Water harvesting ensures that a greater percentage of rainfall is put to a beneficial use by concentrating water on productive areas. Water storage conserves surplus water in the rainy season, when rainfall exceeds demand, and allows prolongation of the cropping period into the dry season. The water stored may also cover the demand of crops in dry spells during the rainy season. Generally, there are two means for storing harvested water:

Direct storage in the soil profile, which is usually associated with runoff farming. Water storage in tanks, cisterns, ponds, or reservoirs. A storage facility is often required for water distribution supply systems in areas

with long dry periods. Where precipitation fluctuates widely over years, storage of harvested water outside the soil matrix becomes an essential part of the water harvesting system.