Multi-criteria analysis applied to ranking rehabilitation strategies of water distribution networks

Rehabilitation of water distribution systems is a complex task that water companies have to tackle continually to keep high-quality service. The larger and more complex the network, the harder to make decisions about the network maintenance strategy to be implemented. Considering pipe replacement as a strategy for water network rehabilitation, this work presents a combination of water distribution system analysis and multi-criteria analysis to rank alternatives for pipe replacement. A set of eight performance criteria is used to evaluate the rehabilitation alternatives. The Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) is herein adopted to rank the solutions, coupled with a final sensitivity analysis on criteria weights. The obtained results point out as pipe replacement is an essential strategy for rehabilitation since the eight evaluation criteria are improved. The sensitivity analysis shows the best solutions' robustness, with just a few variations in their position in the ranking. The most frequent best solution is then hydraulically evaluated, showing the real benefits of pipe replacement in terms of pressure deficit reduction.