I'm planing a 20,000 sq/ft pond. We have sandy loam soil so I bought a RPE liner to use. In the spring, the water table is at at ground level and stays high for 3-4 weeks. I'm worried the liner is going to bubble from hydrostatic pressure.

If I create a berm around the whole pond about 1ft higher than the spring high water mark, will this create enough down pressure to keep the liner from bubbling?

Is there another way to keep the liner down?

Thanks