Groundbreaking £200m scheme to protect from flood risk

A groundbreaking major project featuring pioneering technology to protect Leeds and surrounding areas from the risk of extreme flooding is now complete.

After more than a decade of work and an investment of £200million including the use of state-of-the-art engineering and infrastructure, the Leeds Flood Alleviation Scheme led by Leeds City Council in partnership with the Environment Agency offers dedicated flood defences to help protect more than 4,000 homes and over a thousand businesses along the River Aire catchment in Leeds and neighbouring communities. It will also help protect more than 33,000 jobs in Leeds alone.

Completion of construction of the scheme was officially marked today with a celebration event at a new flood storage area by the riverside near Calverley in Leeds hosted by the Leader of Leeds City Council Councillor James Lewis joined by representatives of project partners the Environment Agency, BAM Nuttall and Mott MacDonald, along with technical advisors AECOM, Bradford Council and other key stakeholders.

The impact of the scheme offers a one-in-200-year level of protection plus climate change allowance against extreme flooding along the River Aire, as experienced following Storm Eva at Christmas 2015 which caused an estimated £36.8million in direct costs of damage in Leeds and more than £500million in recovery costs to the wider region.

The Leeds Flood Alleviation Scheme has been carried out in two phases. The first phase, completed in 2017, saw the creation of new moveable weir gates across the river at Crown Point and Knostrop together with merging work to the river and canal at Knostrop supported by new flood walls and embankments covering 4.5kilometres through Leeds city centre and downstream to Woodlesford in keeping with the surrounding areas. The use of moveable weirs able to be raised and lowered to control river levels was the first time such technology had been used for flood defences in this way anywhere in the UK.

The second phase covering the city centre and upstream has been much larger in scope. Construction began in 2019, with engineering and infrastructure works carried out along 14 further kilometres of the river from Leeds City Station upstream along the A65 Kirkstall Road corridor to Apperley Bridge. It includes new raised flood defence walls, embankments, flow control structures and the removal of obstructions at various points through Armley, Kirkstall, Newlay and Apperley Bridge as well as protecting the historic Kirkstall Abbey site.

A key feature of phase two is the largest infrastructure element of the entire scheme, the creation of a new controlled flood storage area near to Calverley. Chosen to be in a location away from populated areas, it has been designed to hold up to up to 1,800,000m3 of floodwater (equivalent to 720 Olympic-sized swimming pools) temporarily in the event of extreme rainfall and river levels. The 200-metre long structure features two new moveable flood gates which can be raised and lowered to slowly release the water downstream in a controlled way once the threat of flooding has passed. To see a timelapse video of the construction of the site visit https://youtu.be/XD5qXlUMgrU.

Alongside the infrastructure and engineering works, the scheme also has a strong focus on using the environment and nature to help protect against flooding, in one of the largest and most innovative natural flood management projects seen anywhere in the UK.

Stretching from Apperley Bridge to the source of the River Aire at Malham approximately 40 miles upstream from Leeds (64 kilometres away), the range of measures includes the planting of around 750,000 trees and soil and land management measures across 1,700 football fields’ worth of land (1240ha) in the upper Aire catchment. This work, managed by the Environment Agency in partnership with Leeds City Council, White Rose Forest and Yorkshire Wildlife Trust, will capture and slow the flow of water down the river and aims to reduce peak flows by up to five per cent, further enhancing the overall effectiveness of the flood scheme and allowing it to adapt to the impacts of climate change through to 2069.

The scheme brings additional benefits to the environment through the creation of vast new areas of habitat for wildlife, improved water quality and farmland as well as restoring previous habitats.

The installation of fish and eel passes at the moveable weirs in the city centre have been a contributing factor to otters and salmon being seen in parts of the river for the first time in over 200 years since the completion of phase one, which is a major sign the scheme is already improving the quality, biodiversity and resilience of the river system.

Additionally, a 2.4-hectare wetland habitat on Kirkstall Meadows has been created, while more than 90,000 further trees and shrubs have been planted throughout the Leeds area of the scheme.

A further key economic benefit of the scheme includes bringing land previously unsuitable for development due to flood risk back into potential use, opening up significant areas of land to support the growth of the city with estimated regeneration benefits of £774million over 10 years and potentially more than 3,000 new jobs. Examples of this can already be seen in the developments around Wellington Street and Holbeck since phase one was completed in 2017.

