Water Cycle Dynamics in the Snake River Basin, Alaska

Alaska’s Seward Peninsula is underlain in the south by areas of near-freezing, continuous and discontinuous permafrost. These conditions make it susceptible to changing climatic conditions such as acceleration of the hydrologic cycle or general atmospheric warming. This study looks at the hydrologic record of the Snake River over the mid-twentieth century through present. The Snake River basin drains an area of about 22 square kilometers into Norton Sound near the Bering Strait, off the western coast of Alaska. Climate for this area is maritime in summer and somewhat continental in winter once the sea ice forms. Hydrometeorological parameters have been measured locally for more than fifty years with temperature being measured regularly over the last 100 years. Discharge has been measured in the Snake River intermittently over that time period as well. This study looks closely at drivers of inter-annual variations in soil moisture in the basin over the observational record using a physically based numerical hydrological model. Unlike many areas of Alaska, the meteorological record at Nome, located at the mouth of the watershed, shows no statistically significant increase in precipitation over either the last 30 years or the last 100 years. However, there has been a small increase in temperature over the 100 year time period.