Abstract: May 29  10:30 AM (BACK)

Stream Restoration in the Arid Southwest: Development of Regional Bankfull Relationships

Allen Haden
Natural Channel Design, Inc.
Flagstaff, AZ

Authors:  Stephanie Yard, P. E., Mark Wirtanen and Tom Moody, P. E. (deceased)
Natural Channel Design, Inc., Flagstaff, AZ

The use of bankfull dimensionless ratios is a fundamental tool for the assessment and design of natural channels.   Assessment, restoration and repair of ecologically and physically functional channels is dependent on reliable prediction of channel dimensions, discharges and sediment loads.  Regional relationships for bankfull dimensions have been developed for many areas of the country.  However, the ephemeral channels of the southwest, characterized by short-lived peak flows provide special challenges.  Research conducted by Natural Channel Design, Inc. has shown that regional relationships of bankfull cross sectional area, depth, width, discharge and sediment load can be developed.   This information has been used successfully for stream channel restoration, aquatic and riparian habitat enhancement and flood damage repair after wildfire over the last decade.  While these practices have proved useful and reliable, there remains a significant challenge to refine these tools through an understanding of sub-regional and watershed condition differences in discharge and sediment loads to meet the rapidly expanding need for channel restoration in the southwest.