Four Bayous Pass; Barataria Bay, LA

Barataria Bay, LA | 1999-Nov-24

Initial Notification: At approximately 3:15 AM on 24 Nov. 1999, a pipeline release occurred just east of East Grand Terre Island off Barataria Bay, Louisiana. The cause of the release is still under investigation. Between 850 and 1200 bbls of a deep well production oil was released. The oil was identified as MARS Blend, a relatively high sulfur, low asphaltene crude oil. The initial trajectory predicted the oil would move south of Four Bayous pass and sustained north winds would move most of the oil offshore. The winds were less than the forecast and the spill coincided with a spring tide (not the season Spring, but the description of the time in the tide cycle characterized by the greatest high and low tides, derived from spring up or rise). Much of the oil moved back into Four Bayous and Barataria Pass. The next morning. Heavy concentrations of oil were observed on shorelines and on water. The NOAA SSC participated in a morning overflight (pre-SCAT survey) on Thanksgiving morning to delineate oiled shorelines and surface oil. Heavy surface oil concentrations north of Grand Terre and south of Four Bayous Pass were identified and skimmers repositioned. Heavy oil was observed on the barrier islands of Barataria Bay. The barrier islands impacted were Elmer's Island, Grand Isle, Grand Terre, and East Grand Terre. The latter two were the heaviest impacted and the most remote (no road access). Stranded oil was heaviest near the passes and on the eastern end of each island. At least one marina at Grand Isle was impacted. By Friday (two days after the spill), overflights looked encouraging. Very little oil was visually observed on the beaches and on-water sheens were significantly reduced; unfortunately, most of the oil was buried by depositional sand and the lower tide level was preventing remobilization of stranded oil. The SCAT team used the aerial pre-SCAT survey to aid shoreline assessments since the heavily oiled beach areas were previously identified, but now mostly hidden by over-laying sand. SCAT was an essential element in the response and used by the Unified Command to define areas which required cleanup as well as monitoring cleanup activities to insure that the cleanup recommendations were both adequate and adhered to by field crews. More than 100 cleanup works were engaged in this response. Cleanup objectives and endpoints were developed within the SCAT organization. SCAT recommendations developed a balance between preserving beach sand (a valued state resource) and minimizing potential environmental threats. At the end of the day (Sunday, 28 Nov.), only five sites are still being cleaned. Of particular interest are a small marsh on the interior of East Grand Terre and a Gobi revetment (riprap) along the Conoco facility on the north side of Grand Isle (see Hotline #15 pictures, EGT and GIC, respectively). Both sites contain free oil. Both sites present unique cleanup problems. The interior marsh is highly isolated and composed of very soft sediments which restrict access without causing environmental injury. Each of the Gobi blocks is an Ïegg crate-like" structure with spaces which hold trapped fluid oil. USCG district 8.