Assessment of the River Habitat Quality Using Bioindication in the Piedmont Stream Handlovka in Slovakia

The paper focuses on an assessment of a river habitat quality in piedmont streams using a bioindication by the brown trout. The study was performed at four sites, piedmont streams in Slovakia, but modelling procedure herein is particularly described only for the Handlovka River, in the Nitra basin. For the field and modelling work, a natural reference reach and a regulated reach have been chosen within each stream. Hydrometric, geodetic and morphological measurements were conducted. The paper focuses on modelling in the Hydrocheck software and Computer Software System for Environmental Flow Analysis (SEFA) based on the Instream Flow Incremental Methodology (IFIM) and result output is the Area Weighted Suitability (AWS). The abiotic parameters for modelling were chosen as depth and velocity rates. The biotic parameter was chosen as an ichthyologic abundance of the brown trout. The results show significant difference between natural and modified channel, presenting natural reach as more suitable for fish abundance with higher AWS score. The regulated reaches are significantly affected by the river regulation, construction of concrete panels and sever contamination from anthropogenic runoff. On the contrary, the natural channels offer enough morphological structure and various shelter possibilities for enhancement of fish population.