Potamological Studies on the River Ina of the River System of Yodo (I)

近年,都市河川としての重要度がますます高まりつつある猪名川について,その水質を主とした河川学的調査研究を昭和42年以来行っている。本報では水質の時間的変動について報告する。In order to promote potamological studies on the River Ina, the authors have carried out two kinds of observations, one consecutive at a few stations and another itinerant along the river. The data were collected a few days after rainfalls. In this paper, the variations of water temperature and the quality of river water at three stations which measured consecutively at every hour for twentyfour hours (10:00～tomorrow 10:00) or seven hours (10:00～17:00) were discussed as follows: Water temperature is much influenced by atmospheric conditions. pH is comparatively high at day time and rather low at night, and a day-and-night variation of 4.3 alkality is similar to pH. Very low chlorinity is observed in the case of a large quantity of precipitation, and rather small values of COD (occasionally abrupt large value) and SiO_2, and slightly large values of Ca^<2+> are measured when the precipitation is very small amount. The variations of Cl^-, COD and SiO_2 are very large and much complicated, so any one average of measured values of these costituents for twenty-four hours does not correspond to the representative of each amount. At the confluence near the Golf Bridge, the main course shows large values of pH, 4.3 alkality and Ca^<2+>, and small values of COD and SiO_2, while the tributary shows small value of 4.3 alkality, large value of SiO_2 and almost constant values of pH and ca^<2+> even when the amount of precipitation above mentioned is very large. Comparisons between seven-hour observations and twenty-four-hour ones of those components suggest that twenty-four-hour means may be estimated approximately by seven-hour means in the case of water temperature, pH and 4.3 alkality