Extreme weather events such as prolonged droughts or flash floods are currently the most obvious signs of climate change. These disturbances are causing significant environmental stress to the wetland and aquatic communities. In the last century, the average temperature in the Carpathian Basin has increased by approximately 1°C. All of these alterations had a significant impact on the small streams, resulting in a typological shift in many of them: streams that had a permanent water supply became intermittent waters. In recent years, our research group has been studying the effects of stream drying on benthic algal assemblages in small watercourses in the Carpathian Basin. Here, we focus on the differences in diatom indices between (i) intermittent and permanent lowland streams and (ii) different phases of drying such as flowing, standing and dry phases