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

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At least 667 records · Page 37Linked to original sources
USGS2017

Groundwater flow model for the Little Plover River basin in Wisconsin’s Central Sands

The Little Plover River is a groundwater-fed stream in the sand plains region of central Wisconsin. In this region, sandy sediment deposited during or soon after the last glaciation forms an important unconfined sand and gravel aquifer. This aquifer supplies water for numerous high-capacity irrigation, municipal, and industrial wells that support a thriving agricultural industry. In recent years the addition of many new wells, combined with observed diminished flows in the Little Plover and other nearby rivers, has raised concerns about the impacts of the wells on groundwater levels and on water levels and flows in nearby lakes, streams, and wetlands. Diverse stakeholder groups, including well operators, Growers, environmentalists, local land owners, and regulatory and government officials have sought a better understanding of the local groundwater-surface water system and have a shared desire to balance the water needs of the he liagricultural, industrial, and urban users with the maintenance and protection of groundwater-dependent natural resources. To help address these issues, the Wisconsin Department of Natural Resources requested that the Wisconsin Geological and Natural History Survey and U.S. Geological Survey cooperatively develop a groundwater flow model that could be used to demonstrate the relationships among groundwater, surface water, and well withdrawals and also be a tool for testing and evaluating alternative water management strategies for the central sands region. Because of an abundance of previous studies, data availability, local interest, and existing regulatory constraints the model focuses on the Little Plover River watershed, but the modeling methodology developed during this study can apply to much of the larger central sands of Wisconsin. The Little Plover River groundwater flow model simulates three-dimensional groundwater movement in and around the Little Plover River basin under steady-state and transient conditions. This model explicitly includes all high-capacity wells in the model domain and simulates seasonal variations in recharge and well pumping. The model represents the Little Plover River, and other significant streams and drainage ditches in the model domain, as fully connected to the groundwater system, computes stream base flow resulting from groundwater discharge, and routes the flow along the stream channel. A separate soil-water-balance (SWB) model was used to develop groundwater recharge arrays as input for the groundwater flow model. The SWB model uses topography, soils, land use, and climatic data to estimate recharge as deep drainage from the soil zone. The SWB model explicitly includes recharge originating as irrigation water, and computes irrigation using techniques similar to those used by local irrigation operators. The groundwater flow model uses the U.S. Geological Survey’s MODFLOW modeling code which is freely available, widely accepted, and commonly used by the groundwater community. The groundwater flow model and the SWB model use identical high-resolution numerical grids having model cells 100 feet on a side, with physical properties assigned to each grid cell. This grid allows accurate geographic placement of wells, streams, and other model features. The 3-dimensional grid has three layers; layers 1 and 2 represent the sand and gravel aquifer and layer 3 represents the underlying sandstone. The distribution of material properties in the model (hydraulic conductivity, aquifer thickness, etc.) comes from previous published geologic studies of the region, updated by calibration to recent streamflow and groundwater level data. The SWB model operates on a daily time step. The groundwater flow model was calibrated to monthly stress periods with time steps ranging from 1 to 16 days. More detailed time discretization is possible. The groundwater model was calibrated to water-level and streamflow data collected during 2013 and 2014 by adjusting model parameters (primarily hydraulic conductivity, storage, and recharge) until the model produced a conditionally optimal fit between field observations and model output, subject to consistency with previously published geologic studies. Calibration was performed under both steady and transient conditions, and used a sophisticated parameter-estimation procedure (PEST) for the calibration process and to identify important model parameters. For the Little Plover River, the two most important parameters are the global recharge multiplier and the hydraulic conductivity of the stream bed. The calibrated model produces water-level and mass-balance results that are consistent with field observations and previous studies of the area. The completed model is a powerful tool for testing and demonstrating alternative water-management scenarios. Example model applications described in this report include simulating how the cumulative impacts of pumping and land-use change have affected average baseflow in the Little Plover River. Depletion-potential mapping represents a method for predicting which wells and well locations have the greatest impact on nearby surface-water resources. The completed model is publicly available, along with a companion user’s guide to assist with its operation, at http://wgnhs.org/littleplover- river-groundwater-model.

