Effects of rainfall and runoff-yield conditions on runoff

To reveal the effects of rainfall and runoff-yield conditions on runoff, the abrupt change of the correlation between rainfall and runoff is discussed. Then, according to the correlation between rainfall and runoff with the different rainfall states, the multivariate dynamic regression models of rainfall and runoff are constructed, and the effects of rainfall and runoff-yield conditions on runoff are analyzed. The results show that (1) the correlation between rainfall and runoff changed abruptly in 1980; (2) the rainfall changes lead to runoff reductions, and runoff decreased by 15.79% under the runoff-yield conditionl from 1959 to 1979, while it decreased by 8% under the runoff-yield condition II from 1980 to 2013; (3) the change of the runoff-yield conditions lead to the runoff reduction of 41.16% from 1959 to 1979, while it leads to a decrease in runoff by 35.58% from 1980 to 2013. (C) 2020 The Authors. Published by Elsevier B.V. on behalf of Faculty of Engineering, Ain Shams University.