抄録
In the period of the water shortage during summer, the fluctuation characteristics of water quality in river is different from those of the other seasons. This is due to the fact that the solar radiation is so strong in this period that water temperature rises gradually and reaches 25-26°C.
In this study, the changes in the discharge, the velocity of flow, the quantity of solar radiation and the water temperature during this period of the water shortage are investigated and at the same time, the changes in the concentration of Chl-a, COD, SS, PO4-P, and NO3-N are investigated. As the results of the two investigations of 1981 and 1984, it is known that the Chl-a concentration increases suddenly as the discharge decreases and that the concentration of NO3-N and PO4 -P decreases gradually with the increase of the Chl-a concentration. It is also known that the Chl-a load in this period is influenced greatly by the cumulative product of the values of the water temperature and the quantity of the solar radiation of the previous three days.
