In the plantation period, shallow wells, supplemented by rainwater collected in cisterns, provided sufficient water for the pastoral lifestyle of the small population. On Diego Garcia today, the military base uses over 100 shallow "horizontal" wells to produce over 560,000 L per day from the "Cantonment" lens on the northwest arm of the island—sufficient water for western-style usage for a population of 3,500. This 3.7 km2 lens holds an estimated 19 million m3 of fresh water and has an average daily recharge from rainfall over 10,000 m3, of which 40% remains in the lens and 60% is lost through evapotranspiration.