Influence of time step of design storm on design drainage coefficient

Abstract

    This paper presents the assessment of influence of time interval of design storm on design drainage coefficient values of agricultural and rural areas in Hanoi region. The results show that, the effect of design storm time step on design drainage coefficient is considerable. When the time step increases, the drainage coefficient reduces, the decrease rate of drainage coefficient of rice is lower than one of others. The study built a table of value of K which is the ratio of drainage coefficients derived from hourly and daily rainfall. This result can be used to determine hourly design drainage flow of channel, culvert,...when the daily drainage coefficient is known.