable sampling frequency, daily loads were determined by using regression models that relate constituent transport to streamflow and time. Model results were used to compute mean annual loads, yields, and concentrations of ammonia, nitrate, total nitrogen, orthophosphate, and total phosphorus, which were compared among stream and river sampling sites. Variations in the occurrence and distribution of nutrients in streams and rivers on a broad national scale reflect differences in the sources of nutrient inputs to the upstream watersheds and in watershed characteristics that affect movement of those nutrients. Sites were classified by watershed size and by land use in the upstream watershed: agriculture, urban, and undeveloped (forest or rangeland). Selection of NAWQA urban sites was intended to avoid effects of major wastewater-treatment plants and other point sources, but in some locations this was not feasible. Nutrient concentrations and yields generally increased with anthropogenic development in the watershed. Median concentrations and yields for all constituents at sites downstream from undeveloped areas were less than at sites downstream from agricultural or urban areas. Concentrations of ammonia, orthophosphate, and total phosphorus at agricultural and urban sites were not significantly different; however, concentrations of nitrate and total nitrogen were higher at agricultural than at urban sites. Total nitrogen concentrations at agricultural sites were higher in areas of high nitrogen input or enhanced transport, such as irrigation or artificial drainage that can rapidly move water from cropland to streams (Midwest, Northern Plains, and western areas of the United States). Concentrations were lower in the Southeast, where more denitrification occurs during transport of nitrogen compounds in shallow ground water. At urban sites, high concentrations of ammonia and orthophosphate were more prevalent downstream from wastewater-treatment plants. At sites with large watersheds and high mean-annual streamflow (“large-watershed” sites), concentrations of most nutrients were significantly less than at sites downstream from agricultural or urban areas. Total nitrogen concentrations at large-watershed sites were higher in Midwest agricultural areas and lower in the Western United States, where agricultural and urban development is less extensive. Total phosphorus concentrations at large-watershed sites were higher in areas of greater potential erosion and low overall runoff such as the arid areas in the West. Although not as distinct as seasonal patterns of streamflow, geographic patterns of seasonally high and low concentrations of total nitrogen and total phosphorus were identified in the data. Seasonal patterns in concentrations of total nitrogen generally mirror seasonal patterns in streamflow in the humid Eastern United States but are inverse to seasonal patterns in streamflow in the semiarid interior West. Total phosphorus concentrations typically have the opposite regional relation with streamflow; high concentrations coincide with high streamflows in the interior West. In the NAWQA Program, sites downstream from relatively undeveloped areas were selected to provide a baseline for comparison to sites with potential effects of urban development and agriculture. Concentrations of nitrate, total nitrogen, and total phosphorus at NAWQA undeveloped sites were found to be greater than values reported by other studies for conditions of essentially no development (background conditions). Concentrations at NAWQA undeveloped sites represent conditions of relatively little development and provide insight in comparison to developed areas but should not, in general, be considered to represent background status. The U.S. Environmental Protection Agency has developed nutrient criteria to assist States in setting regional water-quality standards. Regional criteria were exceeded by total nitrogen concentrations at 72 percent of NAWQA undeveloped sites and by total phosphorus concentrations at 89 percent of these sites. Exceedances were even more extensive at sites with greater anthropogenic development upstream. The nitrogen criteria were exceeded at 96 percent of NAWQA sites classified as agricultural, urban, or mixed land use, and the phosphorus criteria were exceeded at 97 percent of these sites. Nationally, outflow loads of all nutrient constituents were strongly correlated to nonpoint-source inputs in the upstream watershed. The variation in input mass explained at least 69 percent of the variation in loads. Correlations between nonpoint-source input rates and outflow yields were not quite as good; variation in input rates explained only about 22-45 percent of the variations in nutrient yields. Estimation of nutrient outflow, on the basis of these correlations, likely could be improved if nationally consistent data were available for additional watershed characteristics.

