Effects of 45 Years of Heavy Road Traffic and Infrastructure on Permafrost and Tundra at Prudhoe Bay, Alaska

Abstract:

The upper permafrost of the Prudhoe Bay Oilfield, the largest oil field in both the United States and in North America, contains significant amounts of excess ground ice, mainly in ice wedges. An increase in infrastructure development and road traffic since the initial development of the Prudhoe Bay Oilfield in 1968 has resulted in extensive flooding, accumulation of road dust, and roadside snowbanks, all of which affect the vegetation and alter the thermal properties of the ground surface. As part of the NSF’s Arctic Science, Engineering, and Education for Sustainability (ArcSEES) project, we established four transects in 2014 and 2015 to document the effects of infrastructure and heavy road traffic on adjacent tundra. Two transects were established perpendicular to the Prudhoe Bay Spine Road north of Lake Colleen and two perpendicular to the Dalton Highway next to the Deadhorse airstrip. Prior to infrastructure development in 1949, rather homogeneous networks of low-centered polygons with less than 30 cm of trough-rim elevation contrast covered both locations. We present the detailed results of vegetation analysis, ice-core drilling, and extensive topographic surveys along the transects. A time series of aerial photographs from 1949 to 2014 (yearly since 1969) documents the changing landscapes in relationship to the record of air-temperature, active layer depths, and permafrost temperatures at Deadhorse. Flooding, road dust, and snow drifts have all contributed to creating warmer soil temperatures and deeper active layers near the road. These factors have all contributed in different ways to alteration of the plant canopy. The altered plant canopies in turn further altered the surface albedo and the ground temperatures. Historical photos indicate that between 1989 and 2012 a regional thawing of the ice-wedges occurred, increasing the extent of thermokarst. Our analysis demonstrates the cumulative effects of infrastructure-related and climate-related factors to these ice-rich permafrost landscapes.