CHANGES in farming practices over the past 20 years may have contributed to
up to a fifth of the severe flooding seen across England and Wales over the past
fortnight.
“Farmers used to plough their fields and then leave them bare through the
winter, so water collected on the land, filling furrows and infiltrating into
the aquifers beneath,” says Geoff Mance, director of water management at
Britain’s Environment Agency. “Now they mostly plant winter cereals, sometimes
without ploughing at all.” Rainwater drains straight off the resulting smooth
surface. “We have a huge acceleration in the speed that rainwater flows into
rivers, causing big flood peaks after storms.”
Record rains were clearly the major problem last week. But studies on small
river catchments have shown a “15 to 20 per cent increase in peak river flows
from changing farming methods”, says Mance. The government should be diverting
money from building flood defences to reducing run-off, he adds.
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Soil scientists agree that more could be done on farms to prevent flooding.
Dick Thompson of Cranfield University’s Soil Survey and Land Research Centre
near Bedford says: “There is less organic matter in soils than there was 15
years ago. We know that causes a hard cap to form on soils, which prevents water
infiltrating into the soil.”
Mance also wants town planners to insist on permeable pavements that soak up
rainwater, more urban lakes and making developers reduce run-off from gardens,
driveways and car parks.