The protection offered by the scheme also offers increased resilience for key infrastructure in Leeds including power supplies, communications networks, and key travel routes. These include the railway at Kirkstall, which connects a significant portion of Yorkshire and had previously been at significant flood risk causing regular disruption to rail travel throughout the region.

A focus during construction of the scheme has been to limit the carbon impact of the works. This has seen the use and recycling of materials across flood defence sites, including the use of nearby clay to form the embankments at the new flood storage area, saving more than 5,000 lorry journeys.

A study carried out by the University of Edinburgh Centre for Carbon Innovation also highlights the value of the Leeds Flood Alleviation scheme, stating that if the scheme is operated at its full potential just once, it will have saved more carbon than it used to build it, based on the carbon impact from the destruction and clean-up caused by Storm Eva. Therefore the scheme will be making a significant contribution to the council’s net zero ambitions every time it needs to be operated.

Leader of Leeds City Council Councillor James Lewis said: “This is a very important and proud day for our city as the Leeds Flood Alleviation Scheme can now help protect thousands of homes, communities, businesses and jobs across Leeds and beyond from the increasing threat posed by flooding and climate change. We all remember the devastation and misery caused by Storm Eva and recent extreme weather events, and the confidence this scheme offers will be immeasurable in our city for decades to come.

“This has been a mammoth project, one of the biggest ever undertaken in Leeds in terms of its importance, scale and ambition, and everyone involved in it can rightly be proud of the part they have played, especially all those who campaigned and worked so hard to ensure it would be completed in full as quickly as possible. As a city we say thank you to everyone who has helped make this scheme a reality, for the benefit of all those who live and work in Leeds and beyond.”

Mike Dugher, Yorkshire Area Director for the Environment Agency said:
“Communities across Yorkshire have repeatedly experienced the devastating effects flooding has on lives and livelihoods. The Leeds Flood Alleviation Scheme exemplifies the power of partnership in achieving remarkable outcomes, integrating civil engineering works with natural flood risk management in the upper catchments, significantly reducing flood risk to Leeds city centre and the surrounding areas.

“We continue to work hard to increase flood resilience across Yorkshire, however, as winter approaches, always encourage people to be prepared, know their flood risk and sign up to our free flood warning service to give yourself valuable time when flooding is predicted.”

Tracy Brabin, Mayor of West Yorkshire, said: “We’re building a greener, more secure West Yorkshire that’s resilient to the effects of climate change.

“Today, thousands of households and businesses across Leeds can breathe a sigh of relief, safe in the knowledge that their great city is better protected than ever against flooding.

“I commend the tireless work of the council and its partners to deliver this groundbreaking scheme, to help ensure that we never again have to face the same devastation of the 2015 Boxing Day floods.”

John Wilkinson, chief operating officer, BAM UK & Ireland, and Richard Risdon, Mott MacDonald UK & Europe managing director said: “The BMMJV is proud to be part of this major engineering project that has been led by Leeds City Council and the Environment Agency to use innovative engineering solutions in combination with natural flood management. The combination of solutions delivered is the result of the partnership approach taken by everyone involved, to maximise the benefits to the city, while minimising the carbon and visual impact.

“The impact of Leeds Flood Alleviation scheme extends far beyond our involvement over the last ten years. This enhanced flood protection provides climate resilient flood protection for the city, and helps further unlock Leeds’s immense regeneration potential in the years ahead.”

Will Barnett, director of Water, UK & Ireland, AECOM said: “Wetter winters, drier summers and increased rainfall linked to climate change means that many parts of the UK – including Leeds – are at greater risk of flooding over time. The Leeds flood alleviation scheme sets a new standard for integrating traditional engineering methods and nature-based solutions at a catchment-wide scale. As technical advisor to Leeds City Council, fostering collaborative partnerships across the wider delivery team has been key to the project’s success. We’re proud to have played our part in the delivery of this critical flood defence project, reducing the risk of flooding to the people, homes and businesses of Leeds for decades to come.”

Multiple funding streams have contributed to the Leeds Flood Alleviation Scheme, including government Grant in Aid funding, local funding from Leeds City Council, over £20million of regional funding from the West Yorkshire Combined Authority, and funding from others including: the Leeds City Region Enterprise Partnership, the European Regional Development Fund, Network Rail, The Woodlands Trust and others.

It is important people remember even with new flood defences in place, people can never be fully protected from flooding. We encourage people to be prepared, know their flood risk and sign up for the Environment Agency free flood warnings. Visit www.gov.uk/prepare-for-flooding to find out more.