@article{oai:u-ryukyu.repo.nii.ac.jp:02007064,
 author = {渡久山, 章 and 下地, 寛 and Tokuyama, Akira and Shimozi, Hiroshi},
 issue = {26},
 journal = {琉球大学理工学部紀要. 理学編, Bulletin of Science & Engineering Division, University of Ryukyus. Mathematics & natural sciences},
 month = {Sep},
 note = {What are the natural states in OKINAWA HONTŌ? A part of the authors' purposes is to get knowledge about them, which may be achieved by knowing the chemical composition of river water and considering the origin of dissolved chemical species. The region where the natural states are preserved best in the OKINAWA HONTŌ is the northern side. We collected sixty four water samples from the rivers scattered around the north region of NAGO. Samples were collected from 3rd to 6th of May in 1977. The following results were obtained. (1) The total concentration of dissolved chemical species on an average is 120 to 130 ppm at normal flux. (2) Sixty per cent of these may be supplied from the land. (3) The per cent of alkalinity, SiO_2, Ca^<2+>, Mg^<2+>, K^+, So^<2->_4 and Na^+ which might be supplied from the land are calculated to be 100, 100, 94, 50, 50, 50 and 20 respectively. (4) The maximum quantity dissolved from the OKINAWA HONTŌ were estimated to be less than 3.6 hundred thousound tons per year. (5) The chloride ions concentration was reduced with increasing the distance from the sea. (6) When rock and soil contact with water, the behavior of dissolved chemical species was complex. For example, the relationship between excess Ca^<2+> +Mg^<2+> and alkalinity was linear but SiO_2 had no any relationship with other species. (7) The river waters which originate in NISHIME DAKE, TERUKUBI YAMA, YONAHA DAKE and IYU DAKE are the softest and the effect of sea water on them is the least in OKINAWA HONTŌ. The flux of these rivers is large compared to the other rivers of OKINAWA HONTŌ., 紀要論文},
 pages = {31--52},
 title = {沖縄本島北部河川水の化学的研究及び流出量},
 year = {1978}
}