Change in the length of the southern section of the Chandeleur Islands oil berm, January 13, 2011, through September 3, 2012

On April 20, 2010, an explosion on the Deepwater Horizon oil rig drilling at the Macondo Prospect site in the Gulf of Mexico resulted in a marine oil spill that continued to flow through July 15, 2010. One of the affected areas was the Breton National Wildlife Refuge, which consists of a chain of low-lying islands, including Breton Island and the Chandeleur Islands, and their surrounding waters. The island chain is located approximately 115–150 kilometers (km) north-northwest of the spill site. A sand berm was constructed seaward of, and on, the island chain. Construction began at the northern end of Chandeleur Islands in June 2010 and ended in April 2011 after 14 km of berm had been constructed. The berm consisted of three distinct sections based on where the berm was placed relative to the islands. The northern section of the berm was built in open water on a submerged portion of the Chandeleur Islands platform. The middle section was built approximately 70–90 meters (m) seaward of the Chandeleur Islands. The southern section was built on the islands’ beaches. Repeated Landsat and SPOT satellite imagery and airborne light detection and ranging (lidar) were used to observe the disintegration of the berm over time. The methods used to analyze the remotely sensed data and the resulting, derived data for the southern section are reported.