Seafloor studies of Mamala Bay, Honolulu, Hawaii




No comprehensive study of the effects of disposal of dredge spoils has been conducted to determine if the environment has suffered. The U.S. Army Corps of Engineers (USACE) has regularly dredged the shipping channels of Honolulu Harbor and Pearl Harbor for commercial and military purposes. The 5-year frequency for new dredging activity has led to the formation of extensive offshore wide deposits of relatively coarse sediments being created in a sedimentary environment that naturally collects much finer-grained materials. At the same time, the rapid growth of Honolulu and its suburban region over the past 3 decades has added nutrient-enriched sewage outfall to the artificially-heavy sediment load. The combined effects of dredge-spoil disposal and contaminant loads are not well-documented, and are poorly understood. The U.S. Geological Survey (USGS) began a comprehensive study to characterize the seafloor of Mamala Bay.

In 1993, the USGS initiated a program sponsored by the USACE and the U.S. Environmental Protection Agency that produced a detailed map of the seafloor, especially of the distribution of dredge spoils, and a preliminary analysis of the environmental effects of dredge-spoils disposal and the chemical effects of the introduction of nutrient-rich outfall. Part of the work would involve sediment sampling, biological testing, and evaluation. Of particular interest is tissue sampling and analysis of endemic shrimp to determine the rates of absorption of toxic elements, such as heavy metals, that are easily brought into the food chain.

Study Area

Publication type Report
Publication Subtype USGS Unnumbered Series
Title Seafloor studies of Mamala Bay, Honolulu, Hawaii
DOI 10.3133/70182019
Language English
Publisher U.S. Geological Survey
Publisher location Reston, VA
Contributing office(s) Coastal and Marine Geology Program
Description HTML Document
Public Comments Published between 2000 and 2004
Country United States
State Hawaii
City Honolulu
Other Geospatial Mamala Bay
Online Only (Y/N) Y
Google Analytic Metrics Metrics page
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