Are nature-based solutions the answer for our transport networks?
As a highways service offering nature-based solutions are still in its early stages. To fully make use of natural resources more research is required.
The effects of climate change are clear, and as an industry we already know that unless we take urgent action the impacts of extreme weather, flooding and rising temperatures will lead to widespread damage to infrastructure, with our transport networks being particularly at risk.
This will be hugely disruptive for people and businesses, so the question is how we grow and move the highways sector forward with these concerns in mind. Highways have also long been under the environmental spotlight because of the contribution of vehicles to rising levels of carbon emissions and climate change, and the building of roads through our countryside.
In 2019, the UK became the first major economy to pass laws to end its contribution to global warming, requiring the country to bring greenhouse gas emissions down to net zero by 2050. The 25 Year Environment Plan published in 2018 also sets out ambitious goals for improving the environment and enhancing biodiversity.
Highways England is already taking steps to address these issues. Its Climate Change Adaptation Strategy and Framework provides the basis for identifying preferred options to deal with the assessed climate risks and opportunities, while its Environment Strategy sets out a vision for “a strategic road network working more harmoniously with its surroundings to deliver an improved environment.” To support this agenda, Highways England has committed to reforming its Environment and Wellbeing Fund by 2022-2023, channelling designated funding towards making improvements that deliver lasting benefits.
Meeting national and global climate, carbon and sustainability goals requires co-ordinated action alongside policy changes, technical innovation and a move to a greener economy. We believe that nature has a vital role to play. ‘Nature-based solutions’ can enhance natural capital and ecosystems, complementing or offsetting traditional infrastructure to help address impacts from climate change and biodiversity loss while delivering multifaceted co-benefits.
Stopping the flood
Flooding is one of the big climate risks for our road networks and natural flood management (NFM) approaches are a good example of how actioning a nature-based solution, rather than a grey infrastructure response can minimise environmental impact and enhance biodiversity.
For example, woodland creation schemes intercept overland flow of water and encourage infiltration and storage within the soil, trapping floodwaters before they can reach the roadside.
The integration of wetland and grassland habitat and reedbeds into the landscape design as part of our work on the Bexhill to Hastings Link Road provided valuable flood attenuation. It also reduced downstream flood risk, while delivering biodiversity net gain through new habitat for a wide range of species, including wintering and breeding birds and invertebrates.
NFM schemes are often cheaper and quicker to implement than traditional flood management techniques but can still be used in conjunction with concrete flood barriers, for example, to give highways infrastructure better protection. In 2018, the UK Environment Agency compiled an evidence-base around working with natural processes, finding that ‘using the right combination of measures in the right places can help to slow flood peaks and reduce the depth and duration of flooding’.
The creation of woodland and grassland areas can also lower the footprint of project works and help reach sustainability goals. NFM techniques reduce the reliance on carbon-intensive materials such as concrete and steel. New woodland and grassland will grow, eventually removing carbon from the atmosphere through sequestration, while creating new habitats for wildlife that will increase the area’s biodiversity.
People benefit too
From a purely highways perspective, human wellbeing can be positively impacted by nature-based solutions. Although the efficacy of using plants as a screen to mask the noise from roads is disputed, research has shown that people’s perception of noise is dramatically lowered when they can see woodland and other plant life along the roadside.
Bringing nature to the fore at the design stage also enables hitherto marginal or unrealised benefits to local communities to be enhanced, adding to the co-benefits and overall sustainability of a road scheme. As part of our work on the A3 Hindhead Scheme, a road notorious for congestion and its impact on nearby environmentally sensitive sites, we were able to integrate a range of environmental measures and design features that allowed for the re-creation of a natural landscape form, regeneration of heathland habitat and a range of community benefits, such as safe cycleways, amenity and waking routes and improved tranquillity of the area.
A greener future
Nature-based solutions span far beyond NFM, but as a highways service offering it’s still in its early stages. To fully make use of natural resources more research is required.
After all, every project is different, and while Highways England certainly has the land-capital required to make use of more nature-based solutions, each area of works would have to be carefully evaluated to ensure the right kind of carbon-mitigating flora grows on the land the team has access to.
Nature-based solutions are certainly an effective solution to the sequestration of emissions, but in many cases the CO2-removing plant life can take several years, even decades to grow to a point of significant effectiveness, when in reality we may require a more immediate response.
However, we are primed to help answer these pressing questions. We have been helping to drive the development of carbon calculator tools through implementation of PAS 2080 standards for CO2 management for infrastructure and have been working closely with the UK Environment Agency to deliver carbon-calculating methods for NFM schemes. We have also in recent years developed the Moata Carbon Portal, the first carbon calculator capable of measuring the capital and operational carbon footprints of building information modelling (BIM) designed assets.
We have decades of experience across a broad cross section of relevant sectors, including highways, environmental works, flood management, and the built environment, and we are confident that by increasingly embracing natural solutions, the highways sector can experience dramatic cost-savings – and contribute to the global and national net-zero agenda.