東北地方における2・3の灌漑水路水温の実態について (II)
1963 年 15 巻 4 号 p. 136-140
詳細
1963 年 15 巻 4 号 p. 136-140
The temperature of irrigation water is one of the most important factors which influence the productivity of rice-field in Northeast Japan. Lately, some experimental or theoretical studies on it have been carried out, but observations in field are very few. Following the previous paper1), this is a report on the water temperatures of some irrigation water-ways at the foot of Mt. Bandai and in the Yonezawa Basin. Observation was made on July 12th, 16th and 17th, 1955. The following are pointed out through the observations in the four districts.
1. There are marked differences of water temperature in the water-ways. Such are due to the difference of their sources, whether it is mountain torrent, long trunk water-way, spring at an end of alluvial fan, or river and storage dam.
2. From the rising rate of water temperature (the value raised per 1 km of flow), it seems that the ground water and the earth temperature along water-way are the important factors that influence water temperature, together with air temperature and isolation. Most of water-ways are open ditches without concreat walls and bottoms, and therefore the above-mentioned factors are closely related to the depth of water-ways and the surface landforms through which the water-ways run.
