New Protective Barrier Blankets Hanford Tank Farm

RICHLAND, Wash. – Workers have finished installing another surface barrier above a group of large underground waste storage tanks at the Hanford Site. The gravel and asphalt barriers help protect groundwater by diverting water from rain, snow, sleet, or hail to a lined basin.

“The water evaporates instead of permeating into the soil and driving existing contaminants closer to groundwater,” said Becky Blackwell, EM Office of River Protection (ORP) program manager for the barrier installation project. “The protective covers also reduce our costs for surveying and maintaining what was once a soil and gravel surface.”

In February, ORP contractor Washington River Protection Solutions (WRPS) awarded a subcontract to local firm Fowler General Construction to install three sections of high-density asphalt to form one large barrier over the 18 tanks that make up the TX Tank Farm.

Crews used about 4,000 tons of gravel and 6,000 tons of asphalt to construct the barrier that consists of a layer of gravel covered with four inches of compacted, high-density asphalt. Each 758,000-gallon tank in the TX Farm is 75 feet wide, and the barrier covers about 220,000 square feet — an area larger than four football fields.

In addition to protecting the groundwater beneath the tanks and reducing costs for surveying and maintaining the ground surface, the protective covers provide other benefits.

“The surface barriers also improve the stability of the tanks and the surrounding soil, and they provide a clean and stable platform for field crews while they work in the tank farm,” said Jim Geary, WRPS tank farm projects manager.

The surface barrier was constructed under an agreement between DOE, the Washington State Department of Ecology, and U.S. Environmental Protection Agency.