Native grasses help USACE restore former defense site
August 15, 2011
- Vegetation is being used to protect a soil cover at the former Kentucky Ordnance Works, McCracken County, Ky.
- Vegetative cover also provides a habitat for birds and small animals that call the grassland community home.
LOUISVILLE, Ky. -- Green plants have many purposes in the environment, they serve as a habitat for small animals, provide food for others and for the U.S Army Corps of Engineers (USACE), they serve as a mechanism to protect remediated sites. At the former Kentucky Ordnance Works (KOW) in McCracken County, Ky., vegetation is being used to protect a soil cover, while also providing a habitat for birds and small animals that call the grassland community home.
The former Kentucky Ordnance Works served as an explosives manufacturing facility during World War II, producing approximately 196,490 tons of TNT. The site was decommissioned soon after the end of the war and the buildings were removed. During the operations and demolition of the site, waste material, including coal ash and construction debris, was disposed of in a 2.5-acre area known as the West Gravel Pits.
During the USACE Louisville District’s environmental investigation of KOW, it was determined that most of the waste material in the West Gravel Pits had been covered with native saoils, but some of the material was open to the environment.
“Sampling of the West Gravel Pits showed concentrations of metals in the surface soils that represented a threat to wildlife,” said Louisville District technical manager Doug Meadors.
The selected remedial action was to construct a soil cover over the area and re-route surface drainage. Site work was performed in 2009. A soil cover acts as a barrier between the buried waste and the surface, preventing the public and environment from being exposed to the waste.
“Key to maintaining the soil cover is having plants living on the cover material,” said Meadors. “If the soil cover was not covered in vegetation, water from storms could erode the cover away over time.”
The vegetative cover was established by seeding the area with native warm season grasses, including Indian Grass, Big Bluestem, Little Bluestem and Praire Switchgrass. Native warm season grasses are tolerant of dry weather and other environmental challenges. Erosion-resistant mats were also placed on various slopes of the site to provide a stable base for the grasses to take root. Vehicle traffic is prohibited from the site to prevent erosion of the installed cover.
The grasses continue to flourish on the West Gravel Pits, and plant growth will eventually contribute to the creation of soil structure and wildlife habitat.
“Kentucky was once covered by about 3 million acres of grasslands and much of the Kentucky grasslands were populated with bison,” said Meadors. “This planting harkens back to how Kentucky looked in those pre-settlement days.”