Multicriteria assessment of optimal design, rehabilitation and upgrading schemes for water distribution networks

The application of the analytic hierarchy process (AHP) to help select the best option for the long-term design and upgrading of a water distribution network is described and applied to a real-world network. The main criteria used are: reliability-based network performance; present value of construction, upgrading, failure, and repair costs; and social and environmental issues. The AHP is a versatile and robust tool that can handle both qualitative and quantitative data, based on a simple method of pair-wise comparisons. It has been applied elsewhere on various problems, but not on the long-term design and upgrading of water distribution networks. Herein, the pipes are sized to carry maximum entropy flows using linear programming, while the best upgrading sequence is identified using dynamic programming. The upgrading options considered include pipe replacement and/or paralleling. The time-dependent deterioration of the hydraulic capacity and structural integrity are also accounted for.