Wisconsin↗
USGS1988

Recording strong motion studies

Instruments now permit strong‐motion signals to be recorded over broader band widths, with wider dynamic range and signal resolution and with better data accessibility via computer. These advantages are utilized by the General Earthquake Observation System (GEOS) developed by the United States Geological Survey, by which a microcomputer‐controlled system provides improved strong‐motion data sets, as described here by a member of the development team. The paper was originally given at a joint meeting of the US/Japan Panel on Wind and Seismic Effects.

Batiment International, Building Research and Prac↗
USGS2023

Water balance characterization of the early 21st century drought in the western United States

Monthly temperature and precipitation data for 923 United States Geological Survey 8-digit hydrologic units are used as inputs to a monthly water balance model to compute monthly actual evapotranspiration, soil moisture storage, and runoff across the western United States (U.S.) for the period 1900 through 2020. Time series of these water balance variables are examined to characterize and explain the dry conditions across the western U.S. since the year 2000. Results indicate that although precipitation deficits account for most of the changes in actual evapotranspiration and runoff, increases in temperature primarily explain decreases in soil moisture storage. Specifically, temperature has been particularly impactful on the magnitude of negative departures of soil moisture storage during the spring (April through June) and summer (July through September) seasons. These effects on soil moisture may be particularly detrimental to agriculture in regions already stressed by drought such as the western U.S.

Journal of the American Water Resources Associatio↗
USGS2014

Metrics for comparing dynamic earthquake rupture simulations

Earthquakes are complex events that involve a myriad of interactions among multiple geologic features and processes. One of the tools that is available to assist with their study is computer simulation, particularly dynamic rupture simulation. A dynamic rupture simulation is a numerical model of the physical processes that occur during an earthquake. Starting with the fault geometry, friction constitutive law, initial stress conditions, and assumptions about the condition and response of the near‐fault rocks, a dynamic earthquake rupture simulation calculates the evolution of fault slip and stress over time as part of the elastodynamic numerical solution (Ⓔ see the simulation description in the electronic supplement to this article). The complexity of the computations in a dynamic rupture simulation make it challenging to verify that the computer code is operating as intended, because there are no exact analytic solutions against which these codes’ results can be directly compared. One approach for checking if dynamic rupture computer codes are working satisfactorily is to compare each code’s results with the results of other dynamic rupture codes running the same earthquake simulation benchmark. To perform such a comparison consistently, it is necessary to have quantitative metrics. In this paper, we present a new method for quantitatively comparing the results of dynamic earthquake rupture computer simulation codes.

Seismological Research Letters↗
USGS2011

A data-input program (MFI2005) for the U.S. Geological Survey modular groundwater model (MODFLOW-2005) and parameter estimation program (UCODE_2005)

The MFI2005 data-input (entry) program was developed for use with the U.S. Geological Survey modular three-dimensional finite-difference groundwater model, MODFLOW-2005. MFI2005 runs on personal computers and is designed to be easy to use; data are entered interactively through a series of display screens. MFI2005 supports parameter estimation using the UCODE_2005 program for parameter estimation. Data for MODPATH, a particle-tracking program for use with MODFLOW-2005, also can be entered using MFI2005. MFI2005 can be used in conjunction with other data-input programs so that the different parts of a model dataset can be entered by using the most suitable program.

Open-File Report↗
USGS1994

Documentation of a computer program to simulate transient leakage from confining units using the modular finite-difference, ground-water flow model

Transient leakage into or out of a compressible fine-grained confining unit results from ground- water storage changes within the unit. The computer program described in this report provides a new method of simulating transient leakage using the U.S. Geological Survey modular finite- difference ground-water flow model (MODFLOW). The new program is referred to as the Transient- Leakage Package. The Transient-Leakage Package solves integrodifferential equations that describe flow across the upper and lower boundaries of confining units. For each confining unit, vertical hydraulic conductivity, thickness, and specific storage are specified in input arrays. These properties can vary from cell to cell and the confining unit need not be present at all locations in the grid; however, the confining units must be bounded above and below by model layers in which head is calculated or specified. The package was used in an example problem to simulate drawdown around a pumping well in a system with two aquifers separated by a confining unit. For drawdown values in excess of 1 centimeter, the solution using the new package closely matched an exact analytical solution. The problem also was simulated without the new package by using a separate model layer to represent the confining unit. That simulation was refined by using two model layers to represent the confining unit. The simulation using the Transient-Leakage Package was faster and more accurate than either of the simulations using model layers to represent the confining unit.

