Climate Change: managing flood risk, water quality and tidal energy: letter from Marg Coles to Angela Eagle MP

 

Docks along the Mersey 

 

My friend Marg has sent the letter below to her M.P. and whilst it it refers to the River Mersey, the names within our river catchment could just as easily be substituted (Thames, Hogsmill, Wandle, Queens Promenade, Teddington Lock etc.). Lack of preparation and rising water levels in the Thames, are becoming an increasingly urgent concern, yet preparation has lagged behind the pace of change. More frequent and intense rainfall, higher tides, and climate-driven sea-level rise are putting additional pressure on aging flood-defence systems. 

“From 2035, sea level rise and changes to the Thames Barrier operation will result in higher water levels in the River Thames. In areas between Richmond and Sunbury, these increases could range from over one metre to as little as a few centimetres during frequent flood events that we expect to see most winters. Sea level rise will progressively increase flood levels in West London throughout the rest of the century.”

Read in detail about why this is happening, and how the West London Communities Project is seeking to increase our defences against flooding, in this report from the Environment Agency:

https://engageenvironmentagency.uk.engagementhq.com/west-london-communities-project

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While authorities have acknowledged the risks, investment and long-term planning have not kept up with the scale of the threat, leaving vulnerable communities and key infrastructure exposed. Without more decisive action, the region may face preventable disruptions and damage in the years ahead where are the borough's flood defences? Here’s a start by TFL and Thames Water at Tolworth roundabout.

Counties where serious flooding has occurred during the last two years, including current flooding in Monmouth, where the river Monmow has burst its banks. The table includes the named storms and dates.

OpenAI (2025). ChatGPT (GPT-5.1). Generated mapping support.

Storm Claudia and her effects made it into the national headlines – but mostly, local and regional floods now seem too mundane to attract that kind of attention. Eleven days ago, Cumbria saw submerged roads, blocked drains and over 250 flood-related problems reported to the relevant councils. Railway lines in Cornwall were submerged; in Carmarthen, in west Wales, there were reports of the worst floods in living memory. But beyond the areas affected, who heard about these stories? Such comparatively small events, it seems, are now only to be expected.https://www.theguardian.com/commentisfree/2025/nov/16/uk-flood-water-wales-cornwall-rescue 

Marg’s also letter reminds of the Ham Hydro project Teddington Lock 2010-2016,  a sterling community-led effort to generate renewable energy from the Thames. This ultimately did not move forward after years of planning, consultation and sheer hard graft from those involved. the scheme faced a combination of technical challenges, regulatory hurdles, and concerns about noise impacts. These issues made it difficult to secure the support and approvals needed and it is hoped that a more positive regulatory framework exists today.


Dear MP Angela Eagle,

I am concerned about the future of the River Mersey and its surroundings, which include Wallasey Promenade where I live, not for myself, as I am nearly 80 yrs of age, but for those who will face dealing with the effects of climate change in future. Money will need to be found to mount flood defences due to rising sea levels (amongst other effects). We are getting very little information concerning the proposed Mersey tidal barrage, and how it would affect internationally protected wildlife areas, or the fish species in the Mersey and its feeder rivers.
How long it would take to build? What changes will have taken place during construction? Will the time it takes to build the barrage mean it is not going to be of any help before it is too late? What other demands on our financial resources will be called upon to prevent widespread flooding, including expected flooding of Liverpool Docks? Would a flood defence such as that on the Thames be more useful? I would be grateful for your views. The following has been gleaned from the internet:

By 2050, the River Mersey and its surrounding areas are predicted to face significant changes due to climate change, including major flood risks from rising sea levels, particularly in coastal and low-lying inland areas, and ongoing efforts to improve water quality and potentially develop tidal power.

Environmental and Climate Impacts Increased Flood Risk: Climate Central and the Environment Agency predict a significant increase in flood risk. Large parts of Merseyside, including Sefton, North and West Wirral, Widnes, and Warrington, could be at risk of annual coastal flooding or become permanently submerged if no further action is taken to cut emissions.
 

Sea Level Rise: Rising sea levels, driven by melting ice sheets and the expansion of warming seawater, will cause the coastline to change dramatically. Areas such as Hoylake, Meols, and parts of the Liverpool docklands are at high risk.
 

River Flow Changes: Climate models suggest potential reductions in river flows during summer months, alongside increased risks of river flooding during wetter winters due to heavier rainfall.
Water Quality and Pollution: Despite decades of work to clean the river, concerns remain about future water quality. A proposed Mersey tidal barrage project, while offering flood defense benefits, could potentially trap nutrients and sediment, risking the estuary becoming a "green, fetid lake" and damaging internationally important habitats.
 

Habitat and Wildlife Damage: The Mersey Estuary is a vital wetland for birds and marine life. Rising sea levels and potential large-scale infrastructure projects (like a barrage) could damage or destroy irreplaceable intertidal mudflats and saltmarshes, threatening the diversity and abundance of fish species. 

Planning and Mitigation EffortsTidal Power Project: The Liverpool City Region Combined Authority is exploring the Mersey Tidal Power project, which aims to use tidal range technology to generate low-carbon energy. Proponents argue it could help manage long-term environmental issues, including sea-level rise effects, but environmental groups like the RSPB are deeply skeptical due to potential ecological damage.
 

Flood Management Plans: The Environment Agency and local authorities are developing flood management plans and strategies to address the increased flood risk, including potential relocation of properties in high-risk areas where building new defenses is not feasible.
 

Water Quality Targets: Plans are in place to make the River Mersey sewage-free by 2030, a decade earlier than previous targets, to continue the progress made in improving the river's health.
 

Green Infrastructure: Projects like the Mersey Forests Green Streets initiative are using urban tree cover and other green infrastructure to help mitigate climate impacts like urban heating and surface water runoff.
 

The Mersey of 2050 will be a river system actively grappling with the unavoidable impacts of climate change, with its future landscape heavily dependent on the success of significant flood mitigation and environmental management projects. predicted to face significant changes due to climate change, including major flood risks from rising sea levels, particularly in coastal and low-lying inland areas, and ongoing efforts to improve water quality and potentially develop tidal power.

see also

catchment-based-approach 2016

sustainable-urban-drainage 2021