Disconnection of surface water drainage: a local authority perspective

This paper argues the case for the disconnection of surface water from combined sewer systems drawing on experience gained from the European Interreg IIIB project ‘Urban Water’. Data and examples drawn from Netherlands and Germany are applied in the Local Authority area of Renfrewshire in Scotland. Disconnection is increasingly welcomed by local authorities to meet social, environmental and safety (from flooding) criteria. Unfortunately, traditional, bolt-on or end-of-pipe solutions tend to result in a degraded and piecemeal infrastructure which is expensive and difficult to manage or improve. Further, the limited availability of funding, and the acuteness of flooding problems, means that the more sustainable opportunities provided by watercourses can be readily overlooked. Disconnection of surface water focuses on controlling the water at source thereby providing a rationale for integrated use of land for water storage and other uses.

The disconnection options specifically applicable in Renfrewshire are reviewed and examined, drawing on experiences from the European case studies. The paper addresses the evaluation of disconnection options, the means of promoting disconnection and the value of disconnection targets. Results from disconnection programmes are presented, with information on methods, costs and savings. The paper concludes by presenting the disconnection targets used by the various parties involved in the project.