Other methods used for waste storage include above or below ground tanks of concrete or steel. Generally these types of storage pits have little opportunity to affect water quality. Lagoons hold diluted waste for 6 to 24 months. They are designed to allow waste to partially decompose before field application. Smaller than lagoons, earthen pits store liquid manure from one to six months.
Little decomposition occurs because of the short holding time and little dilution.
Consequently, nutrient levels are higher in earthen pits than lagoons. The bottom seal minimizes most downward nutrient leaching. The bottom of earthen basins should be lined with compacted bentonite clay or synthetic lagoon lining materials to control leaching. Earthen basins should also be lined on the inside walls to prevent leaching through the wall when the liquid level changes. Otherwise, the soil on the walls can dry and crack as the level drops.