SUPPRESSING THE EFFECTS OF ANOXIC WATER IN AN INNER BAY BY PLACEMENT OF WATER FLOW PIPES THROUGH A BAYMOUTH BREAKWATER
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- KOZAWA Keiji
- 国土交通省 東北地方整備局 釜石港湾事務所
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- MURAKAMI Kazuo
- 一般社団法人水底質浄化技術協会
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- NAKAMURA Yoshiyuki
- 横浜国立大学 大学院都市イノベーション研究院
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- ABE Ikuo
- 常葉大学 社会環境学部
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- OKADA Tomonari
- 国土技術政策総合研究所 沿岸海洋・防災研究部
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- OGASAWARA Toshinori
- 岩手大学 理工学部システム創成工学科
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- TAKAO Toshiyuki
- 株式会社エコー技術本部沿岸環境部
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- SHIBAKI Hidenori
- 株式会社エコー技術本部
Bibliographic Information
- Other Title
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- 湾口防波堤海底部の通水管による貧酸素化の抑制効果
- ワンコウ ボウハテイ カイテイブ ノ ツウスイカン ニ ヨル ヒンサンソカ ノ ヨクセイ コウカ
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Description
As part of restoration of the breakwater at the entrance of Ofunato Bay, which was damaged by the 2011 Tohoku Earthquake Tsunami, flow pipes with a diameter of 3.5m were placed through the bottom of the breakwater to enhance water exchange between the inner and outer bay. The aim of this research is to understand the effect of these pipes on the occurrence of low oxygen water based on field experiments conducted after the completion of the breakwater. These field experiments indicate that the main effect on water exchange due to the flow pipes was the discharge of low temperature, high density water masses inside the breakwater to the outside of the breakwater, with flow speeds in the pipes sufficient to discharge the entire volume below the top mound of the breakwater (-16 m depth) in about 10 days. The effect of this enhanced exchange was to allow easy intrusion of low temperature water masses that appeared in the outer bay into the lower layer of inner bay. Since the temperature inside the mounds had been increasing, the cold water intrusion prevented the inner part of bay developing a persistent low oxygen environment.
Journal
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- Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering)
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Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering) 73 (2), I_469-I_474, 2017
Japan Society of Civil Engineers