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A regional groundwater flow model (https://pubs.usgs.gov/sir/2009/5244/) was updated to reflect 2017 pumping conditions in the Tri-County Region covering most of Clinton, Eaton, and Ingham Counties, Michigan. This model was developed to simulate the regional hydrologic system in Tri-County area and continues to be used for planning and protection of area water supplies. Revised contributing area delineations in response to recent pumping conditions were needed for local wellhead protection area programs. The model was calibrated to water level observations for 2017 from well driller logs, average water levels for 2012-17 from active USGS observation wells, and estimated baseflow for 2012-16 from USGS streamgaging...
This data release contains model simulation results of a particle tracking analysis to delineate areas that provide recharge to surface waters and public-supply wells on Long Island, NY. The analysis partitions the recharge areas based on particle travel times of greater than or less than 10 years to reach the receiving surface water or well. The simulation was performed using a regional-scale numerical model of the Long Island aquifer system (Walter and others, 2020a and 2020b) for average 2005-2015 conditions. The model implements MODFLOW-NWT (Niswonger and others, 2011) to represent steady-state groundwater pumping and aquifer recharge conditions; recharge areas were identified and partitioned using the particle-tracking...
In cooperation with the U.S. Navy, USGS developed and calibrated a numerical MODFLOW 6 model to simulate regional groundwater flow under selected conditions during 1999-2017 at and near the former Willow Grove Naval Air Station Joint Reserve Base in Horsham, Montgomery County and the former Naval Air Warfare Center Warminster in Bucks County, Pennsylvania. The model simulations provide information on regional groundwater-flow paths and groundwater/surface-water exchanges, in relation to changes in water supply pumping and recharge rates. Groundwater flow paths were simulated using MODPATH 7 from possible PFAS sources at the former bases under steady-state conditions for years 1999, 2010, 2013, 2016, and 2017. This...
A previously developed three-dimensional steady-state groundwater flow model (https://doi.org/10.3133/sir20205091) is used to assist resource managers and planners in developing informed strategies to address nitrogen loading to coastal water bodies of Long Island, New York. Coastal water bodies of Long Island are important economic and recreational resources for the region. Therefore, the U.S. Geological Survey and New York State Department of Environmental Conservation initiated a program to delineate a comprehensive dataset of CAs (or areas contributing groundwater), travel times, and groundwater discharges to streams, lakes, marine-surface waters, and subsea discharge boundaries. The 25-layer regional groundwater-flow...
A regional groundwater-flow model and particle-tracking program were used to delineate areas contributing groundwater to coastal and freshwater bodies and to estimate travel times from the water table to saline water bodies under average conditions from 1968 to 1983 on Long Island, New York. The coastal waters of Long Island are important economic and recreational resources for the region. The coastal water bodies receive freshwater from inflow of both surface water and groundwater, in addition to tidal exchanges of saltwater. Excessive nitrogen inputs associated with development and urbanization in the freshwater recharge areas to coastal water bodies can adversely affect marine and estuarine ecosystems. The results...
This data release contains model input and output files for simulating and predicting thermal spring flows at Hot Springs National Park (HOSP), Hot Springs, Arkansas. A three-dimensional hydrogeologic framework of the Hot Springs anticlinorium beneath Hot Springs National Park was constructed to represent the complex hydrogeology of HOSP and surrounding areas to depths exceeding 9,000 feet below ground surface. The framework, composed of 6 rock formations and 1 vertical fault emplaced beneath the thermal springs, was discretized into 19 layers, 429 rows, and 576 columns and incorporated into a 3-dimensional steady-state groundwater-flow model constructed in MODFLOW-2005. Historical daily mean thermal spring flows...
A three-dimensional groundwater flow model using MODFLOW 6 (version 6.2.2) was developed and calibrated for unconsolidated Coastal Plain aquifers underlying the Joint Base McGuire-Dix-Lakehurst (JBMDL) and vicinity, New Jersey, to evaluate groundwater flow pathways of per- and polyfluoroalkyl substances (PFAS) contamination associated with use of aqueous film forming foam (AFFF). The model was developed and calibrated by the U.S. Geological Survey (USGS) in cooperation with the U.S. Air Force Civil Engineer Center (AFCEC) based on the previously developed hydrogeologic framework (https://doi.org/10.3133/ofr20191134). Steady-state flow in the unconsolidated aquifers was simulated using the MODFLOW 6 which accounts...
A three-dimensional groundwater-flow model of a 73.2 square mile area in southeastern Albuquerque, New Mexico was designed and coupled to a regional (parent) model of the Middle Rio Grande Basin with the local-grid refinement numerical code MODFLOW-LGR2. This fine-gridded local (child) model was designed to simulate the response of the aquifer to pumping stresses and simulate advective groundwater flow. The child model was calibrated by inverse modeling by nonlinear regression (UCODE_2005) for 1949 to 2013 conditions, the period for which observation data was most complete and reliable. The simulation period spanned from predevelopment to future conditions (1900 to 2050). As part of an effort to protect the source...
