Climate change - impact on our historic canals and river navigations
Our former industrial canals and river navigations are today playing a hugely important role in society and are enjoying a second golden age.
Our waterway network extends across much of the country, stretching from London to Llangollen, Lancaster and Leeds, passing through hundreds of cities and towns. They are valued by people as never before, providing beauty and wellbeing on the doorstep of millions, forming important wildlife corridors and generating economic prosperity.
Despite their contemporary relevance and reach, our waterways remain one of the oldest critical infrastructure networks in the world and are under growing pressure from climate change. Most of the vital earth structures supporting our man-made waterways include towering embankments, reservoir dams, deep cuttings, hand-built tunnels, thousands of centuries-old culverts which were built before the Victorian age at the time of the French Revolution and the Napoleonic Wars.
Civil engineering and geology were in their infancy and the brilliant canal pioneers developed this new science ‘on the job’ as they responded to the construction challenges that confronted them. There were no standards or previous experience to draw on. They built with admirable skill and we can only envy their brilliance; but the canal network was built for the demands of the late 18th or early 19th centuries with little expectation that its asset life would stretch over 200 years.
Increasing extremes in weather
Increasing extremes in weather patterns are bringing considerable challenges to this ageing infrastructure which the Trust, working with partners and Government, needs to overcome to maintain its resilience and, ultimately, protect public safety. In short, there is an unprecedented scale of expenditure that the Trust, and the nation, has to invest over the next few years to keep pace with the growing risks that this critical heritage infrastructure is experiencing.
We continue to apply our knowledge and resources to keep them safe, and evolve our long-term asset management approach to understand, evaluate and address the potential growing risks of climate change, follow all statutory requirements, and share our work with other key infrastructure owners across the UK to pool knowledge and best practice.
This isn’t something that’s in the distant future; we are already experiencing regular extreme weather events on an unprecedented scale. The damage incurred at Toddbrook Reservoir in July/August 2019 followed the rare combination of two consecutive rare storm events – the first a 1 in 40-year severity storm followed by an even fiercer 1 in 90-year weather event just two days later.
Together the combined effect was described in a report to Stockport Council (lower down the Goyt Valley) as having a 1 in 260-year impact. Exacerbated by design flaws in the 50-year old spillway, this led to extensive damage to the reservoir (costing £20million to manage and repair), and required the urgent evacuation of 1,500 people for a week to manage the risk to public safety.
The damaging effects of the weather
In early 2020, storms Ciara, Dennis and Jorge – three major events within a month or so – collectively caused many £millions of damage across the north of England and to the waterways network specifically. Structures that had once withstood 200+ years of weather were wiped out as though made of straw and sand, as they had been during the devastating floods on Boxing Day 2015 that had ravaged the Calder Valley (and its waterways) just a few years before.
Most recently, in August 2020, our thoughts turned to our counterparts in Scottish Canals when the embankment carrying the Union Canal breached following intense local rainfall and severe flooding, closing the adjacent Edinburgh to Glasgow railway line for several weeks. This was a reminder that much of the nation’s critical infrastructure is interdependent with the very first national infrastructure network, our historic waterways.
While the effects of storms are dramatic, heavy rain isn’t the only climate challenge facing the waterways. Long, dry spells can also be a serious problem causing earth structures to dry out and increase their vulnerability to erosion, especially when followed by intense rainfall when the weather breaks.
Notwithstanding the huge amount of care our professional and dedicated colleagues and volunteers take to inspect, monitor and look after our very old infrastructure, changing climatic patterns mean that it is more exposed than ever before.
Changing the scale of expenditure
We believe that there needs to be a step change in the scale of expenditure on high risk infrastructure – such as reservoirs, culverts, embankments, and cuttings – over the next five years or so, if we are to keep pace with the growing incidence of extreme weather and ensure that these highly-valued waterways remain available for people to enjoy and safe for the communities they run through.
Undertaking the vital work to increase the resilience of our waterways over the next few years will require an additional investment of the order of £200million. Our finances are limited and, as well as stretching our resources considerably, there is an immediate role for Government in supporting the programme of additional spend.
Grant funding for the Trust
The implications and threats of climate change, and tackling this critical issue in years ahead, will also be a factor in the Government’s review of future grant funding for the Trust and our waterways network in England and Wales beyond 2027.
It is vital that levels of grant funding are sustained over the long term to meet the ongoing need for significantly higher infrastructure funding, in addition to ensuring that the everyday enjoyment of the millions who use and value our canals, river and towpaths can continue now and in the future.