            JORGE PINTO, LUÍS AFONSO, JOÃO VARAJÃO, ISABEL BENTES Departamento de Engenharias Universidade de Trás%os%Montes e Alto Douro Quinta de Prados, 5001%801 Vila Real PORTUGAL tiago@utad.pt, lu.afonso@gmail.com, joao@varajao.com, ibentes@utad.pt HUMBERTO VARUM Departamento de Engenharia Civil – DECivil Universidade de Aveiro Campus Universitário de Santiago, 3810%193 Aveiro PORTUGAL hvarum@ua.pt ANTÓNIO DUARTE Departamento de Engenharia Civil Universidade do Minho Guimarães PORTUGAL aduarte@civil.uminho.pt JITENDRA AGARWAL Department of Civil Engineering University of Bristol Queen’s Building, University Walk, Bristol BS8 1TR, UK j.agarwal@bristol.ac.uk Abstract:  The main objective of this paper is to introduce an emerging theory of vulnerability of water pipe networks and, in particular, its theoretical concepts. It is based on the form of a network and follows a systems approach. The application of the theory is presented using an example of a simple water pipe network. The fundamental contribution of this theory is to enable the design of water pipes networks that are more robust. It can also be used to achieve a more efficient management of water supply systems. KeyWords:  Water pipe networks, vulnerability, water management, failure, system, quality.   Traditionally, an analysis of demand and capacities has worked well for most networked systems. However, with increasing complexity of systems and the changing nature of demands, that is no longer sufficient. There is a need to examine the impact of damage to a system. For this purpose, for structural systems a theory of vulnerability has been developed (see for example, [1%4]). This is a theory of structural form and connectivity which is able to identify the vulnerable parts of a structure. The concept of vulnerability is associated with the disproportionateness of the failure consequences in relation to the initial damage. Thus a structure is vulnerable when a small damage demand leads to a disproportionately large structural failure. The action that may cause initial damage can be of any type including human error or even an act of sabotage. These concepts are applicable to many systems [5]. Recent research has lead to the application of the vulnerability concepts to water pipe networks. The purpose of this paper is present this emerging theory of vulnerability of water pipe networks (TVWPN). Much of the previous work on pipe network analysis has been on optimization problems. This shows that maximum flow occurs in a loopless network but such a network is not robust. ADVANCES in WASTE MANAGEMENT ISSN: 1790-5095 172 ISBN: 978-960-474-190-8