Frost heave affects unlined ponds or basins by lifting and shifting the soil as water within the ground freezes and expands. Once temperatures rise and the soil thaws, it settles unevenly. This repeated movement distorts the pond bottom and walls, creating gaps, fractures, or pockets where water can escape.
In an unlined system, the soil itself serves as the only barrier holding liquids in place, so even small shifts can open pathways for leaks and seepage. Even in an empty pond, frost heave can gradually stretch or weaken the structure, making it less stable and more prone to leaks once the pond fills in the spring. These changes may not be visible from the surface, which means significant nutrient loss can occur long before problems are detected.
