Modeling of a Groundwater Circulation Well Removal Action Alternative

This paper presents the basis for using groundwater circulation wells (GCWs) for removal actions focused on contaminated domestic water supplies. A properly placed GCW could be used to pretreat water before it enters a domestic well. Commercial software was used to develop a model for GCWs installed at a Nebraska Superfund site to perform a feasibility study of a GCW-based removal action. Deterministic capture zone analysis provided guidance for locating vertically installed GCW up-gradient of an existing domestic well at the site. A deviation of up to 7.6 m off-center of the hydraulic gradient may be permissible. A GCW flow rate range to provide a sufficiently large recharge zone to protect a typical domestic well was identified for the site. Stochastic analysis indicated that the system was sensitive to horizontally variable hydraulic conductivity. Modeling results indicate that a GCW may both reduce contaminant mass in the aquifer, and act as a water supply replacement alternative to point of use treatment systems.