The Ozark Plateaus Groundwater Model: Parameter Effects on Forecast Uncertainty

Monday, December 4, 2017: 1:30 p.m.
101 C (Music City Center)
Leslie Duncan, PhD , Lower Mississippi-Gulf Water Science Center, U.S. Geological Survey, Nashville, TN
Brian Clark , Lower Mississippi-Gulf Water Science Center, U.S. Geological Survey, Fayetteville, AR
Jeremy White , US Geological Survey WRD Texas Water Science Center, Austin, TX

Groundwater models are increasingly used to inform resource-management decisions. As such, it is important to understand how model uncertainty may affect scenario forecasts, particularly if such forecasts could suggest a wide range of possible management outcomes. In 2014, the U.S. Geological Survey (USGS) began developing a regional model of the Ozark Plateaus aquifer system to quantify groundwater availability and to evaluate impacts of climate variability and water-use changes. Water levels in wells screened in the aquifer system respond relatively rapidly to withdrawals and seasonal fluctuations in hydrologic drivers. Some water-level fluctuations exceed 100 ft, creating the need to lower pumps or drill new wells, and drought periods can cause alarm among water managers for municipal and industrial supply and within agricultural communities. Because of the aquifer system’s sensitivity to these fluctuations, the USGS will conduct linear-based, first-order, second-moment (FOSM) uncertainty analysis to estimate forecast uncertainty and to quantitatively evaluate which parameters have the greatest effect on forecast uncertainty. Complementary analysis based on the assumptions of FOSM will be used to estimate the value of additional information to reduce forecast uncertainty. The uncertainty analyses can be enlightening and often identify areas or parameters within the model that could reduce the range in forecast outcomes.
Leslie Duncan, PhD, Lower Mississippi-Gulf Water Science Center, U.S. Geological Survey, Nashville, TN
Dr. Leslie Duncan is a hydrologist with the Lower Mississippi-Gulf Water Science Center in Nashville, Tennessee. She completed her B.S. in mathematics and geosciences at Murray State University, and M.S. and Ph.D. in environmental engineering at Vanderbilt University. Her research interests include groundwater flow modeling and hydroclimatic studies.


Brian Clark, Lower Mississippi-Gulf Water Science Center, U.S. Geological Survey, Fayetteville, AR
Brian Clark is a hydrologist with the USGS. He received a BS from Arkansas Tech (1998) and MS from Baylor University (2000). His research interests include groundwater-flow modeling and geographic information systems.


Jeremy White, US Geological Survey WRD Texas Water Science Center, Austin, TX
Dr. Jeremy White is a hydrologist and groundwater specialist with the Texas Water Science Center in Austin, Texas. He completed his B.S. in computer science at West Texas A&M, and M.S. and Ph.D. in geology at the University of South Florida. Dr. White has extensive experience with parameter estimation and uncertainty quantification in environmental and geophysical models, as well as simulation of surface water and groundwater interactions and density-dependent groundwater flow. Dr. White also has experience using high-performance computing systems to solve massively and embarrassingly parallel problems.


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