Table 13 



Fernandina Harbor Jetties 



Fernandina Harbor, Florida, SAJ 



Date(s) Construction and Rehabilitation History 



1880- As authorized in 1880, the north jetty was to be 18,000 ft long and 

 1913 the south jetty a little over 12,000 ft long. The crests were to be 

 at the level of mean low tide, except the outer 3,300 ft of each, 

 which was to be at midtide level. The River and Harbor Act of 1892 

 provided for a 19-ft-deep channel and fixed 3,900 ft as the width 

 between the outer ends of the jetties. The north jetty was first to 

 be raised to a height sufficient to retard effectively the sand 

 movement southward. The south jetty was then to be raised and ex- 

 tended as necessary to secure the desired depth over the bar. The 

 River and Harbor Act of 1896 provided for raising the jetties to mhw 

 (+6 ft mlw) . 



Jetty construction methods were in many respects similar to those 

 used on other regional projects built during this time. The jetties 

 were built using alternate layers of stone and log mattresses, as 

 many as eight courses being used in some sections. Built initially 

 at and below mean low water, the jetties were subsequently extended 

 and raised (using rubble stone) over a period of several years. 

 During construction, the south jetty had sections removed to allow 

 the then existing channel (and shipping) to pass through it. The 

 1903 Annual Report to the Chief of Engineers stated that, except for 

 a few low places where settlement had occurred or stones had been 

 displaced by wave action, the north jetty was completed to the 

 elevation of high water from the shore to 190+00 (approximately its 

 present outer end) . It stated that the inner slope between 20+00 

 and 106+77 had been reinforced with riprap, as the difference in 

 head between the water inside and outside was so great that flow 

 through the jetty caused dangerous scour at the base on each side. 

 In 1903 the south jetty was completed to the elevation of high water 

 for 7,500 ft of its length, to -5 ft mlw for the next 3,500 ft, atid 

 a 60-ft-wide apron was placed against the inner slope from sta 74+20 

 to 89+37. The jetties were completed to mhw in 1905, the north and 

 south being 19,150 and 11,200 ft long, respectively (Figure 21). 

 The seaward ends converged to a distance of 3,900 ft and were 

 parallel over the final 1,500 ft of their lengths. After 1905 

 considerable repair work was done on the jetties to raise subsided 

 sections and replace stone carried away by storms. These repairs 

 were made from time to time up to 1913. 



1926- Work under contract to repair both jetties began in February and was 

 1927 completed 1 year later. This repair resulted in raising the north 



jetty to +7 ft mlw and the south jetty to +6 ft mlw. In each case, 



the crest width was 8 ft. 



(Continued) 

 39 



