We read about Venice sinking into the sea, but New Orleans is sinking right here at home. Most of North America is built on bedrock, but New Orleans is built on Mississippi River silt, which is settling, due to gravity. This settling has been going on for a long time, but lately the surface has been dropping fast. This is due to the levees, which were built to stop the Mississippi from flooding. However, the floods used to deposit new layers of soil on the land. Without this process, the city has become 6 to 20 inches lower in the past 20 years.
read more