Principles of snow hydrology

Snow hydrology is a specialized field of hydrology that is of particular importance for high latitudes and mountainous terrain. In many parts of the world, river and groundwater supplies for domestic, irrigation, industrial, and ecosystem needs are generated from snowmelt, and an in-depth understanding of snow hydrology is of clear importance. Study of the impacts of global warming has also stimulated interest in snow hydrology because increased air temperatures are projected to have major impacts on the snow hydrology of cold regions.

Snow Hydrology describes the factors that control the accumulation, melting, and runoff of water from seasonal snowpacks over the surface of the earth. This research field addresses not only the basic principles governing snow in the hydrologic cycle, but also the latest applications of remote sensing, and principles applicable to modeling streamflow from snowmelt across large, mixed land use river basins.

Figure: Estero Monos de Agua Basin. Central Andes, Chile

Although history suggests that technical understanding of snow hydrology was a relatively recent phenomenon, some evidence exists that the role of snow was understood by some very early in our study of the physical world. References to the philosophy of the ancient Greek, Anaxagoras (500–428 BCE), indicate a rather surprising early understanding of the relationships between river flows and freezing and thawing of water, for example (Franks 1898): “The Nile comes from the snow in Ethiopia which melts in summer and freezes in winter” (Aet. Plac. iv 1;385); “And the Nile increases in summer because waters flow down into it from snows at the north” (Hipp. Phil. 8; Dox. 561).

Much later, literature from the writings of naturalist/geologist AntonioVallisnieri (1661–1730) in Italy showed specific recognition of the role of snow in hydrology. He correctly theorized that rivers arising from springs in the Italian Alps came from rain and snowmelt seeping into underground channels.

In the United States during World War II, the US Army Corps of Engineers and the USWeather Bureau initiated the Cooperative Snow Investigations in 1944 (US ArmyCorps of Engineers, 1956). The snow investigations were organized to address specific snow hydrology problems that were being encountered by both agencies. In order to meet snow hydrology objectives of both agencies, it was deemed necessary to establish fundamental research in the physics of snow. An extensive laboratory program across the western United States was established and observations were gathered starting in 1945. Analysis of these data formed the basis for developing the basic relationships and methods of application derived to develop solutions to the key snow hydrology problems (US Army Corps of Engineers, 1956).