Filters: partyWithName: Michael N. Fienen (X)
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A new groundwater flow model for western Chippewa County, Wisconsin has been developed by the Wisconsin Geological and Natural History Survey (WGNHS) and the U.S. Geological Survey (USGS). An analytic element GFLOW model was constructed and calibrated to generate hydraulic boundary conditions for the perimeter of the more detailed three-dimensional MODFLOW-NWT model. This three-dimensional model uses the USGS MODFLOW-NWT finite difference code, a standalone version of MODFLOW-2005 that incorporates the Newton (NWT) solver. The model conceptualizes the hydrogeology of western Chippewa County as a six-layer system which includes several hydrostratigraphic units. The model explicitly simulates groundwater-surface-water...
A groundwater-flow model was developed for the Bad River Watershed and surrounding area by using the U.S. Geological Survey (USGS) finite-difference code MODFLOW–NWT. The model simulates steady-state groundwater-flow and base flow in streams by using the streamflow routing (SFR) package. The model was calibrated to groundwater levels and base flows obtained from the USGS National Water Information System (NWIS) database, and groundwater levels obtained from the Wisconsin Department of Natural Resources and Bad River Band well-construction databases. Calibration was performed via nonlinear regression by using the parameter-estimation software suite PEST.
Abstract: We used a numerical model to investigate how a barrier island groundwater system responds to increases of up to 60 cm in sea level. We found that a sea-level rise of 20 cm leads to substantial changes in the depth of the water table and the extent and depth of saltwater intrusion, which are key determinants in the establishment, distribution and succession of vegetation assemblages and habitat suitability in barrier islands ecosystems. In our simulations, increases in water-table height in areas with a shallow depth to water (or thin vadose zone) resulted in extensive groundwater inundation of land surface and a thinning of the underlying freshwater lens. We demonstrated the interdependence of the groundwater...
Categories: Publication;
Types: Citation;
Tags: Ecohydrology,
Northeast CASC,
Sea-Level Rise and Coasts,
Water, Coasts and Ice,
Wetlands,
The Little Plover River groundwater flow model simulates three-dimensional groundwater movement in and around Wisconsin’s Little Plover River basin under steady-state and transient conditions. The groundwater flow model uses the U.S. Geological Survey’s MODFLOW-NWT modeling code. 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...
Hypothetical two-dimensional, steady-state groundwater flow models of a previously published 1988 model calibration exercise were developed using the finite-difference computer code, MODFLOW-2005, to demonstrate the power of modern parameter estimation and uncertainty approaches. For this study, an initial run recreated the 1988 "truth" model. The true model was then simplified to account for information not provided the participants in the 1988 calibration exercise. Increasing sophistication was brought to bear to demonstrate how problems identified in 1988 were overcome using modern software approaches. This USGS data release contains all of the input and output to run the model simulations described in the associated...
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...
The U.S. Geological Survey, in cooperation with the Air Force Civil Engineer Center, developed a numerical, steady-state regional model, using MODFLOW-2005, to evaluate current (2010) conditions and the potential effects of future (2030) groundwater withdrawals on water levels, streamflows, hydraulic gradients, and advective transport near the Joint Base Cape Cod (JBCC). Two numerical models were used in this analysis. An existing two-dimensional (one layer) model (termed the “coast model”), developed as part of a previous investigation of the potential effects of sea-level rise on the Cape Cod aquifer system (https://doi.org/10.3133/sir20165058), simulates the position of the freshwater/saltwater interface by using...
A three-dimensional, groundwater flow model was developed with the numerical code MODFLOW-NWT to represent changes in groundwater pumping and aquifer recharge in the Northern Atlantic Coastal Plain aquifer system from Long Island, New York to North Carolina. The model was constructed using existing hydrogeologic and geospatial information to represent the aquifer system geometry, boundaries, and hydraulic properties of the 19 separate regional aquifers and confining units within the aquifer system. The model was calibrated using an inverse modeling parameter-estimation (PEST) technique to conditions from 1986 to 2008, the period for which data are most complete and reliable. The simulation period for this analysis...
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