Abstract
The flow rate and the water quality in urban small rivers show diurnal variations which are caused by human activity in catchment areas.
In this paper, detailed data on the diurnal variation in the Hikiji River are presented. The catchment area of the river is well urbanized, but sewage treatment facilities are not completed.
A simple transport model based on unsteady flow caluculation is presented in order to relate the diurnal variation of the river flow to the discharge from residential areas which do not have sewage treatment facilities. The model successfully reprodu ces hourly variations of the flow rate, the DOD5 concentration and the NH4+ concentration.
