Del Mar approves next phase of work to safeguard railroad bluff
Construction starts next year on more seawalls, drainage ditches & soldier piles to safeguard tracks until new route with tunnel is built
The Del Mar City Council this week unanimously approved an encroachment permit for the next phase of bluff stabilization work intended to safeguard the seaside railroad tracks until they can be moved to a new route.
The proposed construction is the fifth phase in a series of seawalls, drainage ditches and soldier piles installed by the San Diego Association of Governments to slow the erosion that eats away the coastal cliffs beneath the tracks in Del Mar at an average rate of four to six inches a year.
“This is an important and necessary project,” said Del Mar Mayor Dwight Worden. “It’s a key step in getting the rails off of the bluff eventually.”
Work on the safety measures is expected to begin in June 2023 and continue through June 2026, typically between 7 a.m. and 7 p.m., but occasionally at night and on weekends to avoid train traffic. The 1.6-mile stretch of tracks goes between the city’s Seagrove Park and the overhead bridge at Torrey Pines State Beach.
Three key features are included in the project — seawalls, drainage structures and soldier piles, said SANDAG Senior Engineer Allie DeVaux, in a presentation Monday, Nov. 14, to the Del Mar council.
The 1,000 feet of seawalls now at the base of the bluffs will be extended by 2,000 feet, she said. The seawalls consist of heavy wood boards, or lagging, held in place by steel columns or piles. They are designed to be removed after the railroad tracks are relocated so the beach can return to normal. The walls reach 15 feet above sea level, but only about half of that extends above the sand depending on the time of year and the condition of the beach.
Additional drainage improvements will be added to better handle storm and groundwater runoff, DeVaux said. The existing drainage system can be overwhelmed during storms, as happened in 2019 when emergency repairs were required.
And third, additional soldier piles will be installed. Hundreds of the concrete-and-steel columns have already been placed deep in the ground on the upper bluffs, and more are needed to support the track bed in preparation for earthquakes and bluff erosion. Also, the new piles will be connected by surface-level beams for further stabilization, and beams and tie-backs will be added to some of the piles already installed.
Three elements also are included in the project to improve public access to the area, DeVaux said. These are a pedestrian railroad crossing, an access trail from the top of the bluff to the beach, and a blufftop trail between Seagrove Park and Fourth Street.
Construction of the public access features will start in about three years after the stabilization work is finished, DeVaux said.
The encroachment permit approved Monday, Nov. 14, allows workers to use the city’s public right-of-way and property to access construction sites. Some of the storm drains will be installed on city property.
The stabilization work was planned more than 20 years ago as a six-phase program to protect the tracks on the bluffs until 2050. From the beginning, the long-term goal has been to eventually move to a new inland route.
Accelerating erosion and recent bluff collapses have brought a new urgency, along with public and political support, to the effort. Studies show the fastest, safest and least environmentally destructive route is a tunnel beneath Del Mar.
SANDAG developed five possible routes for the tunnel in 2017. Since then the routes have been narrowed to two based on train speeds, environmental effects, and construction costs.
The new route also would accommodate the construction of a second set of tracks, which would allow trains to pass each other and increase the speed and efficiency of service. So far, SANDAG has double-tracked about 75 percent of the 60 miles of the coastal rail corridor in San Diego County.
This year, SANDAG received $300 million in state funding for the design, engineering and environmental work needed over the next five years to prepare for construction. The project is on track to begin in 2028 and to open for service in 2035, said SANDAG Senior Transportation Engineer Sharon Humphreys.
Completion of the preliminary work also makes the Del Mar realignment more likely to qualify for the federal and state grants needed to pay for construction, which could cost more than $4 billion.
The 140-year-old railroad in Del Mar is part of the only viable route for passenger and freight trains between San Diego and the rest of the United States.
The 350-mile line between San Diego, Los Angeles and San Luis Obispo, known as the LOSSAN corridor, is one of the nation’s busiest passenger rail routes and an important freight connection to the Port of San Diego.
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