Open-File Report↗
USGS1996

Assessment of scour-critical data collected at selected bridges and culverts in South Carolina, 1990-92

Data at bridges and culverts were collected at 3,506 stream crossings in South Carolina during 1990-92. The data include general information unique to the structure; structural data; and hydraulic, geomorphic, and vegetation information. The data are stored in the U.S. Geological Survey South Carolina District Bridge-Scour Data Base. Observed- and potential-scour indexes were computed from the applicable data variables. Sites with observed-scour indexes exceeding ten and (or) potential-scour indexes exceeding 20 are considered to have significant scour-related problems. Of the 3,506 sites inspected, 257 sites had an observed-scour index exceeding ten, 214 sites had a potential-scour index exceeding 20, and 85 sites had observed- and potential-scour indexes exceeding both threshold values.

South Carolina↗
USGS1997

Digital data sets that describe aquifer characteristics of the Rush Springs Aquifer in western Oklahoma

This diskette contains digitized aquifer boundaries and maps of hydraulic conductivity, recharge, and ground-water level elevation contours for the Rush Spring aquifer in western Oklahoma. This area encompasses all or part of Blaine, Caddo, Canadian, Comanche, Custer, Dewey, Grady, Stephens, and Washita Counties. These digital data sets were developed by Mark F. Becker to use as input into a computer model that simulated ground-water flow in the Rush Springs aquifer (Mark F. Becker, U.S. Geological Survey, written commun., 1997). For the purposes of modeling the ground-water flow in the Rush Springs aquifer, Mark F. Becker (written commun., 1997) defined the Rush Springs aquifer to include the Rush Springs Formation, alluvial and terrace deposits along major streams, and parts of the Marlow Formations, particularly in the eastern part of the aquifer boundary area. The Permian-age Rush Springs Formation consists of highly cross-bedded sandstone with some interbedded dolomite and gypsum. The Rush Springs Formation is overlain by Quaternary-age alluvial and terrace deposits that consist of unconsolidated clay, silt, sand, and gravel. The Rush Springs Formation is underlain by the Permian-age Marlow Formation that consists of interbedded sandstones, siltstones, mudstones, gypsum-anhydrite, and dolomite beds (Mark F. Becker, written commun., 1997). The parts of the Marlow Formation that have high permeability and porosity are where the Marlow Formation is included as part of the Rush Springs aquifer. The Rush Springs aquifer underlies about 2,400 square miles of western Oklahoma and is an important source of water for irrigation, livestock, industrial, municipal, and domestic use. Irrigation wells are reported to have well yields greater than 1,000 gallons per minute (Mark F. Becker, written commun., 1997). Mark F. Becker created some of the aquifer boundaries, hydraulic conductivity, and recharge data sets by digitizing parts of previously published surficial geology maps. The hydraulic conductivity and recharge values are the input data to the ground-water flow model (Mark F. Becker, written commun., 1997). The water-level elevation data set was prepared at a scale of 1:250,000 by Mark F. Becker (written commun., 1997) from water levels measured in wells prior to the year 1950. Ground-water flow models are numerical representations that simplify and aggregate natural systems. Models are not unique; different combinations of aquifer characteristics may produce similar results. Therefore, values of hydraulic conductivity and recharge used in the model and presented in this data set are not precise, but are within a reasonable range when compared to independently collected data.