Three groundwater flow models, using MODFLOW-2000, SEAWAT, and SHARP model codes, were used to evaluate plans to supply potable and non-potable water to residents and businesses of Cape May County, New Jersey until at least 2050. The ideal plan would meet projected demands and minimize adverse effects on currently used sources of potable, non- potable, and ecological water supplies. The U.S. Geological Survey used two previously developed groundwater flow models, as well as a newly developed groundwater flow model, to evaluate the shallow and deep aquifer systems in Cape May County. The groundwater flow in the shallow and deep aquifer systems of Cape May County were simulated separately. Flow in the shallow aquifers...
In 2016, the United States Geological Survey (USGS) began development of a regional-scale numerical model of the Long Island aquifer system, as part of the National Water Quality Assessment (NAWQA) Program. The three-dimensional groundwater-flow model was developed to evaluate 1) responses of the hydrologic system to changes in natural and anthropogenic hydraulic stresses 2) the subsurface distribution of groundwater age, and 3) the regional-scale distribution of groundwater travel times and the source of water to fresh surface waters and coastal receiving waters. The model also provides the groundwater flow components used to define model boundaries for possible inset models used for local-scale analyses. Unconsolidated...
An existing three-dimensional model (MODFLOW-2000) by Petkewich and Campbell (2007) was updated to simulate potential changes in groundwater flow and groundwater-level conditions caused by injecting reclaimed water into the Middendorf aquifer in Mount Pleasant, South Carolina. The model was recalibrated to conditions from 1900 to 2008. Simulations included a Base Case and two injection scenarios. Maximum pumping rates were simulated as 6.65, 8.50, and 10.5 million gallons per day for the Base Case, Scenario 1, and Scenario 2, respectively. The Base Case simulation represents a non-injection estimate of the year 2050 groundwater levels for comparison purposes for the two injection scenarios. For Scenarios 1 and 2,...
MODFLOW-NWT groundwater flow models and MODPATH6 particle tracking simulations were developed to determine contributing areas (CAs) for and advective travel times to domestic wells under extreme recharge events in a small hypothetical watershed underlain by dipping sedimentary rocks. The hypothetical models are based on hydrogeologic conditions in the Newark Basin, located in New Jersey, New York, and Pennsylvania, USA. During extreme recharge events, groundwater supply wells have increased vulnerability to contaminants or pathogens originating at land surface that are flushed into the subsurface. Fractured-rock aquifers are particularly vulnerable because transport to wells can be very fast owing to preferential...
The U. S. Geological Survey, in cooperation with the U.S. Environmental Protection Agency, developed a numerical ground-water-flow model, using MODFLOW-2000, to simulate ground-water flow in the Pohatcong Valley including the area within the Pohatcong Valley Ground Water Contamination Site. In 1978, the chlorinated solvents trichloroethene (TCE) and tetrachloroethene (PCE) were detected in thePohatcong Valley in production wells in Washington Borough and Washington Township, Warren County, New Jersey. Subsequent investigation revealed that many domestic wells in Washington and Franklin Townships also were contaminated, and in 1989 the Pohatcong Valley Ground Water Contamination Site was added to the U.S. Environmental...
A previously constructed numerical model (https://pubs.usgs.gov/pp/2007/1737a/) simulating the regional groundwater-flow system in the vicinity of the Wright-Patterson Air Force Base (WPAFB) near Dayton, Ohio, was updated to incorporate current hydrologic stresses and conditions and improve the usefulness of the model for water-supply planning and protection. The Great Miami Buried Valley Aquifer was designated a sole-source aquifer in 1988 and provides the supply for the substantial water use needs in the Dayton area. Hydrogeologic investigations of groundwater flow in the nearby WPAFB have been ongoing since the early 1990s, when the USGS first partnered with WPAFB to model groundwater flow near the Base in an...
The U.S. Geological Survey, in cooperation with Aiken County; City of Aiken; Breezy Hill Water and Sewer Company, Inc.; Montmorenci-Couchton Water and Sewer District, Inc.; and Gilbert-Summit Rural Water District developed a model for use with MODFLOW-NWT and MODPATH5 to evaluate groundwater flow and advective transport under pre- and post-development conditions in the Atlantic Coastal Plain (ACP) and bedrock crystalline-rock aquifer in the Aiken County, SC area. Groundwater availability, geochemistry, and flow pathways to public-supply wells (PSW) were assessed between 2015 and 2019. A population increase by about 17.6 percent from 2000 to 2015 in Aiken County, as well as the current (2022) and potential economic...
A three-dimensional, groundwater-flow model (MODFLOW-2000) and a particle-tracking program (MODPATH5) were used to evaluate the effects of changes in pumping on regional groundwater-flow paths, 2005 and 2010, and areas contributing recharge to discharging wells, 1990-2010, in the vicinity of North Penn Area 7 Superfund site, Montgomery County, Pennsylvania. The steady-state model was used to simulate conditions for No Pumping, 1990, 2000, 2005, and 2010. The model was used to (1) evaluate the changes in flow paths from likely contaminant sources, and (2) delineate areas contributing recharge to streams and pumping wells. This USGS data release contains all of the input and output files for the simulations described...
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