Robert S Regan
Research, development and application of the PRMS, GSFLOW, and MODSIM-GSFLOW modeling codes and National Hydrologic Modeling Infrastructure
PRESENT ADDRESS:
U.S. Geological Survey
Denver Federal Center, Box 25046, MS 412
Denver, Colorado 80225
EDUCATION:
Masters of Divinity (2000). Wesley Theological Seminary, Washington, D.C.
BA Environmental Science (1987). University of Virginia, Charlottesville, Virginia,
PRESENT ASSIGNMENT:
DATES From: 2003 To: Present
DESCRIPTION: Research, development, and applications focuses on incorporating new simulation algorithms and enhancements of existing algorithms within the Precipitation-Runoff Modeling System (PRMS), the coupled Modular Groundwater Flow Model (MODFLOW) and PRMS simulation model—GSFLOW, the coupled MODSIM-GSFLOW simulation code, and the National Hydrologic Modeling (NHM) Infrastructure. Development is driven by WMA research objectives of improving the understanding and simulation of watershed-scale hydrologic processes to climate and anthropogenic influences, environmental characteristics with input and requests from USGS and other Federal agencies, the academic community, and private sector scientists.
RELEVANT EXPERIENCE:
Research and development of the PRMS simulation model, most recently developing methods for input of historic and projected climate; dynamic parameters; and water-use information and enhancement of surface-depression storage and spatial and temporal characterization of model parameters for use in large model domains.
Research and development of the coupled groundwater/surface-water simulation model (GSFLOW) and MODFLOW UZF and AG Package, and MODSIM-GSFLOW coupled simulation code.
Research and development of a loosely-coupled, sub-daily simulation model using PRMS, NOAA-NWS Lag and K river routing model, and USACE HEC-ResSim Reservoir System Simulation model for a large watershed spanning portions of NY, NJ, and PA.
Hydrologist, member of the Modeling of Watershed Systems (MoWS) project, USGS National Research Program, Central Region, Lakewood, Colorado (2003-2016)
Senior Pastor, Greenwood United Methodist Church, Winchester, Virginia (1999-2002)
Hydrologist, project chief and member of the Hydrologic Analysis Software Support Section, Reston, Virginia (1992-1996)
Computer Scientist, project chief and site admistrator USGS National Research Program, Northeast Region, Office of Surface Water, Office of Groundwater, and Office of Water Quality, Reston, Virginia (1986-1992)
Hydrologist, member of the Modeling of Hydrodynamic Systems project, USGS National Research Program, Northeast Region, Reston, Virginia (1981-1986)
Science and Products
PRMS-IV, the precipitation-runoff modeling system, version 4
Simulation of climate-change effects on streamflow, lake water budgets, and stream temperature using GSFLOW and SNTEMP, Trout Lake Watershed, Wisconsin
Application of the Precipitation-Runoff Modeling System (PRMS) in the Apalachicola-Chattahoochee-Flint River Basin in the southeastern United States
CRT--Cascade Routing Tool to define and visualize flow paths for grid-based watershed models
Watershed scale response to climate change--Sagehen Creek Basin, California
Integrated watershed-scale response to climate change for selected basins across the United States
Decoupled application of the integrated hydrologic model, GSFLOW, to estimate agricultural irrigation in the Santa Rosa Plain, California
Simulation of Runoff and Reservoir Inflow for Use in a Flood-Analysis Model for the Delaware River, Pennsylvania, New Jersey, and New York, 2004-2006
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)
Documentation of the Unsaturated-Zone Flow (UZF1) Package for modeling Unsaturated Flow Between the Land Surface and the Water Table with MODFLOW-2005
Time-dependent Data System (TDDS); an interactive program to assemble, manage, and appraise input data and numerical output of flow/transport simulation models
A computer program for analyzing channel geometry
Science and Products
- Data
- Publications
Filter Total Items: 24
PRMS-IV, the precipitation-runoff modeling system, version 4
Computer models that simulate the hydrologic cycle at a watershed scale facilitate assessment of variability in climate, biota, geology, and human activities on water availability and flow. This report describes an updated version of the Precipitation-Runoff Modeling System. The Precipitation-Runoff Modeling System is a deterministic, distributed-parameter, physical-process-based modeling system dAuthorsSteven L. Markstrom, R. Steve Regan, Lauren E. Hay, Roland J. Viger, Richard M. Webb, Robert A. Payn, Jacob H. LaFontaineSimulation of climate-change effects on streamflow, lake water budgets, and stream temperature using GSFLOW and SNTEMP, Trout Lake Watershed, Wisconsin