Oklahoma↗
USGS1997

Hydrologic budgets of regional aquifer systems of the United States for predevelopment and development conditions

Ground-water budgets are presented in this report for 14 regionally extensive aquifer systems; pumpage from 11 of these systems provided from 40 to 50 percent of the ground water withdrawn in the United States during the 1970's and 1980's. The budgets are based on simulation results from computer-based models developed as part of the Regional Aquifer-System Analysis Program of the U.S. Geological Survey. Most of the models cover large areas (30,000-300,000 square miles) and generally are constructed with coarse-mesh finite-difference grids designed to simulate regional ground-water flow. The groundwater budgets derived from these models generally do not include local flow that enters and exits regional aquifers after traveling only a few miles or flow in overlying surficial aquifers. Budgets are presented for predevelopment and recent pumping conditions for most of the aquifer systems.

Professional Paper↗
USGS2021

Groundwater/surface-water interactions in the Partridge River Basin and evaluation of hypothetical future mine pits, Minnesota

The Partridge River Basin (PRB) covers 156 square miles in northeastern Minnesota with headwaters in the Mesabi Iron Range. The basin is characterized by extensive wetlands, lakes, and streams in poorly drained and often thin glacial material overlying Proterozoic bedrock. To better understand the interaction between these extensive surface water features and the groundwater system, a three-dimensional, steady-state, groundwater-flow model of the PRB was developed by the U.S. Geological Survey in cooperation with the Great Lakes Indian Fish & Wildlife Commission using the finite-difference computer code MODFLOW-NWT. The model simulates steady-state base flow in streams and groundwater interactions using the streamflow routing (SFR2) package. Existing mining features including tailings basins, stockpiles, pumped mine pits, and flooded mine pits were simulated using either high hydraulic conductivity zones or the drain (DRN) package. The unsaturated zone flow (UZF) package was used to better represent the groundwater system in areas with a high water table and for wetlands often associated with such areas. UZF typically is used to represent unsaturated zone processes but also can simulate the rejection of recharge and groundwater discharge to the land surface when the water table is near land surface. The steady-state model used data from the 2011 to 2013 period when 2011 high-resolution land surface (light detecting and ranging [lidar]) data were available that reflected land-surface and water elevations from mining activity in the basin. The parameter-estimation software suite PEST_HP was used to obtain a best fit of the modeled to measured groundwater levels, streamflow, pit inflow rates, and mapped peat deposits. The PEST calibration used the target residuals from two models with the same model parameters and targets from two separate periods: (1) a 1995–2015 calibration model, which provided a larger number of calibration targets, and (2) a 2011–2013 mining conditions model, which included calibration targets that reflected conditions consistent with the modeled mine-workings topography. Calibration of the PRB model resulted in ranges of glacial horizontal hydraulic conductivity parameters that generally agreed with literature values and other models of the region. Horizontal hydraulic conductivity of the bedrock was higher in the upper bedrock layers where numerous and continuous fractures have been observed and lower in the deeper bedrock layers. Average basin-wide calibrated infiltration was 5.3 inches per year. An average of 4.6 inches per year of infiltration crosses the water table and becomes recharge and 0.7 inch per year is rejected by UZF due to saturated conditions at the land surface. Simulated groundwater runoff (the sum of rejected recharge and groundwater seepage to the land surface) can either be routed to streams or removed from the model as evapotranspiration. The calibrated model indicates relatively shallow groundwater-flow paths dominating and approximately 50 percent of the stream base flow coming from groundwater runoff. The 2011–2013 mining conditions model was then used to develop five model scenarios simulating the response of the groundwater and surface-water system to potential hydrologic stress. The purpose of these mine pit scenarios is to present a possible workflow to quantify a model’s uncertainty for a given model forecast and serve as a possible guide for initial data collection that may improve a future model’s ability to make such a forecast. The scenarios included one scenario with the currently existing Peter Mitchell pit at final buildout and flooded to an elevation of 1,500 feet, and four scenarios with a hypothetical, new mine pit plus the flooded Peter Mitchell at final buildout. The five model scenarios were used to forecast streamflow at six locations in the PRB, pit inflow rates for the new mine pits and the flooded Peter Mitchell pit, and the average depth to water in 12 wetlands. A linear uncertainty analysis was performed using information from the PEST calibration and tools in the PyEMU python package to assess model uncertainty propagation to the model forecasts. Streamflows generally were reduced with future mining and the greatest streamflow reductions occurred from the flooded Peter Mitchell Pit, probably due to its large size. Average depth to groundwater in wetlands was most affected the closer the wetland was to a new mine pit. Linear uncertainty methods were also used to evaluate data worth, which is the ability for potential new groundwater elevation observations to reduce the uncertainty in scenario forecasts. Data worth was performed for a grid of new hydraulic head observations. Overall, areas with nonnegligible data worth generally corresponded to wetland areas with no groundwater seepage to land surface from UZF. These model behaviors indicated that the land-surface boundary condition simulated by the UZF package was pinning the groundwater elevations to the land surface in areas with groundwater seepage (33 percent of the 2011–2013 base conditions model) such that the sensitivity to new observations in these areas was minimal. Therefore, representing wetlands as boundary conditions minimized the usefulness of data worth calculations because wetland areas were present over a large part of the model domain. Probabilistic capture zones were estimated for each of the mines in the model scenarios. A capture zone represents the area contributing recharge to a model feature, like a well or a mine pit, and can be calculated by forward tracking particles from the water table. By using Monte Carlo techniques, it is possible to generate estimated capture zones that include the probability of recharge capture given the uncertainty present in the model. Monte Carlo techniques use randomly generated model parameter sets sampled from a plausible parameter range to create many possible realizations. The resulting capture zone arrays were calculated by tallying the total number of realizations in which a particle from a model cell was captured by the feature. Probabilities from the Monte Carlo runs ranged from 1 (captured in 100 percent of the runs) near the pits to 0 (captured in 0 percent of the runs) at the edges of the capture zone. Capture zones were not always spatially continuous; for example, the capture zone for the proposed mine pits south of the flooded Peter Mitchell pit was discontinuous with capture surrounding the proposed mine pit and north of the flooded Peter Mitchell pit. This northern section represents deeper groundwater flow paths that originate in the topographic high, move under the flooded pit, and discharge into the proposed pit. This pattern of capture indicates the possibility of some deeper flow through the upper fractured bedrock when the shallow groundwater flow system is modified. These results underscore that future site-specific applications of the base condition model require the input of site-specific data and recalibration to focus on the site of interest.

