Side weirs are structures used to control water flow in rivers. A trapezoidal labyrinth side weir was studied to see how well it diverts water. The researchers changed the water flow speed and tested different dimensions of the weir. They found that the trapezoidal labyrinth side weir can divert more water than regular side weirs, with a 15-30% increase in efficiency. The best angle for the weir is 30 degrees, which gives the highest water diversion rate. The weir works best with longer openings and taller heights.