“Portsmouth is at the forefront of the global climate emergency”- How will coastal defences protect the city from severe flooding?
Portsmouth could be partly underwater in 30 years. Buildings could be submerged, impacting the lives of many and destroying fragile habitats of innocent wildlife.
Climate central, an organisation that reports climate science has predicted that parts of Portsmouth will be underwater by 2050. Although this is just a warning of what could happen, the reality is that the rising sea levels and the impact of climate change isn’t getting better.
The effects of climate change have devastated many communities around the world, from draughts to deadly storms and flooding. It has been predicted that climate change will increase the intensity of storms and major flooding in the UK, especially coastal cities such as Portsmouth.
The debate of how to combat climate change has been in conversation for years, so what do we need to do now to protect the historical features of our seafront?
Dr Jonathan Potts from the Portsmouth school of Environment, Geography and Geosciences, said that the world is facing environmental challenges such as sea level rises and Portsmouth will suffer greatly from it without defences.
He said: “Portsmouth is at the forefront of the global climate emergency because it is the UK’s only island city. Portsmouth is surrounded by water and it is the second most densely populated city in Britain.”
As well as working at the University, Dr Potts also provides research background in coastal defence. He added: “Portsmouth needs to be defended with engineering-based defences because of the significant infrastructure. What the Southsea Coastal Scheme is doing really well is that they are integrating human elements with physical elements.
“They are providing public access, recreation and are generally not disrupting the public from using the shoreline, whilst providing state of the art protection.”
The Southsea Coastal Scheme started constructing new coastal defences in September 2020 and aims to finish in 2028, in hopes that it will reduce the impact of major flooding for the next 100 years. They also aim to mitigate any damages done to natural habitats in the sea, and take in consideration the history of the area such as the Southsea Castle. Throughout the process of creating these defences, having the public involved and considering how the area will be used by locals has given them a positive reputation whilst most of the seafront is closed for construction.
Worth more than £160m, this scheme is the largest authority-led coastal defences project in the UK.
Although this plan will keep major flooding from affecting our coastline, there still needs to be a viable plan in place to reduce the impact of climate change around the world. According to Climate Central’s previous research, rising sea levels could affect all regions of the UK within the next 10 years (source: Portsmouth News).
Rena Wiethaupt, the engagement and communications officer at the Southsea Coastal Scheme, said that recovering from a major flood in Southsea could cost up to £950 million.
“Climate change is resulting in sea levels rising and harsher weather conditions along the seafront. The storms basically destroyed the old defences, so the new ones will be stronger, more modern and higher.
“The design will withstand a 1 in 200 year event. Think of the worst case storm with a high sea level rise- there is a possibility of 0.5% every year. It could happen this year, could be next year, or in 200 years. These defences are supposed to last for 100 years.”
Neil Dorling, the senior project manager for the coastal defences contractor VSBW, said it has taken 10 years to get to the current stage of building and started onsite in September 2020.
“There is a lot of concrete being used in the hard structures. We are also using rocks and limestone. We are creating timber seating around the area and we are also renewing the lighting.
“The recycled material we are using is crushed concrete that we have created from breaking out the existing structures.”
Despite these new defences being effective in protecting our homes, this could have a negative impact on natural habitats.
Rena explained that building hard structures where natural life would move towards is called a “coastal squeeze”. She added: “The defences don’t help nature, it’s quite the opposite. But we know we have to do something to protect our buildings. There is a strip of flora and fauna that will suffer from it, so in order to mitigate that, there are a lot of environmental enhancements. Our tidal pools are porous, they mimic what some rocks have on the surface. The tide comes in and the water stays in there.
“North Portsea is building a wall with crevices in it. When the sea goes in and out, life can continue to grow on the wall. Because of the coastal squeeze we cannot create their natural habitat.”
Although major storms are inevitable due to climate change, it is hoped that having new, state-of-the-art coastal defences will mitigate damages to the city, and mitigate the damage to natural life in the water. These defences may save lives, and the city will be alive and well for many more years to come.
