Rehabilitation of existing intermittent water supply network under fund constrains using marginal increase in resilience to marginal increase in cost method

Abstract

[EN]The battle of intermittent water supply posed a tough challenge by jointly considering a problem related to analysis, design and operation of water distribution networks (WDNs). A methodology is needed which could summon all the inefficiencies of the existing network on a single platform to achieve the different stated objectives (Indicators) under some technical and financial constraints. The main targets are: (1) reduction in losses by repairing leaks, and/or replacing pipes, (2) to increase consumer satisfaction by meeting the demands at required pressure. A multi-stage methodology is proposed to suggest a solution to the given problem. Initially, demand nodes are clustered to form District Metering Area (DMA) by considering the locations of existing valves using the methodology of Sharma et al. (2022, Accepted for publication). The methodology of Sharma et al. (2022) consists of identification of clusters and their boundaries by considering the location of existing valves. The boundaries optimization is solved using Genetic Algorithm (GA) with customer satisfaction as a constraint to identify permanent boundaries. Out of the several ways of improving the network performance in desired 5-year periods with limited budget in each year, the leak detection and repair, pipe replacement with same or higher size, and valve installation to reduce excess pressure are proposed to be targeted primarily. A fast greedy algorithm, similar to that used by Gupta and Bhave (1996) for design of WDN and Agrawal et al. (2007) for strengthening and expansion of WDN, is proposed to be used. The iterative methodology will start with existing network. Benefits in terms of improvements in both head and outflows at demand nodes due to change in any option will be calculated along with increase in cost for that option. All the options will be considered one by one. Out of several options at any stage few best will be selected. The iterative process of selection for any year will be repeated till the available fund for that year are exhausted. Final solution for the first year will become, initial solution for the next year. Solution for all the five years will be obtained. Finally, the performance of network would be assessed using suggested parameters and the results will be reported. Gupta R. and Bhave P.R. (1996). "Reliability-based design of water distribution systems", Journal of Environmental Engineering, American Society of Civil EngineersAgrawal M. L., Gupta R., and Bhave P. R. (2007). "