State of the art, shortcomings and future challenges for a sustainable sediment management in hydropower: A review

It is predicted that 60% of all new energy investments over the next 20 years will be in renewables. The estimation for new hydropower production is 25% of all new renewables primarily due to potential in China, Africa, Latin America and South-East Asia. Also in Europe a growth of hydropower production is aimed to achieve emission targets within the European Union by 2050. However, one of the main economic, technical and ecological challenges in future are the deposition, the treatment, and the disturbed dynamics of sediments in river catchments, which reduce the future market potential of hydropower substantially. Due to a lack in awareness of those sedimentological challenges (e.g. lack of process understanding), various huge economical, technical and ecological problems emerge with an increasing relevance for hydropower industry, water management authorities and the society in future. Based on a substantial literature review, (i) legal frameworks and (ii) reservoir management techniques including (iii) process understanding and numerical modelling are addressed in this article. Moreover, the relevant cost-effective aspects of abrasion are worked out for (iv) turbine runners and (v) sediment bypass systems as well as the (vi) the ecological relevance of sediments and possible disturbances are described in this manuscript to open a future discussion on technical opportunities. It was concluded, that all these issues should be addressed within the framework of the overall aim to minimize the costs under consideration of ecological requirements and standards by an improved sediment management in terms of hydropower use. Moreover, it was stated that trans- and interdisciplinary research is required, to achieve those aims in future.