COASTAL LAND LOSS IN LOUISIANA DISPROPORTIONATELY AFFECTS NATIVE AMERICAN TRIBAL GROUPS
Land loss is pervasive in southern Louisiana, but GIS analysis of tribal lands reveals that they are turning to water at rates greater than the average. For example, the area of Terrebonne Parish occupied by the Grand Caillou/Dulac Band of Billoxi-Chitimacha-Choctaw comprises 295 km2. Topographic maps from the 1940s show this area as marshland, drained by numerous bayous, with three distinct lakes (Boudreaux, Gero, and Quitman) By the 1980s, the lakes had expanded and merged to form a single water body; numerous artificial channels (including the 30-mile Houma Navigation Canal) had been dredged; and land loss rates were on the increase. Landsat images spanning 1996 to 2017 show that in 1996 the tribal area was 88% land and 12% water. By 2017 that had changed to 81% land and 19% water. Computed slightly differently, 9% of the 1996 land area had turned to water by 2017. USGS data for the same time period (Couvillon et al. 2017, SIM 3381) show that for Terrebonne Parish as a whole, 3.1% of the land had turned to water; and for the entire coastal Louisiana region, the loss over that time period was 2.8%. Thus the rate of loss of this tribal group's land in the past two decades is about 3 times higher than the background rate. This underscores the extreme vulnerability of indigenous groups in the delta.