Monitoring Groundwater Sample Clauses

Monitoring Groundwater. Groundwater is monitored in or near areas of groundwater contamination that might adversely affect surface water quality (Figure 2). Contaminated groundwater emerges to surface water before leaving the Central OU. DOE will maintain a network of groundwater monitoring xxxxx to assess the potential effects of contaminated groundwater on surface water quality. These xxxxx and sampling criteria are identified in Table 2 and shown in Figure 1 with the following well classifications: • Area of Concern (AOC) Xxxxx: Located within a drainage and downgradient of a contaminant plume or group of contaminant plumes. These xxxxx are monitored to determine whether the plume(s) may be discharging to surface water. • Sentinel Xxxxx: Typically located near downgradient edges of contaminant plumes, in drainages, and downgradient of groundwater treatment systems. These xxxxx are monitored to determine whether concentrations of contaminants are increasing, which could indicate plume migration or treatment system problems. • Evaluation Xxxxx: Typically located within plumes and near plume source areas, or in the interior of the Central OU. Data from these xxxxx will help determine when monitoring of an area or plume can cease. A subset of these xxxxx is located in areas that may experience significant changes in groundwater conditions as a result of closure activities.