Author(s): John O. Goreham; S. Kyle Mckay; Mark C. Stone; Kumud Acharya; J. Craig Fischenich
Linked Author(s): Mark Stone
Keywords: No Keywords
Abstract: Encroachment of vegetation is a severe water resources management problem in canals, streams, and rivers in the American West. Hydraulic engineers have traditionally viewed vegetation as part of a maintenance program and hence, have not accounted for long-term impacts if left unchecked. As a result of increasing recognition of ecological benefits, existing flood reduction systems must often be reanalyzed to allow for vegetation as a source of habitat for various aquatic and riparian species. The allowance of aquatic and riparian vegetation in older projects results in increased roughness which affects hydraulic conveyance. The end effect is an increase in hydraulic roughness (and water surface elevation) for a given flow event. It is known that a portion of the vegetation may be washed out during high flow events, which could potentially increase conveyance – and possibly induce a debris hazard downstream; however, both the bending and amount of washout for a given discharge and plant community is not well studied. The objective of this study is to develop predictive relationships for the bending and washout of select woody vegetation species in the Southwestern United States. This was accomplished through a series of field tests to quantify bending, uprooting and breaking conditions under an applied force. The results will be helpful for supporting bioengineering installation, management of invasive species through washout, and investigation of riparian forest stability in large wind events.
Year: 2009