PRIMER

THE COLORADO WATER QUALITY CONTROL COMMISSION ISSUED A RULEMAKING FOR CLASSIFICATION AND SITE-SPECIFIC STANDARDS IN GROUND WATER (OPERABLE UNIT 5) AT THE FORMER LOWRY AIR FORCE BASE, DENVER AND AURORA, COLORADO

Lowry Assumption, LLC (LAC) has implemented groundwater remediation at the Former Lowry Air Force Base (Lowry AFB) since 2004.  The final groundwater remedy for Operable Unit 5 (OU5) was set forth in the Phase 2 Corrective Action Plan for Groundwater Cleanup at Lowry (Phase 2 CAP) that was vetted through a public comment and public meeting process.  The Phase 2 CAP was approved by the Colorado Department of Public Health and Environment (CDPHE) in February 2007.  

The Phase 2 CAP for OU5 established Remedial Action Objectives (RAOs) to provide the regulatory framework necessary to achieve eventual closure of the ground water plumes at the former Lowry AFB.  In those RAOs, the selected remedy for addressing trichloroethylene (TCE) contamination in four ground water plumes associated with the former Lowry AFB consisted of direct injection of a chemical oxidant (potassium permanganate) into the ground water plumes to destroy the TCE in place.  Overall the selected remedy was very effective in destroying contaminant mass in the source areas and ground water plumes as well as reducing the areal extent and the concentrations of TCE within those plumes.  Eventually the selected remedy became less effective despite a significant increase in the amount of chemical oxidant injected.  The reduced effectiveness of treatment results from geologic conditions that make it difficult to achieve contact between the chemical oxidant and the remaining TCE mass.  Thus, the remedy has reached its technically practicable limits while groundwater contaminants remain above the applicable Colorado Basic Ground Water Standard.  In addition, other treatment technologies suffer from the same limitations or have other limitations that make them impractical.

In anticipation that the selected remedy, or other applicable remedies might not attain the applicable Colorado Basic Ground Water Standard, the RAOs set forth in the approved Phase 2 CAP allowed for the option to pursue site-specific standards for groundwater in order to achieve closure.  In accordance with those RAOs, LAC petitioned the Colorado Water Quality Control Commission for applicable site-specific standards for groundwater associated with the Former Lowry AFB, including plumes extending beyond the boundaries of the Former Lowry AFB.  LAC submitted a petition for classification and site-specific standards for groundwater at Lowry to the Water Quality Control Commission in October 2013.  LAC held a public meeting on February 20, 2014 to discuss the status of groundwater remediation and the proposed site-specific standard process with the Lowry Community.  LAC submitted its Pre-Hearing Statement to the Water Quality Control Commission on March 4, 2014.  A public rulemaking hearing on the proposed site-specific standards was held by the Water Quality Control Commission in May 2014.  The rulemaking hearing resulted in the approval of site-specific groundwater standards for TCE and 1,4-dioxane.   In July 2014, site-specific standards for TCE and 1,4-dioxane in groundwater at Lowry were promulgated in Section 42.7(54) of Regulation 42 - Site-Specific Water Quality Classifications and Standards for Ground Water (5 CCR1002-42:42.7(54)). 

Information regarding the progress of groundwater remediation at the Former Lowry AFB can be found on the following websites: 

The U.S. Air Force Civil Engineer Center administrative record: http://afcec.publicadmin-record.us.af.mil

The CDPHE website: http://www.colorado.gov/cs/Satellite/CDPHE-HM/CBON/1251616142313

Environmental documents are available for review and study by the public at the CDPHE HMWMD Records Center located at 4300 Cherry Creek Drive South, Denver.  For an appointment to review documents at the HMWMD Records Center, contact personnel there by telephone at (303) 692-3331 or by e-mail at comments.hmwmd@state.co.us.  A project library is also maintained by LAC in its office located at7290 East 1st Avenue, Denver; an appointment to review documents at the project library can be made by calling (303) 972-6633.

If you have any questions about the site-specific standards or would like more information about the status of groundwater remediation at the Former Lowry Air Force Base, please contact: 

 

Lowry Assumption, LLC
7921 Southpark Plaza, Suite 109
Littleton, CO  80120
(303) 972-6633 (phone)
 
 
Andrew Ross
Water Quality Control Division
Colorado Department of Public Health and Environment
4300 Cherry Creek Drive South
Denver, CO 80246
 
(303) 692-3395 (phone)
 
 
Jeannine Natterman
Hazardous Materials and
Waste Management Division
Colorado Department of Public Health and Environment
4300 Cherry reek Drive South
Denver, CO 80246
 
(303) 692-3303 (phone)