© 2020 Elsevier LtdSmall Hydropower (SHP) plants interrupt river continuity, fish migration, and change downstream flow regime during operation. This study quantifies the ecological impacts of Small Hydropower (SHP) plants by using environmental monitoring data, site surveys and documented evidence based on an integrated approach. The ecological criteria are taken from the internationally recognized Swiss Water Protection Act and EU Water Framework Directive as follows: (i) environmental flow, (ii) hydropeaking, (iii) fish protection and fish passage, and (iv) sediment management. For a case study, Çataloluk SHP plant's, which has been in operation in the Ceyhan River Basin in Turkey, ecological impact has been assessed. The ecological impact scorecard of the facility reveals that there are significant gaps relative to basic good practice for hydropeaking, downstream fish passage, and sediment management. The following mitigation measures are proposed: enhancement of the environmental flow, construction of a retention basin for hydropeaking, installation of fish-friendly fine screens at the water intake, installation of brush blocks and substrate in the pools of vertical slot fish pass, and the usage of hydro-suction technology for sustainable sediment management.