Assessment of river quality within the context of the EU's water framework directive (2000/60/EC): the RiverNet Experiences


The purpose of the EU's Water Framework Directive (WFD)is the achievement of ecological good status for all its superficial water bodies and courses.However,the most controversial and difficult aspect is the choice of an appropriate method to define a “reference condition ”,the expected value upon which comparisons are to be made and quantitatively expressed as EQR metric (ecological quality ratio).A major burden is the adjustment of national standards to assess the quality of aquatic habitats according to the technical specifications explicitly stated in the WFD.This aspect is also one of the major objectives within the RiverNet project.We compared standard methods used in Italy (not compliant with WFD requirements)with those currently under study by the pan-European intercalibration panel.Data spanning one year (2002)from the Abruzzo monitoring programwere used.Data from 229 samples (78 sites and 38 water courses)were reanalyzed using both Italian (LIM,IBE,SECA)and other metrics (family richness,BMWP,ASPT,EPT,EPT%).Resulting ecological status assessments were compared quantitatively and expressed as EQR.Indices based on benthic invertebrates were closely interrelated ($R2==0.71 –0.88 for pairwise correlations),and performed better than the abiotic LIM index.The BMWP index seems better suited than the non-WFD-compliant IBE index to describe ecological status.Though the dataset was relatively limited,we were able to identify 13 class-1 (least impacted)sites that can be used as reference sites for Abruzzo.Additionally,EQR-based range and threshold values for each tested metric were quantified for the high, good and moderate quality lasses.Utilization of historical data may be a cost-and time-effective approach potentially leading to a regional and nationwide establishment of reference conditions and range quality-class values for riverine systems.

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