Can the annual flood control volume at Three Gorges Dam be predicted to size a variable flood control pool?
Abstract:We consider the empirical prediction of the peak flood volume on the Yangtze River at the Three Gorges Dam. The dam is operated for flood control, hydropower production and irrigation. The flood control space reserved in the reservoir each year during the monsoon season limits the ability to supply hydropower and irrigation services. Allocating a variable amount of flood control space based on a pre-season forecast of the peak event flood volume, or of the flood volume over a specific duration is consequently, more useful than a prediction of the annual maximum peak flow for this dam and for other flood control dams.
The joint distribution of annual peak flow, the corresponding flood volume, and the event duration is investigated based on the copula theory. A statistical model is developed for the conditional prediction of this joint distribution using pre-season climate indicators. The potential for the guidance for water management in the Yangtze River basin and for insights to the design of the large flood control reservoirs in the future is illustrated.