Minnesota↗
USGS1986

RAINFALL-LOSS PARAMETER ESTIMATION FOR ILLINOIS.

The U. S. Geological Survey is currently conducting an investigation to estimate values of parameters for two rainfall-loss computation methods used in a commonly used flood-hydrograph model. Estimates of six rainfall-loss parameters are required: four for the Exponential Loss-Rate method and two for the Initial and Uniform Loss-Rate method. Multiple regression analyses on calibrated data from 616 storms at 98 gaged basins are being used to develop parameter-estimating techniques for these six parameters at ungaged basins in Illinois. Parameter-estimating techniques are being verified using data from a total of 105 storms at 35 uncalibrated gaged basins.

Conference Paper↗
USGS2001

GCLAS: a graphical constituent loading analysis system

The U. S. Geological Survey has developed a program called GCLAS (Graphical Constituent Loading Analysis System) to aid in the computation of daily constituent loads transported in stream flow. Due to the relative paucity with which most water-quality data are collected, computation of daily constituent loads is moderately to highly dependent on human interpretation of the relation between stream hydraulics and constituent transport. GCLAS provides a visual environment for evaluating the relation between hydraulic and other covariate time series and the constituent chemograph. GCLAS replaces the computer program Sedcalc, which is the most recent USGS sanctioned tool for constructing sediment chemographs and computing suspended-sediment loads. Written in a portable language, GCLAS has an interactive graphical interface that permits easy entry of estimated values and provides new tools to aid in making those estimates. The use of a portable language for program development imparts a degree of computer platform independence that was difficult to obtain in the past, making implementation more straightforward within the USGS' s diverse computing environment. Some of the improvements introduced in GCLAS include (1) the ability to directly handle periods of zero or reverse flow, (2) the ability to analyze and apply coefficient adjustments to concentrations as a function of time, streamflow, or both, (3) the ability to compute discharges of constituents other than suspended sediment, (4) the ability to easily view data related to the chemograph at different levels of detail, and (5) the ability to readily display covariate time series data to provide enhanced visual cues for drawing the constituent chemograph.