Scientific Investigations Report↗

USGS2008

Converting NAD83 GPS Heights Into NAVD88 Elevations With LVGEOID, a Hybrid Geoid Height Model for the Long Valley Volcanic Region, California

A GPS survey of leveling benchmarks done in Long Valley Caldera in 1999 showed that the application of the National Geodetic Survey (NGS) geoid model GEOID99 to tie GPS heights to historical leveling measurements would significantly underestimate the caldera ground deformation (known from other geodetic measurements). The NGS geoid model was able to correctly reproduce the shape of the deformation, but required a local adjustment to give a realistic estimate of the magnitude of the uplift. In summer 2006, the U.S. Geological Survey conducted a new leveling survey along two major routes crossing the Long Valley region from north to south (Hwy 395) and from east to west (Hwy 203 - Benton Crossing). At the same time, 25 leveling bench marks were occupied with dual frequency GPS receivers to provide a measurement of the ellipsoid heights. Using the heights from these two surveys, we were able to compute a precise geoid height model (LVGEOID) for the Long Valley volcanic region. Our results show that although the LVGEOID and the latest NGS GEOID03 model practically coincide in areas outside the caldera, there is a difference of up to 0.2 m between the two models within the caldera. Accounting for this difference is critical when using the geoid height model to estimate the ground deformation due to magmatic or tectonic activity in the caldera.

Scientific Investigations Report↗

USGS2013

The use of process models to inform and improve statistical models of nitrate occurrence, Great Miami River Basin, southwestern Ohio

