Hydromorphological index for rivers as an indicator of land use impact on watercourses in southern Poland

Study region: Southern PolandStudy focus: Land use has a significant impact on hydrological and morphological processes in river basins. Hydromorphology, combining these processes, plays a key role in the proper func-tioning of aquatic ecosystems. This paper presents the results of an analysis of hydro-morphological conditions for 77 sections designated on 39 watercourses related to semi-natural, agricultural, and urbanised land use. The study was carried out using the Hydromorphological Index for Rivers (HIR) method. Two components of the HIR were analysed: the Hydro-morphological Diversity Score (HDS) and the Hydromorphological Modification Score (HMS). New hydrological insights for the region: As studies show, the HIR Index can be successfully used as an indicator of the impact of land use on watercourses. There are significant differences in HIR between land use groups. The highest HIR values were recorded in semi-natural sections, while the lowest values were recorded in urbanised sections. In the studied region relatively high hydromorphological diversity was observed. It is also noticeable that the physical attributes of the channel correlate most frequently with the research sections in agricultural area. It has also been shown that hydromorphological diversity, apart from land use, is influenced by altitude, catchment size and geological type. This is an indication for decision-makers in the field of water policy that the proper land use plan in the catchment should be approached comprehensively.