Abstract: An apparatus is disclosed for containment of contaminants during an underwater dredging operation. The apparatus includes an elongated anchor which is adapted to lie on a water bed. A flexible sheet which is substantially impervious to silt has a bottom edge secured to the anchor. A float is secured to the top edge of the sheet so that the sheet forms a dam and prevents contaminated silt from passing from one side of the sheet to the other. In practice, a plurality of these sheets and anchors are disposed around and enclose a contaminated area thus maintaining silt within the interior of the enclosed area.