Statistical models of nitrate occurrence in the glacial aquifer system of the northern United States, developed by the U.S. Geological Survey, use observed relations between nitrate concentrations and sets of explanatory variables—representing well-construction, environmental, and source characteristics— to predict the probability that nitrate, as nitrogen, will exceed a threshold concentration. However, the models do not explicitly account for the processes that control the transport of nitrogen from surface sources to a pumped well and use area-weighted mean spatial variables computed from within a circular buffer around the well as a simplified source-area conceptualization. The use of models that explicitly represent physical-transport processes can inform and, potentially, improve these statistical models. Specifically, groundwater-flow models simulate advective transport—predominant in many surficial aquifers— and can contribute to the refinement of the statistical models by (1) providing for improved, physically based representations of a source area to a well, and (2) allowing for more detailed estimates of environmental variables. A source area to a well, known as a contributing recharge area, represents the area at the water table that contributes recharge to a pumped well; a well pumped at a volumetric rate equal to the amount of recharge through a circular buffer will result in a contributing recharge area that is the same size as the buffer but has a shape that is a function of the hydrologic setting. These volume-equivalent contributing recharge areas will approximate circular buffers in areas of relatively flat hydraulic gradients, such as near groundwater divides, but in areas with steep hydraulic gradients will be elongated in the upgradient direction and agree less with the corresponding circular buffers. The degree to which process-model-estimated contributing recharge areas, which simulate advective transport and therefore account for local hydrologic settings, would inform and improve the development of statistical models can be implicitly estimated by evaluating the differences between explanatory variables estimated from the contributing recharge areas and the circular buffers used to develop existing statistical models. The larger the difference in estimated variables, the more likely that statistical models would be changed, and presumably improved, if explanatory variables estimated from contributing recharge areas were used in model development. Comparing model predictions from the two sets of estimated variables would further quantify—albeit implicitly—how an improved, physically based estimate of explanatory variables would be reflected in model predictions. Differences between the two sets of estimated explanatory variables and resultant model predictions vary spatially; greater differences are associated with areas of steep hydraulic gradients. A direct comparison, however, would require the development of a separate set of statistical models using explanatory variables from contributing recharge areas. Area-weighted means of three environmental variables—silt content, alfisol content, and depth to water from the U.S. Department of Agriculture State Soil Geographic (STATSGO) data—and one nitrogen-source variable (fertilizer-application rate from county data mapped to Enhanced National Land Cover Data 1992 (NLCDe 92) agricultural land use) can vary substantially between circular buffers and volume-equivalent contributing recharge areas and among contributing recharge areas for different sets of well variables. The differences in estimated explanatory variables are a function of the same factors affecting the contributing recharge areas as well as the spatial resolution and local distribution of the underlying spatial data. As a result, differences in estimated variables between circular buffers and contributing recharge areas are complex and site specific as evidenced by differences in estimated variables for circular buffers and contributing recharge areas of existing public-supply and network wells in the Great Miami River Basin. Large differences in areaweighted mean environmental variables are observed at the basin scale, determined by using the network of uniformly spaced hypothetical wells; the differences have a spatial pattern that generally is similar to spatial patterns in the underlying STATSGO data. Generally, the largest differences were observed for area-weighted nitrogen-application rate from county and national land-use data; the basin-scale differences ranged from -1,600 (indicating a larger value from within the volume-equivalent contributing recharge area) to 1,900 kilograms per year (kg/yr); the range in the underlying spatial data was from 0 to 2,200 kg/yr. Silt content, alfisol content, and nitrogen-application rate are defined by the underlying spatial data and are external to the groundwater system; however, depth to water is an environmental variable that can be estimated in more detail and, presumably, in a more physically based manner using a groundwater-flow model than using the spatial data. Model-calculated depths to water within circular buffers in the Great Miami River Basin differed substantially from values derived from the spatial data and had a much larger range. Differences in estimates of area-weighted spatial variables result in corresponding differences in predictions of nitrate occurrence in the aquifer. In addition to the factors affecting contributing recharge areas and estimated explanatory variables, differences in predictions also are a function of the specific set of explanatory variables used and the fitted slope coefficients in a given model. For models that predicted the probability of exceeding 1 and 4 milligrams per liter as nitrogen (mg/L as N), predicted probabilities using variables estimated from circular buffers and contributing recharge areas generally were correlated but differed significantly at the local and basin scale. The scale and distribution of prediction differences can be explained by the underlying differences in the estimated variables and the relative weight of the variables in the statistical models. Differences in predictions of exceeding 1 mg/L as N, which only includes environmental variables, generally correlated with the underlying differences in STATSGO data, whereas differences in exceeding 4 mg/L as N were more spatially extensive because that model included environmental and nitrogen-source variables. Using depths to water from within circular buffers derived from the spatial data and depths to water within the circular buffers calculated from the groundwater-flow model, restricted to the same range, resulted in large differences in predicted probabilities. The differences in estimated explanatory variables between contributing recharge areas and circular buffers indicate incorporation of physically based contributing recharge area likely would result in a different set of explanatory variables and an improved set of statistical models. The use of a groundwater-flow model to improve representations of source areas or to provide more-detailed estimates of specific explanatory variables includes a number of limitations and technical considerations. An assumption in these analyses is that (1) there is a state of mass balance between recharge and pumping, and (2) transport to a pumped well is under a steady state flow field. Comparison of volumeequivalent contributing recharge areas under steady-state and transient transport conditions at a location in the southeastern part of the basin shows the steady-state contributing recharge area is a reasonable approximation of the transient contributing recharge area after between 10 and 20 years of pumping. The first assumption is a more important consideration for this analysis. A gradient effect refers to a condition where simulated pumping from a well is less than recharge through the corresponding contributing recharge area. This generally takes place in areas with steep hydraulic gradients, such as near discharge locations, and can be mitigated using a finer model discretization. A boundary effect refers to a condition where recharge through the contributing recharge area is less than pumping. This indicates other sources of water to the simulated well and could reflect a real hydrologic process. In the Great Miami River Basin, large gradient and boundary effects—defined as the balance between pumping and recharge being less than half—occurred in 5 and 14 percent of the basin, respectively. The agreement between circular buffers and volume-equivalent contributing recharge areas, differences in estimated variables, and the effect on statisticalmodel predictions between the population of wells with a balance between pumping and recharge within 10 percent and the population of all wells were similar. This indicated process-model limitations did not affect the overall findings in the Great Miami River Basin; however, this would be model specific, and prudent use of a process model needs to entail a limitations analysis and, if necessary, alterations to the model.

