Session: management of drainage near source – disconnection/minimise surface water entering public drainage

Many combined sewer networks are currently constrained due to lack of capacity. Surface water entering the network may have an impact on the local environment by causing additional spills from Combined Sewer Overflows (CSOs) and flooding events. With the increasing number of developments taking place in Scotland, more and more demands are being placed upon the existing wastewater assets and infrastructure of the drainage utility, Scottish Water. The principal way of preventing these CSO spills/flooding event s is to reduce the number of surface water connections to the combined sewer network and promote more surface water discharges to nearby watercourses.

The problem is being addressed by examining all development applications as they are considered by a drainage planning officer in the water authority. The research reported in this paper is investigating the conditions under which it is reasonable and practical for Scottish Water to accept surface water flows into its combined sewer network . This paper presents a summary of the initial findings of the research to date by examining a sample of the sites examined. The objective of the work is to develop a methodology to support a rigorous stance on the acceptance of surface water flows into the combined sewer network. The results have not as yet been obtained.