Geomorphology within the interdisciplinary science of environmental flows

The field tradition in geomorphology informs beyond studying landforms by also providing a stage for understanding how geomorphic elements influence the ecology of biota. The intersection between fluvial geomorphology and riverine ecology represents an ideal confluence to examine the contribution of the geomorphic field tradition to environmental flows, and show this area of riverine management as a research frontier for applied geomorphology. Environmental flows have consisted of a set of ecological-based stream flow guidelines designed to inform sustainable water resource management that supports healthy riverine habitats and provides sufficient water supply for society. Geomorphological understanding is central to environmental flows because it is the interaction between flow, form, and substrate that influences habitat type, condition, availability and biotic use across space and time. This relationship varies longitudinally, laterally, vertically, overtime, and across macro- to mesoscale morphologies within the riverine environment. The geomorphic template is, therefore, as integral as the flow. We reviewed studies where field evidence indicated that geomorphology impacts the effectiveness of environmental flow strategies and we make the case for the need to increase geomorphic considerations in environmental flows. Although flow is commonly referred to as the master variable in environmental flows, geomorphology mediates the effects of flow regime on ecological processes. Concepts and applications from this perspective on the role of geomorphology in riverine ecosystem research will inform the practice, policy, and implementation of environmental flows.