Japanese Journal of Water Treatment Biology
Online ISSN : 1881-0438
Print ISSN : 0910-6758
ISSN-L : 0910-6758
Organic Water Pollution of Tatsumi Watercourse and Ichinose Irrigation Canal in Ishikawa Prefecture
Michiaki SUMITAToshiharu WATANABE
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1988 Volume 24 Issue 1 Pages 103-113


Both Tatusmi Watercourse and Ichinose Irrigation Canal run through populous areas in Ishikawa Prefecture.
Investigations were done in August and November, 1985 in Tatsumi Watercourse and in July, 1985 in Ichinose Irrigation Canal. In this study three different kinds of values were obtained at each of the six stations in both watercourses: the values of physical and chemical characteristics of water quality, those of DAIpo (Diatom Assemblage Index to organic water pollution) and those of RPID (River Pollution Index) .
In Tatsumi Watercourse the water quality becomes slightly polluted in the downstream, but the values of DAIpo show that it remains clean on the whole. In the main stream the values of RPIDwere 66 in August, 78 in November. They were 71 in August, 77 in November in the watercourse to Kenrokuen Park.
In Ichinose Irrigation Canal, the values of DAIpo showed a low values of 26 at station 3. This is caused by the inflow of a great deal of domestic water from the urban area of Yamashiro Spa. But the values of DAIpo of the downstream stations showed higher values, which means the water becomes cleaner as it leaves the urban area.
Numerical assessment chart and the values of RPIDshowed that obviously the different quality of the water pollution between these two watercourses. It was caused by the fact that the Ichinose course does not have a sewage system.
The main points at issues to be examined relating this study are as follows: 1) In Tatsumi Water course measures are needed by which constant flow rate of water is to be secured throughout the year.2) In Ichinose Irrigation Canal the inflow of polluted water to Lake Sibayama-gata should be avoided. So it is necessary to establish a sewage system in the urban area of Yamashiro Spa.

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