Flooded fields in Oxfordshire

Flooded fields

Choosing different crops, building soil organic matter and planting more trees could allow farmers to reduce the risk of nearby rivers from bursting their banks miles downstream, according to an innovative new research project.

CEH researchers are part of the collaborative LANDWISE project led by the University of Reading which will work with farmers, advisors, communities and local authorities across the West Thames area to learn how different land management methods impact on flood risk.

A lot of attention has been given recently to ‘slowing the flow’ within river channels using wood to create leaky barriers. LANDWISE aims to look at the wider landscape and investigate ways to reduce the volume of water entering river channels in the first place, and to ‘slow the flow’ by enabling water to move slowly below the ground surface. This can be done by increasing the amount of water that can be absorbed by soil and returned to atmosphere through crops and trees, or stored in deep groundwater.

LANDWISE aims to look at the wider landscape and investigate ways to reduce the volume of water entering river channels in the first place

Dr Joanna Clark, Associate Professor of Environmental Science at the University of Reading, and project lead, said, “If you think about the land surface as a bucket, then these different land use and management methods can help us to increase the size of that bucket and help to empty it so that it can hold more water when it rains again. This is about making small changes over the large catchment area as a whole, rather than large changes in small areas where flooding occurs.”

These more natural methods, including crop choice, land preparation, building soil organic matter and tree-planting, can reduce the amount of water that runs off the land surface. They improve soil structure to allow more rainwater to infiltrate below ground.

CEH’s role in LANDWISE will be to collect key field evidence into the effectiveness of lowland land-based natural flood management measures, through wide-scale survey of soil hydrological and physical properties throughout the West Thames catchment.

Co-investigator Dr James Blake of the Centre for Ecology & Hydrology said, “In particular we are interested in the potential for NFM measures to increase soil permeability and soil water storage capacity, and therefore reduce rapid overland flows to rivers and hence reduce flood risk.”

Land-based NFM measures to be included in the surveys include land use changes such as woodland planting, arable land-use practices, for example, cover crops, livestock practices, alternative tillage practices, the use of buffer strips/zones and farm machinery management.

“In particular we are interested in the potential for NFM measures to increase soil permeability and soil water storage capacity, and therefore reduce rapid overland flows to rivers and hence reduce flood risk.” James Blake, Centre for Ecology & Hydrology

CEH co-investigator Dr Gareth Old said, “There are key knowledge gaps around the effectiveness of land-based natural flood management measures to reduce flood risk in lowland catchments. This innovative collaborative project will go some way to addressing those gaps with evidence-based science that will inform future approaches to minimising flood risk”.

The LANDWISE research focuses on the West Thames River Basin area, where around 112,000 properties are at risk of flooding if rivers burst their banks, almost 10,000 are at risk of groundwater flooding, and many more are in danger of surface water flooding. Work will initially focus on the Loddon, Pang and Upper Thames catchments, before being scaled up to the Thames river basin upstream from Oxford and Maidenhead. The project will explore whether broad scale changes in land use and management could have helped to reduce the severity of flooding events of July 2007 and winter 2013/14.

The project is one of three to be backed with funding from NERC’s £4.1m Understanding the Effectiveness of Natural Flood Management (NFM) programme, and will receive £1.25m.

Additional information

The University of Reading issued a press release for this story

Staff page of James Blake, Centre for Ecology & Hydrology

Staff page of Gareth Old, Centre for Ecology & Hydrology

Understanding the Effectiveness of Natural Flood Management (NFM) programme

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