The funnel‐and‐gate ground water remediation technology (Starr and Cherry 1994) has received increased attention and application as an in situ alternative to the typical pump‐and‐treat system. Understanding the effects of heterogeneity on system performance can mean the difference between a successful remediation project and one that fails to meet its cleanup goals. In an attempt to characterize and quantify the effects of heterogeneity on funnel‐and‐gate system performance, a numerical modeling study of 15 simulated heterogeneous flow domains was conducted. Each realization was tested to determine if the predicted capture width met the capture width expected for a homogeneous flow domain with the same hulk properties. This study revealed that the capture width of the funnel‐and‐gate system varied significantly with the level of heterogeneity of the aquifer. Two possible remedies were investigated for bringing systems with less than acceptable capture widths to acceptable levels of performance. First, it was determined that enlarging the funnel and gate via a factor of safety applied to the design capture width could compensate for the capture width variation in the heterogeneous flow domains. In addition, it was shown that the use of a pumping well downstream of the funnel and gate could compensate for the effects of aquifer heterogeneity on the funnel‐and‐gate capture width. However, if a pumping well is placed downstream of the funnel and gate to control the hydraulic gradient through the gate, consideration should be given to the gate residence time in relation to the geochemistry of the contaminant removal or destruction process in the gate.

The funnel and gate remediation concept (Star and Cherry 1993) represents a promising, yet relatively under‐developed, technology for the passive control and in situ remediation of contaminated ground water. Effective design and implementation of such a system may, however, prove difficult under conditions of large or unpredictable variations in contaminant migration or ground water flow. Numerical modeling of two‐dimensional ground water flow has been used to predict the hydraulic performance of passive, straight, or winged funnel and gate configurations over a range of hydrogeologic and ambient ground water flow conditions. The results of these analyses were used to construct generic correlation diagrams relating upstream capture zone or gale through put to the barrier, gale, and aquifer characteristics. These diagrams serve as useful screening tools to (1) quantitatively estimate the capture zone of pre‐determined funnel and gale configurations, or (2) develop preliminary funnel and gale designs that will yield a desired capture zone, independent of aquifer characteristics.