Brownfield redevelopment, pluvial flooding and climate change

Example of pluvial flooding

Introduction

This projects aims to evaluate whether there is potential to use brownfield land for urban flood risk management. Recycling brownfield land is currently perceived as a sustainable option for urban development because it avoids urban sprawl and associated negative impacts. However little consideration has been given to the potential that brownfield land may offer for managing flood risk in a sustainable manner. Urban areas have little room to manoeuvre to reduce flood risk as major changes in urban morphology and topography are costly and disruptive. But as brownfield land becomes available, albeit sporadically and in disconnected patches, is there an opportunity to adopt a long term strategy for sustainable management of urban flood risk? Is the impetus to redevelop urban brownfield land rapidly reducing our capacity to manage urban flooding problems, especially given the uncertainty surrounding climate change?

Pluvial Flooding

With climate change the UK is expected to experience more high-intensity storm events, leading to higher frequency and greater impact pluvial (rainfall) flooding. This may therefore lead to increased periods whereby the sewer system is running at capacity and therefore in effect out of commission. Changes in urban surface may therefore offer opportunities to build in capacity to deal with such events. Assessments made on a site by site basis make it difficult to detect opportunities to manage pluvial flooding. Such piecemeal approaches towards managing urban surface water may result in a loss of adaptive capacity to deal with potential changes in rainfall patterns. Ongoing developments in urban data resolution and modelling capabilities now make it possible to model urban hydrology in detail and quantify the potential reduction in flood risk that could be gained from various brownfield redevelopment scenarios (including small and scattered plots).

Research questions

Can brownfield redevelopment be exploited to manage urban pluvial flood risk?
How can brownfield redevelopment be used to manage urban flood risk?

Research Hypotheses

Brownfield redevelopment can be used to alter urban sub-catchments, overland flow pathways and surface storage.
Brownfield redevelopment, via changes in surface hydrology can be used to manage extreme rainfall events that exceed the capacity of the minor system.
A holistic (both in time and space) strategy for brownfield redevelopment can create capacity for an urban catchment to better manage urban flood risk given potential climate change.

Approach

Using selected case studies, a model based approach will be used to evaluate the potential that brownfield land may offer to manage future flood risk as part of a long term sustainable strategy. Results from a range of brownfield redevelopment scenarios coupled with climate change scenarios will be evaluated in terms of sustainable options for managing flood risk. The results from the research will contribute to the knowledge base being developed to support sustainable solutions for flood risk management.