A hatch useful for forming a portal to a sub-surface facility has a cover plate with a plurality of fasteners around its perimeter. These fasteners apply an adjustable compressive force on the cover plate. A compressible material is affixed to the cover plate inward from the perimeter adjacent to the fasteners. A first vertical portion of a rectangular channel has a first end penetrating the compressive material to form a water barrier with the penetration distance being determined by the compressive force. A mechanical stop determines a maximum penetration depth.