Assessment of multi-gate interceptors equipped with baffles in contaminated aquifers

Funnel-and-gate structures with three gates, two funnels (collinear with gates), and two perpendicular flow-directing vanes (baffles) were assessed for capturing contaminated groundwater in a hypothetical unconfined aquifer. Simulated structures, anchored into an underlying aquiclude, were 35 m wide. One 5-m wide gate occupied the center, and two 3-m wide gates occupied the ends, of each structure. Both homogeneous and heterogeneous (with respect to hydraulic conductivity) aquifers were modeled, with baffles at various positions along funnels in alternative configurations. A contaminant transport model, accounting for advection and hydrodynamic dispersion, tested the capability of various structures for capturing contaminant plumes. Based upon modeling results: (1) structures with baffles performed up to 17% better (homogeneous case), but also up to 48% worse (heterogeneous case), than structures without them; (2) the most effective baffles generally occupied interior portions of funnels; and (3) small (1-m) shifts in the locations of baffles resulted in up to a 33% increase (homogeneous case) in remediation timeframe.