Recurrence Probability of 11-Year Continuous Low Water Period (1922-1932 A. D.) In the Yellow River

1922-1932 A.D.was a continuous low water period 11 years long in the Yellow River Basin.Based on the measured data of the waterlevel scale at Qingtongxia and Wanjintan from the beginning of the eighteenth century (the Qing Dynasty) and the water regime reports to the Emperor by local officials, this paper estimates high and low water regime for the past 200 years.Combining these estimates with stochastic hydrology calculation,it is concluded that the recurrence period of the continuous low water period (1922-1932) is 200 years at least.The conclusion is rather important to recognizing year-to-year variation of the Yelleow River water resources and to development and use of the Yellow River water resources.