Across China: Nature-imitated fishway to meander through hydro project in Guangxi

Source: Xinhua| 2018-11-13 14:14:48|Editor: Liu
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NANNING, Nov. 13 (Xinhua) -- With all the twists and turns and stones of all sized piled along the bottom, a fishway in a large hydropower station in south China's Guangxi Zhuang Autonomous Region looks nothing like an artificial passageway for migrating fishes.

Located in the upstream of the Pearl River, the Datengxia hydropower project under construction aims to generate over 6 billion kilowatt-hours of clean electricity every year once completed.

It will also greatly reduce the risk of flooding in the downstream, promote shipping and irrigation and optimize the allocation of water resources.

The Datengxia, however, is an important fish habitat due to its complex flow conditions.

"We can build a dam to stop the river, but we should not stop fishes from migrating to spawn. Those fishes are the true owners of the river after all," said Yang Qixiang, general manager of the Datengxia Water Conservancy Development Co., Ltd.

Yang said a rare dual fishway design for both the main dam and the auxiliary dam was therefore put forward at the very beginning of the construction.

At the building site of the auxiliary dam in Nanmu River, not very far from the main dam, the original design for the fishway has been replaced by a creative scheme that imitates nature to the greatest extent.

"Instead of a straight and flattened channel made of ordinary concrete, we used stones to create winding pathways of various widths," said Yan Laiguang, an engineer.

The total length of the fishway is about 2,500 meters with a maximum drop of about 24 meters. Yan said several pools were added on the way to create a fish ladder. A fish breeding station and a rare fish conservation center are also integrated into the fishway.

In the meantime, designers are working on the final numerical simulation of water flow and adaptive verification of migrating fish to make sure the fishway will truly function upon completion.

"The revised design is more favorable for fish migration, and, of course, more costly and increases construction difficulty. But still, it's worth it," said Yang.