38. Building Up to Catastrophe
The Yellow River carries massive amounts of silt – about 1.5 billion tons each year. Throughout most of China’s history, it was not dredged. The result was a steady accumulation of silt at the river’s bottom, causing the river bed to steadily rise. A rising river bed is bad news for those living and farming along its banks. The shallower the river gets, the wider it becomes, threatening to flood adjacent lands.
Much of China’s history has been about preventing that from happening, usually with massively labor-intensive projects to line the Yellow River with protective dikes. As the river rose over the years, so did the dikes. This went on for thousands of years, until China ended up with a river flowing along at an elevated level, often higher than the adjacent land. So when dikes failed, the results were catastrophic. With the Yellow River, floodwaters don’t gradually rise as occurs with most rivers. Instead, they come crashing down from on high, sweeping all in their path with great violence.
