With storms on the horizon set to break up the latest heatwave, what’s the long term outlook for surface water management?

The Adaptation Sub Committee (ASC) to the Committee on Climate Change scrutinises the Government’s actions in relation to climate change adaptation and reports every two years on progress. The ASC’s 2017 Report to Parliament stated that the responsibility for managing surface water flooding is fragmented, mainly between water companies, highways authorities and Lead Local Flood Authorities (LLFAs). The report also concluded that it is unclear whether the actions carried out by these bodies are effectively tackling this challenge.

To help address this, we were commissioned by the ASC to research and define metrics to measure progress made in managing the risk of surface flooding at a local level, and based on the available data, collate these metrics to gain a national picture of the progress being made.

Managing the risk of surface flooding at a local level

Our research found that a national assessment of progress is challenging to present: data are either not currently collected or not consistent and comparable between Risk Management Authorities (RMAs). Broadscale estimates of risk exist, but there is no clear understanding of how investment by RMAs is reducing overall surface water flood risk. Since the Flood and Water Management Act introduced new responsibilities for local flood risk management, progress has been made by RMAs, but the approaches taken can vary remarkably between the 152 LLFAs in England and understanding the overall impact of work on reducing flood risk across the full spectrum of RMAs is not always possible.

The research recommends a prioritised approach to future data collection in relation to metrics that cover understanding of risk, ways of working and delivery of outcomes. At a strategic level, there needs to be clear responsibility and funding for data collection and collation, national expectations are needed with regards to partnership working and local asset management and investment needs to evidence shared outcomes across RMA boundaries.

Click to read the research to define metrics for surface water flood risk management.

Defra surface water management action plan

The study was timely, as earlier in July, Defra published its action plan for surface water management, fulfilling a recommendation from the National Flood Resilience Review, 2016. This was informed by research into local approaches to managing surface water flooding that came to similar conclusions as our research report for the ASC.

The Action Plan recognises that surface water flooding is a growing challenge; our climate is warming and hot and dry periods, such as that experienced recently, give rise to a higher chance of intense thunderstorms and surface water flooding. In addition our infrastructure is ageing and many of the drains and sewers in our towns and cities date back to the Victorian era and were not designed to drain the extra development that has occurred over the last 150 years.

New development is also continuing to add water into the system and even with Sustainable Drainage Systems in place, development of greenfield sites can still contribute more water. Smaller and infill developments can fall through the flood risk planning net, where they are the larger non major developments that are subject to less scrutiny from RMAs.

Click to read the action plan Defra surface water management action plan.

Surface water management needs co-ordinated action; currently the responsibilities for maintaining the drainage system are fragmented and complex. Flooding can be caused by capacity issues or failing assets in any one part of the system and there are significant interdependencies – the locations where water comes out of the system, such as highway gullies, may not be those that cause the problem – this could be from an overloaded sewer or blocked watercourse further down the system.

The Surface Water Action Plan picks up on some of the well-known challenges for LLFAs: that there are a variety of approaches to and capacity for surface water management, that roles, responsibilities, priorities and plan making are fragmented, and that it is challenging to deliver a surface water scheme via a system and process largely designed for major river and coastal schemes.

Proposed metrics set out in the ASC study will be useful to help monitor and measure how effective the action plan and emerging work by others, such as the Water Industry led Twenty First Century Drainage Project, will be and the need for future and perhaps more radical changes to the arrangements for surface water management.

Want to know more?

If you would like to know more about how we can help you with surface water flooding, please visit our local flood risk management webpages or email Hannah Coogan, Technical Director for Flood Risk Management.

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