Flood Alleviation Scheme
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Flood Alleviation Scheme

The £45million Leeds Flood Alleviation Scheme (FAS) is one of the largest river flood defence schemes in the country. It will see major construction work along the River Aire in the city centre and Holbeck extending 4.3km between Leeds train station and Thwaite Mills.

Flood risk is increasing throughout the UK and in recent years Leeds city centre has come close to flooding several times. There are no formal flood defences along the River Aire.

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

The main construction works started in January 2015 and the project end date is May 2017.

The defences will provide the city centre and over 3,000 homes and 500 businesses with protection against flood events from the River Aire and the Hol Beck. It will also protect 300 acres of development land and open up key regeneration opportunities in the South Bank area. The scheme will also help safeguard 22,000 jobs over the next 10 years and create 150 jobs and apprenticeships to work on the project.​

Initial work on the Leeds Flood Alleviation Scheme saw defences constructed at Woodlesford during 2014, providing residents with protection against a one in 200 year flood event from the River Aire.​

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

Click to expandScheme Proposals

These proposals to protect Leeds city centre (between Leeds station and Knostrop weir) from a flood event likely to happen once every 75 years. The likelihood of a 1 in 75 flood event occurring in any given year is 1.3%.

-Remove the existing weirs at Crown Point in the city centre and at Knostrop Cut and install moveable weirs that can be lowered when the river is high, causing the water level to drop. An animation showing the typical operation scenario of the two weirs can be seen, via youtube, by using the ‘Moveable Weir Animation’ link under the external links. In addition, the proposed construction methodology for Crown Point Weir can be viewed from the same area using the ‘Crown Point Weir construction sequence’ link.

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

-Remove Knostrop Cut to merge the Canal and River Aire which will create additional flood water storage and help to lower water levels in flood conditions;

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

-Provide defences to Woodlesford in the form of low level embankments to achieve a protection against a flood event that is likely to occur every 200 years;

-Planning permission for the movable weirs has been granted. Details for this can be viewed by using the ‘Planning Permission Weirs on the River Aire’ link under the External links heading.​​

Click to expandLeeds FAS Project team

The Leeds Flood Alleviation Scheme is being delivered by Leeds City Council working closely with a project team including construction contractor BMM (a joint venture between BAM Nuttall and Mott MacDonald), the Environment Agency, Arup Mouchel, Dyrhoff, Canal Rivers Trust and Yorkshire Water.​

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

From 23 February 2015, a section of the Trans Pennine Trail along Knostrop Cut will close to allow major construction of flood defences along the River Aire, which will provide protection to thousands of homes and businesses. The work includes the removal of an island at Knostrop Cut and the relocation of the Trans Pennine Trail along the northern bank of the river. A temporary diversion will be in place along a safe and signposted alternative route until the new permanent diversion is expected to open in December 2016. You can download a map showing the route of the pedestrian diversion in the Documents section.​

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 be found in the Documents section of this page - City Centre PROW closures.

Click to expandKey Project Milestone Summary

Description Start Date End Date
Project End Date - May 2017
Knostrop Weir January 2015 April 2017
Crown Point Weir January 2016 April 2017
Linear Defences January 2015 November 2016
Knostrop Cut March 2015 April 2016
New Trans-Pennine Trail February 2016 September 2016
River closures 2 November 2015 30 November 2015
1 January 2016 29 January 2016
1 March 2016 31 March 2016
​(*NB - Dates correct at time of publishing April 2016)​​

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 current agreement Government has with the Association of British Insurers (ABI) is that ABI members make flood insurance for domestic and small businesses available as a feature of standard household and small business policies if the flood risk is no significant - this is generally defined as no worse as 1 in 75 annual probability of flooding.​

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

​The river level is held artificially high by the existing weirs which were built to allow navigation. The proposed movable weirs will, in a flood event allow the river levels to drop by up to 1.0m.​

Click to expandIs flood protection upstream of Leeds Station planned?

​The scheme will protect the city centre section and not sections upstream of the train station. Future phases will include addressing flooding upstream of the station, however, these will be subject to the availability of future funding.​

Click to expandWill flooding risk be increased further downstream?

​The scheme will have an immeasurable effect on the risk of flooding downstream of Thwaites Mill. There are large areas of designated floodplain from the Mill downstream.​​

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