Subsurface hydrology in Arctic and Subarctic Regions

Groundwater and surface water combine to form a single water resource in Artic and Subarctic regions. Groundwater is a critical for providing water for streams, maintaining ecological systems, and as a water resource. Across Alaska, the Yukon, Northwest Territories, and Nunavut almost 50% of the population rely on groundwater for their drinking water supply, including more than 97% of Yukoners. There are many concerns about Northern groundwater vulnerability due to climate change as arctic warming is two to four times the global average rate, accompanied with increasing precipitation rates.

Detecting change in Arctic cryohydrogeologic systems is difficult due to a lack of groundwater observation data. We present results from government groundwater monitoring programs in Alaska and the Yukon, including initial results from the Yukon Observation Well Network (YOWN), a unique observatory for monitoring climate change impacts on northern groundwater. The YOWN was adapted from a small Yukon-wide observation program that started with one observation well at the outlet of the Wolf Creek Research Basin in 2001. The network is rapidly growing with now more than 75 wells between the latitudes of 60.04º and 67.57º, with continuous water level observations and periodic water quality measurements.

Observation well results show that groundwater levels follow seasonal and local climate trends, particularly for snow melt. Broadly, the wells show that groundwater recharge is dominated by snow melt, and most wells do not show a seasonal rise in water levels in the fall, as is seen at lower latitudes. The observations show that the snowpack from an antecedent winter is the primary control on a subsequent year’s groundwater levels. Many wells also show multi-year increases in both winter and summer water levels. This ‘groundwater staircase’ demonstrate that some cryohydrogeology systems are affected by multiyear climatic controls across the region. The results have important implications for managing water resource vulnerability and detecting climate change impacts on Northern groundwater systems.