This is a natural occurring floating peat bog in Northern Wisconsin, USA. It is a floating islands, also called sudds, tussocks, floatons, or embalsados, typically composed of floating vegetation, or peat, or both, along with mud, and may attain substantial thickness and longevity, sustain abundant riparian vegetation, and provide habitat for high densities of fish. As the water gets deeper the roots no longer reach the floor, so these floating islands made of vegetation use the oxygen in their root mass for buoyancy, and the surrounding vegetation for support to retain their top-side-up orientation.
You're telling me, you can't put stakes and ropes/chains to anchor it at a specific part of land? It has to be touching land somewhere anyways. It cannot just float indefinitely; so why not just attach it to the best spot, that's good for the wildlife, that it wont come loose at?