Is The Three Gorges Dam To Blame For Extreme Drought In The Lake Poyang Area? By Mu Lan Editor Chinese Three Gorges Probe May 2014 PROBE INTERNATIONAL Probe International 225 Brunswick Avenue, Toronto, ON, Canada M5S 2M6 Tel: (416) 964-9223 Fax: (416) 964-8239 journal.probeinternational.org 1 Drought At Lake Poyang As has been widely reported, Lake Poyang – China’s largest freshwater lake, located on the southern bank of the Yangtze River in southeastern Jiangxi Province – has been struck by a devastating drought. According to the province’s Xingzi Hydrological Station, on November 14, 2013, the lake’s water level dropped to 7.99 metres above sea level. This ranks as one of the lake’s lowest water levels recorded in decades, compared to a normal water level of 12.22 metres the previous year. According to experts at the Jiangxi Research Institute for Water Resources – a government department under the Water Resources Bureau of Jiangxi Province – when water levels drop to below 10 metres in the fall this signals the arrival of the dry season and if water levels drop below 8 metres this signals the appearance of extremely low water levels. According to a November 14, 2013 Xinhua report, satellite images revealed that Lake Poyang’s total water surface area shrank by 90% from 2,822 km2 on August 7, 2013, to 1,375 km2 on November 5, to only 293 km2 on November 14. As the editor of Probe International’s Three Gorges Probe Chinese language news service, I travelled to the Lake Poyang area twice in early November 2013 to observe the situation for myself. Standing on the Lake Poyang viewing pier near the county seat of Xingzi, close to Jiujiang, the second largest city in Jiangxi Province, I saw that most of the lakebed was exposed, while an abundance of tall grass and wildflowers had grown up everywhere. Dead fish, dried mussels and snails littered the dry lake floor, while groups of cows leisurely enjoyed fresh grass growing in the former lakebed. “Where is Lake Poyang?” I asked Mr. Yu, the driver I had hired in Jiujiang City. Pointing to the wild “grassland,” he exclaimed: “This is Poyang! Poyang is just below your feet!” “But why don't I see any water?" I asked. "Ha! Ha!” he responded. “Of course there is lots of water, and the water is everywhere! Unfortunately, not now, but in summer you would see the water this high," he said, pointing towards the shore. True. I saw the telltale wavy lines produced by seasons of rising and falling water levels spanning years. Is The Three Gorges Dam Responsible For The Extreme Drought In Lake Poyang? I believed I had truly hired the right person to drive me to Lake Poyang when I discovered Mr. Yu was a good talker, and that he was also familiar with the area and knew many things about Lushan (Lu Mountain) – located in the northern part of Jiangxi Province and one of China’s most famous attractions. He was well versed on the area’s local history, its ancient architecture and historical figures, and, of course, Lake Poyang. He told me that there is always a dry season every year in Poyang, but in recent years the dry season has arrived earlier and drought conditions have become worse. “As I understand, the Three Gorges is responsible for this," Mr. Yu told me. "Are you sure?” I said. “But the dam is almost one thousand kilometers away from here.” He replied: "I am not an expert in this topic, but everybody says that here. There has been lots of discussion on the Internet, especially on the local BBS (bulletin board service). If you watch TV, read newspapers or surf the Web, you will get tons of information on this.” Probe International 225 Brunswick Avenue, Toronto, ON, Canada M5S 2M6 Tel: (416) 964-9223 Fax: (416) 964-8239 www.probeinternational.org 2 Of course, there is no shortage of coverage on the subject in the Chinese media. On November 7, 2013, the Economic and Financial Channel under the banner of the state-run CCTV (China Central Television) broadcast a special program on the issue. The program gave three major reasons for the sharp decline of Lake Poyang’s water levels: first, there had been no precipitation for a month (based on records provided by Jiangxi’s Poyang Hydrological Bureau, the last day of rain was October 7, 2013); second, the uncurbed dredging of Poyang’s lakebed for its premium quality sand; and third, but no less important, the impounding of the Three Gorges Dam reservoir located upstream on the Yangtze River. The findings of hard-working local experts investigating the issue lend technical support to the conclusions of the CCTV report. Based on a November 6, 2013 report posted by the Jiangnan Urban Daily (Jiangnan dushi bao), a