Ohio↗

USGS1979

Nonpoint-source discharges in Pequea Creek Basin, Pennsylvania, 1977

A study of Pequea Creek included measurement of streamflow and collection of water and bottom-material samples during selected base-flow and storm periods from February to December 1977. Samples were analyzed for nitrogen and phosphorus species, suspended sediment, organic carbon, and pesticides. Daily mean constituent concentrations and discharges transported from the basin were computed for a gaging station near the mouth. Intermittent constituent mean concentrations and discharges were computed for storms at the six subbasin sites. The objective of this project was to assess the magnitudes and types of nonpoint discharges that affect the water quality of Pequea Creek. The project included the determination of (1) the total discharges of suspended sediment, nitrogen, and phosphorus from the basin; (2) intermittent storm and base-flow discharges from six subbasin sites of varying size, geology, and land use; (3) the difference in magnitudes of the discharges during base-flow periods and storms; and (4) which variables most affect the transport of these constituents. The yields measured from the Pequea Creek basin for the period February to December 1977 were among the highest measured in the lower Susquehanna River basin. Some preliminary relations between constituents were examined using linear regression techniques on all of the data for each site. Direct runoff transported the majority of the suspended sediment, total phosphorus, and suspended organic carbon from the basin; the other constituents were transported mainly during base flow. (USGS).

Pennsylvania↗

USGS1983

U. S. GEOLOGICAL SURVEY LAND REMOTE SENSING ACTIVITIES.

USGS uses all types of remotely sensed data, in combination with other sources of data, to support geologic analyses, hydrologic assessments, land cover mapping, image mapping, and applications research. Survey scientists use all types of remotely sensed data with ground verifications and digital topographic and cartographic data. A considerable amount of research is being done by Survey scientists on developing automated geographic information systems that can handle a wide variety of digital data. The Survey is also investigating the use of microprocessor computer systems for accessing, displaying, and analyzing digital data.

Conference Paper↗

USGS2021

Linear regression model documentation and updates for computing water-quality constituent concentrations or densities using continuous real-time water-quality data for the Kansas River, Kansas, July 2012 through September 2019

The Kansas River provides drinking water to about 800,000 people in northeastern Kansas. Water-treatment facilities that use the Kansas River as a water-supply source use chemical and physical processes during water treatment to remove contaminants before public distribution. Advanced notification of changing water-quality conditions near water-supply intakes allows water-treatment facilities to proactively adjust treatment. The U.S. Geological Survey (USGS), in cooperation with the Kansas Water Office (funded in part through the Kansas Water Plan), the Kansas Department of Health and Environment, The Nature Conservancy, the City of Lawrence, the City of Manhattan, the City of Olathe, the City of Topeka, and Johnson County WaterOne, collected water-quality data at the Kansas River at Wamego (USGS site 06887500; hereafter referred to as the “Wamego site”) and De Soto (USGS site 06892350; hereafter referred to as the “De Soto site”) monitoring sites to update previously published regression models relating continuous water-quality sensor measurements, streamflow, and seasonal components to discretely sampled water-quality constituent concentrations or densities. Linear regression analysis was used to update and develop models for total dissolved solids, major ions, hardness as calcium carbonate, nutrients (nitrogen and phosphorus species), chlorophyll a , total suspended solids, suspended sediment, and fecal indicator bacteria at the Wamego and De Soto monitoring sites using data collected during July 2012 through September 2019. The water-quality information documented in this report can be used as guidance for water-treatment processes and to characterize changes in water-quality conditions in the Kansas River over time that would not be otherwise possible.

