The Regulation Of Three Gorges Dam On Lake Poyang: An Assessment Of The Lake Water Level Change During The Dry Season

With a combination of field data analysis and numerical simulation on 2D river-lake hydrodynamics, this study focuses on the water level change in Lake Poyang regulated by the Three Gorges Dam (TGD) during the dry season. Based on the long-term measured water level series (1956-2012), after the completion of TGD, the dry season in Lake Poyang is promoted to start early, and its duration is extended. With the regulation of TGD during the impoundment period, more outflow from Lake Poyang pours into the Yangtze River, leading to the decrement of lake water level and an earlier occurrence (about 4-5 days forward) of the dry season. Besides, with the regulation of TGD during the flushing period, the water level in Lake Poyang is elevated, making a relief to the lake drought during the dry season.