Environmental clean-up at Walker Lake, Nevada
By Chuck King
HAWTHORNE ARMY DEPOT, Nev. — Hawthorne Army Depot, the Army Corps of Engineers Sacramento District, the Army Environmental Command and contractors from Northwind Inc., TLI Solutions, NAEVA Geophysics and the Munitions Management Group have partnered together to perform a partial cleanup operation at the south end of Walker Lake in Mineral County, Nevada.
The initial action began in November 2011 and was completed in April 2012 at a cost of $5.2 million. Lt. Col. Bill Johnson, HWAD commander, has been pleased with the process and the outcome of this project.
"This action has proven that the United States Army shows concern for our environment and will continue to press forward to remediate those sites and areas that are contaminated," said Johnson.
A time-critical removal action was conducted in an attempt to locate and remove a large number of the munitions that were fired by the Navy from the 1940s through the 1970s utilizing the Walker Lake Test Range Impact Area, Rocket Depth Charge Test Range and the Rocket Test Range. These munitions ranged in size from 2.75-inch rockets up to 5-inch Zunis and Antisubmarine Rockets. In addition, depth charges, including the 7.2-inch Hedgehog and other unidentified prototype munitions may have been tested at the range. The three ranges have been inactive for 40 years and are not needed to accomplish the depot's current mission.
The munitions were fired from buildings on the depot onto impact areas that lie within the lake. The southern extent of Walker Lake straddles the northern boundary of the depot and as the lake has receded over the years, more and more of the unexploded ordnance, or UXO, has become exposed. Most of the impact areas lie on land owned by the Bureau of Land Management or the state of Nevada and coordination with both entities was required prior to the removal action.
Previously, in 1974, a clearance action was taken and over 6,000 pieces of munitions and munitions debris weighing more than 75 tons were identified and removed.
The scope of the recent contract required Northwind/TLI and its subcontractors to clear munitions to a depth of two feet on land and two feet below the surface of the water over a 40 acre area.
The effort to clear munitions from the area was plagued by high winds, blowing dust and subfreezing temperatures. Despite these setbacks, 638 pieces of UXO have been destroyed in place and more than 65 tons of munitions debris have been identified, sorted and sent for recycling.
In addition to the removal action, a 6.5 mile fence was erected around the impact area and the northern part of HWAD. The fence serves two purposes. The first is to keep unauthorized personnel out of the impact area on the land side and the second is to keep a wild horse herd from wandering onto Highway 95.
After the completion of the removal phase, a remedial investigation will take place to determine what further action is required.
As the lake recedes from upstream diversion for agriculture, more UXO will become visible and further removal action will be required. The Nevada Division of Environmental Protection is aware of the ongoing activity and continues to support HWAD and its efforts to ensure the safety of the citizens of Mineral County.
During the process, some Native American remains were discovered on BLM land by clearance personnel and stabilized by the Bureau of Land Management, Walker River Paiute Tribe and HWAD. BLM archeologists believe the remains are between 1000 and 1500 years old.
Additionally, several piles of inert munitions debris have been accumulated over a period of time and are scheduled to be classified, sorted and recycled. The AEC has agreed to fund the initial removal action of this munitions debris.
As a Joint Munitions Command installation, Hawthorne Army Depot is an archive site for storing slow-moving ammunition and stocks awaiting demilitarization. HWAD provides high desert training facilities for military units. As the designated site for long-term storage of reused industrial plant equipment, Hawthorne receives, stores and accounts for all IPE.
From its headquarters at the Rock Island Arsenal, JMC operates a nationwide network of conventional ammunition manufacturing plants and storage depots, and provides on-site ammunition experts to U.S. combat units wherever they are stationed or deployed. JMC's customers are U.S. forces of all military services, other U.S. government agencies and allied nations.