Ceterns, some of them dating from Moorish times, catch whatever rain falls from the sky, and when needed, supplementary water supplies are shipped in to this desert island.
Ceterns provide all of the needed water in winter.
mnli hypothesis: Ceterns provide all of the needed water in winter. premise: Ceterns, some of them dating from Moorish times, catch whatever rain falls from the sky, and when needed, supplementary water supplies are shipped in to this desert island.