الگوي رسوبگذاري و فرسايش در دماغه آبشكن هاي واقع در سيلاب دشت رودخانه

Erosion and Sedimentation Pattern at the Spur Dikes Endings on the Floodplains

Soil erosion and its associated impacts, is one of the most important of todayʹs environmental problems because, agricultural land is seriously degraded. Erosion is the removal of solids in the natural environment. Water is the most important erosion agent and erodes most commonly as running water in streams and rivers. Also when flow speed in rivers is halted, the river deposits its sediments and may cause some problems. In rivers with flood plain, the erosion happens when the flow contact strongly to bank of river. To prevent these, spur dikes have been widely used to protect eroding stream banks and causing sedimentation to change the flow direction away from river banks to the river center. However, much is yet to be researched about the influence and effects of spur dikes during large amount of flow (floods). For these reasons some experimental tests are designed to predict the behavior and influence of length and shape of spur dikes. In this paper the result of scour at spur dikes ending, which are installed in floodplain in a series as single side of flood plain with the length of 10 and 20 centimeters of spur dikes. The scour and sedimentation pattern and also maximum scouring at the end of spur dikes are measured and the experimental results are analyzed and discussed.