8. Overview of Environmental Flows in Permafrost Regions

River ecosystems have adapted to a natural range of variability in magnitude, timing, duration, and predictability of key hydrograph components, such as high- and low-flow periods. However, the timing, magnitude, and variability of cold region flow regimes are changing in response to a warming climate, water abstraction, and building of impoundments. Changes in water quantity flowing down a river at a given time have the potential to adversely and/or positively affect habitat conditions and sustainability of ecological diversity within both the river and associated riparian and floodplain zones. There is a growing need to incorporate environmental flow assessments in the management of permafrost regions in response to changing flow regimes in order to preserve these diverse ecosystems. Environmental flows are defined as the quantity, timing, and quality of freshwater flows and levels necessary to sustain aquatic ecosystems. The goal of this Chapter is to present an overview of environmental flows for permafrost regions, with a focus on North America where information is most readily available. This goal is achieved via a review of (i) cold regions hydro-ecology, (ii) history and application of environmental flows internationally, (iii) environmental flow guidelines and policy in Arctic states, and (iv) riverine monitoring in northern regimes to support environmental flow frameworks. Several key recommendations to address knowledge and data gaps to better manage natural resources are provided.