Integrated Performance Assessment Model for Water Networks

Abstract

Most water distribution systems worldwide are deteriorating rapidly, while their rehabilitation costs are on the rise. Maintaining water networks in a proper condition under a tight budget puts extra pressure on municipalities and triggers the need for a proper performance assessment. This research therefore aims at developing an Integrated Water Networks Performance Assessment (I-WNPA) model to assess the performance of water networks. It also presents a functional (physical, operational, quality of service, and environmental) and global (or total) performance index scale of different performance states, the description of each state and recommended intervention actions (long term, short term, or immediate). The model encompasses three main phases for utilizing the fuzzy analytic network process (FANP) to calculate the weights of functional performance criteria of the components in the first phase. It also uses both the preference ranking organization method of enrichment evaluation (PROMETHEE) and the simple multiattribute utility theory (MAUT) to compute the functional and global performance indices of the network components. Then, the probability-of-failure–based integration method is developed to integrate the component indices and to obtain the segment performance index (SPI). The topological clustering is adopted to integrate SPI to obtain the entire network index, using the topological chart of the network and the connectivity ranked matrix. In this research, data are obtained from questionnaires and case study databases. The proposed model is demonstrated via the data covering water subnetwork in the city of Montreal. The results are well aligned with Montreal water services assessment as follows: Excellent for 16 pipes and 49 accessories, good for 32 pipes, medium for 5 pipes and 8 accessories, and poor for 21 accessories. The results also show that the analyzed subnetwork is in a medium state. These results are used to identify and prioritize the most vulnerable components, subnetworks, or the entire network, and subsequently to identify the performance improvements required. The model can be linked to other models, such as rehabilitation planning and budget allocation. This approach suits any unidirectional (one-way flow) water network, and it can be adopted to support the performance assessment of any water network by considering hydraulic analysis and automation means. It can also be adopted by other infrastructure systems, such as sewer networks and subway systems, when suitable indicators are defined.