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The World’s Most Destructive River

riverLandscaping erosion in residential areas is nothing compared to what is happening to a gorge in Taiwan.

According to geologists and land surveyors, a natural gorge is eroding at an unprecedented speed. The rate at which it is eroding would traditionally be seen over the course of a thousand years. Instead, the erosion process is taking place in just a few decades.

The natural phenomenon is being called “downstream sweep erosion.”

A recent study on the Taiwanese gorge was published in the Nature Geoscience journal and explained that the gorge formed after a major earthquake in 1999 lifted a large amount of earth more than half a mile. The turmoil resulted in the Daan river being cut off from the area. The river was then forced to forge a new pathway through the valley, causing extensive erosion.

Erosion damage in homes functions similarly to erosion occurring in nature. For example, floodwaters in both residential areas and in the natural environment both create damage and affect the surrounding environment depending on how severe the floodwaters are. If an area floods regularly during the spring, for example, residents should have their basement waterproofed to avoid costly water damage. This waterproofing amenity is not available for the gorge in Taiwan.

“In terms of river erosion, the Daan river gorge in Taiwan is extremely rare,” said Kristen Cook from the German Research Centre for Geosciences in Potsdam.

The phenomenon lies in the fact that the gorge forces the river to bend a complete 90 degrees, said Cook. The Daan River then rides the wall of the gorge, creating a dangerous water slide in it’s search for a shorter route through the gorge. Due to physics and how particles such as sediment and small pebbles travel faster when they are propelled through a circular path, the sideways flow is extremely abrasive — causing severe erosion.

This endless belt of sandpaper causes the Daan to erode the gorge’s upstream wall at an estimated 56 feet a year. Cook and her research team have therefore concluded that at this rate, the gorge will be nonexistence 50 years from now; it will be nothing but wet sand at the bottom of the river.

“As the upstream boundary of the gorge keeps moving downstream, the gorge will get shorter and shorter until the upstream boundary reaches the exit of the gorge, and the whole thing is gone,” Cook explained.

In it’s place, a wide floodplain will exist which will be filled with smooth, fine sediment and polished stones. Cook plans to monitor and study the phenomenon in great detail over the next decade, as not every day geologists are given this rare opportunity to see erosion damage at it’s finest. No erosion control will be able to prevent the inevitable flood plain.

Erosion control prevents and controls wind or water erosion mostly in agriculture, land development, coastal areas, riverbanks, and construction.



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