Most commonly, hydropower operation focused on the economic and social benefits of the humankind, whereas neglecting the riverine ecosystem conservation. This conventional approach of operation led to the degradation of the riverine ecosystem. As research progressed, adoption of natural flow variability in the operation of reservoir gained momentum. Flow variability is a major driver of the healthy river ecosystem, whereby discharging a certain amount of water could potentially reduce the adverse effect of reservoirs and dams on the riverine ecosystem. On this preface, the study presented here constitutes a multi-objective optimisation model of cascade reservoirs to maximise the power generation while minimising the shortage of environmental flows considering five environmental management classes. This paper analyses the case studies for Liujiaping-Yumitan cascade reservoirs. The environmental flows regarding each environmental management classes were calculated using "Global Environmental Flow Calculator", the model was solved using an anon-dominated sorting genetic algorithm (NSGA-II). The NSGA-II helps to find Pareto optimal sets of solutions, NSGA-II, however, cannot be used solely for taking a comprehensive decision. Therefore, the Projection Pursuit Cluster (PPC) model has been used additionally for the optimal sequencing of the compromised optimal solutions. The maximum annual power production considering five environmental management classes were respectively: 1.121, 1.109, 1.103, 1.109, and 1.117 (x10(8) kWh) with environmental flows shortage of 2060.82, 616.497, 200.52, 28.88, and 0.004 (x10(4) m(3)) respectively. Findings resulted from this study, highlight the necessity for power production compromise for a better degree of environmental protection. In contrast, the environmental benefit is more important not only for the sustainable operation of the hydropower but also for fulfilling the universal needs of the riverine ecosystem. Therefore, the outcomes of this study can be a guideline for decision-makers to improve the comprehensive benefits of the Liujiaping-Yumitan cascade hydropower station along with the conservation of the environmental health of the river. (C) 2020 Elsevier Ltd. All rights reserved.