Views sought on Environment Agency’s multi-million pound Lymington coastal flood strategy
Hurst Spit could be overtopped and salt marshes lost without significant investment in sea defences, coastal experts have warned.
Environment Agency plans are being drawn up in collaboration with local councils to set out how the coastline between Hurst Spit and Lymington will be protected and managed over the next century.
Hundreds of millions of pounds will be needed for the strategy, which could involve realigning sea defences, managed retreat and the construction of much taller and wider sea defence walls in urban areas.
The work will focus on protecting around 400 low-lying homes in Keyhaven and Pennington from flooding, as well as enhancing habitats.
EA Hurst Spit to Lymington senior project advisor, Rhian Edwards, said the new strategy was being developed to address aging seas defences, loss of habitat and climate change.
As part of the strategy, EA must model the likely impacts if no action was taken – which include the ‘overtopping’ OF Hurst Spit this year; the failure of aging sea defences by the 2030s; the loss of salt marshes in Keyhaven by 2038 and the loss of salt marshes at Lymington by 2046.
She warned: “We believe there are only 15 to 20 years left in a lot of the sea defences along this stretch of coastline, and if we were to stop undertaking the maintenance you would see a deterioration over that period of time.
“Ultimately, within 100 years you will start to see sea level rises of over a metre in this area, which will be very significant if we don’t start to mitigate that.”
Key to the strategy will also be enhancing and improving the natural environment and promoting carbon reduction through habitat creation.
Proposals in the most simplistic form are made up of two options – hold the line and managed re-alignment.
As part of the hold the line strategy, taller and wider seas defences would be required. Managed retreat means sea defences would be pushed back to allow water in – while still protecting homes from flooding.
Ms Edwards said it was likely a combination of both strategies would be used.
Turning to the Lymington Quay area, she said managed realignment would not be considered for urban areas and the location of the current sea wall would not change.
Maintaining the wall at the current level now and building it up to a greater height in future years was estimated to cost between £39m and £64m.
Describing the costs as “eye watering”, she said: “What these figure show is the reality of investment needed for this stretch of coastline going forward.”
Turning to Hurst Spit, it was suggested one option would be to allow the shingle bank to roll back and become slightly lower and flatter, with periods of over washing anticipated. This scheme would cost between £13m and £16m.
The other “aspirational” option would be to maintain Hurst Spit and eventually make it higher at a cost of £43m-£52m.
A historic landfill site between Jetty-Butts and Oxey-Pennington was also discussed, and Ms Edwards said it would be necessary to ensure it could not erode and leak out into the marine environment.
She said in this area a hold the line strategy could be adopted with sea defences maintained, and ultimately built up at a cost of £30m-£36m.
Another approach would involve the managed realignment of sea defences in this location to enable the creation of new salt marshes, costing between £139m and £170m
The Hurst Spit to Lymington Strategy is being led by the EA, in partnership with New Forest District Council, Hampshire County Council, Natural England and JBA Consulting.
A series of public exhibitions are planned as part of the strategy, taking place at Lymington United Reform Church on Wednesday (21st June) from 10am to 4pm; at Lymington Community Centre on Friday 30th June from 2pm to 7pm and Saturday 1st July from 10am to 1pm; and at All Saints Church in Milford on Wednesday 12th July from 2pm to 7pm.
To find out more visit hurstspit2lymington.co.uk
