At the heart of the interdisciplinary science of Ecohydraulics is the study trilogy of river restoration (including dam removal and wetland rehabilitation), e-flows (ecological, environmental or instream flow regimes), and passage systems for migrations of fish and other aquatic organisms.  These ecohydraulic science themes have been developed to a large degree independently, yet they form a holistic trilogy compatible with ecological engineering principles aiming to realize and maintain healthy and sustainable aquatic ecosystems.  These three study areas rely on classical aspects of ecology, biology, habitat quality, population dynamics, hydrology, water quality, hydrodynamics, ice dynamics and morphodynamics, but synthesize such aspects in new ways.  Ecohydraulics is considered the culmination of all these study areas into a coherent science, which includes ecohydrology, ecomorphology and other eco-physical syntheses.  Ecohydraulics has enabled, and continues to promote, interdisciplinary advances as the best way to develop ecologically compatible solutions.  Such advances have reached a level where integration of the ecohydraulic trinity science themes may enable efficiencies, synergies and more sound ecologically-based designs.  For example, river flows to attract and pass fish and other aquatic organisms, e-flows, as well as flows to ensure restoration measures are effective, assess parallel ecohydraulic characteristics and serve congruent purposes.  A more integrated study of fish attraction (5-10% of river flows), e-flows (80-95% exceedance flows), and flows near bankfull discharge, which are key to river restoration and habitat modifications, may benefit both ecological and project needs.  Integrating all three maximizes synergistic opportunities for more holistic, effective and balanced projects and mitigation measures.