Effect of erect grasses on inflow hydraulics and sediment retention within a creeping grass strip

in International Symposium (oral presentation paper), 國際研討會(全文口頭發表)
標題Effect of erect grasses on inflow hydraulics and sediment retention within a creeping grass strip
AuthorsWu, 吳嘉俊, Chi-Han Chiang 蔣季翰, Yi-Sin Jiang 江宜欣, Zih-Siang Lin 林子祥, & Siao-Wun Chu?筱雯
出版日期Sep 4 2008 12:0
會議地點Oxford, Mississippi

Grass strip, part of an ideal vegetative buffer strip, usually plays an important role in sediment and pollutant removal. There have been numerous studies conducted that focused on different aspects of vegetation buffer strips. The main objective of this study is to experimentally investigate how single- and double rows of erect grasses affect sediment retention and hydraulic conditions within a grass strip.
Experimental parameters related to this study included slope gradient, mean sediment size, inflow rate, and combinations of single- and double-row of erect grass. Guinea grass, considered as erect was installed at the front end of a 4.5-m wide Bahia grass which was considered as creeping grass in this study. Flow velocities, elevations of flow surfaces and sediment deposition within the Bahia grass strip, as well as sediment load leaving the grass strip were sampled during the experiments.
Results of this study indicate that as slope gradient increased to 20%, gaps between erect grass stems cause inflow to concentrate that apparently increase flow velocity, reduce sediment retention, change hydraulic conditions, allow sediment to advance farther in grass strip, and shorten the sediment runout time. Double-hedge row appears to perform even worse on steeper slopes by encouraging the formation of steep hydraulic gradient immediately downstream of the hedge.

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