Channel-Forming Discharge
Abstract
PURPOSE: The purpose of this Technical Note is to provide guidance and cautions to be used in approximating channel-forming discharge with bankfull, specified recurrence interval, and effective discharge methodologies. There are limitations for each of these three methods that the user must recognize. INTRODUCTION: An alluvial river adjusts the dimensions of its channel to the wide range of flows that mobilize its boundary sediments. For many rivers and streams, it has been observed that a single representative discharge may be used to determine a stable channel geometry. The use of a single representative discharge is the foundation of regime and hydraulic geometry theories for determining morphological characteristics of alluvial channels. This representative channel-forming (dominant) discharge has been given several names by different researchers, including bankfull, specified recurrence interval, and effective discharge. This has led to confusion with both terminology and understanding of fundamental stream processes. In this Technical Note the channel-forming (dominant) discharge is defined as a theoretical discharge that if maintained indefinitely would produce the same channel geometry as the natural long-term hydrograph. Channel-forming discharge concepts are applicable to stable alluvial streams (i.e., streams that have the ability to change their shape and are neither aggrading nor degrading). For channels in arid environments where runoff is generated by localized highintensity storms and the absence of vegetation ensures that the channel will adjust to each major flood event, the channel-forming discharge concept is generally not applicable.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 2000
- Accession Number
- ADA604706
Entities
People
- D. S. Biedenharn
- J. Craig Fischenich
- R. R. Copeland
Organizations
- Engineer Research and Development Center