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Analysis of extreme hydrological events in a monsoon climate catchment: the Hongru River, China

Author:
HØYBYE, JAN, IRITZ, ZLÔ
Source:
Hydrological sciences journal 1997 v.42 no.3 pp. 343-356
ISSN:
0262-6667
Subject:
climate, dams (hydrology), hydrologic models, monsoon season, rivers, runoff, storms, uncertainty, watersheds, China
Abstract:
In August 1975, an extraordinary storm hit the Hongru River basin in Henan Province, China. Two dams were overtopped, breached and totally destroyed and the river basin experienced a severe flood. Various methods for assessing the return period of the peak discharges and changes in hydrological response due to the dambreak have been investigated: Annual Maximum Series (AMS), Partial Duration Series (PDS) and regional analysis. The three approaches gave different estimates of the T-year discharge event and of the observed 1975 event, which leads to the question whether probability-based methods are applicable for very extreme events. Although not capable of giving consistent estimates, extreme value analysis shows that the catchment response has changed because of the dambreak in 1975, which change in turn can be used for future designs. The uncertainty in the estimated design peak flows suggests that probability-based estimation methods for extrapolation should be complemented with research into historical events and simulations based on rainfall-runoff models.
Agid:
6315364