Leeds Flood Alleviation Scheme Phase 1
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Leeds Flood Alleviation Scheme Phase 1


Costing in the region of £50 million, Phase 1 of the Leeds Flood Alleviation Scheme is one of the largest river flood defence schemes in the country. It comprises major construction work along the River Aire in the city centre and Holbeck extending a distance of more than 4.5km between Leeds train station and Thwaite Mills.

The scheme includes the installation of innovative, moveable weirs at Crown Point and Knostrop. The weirs can be lowered in flood conditions to reduce river levels ​and the threat of flooding. This is the first time that moveable weirs have been installed in the UK for flood defence purposes.

In addition to the building of the moveable weir at Knostrop, Knostrop Cut Island has been removed allowing the canal to merge with the River Aire. This creates additional flood water storage and helps to facilitate the flow of water along this stretch of the river which will help to lower water levels in flood conditions.​

Elsewhere, flood defences including embankments, terracing and riverside walls have been constructed along the River Aire in the city centre. Some of the riverside walls include sections of glazed flood panels. These sites include the former KPMG building and the residential areas at Dock Street and Victoria Quays.

Flood defences are also being constructed along the length of the Hol Beck which flows into the River Aire adjacent to Granary Wharf and low level embankments will increase the level of protection in Woodlesford. Traffic management measures will be in place from 6 February to 11 September to allow this work to go ahead. For further information, please see the Water Lane Traffic Management Plan (PDF 489KB) and our Traffic Management Measures on Water Lane document (PDF 71KB).

The Trans Pennine Trail between Old Mill Lane to Thwaite Lane Bridge is temporarily closed from 28 October to until further notice to enable seasonal tree planting to take place. A diversion will be put in place and this can be found in the TPT Closure Notice (PDF 2MB). We apologise for any inconvenience caused.

The defences will provide the city centre, including more than 3,000 homes and 500 businesses with protection against flood events from the River Aire and Hol Beck. It will also protect 300 acres of development land and open up key regeneration opportunities in the South Bank area. More than 22,000 jobs will be safeguarded over the next 10 years from the increased level of protection and through the scheme’s development and construction, 150 jobs and apprenticeships will have been created.

Additional funding

In December 2016 an additional £3.8million was awarded to further reduce the risk of flooding to Leeds City Centre.

The money, which was approved by the West Yorkshire Combined Authority Investment Committee on behalf of the Leeds City Region Local Enterprise Partnership, will focus on additional measures to reduce the risk of flooding within the Phase 1 area, including:

Increasing the standard of protection from 1 in 75 years to 1 in 100 years through the enhancement of current defences
Further analysis and design work since the scheme started in 2015 has found that the standard of protection can be lifted through a combination of measures including small increases to wall heights along the River Aire. Other measures are listed below.

Implementing surface water flooding protection measures
Surface water flooding protection measures will be achieved through a number of different interventions ranging from ‘no return’ flap valves in large culverts such as Meanwood Beck, to sealing outlets and property protection measures such as flood doors and windows.

Increasing the resilience of emergency response
By being able to respond to emergency situations quicker, the impact of an incident can be lessened and the damage caused repaired sooner. We are including a range of resilience measures to the structures we are building so that if needed, emergency maintenance work can be carried out quickly.

Enhancements to connectivity, environment and public realm
In addition to the new fish, otter and elver passages being introduced to improve biodiversity, the new section of Trans Pennine Trail will include ecological and wildlife improvements. The footbridge at Knostrop has been architecturally designed to enhance its surroundings and surfacing improvements are being make to public realm areas.

Stay up to date

The project team produces a regular newsletter which is available in the Documents section.


Click to expandScheme Features

Phase 1 of the flood alleviation scheme was initially designed to protect Leeds city centre (between Leeds station and Knostrop weir) from a flood event with the likelihood of occurring once every 75 years. However, with the additional funding awarded by the Leeds City Region Local Enterprise Partnership in 2016, the standard of protection is being increased to now provide protection against a flood that is likely to occur once every 100 years (or has a 1% chance of occurring in any given year). Work to increase the standard of protection will not affect the completion date for the scheme which is on track for summer 2017.

Key elements of the scheme include:

- Remove the existing weirs at Crown Point in the city centre and at Knostrop and install moveable weirs that can be lowered when the river is high, causing the water level to drop. An animation showing how the moveable weirs operate can be viewed on YouTube. In addition, a simulation of how the moveable weir is being installed at Crown Point can also be viewed.

