Severe flooding has taken place along China's Yangtze River over the last three weeks, affecting the same provinces that were devastated by last year's floods.
According to the International Red Cross, more than 50 million people across six provinces have been impacted, with 240 people already confirmed to have died, and 1.8 million forced to flee their homes. Over 400,000 houses have collapsed and another one million are damaged. For the second year in a row, thousands of hectares of farmland have been inundated and crops ruined. Damage estimates already total more than $US3 billion.
As was the case last year, a significant factor in the height of the flood peaks on the Yangtze is the fact that upstream catchment areas, in particular the Dongting Lake, are overflowing.
The storage capacity of natural water catchments across China has been dramatically reduced due to unplanned land reclamation, untreated silting and dumping of industrial waste. Estimates published last year by the Chinese State Environmental Protection Administration revealed that the storage capacity of Dongting Lake had fallen from 29.3 billion cubic metres in 1949 to only 17.8 billion cubic metres.
This year's flooding could seriously affect Shanghai and its surrounding townships, one of China's most important commercial and industrial centres. Water levels in the Lake Taihu basin continued to rise over the last week after torrential rains dumped three times the expected rainfall.
Flooding of Lake Taihu was responsible for major damage in the region in 1991. In its aftermath sluice gates were built to control water flows. Their effectiveness will be put to the test over coming weeks.
Emergency measures are also underway to control overflows of the Yellow River. As with the Yangtze, reclamations and silting have drastically increased the threat of flooding. Hundreds of embankments built within natural catchment areas have caused the riverbed to rise by 2-4 metres in its lower reaches. Water now flows at only 50 percent of its rate further upstream.
Officials have estimated that this year's rainfall will be 30-40 percent higher than average and raised concerns about the lack of effective levees and pumping equipment. More than 35 percent of the levees along the Yellow River do not meet the required technical specifications or height to withstand major floods and are predicted to fail. Zhongyuan Oilfield, one of the country's most important, is directly threatened.
The implications in human terms are staggering. According to Water Resources Minister Wang Shucheng, the levees along the Yellow River do not protect all of the threatened land, with 78 million people exposed to any particularly severe flood.
In its assessment of last year's floods, which cost 4,150 people their lives and inflicted $US30 billion in damage, the Water Resources Ministry, in a report “examined and approved by the higher authorities of the central government,” placed the blame primarily on abnormal climatic conditions causing historically high levels of rainfall.
There is no question that China has experienced an unusual climate in recent years. Throughout Chinese history though, such exceptional periods of rainfall that have produced devastating floods, especially along the Yangtze. The most severely affected have always been the poorest layers of the peasantry.
The most serious flood this century occurred in 1954 and left tens of thousands dead. In it aftermath, promises were made that when China did experience the next period of unusual climatic conditions, flood control measures would protect the population from the fate of previous generations.
What is being revealed now is that the inevitability of major flooding was ignored over successive decades by the Beijing regime. Apart from the far-reaching degradation of the natural catchments, much of the construction done in the 1950s and 1960s is proving to be worse than useless.
The crisis in man-made dams is potentially disastrous. Experts at the Water Resources Ministry have condemned over 33,000 dams across China as defective and requiring urgent repairs.
This represents one out of every three dams built as part of flood control measures. Their construction coincided with episodes like the “Great Leap Forward” of the late 1950s, when all concerns for the integrity and quality of economic activity were sacrificed to meet bureaucratically-imposed production targets.
Instead of these dams functioning as effective water catchments helping to avoid flooding, China has been left with what are described as “time-bombs,” vast concentrated volumes of water held in by crumbling dam walls. Over 20,000 people drowned in 1975 when two such dams collapsed in Henan province.
Last year's floods showed that levees in many areas are not high enough for 40-year high water marks or were poorly built and suffered severe structural damage. Emergency repairs have been required to more than 6,000 kilometres of levees, including to a major dike protecting the industrial city of Wuhan in Hubei province.