... important to understand contaminant transport to ensure ©2001 CRC Press LLC In Situ In Situ Figure Funnel-and-Gate SystemTM using gates in series that the contaminants remain in the upper portion of ... barriers including continuous trenching, excavation and backfilling, overlapping caissons, soil mixing, and hydrofracturing Each of these is discussed in more detail below Continuous Trenching Continuous ... monitoring point within the treatment gate to verify that the treatment gate is effective in removing these compounds prior to the water exiting the gate This monitoring point is shown in Figure 11...