Abstract
Sustainable development supports watershed processes and functions. To aid the sustainable development of the western Balkans' transboundary river and lake basins, the Regional Environmental Center for Central and Eastern Europe and the US Environmental Protection Agency (EPA) adapted the EPA's Index of Watershed Integrity (IWI) following the devasting 2014 floods in Albania, Bosnia and Herzegovina, Kosovo, North Macedonia, Montenegro, and Serbia. The IWI evaluates six watershed functions based on a suite of anthropogenic stressors (e.g., impervious surfaces, reservoirs). A key feature of the IWI is its ability to accumulate the impact of upstream activities of any specific location in a river network. A novel feature of the IWI, compared with other watershed assessment tools, is its capacity to provide actionable information at the local scale. IWI scores-ranging from 0 (low integrity) to 1 (high integrity)-calculated for the 1084 catchments of the study area indicated highest integrity in the Alpine geographic region (mean = 0.55, standard deviation (SD) = 0.11) and intermediate to lowest integrity within the Mediterranean (mean = 0.49, SD = 0.12) and Continental (mean = 0.40, SD = 0.10) geographic regions. The IWI results are presented hierarchically for data analysts (stressor, functional component, Index of Catchment Integrity and IWI), ecologists (stream/catchment, watershed, basin), and managers (local, national, international). We provide real-world examples for managers, and suggestions for improving the assessment.