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Duckbill weir is one of the water level control structures in irrigation networks, which is of interest to many engineers. Sediments transported in irrigation networks accumulate upstream of duckbill weirs, cause problems in operation, and affect the upstream water level. In this paper, submerged vanes and bottom slots are investigated for flushing the sediment downstream of the said weir. The experiments were conducted in a rectangular flume, 12 m long, and 0.6 m wide. The vanes placed in four sections were perpendicular to the sidewall. The Flow-3D software was used for simulation of flow and sedimentation patterns. The results showed that submerged vanes create a secondary flow which is very useful for flushing the sediment especially in the value of H/p ≥ 0.33 (H is head over the sidewall and p is the weir height). Further, the results showed duckbill weir efficiency (which is defined as the ratio of sediment trap to flow capacity of the weir) is as high as 47% (for values of H/p = 0.1–0.5 and total models). Finally, image processing results showed a maximum relative error of 14.4% for the simulation of sediment pattern with Flow-3D software.

Scour is a natural phenomenon that is created by the rivers streams or the flood which brings about transferring or eroding of bed materials. To have accurate and safe erosion control structures design, maximum scour depth in downstream of the structures gains specific significance. In the current study, M5 model tree as remedy data mining approaches is suggested to estimate the scour depth around the abutments. To do this, Kayaturk laboratory data (2005), with different hydraulic conditions, are used. Then, the results of M5 model were also compared with genetic programming (GP) and pervious empirical results to investigate the applicability, ability, and accuracy of these procedures. To examine the accuracy of the results yielded from the M5 and GP procedures, two performance indicators (determination coefficient (R2) and root mean square error (RMSE)) were used. The comparison test of results clearly shows that the implementation of M5 technique sounds satisfactory regarding the performance indicators (R 2 = 0.944 and RMSE = 0.126) with less deviation from the numerical values. In addition, M5 tree model, by presenting relationships based on liner regression, has good capability to estimate the depth of scour abutment for engineers in practical terms.

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