ROBERTS, HARRY H., and W. WINANS, Coastal Studies Institute, LSU, Baton Rouge, Louisiana 70803; and C. A. WILSON and J. SUPAN, Coastal Fisheries Institute, LSU, Baton Rouge, LA 70803
Abstract: New Technology for Characterizing Louisiana's Shallow Coastal Water Bottoms and Predicting Future Changes
Louisiana's rapidly changing land-water interfaces have caused both Federal and State support to be focused on various strategies related to coastal restoration. Most promising of these strategies is river diversions which introduce freshwater and sediment to river-flanking environments (lakes, bays, and associated marshlands). Two river diversions planned by Louisiana Department of Wildlife and Fisheries and U.S. Army Corps of Engineers, Caenarvon and Davis Pond, are designed to nourish marshes with water and sediment as well as to help establish ideal isohalines over historic oyster grounds. Already, pending litigation against the State related to environmental changes associated with the Caenarvon diversion amounts to tens of millions of dollars. For the first time digital high resolution acoustic instrumentation linked to state-of-the-art data acquisition and processing software is available for building a baseline of information that can be used for evaluating future changes of shallow water bottoms. Application of digital side-scan sonar (100 and 500 kHz) and a broad-spectrum subbottom profiler (4-24 kHz) for rapidly acquiring both surficial. and shallow subsurface data (average water depths 0.7 to ~ 3.0 in) has now been accomplished. These data sets "calibrated" with coring, surface sampling, and other "ground truthing" techniques have enormous potential for understanding (a) distributions of bottom sediment types, (b) locations of oyster reefs and distributions of scattered oyster clumps and shells, (c) fisheries habitats, (d) areas of active sedimentation and erosion, and (e) shallow subsurface configurations that influence surface conditions. This approach of linking high resolution acoustic data with various direct sampling techniques has been verified in pilot studies. We have initiated a program for establishing a baseline data set for evaluating future change in all of Louisiana's coastal water bottoms.
AAPG Search and Discovery Article #90924©1999 GCAGS Annual Meeting Lafayette, Louisiana