Abstract: A float retaining cover device 10 comprising a non-permeable cover sheet 12 supported by a floating member 14. The latter can be a free-floating retention method using grommets 20 attached to the central underside of the cover sheet 12 and on the float 14 with a cord 22 fastening the two together, or a system using straps and fasteners. An enclosed retaining pocket 16 can also be employed to maintain the float 14. When a permeable sheet is used to form the retaining pocket 16, there is a sealable recess 40 in the sheet of the pocket 16 to insert and remove the float 14. When the retaining pocket 16 is non-permeable, all edges are hermetically sealed to the bottom of the cover sheet 12 and the recess 24 is located on the cover sheet 12 in a central position in relation to the retaining pocket 16. The recess 24 has an elastomeric border 26 that allows the float 14 to pass through when there is excessive pressure pushing down on the cover sheet.