study conducted by the Jiangxi Research Institute for Water Resources described the impact of the Three Gorges Dam operations on Lake Poyang as follows: “The water levels in Lake Poyang are not significantly high while the dam project is discharging water from its reservoir in the flood season, but the water levels are really low in Lake Poyang while the dam is impounding water in the dry season.” As the study explained, the Three Gorges Dam’s operating regime – storing water to generate electricity and releasing it to provide flood storage capacity – has its most significant impact on the lake during the impoundment period from September to October each year. This period coincides with naturally occurring seasonal declines in both the Yangtze River and Lake Poyang’s water levels. From November to the following January and February, Poyang’s water levels regularly decline because the five rivers that feed the lake – the Gan, Fu, Xin, Rao and Xiu Rivers – are also receiving less water from their upstream watersheds. Though Poyang has reduced water flowing into it in this period, because the Yangtze’s water levels downstream of the dam are significantly lower during the dam’s impoundment period, the waters of Lake Poyang, are still relatively higher than the Yangtze. As a result, Lake Poyang drains into the Yangtze, making the loss of lake water and subsequent drought all the more severe. For example, according to data recorded by the Hydrological Bureau of Jiangxi Province, at 8 a.m. on January 2, 2012, the total inflow from the five rivers that feed Lake Poyang measured only 732 m3/s in volume, while the lake’s outflow into the Yangtze was as much as 1,280 m3/s, thus causing a sharp decline in Poyang’s water levels. The study also revealed that the colour of both the Yangtze River and Lake Poyang was entirely different before the Three Gorges Dam began its impoundment in 2003: the river typically appeared muddy while the lake was clear, a fact clearly visible in the county seat of Hukou (Hukou means lake mouth in Chinese, where the river and the lake join each other). At present, although the contrast is still as obvious, the situation has reversed itself: in the dry season of each year, the river is clear and the lake is muddy. According to experts at the Jiangxi Research Institute for Water Resources, one of the major reasons for this is that almost half of the lake’s water now flows into the Yangtze. The hydrogeomorphology is as follows: In general, both the river and the lake have experienced natural seasonal changes in colour; muddy in the flood season and clear in the Probe International 225 Brunswick Avenue, Toronto, ON, Canada M5S 2M6 Tel: (416) 964-9223 Fax: (416) 964-8239 www.probeinternational.org 3 dry season. This is so because the flow is greater in the flood season and the sediment carried in that flow is also much greater (compared to the dry season). Under natural conditions, Lake Poyang would be clearer than the Yangtze River in both the flood and the dry seasons because the water from the five upstream rivers (the Gan, Fu, Xin, Rao and Xiu rivers) flows into the lake and gradually deposits its sediment load in the lake. That changed, however, with the construction of the Three Gorges project, especially in the dry season. Since the Three Gorges Dam’s operations began, the annual impoundment of water behind the dam begins in middle to late September,i after the flood season, and the reservoir reaches its highest level in November of each year. As a result, the flow of water in the middle and lower reaches of the Yangtze during this period, below the dam, has been drastically reduced, causing much lower water levels downstream when compared to the natural flow regime that existed before the dam was built. Furthermore, under natural conditions, the Yangtze River flowed into Lake Poyang in the rainy season (from July to September), swelling the lake and, in the dry season, Lake Poyang flowed into the Yangtze (from September to January). Though that same seasonal water transfer still exists, after the Three Gorges Dam began operating, the rate at which water flowed back and forth between the river and the lake changed dramatically. Now, during the rainy season, the Yangtze flows into Lake Poyang at a greatly diminished rate, while in the dry season, because water levels in the Yangtze are so low, the flow rate from Lake Poyang into the Yangtze is much greater. According to experts in Jiangxi Province, from mid-September to mid-November 2013 – the dry season – almost half of Lake Poyang’s water flowed into the Yangtze, much more than would have occurred prior to 2003.