DESIGN AND CONSTRUCTION OF HUMBOLDT JETTIES, 1880 to 1975

Abstract

In the Chief of Engineers annual report of 1877, it was concluded that "The only way...in which a safe entrance could be obtained into this harbor would be by the construction of two parallel jetties, of very heavy stone, about 500 yards apart, from the north and south spits at the entrance." In 1882, a special Board of Engineers concluded that the "occupation of the south breaker spit by a structure...carried to low water and running from the south head (spit) in a north-westerly direction..." be built. Construction of the south jetty began in 1889 and of the north jetty, subsequently authorized, in 1891. Due to the severe wave action, a number of rubble-mound construction techniques including stone, concrete cubes, tetrahedrons, and finally dolos armor units have been used. A description will be given of the construction and associated results. Experience with the reinforced and unreinforced concrete dolosse units will also be discussed.