Insrastructure and Environmental Impacts Under Rising Sea Level, Intensifying Tropical Storms, and Population Pressure: Louisiana Coastal Plain

Harry H. Roberts
Coastal Studies Instutute, Louisiana State University, Baton Rouge, LA

As population pressure impacts our coasts in the framework of rising sea level and projected climate warming, the coastal plain of Louisiana is the largest potential disaster area along the US shoreline. The low-lying landscape of coastal Louisiana is the product of delta-building over the Holocene by one of the World’s great rivers, the Mississippi. Human intervention has altered the river-delta system by (1) construction of dams (38,000), (2) building of levees and revetments (1600 km), (3) construction of pipeline and access canals, (4) fluid and gas withdrawal associated with coastal plain oil and gas fields, and (5) salt water intrusion. Natural processes of subsidence and storm impacts have added to the vulnerability of man’s infrastructure and coastal wetlands under projected climate warming and sea level rise. Since the 1960s over 4000 sq km of wetlands have been lost. This trend could increase. Hurricanes Katrina and Rita alone impacted 3050 of over 4000 offshore oil and gas platforms and 35,400 km of the northern Gulf’s 53,100 km of pipelines. Katrina destroyed 46 platforms while Rita destroyed 69. The combined economic impact on oil and gas production was $11.8 billion. Katrina also caused significant wetland loss east of the Mississippi River. Climate warming and population increase will also increase coastal hypoxia. This condition arises from agricultural runoff and subsequent nutrient loading of our coastal waters. Over 4000 sq km of inner shelf was impacted by hypoxia in 2007. Future expansion of agricultural areas in the Mississippi River drainage basin in response to warming and population pressure will increase nutrient runoff and expand hypoxic conditions into our productive bays affecting valuable fisheries (oysters and shrimp).

AAPG Search and Discover Article #90078©2008 AAPG Annual Convention, San Antonio, Texas