Efficiency Study of a Pilot Water Distribution System Using EPANET and ArcGIS10 S. Mohapatra, S. Kamble, A. Sargaonkar & P. K. Labhasetwar National Environmental Engineering Research Institute, Nagpur, India sanjeeb_sanjaya@yahoo.co.in Sridevi. H Manipal University, Manipal, India S.R. Watpade Nagpur Municipal Corporation, Nagpur, India KEYWORDS Water Distribution System, continuous water supply, intermittent water supply, leakage, EPANET ABSTRACT: Hydraulic integrity problem is mostly associated with the water distribution system (WDS) of developing countries. The problem of integrity of network is further exemplified by deteriorated condition of network that leads to high leakage rates. In the present study, the performance of the WDS in a pilot study area of Nagpur city (India) is evaluated using EPANET software. Both continuous as well as intermittent water supply simulations are performed. ArcGIS10 is used to generate the maps of water supply network, node network, and elevation map. Remote sensing image is used to generate the population data. The HydroGen extension to ArcView which is a series of Avenue scripts is used to create hydraulic model data input files for EPANET. Model simulation results obtained using EPANET for the both supply modes identify critical areas with respect to pressure drop at various nodes. The suggestions made for controlling leakage and maintaining hydraulic integrity of the system are useful for the municipal authority for implementing 24×7 water supply scheme. 1. INTRODUCTION Water has always been acknowledged as a primary good and an indispensable natural resource. As the standard of living increases; so does the need for consumption of water for various anthropogenic activities. In general, more people use more water. Even if the amount used individually is reduced by education, the implementation of conservation practices or technological improvements in water distribution systems (WDS) are must. A typical WDS consists of network of pipes, nodes linking the pipes, storage tanks, reservoirs, pumps, additional appurtenances like valves (Rossman, 2000; Walski, 2003). A common problem in developing countries is that WDS are designed for continuous supply mode, but are operated in intermittent supply mode which leads to hydraulic integrity problem (CPHEEO, 1999). In intermittent supply, the duration of water supply is variable; it may be 1-2 hour per day or 3-4 hour per day (Peter, 2006). This water supply mode is very common in many cities in India (Jethoo, 2011). It is important to note that the hydraulics of the intermittent water supply is different than that of continuous water supply. A continuous water supply is based on “Demand driven analysis”, while the intermittent water supply is “Pressure/head dependent”. The softwares including EPANET developed for network analysis are based on the “Demand-driven” assumption, wherein, the nodal demands are assigned fixed values and the problem is to find pipe flows and nodal pressures that are hydraulically consistent with these demands, whereas in intermittent water supply, the demand is a function of pressure. Serious risk to public health, customer inconvenience and problems of water quantity and quality are the major drawbacks of an intermittent water supply system. Ineffective water supply and demand management, operational inadequacies unduly weaken the physical infrastructure in many urban areas. As the pressure to fill the gap in water and sanitation access grows, many people are making a case that all the nations of the world, particularly the poor ones, should go beyond just planning for basic water access and aim for 24x7 water supply. Thus the municipal water sector in recent years has been subjected to a process of constant changes. Today