The Environment Effect of Bank Erosion in Three Gorges Reservoir Water-level-Fluctuating Zone

The Three Gorges Reservoir (TGR) is the largest hydropower dam in the world which plays a significant important role in China. After it run normally for the water level fluctuating from 145 to 175 m, there is a water-level-fluctuating zone with the area about 369 km². In this zone, the ground is submerged about 100 to 150 days per year and plants could not survive during the long time. And it bring a lot of problems including the bank erosion, water pollution, environment threaten, and harm for living conditions.

At summer, water-level-fluctuating zone exposed under sunshine. Little vegetation is sparse in the zone which leads to the dissolution of heavy metals from the soil to the reservoir water. At the same time, nitrogen and phosphorus release from the soil at bank and contributed to the reservoir water eutrophication.

Drag anchor mesh mat technology is present as ecological restoration method for water-level-fluctuating zone. Flume experiments prove that the mat could reduce the soil erosion obviously and support the base for the vegetation rooting and fit the flow condition of water-level-fluctuating zone. With the grass growing in the mat, the amount of heavy metals and eutrophication materials dissolving from the soil to the reservoir water could reduce and fishes in water could find habitable place to live in.