Kansas↗

USGS2014

High-precision relocation of long-period events beneath the summit region of Kı̄lauea Volcano, Hawai‘i, from 1986 to 2009

Long-period (0.5–5 Hz, LP) seismicity has been recorded for decades in the summit region of Kı̄lauea Volcano, Hawai‘i, and is postulated as linked with the magma transport and shallow hydrothermal systems. To better characterize its spatiotemporal occurrence, we perform a systematic analysis of 49,030 seismic events occurring in the Kı̄lauea summit region from January 1986 to March 2009 recorded by the &sim;50-station Hawaiian Volcano Observatory permanent network. We estimate 215,437 P wave spectra, considering all events on all stations, and use a station-averaged spectral metric to consistently classify LP and non-LP seismicity. We compute high-precision relative relocations for 5327 LP events (43% of all classified LP events) using waveform cross correlation and cluster analysis with 6.4 million event pairs, combined with the source-specific station term method. The majority of intermediate-depth (5–15 km) LPs collapse to a compact volume, with remarkable source location stability over 23 years indicating a source process controlled by geological or conduit structure.

Hawaii↗

USGS2005

Numerical assessment of a landfill compliance limit

The PLASM and Random Walk ground-water flow and contaminant transport models were used to assess the potential impact of various proposed regulatory compliance distances on landfill siting. Contaminant transport modeling was performed for 16 generalized geological sequences representative of hydrogeological conditions over an estimated 90 to 95 percent of Illinois. Results of this modeling indicate that about 50 percent of the state would be hydrogeologically suitable for landfilling of nonhazardous wastes if the compliance distance was 100 feet. With a compliance distance of 500 feet, about 55 percent of the state would be hydrogeologically suitable. This work demonstrates the utility of computer modeling in the development of regulations governing landfill siting.

Groundwater↗

USGS1992

Cartographic applications software

The Office of the Assistant Division Chief for Research, National Mapping Division, develops computer software for the solution of geometronic problems in the fields of surveying, geodesy, remote sensing, and photogrammetry. Software that has been developed using public funds is available on request for a nominal charge to recover the cost of duplication.

Fact Sheet↗

USGS1992

Selected papers in the applied computer sciences 1992

This compilation of short papers reports on technical advances in the applied computer sciences. The papers describe computer applications in support of earth science investigations and research. This is the third volume in the series "Selected Papers in the Applied Computer Sciences." Listed below are the topics addressed in the compilation: Integration of geographic information systems and expert systems for resource management, Visualization of topography using digital image processing, Development of a ground-water data base for the southeastern Uited States using a geographic information system, Integration and aggregation of stream-drainage data using a geographic information system, Procedures used in production of digital geologic coverage using compact disc read-only memory (CD-ROM) technology, and Automated methods for producing a technical publication on estimated water use in the United States.

Bulletin↗

USGS2002

Assessment of undiscovered deposits of gold, silver, copper, lead, and zinc in the United States: A Portable Document (PDF) recompilation of USGS Open-File Report 96-96 and Circular 1178

This publication contains the results of a national mineral resource assessment study. The study (1) identifies regional tracts of ground believed to contain most of the nation's undiscovered resources of gold, silver, copper, lead, and zinc in conventional types of deposits; and (2) includes probabilistic estimates of the amounts of these undiscovered resources in most of the tracts. It also contains a table of the significant known deposits in the tracts, and includes descriptions of the mineral deposit models used for the assessment. The assessment was previously released in two major publications. The conterminous United States assessment was published in 1996 as USGS Open-File Report 96-96. Subsequently, the Alaska assessment was combined with the conterminous assessment in 1998 and released as USGS Circular 1178. This new recompilation was undertaken for several reasons. First, the graphical browser software used in Circular 1178 was ONLY compatible with the Microsoft Windows operating system. It was incompatible with the Macintosh operating system, Linux, and other types of Unix computers. Second, the browser on Circular 1178 is much less intuitive to operate, requiring most users to follow a tutorial to understand how to navigate the information on the CD. Third, this release corrects several errors and numbering inconsistencies in Circular 1178.