Conference Paper↗
USGS2009

Advanced Tools for River Science: EAARL and MD_SWMS: Chapter 3

Disruption of flow regimes and sediment supplies, induced by anthropogenic or climatic factors, can produce dramatic alterations in river form, vegetation patterns, and associated habitat conditions. To improve habitat in these fluvial systems, resource managers may choose from a variety of treatments including flow and/or sediment prescriptions, vegetation management, or engineered approaches. Monitoring protocols developed to assess the morphologic response of these treatments require techniques that can measure topographic changes above and below the water surface efficiently, accurately, and in a standardized, cost-effective manner. Similarly, modeling of flow, sediment transport, habitat, and channel evolution requires characterization of river morphology for model input and verification. Recent developments by the U.S. Geological Survey with regard to both remotely sensed methods (the Experimental Advanced Airborne Research LiDAR; EAARL) and computational modeling software (the Multi-Dimensional Surface-Water Modeling System; MD_SWMS) have produced advanced tools for spatially explicit monitoring and modeling in aquatic environments. In this paper, we present a pilot study conducted along the Platte River, Nebraska, that demonstrates the combined use of these river science tools.

Report↗
USGS2000

Documentation of a computer program to simulate lake-aquifer interaction using the MODFLOW ground water flow model and the MOC3D solute-transport model

Heads and flow patterns in surficial aquifers can be strongly influenced by the presence of stationary surface-water bodies (lakes) that are in direct contact, vertically and laterally, with the aquifer. Conversely, lake stages can be significantly affected by the volume of water that seeps through the lakebed that separates the lake from the aquifer. For these reasons, a set of computer subroutines called the Lake Package (LAK3) was developed to represent lake/aquifer interaction in numerical simulations using the U.S. Geological Survey three-dimensional, finite-difference, modular ground-water flow model MODFLOW and the U.S. Geological Survey three-dimensional method-of-characteristics solute-transport model MOC3D. In the Lake Package described in this report, a lake is represented as a volume of space within the model grid which consists of inactive cells extending downward from the upper surface of the grid. Active model grid cells bordering this space, representing the adjacent aquifer, exchange water with the lake at a rate determined by the relative heads and by conductances that are based on grid cell dimensions, hydraulic conductivities of the aquifer material, and user-specified leakance distributions that represent the resistance to flow through the material of the lakebed. Parts of the lake may become "dry" as upper layers of the model are dewatered, with a concomitant reduction in lake surface area, and may subsequently rewet when aquifer heads rise. An empirical approximation has been encoded to simulate the rewetting of a lake that becomes completely dry. The variations of lake stages are determined by independent water budgets computed for each lake in the model grid. This lake budget process makes the package a simulator of the response of lake stage to hydraulic stresses applied to the aquifer. Implementation of a lake water budget requires input of parameters including those representing the rate of lake atmospheric recharge and evaporation, overland runoff, and the rate of any direct withdrawal from, or augmentation of, the lake volume. The lake/aquifer interaction may be simulated in both transient and steady-state flow conditions, and the user may specify that lake stages be computed explicitly, semi-implicitly, or fully-implicitly in transient simulations. The lakes, and all sources of water entering the lakes, may have solute concentrations associated with them for use in solute-transport simulations using MOC3D. The Stream Package of MODFLOW-2000 and MOC3D represents stream connections to lakes, either as inflows or outflows. Because lakes with irregular bathymetry can exist as separate pools of water at lower stages, that coalesce to become a single body of water at higher stages, logic was added to the Lake Package to allow the representation of this process as a user option. If this option is selected, a system of linked pools (sublakes) is identified in each time step and stages are equalized based on current relative sublake surface areas.

