地下水が遮断された河口干潟でのアサリ育成場の構築  [in Japanese] CONSTRUCTION OF THE SHORT-NECKED CLAM FISHERY GROUNDS IN THE ESTUARY TIDAL FLATS WHERE GROUNDWATER WAS STOPPED  [in Japanese]

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Abstract

広島デルタ河口域に形成された河川干潟では,ヘドロ化が進みアナジャコ等が優占する泥干潟になり,アサリ漁獲量は種苗放流の効果も少なく激減している.また,河川護岸の防災機能強化を目的とした護岸法尻への鋼矢板の打設により,護岸堤内側から河川干潟の地下に流出していた地下水が遮断され,干潟環境が変化していると想定される.<br> 泥化が進行し地下水が遮断された河川干潟内の澪筋において,石炭灰造粒物を0.3m厚の覆砂状に敷設することによるアサリ育成場の構築を試みた.造粒物の散布により造粒物層および散布境界部での生物相が変化し多様な生物の生息環境が形成されつつある.造粒物散布12ヶ月後には定着したアサリの生息が確認され,石炭灰造粒物による覆砂によりアサリの生息が可能な環境を創出できる可能性が確認された.

 The catches of the short-necked clam decrease for sedimentation of the sludge remarkably in the estuary tidal flats of the Hiroshima delta. On the other hand, a steel sheet pile is set up for revetment to prepare for a disaster. The groundwater which flow out underground of the tidal flats was stopped at the landside by a steel sheet pile. And it is assumed that the environment of the tidal flats changes.<br> The fishery grounds of the short-necked clam spread a granulated coal ash (GCA) on thickness of 0.3m in the ebb water route of the tidal flats and built it. By laying of the GCA, the biota is turning into the environment where various creatures inhabit. 12 months after laying of the GCA, the habitation of the short-necked clam was confirmed. It was confirmed that the overlaying sand of the GCA might build the environment where the habitation of the short-necked clam was possible.

Journal

  • Journal of Japan Society of Civil Engineers, Ser. B3 (Ocean Engineering)

    Journal of Japan Society of Civil Engineers, Ser. B3 (Ocean Engineering) 69(2), I_1024-I_1029, 2013

    Japan Society of Civil Engineers

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