Forecasting the effects of EU policy measures on the nitrate pollution of groundwater and surface waters

We used the interdisciplinary model network REGFLUD to predict the actual mean nitrate concentration in percolation water at the scale of the Weser river basin (Germany) using an area differentiated (100 m × 100 m) approach.REGFLUD combines the agro-economic model RAUMIS for estimating nitrogen surpluses and the hydrological models GROWA/DENUZ for assessing the nitrate leaching from the soil.For areas showing predicted nitrate concentrations in percolation water above the European Union (EU) groundwater quality standard of 50 mg NO 3 -N/L,effective agri-environmental reduction measures need to be derived and implemented to improve groundwater and surface water quality by 2015.The effects of already implemented agricultural policy are quantified by a baseline scenario projecting the N-surpluses from agricultural sector to 2015.The REGFLUD model is used to estimate the effects of this scenario concerning groundwater and surface water pollution by nitrate.From the results of the model analysis the needs for additional measures can be derived in terms of required additional N-surplus reduction and in terms of regional prioritization of measures.Research work will therefore directly support the implementation of the Water Framework Directive of the European Union in the Weser basin.     

Forecasting the e ects of EU policy measures on the nitrate pollution of groundwater and surface waters

We used the interdisciplinary model network REGFLUD to predict the actual mean nitrate concentration in percolation water at the scale of the Weser river basin (Germany) using an area di erentiated (100 m 100 m) approach. REGFLUD combines the agro-economic model RAUMIS for estimating nitrogen surpluses and the hydrological models GROWA/DENUZ for assessing the nitrate leaching from the soil. For areas showing predicted nitrate concentrations in percolation water above the European Union (EU) groundwater quality standard of 50 mg NO3-N/L, e ective agri-environmental reduction measures need to be derived and implemented to improve groundwater and surface water quality by 2015. The e ects of already implemented agricultural policy are quantified by a baseline scenario projecting the N-surpluses from agricultural sector to 2015. The REGFLUD model is used to estimate the e ects of this scenario concerning groundwater and surface water pollution by nitrate. From the results of the model analysis the needs for additional measures can be derived in terms of required additional N-surplus reduction and in terms of regional prioritization of measures. Research work will therefore directly support the implementation of the Water Framework Directive of the European Union in the Weser basin.     

Application of a linear regression model to assess the influence of urbanised areas and grazing pastures on the microbiological quality of rural streams

Faecal coliform (FC) bacteria were used as a proxy of faecal indicator organisms (FIOs) to assess the microbiological pollution risk for eight mesoscale catchments with increasing lowland influence across north-east Scotland. This study sought to assess the impact of urban areas on microbial contaminant fluxes. Fluxes were lowest in upland catchments where populations are relatively low. By contrast, lowland catchments with larger settlements and a greater number of grazing populations have more elevated FC concentrations throughout the year. Peak FC counts occurred during the summer months (April–September) when biological activity is at its highest. Lowland catchments experience high FC concentrations throughout the year whereas upland catchments exhibit more seasonal variations with elevated summer conditions and reduced winter concentrations. A simple linear regression model based on catchment characteristics provided scope to predict FC fluxes. Percentage of improved grazing pasture and human population explained 90 and 62 % of the variation in mean annual FC concentrations. This approach provides scope for an initial screening tool to predict the impact of urban space and agricultural practice on FC concentrations at the catchment scale and can aid in pragmatic planning and water quality improvement decisions. However, greater understanding of the short-term dynamics is still required which would benefit from higher resolution sampling than the approach undertaken here.