Abstract
Pollutant loadings in dry and wet weathers are observed at Tokiwa and Daini drainage areas that are residential districts. They are 21.3 ha and 1900 inhabitants, 90 ha and 8500 inhabitants, respectively.
The characteristics of pollutant flux are affected by rainfall and rainfall intensity. It is indicated in this study that annual pollutant loadings could be estimated using these equations.
For BOD, D-CODMn, TN, D-TN, TP, D-TP
L=365·LD+R1·f1·C1/100+R2·f2·C2/100
For SS, CODMn
L=365·LD+R1·f1·C1/100+Σa·10b·Rpn/A
L: Annual pollutant loading (kg/ha·y)
LD: Pollutant loading in dry weather day (kg/ha·d)
R1, R2: Yearly accumulated rainfall for less than 20mm rainfall and for more than 21mm rainfall, respectively (mm/y)
f1, f2: Average rate of runoff for less than 20 mm rainfall and for more than 21mm rainfall, respectively
C1, C2: Average water quality for less than 20 mm rainfall and for more than 21mm rainfall, respectively (mg/l)
Rpn: Peak rainfall intensity in nth rain of more than 21mm rainfall (mm/hr)
A: Drainage area (ha), a, b: Constant
