What is the primary function of a weir in drainage systems?

The primary function of a weir in drainage systems is to control the flow of water and measure its rate. Weirs are barriers placed across open channels that allow water to flow over them in a controlled manner. As water flows over the weir, the height of the water above the crest provides a means to calculate the flow rate. This is vital in assessing drainage capacity, managing water levels, and ensuring that systems operate efficiently.

By monitoring the flow rate, engineers and drainage professionals can make informed decisions about water management, optimize designs, and implement necessary adjustments in the system to prevent flooding or ensure adequate drainage. The ability to control and measure flow is crucial in maintaining the overall function and safety of drainage systems.