Real-time (short-term) air monitoring at IHC CDF measures emissions of particulate matter (PM) and naphthalene. This is one of four real-time air monitoring stations located on the perimeter of the CDF . Real-time air monitoring informs current conditions at the site, and is used to determine the need for air emissions control actions. [Source: USACE]Each real-time air monitoring station consists of two continuously operating real-time monitors. Shown here is a hybrid ambient particulate monitor for measuring PM10 and PM2.5. [Source: USACE]Each real-time air monitoring station consists of two continuously operating real-time monitors. Shown here is a two-part open-path ultraviolet differential optical absorption spectrometer (UV-DOAS) to monitor naphthalene. [Source: USACE]Ambient (long-term) air monitoring is another type of monitoring that is used to assess long-term trends of air quality at the site and local vicinity. The long-term air data show that the surrounding community is not adversely impacted from the CDF emissions. This is one of four ambient (long-term) air monitoring stations located at the CDF. [Source: USACE]An additional ambient (long-term) air monitoring station is located south of the CDF at the East Chicago High School. [Source: USACE]Ninety-six groundwater extraction wells surround the perimeter of the site. These extraction wells are connected to a centralized computer system that regulates groundwater levels within the site. The wells maintain a lower groundwater elevation on the interior of the site than on the exterior of the site, separated by a below ground slurry wall, preventing groundwater from leaving the site. The entire system of wells, pipes, pumps, etc., is designated the Gradient Control System (GCS). [Source: USACE]Historically, when a barge with dredged material was located at the CDF, the air was monitored near the dock using a photoionization detector (PID). This PID monitoring took place daily prior-to and during dredging. Conducting PID monitoring at the dock area provided data on the effects of sediment activity at the barge on emission levels for worker and community safety. [Source: USACE]Seven pairs of piezometers are used to monitor groundwater levels beneath and adjacent to the CDF perimeter dike. Each pair of piezometers is located on the top and at the toe of the dike. The piezometer data inform conditions of dike stability with respect to groundwater elevation. A technician monitors the groundwater level at a piezometer. [Source: USACE]Well testing is conducted periodically to assess continued performance of gradient control system wells. Well drawdown testing is performed for an extraction well, part of the gradient control system (GCS). [Source: USACE]
