American Society of Civil Engineers


Humboldt Beach and Dune Monitoring


by John Winkelman, (USACE San Francisco District, 333 Market Street, San Francisco, CA 94105, United States), Dan Schaaf, (USACE San Francisco District, 333 Market Street, San Francisco, CA 94105, United States), and Tom Kendall, (USACE San Francisco District, 333 Market Street, San Francisco, CA 94105, United States)

pp. 176-190

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Document type: Conference Proceeding Paper
Part of: Sand Rights ’99: Bringing Back the Beaches
Abstract: Since 1881, the U.S. Army Corps of Engineers has maintained the entrance channel to Humboldt Bay on the Northern California Coast. This is accomplished through the annual dredging of approximately 382,000 m3 (500,000 yds3) of beach quality sand from the ebb shoal and jettied entrance channel. Since 1990, this material has been disposed of in deep water at the Humboldt Open Ocean Disposal Site (HOODS). To monitor any potential impacts from the removal of this large quantity of sand from the littoral system, a beach and dune monitoring program was instituted in 1991 using aerial photography and ground surveys. Any adverse findings from this monitoring would be used as a basis for revisiting the use of HOODS. After two surveying episodes, the aerial photographic analysis and ground surveys were found to be producing conflicting results. Therefore, the survey methodology was changed in 1998 to digital ortho photography. This method greatly increased the accuracy of the monitoring program and was retroactively applied to all monitoring surveys. Monitoring results to date fall within historical trend lines. However, the new methodology has yet to be applied to the historic data.


ASCE Subject Headings:
Aerial photography
Bays
Channels
Digital techniques
Dredging
Dunes
Monitoring

Author Keywords:
Beaches
Aerial photography - Coastal zones - Dredging - Jetties - Ocean dumping - Sand - Shore protection - Surveys
Digital orthophotography - Dune monitoring - Humboldt beach - Ocean disposal site