Floating docks are buoyant platforms supported by pontoons, also known as vertical poles, which are anchored to the river bed. For better support, larger floating docks sometimes boast a ramp, either fixed or mounted on rollers, that rests on shore.
Frequently used in private docks and marinas, swimming areas, and landing piers, floating docks can be constructed from a variety of materials, including lumber and Styrofoam/polyethylene combinations, modular aluminum, stainless steel, and galvanized steel. Some companies are experimenting with alternative materials, such as plastics, concrete, and fiberglass, but wood remains the material of choice because it's relatively inexpensive and easier to install and maintain. Anti-slip paint finishes and handrails can be added for increased safety, and many companies are now offering floating docks in a variety of colors and finishes to fit any style and decoration. In waters that freeze during winter, floating docks can easily be removed to avoid structural damage.
Floating docks are self-leveling, which means they can adjust to water-depth fluctuations, making them perfect for both coastline and open-water settings. They are also great for waters deeper than eight feet and soft river bottoms that cannot hold permanent structures in place, since floating docks offer many choices for anchoring, including cables, ramps, and mobile pipes, and can be tailored to the environmental conditions of the area. Floating docks have only one major problem: they can bounce around and become unstable on strong-moving waters, so they are not recommended in areas where high waves are common. They also need a water depth minimum of three feet in order to have sufficient draft to actually float.
Because of the possible impact on marine life and shoreline ecosystems, all docks require a construction permit issued by both local agencies and the fish and wildlife department. In especially fragile areas, a permit for floating docks can easily run into the thousands of dollars. Once a permit is obtained, floating docks can be put together from a pre-made kit for about $14 per square foot. To get an idea of the total price, it's important to keep in mind that floating docks should be a minimum of 6 by 20 feet (1.8 by 6.1 meters) to guarantee stability. A certified dock builder can help you deal with all necessary paperwork and ensure a safe construction, but you should keep in mind the added cost, which can be up to twice the price of the do-it-yourself kind.