Tundra Rehabilitation In Alaska's Arctic.

In the oil fields of Alaska’s Arctic, commonly referred to as the North Slope, site rehabilitation is required when new utilities are installed, old facilities are removed, or a spill occurs. Nearly the entire region is considered jurisdictional wetlands. Site remediation and preparation is completed in the winter when the ground is frozen and ice roads can be built to support heavy equipment, if needed. Most sites are excavated to an elevation equal to tundra grade. If gravel is removed from a site, the surface soil and remaining gravel is mixed to provide a good seed bed for summer treatment. Where thick gravel will remain in place, overburden (organic surface soil) is sometimes spread to provide a fertile seed bed. The sites are revisited in the summer and fertilized, seeded, or planted with tundra “plugs” with the goal to reach 10 percent cover with vascular plants (not including seeded grasses) in 10 years.

Because of the cold, wet conditions, short growing season, and the cutting-edge nature of this work, there are many challenges to successful site rehabilitation. It was originally thought that settlement due to ground ice thaw would be the greatest obstacle to overcome, but large-scale thermokarst has not proven to be a problem. Instead, soil moisture and soil nutrients appear to be the limiting factors. Where utility trenches are dug, subsidence is a problem, capturing and channeling surface waters causing the trench to expand laterally.