Document Type : Research Paper
Authors
1 Assistant Professor, Department of Irrigation, Ahvaz Unit, Azad Islamic University, Iran
2 Associate Professor, Faculty of Water Science Engineering, Shahid Chamran University, Ahvaz, Iran
Abstract
The existence of vegetation cover in a region can reduce the velocity of surface run-off and prevent soil erosion. This can substantially control the occurrence of destructive floods in the region. One reliable method used in protecting flood-forming catchments is the biological method. Also, one factor that represents the hydraulic resistance in plants is roughness coefficient. Measuring the coefficient and its impact on the flow velocity and shear stress reduction in the plants is of outmost importance. One of the known species used extensively in soil stabilization and protection is Tamarix sricta .This species resists against various climates and is easy to be planted. With its needle leaves and rough external organs, Tamarix sricta reduces the flow velocity and prevents further soil erosion. In this research roughness coefficient of the Tamarix sricta was investigated. The plant studied in non-submerged and sub critical condition flow using a flume with the length of 12.6 m, width of 0.5 m and height of 0.6 m in different velocity, discharge and depths. The height of plants in this is 35 cm with a natural arrangement in trays of 2.8 m in length laid over the bed of the flume. The total number of the experiments is 22.The results of this study show that roughness coefficient of plants is function of velocity, depth, hydraulic radius and plant types. Because of its high roughness, this species is an appropriate alternative to be used in reducing the flow velocity and protecting the soil from any erosion possibility.
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