A tool for the selection and implementation of eco-remediation mitigation measures

Abstract

Erosion processes in the watershed and sediment transport cause hydro-morphological changes, eutrophication, and the loss of storage capacity in reservoirs. This study examines the tool for the optimal selection and implementation (TSI) of eco-remediation measures (ERM) in the river basin area to improve water quality and to reduce storage loss in the reservoir in question. The main purpose of this tool is to support decisions and measures taken to correct defined problems and to improve water quality and storage capacity in the watershed while minimising sediment transport. This tool enables the effective and necessary implementation of these measures to the most critical source areas (CSAs). In order to verify its operability, we selected the Ledava reservoir with a transboundary area of 105.25 km2 in NE Slovenia and SE Austria. With the use of the Soil and Water Assessment Tool (SWAT), critical source areas were determined and the effects of eight different scenarios on sediment yield and load transport were simulated. The results showed that CSAs occupy 12% of the watershed and that sediment inflow into the Ledavsko jezero reservoir could be reduced by up to 30%. After determining the CSAs and which measures would be most effective, the implementation plan could be defined. Within this framework, the TSI enabled the selection of effective measures and contributed to the long-term improvement of the ecological status of surface waters required by Water Framework Directive (2000/60/EC), improving the quality of water bodies of all types to safeguard water ecosystems from harmful consequences.