Laguna : 汽水域研究

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Laguna : 汽水域研究 10
2003-03 発行


Characteristics of Flushed Dam Sediments with Dark Sludge from Dashidaira Dam, Toyama, Japan
Tazaki, Kazue
Kunimine, Yukie
Morikawa, Toshikazu
Khodjah Chaerun Siti
Asada, Ryuji
Miyata, Koshiro
Wakimoto, Rie
Ikeda, Yorimasa
Sato, Kazuhiro
Segawa, Hiromi
Koji, Nanae
Fujisawa, Akiko
Moriichi, Shingo
Dashidaira Dam and Unazuki Dam at Kurobe River, Toyama, Japan are regularly flushed sediments since 1991. The flushing of sediments has been impacted on ecosystem of under stream and Toyama Bay. Parameter of river water, such as pH, Eh, EC and DO at four places, were measured. Clay mineralogical components of dam sediments conducted in the two reservoirs have made it possible to evaluate the characteristics of sedimentation. Biological data are also essential because they allow comparisons to be made with conditions upper and lower of the dam sediments. At 15:30 on July 14 th, 2002, dark sludge with low oxygen was flushed from Dashidaira Dam, which was collected from Ononuma Park. The dark sludge contains expandable clay minerals with strictly anaerobic bacteria, indicating pH 6.8, Eh -210 mV, EC 143μS/cm and DO 0.9 mg/l. Physical, mineralogical and biological properties of flushed dam sediments(dark sludge) from Dashidaira Dam differ from the upper clean stream cause strong negative in downstream of Kurobe River. It had better leave river alone.