Approach to assess undue inflows into sewers

Abstract

Urban water systems performance is essential for responding to challenges in urbanised areas that managers and other actors face today. Undue inflows to sewer and natural drainage systems are widely recognised as a major source of functional and financial problems. These problems identified throughout the world, contribute largely to systems' poor performance. A comprehensive performance-oriented methodology, aligned with the infrastructure asset management approach has been developed, including a specific performance assessment system (PAS), taking into account different decision levels as well as type of inflow, causes, underlying mechanisms and consequences. An overview of the proposed methodology and the specific PAS are presented. Validation and consolidation of the PAS is carried out in the iAFLUI collaborative project. This project involving 13 water utilities, representative of the Portuguese reality, ensures the coherence and feasibility of the methodology as well as the capacitation of the teams of the involved water utilities. Results obtained from the validation and consolidation of the PAS are presented and discussed. These confirmed that the PAS developed allows identifying the main problems and opportunities for improvement related to undue flows.