Richard G Niswonger
Richard Niswonger is a Research Hydrologist with the USGS Water Resources Mission Area.
We study local and regional water resources to aid water management decisions by developing software and constructing models that simulate both natural hydrologic processes and human water usage.
In my current role as the national water use research manager, I lead teams in the development of nationally consistent models with three key features: automated data retrieval, monthly simulation at the USGS 12-digit Watershed Boundary Dataset (HUC12) resolution, and periodic updates for current and forecasted results. These models help identify data gaps, enhance data collection, and refine water use predictions. They facilitate frequent reporting, synthesis, and interpretation of data that support communities making informed water resources decisions.
Science and Products
Decoupled application of the integrated hydrologic model, GSFLOW, to estimate agricultural irrigation in the Santa Rosa Plain, California
MODFLOW-NWT, a Newton formulation for MODFLOW-2005
Comment on "Evaluating interactions between groundwater and vadose zone using the HYDRUS-based flow package for MODFLOW" by Navin Kumar C. Twarakavi, Jirka Šimůnek and Sophia Seo
GSFLOW - Coupled Ground-Water and Surface-Water Flow Model Based on the Integration of the Precipitation-Runoff Modeling System (PRMS) and the Modular Ground-Water Flow Model (MODFLOW-2005)
Influence of perched groundwater on base flow
Method for estimating spatially variable seepage loss and hydraulic conductivity in intermittent and ephemeral streams
Streambed infiltration and ground-water flow from the Trout Creek drainage, an intermittent tributary to the Humboldt River, north-central Nevada
Documentation of the Unsaturated-Zone Flow (UZF1) Package for modeling Unsaturated Flow Between the Land Surface and the Water Table with MODFLOW-2005
Trends in streamflow on the Humboldt River between Elko and Imlay, Nevada, 1950-99
River-aquifer interactions, geologic heterogeneity, and low-flow management
Incorporating seepage losses into the unsteady streamflow equations for simulating intermittent flow along mountain front streams
Documentation of the Streamflow-Routing (SFR2) Package to Include Unsaturated Flow Beneath Streams - A Modification to SFR1
Science and Products
- Publications
Filter Total Items: 52
Decoupled application of the integrated hydrologic model, GSFLOW, to estimate agricultural irrigation in the Santa Rosa Plain, California
No abstract available.AuthorsJoseph A. Hevesi, Linda R. Woolfenden, Richard G. Niswonger, R. Steven Regan, Tracy NishikawaMODFLOW-NWT, a Newton formulation for MODFLOW-2005
This report documents a Newton formulation of MODFLOW-2005, called MODFLOW-NWT. MODFLOW-NWT is a standalone program that is intended for solving problems involving drying and rewetting nonlinearities of the unconfined groundwater-flow equation. MODFLOW-NWT must be used with the Upstream-Weighting (UPW) Package for calculating intercell conductances in a different manner than is done in the Block-CAuthorsRichard G. Niswonger, Sorab Panday, Motomu IbarakiComment on "Evaluating interactions between groundwater and vadose zone using the HYDRUS-based flow package for MODFLOW" by Navin Kumar C. Twarakavi, Jirka Šimůnek and Sophia Seo
Twarakavi et al (2008) compared four packages that can be used to estimate recharge for regional-scale groundwater flow simulations using MODFLOW (Harbaugh, 2005). This comment is focused on the comparisons made between two of these packages, namely, UZF1 (Niswonger et al., 2006) and a derivative of HYDRUS referred to herein as HYDRUS (Seo et al., 2007). In their paper, Twarakavi et al. (2008) staAuthorsR.G. Niswonger, David E. PrudicGSFLOW - Coupled Ground-Water and Surface-Water Flow Model Based on the Integration of the Precipitation-Runoff Modeling System (PRMS) and the Modular Ground-Water Flow Model (MODFLOW-2005)
The need to assess the effects of variability in climate, biota, geology, and human activities on water availability and flow requires the development of models that couple two or more components of the hydrologic cycle. An integrated hydrologic model called GSFLOW (Ground-water and Surface-water FLOW) was developed to simulate coupled ground-water and surface-water resources. The new model is basAuthorsSteven L. Markstrom, Richard G. Niswonger, R. Steven Regan, David E. Prudic, Paul M. BarlowInfluence of perched groundwater on base flow
