Subslab Depressurization System
In 1999, the Air Force installed active subslab depressurization systems in 12 apartment buildings at Heritage Estates Lowry Heightsapartment complex and one single family residence, which overlies the plume north of the base boundary. The system at Lowry Heights consists of 54 centrifugal fans that create negative pressure beneath the building foundation slabs, preventing groundwater-derived VOCs from migrating into overlying structures.
In addition to the Lowry Heights systems, CDPHE requires that active subslab systems be installed in all new construction built over the groundwater plumes at Lowry. These subslab systems are similar to those used throughout metro Denver for radon mitigation, and will be installed by each home builder. The systems create a low pressure zone beneath the house and vent to the outside. More information on the State Enviromental Covenant requiring the residential subslabe systems for certain areas at Lowry cam be viewed on the CDPHE website.
The requirement for the subslab depressurization system was recorded with the property deed by the covenant, which will appear with the title documents for those properties above the plumes. The covenant also has several other requirements such as no drilling of wells or use of the groundwater. The covenant requires notification to the State upon sale or lease of the property and upon application of any building permit. The covenant will run with the property until the groundwater remediation is complete and final approval has been issued by CDPHE. A fact sheet about the depressurization systems and covenants are provided to potential buyers of property over the groundwater plume.