In 1993, the USGS initiated a program sponsored by the USACE and the U.S. Geological Survey (USGS) began a comprehensive study to characterize the seafloor of Mamala Bay. The combined effects of dredge-spoil disposal and contaminant loads are not well-documented, and are poorly understood. 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 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. Army Corps of Engineers (USACE) has regularly dredged the shipping channels of Honolulu Harbor and Pearl Harbor for commercial and military purposes. No comprehensive study of the effects of disposal of dredge spoils has been conducted to determine if the environment has suffered. Location map of the Hawaiian Islands showing designated dredged spoil disposal sites for Hawaii's harbors. Half a century of dredge spoils disposal has had an unknown effect on the Mamala Bay ecosystem.

No satisfactorybathymetric map of the seafloor had existed, and little information hasbeen compiled about the effects of these activities to determinewhether modifications to the operation and management of the designateddump sites and sewage outfall locations were necessary.'

'Disposal of dredge spoils in the near offshore area, coupled with therapid growth of Honolulu and other nearby municipalities, has placedincreased stress on the environment of Mamala Bay.

Seafloor Studies of Mamala Bay, Honolulu, Hawaii - USGS Fact SheetĬoastal and Marine Geology Program > Seafloor Studies of Mamala Bay, Honolulu, Hawaii Seafloor Studies of Mamala Bay, Honolulu, Hawaii USGS Fact Sheet

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