The present study focused on benthic diatom and invertebrate communities from the Someșul Mic catchment area, between Someșul Rece and Apahida localities. Five sites were chosen, and they were sampled in spring, summer and autumn 2014. The area experienced major human impacts on aquatic communities, all caused by the existence of numerous urban and rural centers: discharges of waste waters into the natural streams, hydro-technical works for the production of energy or for water storage, hydropeaking, pollution coming from point or diffuse sources. The presence and the indicator value of the diatom species identified in the study area, together with the relative abundance of benthic invertebrate taxa were used to characterize the ecological status of the five sampling sites. Both diatoms and invertebrates showed the highest ecological status at the sampling site located on the Someșul Rece River, while the sampling sites located in or downstream Cluj-Napoca displayed the most impacted conditions. However, eutrophic conditions were characteristic to all sampling sites, showing affected biotic communities even in habitats with low human impacts
