New insights into the design and performance of combined weir-gate hydraulic structures, a crucial component of modern water-management systems, are discussed in the International Journal of Hydrology Science and Technology. Weir-gate hybrid structures merge the functions of a traditional weir and a sluice gate and are now being widely used to regulate water flow, control flood risks, and aid in flow measurement.
Noor I. Khattab, Azza N. Altalib, and Arwa A. Mullah of the University of Mosul, Mosul, Iraq, have now looked at a novel design for such structures, which incorporates a triangular shape with interior angles that can range from 60 to 180 degrees. Their findings explain how the configuration of these structures impacts their efficiency in managing water flow.
A weir is typically used to direct water over a barrier to control flow, while a sluice gate is designed to regulate flow beyond the barrier. By combining both functions into a single hybrid structure, engineers can maximize the benefits of each. The new work demonstrates how varying the angle within a triangular opening affects the flow of water and the efficiency of discharge measurement. The team used a key performance indicator, the discharge coefficient, is used to quantify the efficiency of the structure in controlling and measuring flow.
The researchers found that as the interior angle of the hybrid structure decreases, so the discharge coefficient increases. Under constant upstream head values, the discharge coefficient showed an average increase of 27% to 54% as the interior angle became more acute. The study also found that the shape and configuration of the structure, including the length of the crest and the specific type of flow, whether it flows over, under, or through the structure, affect overall performance. One of the important applications of these hybrid structures is the reduction of sediment accumulation beneath gates. The weir pushes materials out while the gate controls flow.
Weir-gate structures play a role in managing water: flood control, irrigation, water supply, and energy generation. If the design of these structures can be improved and optimized for specific purposes, then efficient and cost-effective infrastructure might be developed that is better equipped to handle fluctuating water conditions.
Khattab, N.I., Altalib, A.N. and Mullah, A.A. (2025) ‘Hydraulic characteristics of combined weir-gate structure’, Int. J. Hydrology Science and Technology, Vol. 19, No. 5, pp.1–17.