Flooding and the Boston Barrier
Everything you need to know about the Boston Barrier …
The Boston Barrier partnership is between the Environment Agency, Lincolnshire County Council, Boston Borough Council and Black Sluice Internal Drainage Board, who are all working together to reduce the risk of tidal flooding to over 14,300 properties in Boston.
Boston Barrier Community Hub
Residents can visit the Community Hub, Marsh Lane in Boston, to find out the latest information about the tidal barrier and meet with the project team to ask any questions.
The Environment Agency opens the community hub on Wednesdays from 12am to 7pm - although it may open more at key periods as the tidal flood scheme progresses. It will also be a place to find out more about the other Environment Agency projects happening in the area.
The tidal flood defence remains on track for a workable defence to be in place by December 2019.
The images below show what the barrier could look like
The picture below is a computer generated image showing what the flood on 5 December 2013 might have looked like above Boston town centre. The flood happened at night so this is a reconstruction we have produced using information about how the flood happened.
The Boston Combined Strategy was published in March, 2008, after extensive consultation. The strategy aims to “manage the risk from tidal flooding in Boston whilst enabling opportunities for regenerating the town’s waterways”.
When the barrier is built and the banks immediately downstream are raised, Boston will be protected from a tidal surge with a 0.3% annual probability (or 1 in 300 chance of happening in any one year). Unfortunately, we cannot protect against the most extreme tidal surges, but the barrier will protect Boston in most cases and give the town one of the best standards of protection against tidal flooding in the country.
Where will the barrier be located?
We want to try and explain why the barrier is being built in the right place and why the mouth of The Haven was discounted.
The purpose of the Boston Combined Strategy was to “determine a 100 year strategy approach to flood risk management and navigation improvements in Boston.” This strategy identified a multi-functional barrier, as the best solution for addressing flood risk management and waterway objectives in Boston.
A structure downstream of the port has many disadvantages, including:
- Navigation has to be maintained at all times. During construction we would be required to create a large bypass channel to accommodate shipping vessels
- Environmental damage to The Wash - an internationally designated site.
- Problems with access for construction plant and machinery.
- Problems with utilities (e.g. mains electricity supply).
- Increased cost of a larger and more complex barrier to prevent/limit collision damage and allow port vessels to navigate through.
For the reasons above, the Boston Combined Strategy discounted a barrier downstream of the port.
Water Level Management
Water Level Management (WLM) was proposed to create a safe and reliable non-tidal link between The River Witham at Grand Sluice and Black Sluice Lock on the South Forty Foot Drain– forming phase 2 of the Fens Waterways Link (FWL). As a key partner in the project, Lincolnshire County Council committed £11million towards WLM. Further economic studies in 2014 confirmed that most benefits for Boston come from holding high water levels for as long as possible and attracting leisure boats from the sea as well as from our inland waterways.
However, this needed further appraisal work. Therefore, following a Lincolnshire County Council Executive Committee decision in February 2015 and a Project Board confirmation in spring 2015 it was agreed that the work surrounding WLM should not delay the tidal flood defence project.
Water Level management has now been removed from the scope of the Boston Barrier project and Lincolnshire County Council have separated their £11million contribution from the scheme. They are reviewing how best to invest the funding to maximise its regeneration impacts and to allow additional fund raising opportunities to be identified.
Will the barrier increase flood risk along the Haven?
The barrier will not increase flood risk along The Haven. This is because a tidal surge happens differently to river flooding. A tidal surge happens much like a spring tide only the tide comes in higher. As the North Sea level rises, it moves through the Wash and into The Haven until it meets a hard defence or high land. It is the level of the North Sea that dictates what height The Haven rises to. Even if the channel of The Haven was dredged to increase depth and width, because there is always more water in the North Sea than there is capacity in The Haven, the level in The Haven will always match the North Sea. Putting a barrier in the Haven would not make the height of a tidal surge any higher or lower than it would have been anyway.
Will Boston town be better protected than communities along the Haven?
Once the barrier is built, communities along the Haven and the town itself will have exactly the same protection from tidal flooding. The maximum height that the barrier can hold water in the Haven is governed by the height of the Haven banks. Once the low spots have been raised, this will be a minimum of 6.3 metres Above Ordnance Datum.
How have Boston residents been involved?
Before the business case was developed, the Environment Agency engaged with key partners and the local community on the concept of a multi-functional tidal barrier in Boston and how this would reduce flood risk and help to regenerate the town. There were a series of drop-in sessions in 2011 to provide an opportunity for local residents and businesses to comment on the location of barrier. There was good attendance from local residents living near the proposed barrier location. A key element of the project will be extensive consultation with the local community, river users and businesses on how they want the landscape around the tidal barrier to be constructed.
Got any questions or want to receive updates about the Boston Barrier?
If you have any questions about the Boston Barrier or if you’d like to receive updates about the project then please contact:
Write: Boston Barrier Hub, Riverside Industrial Estate, Marsh Lane, Boston, PE21 7PJ