Seite - 330 - in Book of Full Papers - Symposium Hydro Engineering

STUDY ON THE SEDIMENTATION CHANGES IN THE MANWAN RESERVOIR ON THE LANCANG RIVER* Pang Bohui, Li Mengyang*, Lu Ji, Chen Hao Technology R&D Center, HUANENG LANCANG RIVER HYDROPOWER ITD. CHINA 1. INTRODUCTION The Lancang - Mekong River, originating from the Tanggula Mountains in Qinghai-Tibet Plateau of China, flows from north to south successively across Qinghai, Tibet and Yunnan in China, and then Myanmar, Thailand, Laos, Cambodia and Vietnam. It empties into the South China Sea to the west of Ho Chi Minh City of Vietnam. The Lancang River has a river length of 2100km, and a drainage area of 17.4×104km2. 23 cascade hydropower plants have been planned with a total installed capacity of about 32 million kWh. At present, six cascade power plants have been built on mainstream of the middle and lower reaches of the Lancang River, which are successively downstream Gongguoqiao, Xiaowan, Manwan, Dachaoshan, Nuozhadu and Jinghong. And now the Lancang River is the only north-to-south cross-country river that has been totally developed in China. Changes in hydrology and the ecological environment of an international river due to the hydropower development are now drawing more and more attention internationally. One major problem is the sedimentation caused by dams, which have influences not only on the reservoir operation， but also on the migration and transformation of the biogenic substance including carbon and phosphorus in the river. For this reason, it is very important to study the sedimentation problem of the Lancang River due to damming, evaluate and predict the problem scientifically and provide a theoretical foundation and data support for studying the reservoir operation and the ecological environment *titre de l'articlecomplet 330