August 8th, 2010 began as a relatively normal day for the residents of Zhouqu County, China. It was a rainy day, which was unusual after an exceptionally dry nine months. By nighttime, the rain picked up into a torrential downpour. Between 8 p.m. and 10 p.m., the rain poured heaviest. Some Chinese officials estimated as much as 90 millimeters of rainfall in just that 2 hour period. Meanwhile, just above the town and its surrounding villages, catastrophe was barreling down.
At around 10 p.m., a temporary lake of flood water broke through its weak natural barrier and caused a massive mudslide. The mudslide rushed into the city and destroyed everything in its path. It also caught the citizens completely off-guard.
The next morning revealed the devastation. Buildings of all sizes were reduced to rubble, entire neighborhoods were buried, at least 1,200 people were killed, and thousands more were left injured or homeless. The Chinese government reacted quickly, and sent more than 10,000 people to aid in the rescue and recovery efforts. Government officials stated that the mudslide was an entirely natural, and thus unavoidable, disaster, but evidence suggests otherwise. The Chinese government is correct in stating that Zhouqu County was naturally susceptible to landslides, but they leave out their own role in exacerbating the impact of the disaster. This catastrophe was the result of a fatal combination of natural forces and negligence.
For many years it should have been clear that Zhouqu County was prone to landslides. The area had already experienced large-scale mudslides in 1978, 1989 and 1992, which collectively destroyed 842 houses, killed two people, and left 194 others injured. The county lies in a valley between a river and steep slope that is high in clay. Rivers are known to cause erosion and undercut mountainsides. Clay-based soil is particularly problematic because it becomes loose and loses friction when it’s too dry or wet, meaning its angle of repose can shift drastically depending on the weather.
Human interaction with the environment only added to the danger surrounding the county. Due to farming and logging, the once forested mountainside was left completely barren. From 1952 to 1990, roughly 100,000 cubic meters of forest was logged in Zhouqu County every year. Meanwhile, farmers cleared every bit of land that had a slope of less than 40 degrees to use for crops or grazing. By the time questions were raised about the effects of the deforestation, the soil quality had diminished and the slope could no longer support new trees.
In the five years preceding the mudslide, 41 hydroelectric plants were constructed along the Bailongjiang River. They were built so quickly that few people realized their effect. A week before the disaster, a plant was cited for incorrect waste disposal that was causing erosion for the first time. By that time, the plants had already collectively caused an estimated 749,000 tons of erosion. To allow for all of this construction, many roads were carved into the mountainside, which heavily undercut the slope.
All of this begs the question: How could the Chinese government not see this coming? The truth is, they did. In the 1980’s, a group of geologic experts surveyed the region and informed officials of the danger. They suggested that the entire county be relocated as a precaution. The government refused, believing it would be too expensive to move thousands of people, many of whom wouldn’t be able to afford a new home. In 2005, another study came to the same conclusion, and scientists strongly urged the government to spend the money necessary to protect the citizens of the county. Instead of making positive changes, the government went forward with rapid and erosive hydropower development.
In June 2008, geologists returned to the area following a powerful earthquake. They raised the same concerns, identifying more than 60 places in Zhouqu County where a landslide was likely to occur. The area experienced heavy drought during the first half of 2010, which dried and loosened the high-clay soil. When heavy rain and flooding occurred in August, conditions became perfect for a massive mudslide.
The citizens of Zhouqu should have been relocated years earlier, but even so, they still would have had plenty of time to escape on that fateful day had their government taken the proper steps. GPS technology could have monitored the mountainside and signaled the oncoming slope failure, and it seems almost crazy that it was not put in place after so many warnings.
The Chinese government has accepted little responsibility, and according to some residents of Zhouqu, they have significantly downplayed the devastation in order to save face. After totaling the population of the destroyed villages in the path of the mudslide, citizens estimated that there were nearly 10,000 casualties, nearly ten times as many as initially stated by the government. Little action has been taken to prevent similar disasters, and mudslides still kill many people every year in China and across the world. Geologists have now identified more than 200,000 hazard zones in China, very few of which have geological monitoring stations. If we can take away one lesson from this tragedy it’s this: history will repeat itself, so stay out of harm’s way.
Cover Photo: Image Source