recess 44 and slots 50 this would normally result in loss of suction applied in the system due to the leakage in the end zones and also reduces the efficiency of the system since the air passing through openings 54 into recess 44 does not pass through the wire and web of material thereon and does not act in dewatering the material to avoid this leakage a water deckle is formed at the location of each opening 54 to seal the transverse edges and accordingly the end zones of each blade 30 this is accomplished by directing a manifold conduit 56 from a conventional water source not shown in a direction parallel to the direction of travel of the wire 22 along the drainage table at the location of each blade 30 a pair of transverse conduits 58 and 60 are directed from the manifold conduit 56 to each of the transverse edges of the blade each of the transverse conduits terminates in an opening 61 directed at the downstream open end 48 to each recess 44 of blade 30 water directed through manifold conduit 56 and transverse conduits 58 and 60 to each blade 30 preferably under high pressure will then flow in the direction of the arrows as shown in fig1 and 2 in an upstream direction at the transverse edge of the blade and form a water seal at the transverse edges closing openings 54 and preventing leakage of air at those points thus in operation material to be dewatered is placed on wire 22 and.