Mechanizum analysis of water purification in wetlands in Monsoon Asia

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K12413
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 64040:Social-ecological systems-related
• Research Institution: Gifu University
• Principal Investigator: Noda Keigo 岐阜大学, 応用生物科学部, 准教授 (60646371)
• Co-Investigator(Kenkyū-buntansha): 木村 匡臣 近畿大学, 農学部, 講師 (80725664)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: 水環境 / 湿地 / 水質浄化 / 生態系サービス / 農地

Outline of Final Research Achievements

In this study, water quality was observed in urban rivers, natural rivers, and irrigation drainage networks in order to elucidate the mechanism of water purification function of wetlands in Monsoon Asia. The results showed that EC value of urban rivers and irrigation drainage area was about the same in the rainy season, but in the dry season, EC of urban rivers was about two times higher than that of irrigation drainage area. Urban rivers in Laos receive both domestic wastewater and rainwater runoff, which is thought to dilute the water quality load to about twice as much during the rainy season as during the dry season. On the other hand, EC of wastewater from irrigated drainage areas was almost constant with small fluctuations throughout the year. This may be due to the dilution effect of drainage from rice paddies during the dry season.

Free Research Field

農業水利学

Academic Significance and Societal Importance of the Research Achievements

（学術的意義）本研究では，都市部から排出される汚濁負荷と農村部から供給される希釈水を考慮し、その湿地域の水質浄化機能への影響を明示的に評価した．特に，そのメカニズムがモンスーンアジアの特徴である雨季と乾季によって大きく異なることを示した．これは，従来の水質浄化機能の「固有の許容量」という考え方とは異なる新しい知見である．
（社会的意義）この成果に基づき，水質悪化が顕著な乾季に焦点を当てた「乾季環境用水量」の必要性と灌漑地区の排水がその供給源となりうることが示された．