Although groundwater and surface water are considered a single resource, historically hydrologic simulations have not accounted for feedback loops between the groundwater system and other hydrologic processes. These feedbacks include timing and rates of evapotranspiration, surface runoff, soil-zone flow, and interactions with the groundwater system. Simulations that iteratively couple the surface-AuthorsRandall J. Hunt, John F. Walker, William R. Selbig, Stephen M. Westenbroek, R. Steve ReganApplication of the Precipitation-Runoff Modeling System (PRMS) in the Apalachicola-Chattahoochee-Flint River Basin in the southeastern United States
A hydrologic model of the Apalachicola–Chattahoochee–Flint River Basin (ACFB) has been developed as part of a U.S. Geological Survey (USGS) National Climate Change and Wildlife Science Center effort to provide integrated science that helps resource managers understand the effect of climate change on a range of ecosystem responses. The hydrologic model was developed as part of the Southeast RegionaAuthorsJacob H. LaFontaine, Lauren E. Hay, Roland J. Viger, Steve L. Markstrom, R. Steve Regan, Caroline M. Elliott, John JonesCRT--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. CRT requires a land-surface elevation for each hydrologicAuthorsWesley R. Henson, Rose L. Medina, C. Justin Mayers, Richard G. Niswonger, R.S. ReganWatershed scale response to climate change--Sagehen Creek Basin, California
General Circulation Model simulations of future climate through 2099 project a wide range of possible scenarios. To determine the sensitivity and potential effect of long-term climate change on the freshwater resources of the United States, the U.S. Geological Survey Global Change study, "An integrated watershed scale response to global change in selected basins across the United States" was startAuthorsSteven L. Markstrom, Lauren E. Hay, R. Steven ReganIntegrated watershed-scale response to climate change for selected basins across the United States
A study by the U.S. Geological Survey (USGS) evaluated the hydrologic response to different projected carbon emission scenarios of the 21st century using a hydrologic simulation model. This study involved five major steps: (1) setup, calibrate and evaluated the Precipitation Runoff Modeling System (PRMS) model in 14 basins across the United States by local USGS personnel; (2) acquire selected simuAuthorsSteven L. Markstrom, Lauren E. Hay, D. Christian Ward-Garrison, John C. Risley, William A. Battaglin, David M. Bjerklie, Katherine J. Chase, Daniel E. Christiansen, Robert W. Dudley, Randall J. Hunt, Kathryn M. Koczot, Mark C. Mastin, R. Steven Regan, Roland J. Viger, Kevin C. Vining, John F. WalkerDecoupled 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 NishikawaSimulation of Runoff and Reservoir Inflow for Use in a Flood-Analysis Model for the Delaware River, Pennsylvania, New Jersey, and New York, 2004-2006
A model was developed to simulate inflow to reservoirs and watershed runoff to streams during three high-flow events between September 2004 and June 2006 for the main-stem subbasin of the Delaware River draining to Trenton, N.J. The model software is a modified version of the U.S. Geological Survey (USGS) Precipitation-Runoff Modeling System (PRMS), a modular, physically based, distributed-parametAuthorsDaniel J. Goode, Edward H. Koerkle, Scott A. Hoffman, R. Steve Regan, Lauren E. Hay, Steven L. MarkstromGSFLOW - 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. BarlowDocumentation 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 ReganTime-dependent Data System (TDDS); an interactive program to assemble, manage, and appraise input data and numerical output of flow/transport simulation models
A system of functional utilities and computer routines, collectively identified as the Time-Dependent Data System CI DDS), has been developed and documented by the U.S. Geological Survey. The TDDS is designed for processing time sequences of discrete, fixed-interval, time-varying geophysical data--in particular, hydrologic data. Such data include various, dependent variables and related parametersAuthorsR.S. Regan, R.W. Schaffranek, R.A. BaltzerA computer program for analyzing channel geometry
The Channel Geometry Analysis Program (CGAP) provides the capability to process, analyze, and format cross-sectional data for input to flow/transport simulation models or other computational programs. CGAP allows for a variety of cross-sectional data input formats through use of variable format specification. The program accepts data from various computer media and provides for modification of macAuthorsR.S. Regan, R.W. Schaffranek - Software