(3) Currents. Largely northwest from July through February, and southeast from 

 March through June (U.S. Navy Hydrographic Office, 1947). 



(4) Winds. Prevailing west-southwest winds from April through September; west 

 winds from October through March, with maximum recorded velocity of 54 knots during 

 this period (Department of Commerce, 1968). 



(5) Storm Surge and Tides (U.S. War Department, U.S. Engineer Office, 1939). 



MHHW, 5.4 feet above MLLW 

 Mean tide level, 2.8 feet above MLLW 

 Extreme low, 2.5 feet below MLLW 

 Mean tide range, 4.0 feet 

 Extreme tidal range, 10.0 feet 



(6) Littoral Transport. Negligible. 



(7) Water Depth at Structure. Built generally along a 50-foot depth contour with 

 actual depths varying from 46 to 56 feet at MLLW. 



(8) Foundation Conditions. Generally hard shaly clay, 

 e. Structural Features (Figs. 43 and 44). 



(1) Dimensions of Basic Structures. Length, 12,500 feet at 55° bearing; middle 

 breakwater, 6,000 feet at 90° bearing; total, 18,500 feet; Long Beach breakwater, 13,350 

 feet at 90° bearing. 



Side slopes: 



Class A capstone: 1.5 to 1 (harbor side), 2.0 to 1 (ocean side) 

 Class B capstone: 1.25 to 1 (harbor side), 2.0 to 1 (ocean side) 

 Crest elevation and width: 14 feet above MLLW, 16 feet wide 



(2) Unusual Structural Features. Designers, taking advantage of exceptional type of 

 stiff shaly clay available from channel and harbor dredging in the area, substituted this 

 material for rock in the lower levels on a yard-for-yard basis, to keep construction costs to 

 an absolute minimum. The clay is not plastic, but a very sandy incipient shale of high 

 coUoidal content, and is not subject to flow except under great pressure. Stones of 

 Classes A, B, and later C were specified according to maximum and minimum size and 

 gradation (Marcy, 1935). The B stones were dumped by barge while the A-stone caprocks 

 were carefully placed by derrick to secure better interlocking, reduce voids and provide 

 smoothness. Dropping of stones on earth layers also aided compaction and settlement. 



/. Design Data. 



(1) Design Conditions: 



Depth at structure, 46 to 56 feet at MLLW 



Extreme tide range, 10 feet above MLLW 



Maximum depth, 66 feet 



Design wave, 27 feet (from September 1939 storm conditions) 



79 



