Abstract: A floating cover assembly encompassing in a first condition a method and apparatus for tensioning a floating cover for a liquid storage reservoir wherein the surface level of the stored liquid varies and in a second condition, a method and apparatus for maintaining a liquid storage reservoir. In the apparatus of the above inventions, a peripheral envelope formed at least adjacent a portion of the peripheral edges of the floatable sheet is adapted to be inflated with a compressible fluid, such as air, for proper tensioning of the sheet as the level of the stored liquid varies in the reservoir and for preventing wrinkling of the sheet while, in the second condition, the peripheral envelop is adapted to be filled with a non-compressible fluid for providing a ballast for the sheet during maintenance operations thereof while the sheet is inflatably supported for maintenance of the sheet and/or reservoir.

Abstract: A floating cover assembly encompassing in a first condition a method and apparatus for tensioning a floating cover for a liquid storage reservoir wherein the surface level of the stored liquid varies and in a second condition, a method and apparatus for maintaining a liquid storage reservoir. In the apparatus of the above inventions, a peripheral envelope formed at least adjacent a portion of the peripheral edges of the floatable sheet is adapted to be inflated with a compressible fluid, such as air, for proper tensioning of the sheet as the level of the stored liquid varies in the reservoir and for preventing wrinkling of the sheet while, in the second condition, the peripheral envelope is adapted to be filled with a non-compressible fluid for providing a ballast for the sheet during maintenance operations thereof while the sheet is inflatably supported for maintenance of the sheet and/or reservoir.

Abstract: A floating cover for a liquid storage reservoir to prevent contamination of the stored liquid. The cover includes a continuous sheet of flexible material overlying the liquid and attached to the upper periphery of the reservoir, the area of the sheet being greater than the area encompassed by the upper periphery of the reservoir. The cover further includes floats in the central portion to float it higher than the peripheral portion whereby the excess material in the peripheral portion forms a depending rainwater collection sump..Iaddend.