Wood Hollow Training Area lies adjacent to the Utah Army National Guard's (UTARNG) Camp Williams. Used for artillery training since World War I, the site is now privately owned by the Staker-Parson Company for mining and quarry operations. Portions of Wood Hollow have been annexed by the city of Herriman, Utah, for future residential and commercial development.

Following a wildfire in the area nearly 10 years ago, UTARNG discovered artillery shells and other munitions and explosives of concern (MEC). This prompted enrollment of Wood Hollow into the Military Munitions Response Program as a legacy MEC-impacted site.

Starting in 2010, the UTARNG partnered with Parsons, a company specializing in munitions and ordnance remediation, to continuously assess Wood Hollow's footprint and accordingly restore the site. UTARNG also worked alongside Utah's Department of Environmental Quality (DEQ) and stakeholders in the Restoration Advisory Board (RAB), such as property developers, municipal representative, landowners, and mining company to ensure cleanup success.

Fieldwork commenced in 2014. The Utah Army National Guard, with approval from DEQ, completed remediation of Wood Hollow in the spring of 2017. These efforts have earned UTARNG a 2017 Secretary of Defense Environmental award for environmental restoration.

Initially, field crews cleared 258 acres designated as the Munitions Response Site (MRS). UTARNG and Parsons reassessed the landscape based on significant density of MEC and munitions debris (MD). They redefined the MRS boundaries and expanded the area of interest to 1,200 acres. The field crews systematically isolated where MEC/MD was present and where it was absent, narrowing the scope to 656 acres. As a result, a final site solution plan was presented to DEQ and the RAB.

The three-part proposal used statistical methods to delineate a risk-based strategic approach: Areas with high density MEC/MD require cleanup; areas with no MEC/MD require no further action; and areas with moderate density MEC/MD do not warrant 100 percent cleanup but risk and remediation will be assessed based on the parcel's future proposed use.

Once approved, this plan ultimately led to UTARNG's cleanup success--a 95 percent confidence level that there is less than 0.1 MEC per acre in areas zoned for residential and commercial use and 1 MEC per acre for undeveloped tracts.

"The Utah Army National Guard's risk-based approach to remediation and the metrics established for achieving MEC recovery will prove valuable for any military installation faced with land impacted by legacy operations," said Col. Tyler B. Smith, construction and facilities management officer for the UTARNG.

UTARNG's collaboration with Parsons also yielded another valuable methodology for other sites in need of restoration. Conventional digital geophysical mapping technology using magnetic imaging was rendered useless at Wood Hollow thanks to magnesium and other metals in the rough terrain. This, too, meant typical cart transport was impossible to deploy.

Parsons developed a modified mining detection unit called the Parsons Digital Mapper, which looked like a metal detector. The handheld tool allowed field crews to adjust the background interference for magnetic sensing based on the soil composition. It also allowed field crews to have continuous data processing, giving quicker identification of sites of concern.

The Parsons Digital Mapper, which allowed one person to cover large stretches of ground, helped UTARNG avoid false positives and futile excavations, ultimately saving money and minimizing time and effort.

Overall, 81 MEC items and 70,000 munitions debris items were recovered. MEC recovered was detonated onsite while MD recovered was taken for recycling. Several rounds of MEC from World War I were retained and certified as safe by the State Historic Preservation Office to be displayed as military artifacts.

Now that Wood Hollow has been remediated, the UTARNG will continue to ensure conservation measures using Camp Williams' Army Compatible Use Buffer (ACUB). The goal of this program is to assist with natural resource protection, fire management protection, and land preservation adjacent to UTARNG's military training facility. The program also will help establish recreation areas and fire response trails.

Having also incorporated public education and awareness campaigns stressing the importance of leaving items in place and contacting the UTARNG to address hazards during the course of Wood Hollow's restoration project, the UTARNG will continue education outreach with the local community for the next five years.

"The Utah Army National Guard is committed to being good stewards of our resources. We will continue to aggressively seek ways to improve our practices and reduce hazards," said Maj. Gen. Jefferson S. Burton, The Adjutant General for Utah.