<p>The present invention relates to a seawater communication hole preventing a leakage of dredging soil while minimizing a water head difference of the sea surface and a hinterland. The present invention comprises: a seawater pipe (100) which is installed to penetrate a revetment (10) forming a boundary of a waterfront landfill planned place to enable one end to head toward the outside of the revetment (10) and to enable the other end to head toward the inside of the revetment (10) to be penetrated from one end to the other end to enable seawater to be communicated; and a seawater pipe flap gate (200) which is provided to the other end of the seawater pipe (100) to be opened by seawater introduced from the outside of the revetment (10) through the seawater pipe (100) to allow introduction of seawater and closes the seawater pipe (100) with seawater discharged from the inside of the revetment (10) to prevent the leakage of seawater.</p>
