Accession Number:

ADA172504

Title:

Migration of Isles Dernieres: Past and Future.

Descriptive Note:

Final rept.,

Corporate Author:

COASTAL ENGINEERING RESEARCH CENTER VICKSBURG MS

Personal Author(s):

• Britsch,Louis D.

Report Date:

1986-08-01

Pagination or Media Count:

44.0

Abstract:

Isles Dernieres comprise a barrier island complex located in the southwestern portion of the Mississippi River deltaic plain. The islands formed from reworking of the Early Lafourche deltaic headland deposited from approximately 1,000-300 years B.P. Isles Dernieres have been experiencing a high rate of land loss due to wave attack and rapid subsidence, recently prompting local officials to consider ways of preventing any further deterioration of the coastline. The migration of Isles Dernieres is controlled mainly by overwash, tidal currents, longshore drift, and subsidence. Using historic topographic maps, bathymetric surveys, and aerial photographs, quantitative values were placed on each of the factors influencing migration. By comparing the data pertaining to each of the four factors controlling migration, the trend of these factors through time was determined. The analysis indicates that Isles Dernieres are making the transition from a wave-dominated regime to one of mixed energy, probably resulting in future change in the observed pattern of migration and decreased rates of migration.

Descriptors:

• *ISLANDS
• HIGH RATE
• ATTACK
• ENERGY
• RATES
• BATHYMETRY
• TIDAL CURRENTS
• DRIFT
• SURVEYS
• PATTERNS
• MIGRATION
• MIXING
• LOSSES
• AERIAL PHOTOGRAPHS
• MISSISSIPPI RIVER
• DETERIORATION
• WAVES
• LAND AREAS
• SHORES
• DELTAS
• MEXICO GULF

Subject Categories:

• Physical and Dynamic Oceanography

Distribution Statement:

APPROVED FOR PUBLIC RELEASE