New water-quality targets being established by the European Union could radically change the face of farming in Europe, forcing farmers to scale back or even abandon their practices in some traditionally agricultural areas. The Water Framework Directive will require all rivers, lakes, and canals to be restored to “good ecological quality” within 15 years — and the measure of “good” will be far stricter than current standards. Complying with the directive will require wide-ranging changes in land use, from substantial reductions in the number of sheep and cattle that can be kept to restrictions on the size and location of crop fields. Simon Harrison of Ireland’s University College, Cork, put it simply: “If you want to have nice rivers, there are going to be some changes in agricultural practices. This is a Europe-wide problem.” Maybe so, but it’s especially acute in Great Britain, where 95 percent of freshwater was polluted by farming sources in the 1990s.