The filling to capacity of the Three Gorges Dam is being hailed by officials as a success. They have good reason to be effusive with praise: it is an achievement that was tried twice before then abandoned, first after landslides and then protests. For an hour on Tuesday, though, the maximum 175-metre mark was reached without a hitch, allowing for all 26 hydroelectric generation units to produce power for the first time. That is without doubt a landmark, but it is too early to declare that the long-dreamed project and lesser ones of its kind are a triumph.
Three Gorges is, of course, an engineering marvel. There is no other dam in the world that can match its dimensions or electricity output. At capacity, the Yangtze River is backed up to create a 600-kilometre reservoir. But whether it can prevent the worst floods - the other reason for its construction - remains uncertain.
Authorities cannot say for sure what is the dam's real impact on surrounding slopes and downstream communities and ecologies. Slopes have been stabilised but water seepage could still weaken hills, and cause slippage. With the river beyond the wall down to half its usual flow, complaints abound about shipping that has been affected. Higher levels of salinity have been reported and that is of concern for fisheries, farmers, cities and towns. There is also the matter of earthquakes - some scientists contend that the dam's volume is adding to stress on tectonic plates in the region.
Just how severe the problems are is not clear. There has been a lack of openness and transparency about the dam and at least two dozen others being built or planned elsewhere in the nation. Their construction means that people have to be uprooted and relocated; just how many are involved is not precisely known. Scenery, habitats and history are destroyed. And yet there is little real scrutiny of these projects because of political sensitivities.
The Three Gorges Dam set the tone. It has been the dream of Chinese leaders since Sun Yat-sen, the father of the modern nation, more than a century ago. Only in 1992 were plans approved, and construction began two years later. The project has been so politically sacred, even since it was completed four years ago, that objections and criticisms are voiced only very warily.
There are good reasons for such projects. China needs electricity for its development, and hydropower from dams is the cleanest way of producing it. Their construction has also fed into efforts to control floods that from time to time wreak havoc on riverside cities and towns. The Yangtze has been of particular concern, with 4,000 people being drowned in 1998. Amid flooding in July, doubts were raised about whether the Three Gorges Dam would hold back the waters. It did, and now the wish of capacity has been attained.
But these achievements have to be balanced against the unknowns. Success has been declared, despite it being too early to make such an assessment. With other mammoth projects in the works, it is in everyone's interest that there be much more transparency about how this, and other dams, are faring.