Study on the river regime of the parallel three rivers in longitudinal gorge region of Northwestern Yunnan Province

The studies of the river regime have been put great emphasis on the river research.In this work it is analyzed the characteristics of annual suspended sediment load,annual water runoff and annual change of cross-section in selected four hydrological gauging stations of the parallel three rivers of the longitudinal range gorge region in the Northwestern Yunnan Province.The data were measured annually from 1955 to 1987.The trend of annual river regime,hydraulic geometry indexes of the three rivers has been obtained using the Loepold and Moddock's experiential equation.The experiential equation of Loepold and Moddock is having more extensive application,not only for alluvial rivers,but for non-fluvial rivers of the mountainous area.Its hydraulic geometry indexes could reflect the narrow and deep features of the mountain rivers.Further more,the studies on changes of the hydraulic geometry indexes show that the indexes are controlled by the channel cross-section determined at the peak-floods.The study has focused on the expansion of the river regime theory and provides a scientific basis to the comprehensive rectification vertical of the parallel three rivers of the longitudinal range gorge region in the Northwestern Yunnan Province.