Shoreline Change History of Louisiana’s Gulf Shoreline: 1800s to 2005

Louisiana’s Gulf of Mexico shoreline is losing land. Over the past century, the erosion rate has progressively increased, threatening the health of coastal Louisiana. Through use of historical maps, satellite imagery, and aerial photography, experts mapped the patterns and rates of shoreline change. The gulf shoreline was divided into 80 reaches based on the geomorphology, change trends, existence of man-made structures, and/or a combination of these factors. The average historical rate (greater than 100 years) of shoreline change is -9.0 feet per year. The average long-term rate (greater than 50 years) of shoreline change is -14.0 feet per year. Over the past decade, shoreline change rates have accelerated to
–27.0 feet per year. Hurricane Katrina in 2005 accelerated the near-term rate (±1 year) of erosion to -189.9 feet per year. The highest rates of erosion were found along the Mississippi River Delta barrier islands of Isle Derniers, Timbaliers, and Chandeleur, with some areas eroding more than 600 feet. Beach nourishment, dune construction, and back-barrier marsh creation were the only project types that built new land and reversed gulf shoreline erosion.

Courtesy of Luis A. Martinez.