Evaluation of Flow-Resistance Equations for Vegetated Channels and Floodplains

摘要

Riparian vegetation is an integral component of the flood channel because itstabilizes streambanks, provides shade that prevents excessive water temperature fluctuations, supports wildlife, and performs an essential role in nutrient cycling and water quality. Concurrent with the benefits provided by riparian vegetation are the issues pertaining to flood hazard mitigation. Vegetation increases flow resistance, which has a direct effect on the discharge capacity and the level of flood protection provided by the channel. Several methods have been proposed for determining Manning's n in vegetated channels. These methods recognize that the physical characteristics of the vegetation are important factors in evaluating flow resistance. However, minimal research has been conducted to quantify the density and drag characteristics of vegetation. A cooperative study between the U.S. Army Corps of Engineers and Colorado State University was conducted to develop a method of computing flow resistance in vegetated channels and floodplains. A field study was performed in a vegetated channel located near Stillwater, OK as a part of the development of a comprehensive approach to predicting resistance to flow using the Kischenich equation. The channel was characterized for geometry, slope, and vegetation density.