A Diagnostic Framework and Data Inventory to Analyze Human Intervention on Streamflow

Human activities—such as reservoir operations, canal diversions, and water withdrawals for irrigation, municipal, industrial, and power-plant uses—can substantially alter streamflow regimes. Accurately predicting these impacts requires their explicit inclusion in hydrological models, yet data scarcity has historically hindered realistic representation. This situation has improved as data describing water management activities have become increasingly available.

This talk will demonstrate the extent to which state-of-the-art data on human interventions can improve streamflow simulations in large-scale hydrological models (LSHMs), thereby reducing the oversimplified assumptions about human activities found in existing models. The analysis is conducted using a diagnostic framework based on a comprehensive database of U.S. water management interventions to identify which activities most strongly modify streamflow and where. Applying this framework to the Mississippi River Basin reveals that streamflow predictions improve only when both reservoir management and irrigation—the two activities exerting the greatest influence on flow regimes in the Missouri and Arkansas–White–Red regions—are explicitly represented. Our analysis also identifies critical data gaps in canal-diversion records along the Platte River, the representation of artificial tile drainage in the Ohio region, and surface water–groundwater interaction data for the Arkansas–White–Red region. This talk concludes with a discussion of future research directions, especially a systems-based approach to capturing the interactions among multiple, concurrent human interventions in hydrologic systems.

About the Presenter

Ximing Cai is Professor of Civil and Environmental Engineering at the University of Illinois Urbana-Champaign. His primary research area is water resources systems analysis, with a focus on coupled hydrology-human systems. His work emphasizes interdisciplinary research by integrating hydrology and economics to better understand the complexity of environmental and water resources systems, thereby providing critical decision support for water resources management. He has been elected as a fellow of the American Geophysical Union (AGU) and the International Water Resources Association (IWRA). He is the recipient of the 2023 Julien Hinds Award of American Society of Civil Engineers and 2024 Warren Hall Medal from the University Council of Water Resources (UCOWR), both of which recognize his contributions to interdisciplinary research in water resources. He currently serves as the Chair of the IWRA Task Force Committee on Downscaling SDGs to water management decision-making scales.

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