Flooding Rivers: How to Go With the Flow
Li Jian, Corbis
July 24, 2012: The heaviest rainstorm to hit Beijing in six decades started on Saturday afternoon, July 21, and continued until Sunday morning when blue skies returned. The inundation left at least 37 people dead. Torrents of water streamed into homes and car parks during the deluge. The disaster provoked many to question whether the city infrastructure was equipped to handle flooding.
ANALYSIS: Did Beijing Build Too Fast?
In this photo, members of China's paramilitary troop evacuate flood-affected residents in Baisha Township, Jiangjin District, southwest China's Chongqing Municipality, on July 23. In Jiangjin District, situated upstream from the city proper of Chongqing along the Yangtze River, more than 40,000 residents have been evacuated. In all, the flood has affected some 300,000 residents within Chongqing's periphery.
Deng Liangkui, Corbis
Citizens watch the flood peak of the Tuojiang River, a distributary of the Yangtze River, on the Tuojiang Bridge in Luzhou City, southwest China's Sichuan Province, July 23, 2012. Due to continuous rainfall, the highest water level of the Luzhou section of the Yangtze River, China's longest, reached 19.62 meters on Monday, only 0.34 meters lower than the hundred-year flood happening in Luzhou in 1948.
A cyclist rides on a flooded street during heavy rainfall in Beijing, China. On the afternoon of July 21, around 4pm, Beijing received the heaviest torrential rains in six decades as the daytime sky turned black as night. Beijing city's meteorological observatory issued a torrential rainstorm orange warning signal. Due to surface flooding in many sections, some city streets were essentially broken.
ANALYSIS: Huddled in Beijing as Killer Storm Strikes City
On July 22nd morning, divers found three dead bodies at the Nangangwa section of Beijing-Hong Kong-Macau Expressway. In total the rainstorm left 37 people dead according to the official report. Since too much water had been collected at the section, reportedly 6 meters deep at its deepest spot, the authority said they would need 4 days to pump water. Rescuers arrived at the waterlogged area where dozens of vehicles were submerged and piled up, to put on their flippers and oxygen tanks to search underwater for more dead bodies.
Vehicles are trapped in the heavy rain causing a severe traffic jam in Beijing on July 21, 2012.
ANALYSIS: Hover Car Is No Hallucination
Zhang Yu, Corbis
Rescue workers clear mud on the Nangangwa section of the Beijing-Hong Kong-Macao expressway in Beijing, capital of China, July 24, 2012. Two-way traffic in the flooded Nangangwa part of the expressway had been resumed since Tuesday noon, after a torrential rainstorm hit Beijing on Saturday. The rainstorm, purportedly the worst in 60 years.
Li Wen, Corbis
A boy carries his rain-soaked baggage as he is evacuated from a flood-surrounded military training site in Fangshan District of Beijing on July 22, 2012. About 350 students and 60 teachers trapped at the training site by rain-triggered flood on Saturday night were transferred to safe areas on Sunday morning.
Deng Xianping, Corbis
A firefighter transfers a trapped resident in Zhutuo Township of Yongchuan District, southwest China's Chongqing on July 23, 2012. Flood hit Zhutuo Township on Monday morning. After four hours' rescue, altogether 128 trapped residents had been transferred to safe place.
Luo Xiaoguang, Corbis
Trees are seen after the rainstorm at Daxinzhuang Village of Zhangjiawan Township, Tongzhou District, Beijing, July 22, 2012.
ANALYSIS: DC Derecho Disaster Explained
The solution to more frequently flooding rivers in the Midwest isn't to fight it with more and higher levees, but to flood more land, say ecologists and water managers. The record floods along major rivers of the U.S. Midwest don't have to be disasters and can be turned into opportunities to benefit many native plants and animals while saving towns from floodwaters.
The accidental over-topping of one particular levee last week along the Illinois River has given The Nature Conservancy and researchers an opportunity to study just how the deliberate flooding of some lands might be the solution.
“We're just seeing this record breaking floods over and over again,” said Michael Reuter, director of The Nature Conservancy's North America Freshwater Program (see his video blog). Climate scientists have long predicted as much, he said. “The 100-year flood will happen more frequently than that name would suggest. It's time for a different approach. We can't keep building higher and higher levees.”
The Illinois River itself tried a different approach when it spilled about 2 billion gallons of water into the Emiquon Preserve last week. That prompted the preserve managers to wonder what would happen if they had a floodgate on their levee and had deliberately let in a lot more water?
“We could reduce flooding nearby by several inches or several feet,” Reuter said.
A similar benefit was observed when a levee failed at another Nature Conservancy preserve at Spunky Bottom on the Upper Mississippi in 1993, said water resources researcher Richard Sparks of the University of Illinois. The benefits for nature are that the deliberate flooding can mimic seasonal moderate flooding events, to which many native species are adapted, he explained. These same species are struggling with the epic floods now underway, which have little in common with the floods they evolved with.
“There is a difference between seasonal floods and these,” said Sparks. “These bigger floods are less frequent like we are having now on the Illinois River. They help some species and hurt others. In all these (preserves) what we are trying to do is recreate natural flooding regimes." That's important because the natural regimes have already become distorted by climate change, he said. On the Illinois River water levels are much more erratic than they were naturally.
By seasonally flooding nature preserves – as well as farmland, where farmers have agreed to it – both excessive flooding and drought conditions can be moderated, Sparks said.
The plan would cost money of course, but Reuter argues that's really beside the point since the cost of flood damages to towns and river commerce are already astronomical.
“The question is not whether we spend money, but are we spending it wisely,” Reuter said.