Open-File Report↗

USGS2018

Revised technical implementation plan for the ShakeAlert system—An earthquake early warning system for the West Coast of the United States

The U.S. Geological Survey (USGS), along with partner organizations, has developed an earthquake early warning (EEW) system called ShakeAlert for the highest risk areas of the United States: namely, California, Oregon, and Washington. The purpose of the system is to reduce the impact of earthquakes and save lives and property by providing alerts to institutional users and the public. Using networks of ground-motion sensors and sophisticated computer algorithms, ShakeAlert can detect an earthquake seconds after it begins, calculate its location and magnitude, and estimate the resulting intensity of shaking. Alerts can then be sent to people and systems that may experience damaging shaking, allowing them to take appropriate protective actions. Depending on the user’s distance from the earthquake, alerts may be delivered before, during, or after the arrival of strong shaking. ShakeAlert is built on the foundation of the sensor networks and data processing infrastructure of the USGS-led Advanced National Seismic System. However, these networks were not originally designed for EEW; old equipment needs to be updated and new stations must be added to construct EEW-capable networks. The ShakeAlert data-processing infrastructure includes redundant servers that are geographically distributed at monitoring centers in Seattle, Washington, as well as Menlo Park, Berkeley, and Pasadena in California. Three data-processing layers collect raw ground-motion data from field stations (data layer), analyze these data to estimate the area and intensity of the resulting shaking (production layer), and publish alert products as appropriate for end users (alert layer). The alert layer can support thousands of institutional users and alert redistributors, but the USGS does not have the mission, infrastructure, or expertise to perform public notifications and is therefore recruiting technology enablers from the private sector. Additionally, ShakeAlert will coordinate with both public and private partners to accomplish consistent and ongoing public communication, education, and outreach. The estimated cost of completing the ShakeAlert infrastructure and sensor networks is \$39.4 million and has an estimated annual operation and maintenance cost of \$28.6 million per year. Building a highly reliable data telemetry infrastructure would cost another \$20.5 million and operating this telemetry system would add \$49.8 million per year; however, these costs could be reduced if project partners provide bandwidth on existing systems.

Open-File Report↗

USGS2022

Documentation of models describing relations between continuous real-time and discrete water-quality constituents in the Little Arkansas River, south-central Kansas, 1998–2019

Data were collected at two monitoring sites along the Little Arkansas River in south-central Kansas that bracket most of the easternmost part of the Equus Beds aquifer. The data were used as part of the city of Wichita’s aquifer storage and recovery project to evaluate source water quality. The U.S. Geological Survey, in cooperation with the City of Wichita, has continued to monitor the water quality of these sites through 2019 to update previously published regression-based models using continuously measured physicochemical properties and discretely sampled water-quality constituents of interest. The purpose of this report is to provide an update of the previously published linear regression models that have been used to continuously compute estimates of water-quality constituent concentrations or densities at these two sites. Water-quality constituent model updates include those for dissolved and suspended solids, suspended-sediment concentration, hardness, alkalinity, primary ions (bicarbonate, calcium, sodium, chloride, and sulfate), nutrients (total Kjeldahl nitrogen and total phosphorus), total organic carbon, indicator bacteria ( Escherichia coli and fecal coliform bacteria), a trace element (arsenic), and a pesticide (atrazine). Regression analyses were used to develop surrogate models that related continuously measured physicochemical properties, streamflow, and seasonal components to discretely sampled water-quality constituent concentrations or densities. Specific conductance was an explanatory variable for dissolved solids, primary ions, and atrazine. Turbidity was an explanatory variable for total suspended solids and sediment, nutrients, total organic carbon, and indicator bacteria. Streamflow and water temperature were explanatory variables for dissolved arsenic. Seasonal components were included as explanatory variables for atrazine models. The amount of variance explained by most of the updated models was within 5 percent of previously published models.

Kansas↗

USGS2024

Mapping Arundo donax (Arundo cane) with multispectral imagery before, during, and after herbicide treatment along the Rio Grande in Webb County, Texas, 2020–21

