Maintenance Free Floating Covers
Floating covers are a very economical method of protecting precious water. The cost can be 20% of that for other cover options. Industry-recognized guidelines exist for the design, installation and maintenance of floating cover systems. An example is the American Waterworks Association (AWWA) standard D130-87, which contains the most current standard practices observed for system compliance to US national health and safety regulations.
The California-Nevada Section American Water Works Reservoir Floating Cover Guidelines dated March 1999 offers an excellent source of design, operations and maintenance guidelines.
Floating Covers are customized for each client’s lagoon or tank size and shape. A series of lateral floats provide pathways for gas to flow underneath to the perimeter collection pipe and on to a single collection point. The lateral floats keep the entire cover floating on the waters’ surface, and eliminate cover inflation, and exposure to wind damage.
Floating covers that inflate (without lateral floats) expose the geomembrane cover to vibration and geomembrane fatigue from wind constantly blowing over the inflated cover. This significantly reduces the life span of the cover. Ballast weights on top of the floating cover channel rainwater and snow melt to sumps to remove all rainwater from the surface of the floating cover.
Properly designed reservoir-floating cover systems prevent fluid loss due to evaporation, reduce chemical demand and improve water quality by preventing contamination from bird droppings, airborne particulates, dead animals, pollen and other pollutants. Floating covers block off sunlight preventing algae bloom. They also reduce the production of trialomethane (THM) type compounds such as chloroform from forming that result from the combining of organic substances with chlorine due to reductions in chlorine demand.
Floating cover systems were introduced over 30 years ago. Many have provided a service life beyond 20 years. When first introduced, materials and designs were not developed and in some cases had limited success. Today, with advancements in design and materials, floating covers offer the low cost quality solution of choice where water quality standards require potable water reservoirs be covered.
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