Deeper dredging proposed for Oceanside harbor

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Dredging equipment in 2018 stationed on the north side of the mouth of the Oceanside Harbor, alongside the Del Mar jetty. (Charlie Neuman)

Posted February 12, 2020

Project could produce more sand on city beaches

OCEANSIDE — This year’s spring cleaning of the Oceanside harbor’s entrance could be deeper than in recent years, an effort to make navigation safer and produce more sand for the city’s beaches.

The annual dredging removes sand that builds up in the harbor entrance during winter storms and high tides, and pipes the sediment onto the beaches to the south. In past years, the harbor channel was dredged to a maximum depth of 25 feet, but this year the goal is 30 feet.

“This is the first year they will go that deep,” Oceanside Public Works Director Kiel Koger said in an email. “The advantages are it will keep the main navigation channel open and take longer to fill in with sand, and we should get more sand placed on the beach with the added volume.”

Manson Construction, the contractor, recently started a dredging project in Ventura and when finished there it will move to Oceanside, probably in late March, Koger said. The goal is to finish the Oceanside job by Memorial Day weekend, which is traditionally the start of the summer tourist season.

A spokeswoman for the U.S. Army Corps of Engineers in Los Angeles, which oversees the dredging project, said Wednesday that the agency is still awaiting authorization to dredge to the deeper level and anticipates a decision by early April.

“When the Corps did its last round of testing, the material was tested all the way to the 30 (foot) depth in anticipation of receiving the proper authorization to dig to this deep,” said Dena O’Dell, deputy chief of public affairs, in an email.

“The 30-foot depth would only be dredged at the center of the channel, so the rock structures that protect the harbor won’t be impacted,” she said.

The work requires permits and permission from state and local agencies such as the California Coastal Commission and the Regional Water Quality Control Board. Sometimes, problems obtaining those permits can delay the project, which happened in 2018.

Waves and currents constantly push sand into the man-made harbor, built in the 1960s, but it happens faster in winter.

“During the winter, south swells deposit sand back into the channel and make it much shallower,” said Ted Schiafone, the city’s harbor division manager.

“As a result, waves have the potential to break in the entrance channel, making navigation for some vessels very dangerous,” he said. “In the past, we have had multiple vessels capsize in the harbor.”

Dredging the harbor entrance to the 25-foot depth in past years has yielded about 225,000 to 250,000 cubic yards of sand, which usually is placed on a few blocks south of the harbor but north of the municipal pier. This year, the deeper scouring could produce up to 400,000 cubic yards, a portion of which could go to the narrow, eroded beaches south of the pier.

The total amount of sand removed each year depends on several factors, including the weather and ocean swells during the work and the condition of the contractor’s equipment. Another potential problem is the mating cycle of the grunion, a small fish that must be avoided when it spawns on the beach at certain times of the year.

The U.S. Army Corps of Engineers is responsible for keeping coastal waterways navigable. The Corps signed an ongoing contract with Manson in 2017 to do the Oceanside maintenance job for about $5 million a year.

Some years, Oceanside pays extra to extend the Manson contract and put additional sand on the beach. This year, the city has offered to pay up to $600,000 for more sand, if it’s available.

The Oceanside harbor entrance is shared with what’s called the Camp Pendleton “boat basin,” a rectangular-shaped harbor used for military training and recreational purposes at the southwestern corner of the Marine Corps base.

Army Corps officials announced Wednesday they have awarded a $2.9 million contract to Curtin Maritime Corp. of Long Beach to dredge the channel at the southern end of San Diego Bay for the first time since 1976.

The sediment dredged from that project, covering nearly 96 acres, will be dumped in an ocean disposal site six miles southwest of the San Diego Bay entrance. Completion is expected by March 31.