Seaside spend

Senior Engineer, Vicki Berg-Holdo, looks at the difficult choices ahead for allocation of coastal protection funds.

Two articles caught my attention when browsing a published feature on flood risk.  ‘Adapt or Drown’ by Rob Hakimiam and ‘Beside the Seaside’ by Claire Smith (New Civil Engineer, August 2022) explored measures designed to protect two very different coastal towns from flooding.  The first is Looe in Cornwall and the second is Southsea in Portsmouth, Hampshire.  When considering both schemes, it might be helpful to compare proposals designed to address the impact of climate change on coastal areas, with measures to curb flooding of inland areas.

Flooding of inland areas can be due to excessive rainfall and overdevelopment, if robust mitigation measures are not adopted.  The problem is only likely to intensify further due to climate change. Much has already been debated about these particular causes of flooding, and planning guidance deals with the issue pragmatically.  Each new development must therefore play its part to reduce the risk of flooding to downstream properties.

Not so well managed, perhaps, is the flood risk to coastal areas.  This can be the result of a combination of:

• sea level rise due to climate change, which will produce higher tides and elevations that will restrict the drainage of land into rivers as they approach estuaries.
• increased rainfall due to climate change, which will add to river flows and create serious flooding when high flows meet high sea levels at river estuaries.

The NCE articles set out coastal flood protection schemes for two very different towns and serve to highlight the difficulty in justifying the high costs of sea defences.

Seasonable fluctuations

Looe is a small town which, during the tourist season, sees an expansion of the population and increased economic activity.  The cost of proposed sea defences to protect the town is around £100m.

The justification for the scheme’s funding includes a number of what might be considered subjective arguments; the need to preserve an old town, its customs, livelihoods and skills.  It is also important to enable growth and protect the railway station and utilities.  The population to be protected is approximately 5,000 inhabitants.  1,600 jobs would be at stake if the town were to be lost to the perils of the sea.  On paper, using the common flood defence funding criteria, known as National Flood and Coastal Erosion Risk Management (FCERM), this expenditure is unjustifiable. Whilst an admirable aim to preserve the town, it does call into question the criteria for investing in coastal protection.

Common flood defence funding criteria

The work under way at Southsea in Portsmouth is in stark contrast.  Claire Smith has outlined a scheme in which the costs are likely to be of the order of £130m.  However, the population to be protected is around 10,000 people and more than 700 businesses.

Pound for pound, the scheme at Looe would not make sense if the FCERM funding criteria were adopted.  These criteria were traditionally based on the number of properties to be protected. However, does this approach still remain relevant today?  If not, what is the most appropriate alternative?

Southsea has a seasonal tourist population and is a town with significant historical interest.  Looe is a picturesque town, but with limited funds for protecting our coastlines against erosion, hard decisions may need to be made.

Do we act out of emotion or necessity when looking at areas whose flood protection raison d’etre no longer has currency?  And should we take the opportunity to build new development well away from areas at risk of flooding, now and in the future?  These are the questions policy makers and think tanks have been debating.

In Looe, the adaptation policy where old buildings at risk of flooding will not be developed once the use has gone, will need to be implemented.  New buildings will be sited away from vulnerable areas.  The search for safer sites which do not tend to flood is encouraged, when there is a veto on redevelopment of an existing site.  The sequential test within planning guidance – where it can be demonstrated that sites at lower risk of flooding are not available – has never really been taken seriously, but it might just have to move to centre stage.

If you would value a preliminary discussion about the water management issues associated with your development project, call 01483 531300 to speak to an expert.