The Yellow River Delta
The river at present debouches north of the Shangdong peninsula.The primary cause of these rapid shifts has been the heavy load of silt carried by the Yellow River.As the current slackens near the sea,much of this is redeposited,building up the riverbed and sooner or later forcing the water to run elsewhere.The present multi-exit system seeks to avoid this by the regular dredging of the channels temporarily taken out of use.Some 1,600 million tons of China goes down this river each year.Close to 1,000 square miles of new land has been formed by this silt.
The Yellow River,China's second largest,has shed nearly 200 million tons of sand in the past two years,said Li Guoying,deputy director of the Yellow River Water Resources Committee,here Thursday.The loss had increased the river's flow by 100 to 400 cubic meters per second,Li said at the National Conference of Water Resources Directors.The committee organized sand washing operations in July of 2002 and September of 2003 by discharging speeding currents from the massive Xiaolangdi Reservoir on the lower reaches of the river,successfully carrying 187.1 million tons into the sea.
The reservoir had prevented some 900 million tons of silt from flowing to the lower reaches since it started storing water in October,1999.However,the build up of silt in the lower reaches of the river was still severe,with 400 million tons filling the riverbed every year.The silt had built up a new riverbed,known as the "second hanging river" by the locals,on top of the original riverbed,on the lower reaches from Kaifeng to the mouth.