Exit Strategy Support
Pump-and-Treat (P&T) technology is commonly used to remedy groundwater contamination. Management of the P&T remedy requires quantifying its performance over time, because P&T remedies frequently experience decreases in contaminant removal over time, often due to the complex nature of the site geology and the nature of the contamination.
The GALEN and PLATO tools provide analytics that support management decisions on when to transition to a new remedy or initiate closure of the P&T remedy. These tools were developed based on guidance on P&T exit strategies provided by Truex et al. (2015). The rapid analytics provided in these tools support decisions regarding P&T system optimization, P&T transition to natural attenuation, and complementary technologies that can accelerate the transition to natural attenuation.
Decision elements for the P&T performance assessment include:
- Contaminant concentrations and trends
- Contaminant mass discharge from source areas or at selected plume locations
- Aquifer attenuation capacity
- Estimated future plume behavior and time to reach remedial action objectives for the site
- Information on P&T system design, operation, and cost
GALEN (Groundwater AnaLytics for the ENvironment) can provide access to multiple sources of water level data through a single access portal. It includes tools for visualization and analysis of groundwater level and flow direction over time, key elements in supporting site characterization and enhancing remediation system design and performance monitoring.
GALEN enables rapid visualization of groundwater level data, providing filters for well selection based on well type, location, and geologic unit for well completion. Data visualization options include:
- Raw data. Plots data with and without outliers, based on user selection.
- Running median. Plots data with a smoothing method that uses the median value within a time window centered around each time point of interest.
- Gaussian (31- and 181-day). Plots data with a kernel smoothing method using a Gaussian weighting function and a 31-day or 181-day time window centered on the period of interest.
- Groundwater flow directions. Quiver plots can be generated to rapidly show groundwater flow directions over the time window of interest.
PLATO (PLume Analysis TOol) analyzes groundwater data to assess contaminant plume behavior, providing a consistent framework to quantify groundwater contaminant plume dynamics that support remedial decisions. PLATO implements data-driven, quantitative analyses based on standard statistical methods and published guidance from the U.S. Environmental Protection Agency and U.S. Geological Survey.
PLATO enables rapid visualization of groundwater concentration data, providing filters for well selection based on well type, location, and geologic unit for well completion. In addition, PLATO allows for rapid selection of wells that have had groundwater concentrations sampled within the same time period. This is accomplished by organizing well data based on temporal coverage, with histograms providing a visual indication of the consistency in sampling times.
- Single well analysis. Concentration data can be plotted with linear and exponential trend lines, regression statistics, and confidence and prediction intervals for a single well.
- Multiple well analysis. Concentration data can be plotted with linear and exponential trend lines, regression statistics, and confidence and prediction intervals that are representative of average concentrations for the selected wells, using either equal weighting or area-based weighting to reflect plume contaminant mass.
- Well-pair analysis. Using flow direction and gradient components from GALEN, concentrations are plotted between an upgradient well and downgradient well.