Effective Discharge in Alluvial Channels

Principal Investigator: Dr. Andrew Simon

Problem:

The effective discharge is a geomorphic concept representing that flow, or range of flows that transport the most sediment over the long term. The effective discharge has been equated with the bankfull discharge and both have been used more frequently in recent years in stream-restoration strategies.

Objective:

Research is aimed at determining if the recurrence interval of the effective discharge across the United States.

Description of Work:

Historical flow and suspended-sediment transport data will be used to develop rating relations for about 3,000 sites. Flow frequency and peak-flow analysis will be used to develop the peak-flow series and recurrence intervals for all sites. Multiplying the sediment load at a given flow-class by the frequency of occurrence for each of 33 classes will provide long-term tansport estimates for each class. The class with the highest load is the effective discharge

Benefit:

Results will provide a means of comparing watershed of different size and from different regions and can potentially have a large impact on the development of new "regime" equations for prediction of stable channel geometries, which are currently based on the 1.0 to 2.33-year recurrence interval.