Abstract
Because of the geographical nature, water source is difficult to develop in islands. So water shortage is serious in island area. Relatively vulnerable to natural disasters, in emergency they have to rely on water supply ship. But water supply ship is not enough and the distance to island is far, island's water supply system is unstable and poor. In addition, most islands rely on a single water source, in the event of a disaster Island residents face serious water shortages. Thus, a stable water supply on the island in order to come up with measures to increase the absolute amount and the administration should seek to increase the supply effect. Also, in an emergency to minimize the social and economic damage and supply standard precautions should be made. In this study, Shortage of water supply on the island that can lead to a scenario was created and then estimating water deficit and to assess the vulnerability of water supply was. Water shortage crisis that can cause in island area were classified. Also water deficit was estimated when each water supply was interrupted and other water sources can not substitute. And vulnerability was assessed by possibility of cause damage to the water supply.