-Construct linear defences such as low level embankments, terracing and riverside walls; at low points along the riverbank;

-Remove Knostrop Cut Island to merge the canal and River Aire which will help facilitate the flow of water when the moveable weirs are lowered as well as creating somee additional flood water storage;

-Provide flood defences along a length of HolBeck located on Water Lane;

-Provide defences to Woodlesford in the form of low level embankments to protect against a flood event that is likely to occur every 200 years (or has 0.5% chance of occurring in any one year);

-Details of the planning permission application can be viewed.


Click to expandLeeds FAS Project team

The Leeds Flood Alleviation Scheme is being delivered by Leeds City Council in partnership with the Environment Agency and supported by Arup. BMMjv (a joint venture between BAM Nuttall and Mott MacDonald) are working closely with the partnership to deliver the scheme.​

Click to expandFunding the scheme

The Leeds Flood Alleviation scheme is being funded by Leeds City Council, the Department for Environment, Food and Rural Affairs (Defra), the Environment Agency and the Department for Business, Innovation and Skills (BiS).​

Click to expandCity centre public rights of way closures

​​For more information please click on the link below.

City centre closures document

Click to expandTrans Pennine Trail closure and route diversion information

A section of the Trans Pennine Trail along Knostrop Cut has been closed to allow major construction of flood defences along the River Aire. The work includes the removal of the Knostrop Cut island and the relocation of the Trans Pennine Trail along the northern bank of the river. A temporary diversion has been signposted along the south bank of the river to provide an alternative route until the new permanent diversion is opened on completion of the scheme in summer 2017. You can download a map showing the route of the pedestrian and cycle diversion in the Documents section on this page.

To enable efficient construction of the Flood Alleviation Scheme and ensure safety of the public, there will be some additional closures to the Public Rights of Way (PROW) along the waterfront. Details of these closures and the associated diversion routes can also be found in the Documents section.​

Click to expandKey Project Milestone Summary

Description Start Date End Date
Project End Date - July 2017
Knostrop Weir January 2015 May 2017
Crown Point Weir January 2016 July 2017
Linear Defences January 2015 July 2017
Knostrop Cut March 2015 April 2016
New Trans-Pennine Trail May 2017 June 2017
River closures 15 February 2017 13 April 2017
15 May 2017 12 June 2017
21 June 2017 18 July 2017
​(*NB - Dates correct at time of publishing - January 2017)​​

Further information on work start dates can be found in the link below.​​

Construction commencement dates

Click to expandWhat do we mean by flood risk?

This is the chance of a flood happening. Generally, the higher the figure used in the description of the flood risk, the less chance of it happening. For example:

An area with the chance of flooding of a 1 in 75 (1.3 percent) in any one year has less chance of flooding than another with say an annual probability of flooding of 1 in 25 (4 percent).

It is important to understand that a 1 in 75 chance of flooding in any one year does not mean that level of flood will happen once every 75 years. Nor does it mean that if the flood hasn’t happened for the last 74 years, it will happen this year. ‘Any one year’ means exactly what it says, in that the risk is expressed on a yearly basis. A flood may also occur more than once in a year.

Click to expandWhy has this level of protection been chosen?

The scheme was originally designed to reduce flood risk up to a 1 in 75 year event. This was the highest level of protection which could be provided at the time with the funds that were available. Since receiving the additional funding from the Leeds City Region Local Enterprise Partnership, we have been able to increase the level of protection to 1 in 100 years while continuing to maintain the public’s access and enjoyment of the riverside.​

Click to expandHow does the introduction of moveable weirs improve flood protection?

Weirs keep river levels high to allow for navigation. By replacing fixed weirs with moveable weirs we will be able to lower river levels by up to one metre during flooding conditions, thereby creating additional capacity for flood water in the river channel.​​

Click to expandIs flood protection upstream of Leeds station planned?

Yes. Following the December 2015 floods, government committed an additional £35 million to reduce the risk of flooding to Leeds. Planning for Phase 2 of the Leeds Flood Alleviation Scheme is now progressing. The current Phase 1 of the scheme covers the section between Leeds train station and Thwaite Mills. Visit the Phase two page for more information.​​

Click to expandWill flooding risk be increased further downstream?

Our specialists carried out thorough assessments during the design stage of the scheme to ensure that one community is not protected at the expense of another.

The scheme will have a neglible effect on flood risk downstream of Thwaite Mills. Mitigation works have already been implemented in Woodlesford to give the area a 1 in 200 year SoP, whilst the impact on the remaining downstream areas is minimal due to the large areas of designated floodplain.​

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