outward beneath the full crown width at 1V:1H side slopes. The cover layer 
stone size varies from 2 to 18 tons (although a particular structure may have 
used just a portion of this range), increasing in 2-ton size increments along 
successive seaward sections. The cover stone has a unique shape which resem- 
bles a rough surfaced, slightly flattened cube. The cover stone are placed in 
a single layer, except on head sections where a double layer is used on the 
side slopes. Typically, the cover layer toe is buttressed with an additional 
1 to 3 stones of equal size placed horizontally atop the bedding layer. 
9. Except for various caps used on the structures, all repairs have 
consisted of placing additional stone. The frequency of repairs was highest 
prior to World War II, although the Aransas pass and Brazos Island jetties 
have been repaired at about the same frequency to the present. The general 
trend of the repairs has been toward the use of larger stone placed on shal- 
lower side slopes. Also, the use of concrete on the jetties as a repair 
method has been discontinued. The caps have met with mixed success. The 
crown has remained reasonably intact, while the underlying stones have sub- 
sided, causing void spaces and eventual collapse of the unsupported cap. Re- 
pairs to previously capped sections have been made by adding buttressing and 
slope stone or breaking up the cap and adding stone. Several of the recent 
repair efforts have concentrated on one side of the structure using the exist- 
ing section as a buttress. Repairs at the structures' seaward ends typically 
have consisted of rebuilding the head landward of the original seaward end. 
The Port O'Connor and Port Bolivar steel structures were repaired along sea- 
ward sections by the addition of rubble-mound cross sections and have not been 
repaired since. 
10. While many of the repairs were necessitated by wave-induced damage, 
perhaps of equal importance has been the scour and undermining at the base of 
the structures caused by current- and wave-induced bottom stresses. The jett- 
ies at Sabine Pass underwent large amounts of settlement during their lengthy 
period of construction. Scour appears to have been a contributing factor of 
deterioration on the jetties at Aransas Pass, Brazos Island, Port Mansfield, 
Matagorda (during construction), Port O'Connor (prior to rehabilitation), the 
Galveston north jetty, and the Freeport south jetty. Apron stone was added to 
the Brazos Island jetties within a few years of construction. Spurs were 
placed on the Aransas Pass jetties in 1923, 1956, and 1965. The present con- 
ditions of the structures are considered good to excellent with the exception 
