The construction of water dams fundamentally changes nature and landscape not only in the flooded areas but also out of them, including all structures and links and leading to habitat loss. Three characteristically different South Moravian water reservoirs – the Vranov Dam, the Brno Dam and system of water reservoirs of Nové Mlýny have been studied in the project “Submerged cultural and natural heritage of South Moravia” (DF13P01OVV012) supported by the Ministry of Culture of the Czech Republic.
Within the framework of the sub-task “Evaluation of the impacts of drought on aquatic and water-bound organisms in surface water bodies“ a project involving activities to support the state administration in the drought issue in 2016 was prepared mainly a review of the potential impacts of drought on individual elements and indicators of water status assessment.
A categorization of the Czech Republic territory in terms of the risk of drying up of small streams (1st to 4th order by Strahler) was proposed. Three levels of risk (low, medium and high) for basic hydrological units (catchment) were set. The risk levels were defined using selected abiotic characteristics of the hydrological units and their combinations.