Tag: water quality

Dongjiang Expedition Part 4: The perils of small hydropower

Small hydropower, roughly defined as having 300 kilowatts to 30 megawatts of electricity generation capacity,  is often lauded as a low environmental impact solution for rural electrification.

In some cases, small hydropower may be useful and sustainable.  However, like large hydropower, its deployment must be planned carefully.  Small hydropower plants with reservoirs cause the same type of damage dealt by larger plants, including flooding of productive land, fragmentation of river ecosystems, and alteration of natural flows.

In-stream hydropower plants, which don’t require reservoirs, generate electricity by diverting water from the natural stream into sloped pipes that lead to turbines.  An important requirement for sustainable operation of in-stream hydropower plants is the maintenance of minimum ecological flow in the natural stream.

The over-deployment and poor planning of small hydropower has irreparably destroyed river ecosystems all over China, and Guangdong Province is no exception.

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Dongjiang Expedition Part 1: The meaning of “free-range”

You may recall that awhile back, I participated in an expedition to explore the watershed of Dongjiang River, the source of 80% of Hong Kong’s water supply.  Over 90% of the watershed’s land area is in Guangdong Province, while the remainder is in Jiangxi Province. As you can see from the route map above, we traced the river from its mouth (lower right) at the Pearl River Delta (虎門) up to its source (upper right) in the mountains of southern Jiangxi.

Through written treaties, China has promised to provide a continuous supply of Dongjiang water to Hong Kong as well as maintain Dongjiang’s high water quality.  Despite these promises, many are skeptical of China’s sincerity.

For several reasons (first, political sensitivity, then, laziness), I’ve held off on posting about that expedition…until now.

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