MECHANISM AND EFFECT OF CHANNEL EVOLUTION AT ESTUARY OF WEIHE RIVER TO HUANGHE RIVER

The channel at the estuary of the Weihe River to the Huanghe (Yellow) River has changed markedly since the 1970s. The Huanghe River has swung westwards about 5km and there was retrogressive deposition along the Weihe River. The mechanism and effect of channel evolution at the entrance of the Weihe River to the Huanghe River was analyzed with the survey data, historical statistic data and Landsat TM images of 1987 and 2002. Following conclusions were reached: 1) Physiognomy factors at the entrance, irrigation project and integrated environment evolvement in the Weihe River basin are the main factors for channel evolution at the entrance of the Weihe River to the Huanghe River. 2) The channel evolution not only reduces the ability of controling flood in the lower reaches of the Weihe River due to shrinking of the riverbed, but also increases the flood threat in the lower reaches of the Weihe River because the Huanghe River water inversely flows into the Weihe River. And there is a complexion of small flux, high water level and big disaster, which leads to the expansion of the alkali-saline cropland in the conflux area of the two rivers. 3) The regionalism and local protection must be broken to implement the integrated planning of the watershed and to decline the height of Tongguan to stabilize the physiognomy at the estuary.