Andy Long has more than 25 years of experience assessing groundwater flow and transport through numerical modeling, analyzing ambient and injected tracers, and geophysical methods.
Professional Experience
Groundwater Specialist, USGS Washington Water Science Center (July 2015 – present) - I advise and train staff scientists and technicians on technical issues, including interpretive studies and the collection, management, and archival of data. I advise managers of the science center in building and guiding the overall groundwater studies and data programs. I conduct scientific investigations involv
Chair and Vice Chair, Washington Hydrogeology Symposium (2017 – present) – http://depts.washington.edu/uwconf/wordpress/wahgs/
Research Hydrologist, USGS Dakota Water Science Center (DWSC; 2009 – 2015) –
Developed innovative methods to better understand, quantify, and test hypotheses related to groundwater flow and transport in karst aquifers. Topics include groundwater age dating, lumped-parameter models, aquifer classification, hydrochemical evaluation, heat transport, and groundwater recharge.
Adjunct Assistant Professor, South Dakota School of Mines and Technology (SDSMT; Oct 2005 – 2018) –
Served on eight graduate advisory committees for M.S. and Ph.D. students and gave numerous guest lectures.
Hydrologist, USGS DWSC (Jan 1999 – Oct 2009) –
This involved numerical modeling of groundwater flow and solute transport, dye tracing experiments in karst aquifers, aquifer pumping tests, and development of new research models.
Consultant (1994–1998) –
Conducted GIS analysis and groundwater modeling with MODFLOW related to a proposed low-level nuclear-waste site for the Boyd County Monitoring Committee in Nebraska. Consulted for Terra Nitrogen in Sergeant Bluff, Iowa and simulated groundwater flow and transport with MODFLOW, MOC, and GIS analysis to assess the movement of ammonia contamination.
Research assistant, SDSMT (1995–1998) –
Developed and wrote the FORTRAN computer code for a three-dimensional groundwater model to simulate dual-porosity flow in karst aquifers. Collaborated with a team of researchers on the design of a numerical model to simulate surface-water and groundwater flow, dynamically linked to atmospheric processes.
Hydrologist, Rapid City Water Department (1994-1995) –
Collaborated with the USGS to simulated groundwater flow in karst aquifers.
Science and Products
Filter Total Items: 13
Hydrochemical Analysis of Groundwater in Jewel Cave National Monument
The Issue: The park’s landscape and geomorphology is characterized as a carbonate karst environment, with sinking streams and fast connections between surface water and groundwater, resulting in high vulnerability of contamination to groundwater. Now that subterranean lakes have been discovered in Jewel Cave, understanding the groundwater connection of the lakes therein to the lakes in nearby Wind...
Assess the utility of a regional aquifer system groundwater model to inform the USGS National Hydrologic Model
The Issue: In Washington State, groundwater (GW) inflow to streams, or baseflow, is essential for maintaining aquatic habitats, and for out-of-stream uses such as irrigated agriculture during the typically dry summers. However, the National Hydrologic Model (NHM) currently is most suited to predicting total daily streamflow. This project aims to assess the NHM’s performance in simulating baseflow...
Walla Walla River Basin groundwater-flow system, Oregon-Washington
The Issue: Decades of declining groundwater levels in the Walla Walla River Basin (WWRB), which spans Oregon and Washington, are affecting instream flows for threatened and culturally important fish populations and water availability for competing interests across state lines. The public and state resource management agencies have begun implementing efforts to stabilize groundwater levels and...
Williston and Powder River Basins Groundwater Availability Study
The development of two nationally important energy-producing areas, the Williston structural basin (containing the Bakken Formation) and Powder River structural basin, provide a critical opportunity to study the water-energy nexus within a groundwater context. Large volumes of water are needed for energy development in these basins. The hydraulically connected aquifers in the regional glacial...
Keyport Groundwater Model
The Issue: Chlorinated volatile organic compounds have impacted groundwater beneath a former 9-acre landfill at OU 1 of the Naval Base Kitsap Keyport, Washington. The landfill is adjacent to tidal flats that are an extension of Liberty and Dogfish Bays and was the primary disposal area for domestic and industrial waste generated by NBK Keyport from the 1930s through 1973. The Navy needs a detailed...
Quincy Groundwater
The Issue: Since 1952, water diverted from the Columbia River for irrigation in parts of the Quincy Subarea in eastern Washington has resulted in rising groundwater levels and increased groundwater flows and storage. Managers of groundwater in the area need a better understanding of the flow system before and after the start of irrigation. How the USGS will help: In a joint effort with Washington...
RRAWFLOW: Rainfall-Response Aquifer and Watershed Flow Model
RRAWFLOW: Rainfall-Response Aquifer and Watershed Flow Model
Groundwater Flow, Quality, and Mixing in the Wind Cave National Park Area, South Dakota
Project Period: 2007-2010Cooperator: National Park ServiceProject Chief: Andrew Long
Kitsap Groundwater Model
The Issue: Groundwater provides a major source of drinking water for the population of the Kitsap Peninsula. Consequently, as the population grows, so does the demand for groundwater. However, the quantity of usable groundwater is limited, largely because the Peninsula is bounded by seawater and the potential for water-level declines and seawater intrusion increases as groundwater usage increases...
