The overall good status objective represents surface water conditions that are appropriate for all types of water uses and functions, besides healthy aquatic ecosystems. As with the TMDL in the United States, the WFD implementation requirements mean that modelling is increasingly being used by member states to characterise current environmental conditions and to predict for policy makers the potential impact of different abatement strategies (Collins and Anthony, 2008). However, monitoring of agricultural pollution of water bodies is more limited with just over a third of OECD member countries monitoring nutrient pollution and even fewer countries tracking pesticide pollution.