HEC ResSim Water Temperature Independent Peer Review

Background

The U.S. Army Corps of Engineers' (USACE) Hydrologic Engineering Center Reservoir Simulation (HEC ResSim) model is a reservoir system simulation software that allows users to model the behavior and performance of one or more reservoirs under different hydrologic and operational conditions. Users can define the physical characteristics of reservoirs and specify operative policies and objectives to assess reservoir system behavior and manage water storage, releases, and flow through a network of reservoirs. The HEC ResSim model is a valuable tool for water resource managers and engineers to simulate, optimize, and make informed decisions about the operation and management of reservoir systems. Historically, HEC ResSim has not had water temperature modeling capabilities. Water quality capabilities were recently incorporated into HEC ResSim, and part of this capability includes water temperature modeling.

The U.S. Bureau of Reclamation (Reclamation) has undertaken an effort for a Water Temperature Model Platform (WTMP) Project, which entails collecting data, developing a data management system, developing a set of physically based tools, and developing a modeling framework. The WTMP has undergone peer review facilitated by the Delta Science Program. Part of this process highlighted the need for peer review of HEC ResSim as a reservoir temperature modeling tool. A successful application of the WTMP with HEC ResSim would be capable of providing short and long-term water temperature predictions to assist resource managers of reservoir systems.

Reclamation will utilize the reservoir temperature simulation component of HEC ResSim as one component of the WTMP. The development effort covers the northern system—Shasta Lake, Keswick Reservoir, Trinity Lake, Lewiston Reservoir, Upper Trinity River, Upper Sacramento River, Whiskeytown Reservoir, and Clear Creek—the American River system—Folsom Lake, Lake Natoma, and Lower American River—and the Stanislaus River system—New Melones, Tulloch, and Goodwin Reservoirs and Stanislaus Rivers.

The purpose of the Independent Scientific Peer Review is to constructively provide Reclamation with recommendations to improve HEC ResSim as a reservoir temperature simulation model.

Panel Letter Review

The Delta Science Program coordinates reviews in accordance with its mission to provide the best possible unbiased scientific information to inform water and environmental decision-making. As requested by Reclamation, the review will include a Panel Letter developed by the entire panel, which will address the Review Questions in the Charge based on their expertise.

View Reclamation’s request letter to Delta Lead Scientist, Dr. Lisamarie Windham-Myers

View Dr. Windham-Myers's response in PDF format.

Panel Letter Review Materials

Review Documents

Supplemental Material

Charge to the Independent Review Panel

The Charge to the independent review Panel provides the direction, context, and timeline for the review. The Charge includes orientation and focus for the review effort, support materials to be considered, and specific questions for the panel to address during the review process.

View the Charge.

Final Panel Report

  • Read the final Panel Report. Expected May 2025.
  • View the Transmittal Letter from Dr. Lisamarie Windham-Myers, Delta Lead Scientist, to David Mooney, USACE. Expected May 2025.

Review Panel Members

Sarah Null

Associate Professor, Utah State University

Sarah Null is a Professor of Watershed Sciences at the Quinney College of Natural Resources at Utah State University. She received her bachelor's degree in international economics from UCLA and her master’s and PhD in physical geography from UC Davis. Her research focuses on environmental water management and addresses the potential to protect aquatic ecosystems while maintaining water resource benefits for people in water-scarce regions. Current research trajectories focus on 1) improving efficiency and flexibility in environmental water management, 2) monitoring and modeling stream and lake temperatures in the Western US, 3) identifying the portfolio of water infrastructure that is most useful and reliable for 21st Century water management, and 4) environmental water management to preserve saline lakes. She has been awarded a prestigious CAREER award from the National Science Foundation and a STAR award from the US Environmental Protection Agency. Professor Null’s work has been highlighted in diverse media outlets, including The New York Times, Science Magazine, National Geographic, and BBC Newsday. She was the 2021-2022 CalTrout Ecosystem Fellow at the Public Policy Institute of California’s Water Policy Center and is part of a multi-disciplinary team synthesizing cutting-edge research for policy-makers to address lake-level decline in Utah’s Great Salt Lake.

Todd C. Rasmussen (Lead Author)

Professor Emeritus of Hydrology and Water Resources, University of Georgia

Todd Rasmussen is Professor Emeritus of Hydrology & Water Resources in the Warnell School of Forestry and Natural Resources at the University of Georgia, Athens (UGA). He obtained his PhD and MS Degrees in Hydrology from the University of Arizona, Tucson, and his BS Degree from the University of California, Berkeley. His research examines fluid flow, hydrogeochemical fate, and transport in surface and subsurface environments, focusing on the physical, chemical, mathematical, and statistical description and quantification of hydrologic processes. His research includes characterizing the environmental effects of temperature and water-quality changes within and below Southeastern reservoirs. During his over 31-year career at the University of Georgia, Prof Rasmussen directed the UGA Water Faculty and the UGA Water Resources Certificate Programs for both undergraduates and graduates, as well as co-organized the biennial Georgia Water Resources Conference. He has been an Associate Editor for the Journal of Hydrology since 2012.

Laurel Stratton Garvin

Senior Hydrologist, Oregon Water Resources Department

Dr. Stratton Garvin is a Senior Hydrologist at the Oregon Water Resources Department. She is a hydrologist and geomorphologist who studies large, regulated river systems, focusing on stream and reservoir temperature dynamics and modeling, reservoir sedimentation and stratigraphy, and the impact of human management on aquatic habitat. Previously, Dr. Stratton Garvin held positions at USGS and also worked as an environmental consultant primarily focused on environmental characterization and large-scale groundwater contaminant remediation. She holds a master’s degree in hydrogeology from the University of Nevada, Reno, and a Ph.D. in Water Resources Science and Geology from Oregon State University. Dr. Stratton Garvin is a registered geologist in the state of Oregon.

Scott Wells (Panel Chair)

Professor of Civil and Environmental Engineering, Portland State University

Dr. Scott Wells earned his Ph.D. from Cornell University in Civil and Environmental Engineering and graduate and undergraduate degrees from MIT and Tennessee Technological University. Since 1987, he has been at Portland State University and is currently a Professor of Civil and Environmental Engineering after serving for 12 years as Department Chair. His research areas are modeling environmental fluid mechanics, surface water quality and hydrodynamics, and solid-liquid separation processes. Dr. Wells has written over 150 technical publications and is co-developing the water quality and hydrodynamic model CE-QUAL-W2 used worldwide. He has performed water quality and hydrodynamic modeling or performed a peer review of about 200 surface water bodies in the US and abroad.

His research focuses on developing and applying state-of-the-art water quality and hydrodynamic models to rivers, reservoirs, lakes, and estuaries. He and his research team are active as peer reviewers for the US EPA, the State of California, the State Department, and many other organizations. He regularly teaches water quality and hydrodynamic modeling classes at Portland State University, as well as workshops on modeling CE-QUAL-W2. He has presented EPA-sponsored webinars to national and international audiences on the Impact of Sediments on Water Quality and CE-QUAL-W2 and has been invited by EPA Region 6 and the Association of Clean Water Administrators to provide seminars and support workshops on water quality modeling.

He has received two Fulbright scholar awards, one to Ukraine and the other to Israel, where he taught and did research at the Earth Institute at Hebrew University and at the Israeli Geologic Survey in Jerusalem, Israel. In Israel, he worked on the environmental impacts of the proposed Peace Conduit between the Gulf of Aqaba and the Dead Sea. He was also the Science Advisor to a PBS special on saving the Dead Sea.