Pasco Groundwater Storage
The Issue: Since 1952 water diverted from the Columbia River has been used to irrigate parts of the Pasco basin in eastern Washington. As a result of the surface-water irrigation, groundwater levels generally have risen in the area. The increases in groundwater fluxes and groundwater in storage have created a need to better understand the flow system before and after the start of irrigation to...
Chimacum GW Model
Projected increases in population and development in northeastern Jefferson County, Washington, are expected to lead to increased groundwater withdrawals in the Chimacum Creek Basin. Changes in land use and climate could reduce groundwater recharge, thereby reducing groundwater available for drinking and for baseflow to streams that host endangered fish species. The USGS is developing quantitative...
Yakima River Basin
The Yakima River flows 215 miles from the outlet of Keechelus Lake in the central Washington Cascades southeasterly to the Columbia River, draining an area of 6,155 square miles. The Yakima River Basin is one of the most intensively irrigated areas in the United States. Population in the Yakima River Basin was about 238,000 in 1990. Increasing demands for water for municipal, fisheries...
Science and Products
- Science
Filter Total Items: 13
Hydrochemical Analysis of Groundwater in Jewel Cave National Monument
The Issue: The park’s landscape and geomorphology is characterized as a carbonate karst environment, with sinking streams and fast connections between surface water and groundwater, resulting in high vulnerability of contamination to groundwater. Now that subterranean lakes have been discovered in Jewel Cave, understanding the groundwater connection of the lakes therein to the lakes in nearby Wind...Assess the utility of a regional aquifer system groundwater model to inform the USGS National Hydrologic Model
The Issue: In Washington State, groundwater (GW) inflow to streams, or baseflow, is essential for maintaining aquatic habitats, and for out-of-stream uses such as irrigated agriculture during the typically dry summers. However, the National Hydrologic Model (NHM) currently is most suited to predicting total daily streamflow. This project aims to assess the NHM’s performance in simulating baseflow...Walla Walla River Basin groundwater-flow system, Oregon-Washington
The Issue: Decades of declining groundwater levels in the Walla Walla River Basin (WWRB), which spans Oregon and Washington, are affecting instream flows for threatened and culturally important fish populations and water availability for competing interests across state lines. The public and state resource management agencies have begun implementing efforts to stabilize groundwater levels and...Williston and Powder River Basins Groundwater Availability Study
The development of two nationally important energy-producing areas, the Williston structural basin (containing the Bakken Formation) and Powder River structural basin, provide a critical opportunity to study the water-energy nexus within a groundwater context. Large volumes of water are needed for energy development in these basins. The hydraulically connected aquifers in the regional glacial...Keyport Groundwater Model
The Issue: Chlorinated volatile organic compounds have impacted groundwater beneath a former 9-acre landfill at OU 1 of the Naval Base Kitsap Keyport, Washington. The landfill is adjacent to tidal flats that are an extension of Liberty and Dogfish Bays and was the primary disposal area for domestic and industrial waste generated by NBK Keyport from the 1930s through 1973. The Navy needs a detailed...Quincy Groundwater
The Issue: Since 1952, water diverted from the Columbia River for irrigation in parts of the Quincy Subarea in eastern Washington has resulted in rising groundwater levels and increased groundwater flows and storage. Managers of groundwater in the area need a better understanding of the flow system before and after the start of irrigation. How the USGS will help: In a joint effort with Washington...RRAWFLOW: Rainfall-Response Aquifer and Watershed Flow Model
RRAWFLOW: Rainfall-Response Aquifer and Watershed Flow ModelGroundwater Flow, Quality, and Mixing in the Wind Cave National Park Area, South Dakota
Project Period: 2007-2010Cooperator: National Park ServiceProject Chief: Andrew LongKitsap Groundwater Model
The Issue: Groundwater provides a major source of drinking water for the population of the Kitsap Peninsula. Consequently, as the population grows, so does the demand for groundwater. However, the quantity of usable groundwater is limited, largely because the Peninsula is bounded by seawater and the potential for water-level declines and seawater intrusion increases as groundwater usage increases...Pasco Groundwater Storage
The Issue: Since 1952 water diverted from the Columbia River has been used to irrigate parts of the Pasco basin in eastern Washington. As a result of the surface-water irrigation, groundwater levels generally have risen in the area. The increases in groundwater fluxes and groundwater in storage have created a need to better understand the flow system before and after the start of irrigation to...Chimacum GW Model
Projected increases in population and development in northeastern Jefferson County, Washington, are expected to lead to increased groundwater withdrawals in the Chimacum Creek Basin. Changes in land use and climate could reduce groundwater recharge, thereby reducing groundwater available for drinking and for baseflow to streams that host endangered fish species. The USGS is developing quantitative...Yakima River Basin
The Yakima River flows 215 miles from the outlet of Keechelus Lake in the central Washington Cascades southeasterly to the Columbia River, draining an area of 6,155 square miles. The Yakima River Basin is one of the most intensively irrigated areas in the United States. Population in the Yakima River Basin was about 238,000 in 1990. Increasing demands for water for municipal, fisheries... - Data
- Publications