Oct. 20, 2010 – There are plenty of high-tech ideas to tackle pollution, but recent research suggests that some of the biggest gains in keeping our waterways clean could come from a more traditional technology – fences.
Simply fencing off streams and drainage ditches so farm animals can’t deposit manure in and around them could cut levels of faecal pollution dramatically, according to scientists. This would protect the health of people exposed to river water and help Britain comply with EU rules on water quality.
The researchers created a model of the various factors that lead to faecal pollution – and the harmful bacteria it contains – in rivers. They then used the model to work out how effective different methods aimed at cutting faecal pollution would be, using the Humber river basin as a case study.
Fencing off streams came out ahead by a big margin – the model suggests that by the time water flows out of a region of intensive dairy farming, its E. coli concentrations would be 58.59 per cent lower with fenced streams than without. As well as keeping animals away, the fences encourage the development of an overgrown riverbank zone which can help filter out faecal matter that’s washed off fields.
This is just one of several possible ways to address the problem. ‘But animals having direct access to the water seems to be one of the major risks,’ says Danyel Hampson, a PhD student at the University of East Anglia and lead author of the paper, published in Water Research. ‘The simple solution of fencing off cattle from rivers is probably one of the most effective ways farmers have of reducing faecal matter contaminating watercourses. From the farmer’s point of view, it is a solution that they can get on and do.’
Alternatives may be less effective, more expensive and more disruptive for farmers. For example, reducing the number of dairy cows in the area, the second-most-effective measure, would only lead to an 11.58 per cent reduction. The third-most-effective, cutting fertiliser use by 20 per cent to make grass less nutritious so that fewer cows can be kept on it, would cut bacterial rates by less than ten per cent. Both these measures would probably be much more painful for farmers.