A combined Shewhart-CUSUM procedure with application to groundwater monitoring

A combined Shewhart CUSUM statistical process control procedure is being implemented at Savannah River Site for monitoring groundwater effluent concentrations. The procedure is being developed for the Environmental Monitoring Section and will be available to yield information on remediation performance in real-time for improved decision making. The method is outlined and an application given to monitoring trichloroethylene concentrations at a Savannah River Site point of compliance well. The combined charting methods incorporate the strengths of both charting methods. This intra-well comparison method will provide a visual tool for detecting both abrupt changes and increasing or decreasing trends in constituent concentrations