2000 Fiscal Year Final Research Report Summary
WATER QUALITY RESTORATION IN LAKES AND RESERVOIRS USING NATURAL ENERGY
| Project/Area Number |
11450189
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| Research Category |
Grant-in-Aid for Scientific Research (B).
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
水工水理学
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| Research Institution | KYUSHU UNIVERSITY |
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Principal Investigator |
KOMATSU Toshimitsu Faculty of Eng., Prof., 大学院・工学研究院, 教授 (50091343)
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| Co-Investigator(Kenkyū-buntansha) |
INOUE Tetsunori Faculty of Eng., KYUSHU UNIVERSITY, Res.Ass., 大学院・工学研究院, 助手 (70311850)
OSHIKAWA Hideo Faculty of Eng., KYUSHU UNIVERSITY, Res.Ass., 大学院・工学研究院, 助手 (80311851)
ADACHI Takahiro Faculty of Eng., KYUSHU UNIVERSITY, Ass.Prof., 大学院・工学研究院, 助教授 (50325502)
HASHIDA Misao Nippon Bunri Univ., Faculty of Eng., Prof., 工学部, 教授 (70131969)
NAKAMURA Takehiro Nagasaki Univ., Faculty of Environ.Eng., Prof., 環境科学部, 教授 (70039692)
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| Project Period (FY) |
1999 – 2000
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| Keywords | water quality restoration / surface water injection / reservoir / dissolved oxygen / nutrient release / water temperature stratification |
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| Research Abstract |
Dissolved oxygen (DO) depletion, which is usually observed in eutrophic lakes and reservoirs, damages natural benthic organisms and enhances nutrient release from the sediment. As a countermeasure aganist these problems, a method which injects surface water including a large amount of DO into the bottom layer, in which DO is often depleted, was proposed. In this study, the water quality restoration in case of continuous or intermittently injection of surface water into hypolimnion was investigated by field experiments performed in an enclosure system which is 100m^2 in area, and in a reservoir which is 15000m^2 in area and 5m in maximum depth. Furthermore, the effect of this system on sediment quality restoration was also investigated by a laboratory experiment.
Field experimental results revealed that this system suppressed nutrient and dissolved metals release from the sediment even when DO was depleted by sediment oxygen demand (SOD). Laboratory experimental results also revealed that SOD measured after the procedure had smaller values than those measured before the procedure. This might be due to the continuous DO consumption of organinc materials in the sediment during summer in 2000, promoted by continuous injection of surface water. The experimental and observational results indicate that this system is a promising method to restore water and sediment qualities in enclosed water areas.
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