Link to USGS home page
Coastal and Marine Geology Program
Coastal & Marine Geology Program > St. Petersburg Coastal and Marine Science Center > Lake Pontchartrain Basin

Geologic Framework and Processes of the Lake Pontchartrain Basin

Lake Pontchartrain Basin Home
Field Methods
Topics of Investigation
Geologic Framework
Shoreline/
Wetland Change
Water Circulation
Publications
Satellite Imagery
Bonnet-Carré Spillway Event
Water Turbidity
Sea-Surface Temperature
1997 Algal Bloom
Project Contact:
Jack Kindinger

Shoreline/Wetland Changes

  Shoreline Erosion - Lake Pontchartrain: Click to view a larger version
Shoreline Erosion - Lake Pontchartrain
Shoreline Loss - Lake Maurepas
Shoreline Loss - Lake Maurepas: Click to view a larger version
To determine shoreline and wetland change, digital analyses of historical charts and aerial photographs were used. These were compared with recent surveys and charts. Scientists can use information on shoreline change over the past 100 years to predict areas of future change.

New Orleans Historic Growth
Classification of Land Loss:
Click to view a larger version
 
Shoreline erosion and wetlands loss are serious concerns in and around Lake Pontchartrain. Causes of loss involve a complex interaction between natural and human activities. Direct removal of land for canals, redistribution of material for development and other processes that alter hydrography create conditions of erosion, submergence and degradation of vegetation (see classification of land loss). In general, the utilization of Pontchartrain Basin's natural resources, steady population growth (see below) and land development over the past century have contributed to the shoreline and wetland loss that we see today. Natural subsidence, a result of dewatering in geologically young sediments, also contributes to the loss in currently unknown proportions.

Population Growth

  New Orleans Historic Growth
Historic Growth of New Orleans
From its beginnings over two centuries ago, New Orleans has grown consistenly in area and population. Its strategic position on the Mississippi River for security and trade made the city the seventh largest in the country by the early 1800's. Throughout the last two centuries, New Orleans has expanded to currently cover approximately 175 square miles with over one million people in the surrounding parishes.

New Orleans Parish Population
Parish Population Growth: Click to view a larger version
 
This growth has brought significant change to the environment in the Pontchartrain Basin. This change has been recorded in the sediments of Lake Pontchartrain, which receives drainage from the Basin and directly from the New Orleans area.

The sediments display a history of change in pollen assemblage, indicating a transition from hardwoods to clear-cut grasslands and agricultural fields. Trace metals concentrations in the sediments indicate an increase from background of industrial-related contaminants.

 
Expansion and Northward Migration: Sources - U.S. Census Bureau and the Louisiana Population Center. 1997 and 2020 figures are estimated.
 
In most recent times there has been a migration of population growth. Historically the south shore of Lake Pontchartrain has seen rapid development, whereas the marshlands and pine forests on the north shore have remained relatively intact. Over time, farmland had been encroaching on the lake from the north. With the construction of the Lake Pontchartrain Causeway across the lake and Interstate 10 along the eastern shore, accessibility to the north shore has been greatly improved. This accessibility has been reflected in a population shift, where growth in the parishes along the north shore has caught up and even surpassed that of the New Orleans area. This trend is expected to continue and changes in environmental parameters associated with development should have an impact on the conditions within the lake.

  top of page

Coastal & Marine Geology Program > St. Petersburg Coastal and Marine Science Center > Lake Pontchartrain Basin


FirstGov.gov U. S. Department of the Interior | U.S. Geological Survey
Center for Coastal & Regional Marine Studies

email Feedback | USGS privacy statement | Disclaimer | Accessibility

This page is http://coastal.er.usgs.gov/pontchartrain/wetland.html
Updated May 06, 2013 @ 09:24 AM (THF)