Asset management of sewerage systems: the Indigau and GompitZ tools, from the state of the sewerage networks to the planning of their rehabilitation

Abstract

Asset management of sewerage systems is a growing concern for network managers. A buried asset, it is often misunderstood. Although it has a relatively long lifespan, some networks are beginning to date now, raising fears of large and costly renewal needs for the decades to come. This paper introduces two complementary models, Indigau and GompitZ, issued from projects in which various research teams, network managers and consultants have worked. Initiated in the European project CARE-S (Computed Aided Rehabilitation of Sewer networks), between 2002 and 2005, and the national RERAU project (rehabilitation of urban sewerage networks) between 2000 and 2004), both models are based on closed circuit television inspection data (CCTV) to describe the network status and pipe environment data. Indigau proposes a prioritization tool to rehabilitate sections in the short term, it is a tool based on multiple criteria and taking into account data on malfunctions and socio-economic criteria for the impact of failures. GompitZ allows long-term simulations, designed on a probabilistic modeling, and statistically based on CCTV data and pipe characteristics, coupled with a collector sensitivity model in the ROCA tool developed by Lyonnaise des Eaux, it enables to simulate the long-term effect of rehabilitating the most at-risk sections. The implementation of these models on the Caen and Bordeaux networks is described.