The influence of pressure/leakage relationships from existing leaks in the benefits yielded by pressure managemen

Water loss in Water Distribution Systems (WDS) is now an issue of growing importance and greater efforts are being made to ensure the sustainability of these public services. In recent years the concept of Fixed Area and Variable Area Discharges (FAVAD) is the basis for several models developed to support the management and control of water losses. However, in many different real-world situations, the relationship between pressure and flow rates from existing leaks is not easy to estimate (different pipe materials exhibit different relationships) and usually is based on empirical approaches or field experiences. This paper presents the results from a study conducted to evaluate the influence of different pressure/leakage relationships on the benefit yielded by pressure management. To achieve this purpose, a methodology recently developed by the authors was conveniently adapted. The methodology follows the ‘water losses management international best practices’ and makes it possible to evaluate the benefits that can be achieved by pressure management in WDS, particularly in terms of water production reduction. It is based on the analysis of the minimum night flow and the FAVAD concept, and it uses a pressure driven simulation model to predict the network hydraulic behaviour under different pressure conditions. The results here presented show that the benefit yielded by pressure management can change significantly for different pressure/leakage relationship exponents (N1). In being thus, a special attention should be directed to this issue in pressure management projects.