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Breakwater protects harbor from hurricane surf

Published Sept. 15, 2014
The Middle Breakwater is an 18,500 foot long, detached breakwater functioning as a major structure that protects the Port of Long Beach. Hurricane Marie caused eleven major damage areas (breaches or near-breaches) and 39 other areas of significant or moderate damage. In total, repairs are needed for 1,550 feet of major damage areas, 850 feet of significantly damaged areas and 1,725 feet of moderately damaged areas.

The Middle Breakwater is an 18,500 foot long, detached breakwater functioning as a major structure that protects the Port of Long Beach. Hurricane Marie caused eleven major damage areas (breaches or near-breaches) and 39 other areas of significant or moderate damage. In total, repairs are needed for 1,550 feet of major damage areas, 850 feet of significantly damaged areas and 1,725 feet of moderately damaged areas.

For four days in late August, heavy waves generated by the winds from Hurricane Marie crushed onto the three breakwaters that protect the ports of Long Beach and Los Angeles. As a result, all three suffered damage, with the Middle Breakwater suffering the most significant damage. As soon as conditions safely allowed, the Los Angeles District dispatched coastal engineers to inspect the breakwaters by boat, air and foot. Based on their inspection, all three breakwaters are in need of emergency repairth.

For four days in late August, heavy waves generated by the winds from Hurricane Marie crushed onto the three breakwaters that protect the ports of Long Beach and Los Angeles. As a result, all three suffered damage, with the Middle Breakwater suffering the most significant damage. As soon as conditions safely allowed, the Los Angeles District dispatched coastal engineers to inspect the breakwaters by boat, air and foot. Based on their inspection, all three breakwaters are in need of emergency repairth.

LOS ANGELES – In late August, Hurricane Marie spent nearly a week churning off the coast of Mexico and Southern California. While it did not directly impact land in either Mexico or the United States, the effects of the Category 5 hurricane were significant and costly.
 
Los Angeles-Long Beach Harbor, located approximately 25 miles south of downtown Los Angeles in San Pedro Bay, is home to two high-use ports: the Port of Los Angeles and Port of Long Beach. The ports are protected by three breakwaters: San Pedro Breakwater, Middle Breakwater, and Long Beach Breakwater.
 
For four days, heavy waves generated by the winds from Hurricane Marie crushed onto the three breakwaters. As a result, all three suffered damage and are in need of emergency repair.
 
As soon as conditions safely allowed, the U.S. Army Corps of Engineers Los Angeles District dispatched coastal engineers to inspect the breakwaters by boat, air and foot. Based on their inspection, the Middle Breakwater suffered the most significant damage.

The Middle Breakwater is an 18,500 foot long, detached breakwater functioning as a major structure that protects the Port of Long Beach. Hurricane Marie caused 11 major damage areas (breaches or near-breaches) and 39 other areas of significant or moderate damage. In total, repairs are needed for 1,550 feet of major damage areas, 850 feet of significantly damaged areas and 1,725 feet of moderately damaged areas, said Jim Fields, the Corps’ project manager for the ports of Long Beach and Los Angeles.  

"The Ports of Long Beach and Los Angeles are the nation's busiest -- and key economic engines," said Port of Long Beach chief executive Jon Slangerup. "The major damages here from Hurricane Marie and the disruption to our vessel operations just underscore the critical part that the federal breakwater plays in providing us with a safe harbor."
 
In determining the impact of the damage, coastal engineers considered two factors: the functionality of the breakwaters and their structural integrity.

Fields said the breakwater in its current condition remains functional, but compromised, and with any significant wave or storm event in the area, its functionality will decrease as wave height increases.
 
The probability of strong wave conditions is expected to increase in the next few months, increasing the risk of storm damages to harbor infrastructure and possibly impacting port operations. The hurricane season extends until the end of November and will be followed directly by the winter storm season. Therefore, according to Fields, repairs to breached areas should be made immediately.

“As with all these types of structures,” Fields said, “once they start to come apart they are very susceptible to greater damage following any additional significant wave event. And any breaches of the breakwater will allow greater transmission of wave energy into the inner portions of the harbor.”

Based on the District’s assessment, the 11 major damaged areas on the Middle Breakwater need to be fixed immediately. Eight significant areas are classified in the same category as the breaches, due to the fact they only have one layer of rock without any interlocking. These areas potentially would be the next to fail, according to Fields.
 
Since the breakwater is not accessible by land, repairing it will involve water-based equipment, consisting of a crane and rock barges. The proposed repair will entail stone replacement with new rocks and shifting existing rocks to achieve a proper interlocking. The goal is to repair these sections back to their authorized dimensions, with an elevation of 14 feet above Mean Lower Low Water. The contractor will acquire rocks for the breakwater from a quarry yet to be determined according to contract specification.
 
Since water depths in the area are adequate, no excavation is expected for the repairs. Engineers do expect that temporary, minor impacts to the water quality would occur from an increase in turbidity during the construction period from resetting the existing stones and from placing new quarry stones on the breakwater. Disturbance to marine mammals and seabirds caused by the breakwater repairs is expected to be short-term, as animals are expected to acclimate to the non-threatening construction noise.

“We will conduct the proper NEPA process and address all the related environmental concerns,” Fields said.

The District is looking into funding options to execute this work.