Impacts from Operational Releases to Populations at Risk

Project ID: 1227
Principal Investigator: Anastasia Johnson
Research Topic: Public and Employee Safety
Funded Fiscal Years: 2014
Keywords: operational releases, flood stage, safe channel capacity, emergency management,

Research Question

Which Reclamation dams have the potential to pass operational flood releases (non-failure) that exceed the safe channel capacity or National Weather Service recognized flood stage below the dam?
What inundation mapping is available for each facility where there is the potential for operational releases that exceed the safe channel capacity or flood stage below the dam, and how does available mapping correlate with maximum operational releases?
What is the approximate population at risk during high operational releases without dam failure?
Is there potential life loss associated with operational releases?

Need and Benefit

The flood plains downstream of many Reclamation dams have become increasingly populated over time. As a result of community growth and encroachment into these flood plains, Reclamation dams now pose a greater threat of adverse consequences to populations downstream than original designers, planners and developers envisioned for our projects.

A significant challenge for the emergency preparedness program is to adequately prepare dam owners and operators not only for dam failure, but also to effectively manage large operational or uncontrolled releases in a safe manner in order to minimize the threat to life and economic consequences. The planned nature of operational releases allows a unique opportunity for coordination with downstream communities to enable organized responses to those releases should they occur.

Determining the specific structures for which there is the potential for release of life threatening flows, and the degree of inundation expected due to those flows, is an important step in developing a holistic, all-hazards emergency preparedness strategy for all Reclamation dams and their downstream communities.

Contributing Partners

None

Research Products

Bureau of Reclamation Review

The following documents were reviewed by experts in fields relating to this project's study and findings. The results were determined to be achieved using valid means.

Impacts from Operational Releases to Populations at Risk (final, PDF, 149KB)
By Stacy Johnson
Publication completed on September 30, 2015

With the initial intent of estimating impacts (risk-based) to downstream populations during operational release events, data was assembled and analyzed from a variety of sources. These data sets were then the basis of discussion regarding the usefulness of such information, and the value to be gained by trying to assemble more accurate data. It was determined that refinement of the data set would take a significant amount of money and time, and the benefits would not be comparable to the expense. Rather, the most effective method to deal with operational releases and subsequent risks to the population is to continue utilizing the emergency exercise process, which has seen a great deal of improvement in the last several decades.
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Last Updated: June 29, 2015