Opportunity
Leeds is in a catchment where river levels can rise rapidly in response to rainfall and there is rising risk of fluvial flooding.
To protect the city and its almost 800,000 residents, the council and Environment Agency are combining traditional engineering methods and natural flood management (NFM) to improve defenses and build resilience.
The project will introduce NFM across the 270 square miles (700 square kilometers) of the River Aire catchment, from Armley west of the city center to Malham in the Yorkshire Dales. It is the largest NFM project in the UK.
Solutions
As part of our work to identify and deliver the most appropriate and effective NFM projects across the catchment, we developed a suite of innovative geographic information system (GIS) tools to provide a consistent approach.
We also created a risk-based leaky barrier tool to help pinpoint the best locations for installation, and a Woodland Carbon Code tool to estimate carbon sequestration from the creation of woodland.
Our nature-based interventions have been tested at several pilot sites. These include the following:
- Detailed designs to reduce flood risk and maximize opportunities to enhance the environment at Marlfield Farm: including swales, bunds, leaky barriers, and ponds.
- Linking NFM, rewilding, and well-being in line with the landowner’s vision for an estate covering more than six square miles (16 square kilometers) in the Upper Aire region.
- An NFM concept design at Bodington Playing Fields, part of the University of Leeds. This includes planting almost 4,000 trees and hedges, and creating wetland scrapes (shallow ponds) to control stormwater. The concept design will showcase natural solutions, improve stakeholder engagement, and provide opportunities for academic research to enhance our understanding of the multiple benefits of these nature-based solutions.
Outcome
Our systematic, repeatable, and auditable process for managing the development and delivery of NFM solutions will be used at hundreds of sites across the catchment. Key to its success is our GIS platform, which will facilitate the advance of a pipeline of sites and lead users from feasibility to concept design, then delivery and ongoing management of the assets.
Millions of new trees and other vegetation will be planted to capture and store carbon, promote biodiversity, and create new habitat, and to intercept and slow the flow of rainwater into the River Aire. Runoff pathway management, and river and floodplain management interventions such as leaky barriers, will be implemented to store and slow the flow of water in the uplands.
Overall, NFM will improve the climate resilience of the city of Leeds and other communities throughout the catchment and will deliver wider benefits for people and nature.