Most of us understand the triple, interlinked threats we face from the climate crisis, biodiversity crisis and nature crisis. With 15 per cent of our flora and fauna at risk of extinction, we must halt the decline in UK biodiversity.
Extreme weather is bringing droughts, wildfires and flooding. Experts increasingly see working with nature as a win-win to tackle these human-induced, often interconnected, problems. Nature-based solutions (NBS) can mitigate the impact of these threats and help to reverse them.
To strive for NBS is a global priority. To the extent, NBS was included as a topic at COP26 in a coalition session, and for the first time in the COP27 cover decision. The International Union for Conservation of Nature (IUCN) defines NBS as “actions to protect, sustainably manage and restore natural and modified ecosystems that address societal challenges effectively and adaptively, simultaneously benefiting people and nature”.
NBS includes natural flood management (NFM), green infrastructure, sustainable drainage systems (SuDS), nature-based flood management (NBFM) and natural water-retention measures (NWRMs).
Pressures from population growth, urban creep, more intensive farming and climate change have eroded catchments’ natural abilities to manage hazards. This can cause more flooding, droughts, wildfires and pollution.
Recent changes in policy and practice support catchment-scale approaches to restore and emulate natural processes across landscapes and coasts. It’s a shift away from grey methods, engineered to solve isolated problems without multiple co-benefits.
Some see NBS as something new; that’s not true. It long predates Victorian industrialisation and the intensification in 1940-1970 of land drainage, holding water in the landscape for multiple community benefits.
Back in 4,000BC, the early Mesopotamians developed irrigation systems to flood fields and replenish farmland silt and nutrients as the Tigris and Euphrates refilled their floodplains, holding water in the landscape for multiple, long-term benefits.
Six thousand years on, pressures from modern infrastructure, population growth and urbanisation and our inherited, creaking Victorian infrastructure make many people nervous about restoring natural processes.
SuDS projects have made great strides making sustainable drainage methods common practice, especially in the urban landscape. Since storms Desmond, Eva and Frank brought extensive flooding to Cumbria in 2015/2016, there has also been investment in – and review of – 60 NFM catchment-scale projects, with research from multiple NERC-funded programmes.
Recent UK-wide policies and strategies have encouraged public and private investment in NBS. The Environment Act positions NBS to underpin nature’s recovery – particularly part six of the act that enshrines biodiversity net gain in the planning system – and species-conservation strategies and local nature-recovery strategies.
For the rural environment, the 2020 Agricultural Act provides powers to implement new approaches to farm payments and land management as we leave the European Union’s Common Agricultural Policy. This includes funding farmers for public good through Environmental Land-Management Schemes (ELMS).
These schemes aim to achieve Defra’s 25-Year Environment Plan and the UK commitment to net-zero emissions by 2050. ELMS includes NBS ranging from minor changes to soil management to more ambitious, landscape-scale restoration.
The 2020-2026 Environment Agency Flood and Coastal Erosion Risk Management (FCERM) Strategy for England sets the ambitious vision of “a nation ready for, and resilient to, flooding and coastal change – today, tomorrow and to the year 2100”.
It encourages flood-risk management authorities to use NBS and to invest in flood and coastal resilience that also improves the environment. This objective builds on lessons from the £15 million NFM programme, driving several actions to expand and mainstream NBS.
In the built environment, Defra plans to implement Schedule Three of the Flood and Water Management Act 2010 in England during 2024. Wales implemented it in 2019. Schedule Three requires most new developments to secure approval from SuDS Approval Body (SAB) the unitary/county council.
Schedule Three removes developers’ automatic right to connect surface water to sewers, requiring the SAB to approve the drainage system. It aims to reduce risk of flooding, storm-overflow discharges and pollution from urban surface-water runoff and to boost biodiversity, amenity, and carbon.
Regarding strategies, it is also important to recognise the need to work across urban and rural land uses to scale up.
Planning strategies led or shaped by the Environment Agency – River-Basin Management Plans (RBMPs), Flood-Risk Management Plans (FRMPs), Water Resource Management Plans (WRMPs) and, most recently, DWMPs – open opportunities to think more holistically about how to apply NBS, to be strategic and prioritise solutions that deliver multiple benefits.
Top tips to deliver effective nature-based solutions
The evidence suggests we need to:
NBS works best at a scale to suit the catchment’s particular problems. Often more variety and density of NBS brings greatest benefits. Thinking in isolation is a barrier; more may benefit from an integrated, partnership-led approach.
Use and share your catchment’s best available evidence to understand critical problems. They may be interlinked. That understanding then highlights constraints and risks for NBS, such as infiltrating pollutants to areas of groundwater protection or enhanced backwater flood risk from slowing the flow downstream from one community to protect another.
Delivering best-value, partnership-funded NBS demands engagement. This recognises that you may not have all the answers – that you need help, at local level, from land managers, environmental NGOs and local action groups whose knowledge may not lie in datasets and geospatial layers.
Working with the Environment Agency, Lead Local Flood Authorities, water companies, internal drainage boards, Natural England, the Forestry Commission, universities and others boosts your technical knowledge of the catchment.
These bodies may have their own models, datasets and knowledge from other, similar projects. Building partnerships clarifies catchment solutions that may not be nature-based but point to the most workable solutions.
Successful programmes empower local communities and groups to own their problems; to invest in and co-develop solutions as partners. These local partners are often best placed to gather evidence of NBS performance and to manage and maintain these systems.
It is often easier to justify tried-and-tested grey solutions. We will always need them – but we must be bolder, trying green over grey, or integrating them; say, using NBS upstream to ease pressure on a traditional concrete flood-management scheme. Understanding that grey is not the only answer can develop and build skills in the supply chain to deliver NBS for multiple benefits.
And finally, remember:
Each NBS project is multi-faceted. One size does not fit all. Each requires engagement at different stages with different stakeholders, which takes time and effort.
Early stages may expose gaps in evidence on NBS performance. Despite hundreds of international pilots and several evidence reviews, there are always questions specific to your catchment and proposed solution.
Tap your partners’ support – use modelling and monitoring to develop your evidence base, to justify using NBS. It takes continuous monitoring to understand whole-life performance, including NBS maintenance needs and changing benefits.
But by collaborating and being brave, we can stimulate economic, environmental, and social growth – and make the world a nicer place to live.
Dr Tom Lavers is a technical lead on drainage and wastewater management plans at the Environment Agency. Jon Hollis MCIWEM is a programme manager at the Environment Agency, working to make NFM mainstream
This story was first published in The Environment magazine in May 2023
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