Abstract
Characteristic of COD in Rikimaru Reservoir in Fukuoka Prefecture was surveyed from April 1986 to February 1988, in oder to study applicability for trophic state index of TCOD and obtain the optimum sampling sites. The results were as follows :
(1) TCOD represented well the standing crop of algae at each sampling site. This tendency was recognized more clearly at St. 1 (damsite).
(2) DCOD results from the metabolic matter of algae was much higher than that of the previous reports.
(3) DCOD correlated with the standing crop of algae at St. 1 and St. 5 (sub-inlet of reservoir).
(4) CCOD calculated from the slope of the regression line between Chla and TCOD was seemed to contain DCOD results from the metabolic matter of algae.
(5) St. 1 was the optimum sampling site of reservoir dam up river.
