Officials with the Wisconsin DNR said that they will be carefully monitoring groundwater data when the Army shuts down active groundwater cleanup at Badger Army Ammunition Plant later this month. However, some residents with deeper bedrock wells believe that they are not adequately protected by the current groundwater monitoring system and that the WDNR should reinstate private well testing for certain homes near the plant. The concerns were raised at a public meeting on groundwater held at the River Arts Center in Prairie du Sac on December 11.
“While the Army and WDNR have approximated the boundaries and speed of groundwater contaminant movement in the upper unconsolidated aquifer, (we) haven’t seen any similar study of the deeper bedrock aquifer,” residents pointed out. “We need more information, not less – testing of residential bedrock wells should be reinstated.”
Rural neighbors also urged the WDNR to include irrigation wells in their analysis. There are at least 8 irrigation wells near and even on top of the southern groundwater contaminant plume. The Army has not tested these wells for at least 20 years, an area farmer said.
If a groundwater Enforcement Standard is exceeded in a private well near Badger, the WDNR said that residents will be provided with an alternate water source. If the well exceeds the Enforcement Standard a second time, the well will be replaced. To date, the Army has replaced 5 private wells.
Lori Huntoon, a hydrogeologist who presented technical comments on behalf of CSWAB, questioned why the WDNR recently approved a significant reduction of 75% in sampling of residential water supply wells near Badger without any public outreach or discussion.
“Until recently, the Army and WDNR had routinely allowed for public comment regarding actions at the former plant,” Huntoon asked. “What was the rationale for this modification without allowing for public input, especially when this change impacts so many residents?”
Badger is the source of three distinct areas of groundwater contamination known as plumes. These plumes flow from the southern, central and northeast portions of Badger. The principal contaminants of concern are solvents and explosives. A map showing the approximate plume locations may be found online at www.cswab.org/resources/maps/.
The Propellant Burning Ground (southern) Plume:
The pump-and-treat system at Badger was designed to capture groundwater contaminants and protect public and private wells south of the plant. The Army will soon end all active groundwater remediation, proposing instead that natural attenuation processes such as dilution, degradation and dispersion will improve groundwater quality.
As a remedy, Monitored Natural Attenuation (MNA) has not been approved at Badger. The WDNR said that the Army must first demonstrate that plume boundaries are stable or receding. There must also be clear evidence that contaminant plumes are not expanding or migrating, WDNR emphasized. Monitoring will be conducted to evaluate the effectiveness and ability of this approach to meet groundwater standards. Groundwater data must show that the concentration for each contaminant is declining over time, WDNR added.
Army contractors explained that they plan to ask the WDNR for permission to shut down active groundwater cleanup as early as this month. In anticipation of the shut-down, the Army will be installing a number of additional groundwater monitoring wells. So far, 6 monitoring wells have been installed near the Propellant Burning Grounds which is considered the source of groundwater contamination that flows south of Badger near the Village of Prairie du Sac. Another 24 monitoring wells will be placed along the southern plant boundary and in the estimated center of the onsite plume.
Until it is clear that MNA is working, the WDNR has required the Army to maintain all groundwater extraction (cleanup) wells. They cannot be abandoned until WDNR expressly approves their removal, officials said.
The Deterrent Burning Grounds (northeast) Plume.
Army contractors also discussed a second groundwater contaminant plume near the northeast corner of Badger in the town of Merrimac. Testing by the Army has shown increasing trends in a groundwater monitoring well located approximately 625 feet from a residential well at Weigand’s Bay. The Army has reported increasing concentrations of the explosive 2,5-DNT in groundwater at levels approaching unsafe standards. Based on the estimated groundwater flow speeds, WDNR officials said that they do not anticipate that this contamination will reach this private well. The WDNR has required the Army to conduct annual testing of private wells nearby.
The Rocket Paste (Central) Plume.
The Army was asked about the source of the third groundwater contaminant plume which has reached a residential area near Gruber’s Grove Bay. Army contractors said that a drainage ditch coming from one of the former buildings was sampled and excavated, and it appears that this ditch drainage point may have been the source, but this has not been confirmed.
State legislative staff in attendance asked why there is no requirement for groundwater well monitoring within the central plume itself, similar to the other two plumes. The WDNR said that this plume is not included in the facility-wide cleanup requirements for Badger. So far the Army has continued to monitor the area so no official letter requiring monitoring has been issued. The WDNR added that it would be covered under the state’s spills law.
CSWAB is encouraging the Army and WDNR to have another public meeting in the spring to keep the community informed. The group is currently fundraising to retain an independent professional hydrogeologist to review and interpret anticipated groundwater studies.
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