MODELING STORM RUNOFF AND SEDIMENT WITH SEASONAL VARIATIONS

ABSTRACT An approach to simulate space and time distributed storm runoff and sediment discharge with seasonal variations of watershed characteristics is investigated. Model RUNOFF was applied to a small rural watershed in Mississippi to simulate runoff and sediment generated by storms occurring in different seasons of the year. The sensitive model parameters, which are the SCS runoff curve number and the flow detachment coefficient, were adjusted to match the predicted water and sediment discharges with the observed data. Variations of the parameters, with respect to the seasons, follow clear patterns. These patterns may be used to select parameter values, as well as simulate storm runoff and sediment, throughout a year.