"Integrated Hydrologic Model Development and Evaluation (for Non-Modelers)"

Presented By:

Douglas Tolley, Ph.D.

 INTRODUCTION:

Numerical models are often used in hydrology to represent the complex, physical flow processes that occur in natural systems. Although simplified representations of reality, numerical models can be quite complex. This is especially true for integrated hydrologic models, which try to represent different processes and how they affect other parts of the system (e.g., crop-water demand and groundwater pumping; groundwater-surface-water interactions; climate change and ET; etc.). The complexity of integrated models can make them difficult for non-modelers to evaluate, especially since terms like “sensitivity,” “calibration,” and “uncertainty” that come with complex equations are often used when they are presented. We define these and other general modeling terms and their methods for a broad audience using the Scott Valley Integrated Hydrologic Model (SVIHM) as an example. This talk will demonstrate how disagreement between simulated results and observations can inform the conceptual model of the system, that hydrologic models that do not simulate crop-water demand are missing parameters that strongly influence calibration results, and that weakly coupled integrated models are a viable, computationally efficient approach to properly reproduce observed groundwater-surface-water interactions.

SPEAKER BIOS:

Douglas Tolley, Ph.D. received a B.S. in geology from UC Santa Barbara, a M.S. in hydrology from New Mexico Institute of Mining and Technology, and a Ph.D. in hydrology from UC Davis. His doctoral research focused on groundwater-surface-water interactions in agricultural groundwater basins with groundwater dependent ecosystems. He has experience with development, sensitivity analysis, calibration, and uncertainty analysis of integrated hydrologic models. He was one of the lead developers of the Scott Valley Integrated Hydrologic Model (SVIHM), which is currently being used to formulate the groundwater sustainability plan for the basin. He recently returned to Daniel B. Stephens & Associates where he is working out of the Grass Valley, CA office.

MODERATOR BIO:

Thomas Harter, Ph.D. is a Cooperative Extension faculty and the Robert M. Hagan Endowed Chair in Water Management and Policy at the Department of Land, Air, and Water Resources; University of California, Davis.  With more than 20 years of research, outreach, and teaching experience, his interests focus on nonpoint-source pollution of groundwater, sustainable groundwater management, groundwater modeling, groundwater resources evaluation under uncertainty, groundwater-surface water interaction, and on contaminant transport. Dr. Harter's research group has done extensive modeling, laboratory, and field work to evaluate the impacts of agriculture and human activity on groundwater flow and contaminant transport in complex aquifer and soil systems. Dr. Harter is frequently speaking to public, technical, and scientific audiences, and is an active advisor for local, state, and federal organizations.

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Contact Sarah at serck@grac.org