Widespread flooding last Christmas should have pushed debates over how to ensure the UK’s landscapes are better able to withstand climatic extremes to the top of the political agenda. As the climate changes, and floods and droughts become more frequent, time is running out for us to build more resilient landscapes before they are damaged beyond repair. Yet the main question circling Westminster in the aftermath of the floods was more binary: to dredge or not to dredge?
Dredging began on the Somerset Levels in the spring and the government breathed easier. Under the weight of public and media pressure for affirmative, robust action, the sight of armies of diggers scooping up tonnes of silt from the riverbeds was just the political ticket. Previous calls by then Environment Secretary Owen Paterson to “do more to hold water back, way back in the hills” faded to the periphery.
Yet, dredging is a palliative treatment. If we make more space in our rivers for water then we are making more space for sediment too. As journalist George Monbiot has said: “…it’s like trying to empty the bath while the taps are running.” The only long-term cure is to reduce soil erosion and therefore sediment deposition in channels at source. If we fail to do this then we will be dredging for decades to come, as well as losing the very resource – the topsoil – that we need to produce food. We will all be paying for it, twice.
The government recently announced £2.3bn in flood defence spending. This still ignores the fact that flooding can be mitigated if we change the way we treat the soil and farm the land. If we understand the connection between damaged landscapes, where soils are compacted, drained and easily eroded, and heavy silting within flood-prone rivers, then we can address the real source of the problem. The logic is straightforward: increase a landscape’s capacity to store water during heavy rainfall and you decrease the amount of water and soil running into rivers.
The benefits of strategic land management go beyond flood prevention. In times of drought we need the land to hold onto water. Restoring the hydrological function means less water pollution, better biodiversity protection and an increase in the soil’s ability to store carbon.
Chairman of the Environment Agency (EA) Lord Smith has spoken of the need for a “much more comprehensive solution” to reduce flood risk. It is time to turn abstract terms into practical policy measures: a new, holistic strategy for land management across the UK that does not fall into the trap of improving resilience in one area to the detriment of all others.
It is single-issue policymaking that has landed us with a legacy of damage to the landscape that we are now paying for. Take the one-track focus on boosting food production since industrialisation. Thousands of miles of drainage ditches were dug across the UK’s moorland to ‘improve’ the soil; a strategy that served to increase water flows downstream and cause water quality to deteriorate. Under Defra’s current ‘Sustainable Intensification’ program, we cannot allow mistakes to be repeated. Intensification of farming must only occur where it will not cause costly damage to the environment.
It is not too late to reverse the damage. On Exmoor, the Mires-on-the Moors project, a partnership between South West Water (SWW), EA, Exmoor National Park Authority and Natural England, is working to block moorland drainage ditches as part of a programme to restore the hydrological function of 2,000 hectares of peat bogs.
Tasked with evaluating the success of the scheme, the preliminary results from our trials at the
University of Exeter, funded by the Natural Environment Research Council and SWW, are game changing. Restoration allowed the moorland to store two thirds more rainfall, significantly reducing the amount of water entering the River Exe over the winter months, and acting as a crucial buffer against downstream flooding. Water quality is up too, which both cuts the cost of water treatment and increases the land’s carbon retention.
Soil erosion from agricultural land poses a huge problem. Unfathomably, maize farming is free from government regulation but an
academic studypublished last year found that three quarters of the maize fields in the South West contribute to flooding. The most sensible approach is to regulate the cultivation of maize, kale and winter cereal crops on steep slopes, particularly in areas most prone to soil erosion and flooding.
Farmers should be incentivised to change their behaviour and recognise the impact downstream of leaving vulnerable soils bare, which increases soil erosion and water runoff. Diversifying farmers’ income is key.
In a project to restore lowland grasslands in Devon - Culm grasslands - with Devon Wildlife Trust and EA, we found restored grasslands could store up to five times as much water as intensively farmed grasslands, attenuating downstream flooding, and storing twice the amount of soil carbon. Water quality was vastly improved too. The project demonstrated so many hidden benefits of farming the grasslands less intensively that any loss of income to farmers could certainly be offset by diversification of income from water companies, tourism, carbon trading or agri-environment schemes that recognise the environmental benefits.
We need high-level political support for a coordinated national programme of landscape restoration. The cost to taxpayers or the Treasury would be minimal and the saving would be realised for generations, as ‘downstream spending’ on dredging or flood defence schemes becomes less necessary due to ‘upstream’ management changes. However, such change requires a departure from the current, fragmented form of environmental policymaking where one department is preoccupied with flood resilience, another with water quality and another with cutting carbon emissions. It requires holistic policy-making with real, long-term vision.
Richard Brazier is Associate Professor of Earth Surface Processes at the
University of Exeter.