Simplified approach to water distribution system management via identification of a primary network

The traditional approach to the design of water distribution systems (WDS) is based on the concept of topological and energy redundancy, resulting in systems with many loops and with nodal pressure higher than design requirements. In the early days of water supply networks, this oversizing was not seen as a problem. Currently, however, with aging water networks and pressure on utility finances, the cost of infrastructure maintenance and renewal constitutes a significant proportion of utility budgets. This paper proposes a novel approach that enables a water utility to better invest limited budgets by dividing the water system into a primary and a secondary group of pipes, with the former being the focus of the field investigation, maintenance, and renewal activities. The primary network is identified such that it guarantees the minimum hydraulic performance while achieving maximum topological redundancy in the overall system. The methodology is based on the use of local and global topological and energy metrics in conjunction with a heuristic optimization technique. A case study confirms that minimum nodal pressure can be substantially preserved by focusing activities on less than 70% of the pipes in the network, which means a reduction of over 30% of the total length of infrastructure and, consequently, of related field investigation and maintenance costs. The analysis of the local and global performance indexes also provides various insights and useful information for utility management.