By Kim Robson:
The frequency of massive, deadly mudslides seems to be on the increase. In California last February, torrential rains triggered mudslides across the state. While mudslides are often a fact of nature, more often lately their cause is being traced to agricultural deforestation.
On Dec. 12, 2014, sixteen homes in Camarillo Springs, California, were destroyed when rocks and mud flowed downhill after heavy rains. The homes were smashed beyond repair, filled with debris up to the rooflines. Luckily, there were no serious injuries. The slide was attributed to a 2013 wildfire that left the rugged terrain bare of protective vegetation.
In 1995 and again in 2005, the town of La Conchita, California, had been buried under devastating mudslides, causing ten deaths, millions of dollars’ worth of damage, and displacing scores of other residents. The entire town has been declared a Geological Hazard Area by the County, thus severely restricting future building permits. While the slides have been connected to the larger Rincon Mountain megaslide, which started thousands of years ago, homeowners successfully sued the nearby La Conchita Ranch for damages. Located at the top of the slope, the ranch was found to have contributed to the area’s instability with their large-scale agricultural orchards and irrigation infiltration.
Then, like a horrible April Fool’s joke, on April 1st, 2017, a devastating flash flood sent thousands of tons of mud, giant boulders, and uprooted trees smashing through Mocoa, in southern Colombia. The death toll reached 293 people (many of them children), and hundreds more were injured or are still missing. Set at the confluence of six rivers, Mocoa had for years ignored dire warnings from government agencies, land use experts, and environmental organizations. The city continued to spread into the wet, subtropical-Amazon floodplains west of downtown.
“Unfortunately, in Colombia we don’t have a good assessment of risk, or good land use policies to prohibit people from settling in areas like these,” said Marcela Quintero, a researcher with the International Center for Tropical Agriculture, one of several organizations that had raised alarms about area deforestation in order to make room for cattle ranching and agriculture. Cutting down the rainforest removed natural protection against flooding and landslides.
Then a month’s worth of rain fell in a single night, and the long-predicted disaster arrived. Three of the six rivers surrounding Mocoa overran their banks. A wall of mud, car-sized boulders, and tree trunks ripped through the streets, destroying buildings and carrying away everything in its path.
President Juan Manuel Santos called it one of the worst natural disasters in Colombia, and the finger-pointing started quickly. The media pointed to a 1989 Ministry of Agriculture report which had outlined the exact scenario that happened, and recommended flood control measures be implemented.
When residents warned local officials three years ago that the Taruca River was overflowing onto people’s land and that the banks would soon burst, theywere dismissed as “paranoid.” “It was a tragedy foretold and the authorities didn’t do what they should have done,” one Catholic priest said. Even with the warnings, Colombia may not have been able to act because its resources were stretched terribly thin, having emerged only about a decade ago from intense violence and kidnappings due to its long civil war with drug cartels.
Santos, however, has now pledged to rebuild Mocoa and make it better than before. But more important are better land use policies aimed at preventing widespread deforestation in the first place. Established native vegetation is the best natural protection from flooding, and will be even more critical as climate change brings increasing rainfall in future years.