Groins (spur dikes) are structures constructed at an angle to the flow in order to deflect the flowing
water away from critical zones. The main objectives of the study are to investigate the hydrodynamic impact of
oriented groin existence in a stream bed. A 2-D laboratory flume model was used. About 30 runs were carried
out for monitoring the impact of groin length, orientation angle, and the discharge on working length, and
velocity components. 28 measuring points were used for velocity measurements distributed as 4 lines from A to
D crossed by 7 cross sections. The study showed that the straight groin of 8cm (20% contraction ratio) has the
longest working length, however the repelling groin of angle of 600 and 4cm length of (10% contraction ratio)
presented the shortest working length. The velocity was decreased than the basic case at the nearest velocity line
to groin installation; however the velocity increased than the basic case for the rest lines. The velocity was
inversely proportional to groin length upstream and downstream groin location. The impact of groin orientation
angle on velocity was exclusive at lines A and B; however the impact was vanished after that at lines C and D.
Groin installation proved high efficiency in bank protection especially with high discharges |
