Farming pollution study offers unexpected clue to flooding

Story supplied by LU Press Office

With communities still enduring the devastating effects of severe flooding across the UK, environmental scientists and statisticians at Lancaster University have published new research which suggests changes in agricultural land use management have the potential to reduce water run-off from fields.

Within Europe, the number of people affected by river flooding has been projected to increase from 150,000 to 400,000 by 2100, during which time expected annual damages from flooding are expected to increase from 6.4 billion euros to at least 14 billion euros. Much attention has been paid to the effects of urbanisation on flooding but there are now concerns that the effects of agricultural intensification and land use practices may also have had an impact.

Scientists studying the effects of different agricultural farming techniques on pollution made an interesting discovery when they analysed the run-off water from a field sites in Leicestershire. They found that by cultivating the soil in different ways the amount of rainwater flooding off the field could be reduced.

Between 2007 and 2008 surface rainwater was collected from 17 strips of fields on hillsides using several different farming methods including: traditional ploughing, minimally tilled fields, fields which were ploughed and planted across the hillside and those which were cultivated up and down the slope. They also compared fields with tramlines - unvegetated, compacted tracks for machinery to use - compared to those with no tramlines.

The results, published in the Journal of Environmental Management, suggest some surprising trends and possible effects of the different methods and highlighted difficulties of collecting sufficient data to obtain statistical significant estimates. Minimal tilling produced more rainwater runoff than traditional ploughing methods, while fields cultivated across the slope, rather than up and down, surprisingly also produced more run-off. Tramlines also reduced the land's ability to hold on to rainwater.

The researchers are now calling for further work in this area to provide more robust results.

Lancaster University's Professor John Quinton, who wrote the study along with Dr Clare Deasy and Dr Andrew Titman, said: "This is a much under-researched area of flood prevention. These results suggest that the way in which the field was ploughed and cultivated had an impact on how much water ran off the field and how quickly it happened. As this could have an impact on downstream flood responses, changes in in-field management could potentially be used to reduce risk of flooding downstream."

Fri 17 January 2014