A short-cut methodology for the spatial assessment of the biochemical river quality

Abstract

Abstract The deterioration of superficial water quality is a relevant issue as regards water management. Today, most European rivers do not achieve qualitative standards defined by Directive 2000/60/EC (Water Framework Directive, WFD), while health status of many surface water bodies is still unknown. Within this context, we propose a new methodology to perform a semi-quantitative analysis of the pressure-state of a river starting from easily accessible data regarding the anthropic activities, thus attempting to overcome the endemic scarcity of monitoring records. This study proposes a procedure to: (i) evaluate the relative impact of different human activities; (ii) identify allocation points of different pollutant sources along the river by implementing a raster-based approach and (iii) determine a spatial biochemical water quality index. The developed index expresses the overall biochemical state of surface water induced by pollutant sources that may impact simultaneously on a single river segment, including establishments under so-called Seveso Directive, activities subjected to the IPPC-IED discipline, wastewater treatment plants and contaminated sites. The methodology has been tested over three rivers differently exposed to industrial and anthropogenic pressures: Reno, Enza and Parma rivers (Northern Italy). The comparison with monitored data offered convincing results, proving the consistency of the proposed index in reproducing the spatial variability of the river water quality. Although additional investigations are necessary, the developed methodology can represent a valuable tool to support decision-making processes and predictive studies in areas with no, or poor, water quality monitoring data.