Analysis with a three‐dimensional variably saturated groundwater flow model provides a basic understanding of the interplay between streams and perched groundwater. A simplified, layered model of heterogeneity was used to explore these relationships. Base flow contribution from perched groundwater was evaluated with regard to varying hydrogeologic conditions, including the size and location of theAuthorsRichard G. Niswonger, Graham E. FoggMethod for estimating spatially variable seepage loss and hydraulic conductivity in intermittent and ephemeral streams
A method is presented for estimating seepage loss and streambed hydraulic conductivity along intermittent and ephemeral streams using streamflow front velocities in initially dry channels. The method uses the kinematic wave equation for routing streamflow in channels coupled to Philip's equation for infiltration. The coupled model considers variations in seepage loss both across and along the chanAuthorsR.G. Niswonger, David E. Prudic, G.E. Fogg, David A. Stonestrom, E.M. BucklandStreambed infiltration and ground-water flow from the Trout Creek drainage, an intermittent tributary to the Humboldt River, north-central Nevada
Ground water is abundant in many alluvial basins of the Basin and Range Physiographic Province of the western United States. Water enters these basins by infiltration along intermittent and ephemeral channels, which originate in the mountainous regions before crossing alluvial fans and piedmont alluvial plains. Water also enters the basins as subsurface ground-water flow directly from the mountainAuthorsDavid E. Prudic, Richard G. Niswonger, James R. Harrill, James L. WoodDocumentation of the Unsaturated-Zone Flow (UZF1) Package for modeling Unsaturated Flow Between the Land Surface and the Water Table with MODFLOW-2005
Percolation of precipitation through unsaturated zones is important for recharge of ground water. Rain and snowmelt at land surface are partitioned into different pathways including runoff, infiltration, evapotranspiration, unsaturated-zone storage, and recharge. A new package for MODFLOW-2005 called the Unsaturated-Zone Flow (UZF1) Package was developed to simulate water flow and storage in the uAuthorsRichard G. Niswonger, David E. Prudic, R. Steven ReganTrends in streamflow on the Humboldt River between Elko and Imlay, Nevada, 1950-99
No abstract available.AuthorsDavid E. Prudic, Richard G. Niswonger, Russell W. PlumeRiver-aquifer interactions, geologic heterogeneity, and low-flow management
Low river flows are commonly controlled by river-aquifer exchange, the magnitude of which is governed by hydraulic properties of both aquifer and aquitard materials beneath the river. Low flows are often important ecologically. Numerical simulations were used to assess how textural heterogeneity of an alluvial system influences river seepage and low flows. The Cosumnes River in California was usedAuthorsJ.H. Fleckenstein, R.G. Niswonger, G.E. FoggIncorporating seepage losses into the unsteady streamflow equations for simulating intermittent flow along mountain front streams
Seepage losses along numerous mountain front streams that discharge intermittently onto alluvial fans and piedmont alluvial plains are an important source of groundwater in the Basin and Range Province of the Western United States. Determining the distribution of seepage loss along mountain front streams is important when assessing groundwater resources of the region. Seepage loss along a mountainAuthorsR.G. Niswonger, David E. Prudic, G. Pohll, J. ConstantzDocumentation of the Streamflow-Routing (SFR2) Package to Include Unsaturated Flow Beneath Streams - A Modification to SFR1
Many streams in the United States, especially those in semiarid regions, have reaches that are hydraulically disconnected from underlying aquifers. Ground-water withdrawals have decreased water levels in valley aquifers beneath streams, increasing the occurrence of disconnected streams and aquifers. The U.S. Geological Survey modular ground-water model (MODFLOW-2000) can be used to model these intAuthorsRichard G. Niswonger, David E. Prudic - Science
- Data
- Software
- Multimedia