Why engineers build small dams that do not store water

A weir is a specialized hydraulic structure built across rivers to manage water levels rather than store it. This video explains how these structures function and why they remain a fundamental tool for controlling water flow in streams and rivers.

While large dams are designed to create reservoirs for storage, a weir serves a different purpose: gaining precise control over upstream water levels. These structures have been utilized for ages to manipulate the flow of water in various bodies.

In modern engineering, the definition has expanded to include any hydraulic control structure where water flows over the top, known as the crest. This design is so effective that the spillways of many massive dams incorporate weirs as essential control mechanisms.

Source: What is a Weir?