Progress in permafrost hydrology in the new millennium

Increased attention directed at the permafrost region has been prompted by resource development and climate change. This review surveys advances in permafrost hydrology since 2000. Data shortage and data quality remain serious concerns. Yet, there has been much progress in understanding fundamental hydrologic processes operating in a wide range of environments, from steep mountainous catchments, to the Precambrian Shield with moderate relief, to the low‐gradient terrain of plains, plateaus and wetlands. Much of the recent research has focused on surface water, although springs and groundwater contribution to streamflow have also been studied. A compendium of water‐balance research from 39 high‐latitude catchments reveals the strengths and limitations of the available results, most of which are restricted to only a few years of study at the small watershed scale. The response of streamflow to climate receives continued if not increasing attention, from the occurrence of extreme hydrologic events to the changing regimes of river flow at a regional scale. The effect of climate change and the role of permafrost on the changing discharge of large boreal rivers are major topics for further investigation. Extended field and modelling research on physical processes will improve knowledge of permafrost hydrology and enhance its relevance to societal needs. Copyright © 2008 John Wiley & Sons, Ltd.