Geologic Framework and Processes of the Lake Pontchartrain Basin

Lake Pontchartrain and adjacent lakes in Louisiana form one of the larger
estuaries in the Gulf Coast region. The estuary drains the Pontchartrain Basin
(at right), an area of over 12,000 km2 situated on the eastern side of the
Mississippi River delta plain. In Louisiana, nearly one-third of the State
population lives within the 14 parishes of the basin.

Over the past 60 years, rapid growth and development within the basin, along
with natural processes, have resulted in significant environmental degradation
and loss of critical habitat in and around Lake Pontchartrain. Human activities
associated with pollutant discharge and surface drainage have greatly affected
the water quality in the lake. This change is evident in the bottom sediments,
which record the historic health of the lake. Also, land-altering activities
such as logging, dredging, and flood control in and around the lake, lead to
shoreline erosion and loss of wetlands.The effects of pollution, shoreline
erosion and wetland loss on the lake and surrounding areas have become a major
public concern.

To better understand the basin's origin and the processes driving its
development and degradation requires a wide-ranging study involving many
organizations and personnel. When the U.S. Geological Survey began the study of
Lake Pontchartrain in 1994, information on four topics was needed:

-Geologic Framework, or how the various sedimentary layers that make up
the basin are put together

-Sediment Characterization, that is, what are the sediments made of, where
did they come from, and what kinds of pollutants do they contain

-Shoreline and Wetland Change over time

-what are the processes that control Water Circulation

[Summary provided by the USGS.]