SUMMARY

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Floodplains are the most under-appreciated assets in our natural capital arsenal to fight climate change. For decades we've treated them badly as second rate farmland, we have flattened, ploughed, drained, and built on them.  With pressure on more housing, we are now increasingly paving over them, storing up trouble that will lead to evermore frequent catastrophic floods.

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But we are discovering that in their natural state they can provide the flood defence infrastructure and clean up our rivers, without putting up water bills. They do as good as a job as built infrastructure for 1-3% of the cost of all that concrete, and keep on going for years to come, and for free.

 

Floodplains are nature's Swiss army knife capable of providing a range of benefits such as slowing down flood waters, storing carbon, cleaning water, sheltering wildlife even providing a touch of beauty. The paradox is often that the best management strategy is often to do less. A series of planned interventions can help nature kick start and connect floodplains to their river courses often where man has intervened in previous centuries to do the opposite, then it is a case of letting nature go to work and they will outperform man made systems for protecting homes, landscapes and our critical communication and power infrastructure. 

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Why Floodplains Matter

• Scale: About 1.6 million hectares of England & Wales are floodplains.

• Habitat Loss: Only ~3,000 ha of species-rich floodplain meadow remains.

• Imbalance: ~70% of floodplains are intensively farmed, while only 11% remain as semi-natural habitat.

• Risk: This imbalance reduces resilience to flooding, drought, and biodiversity decline.

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Floodplains as Natural Capital

Natural capital is the stock of natural assets (soil, water, habitats, species) that generate ecosystem services such as:

 

• Water purification

• Floodwater storage

• Carbon sequestration

• Pollination & biodiversity support

• Recreation & cultural value

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Accounting for these services gives land managers and policymakers the evidence to restore and protect floodplains effectively.

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Benefits by Land Use

• Semi-natural habitats (floodplain grasslands, wetlands, woodlands) deliver multiple services at once, including flood storage, biodiversity, carbon capture, recreation.

• Intensively farmed land produces food but provides fewer regulating and cultural services, and suffers higher flood damage costs.

• There are emerging schemes that are blending a regenerative agricultural approach with delivering a range of ecosystem services on flood plains, there are also early indications that if we can get the regenerative farming model working combined with payment for ecosystem services then there is a route to improved profitability for the farmers in these river valleys.

• Economic value: Flood damage costs can exceed £4,800/ha on horticultural land vs. just £80-160/ha on species-rich grasslands.

 

Case Studies

These case studies are mentioned in the Open University Report that we reference at the bottom of the page.

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• Chimney Meadows NNR: Restoring farmland to floodplain meadow delivered £7m extra benefits over 30 years (a 592% uplift in natural capital value).

• North Meadow NNR (Wiltshire): Total ecosystem services worth £1.55m, compared to £925k for farming alone (a 68% gain).

• Nene Valley Nature Improvement Area: Mapping showed restored habitats delivered £2,639/ha of benefits vs. £1,769/ha for intensive use—especially through recreation and cultural value.

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Management Recommendations

• Reduce fertiliser and chemical inputs.

• Time hay harvests and manage water levels to boost biodiversity.

• Reconnect rivers with floodplains to increase resilience.

• Develop floodplain-specific agri-environment options in UK farm policy.

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Where Nature Equity Limited is working to improve the evidence in NCA for Flooplains

The report highlights the need for improved data, integrated approach to ecological and financial information, new business models and leverage the revolution in monitoring and earth observation sources and the power of AI. Natural Equity is working on the following:

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We are working on providing digital models for whole catchment areas so that the upstream and downstream behaviour of flooding can be better understood, and flood models should the flow of the water over the topology of the landscape. We can model the hills, valleys and flow channels in the landscape more realistically than ever before using Lidar data. Our big data model approach also provides accurate prediction of flooding in large areas, showing extent, depth and economic impact of the flooding. 

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Our natural capital model library provides a range of economic models to support local data for the full range of ecosystem benefits including farming, flood peak flow reduction, water quality improvement, biodiversity uplift, BNG, as well recreational and cultural value. 

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We are also working on using the same digital flow model to show how restoration affects flood management.

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Key Takeaway

Investing in floodplain restoration yields greater long-term value than intensive agriculture as it plays in role in protecting people, nature, and the economy. By recognising floodplains as natural capital, landowners and policymakers can unlock multiple public benefits.

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📖 Source & Licence

 

This summary is adapted and augmented from:

Valuing Nature Programme (2018). The Natural Capital of Floodplains: management, protection and restoration to deliver greater benefits. Synthesis Report VNP09.

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The original report can be found at: https://oro.open.ac.uk/82789/

 

This work is licensed under a Creative Commons Attribution-ShareAlike 4.0 International Licence (CC BY-SA 4.0). You are free to share and adapt the material with attribution, provided adaptations are distributed under the same licence.

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