Building good fences could make our water cleaner, and help us to meet European standards, according to researchers working on the UK research councils' Rural Economy and Land Use Programme (Relu).
Relu scientists have created a computer model to investigate the problem of fecal pollution in UK rivers. The organisms come mainly from farm animals' feces and untreated human sewage.
As sewage treatment has improved over recent years, human sewage is less problematic, except in times of heavy rainfall, when less efficient treatment works pose a threat. But livestock, and dairy cattle in particular, continue to be a major contributor of harmful organisms. The research shows that there is a high risk of fecal pollution entering watercourses within areas with high densities of dairy cattle.
The UK has to tackle this problem, not only because of the health risks for those such as canoeists and paddlers, especially children, who are directly exposed to pollution in rivers, but also because of European legislation. At the moment, many of our watercourses do not meet the requirements of the European Water Framework Directive.
One way of reducing the numbers of fecal organisms would be to have fewer farm animals grazing in vulnerable areas near rivers. But, for some dairy farmers, a reduction in stocking densities could have serious implications for their livelihoods and there could be economic consequences for wider rural communities.
So, drawing on work from several projects across the Relu research program, the team created a computer model to investigate different approaches to tackling the problem. These included government interventions that would directly restrict stocking levels and simpler, everyday solutions, such as erecting fences to prevent livestock depositing feces directly into watercourses.
They found that simple farm-scale solutions are likely to be most effective at reducing the numbers of potentially dangerous organisms entering watercourses -- and could work out cheaper both for farmers and consumers.
Danyel Hampson, from the University of East Anglia, who worked on the computer model, said: "We looked at several policy options available to Defra, such as designating at-risk areas as environmentally sensitive areas, direct restraints on production such as reducing the number of cattle, and taxing nitrogen fertilizers to curb their use, thereby lowering the nutritional quality of the grass, so that the land would feed fewer animals and be grazed less intensively.
"But animals having direct access to the water seems to be one of the major risks. The simple solution of fencing off cattle from rivers is probably one of the most effective ways farmers have of reducing fecal material contaminating watercourses. From the farmer's point of view, it is a solution that they can get on and do. What is more, funding for fencing is available to farmers from the Defra Catchment Sensitive Farming Capital Grant Scheme."
Professor Philip Lowe, Director of the Relu program added: "The installation and maintenance of streamside fencing is already supported to a limited extent under some agri-environment schemes, but these findings suggest that it would be beneficial to water quality if these options could be significantly extended and actively promoted to livestock farmers."
- Danyel Hampson, John Crowther, Ian Bateman, David Kay, Paulette Posen, Carl Stapleton, Mark Wyer, Carlo Fezzi, Philip Jones, Joseph Tzanopoulos. Predicting microbial pollution concentrations in UK rivers in response to land use change. Water Research, 2010; DOI: 10.1016/j.watres.2010.07.062
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