the.com/spillway
a dam's emergency exit, designed to flood politely instead of catastrophically.
means A channel or structure that lets excess water flow safely past or over a dam or reservoir, preventing it from overtopping and failing.
from A plain English compound of "spill" + "way" — literally a "way for water to spill." "Spill" comes from Old English "spillan," meaning to destroy, shed, or waste (its watery sense came later), while "way" is the ancient Germanic word for a path or route, a cousin of Latin "via." The pairing is industrial-age plainspeak: as engineers built ever-larger dams, they needed a word for the deliberate route by which water is allowed to escape, and named it for exactly what it does.
- glory hole
- Circular spillways look like Earth's bathtub drain
- big leagues
- Some discharge more water than Niagara Falls
- erosion enemy
- A failing spillway can carve away the dam itself
- rarely used
- Many sit dry for decades between floods
hoover dam spillway — nevada-arizona border, can discharge 200,000 cubic feet of water per second
three gorges dam spillway — hubei province china, world's largest capacity at 110,000 cubic meters per second