гамшгийн үеийн ус хаюур
катастрофический водосброс
An auxiliary spillway designed to pass a large, but infrequent, volume of flood flow, with a crest elevation higher than the principal spillway or normal operating level.
Source Guidelines on Instrumentation on Large dams by Central Water Commission Ministry of Water Resources, River Development & Ganga Rejuvenation Government of India, June 2017, p.73