Vertical Transport Process between Sediments and the Upper Water Column With Changing Water Pressure

• Published in: ENVIRONMENTAL ENGINEERING RESEARCH Vol. 45; pp. 525 - 533
• Main Authors: Tuchiya Daisuke, Kusuda Tetsuya, Hamada Kouji
• Format: Journal Article
• Language: Japanese
• Published: Japan Society of Civil Engineers 2008; 公益社団法人 土木学会
• Subjects: Ariake bey; sediment; tide; water transport
• ISSN: 1341-5115; 1884-829X
• DOI: 10.11532/proes1992.45.525

this study, we investigated a method to strengthen water transport between the sediment and the upper water column in a bay, which is induced by ebb and flood tides as a sediment characteristics improvement technique. For using this model, it turned out that the device, an air holder, newly developed to hold air in sediments. Effect of the device was identified by laboratory experiments under varying water pressure at the same level as ebb and flood tides. The simulation model which is estimated a method is able to estimate the effect on water transport with the device. A compared result of laboratory experiments with simulated results, this model is applicable and the device is useful. Several pieces of the device were laid in the sediments at Ivfiike muddy tidal flat in Omuta City, Fukuoka, Japan. Biological effects were identified by measuring mad flat's oxidation-reduction potential (ORP), that is, the sediments turned aerobic. 本研究では, 潮汐作用を水質改善手法に利用するために堆積物一直上水間の輸送量の増加方法を検討した. まず, 潮汐と同程度の水圧を堆積物にかける室内実験にて, 人工的に気泡を増加させる手法が効果を発揮することを確認した. そして, 自然状態における海水の鉛直輸送量を予測するモデルを元に, 本手法の効果を推定するモデルを製作した, シミュレーション結果と室内実験の結果とを比較し, モデルの妥当性を確認し, 合わせて, 本手法による輸送量増加の効果が実際に存在することを確認した. これらを踏まえ, 大牟田市地先三池港干潟において現地実験を行い, 長期間, 気体保持装置が機能することを確認し, 干潟の底質改善に効果があることを明らかにした.