The Institution of Agricultural Engineers (IAgrE) calls for renewed focus into soil and water drainage.
Commenting on the recent appalling weather and devastation to farmlands Alastair Taylor IAgrE CEO said: “The current extreme weather is definitely bringing into emphasis how the nation has neglected land drainage and flood mitigation work. This brings into focus the role of agricultural engineers, specialising in soil and water engineering, in preventing, or at least minimising the impact of any future weather event.”
The country’s inability to cope could be demonstrated by the fact that a number of land drainage systems, mostly installed in the 60s and 70s, are ill equipped to deal with the heavy rainfall, with silting and damaged existing pipe work being common problems. Mike Hann, drainage consultant, Chartered Engineer and IAgrE Fellow comments that mole drainage, very commonly practised in heavy soil regions, often has a life-span of less than 30 – 40 years rendering the soils liable to much greater levels of run-off contributing to flooding.
Farmers are discovering first hand why they need to invest in improvements to their land drainage and many are beginning to factor drainage operations into their annual timetable.
IAgrE Fellow and Chartered Environmentalist Jane Rickson who is a soil science specialist added: “Flooding not only occurs when water tables are high; a lot of the flooding is due to soil condition (and not just saturated soil profiles). Infiltration of rainwater into the soil is severely limited by loss of soil structure due to compaction. The use of increasingly larger and heavier machinery causing soil surface smearing, especially on wet soils. High animal stock densities, over working the soil, losses of organic matter, soil biology and so on all add to the problem.
You often find the soil is relatively dry over a spade-depth down because water cannot infiltrate – it was certainly the case during the floods around Tewkesbury a few years ago. Without soil and water storage, flooding risk is increased.”
Many drainage schemes are poorly maintained (sometimes deliberately so for ecological restoration, other times due to lack of investment/financial support). The concern is that draining land or dredging of channels will simply send the flood water somewhere else, possibly at a faster rate, so peak floods might be even higher in downstream areas … possibly urban areas with higher population densities.
Summing up Alastair Taylor said: “It is important that lessons are learnt from this current crisis. We need more agricultural engineers with an understanding of soil and water engineering. Environmental courses and training programmes need to include more focus on this vital subject. We need environmentalist to have a better understanding of the agricultural engineering solutions to this significant challenge.”
Mike Hann adds, “Improved soil management results in improved soil/water storage which will lower the risk of flash-floods, especially downstream.”