Management of Treatment, Storage, & Disposal Facilities - Key Terms

Aquifer refers to the underground layer of permeable materials (such as rocks, gravel, or sand) through which the groundwater flows.

Containment layer refers to a layer of the containment system. For example, the containment layers for a waste pile could include two layers of an impermeable lining and a concrete dike that surrounds it.

Containment system refers to a system of barriers installed to prevent a hazardous waste spill from being released into the environment (for example, tanks, liners, dikes, or berms).

Floodplains are areas, generally near streams or rivers, that may flood during periods of heavy rain, snow, or other precipitation.

Groundwater refers to the water held in the uppermost aquifer (closest to the surface). Groundwater is stored and flows around the rocks and other materials. The contamination of groundwater is one of the primary concerns of the RCRA law.

Salt domes are dome-shaped formations within sedimentary (layered) rock. These domes are made up of minerals (primarily salt) that have been pushed upward into the rock layer. Salt domes often form pockets where petroleum and natural gases may collect.

Seismic faults are breaks in Earth's surface where earthquake activity is more likely to take place. These breaks are called "seismic fault lines," or simply "fault lines."

To learn more about RCRA safety standards visit our RCRA Refresher Online Training web page.