2016 NGWA Groundwater Summit

Downscaling GRACE for groundwater management in California's Central Valley

Tuesday, April 26, 2016: 3:10 p.m.
Platte River Room (The Westin Denver Downtown)
Michelle Miro , University of California, Los Angeles, Los Angeles, CA
James S. Famiglietti , NASA Jet Propulsion Laboratory, Pasadena, CA

Groundwater is a critical component of the local, regional and global water cycle. It constitutes an important storage of water, often relied upon in times of drought and in arid environments. Sustainable planning and management of groundwater resources requires accurate information about trends in groundwater water levels and quantities. In much of the globe, however, this data is limited. The Gravity Recovery and Climate Experiment (GRACE) has already proven to be a powerful data source for regional groundwater assessments in many areas around the world.However, the applicability of this data product to more localized studies and its utility to water management authorities has been constrained by its limited spatial resolution (~150,000 km2). Researchers have begun to address these shortcomings with data assimilation approaches that integrate GRACE total water storage estimates into complex regional models, producing higher-resolution hydrologic results (~4,000 km2). The present study takes these approaches one stepfurther by developing an empirically-based model capable of downscaling GRACE data to a high-resolution (~16 km2) dataset of groundwater storage changes. The model utilizes an artificial neural network (ANN) to generate a series of maps of groundwater level change over the GRACE time period (2002-present) using GRACE estimates of variations in total water storage and a series of publicly available hydrologic variables. The San Joaquin Valley Groundwater Basin in California’s Central Valley serves as the initial case study. Overall, the present study achieves two main goals: 1) it integrates robust numerical methods from the field of systems analysis with geodesy and hydrology; and most importantly 2) it also represents an important application of GRACE data to a local-scale water management study, illustrating how widely available remote sensing data can be utilized by management authorities.

Michelle Miro, University of California, Los Angeles, Los Angeles, CA
Michelle is a PhD candidate in the Department of Civil and Environmental Engineering at UCLA. Her current work utilizes observations from NASA’s GRACE satellite system to develop methods to better estimate local-scale groundwater availability and inform regional water management decisions in California's Central Valley. Overall, she seeks to link water resources policy and planning with interdisciplinary and hydrologic research, particularly for water-stressed and developing regions. Michelle also holds an M.S. in Civil Engineering from the University of Illinois at Urbana-Champaign and is an NSF Graduate Research Fellow and a former U.S. Borlaug Fellow in Global Food Security.

James S. Famiglietti, NASA Jet Propulsion Laboratory, Pasadena, CA
James S. Famiglietti is currently a professor of earth system science at the School of Physical Sciences and a professor of civil environmental engineering at The Henry Samueli School of Engineering, both at the University of California, Irvine. He holds a Ph.D. and an M.A. in civil engineering, an M.S. in hydrology, and a B.S. in geology.