REPORT DOCUMENTATION PAGE 



Form Approved 

 OMB No. 0704-01 88 



Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing Instructions, searching existing data sources 

 gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this 

 collection of information, including suggestions for reducing this burden, to Washington Headquarters Services. Directorate for Information Operations and Reports. 1215 Jefferson 

 Davis Highway. Suite 1204, Arlington, VA 22202-4302, and to the Office of Management and Budget. Paperwork Reduction Project (0704-0 188). Washington, OC 20S03. 



1. AGENCY USE ONLY (Leave blank) 



2. REPORT DATE 

 August 1997 



3. REPORT TYPE AND DATES COVERED 



Final report 



4. TITLE AND SUBTITLE 



Periodic Inspection of Humboldt Bay Jetties, Eureka, California 



6. AUTHOR(S) 



Robert R. Bottin, Jr., William S. Appleton 



5. FUNDING NUMBERS 



7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) 



U.S. Army Engineer Waterways Experiment Station 

 3909 Halls Ferry Road, Vicksburg, MS 39180-6199 

 U.S. Army Engineer District, San Francisco 

 San Francisco, CA 94105-1905 



8. PERFORMING ORGANIZATION 

 REPORT NUMBER 



Technical Report CHL-97-17 



9. SPONSORING /MONITORING AGENCY NAME(S) AND ADDRESS(ES) 



U.S. Army Corps of Engineers, Washington, DC 20314-1000 



10. SPONSORING /MONITORING 

 AGENCY REPORT NUMBER 



11. SUPPLEMENTARY NOTES 



Available from National Technical Information Service, 5285 Port Royal Road, Springfield, VA 22161. 



12a. DISTRIBUTION /AVAILABILITY STATEMENT 



Approved for public release; distribution is unlimited 



12b. DISTRIBUTION CODE 



13. ABSTRACT (Maximum 200 words) 



The Humboldt Bay jetties at Eureka, CA have experienced a long history of damage and subsequent repairs since original 

 construction was completed in 1 899. Since dobs rehabilitation of the heads of the jetties in 1 97 1 , damages have been primarily along 

 the trunk (stone) reaches of the jetties. No extensive work has been required along the dobs fields since their construction. Prior 

 to the study documented in this report, no sound, quantifiable data relative to the movement or positions of the dobs concrete armor 

 units had been obtained for the jetties. 



Data were obtained under the Monitoring Completed Navigation Projects Program from limited ground-based surveys, aerial 

 photography, and photogrammetric analysis to establish very precise base level conditions for the seaward dobs-covered portions of 

 the Humboldt Bay jetties. A method using high-resolution, aerial stereo photographs, a stereopbtter, and Intergraph-based software 

 has been developed to analyze theentire above-water concrete armorunitfields and quantify armor positions and subsequent movement 

 A detailed broken armor unit survey conducted during the current effort has resulted in a well-documented data set that can be compared 

 to subsequent survey data. 



This study has denned base conditions and has developed a methodology that can be used to compare subsequent years of high- 

 resolution data for the Humboldt Bay jetties and use these data to assess the long-term response of the structure to its environment. 

 These efforts will allow engineers to decide whether or not closer surveillance and/or repair of the structures might be required to 

 reduce their chances of failing catastrophically. 



14. SUBJECT TERMS 



Concrete armor units 

 Dolosse 

 Humboldt Bay, CA 



Jetties 



Periodic Inspections 



Photogrammetry 



Remote Sensing 



15. NUMBER OF PAGES 



48 



16. PRICE CODE 



17. SECURITY CLASSIFICATION 

 OF REPORT 



UNCLASSIFIED 



18. SECURITY CLASSIFICATION 

 OF THIS PAGE 



UNCLASSIFIED 



SECURITY CLASSIFICATION 

 OF ABSTRACT 



20. LIMITATION OF ABSTRACT 



NSN 7540-01-280-5500 



Standard Form 298 (Rev. 2-89) 



Prescribed by ANSI Std Z39-18 

 298-102 



