Reservoirs in Hydrological Models: Is There a Pilot on Board?
Abstract
Large man-made reservoirs are ubiquitous in river basins worldwide. Their ability to regulate streamflow and store water for a variety of uses makes them both valuable infrastructure and an unavoidable feature of the global hydrological cycle. Yet, representing the operation of these structures, often in the pursuit of several conflicting objectives - e.g., water supply storage and flood control - remains a challenge for hydrological models. This work focuses on demonstrating the shortcomings of two common features of reservoir representation within these models, 1) the absence of coordination between reservoirs, and 2) the validation of reservoir representation exclusively with release-focused goodness-of-fit indicators that span the whole validation period. This is illustrated using the Upper Snake River Basin (USRB) in the Western U.S. as a case-study. Reservoirs in this basin have a total storage capacity that is two-thirds of the long-term average annual discharge at the outlet, denoting a collective ability to considerably regulate streamflow. Among these, several reservoirs on the main stem of the Snake River have the capacity to individually alter streamflow regimes. The USRB is modeled with the Water Balance Model (WBM) from the University of New Hampshire, which comprises an advanced representation of human interferences to the hydrological cycle. Using a sensitivity analysis of daily streamflow and storage outputs to parameters of the release rule in reservoirs, this work demonstrates the importance of 1) understanding the circumstances in which reservoir coordination plays a crucial role in avoiding or mitigating water-related extremes, and 2) accurately representing the response to critical high-flow events at a daily time scale, particularly regarding storage capacity management. These findings have implications regarding the use of hydrological models to assess the expected impacts of water-related hazards in river basins where long-term changes will interact with day-to-day reservoir operations.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFM.H14F..08R
- Keywords:
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- 1880 Water management;
- HYDROLOGYDE: 6319 Institutions;
- POLICY SCIENCESDE: 6344 System operation and management;
- POLICY SCIENCESDE: 6620 Science policy;
- PUBLIC ISSUES