Coastal Louisiana contains 40% of the nations wetlands. These wetlands are the direct result of repeated shifts in the course of the Mississippi River over the past 7000 years. The resulting landscape is a complex network of abandoned distributaries and beach ridges separated by marshlands. Until the early 1900s there was an overall net increase in the size of the Louisiana coastal plain. Since then, this trend of landbuilding has reversed and coastal Louisiana is losing land at a high rate. Causes for this loss include, but are not limited to, geologic factors such as faulting, subsidence, depth to Pleistocene, geomorphology, differences in the engineering properties of the various environments of deposition, sediment age, and hydrologic setting. Manmade factors responsible for land loss such as dredging of location canals and navigational waterways, as well as levee construction, also account for a significant portion of the total land loss.