Spillway

A spillway is defined as a “passage for surplus water over or around a dam when the reservoir itself is full." A spillway is an important safety feature for dams; they work as a fail safe if the reservoir begins to overflow. They often sit at the top of the dam or a separate conduit around the dam, and have a channel that dissipates into some body of water, usually a river [1].

Spillway construction is very tedious because “inadequate spillway capacity caused failure by overtopping for many older earthen dams built before modern flood data became available." Having the wrong position and size of a spillway can mean that a whole area, or even a whole town can become overcome by flood water. Spillway construction is taken into account when the dam itself is being designed, because rain water and other factors have to be taken into account beforehand. Spillways are usually constructed using a similar material as the dam it is adjacent to, which is often concrete. Spillways are almost always made of a non-erodible material, as erosion can cause flow problems in the spillway defeating its purpose [1].

References

[1] Encyclopedia Britannica. (2017, July 28). Spillway. Retrieved (2021, July 20), from https://www.britannica.com/technology/spillway-engineering