Methodological Approach for the Rehabilitation of Water Distribution Systems: Case Study Application Based on the CARE-W System

Rehabilitation is nowadays a hot topic of the agenda of most European water supply stakeholders. Many existing water mains have reached their expected lifetime, and high capital investments are required to renovate them. Well-devised methodologies for rehabilitation planning are needed, in order to define what, when and how to rehabilitate water transmission and distribution networks. However, rehabilitation can be motivated not only by asset ageing, but also by a combination of other concurrent factors, such as unsatisfactory hydraulic performance, water quality problems (e.g. color, taste, smell, lead), need for expansion, insufficient reliability, high level of water losses, etc. Comprehensive and well-devised methodologies for rehabilitation planning are therefore needed. This paper proposes a general approach to network rehabilitation and uses the case study of Brandoa (Amadora, Portugal) to illustrate it. This network was selected because the identification of a good rehabilitation solution in this case is far from obvious. The network presents a combination of problems, such as excessive pressure problems in some areas, insufficient pressure in other areas, material ageing symptoms in some pipes and very high service connection failure rate. Conversely, Brandoa is a problematic area in social and urban organization terms, having started as an illegal settlement in the 50's. The implementation of the recommended rehab methodology is supported on the use of CARE-W tools, complemented with network simulation and with a Technical Performance Assessment tool. The CARE-W system (Computer-Aided Rehabilitation of Water Networks) was developed under a project of the 5th Framework Program of the European Union and aims for assisting water utilities in setting up strategic and tactical rehabilitation plans. The project ended in 2004, and since then a number of applications took place in various countries. Challenges, constraints and objectives depend on country to country and case to case, and the experience achieved is vital to allow for transforming the current prototype system into a fully developed and professional tool. In Portugal, we aim for enhancing CARE-W prototype, transforming it into a professional software application that is easier to use, is better adapted to the Portuguese context, and is complemented with some new features. This paper was presented at the 8th Annual Water Distribution Systems Analysis Symposium which was held with the generous support of Awwa Research Foundation (AwwaRF).