Arundo donax , commonly called Arundo cane, giant reed, or Carrizo cane, is an invasive bamboo-like perennial grass common in riparian areas throughout the southwestern United States. In Texas, not only does it negatively affect riparian ecosystems, but it has also become a problem for border security because it reduces visibility along the Rio Grande. To address these problems, in 2015 the Texas State Soil and Water Conservation Board was authorized by the Texas State Legislature to develop a program to eradicate Arundo cane along the Rio Grande. In 2020, the Texas State Soil and Water Conservation Board applied imazapyr and glyphosate herbicides along a 19.3-kilometer reach of the Rio Grande, northwest of Laredo, Texas. The U.S. Geological Survey, in cooperation with the Texas State Soil and Water Conservation Board and the Webb Soil and Water Conservation District, used WorldView-3 Standard high-resolution satellite imagery to map Arundo cane extent along the reach before , during , and after the herbicide-treatment period on June 30, 2020, September 26, 2020, and May 7, 2021, respectively. A maximum likelihood supervised classification analysis was computed on the images to map the spatial extent and estimate the area covered by Arundo cane. The estimated area covered by Arundo cane in the before classification was 1,282,000 square meters, in the during classification was 1,064,000 square meters, and in the after classification was 1,108,000 square meters. The qualitative comparison of the three images shows that there was an overall decrease in vegetation classified as Arundo cane throughout the study area.

Texas↗

USGS2004

Generalized estimates from streamflow data of annual and seasonal ground-water-recharge rates for drainage basins in New Hampshire

This report presents regression equations to estimate generalized annual and seasonal ground-water-recharge rates in drainage basins in New Hampshire. The ultimate source of water for a ground-water withdrawal is aquifer recharge from a combination of precipitation on the aquifer, ground-water flow from upland basin areas, and infiltration from streambeds to the aquifer. An assessment of ground-water availability in a basin requires that recharge rates be estimated under `normal' conditions and under assumed drought conditions. Recharge equations were developed by analyzing streamflow, basin characteristics, and precipitation at 55 unregulated continuous record stream-gaging stations in New Hampshire and in adjacent states. In the initial step, streamflow records were analyzed to estimate a series of annual and seasonal ground-water-recharge components of streamflow in each drainage basin evaluated in this study. Regression equations were then developed relating the series of annual and seasonal ground-water-recharge values to the corresponding series of annual and seasonal precipitation values as determined at the centroid of each drainage basin. This resulted in one equation for each of the 55 basins for each of the four seasonal periods and the annual period, or a total of 275 regression equations. Average annual and seasonal precipitation data for 1961-90 were then used to compute a set of normalized ground-water-recharge values that reflected the long-term average annual and seasonal variations (normalized) and mean recharge characteristics of each drainage basin. Ordinary-least-squares regression was applied in the process of selecting 10 out of 93 possible basin and climatic characteristics for further testing in the development of the equations for computing the generalized estimate of annual and seasonal ground-water recharge based on the set of normalized recharge values. Generalized-least-squares regression was used for the final parameter estimation and error evaluation. The following basin and climatic characteristics were found to be statistically significant predictors for at least one of the dependent variables: average annual, summer, and spring precipitation as determined at U.S. Geological Survey stream-gaging stations; average annual basin-centroid precipitation; average mean annual basin temperature; average minimum winter basin temperature; percent coniferous forest in a basin; percent mixed coniferous and deciduous forest in a basin; average fall basin-centroid precipitation; and average annual snowcover. These 10 basin and climatic characteristics were selected because they were statistically significant based on several statistical parameters that evaluated which combination of characteristics contributed the most to the predictive accuracy of the regression-equation models. A geographic information system is required to measure the values of the predictor variables for the equations developed in the study. The average annual normalized ground-water recharge was 21.0 in. This value was determined by generalized-least-squares (GLS) regression analysis for all of the basins used in the normalized ground-water recharge analysis for precipitation from 1961-90. The average winter (January 1-March 15) ground-water recharge was 4.3 in., average spring (March 16-May 31) ground-water recharge was 9.0 in., average summer (June 1-October 31) ground-water recharge was 4.0 in., and average fall (November 1-December 31) ground-water recharge was 3.6 in. Normalized ground-water recharge ranged annually from 12.3 to 31.8 in., for winter from 2.30 to 7.82 in., for spring from 5.16 to 13.7 in., for summer from 1.45 to 10.2 in., and for fall from 2.21 to 6.06 in.

New Hampshire↗