A Mathematical Model for the Capacity Expansion Problem of Inter-regional Water Supply Facilities

Abstract

This paper concerns the capacity expansion problem of inter-regional water supply facilities, and presents a mathematical model to analyze the problem. The model postulates such an inter-regional water supply system that is managed by a body which is independent of municipalites ; and provides water to municipalities by conveying purified water to distribution reserviors in the municipalities through conduits laid between them. The formulated model, which belongs to a nonlinear programming, is solved by both an enumeration method and dynamic programming. A case study was conducted by applying the model to the capacity expansion problem in the region consisting of Takasago, Kakogawa and Akashi Cities in Hyogo Prefecture The calculated results show that such a management system as is presumed in the model, is economically effective mainly because joint expansion for the increased supply in several municipalities will save associated costs, provided that unnecessarily excessive expansion is avoided.