Water-Resources Investigations Report↗
USGS2024

Computation of bromide concentrations at the Kansas River at De Soto, Kansas, January 2021 through October 2023

The Kansas River is an essential water resource that provides drinking water to more than 950,000 people in northeastern Kansas. Water suppliers that rely on the Kansas River as a water-supply source use physical and chemical water-treatment strategies to remove contaminants before distribution. Water District No. 1 of Johnson County, Kansas (WaterOne), is the largest water supplier in the State and uses the Kansas and Missouri Rivers as water-supply sources to provide drinking water to the Kansas City metropolitan area. WaterOne has been using ozone disinfection as a primary water-treatment strategy since the summer of 2020. Water suppliers that rely on ozone disinfection have become increasingly concerned with the presence of elevated dissolved bromide (the negatively charged form of bromine; hereafter referred to as “bromide”) concentrations in their water-supply source. Ozone disinfection of source water containing elevated concentrations of bromide can lead to the formation of bromate, a regulated disinfection byproduct and probable carcinogen. Real-time computations of bromide concentrations upstream from the WaterOne source-water intake in the Kansas River can be used to assist WaterOne with proactive adjustment of water-treatment strategies. These computations can also be used to advance understanding of hydrologic processes affecting ozone disinfection and formation of bromate. This report documents the development of the surrogate-regression model that computes bromide concentrations in real time at De Soto, Kansas, and characterizes daily and monthly bromide concentrations at this location during the study period. The U.S. Geological Survey (USGS), in cooperation with WaterOne, collected specific conductance and discrete bromide sample data at the USGS streamgage Kansas River at De Soto, Kans. (06892350; hereafter referred to as “De Soto”), during January 2021 through October 2023 to develop a surrogate-regression model using ordinary least-squares regression that computes bromide concentrations at De Soto, which is about 15 miles upstream from the WaterOne source-water intake in the Kansas River. Specific conductance explained about 85 percent of the variance in bromide concentrations at De Soto during the study period. The surrogate-regression model documented in this report estimated that bromide concentrations at De Soto were likely to exceed the WaterOne water-treatment level of concern (150 micrograms per liter [μg/L]) when specific conductance was greater than or equal to about 930 microsiemens per centimeter at 25 degrees Celsius. Surrogate-regression model computations of bromide concentrations documented in this report are available at the USGS National Real-Time Water-Quality website ( https://nrtwq.usgs.gov/ ). Bromide concentrations in discrete samples ranged from 31.9 to 251 μg/L and exceeded the water-treatment level of concern in about 34 percent of the 41 samples collected at De Soto during January 2021 through October 2023. Computed daily bromide concentrations ranged from 38.2 to 277 μg/L and exceeded the water-treatment level of concern about 46 percent of the time during January 2021 through October 2023. Generally, an inverse relation was observed between bromide and streamflow during the study period. Higher bromide concentrations were observed during September through February, and lower bromide concentrations were observed during March through August. Seasonal median bromide concentrations were significantly different in all pairwise seasonal combinations, except for summer versus spring. Computed median bromide concentrations were highest during winter, followed by fall, then spring and summer.

Kansas↗
USGS2023

Colorado River Basin Actionable and Strategic Integrated Science and Technology (ASIST) pilot project progress toward an information management and technology plan

Executive Summary The U.S. Geological Survey carries out a wide variety of multidisciplinary science projects through the Bureau’s regions, mission areas, programs, and science centers. However, this structure can limit interactions among individual scientists, segregate data holdings, and make it difficult to apply holistic, interdisciplinary science. In addition, technological advances in sensors, data storage and analysis, computing power, and networking have resulted in an exponential growth in the volume, variety, and complexity of data. To address some of these challenges, the U.S. Geological Survey initiated the Colorado River Basin Actionable and Strategic Integrated Science and Technology (ASIST) pilot project to facilitate interdisciplinary science in the drought-stricken basin and apply information management and technology (IMT) resources that can be used to deliver actionable science efficiently and effectively. In fiscal year 2021, the Data Management and Advanced Technology subgroup of the ASIST pilot project worked toward developing an IMT plan that includes several advanced IMT solutions that are being implemented Bureau-wide by the Office of the Associate Chief Information Officer. This plan identifies applications, opportunities, and steps to leverage new and existing technologies, data, models, and knowledge to support integrated science projects across the Colorado River Basin. The subgroup also created an inventory of available IMT resources and their locations. The Colorado River Basin ASIST pilot project also developed a multiyear approach to build capacity for supporting integrated science projects in the Colorado River Basin, which provides an advanced IMT framework for expediting the production of interdisciplinary science related to the basin.

