Progradation of the Yellow (Huanghe) River delta in response to the implementation of a basin-scale water regulation program
The water and sediment supply to the lower reach and estuary of the Yellow (Huanghe) River have been altered to a very significant degree by the construction of numerous small to large reservoirs and the progressive implementation of water and soil conservation measures across the entire drainage basin since the late 1950s, followed by a basin-scale water regulation program since 2002. There is an urgent need to know how progradation of the Yellow River delta (YRD), an area on which people live and farm, has continued and will continue to respond to these controls. This study examines the changing patterns of water and sediment supply to the YRD over the period of 1950-2013 and, using remote sensing, it evaluates the morphological changes of the delta during 1976-2013. Although both water and sediment input to the delta have been described as declining significantly since the mid 1960s, we show that since 2005 the supply of water has remained at around 20 billion m3 yr− 1 and that for sediment at about 0.13 billion t yr− 1; water input has been even slightly increasing. The dynamics of extension/shrinking and avulsion in river-mouth channels and accretion/erosion of shorelines is an integrated response to the complex variations in both sediment and water supply. This study develops a quantitative relationship between water and sediment supply and the area of land accretion and it predicts the critical condition for land accretion in the YRD. To ensure that delta land will not be lost, care is needed in the future implementation of the basin-scale water regulation program.