Snow hydrology in watershed analysis

Watershed analysis refers to evolving systems of procedures for characterizing hydrologic and ecosystem processes within catchments as input to land management plans and practices. The most formalized approaches to watershed analysis were developed by the Washington Forest Practices Board and the Forest Ecosystem Management Assessment team and its successors. Watershed analysis seeks to determine critical processes and their extent, condition of the landscape and channel, impacts of past practices, location of sensitive areas, existing problems of water regime and quality, influences on aquatic habitat, and other information about watersheds relevant to resource planning and management activities. In higher-elevation basins, information about snow cover and snowmelt processes is necessary for a thorough watershed analysis. Characterization of a basin’s snow hydrology provides fundamental knowledge for understanding temporal and spatial patterns of water availability for runoff. The typical distribution of snow and related synchronization of tributary flows, alterations in snow cover from past harvesting, and potential for rain-on-snow peak flows can influence land management options.