SEAWATER INFILTRATION INTAKE DEVICE

PROBLEM TO BE SOLVED: To improve the cleaning effect of a sand filter layer and to keep infiltration of seawater at high rate.SOLUTION: A seawater infiltration intake device 11 is provided with: an intake pipe 12 which takes in seawater infiltrating through a sand filter layer 31 from a sea; and a cleaning pipe 13 which cleans suspension materials S causing clog of the sand filter layer 31 by jetting air into the sand filter layer 31. A baffle plate 14 having an opening 14a is arranged above the sand filter layer 31. A filtering surface cleaning effect is obtained even when seawater is taken, by generating a shear flow on the surface of the sand filter layer in a direction crossing the infiltration direction of seawater when seawater is taken. Moreover, when the sand filter layer is cleaned, the suspension materials rolled up above the sand filter layer is captured and discharged out of the system through the opening along with the air jetted from the cleaning pipe.