Andrew J Long
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.
Biography
Selected Appointments:
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 involving numerical modeling.
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
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...
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...
Walla Walla Groundwater
The Issue: Within the states of Washington and Oregon, the 1,777 mi2 Walla Walla River Basin (WWRB) is a complex hydrogeologic system with long-term water-level declines in regional aquifers and insufficient instream flows required for threatened and culturally important fish populations. The public and state resource management agencies need an improved...
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...
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....
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: 2007-2010
Cooperator: National Park Service
Project Chief: Andrew Long
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...
Spectral analysis to quantify the response of groundwater levels to precipitation—Northwestern United States
Persistent atmospheric patterns that lead to wet and dry seasons and droughts over periods of months to decades and longer-term climate change over periods of decades to millennia affect groundwater resources. Changes in groundwater storage and the resulting groundwater discharge from most aquifers is relatively slow and steady compared to the...
Long, Andrew J.; Konrad, Christopher P.
300,000 yr history of water-table fluctuations at Wind Cave, South Dakota, USA—Scale, timing, and groundwater mixing in the Madison Aquifer
Deposits of calcite coating the lower passages of Wind Cave in the southern Black Hills of South Dakota were precipitated under phreatic conditions. Data from samples associated with a new cave survey and hydrologic studies indicate that past water tables within Wind Cave reached a maximum height of 45 m above modern levels but were mostly...
Paces, James; Palmer, Margaret V.; Palmer, Arthur N.; Long, Andrew J.; Emmons, Matthew P. Multivariate analysis of hydrochemical data for Jewel Cave, Wind Cave, and surrounding areas
Jewel Cave National Monument and Wind Cave National Park in South Dakota contain two of the six longest caves worldwide. These caves contain subterranean lakes that are important points of intersection between the water table of the Madison aquifer and the caves. During 2015 to 2017, several subterranean lakes were discovered in Jewel Cave, which...
Long, Andrew J.; Paces, James B.; Eldridge, William G.
Data management plan for the U.S. Geological Survey Washington Water Science Center
The primary mission of the U.S. Geological Survey (USGS) Water Mission Area is to collect and disseminate reliable, impartial, and timely information needed to understand the water resources of the Nation, including data on streamflow, groundwater, water quality, water use, and availability. Management of data throughout the entire data lifecycle...
Conn, Kathleen E.; Mastin, Mark C.; Long, Andrew J.; Dinicola, Richard S.; Barton, Cynthia
Williston Basin groundwater availability, United States and Canada
The Williston Basin contains important oil and gas resources for the Nation. Freshwater supplies are limited in this semiarid area, and oil and gas development can require large volumes of freshwater. Groundwater is the primary source of water for many water users in the Williston Basin, so to better understand these resources, the U.S. Geological...
Thamke, Joanna N.; Long, Andrew J.; Davis, Kyle W.
Groundwater availability of the Williston Basin, United States and Canada
Executive SummaryThe Williston Basin of the Northern Great Plains is a sedimentary basin—a geologic bowl-like structure filled with layered sedimentary rocks dating as far back as the Paleozoic age. The basin, which is nationally important for the production of energy resources, spans Montana, North Dakota, and South Dakota in the United States,...
Long, Andrew J.; Thamke, Joanna N.; Davis, Kyle W.; Bartos, Timothy T.
Construction and calibration of a groundwater-flow model to assess groundwater availability in the uppermost principal aquifer systems of the Williston Basin, United States and Canada
The U.S. Geological Survey developed a groundwater-flow model for the uppermost principal aquifer systems in the Williston Basin in parts of Montana, North Dakota, and South Dakota in the United States and parts of Manitoba and Saskatchewan in Canada as part of a detailed assessment of the groundwater availability in the area. The assessment was...
Davis, Kyle W.; Long, Andrew J. Potential application of radiogenic isotopes and geophysical methods to understand the hydrothermal dystem of the Upper Geyser Basin, Yellowstone National Park
Numerous geochemical and geophysical studies have been conducted at Yellowstone National Park to better understand the hydrogeologic processes supporting the thermal features of the Park. This report provides the first 87Sr/86Sr and 234U/238U data for thermal water from the Upper Geyser Basin (UGB) intended to evaluate whether heavy radiogenic...
Paces, James B.; Long, Andrew J.; Koth, Karl R. RRAWFLOW: Rainfall-Response Aquifer and Watershed Flow Model (v1.15)
The Rainfall-Response Aquifer and Watershed Flow Model (RRAWFLOW) is a lumped-parameter model that simulates streamflow, spring flow, groundwater level, or solute transport for a measurement point in response to a system input of precipitation, recharge, or solute injection. I introduce the first version of RRAWFLOW available for download and...
Long, Andrew J.
Effects of projected climate (2011–50) on karst hydrology and species vulnerability—Edwards aquifer, south-central Texas, and Madison aquifer, western South Dakota
Karst aquifers—formed by the dissolution of soluble rocks such as limestone—are critical groundwater resources in North America, and karst springs, caves, and streams provide habitat for unique flora and fauna. Springflow and groundwater levels in karst terrane can change greatly over short time scales, and therefore are likely to...
Mahler, Barbara; Stamm, John F.; Poteet, Mary F.; Symstad, Amy J.; Musgrove, MaryLynn; Long, Andrew J.; Norton, Parker A.
Historical and projected climate (1901–2050) and hydrologic response of karst aquifers, and species vulnerability in south-central Texas and western South Dakota
Two karst aquifers, the Edwards aquifer in the Balcones Escarpment region of south-central Texas and the Madison aquifer in the Black Hills of western South Dakota, were evaluated for hydrologic response to projected climate change through 2050. Edwards aquifer sites include Barton Springs, the Bexar County Index Well, and Comal Springs. Madison...
Stamm, John F.; Poteet, Mary F.; Symstad, Amy J.; Musgrove, MaryLynn; Long, Andrew J.; Mahler, Barbara; Norton, Parker A.
Conceptual model of the uppermost principal aquifer systems in the Williston and Powder River structural basins, United States and Canada
The three uppermost principal aquifer systems of the Northern Great Plains—the glacial, lower Tertiary, and Upper Cretaceous aquifer systems—are described in this report and provide water for irrigation, mining, public and domestic supply, livestock, and industrial uses. These aquifer systems primarily are present in two nationally important...
Long, Andrew J.; Aurand, Katherine R.; Bednar, Jennifer M.; Davis, Kyle W.; McKaskey, Jonathan D.R.G.; Thamke, Joanna N.