A pond liner is an impermeable geomembrane used for retention of liquids, including the lining of reservoirs, retention basins, hazardous and nonhazardous surface impoundments, garden ponds and artificial streams in parks and gardens.Pond liners need to be protected from sharp objects (for example, stones) below the liner and from being punctured by any objects in the water body. Protection can be provided with layers of sand, geotextiles (particularly needle-punched nonwovens) and other materials. Pond liners are manufactured in rolls or accordion-folded on pallets. When deployed in the field their edges and ends are overlapped and seamed together. Methods are thermal fusion, solvents, adhesives and tapes.