Optimizing Spur Dike Orientation for Scour Control in Downward Seepage Scenarios

Abstract

In hydraulic river engineering, river bank protection is crucial to preserving natural rivers, lands, and bridges. As erosion-protective structures, spur dikes protrude outward from the riverbank in different directions to divert the flow away from the bank. The present study examines temporal variation in bed morphology and scours around rectangular-shaped spur dikes with orientations such as 60°, 90°, and 120°. In addition, the formation of maximum scour depth is compared to the condition when downward seepage is applied. The experiments investigated different configurations of spur dike orientation to assess their suitability and the scour progression over time, specifically observing intervals at 2, 12, and 24 hours and comparing them with a 24-hour duration focused on seepage. Findings indicated that a 90º orientation angle produced the most substantial scour depth, while an angle of 120º resulted in the shallowest scour depth. The downward seepage enhanced sediment particle movement, leading to increased particle detachment and deeper scour formations. Scour depth initially starts at the tip of the spur dike and reaches its maximum there. Sand particles were deposited downstream, creating a dune-like structure near the second spur dike. Keywords: Temporal scour variation, Bed morphology, Oriented spur dikes, Downward seepage.