Richard G Niswonger
Biography
Our research aims to better understand local and regional hydrologic processes affecting humans and the environment. Our focus is on the development of numerical software for simulating coupled hydrologic and anthropogenic effects on water resources. An example of the software we develop is the integrated groundwater and surface water model, GSFLOW that can simulate all of the important terrestrial hydrologic processes in watersheds. We combine GSFLOW with other software and diverse data types, including satellite imagery, geo-spatial data sets, hydrologic tracers and age dating, and many other quantitative and qualitative information that provides skill for hydrologic prediction.
Science and Products
Water for the Seasons
Water for the Seasons (WftS) is a four year study funded by the National Science Foundation and the U.S. Department of Agriculture. WtfS uses the Truckee-Carson River System (TCRS) as a pilot study to learn how to best link science with decision-making in snow-fed arid-land...
Water Resources Discipline Research Seminar Series
The Water Resources Discipline (predecessor of the Water Mission Area) Research Seminar Series hosted a wide range of speakers on a diverse array of water research topics. Archived videos of many seminars are available for viewing.
Managed aquifer recharge in snow-fed river basins: What, why and how?
What does climate change mean for snow-fed river basins?Climate change poses unique challenges in snow-fed river basins across the western United States because the majority of water supply originates as snow (Dettinger, Udall, & Georgakakos, 2015). In the Sierra Nevada, recent observations include changes in snow accumulation and snowmelt,...
Sterle, Kelley; Kitlasten, Wesley; Morway, Eric D.; Niswonger, Richard G.; Singletary, Loretta Linkages between hydrology and seasonal variations of nutrients and periphyton in a large oligotrophic subalpine lake
Periphyton is important to lake ecosystems, contributing to primary production, nutrient cycling, and benthic metabolism. Increases in periphyton growth in lakes can be indicative of changes in water quality, shifts in ecosystem structure, and increases in nutrient fluxes. In oligotrophic lakes, conservationists are interested in characterizing...
Niswonger, Richard G.; Smith, David; Rosenberry, Donald O.; Sudeep Chandra; Naranjo, Ramon C.; Niswonger, Richard G.; Smith, David; Rosenberry, Donald O.; Chandra, Sudeep GSFLOW-GRASS v1.0.0: GIS-enabled hydrologic modeling of coupled groundwater–surface-water systems
The importance of water moving between the atmosphere and aquifers has led to efforts to develop and maintain coupled models of surface water and groundwater. However, developing inputs to these models is usually time-consuming and requires extensive knowledge of software engineering, often prohibiting their use by many researchers and water...
Ng, G.-H. Crystal; Wickert, Andrew D.; Somers, Lauren D.; Saberi, Leila; Cronkite-Ratcliff, Collin; Niswonger, Richard G.; McKenzie, Jeffrey M. Input data processing tools for the integrated hydrologic model GSFLOW
Integrated hydrologic modeling (IHM) encompasses a vast number of processes and specifications, variable in time and space, and development of models can be arduous. Model input construction techniques have not been formalized or made easily reproducible. Creating the input files for integrated hydrologic models requires complex GIS...
Gardner, Murphy A.; Morton, Charles G.; Huntington, Justin L.; Niswonger, Richard G.; Henson, Wesley R.
Documentation for the MODFLOW 6 Groundwater Flow Model
This report documents the Groundwater Flow (GWF) Model for a new version of MODFLOW called MODFLOW 6. The GWF Model for MODFLOW 6 is based on a generalized control-volume finite-difference approach in which a cell can be hydraulically connected to any number of surrounding cells. Users can define the model grid using one of three discretization...
Langevin, Christian D.; Hughes, Joseph D.; Banta, Edward R.; Niswonger, Richard G.; Panday, Sorab; Provost, Alden M. Managed aquifer recharge through off-season irrigation in agricultural regions
Options for increasing reservoir storage in developed regions are limited and prohibitively expensive. Projected increases in demand call for new long-term water storage to help sustain agriculture, municipalities, industry, and ecological services. Managed aquifer recharge (MAR) is becoming an integral component of water resources around the...
Niswonger, Richard G.; Morway, Eric D.; Triana, Enrique; Huntington, Justin L. Evaluating mountain meadow groundwater response to Pinyon-Juniper and temperature in a great basin watershed
This research highlights development and application of an integrated hydrologic model (GSFLOW) to a semiarid, snow-dominated watershed in the Great Basin to evaluate Pinyon-Juniper (PJ) and temperature controls on mountain meadow shallow groundwater. The work used Google Earth Engine Landsat satellite and gridded climate archives for model...
