Development of Cloud Water Resources over the Upstream of Yangtze River to Increase Water Amount of the Middle Route of South-to-North Water Transfer Project

Due to climate change and over developing,wetland sharply decreased and ecological deteriorated over the headstream of Yellow River,Yangtze River,Lancangjiang River and upstream of the Hanjiang River,which resulted in an abrupt change from more to less runoff in 1991 for Danjiangkou Reservoir,so the water resources of Danjiangkou can not meet the need of the first-stage of the middle route of South-to-North Water Transfer Project.So developing the rich cloud water resources over upper reaches of Yangtze river is important to solve the water shortage of middle-route of the South-to-North Water Transfer Project.The water vapor is abundant over the Yangtze River basin,the annual input of water vapor approximates 67 800×108 m3,in which only 28.5% turns into precipitation.If we carry out artificial rain enhancement operation in the upper reaches of the Hanjiang River,the Danjiangkou reservoir runoff could increase 17.5×108 m3,so the actual water adjustable will amount to 90.2×108 m3,but it is still less than 128×108 m3 water we needed in 2030.If the percent efficiency(Pe) of precipitation is 30%,enhancing efficiency(EW) is 10% by conservative estimates,the annual total rainfall would increase 162.1×108 m3 and 23.7×108 m3 in the two regions,respectively,and Three Gorges reservoir and Danjiangkou reservoir inflow runoff would increase 83×108 m3 and 11.6×108 m3,respectively,which is together with the original water would meet the water need of 2030.