Abstract

In the fifth report of the drinking water infrastructure (2013), the US Environment Protection Agency (EPA) had stated that a total of 384.2$ billion is needed in water infrastructure investments in United States over the next 20 years. About 247.5$ billion, which is 64.4% of this investment, is required for the transmission and distribution segments of the water infrastructure. Thus, it is essential that the water infrastructure functions properly to ensure the continuous supply of healthy water with the required pressure. The deterioration of water distribution networks leads to impaired water quality, increased leakage and breakage rate, and reduced hydraulic capacity. The development of inspection, maintenance, and rehabilitation plans is crucial to reduce the failure risk of deteriorated infrastructures. The performance indices of water distribution networks and their components help municipalities plan inspection and avoid crises due to pipe failures and breaks.
The main purpose of this research is to assess the performance index of water distribution networks by integrating the performance indices of its components (pipelines and accessories). The water distribution network is divided into three hierarchal levels: components, segments, and distribution network or sub-network. To assess the performance indices of water distribution network components, the critical factors affecting them were identified and studied. Three main groups of factors were identified, namely, physical, environmental and operational. Each of the three main groups is in turn sub-divided into a list of sub-factors. The Fuzzy Analytical Network Process (FANP) method was used to obtain the relative weights of the identified factors and sub-factors. These weights were used along with the effect values gathered from the experts to assess the performance index of the various components in the network. The performance indices of the segments were then assessed based on the components that make the segment. The performance indices of various segments were aggregated to obtain the sub-network or network performance using reliability analysis. Network performance could be utilized to prioritize the rehabilitation of components and segments and to construct comprehensive intervention plans for the entire network or sub-network. An Excel-Matlab® interface was developed to implement the developed models that perform the above mentioned procedure.
The resulting performance index, which represents the condition of the water distribution network, helps municipalities to minimize the number of scheduled maintenance activities and to predict the performance of the distribution network. This reduces health hazards and maintains the water supply safe, sustainable, and cost-effective.