Lake Pontchartrain Basin:  Bottom Sediments and Related Environmental Resources

USGS Professional Paper 1634


By  S. Jeffress Williams

Lake Pontchartrain, as the largest estuary in southern Louisiana, is an important recreational, commercial, and environmental resource for New Orleans, southeastern Louisiana, and the Nation. This publication is one of the products resulting from a 5-year cooperative program started in 1995 by the U.S. Geological Survey ( The program is focused on the geological framework and sedimentary processes of the Lake Pontchartrain Basin. Detailed documentation of selected aspects of the cooperative program are provided here.

This product presents information designed for a wide circle of users, including scientists, managers, planners, students, and the public. The formatting of this CD for web browsers allows users to navigate its extensive detail like a standard Internet website. As seen in the Table of Contents, the information is organized into two principal parts.

One part provides new scientific research results and documentation. This part includes the first release of a comprehensive database and report on the chemistry and environmental status of bottom sediments from Lake Pontchartrain and surrounding waterways. The database and interpretive maps provide new detail on the distribution of toxic metals and their probable origins. The sediment summary also reviews highlights from studies performed during the 1997 opening of the Bonnet Carré Spillway. Results of chemical analyses of time-dated cores are reported, charting contaminant concentrations off New Orleans since the early 1930's. This part of the document also presents an overview of the history of the region and explains methods of studying lake-bed sediments including remote sensing surveys, sampling techniques, sediment transport modeling, and satellite imagery.

The second part provides a variety of supporting resources including interactive tools and regional research. The sediment data are provided in Geographic Information Systems (GIS) formats for display and analysis. Two mapping systems are contained on this CD enabling users with or without specialized training to plot these data and overlay them with other Federal and State data sets. An instructional video on vibracore sampling in Lake Pontchartrain shows how USGS scientists recover long and continuous sediment cores using a 50-foot research vessel. Valuable regional research is summarized here in abstracts from four meetings of the Basics of the Basin Symposium and presented in the same web-compatible format as the rest of the CD.

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