ESTIMATION OF MASS FLOW IN THE YAMATOGAWA BASIN

Daily mass flow values of COD, Cl-, T-P and NO3-; in the Yamatogawa basin could be calculated from daily flow rates because the mass flow values were proportionate to flow rate. Though flow rate was measured daily, the concentrations were measured once a month. Daily mass flow values of BOD and NH4+ could not be estimated from daily flow rate however because the mass flow values of BOD and NH4+ didn't depend on flow rate but rather on water temperature. The calculated daily mass flow value of COD per number of people was high in the high density population area. The values of Cl-, and NO3-per number of people were low but abnormally high in the high density population area. The values of T-P per the number of people and per area were high in the farmland area and low in both the forest area and the housing site. The values of COD, Cl-, and NO3- per area were high in the housing site.