1) A study evaluated the effectiveness of a creosote containment system (SBS) at a former wood treating facility using multiple techniques including critical gradient analysis, dye tests, TarGOST borings, and CPT. 2) The analysis found that low river stages created sufficient upward gradients to mobilize NAPL in river sediments, allowing it to potentially circumvent the SBS. 3) Data characterized the lateral and vertical extent of NAPL, finding it may be circumventing the ends of the SBS and possibly migrating under areas where the SBS was not driven deep enough.