Colorado River basin↗
USGS1977

Maps showing ground-water conditions in the southern part of the Black Mesa area, Navajo, Apache, and Coconino Counties, Arizona, 1976

The southern part of the Black Mesa area includes about 2,500 mi 2 in northeastern Arizona and is entirely in the Navajo and Hopi Indian Reservations. The main source of water is the ground water in the several aquifers that are made up of one or more formations. The aquifers are stacked one on the other and generally are not hydraulically connected; the composite stratigraphic column indicates the relative position of the formations. The main waterbearing units are the N and D aquifers, the Toreva and Wepo Formations, and the alluvium. The geologic structure and topographic relief preclude a uniform depth to water in the area; therefore, recommended drilling depths should be determined on an individual site basis. Ground-water development has been mainly for public, domestic, and livestock supplies, In 1975 about 500 acre-ft of ground water was withdrawn from the aquifers in the southern part of the black Mesa area; mo st of the water was from the N aquifer. In 1951-76-the period for which data were used to compile these maps-withdrawals from the N aquifer resulted in water-level declines in parts of the area . Measurable changes in water levels have not occurred in the other aquifers in the 25-year period. The hydrologic data on which these maps are based are available, for the most part, in computer-printout form for consultation at the Arizona Water Commission, 222 North Central Avenue, Suite 800, Phoenix, and at U.S. Geological Survey offices in: Federal Building, 301 West Congress Street, Tucson; Valley Center, Suite 1880, Phoenix; and 2255 North Gemini Drive, Building 3, Flagstaff. Material from which copies can be made at private expense is available at the Tucson, Phoenix, and Flagstaff offices of the U.S. Geological Survey.

Arizona↗
USGS2000

A seismic landslide susceptibility rating of geologic units based on analysis of characterstics of landslides triggered by the 17 January, 1994 Northridge, California earthquake

One of the most significant effects of the 17 January, 1994 Northridge, California earthquake ( M =6.7) was the triggering of thousands of landslides over a broad area. Some of these landslides damaged and destroyed homes and other structures, blocked roads, disrupted pipelines, and caused other serious damage. Analysis of the distribution and characteristics of these landslides is important in understanding what areas may be susceptible to landsliding in future earthquakes. We analyzed the frequency, distribution, and geometries of triggered landslides in the Santa Susana 7.5′ quadrangle, an area of intense seismic landslide activity near the earthquake epicenter. Landslides occurred primarily in young (Late Miocene through Pleistocene) uncemented or very weakly cemented sediment that has been repeatedly folded, faulted, and uplifted in the past 1.5 million years. The most common types of landslide triggered by the earthquake were highly disrupted, shallow falls and slides of rock and debris. Far less numerous were deeper, more coherent slumps and block slides, primarily occurring in more cohesive or competent materials. The landslides in the Santa Susana quadrangle were divided into two samples: single landslides (1502) and landslide complexes (60), which involved multiple coalescing failures of surficial material. We described landslide morphologies by computing simple morphometric parameters (area, length, width, aspect ratio, slope angle). To quantify and rank the relative susceptibility of each geologic unit to seismic landsliding, we calculated two indices: (1) the susceptibility index, which is the ratio (given as a percentage) of the area covered by landslide sources within a geologic unit to the total outcrop area of that unit; and (2) the frequency index [given in landslides per square kilometer (ls/km 2 )], which is the total number of landslides within each geologic unit divided by the outcrop area of that unit. Susceptibility categories include very high (>2.5% landslide area or >30 ls/km 2 ), high (1.0–2.5% landslide area or 10–30 ls/km 2 ), moderate (0.5–1.0% landslide area or 3–10 ls/km 2 ), and low (<0.5% landslide area and <3 ls/km 2 ).

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