The Hydrology of Alaskan Wetlands, U.S.A.: A Review

Abstract

Alaska's wetland resources are vast and the literature dealing directly with any given aspect of Alaskan wetland hydrology is sparse. This review focuses on hydrological function and pays particular attention to (1) hydrologic inputs to and outputs from wetlands, and (2) the influence of wetlands on peak flow regulation. The influence of several characteristic high-latitude phenomena (permafrost, glaciers, and seasonal stream icings) on the overall water balance and the volume, areal distribution, rate, and timing of water release are discussed. We find that (1) measured annual precipitation exceeds calculated annual evapotranspiration in most areas of the state, creating conditions suitable for the development of ombrotrophic wetlands; (2) during snowmelt, which is the principal event in the annual hydrologic cycle in most areas of the state, wetland soils typically have high ice contents, and thus probably do not contribute significantly to either flood storage or groundwater recharge, and (3) the existence of permafrost is critical to the existence and functioning of much of the areal extent of wetlands in the state. The implications of the state of our current understanding of Alaskan wetland hydrology for wetlands management are discussed.