Model-Predicted Groundwater Circulation Well Performance

Abstract

Groundwater circulation well (GCW) techniques are an innovative remedial technology that may effectively remediate contaminated groundwater in areas unfavorable to more traditional technologies. Traditional pump-and-treat systems may be problematic where concentrated hot spots of contamination are present, aquifer drawdown due to remedial activities is unacceptable, surface discharge of treated groundwater is unwanted, or property acquisition is challenging. The vertical component of groundwater flow induced by GCW systems presents a new challenge to practitioners evaluating their potential performance. Modifications were made to two familiar pump-and-treat analysis tools—capture zone type curves and MODFLOW numerical groundwater flow modeling—to predict site-specific effectiveness of GCW technologies. These techniques were used to predict the GCW treatment area dimensions, which included the capture zone, recharge zone, and circulation cell diameter. Additionally, GCW design parameters including GCW spacing, screen length, screen placement, and circulation flow rate were determined. The state of the practice is to use these predictive tools to design an instrumentation scheme that can effectively evaluate the performance of GCW systems during full-scale pilot testing.