Water Utilities have invested substantially in rehabilitation or renewal of water mains, largely funded through quality enhancement programmes. For example, since 1990 over 20,000km of mains have been relined and almost 29,000km replaced in England and Wales. Immediate impacts on quality have been demonstrated with pre and post rehabilitation assessment (PPRA). However, there was an underlying assumption that the techniques provide additional benefits e.g. in leakage, capacity or reduced bursts. Such assumptions had influenced technique selection but there was little hard evidence to support and provide confidence in these economic justifications.
Water quality improvements still need to be completed and there is an ongoing requirement for rehabilitation to maintain serviceability. This project has quantified the effect of different rehabilitation methods on the performance of networks.
The impact of water main rehabilitation over 10 years has been measured and converted into valuable cost-benefit information for industry decision support tools. This enables planners to select the most appropriate and cost effective techniques. The seven participants in the project have access to data from real, historic experience and are able to use this to get maximum business benefits from future rehabilitation.