Carroll, Rosemary W.H.; Huntington, Justin L.; Snyder, Keirith A.; Niswonger, Richard G.; Morton, Charles; Stringham, Tamzen K. Nutrient processes at the stream-lake interface for a channelized versus unmodified stream mouth
Inorganic forms of nitrogen and phosphorous impact freshwater lakes by stimulating primary production and affecting water quality and ecosystem health. Communities around the world are motivated to sustain and restore freshwater resources and are interested in processes controlling nutrient inputs. We studied the environment where streams flow...
Niswonger, Richard G.; Naranjo, Ramon C.; Smith, David; Constantz, James E.; Allander, Kip K.; Rosenberry, Donald O.; Neilson, Bethany; Rosen, Michael R.; Stonestrom, David A. Assessing the role of climate and resource management on groundwater dependent ecosystem changes in arid environments with the Landsat archive
Groundwater dependent ecosystems (GDEs) rely on near-surface groundwater. These systems are receiving more attention with rising air temperature, prolonged drought, and where groundwater pumping captures natural groundwater discharge for anthropogenic use. Phreatophyte shrublands, meadows, and riparian areas are GDEs that provide critical habitat...
Huntington, Justin; McGwire, Kenneth C.; Morton, Charles; Snyder, Keirith A.; Peterson, Sarah; Erickson, Tyler; Niswonger, Richard G.; Carroll, Rosemary W.H.; Smith, Guy; Allen, Richard Toward improved simulation of river operations through integration with a hydrologic model
Advanced modeling tools are needed for informed water resources planning and management. Two classes of modeling tools are often used to this end–(1) distributed-parameter hydrologic models for quantifying supply and (2) river-operation models for sorting out demands under rule-based systems such as the prior-appropriation doctrine. Within...
Morway, Eric D.; Niswonger, Richard G.; Triana, Enrique An overview of current applications, challenges, and future trends in distributed process-based models in hydrology
Process-based hydrological models have a long history dating back to the 1960s. Criticized by some as over-parameterized, overly complex, and difficult to use, a more nuanced view is that these tools are necessary in many situations and, in a certain class of problems, they are the most appropriate type of hydrological model. This is especially...
Fatichi, Simone; Vivoni, Enrique R.; Odgen, Fred L; Ivanov, Valeriy Y; Mirus, Benjamin B.; Gochis, David; Downer, Charles W; Camporese, Matteo; Davison, Jason H; Ebel, Brian A.; Jones, Norm; Kim, Jongho; Mascaro, Giuseppe; Niswonger, Richard G.; Restrepo, Pedro; Rigon, Riccardo; Shen, Chaopeng; Sulis, Mauro; Tarboton, David Groundwater exchanges near a channelized versus unmodified stream mouth discharging to a subalpine lake
The terminus of a stream flowing into a larger river, pond, lake, or reservoir is referred to as the stream-mouth reach or simply the stream mouth. The terminus is often characterized by rapidly changing thermal and hydraulic conditions that result in abrupt shifts in surface water/groundwater (sw/gw) exchange patterns, creating the...
Constantz, James; Naranjo, Ramon C.; Niswonger, Richard G.; Allander, Kip K.; Neilson, B.; Rosenberry, Donald O.; Smith, David W.; Rosecrans, C.; Stonestrom, David A.
GSFLOW: Coupled Groundwater and Surface-Water Flow Model
Groundwater and Surface-water FLOW (GSFLOW) was developed to simulate coupled groundwater and surface-water resources. The model is based on the integration of the U.S. Geological Survey Precipitation-Runoff Modeling System (PRMS) and the U.S. Geological Survey Modular Groundwater Flow Model (MODFLOW).
MODFLOW-NWT: A Newton Formulation for MODFLOW-2005
MODFLOW-NWT is a Newton-Raphson formulation for MODFLOW-2005 to improve solution of unconfined groundwater-flow problems. MODFLOW-NWT is a standalone program that is intended for solving problems involving drying and rewetting nonlinearities of the unconfined groundwater-flow equation.
CRT: Cascade Routing Tool to Define and Visualize Flow Paths for Grid-Based Watershed Models
The U.S. Geological Survey Cascade Routing Tool (CRT) is a computer application for watershed models that include the coupled Groundwater and Surface-water FLOW model GSFLOW and the Precipitation-Runoff Modeling System (PRMS). CRT generates output to define cascading surface and shallow subsurface flow paths for grid-based model domains.