Development and application of a framework to understand the available capacity in the UK’s drainage systems

The vision of the 21st Century Drainage Programme is to enable the UK water industry, in partnership with the UK’s governments and regulators, to take action now that will ensure the resilience and sustainability of our drainage infrastructure in the future. As part of this Programme, Workstream 2 has been focused on understanding the available capacity in the UK’s foul and combined drainage systems to accommodate present-day flows and flows expected in the future. The first phase of this work resulted in The 21st Century Drainage Programme Capacity Assessment Framework - a consistent, transparent and high-level approach to assessing available capacity and investment needed in the long term. This paper describes the approach adopted by the Framework (completed in April 2017) for assessing performance and investment (present day, future and future with intervention), the metrics used by the assessment and how this information is to be visualised. This paper also introduces the second phase of work, which is currently underway, supporting all 12 of the UK’s sewerage undertakers as they embed the Framework into their organisations. This includes the development of a first draft National Picture of present day drainage capacity, due for publication in late November 2017