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A notch weir is any weir where the physical barrier is significantly higher than the water level except for a specific notch (often V-shaped) cut into the panel. At times of normal flow all the water must pass through the notch, simplifying flow volume calculations, and at times of flood the water level can rise and submerge the weir without ...
Roller dams are a type of weir, or a dam that is designed to allow water to flow over the top in continuous action. They are used on rivers or other such moving bodies of water where erosion damage is undesirable, yet likely to occur. A short wall, lip, or parabolic channel is constructed on the downstream side of the dam parallel to the dam face.
A drop structure, also known as a grade control, sill, or weir, is a manmade structure, typically small and built on minor streams, or as part of a dam's spillway, to pass water to a lower elevation while controlling the energy and velocity of the water as it passes over.
A waste weir on a navigable canal is a slatted gate on each canal level or pound, to remove excess water and to drain the canal for repairs or for the winter shutdown. [1] This differs for a dam or reservoir, for which a waste weir is another name for a spillway , i.e. not having the boards to adjust the water height nor the paddles to drain ...
Weir on Lake Tecumseh, Virginia. A flow control structure is a device that alters the flow of water in a stream, drainage channel or pipe. As a group these are passive structures since they operate without intervention under different amounts of water flow and their impact changes based on the quantity of water available.
The tilting weir has its origins in the 19th century drum weir which functions using the same principles as the 20th century design. The drum weir, was for a long time confined to the River Marne, where it was first introduced in 1857. [5] Early tilting weirs were constructed from wrought iron and wood.
Stepped spillways, consisting of weirs and channels, have been used for over 3,500 years since the first structures were built in Greece and Crete.During Antiquity, the stepped-chute design was used for dam spillways, storm waterways, and in town water supply channels.
In hydraulic engineering, a nappe is a sheet or curtain of water that flows over a weir or dam. The upper and lower water surface have well-defined characteristics that are created by the crest of a dam or weir. [1] Both structures have different features that characterize how a nappe might flow through or over impervious concrete structures. [2]