Abstract
When a bridge is built between two islands where the means of traffic is by a ship, the mobility is stabilized.
The construction technology of the underground dam stabilizes agriculture water. The agricultural production of neighboring island is stabilized by sending water, which storing in the underground dam, from an island to the island where it cannot be constructed. It is enabled by attaching a water pipe to the bridge built between two islands.
There is another profit in neighboring island that had been sent groundwater. Through the bridge, meals in the island will be satisfied, where been given the profit from neighboring island. It is big result by the bridging that exchange of the profit is enabled between two islands.
In this paper, we compare them to two profits of two islands, one is the fresh fish fished near the neighboring island and one is the water storing by underground dam in a certain island. And we consider to distributing those profits at the time of before and after, when is built the bridge between two islands.
Furthermore, after bridging we extend the absolutely needed quantity of profits that we can use by maintaining facilities again, one method is to build the water treatment facility for plant which can change water storing in underground dam for agriculture use and cooking, and another is to rebuild the incidental facility to cryopreserve fresh fish in a port. Finally, the synergy will occur, and the total utility of islander in two islands will be maintained in a high position.
