Abstract
COD was previously measured from sampled water. Then 1 month measurement does not include flood condition because of safety for sampling. 1 hour measurement is automatically sampled and measured in situ at station and then includes flood condition. To clarify difference between 1 month measurement and 1 hour measurement, using both measuring results of flow rate, COD, TB and EC values of the Yamatogawa river, effect of flow rate on COD, TB and EC values was clarified. COD and TB values increased with flow rate. EC value decreased as flow rate increased. The relationships between COD and flow rate, TB and flow rate were very similar. Therefore, COD was more strongly influenced by floating material than soluble substances because TB was concentration of floating material. Using the relationships between COD and flow rate, COD loads were calculated. As a result, the COD load calculated by the 1 hour measurement was more about 2 times than the COD load calculated by the 1 month measurement.
