Research and Development Office

Linking Extreme Precipitation and Floods: Implications for Climate Change Scenarios

Project ID: 879
Principal Investigator: Jeanne Godaire
Research Topic: Managing Hydrologic Events
Priority Area Assignments: 2012 (Climate Change and Variability Research)
Funded Fiscal Years: 2012
Keywords: basin response, floods, extreme precipitation

Research Question

In the recent report produced by the U.S. Army Corps of Engineers (Corps) and the Bureau of Reclamation (Reclamation) (2011) titled "Addressing Climate Change in Long-term Water Resources Planning and Management," Assessing Natural System Responses (Technical Step 4) was identified as a data gap and high priority area for longer-term climate change research. This proposal intends to address basin response to hydrologic events under data gap 4.03, Method and basis for estimating extreme hydrologic event possibilities, deterministically or probabilistically, in a changing climate.

This study proposes to investigate the runoff response of watersheds to extreme precipitation (rainfall) recorded in basins of the western U.S. and to understand the basin and storm conditions that produce the largest floods. Simply stated, this study seeks to answer the question, "Do the largest precipitation events produce the largest floods and, if not, why?" While this question may seem relatively simple, there are many factors that can complicate the relationship between rainfall and floods.

While rainfall runoff models are a useful predictive tool, they require intensive inputs to accurately portray complex topography, soils, geology, antecedant moisture, and resultant runoff from storms that impact basins of the intermountain west. Historical data can be used in many basins to first understand how precipitation and runoff are related under recent historical conditions and then to apply this understanding to how basins might respond in the future given changes in climate.

Need and Benefit

Changes in streamflow magnitude, frequency, and volume will undoubtedly impact Reclamation structures from both a dam safety and water operations perspective. Understanding the potential basin response given various climate change scenarios will be important in long-term planning for water resource managers. In many basins of the western U.S., floods are the largest contributors to reservoir levels or volumes and determine much of the operations of the dam based on their predicted magnitudes and volumes during a given water year. Understanding how these events will change for particular basins where Reclamation structures exist will be very beneficial for dam operations and dam safety. These predictions should aid in operating the reservoir in the most efficient manner in terms of water conservation. It should also assist in dam safety risk assessments by providing new data concerning input parameters for rainfall runoff models in areas where rainfall-runoff relationships are predicted to change considerably.

Reclamation will also benefit from this project by continued involvement with other agencies and researchers in the emerging science regarding climate change and floods. Interaction with other researchers on climate simulations and rainfall-runoff modeling is anticipated as well as with other agencies as part of the Extreme Events Hydrology Group that was convened by Reclamation and included staff from National Oceanic and Atmospheric Administration (NOAA), U.S. Geological Survey (USGS), and Reclamation. If the research produces viable results, the author plans to publish the material in a peer-reviewed journal.

Contributing Partners

Contact the Principal Investigator for information about partners.

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.

Linking Extreme Precipitation and Floods: Implications for Climate Change Scenarios (final, PDF, 983KB)
By Jeanne Godaire
Research Product completed on October 01, 2012

Linking Extreme Precipitation and Floods: Implications for Climate Change Scenarios (final, PDF, 2.3MB)
By Jeanne Godaire
Research Product completed on October 02, 2012

---

Return to Research Projects