Extent and Degree of Shoreline Oiling: Deepwater Horizon Oil Spill, Gulf of Mexico, USA

TLDR

The 2010 Deepwater Horizon spill oil was documented on 1,773 km of Gulf of Mexico shoreline, and the cleanup program was managed under the systematic Shoreline Cleanup Assessment Technique (SCAT) to guide decisions. Cleanup activities were authorized on 660 km of beaches (73.3 %) and up to 71 km of marshes (8.9 %), and will continue until all oiled segments meet habitat‑specific endpoints. Beaches, marshes, and other shoreline types accounted for 50.8 %, 44.9 %, and 4.3 % of the oiled shoreline, and one year after the spill oil persisted on 847 km (mostly lightly oiled) and two years later on 687 km, with heavily oiled stretches falling from 360 km to 22.4 km and then to 6.4 km.

Abstract

The oil from the 2010 Deepwater Horizon spill in the Gulf of Mexico was documented by shoreline assessment teams as stranding on 1,773 km of shoreline. Beaches comprised 50.8%, marshes 44.9%, and other shoreline types 4.3% of the oiled shoreline. Shoreline cleanup activities were authorized on 660 km, or 73.3% of oiled beaches and up to 71 km, or 8.9% of oiled marshes and associated habitats. One year after the spill began, oil remained on 847 km; two years later, oil remained on 687 km, though at much lesser degrees of oiling. For example, shorelines characterized as heavily oiled went from a maximum of 360 km, to 22.4 km one year later, and to 6.4 km two years later. Shoreline cleanup has been conducted to meet habitat-specific cleanup endpoints and will continue until all oiled shoreline segments meet endpoints. The entire shoreline cleanup program has been managed under the Shoreline Cleanup Assessment Technique (SCAT) Program, which is a systematic, objective, and inclusive process to collect data on shoreline oiling conditions and support decision making on appropriate cleanup methods and endpoints. It was a particularly valuable and effective process during such a complex spill.