How nature can help us hold back the floods

How nature can help us hold back the floods

As flooding becomes more frequent and more extreme, we can't manage floods as we did in the past. We need a new approach - and nature can be part of the solution.

Flooding is returning to the news, after a matter of weeks, as communities across the UK are affected by floods which damage homes, destroy livelihoods and disrupt lives for months or even years.

In the past we have largely been able to cope with floods by engineering our way out of them, straightening river channels and building higher flood walls to funnel water quickly out to sea.

But as our weather patterns have changed and we experience more intensive rainfall we are finding that these approaches aren’t enough. The rain falling on hills and uplands has to go somewhere, so it flows overland and in rivers, to bottlenecks or low-lying areas downstream where it causes floods. Generally, it is our towns, cities and productive farmlands that are the casualty.

What's the answer?

We need to find a new solution. Where we can’t move flood waters on quickly, we can look to hold them back instead. Storing or ‘slowing the flow’ of flood waters in upstream areas can help to delay or reduce flood peaks downstream as water is prevented from rushing headlong into towns and cities.

Wildlife Trusts are leading the way in developing these new solutions:

  • Gloucestershire Wildlife Trust has created 'leaky dams', which trap water behind them and force it to slowy drain through, once the risk of flooding has passed
  • Dams are being created by beavers, reintroduced through several Wildlife Trust-led projects, having the same impact as leaky dams
  • In upland habitats, water can be held back on the land before it reaches river systems - Cumbria Wildlife Trust and Yorkshire Wildlife Trust are working to block historic drainage ditches, known as 'grips', cut into moorland to dry the land for agriculture
  • Shallow scrapes are being created, which collect and hold water, allowing it to soak in
  • In the Peak District, Cheshire Wildlife Trust and partners have placed 'log diverters' in channels encouraging water out onto the floodplain where it can be temporarily stored. Water either soaks in or returns to the channel when levels subside, depending on the nature of the soil and underlying geology
  • Our landscape is far less able to hold water than it was in the past – much of it is built on or dedicated to intensive agriculture, limiting permeability and meaning water runs off the land rather than being absorbed. Shropshire Wildlife Trust’s Slow the Flow Project works with farmers to aerate fields, improving infiltration and reducing pollution from runoff
  • Through the Sussex Flow Initiative, Sussex Wildlife Trust has planted hedgerows and woodland to intercept rainfall and surface run-off, increasing water infiltration into the soil
  • Managing natural habitats so they can store or absorb water is important too: Cambridgeshire’s Great Fen provides water storage that protects surrounding farmland and communities from flooding, and the Wildlife Trust for Bedfordshire, Cambridgeshire & Northamptonshire are working with farmers to test ways in which the fenland can be sustainably farmed.

Natural habitats are important to help us manage water, but these areas of land alone aren’t enough. The majority of the countryside – 70% – is farmed, so the farmed landscape must also play its part. Besides helping to prevent flooding there are further business benefits to farmland better absorbing water: soils are not so readily washed away during downpours, taking with them expensive fertilisers and pesticides; and in dry periods, crops are protected from drought by soils that are able to cling on to moisture. Both are important attributes in our increasingly erratic climate. A key way to help soil hold water is to increase its organic content (i.e. mineral and nutrient content), as this rich material acts like a sponge. This can be achieved by adding organic material like manure rather than chemical fertilisers, and by reducing the amount and depth of ploughing so that soil structure remains undisturbed. For some farmers these changes make business sense, whilst for others financial incentives may be required to support the move to different, less intensive forms of management. 

We need a rethink on how we manage excess water in our towns, cities and rural areas, as managing floods isn’t just about managing water, it’s also about managing land.

These techniques are showing that we need a rethink on how we manage excess water in our towns, cities and rural areas, as managing floods isn’t just about managing water, it’s also about managing land. The right incentives need to be in place to support farmers and land managers in making changes that can help to protect our society from the damaging effects of flooding. There is a role here for Government too as it creates new Environmental Land Management Schemes, but also for water companies who have an interest in the quality and quantity of water in our landscape, and perhaps even for the insurance industry, as they start to consider flood preparedness and prevention. For the impact of these changes to be long term and of benefit to us all, it is important we take a holistic approach - working in partnership to achieve a landscape better for wildlife and people.