Groundwater statistical methods have applications throughout the life cycle of environmental projects. Statistical analysis plays a major role in the stages of an environmental project life cycle: release detection, site characterization, remediation, monitoring, and closure. Although individual projects may vary in their progression through these stages, groundwater statistical tests can support decision making, regardless of how the project is defined. Statistical analysis allows for important questions to be asked and examined. Such include:
• What are the background concentrations?
• Are concentrations greater than background concentrations?
• Are concentrations above or below a criterion?
• When will contaminant concentrations reach a criterion?
• Is there a trend in contaminant concentrations?
• Is there seasonality in the concentrations?
• What are the contaminant attenuation rates in wells?
• How do contaminant concentrations change with distance from the source area?
• Is the sampling frequency appropriate (temporal optimization)?
• Is the spatial coverage of the monitoring network appropriate (spatial optimization)?
These questions relate one to another in the context of specific groundwater evaluation objectives that may be familiar to practitioners during various project life cycle stages. For instance, questions 3 and 4 assess contaminant concentrations with respect to criteria (such as regulatory standards). Questions 5 and 6 evaluate temporal trends in data sets. Questions 7 and 8 assess temporal and spatial rates of change for contaminants. Questions 9 and 10 evaluate if the frequency of sampling and spatial coverage of wells are appropriate, leading to an optimal monitoring program.
These questions serve as a bridge to connect life cycle activities with relevant statistical tests and methods. Using statistical analysis with these tests and methods, can address the practical applications, challenges, and misapplications associated with groundwater projects.