Construction crew turns Del Mar Fairgrounds parking lot into tidal wetland

A construction crew is digging up thousands of cubic yards of dirt from a former parking lot next to the Del Mar Fairgrounds as part of an ambitious plan to restore the property to a tidal wetland, as it existed long before humans began developing the North County coast.

The work, which began in September, represents the second phase of a project to restore about 15 acres, used for decades as a dirt parking lot for the San Diego County Fair and other events, into natural habitat for birds, fish, mammals and plants.

In 2013, the 22nd District Agricultural Association, which runs the state-owned fairgrounds, agreed to restore its south overflow lot in exchange for permission from the California Coastal Commission to use another dirt lot, to the east of the fairgrounds, for parking and events such as annual pumpkin and Christmas tree sales.

Construction workers using heavy equipment are digging out channels and shaping islands and fingers of land in order to allow the property to flood twice each day with the high tide, said Mark Laska, president of Great Ecology, an environmental consultant to the contractor, Marathon Construction Corp.

“By excavating it, we’ll make it a tidal wetland,” said Laska. “That’s a dramatic change.”

By the time the project is completed in late March, workers will have excavated some 45,000 cubic yards of dirt. About 10,000 cubic feet will remain on the property to be used for land formations, while about 35,000 cubic feet will be hauled away to the landfill, said Joe Ellis, the construction superintendent.

The 22nd DAA is spending $2.25 million on the second phase of restoration project, said Dustin Fuller, supervising environmental planner with the agency. An earlier, smaller restoration project adjacent to the current project site cost $1.5 million and was completed in early 2015. When the second phase is completed, which consists of about 12 acres, a total of 15 acres of wetland will have been restored.

The work is essentially reversing actions carried out decades ago, when fill dirt was brought in to prevent flooding of the property. It has been used as a parking lot since the late 1960s or early 1970s, Fuller said.

The transformation of the parking lot into a tidal wetland will occur in three steps, said Laska. First, the flat parking lot is being excavated to remove the fill. Second, the land will be contoured to allow for tidal inundation and to create varied elevations. Finally, some 35,000 plants will be brought in.

Some will be salt-tolerant for the low lying areas, while others, such as sage and buckwheat, will be planted in upland areas, said Michelle Landis, project manager with Great Ecology.

The restoration won’t include stocking the project area with fish, birds or other animals, said Laska.

“Our attitude is, if we build it, they will come,” he said, noting that numerous studies of such restorations have shown that once tidal inundation is restored and plant life is introduced, fish and wildlife will follow on their own.

“The philosophy is we make the habitat and the birds, insects, mammals and fish will find it,” he said. He estimated that once the restoration is complete, the area may be home to as many as 125 to 150 bird species.

The restored wetland will also offer benefits for human visitors, said Fuller. Interpretive signs and a bench are in the works, and the project includes construction of a section of the Coast to Crest Trail, which will eventually link Vulcan Mountain near Julian to the beach at Del Mar. A bus ramp and turnaround will be available as a parking area for trail users when events such as the fair and horse races are not going on, Fuller said.

Once the restoration is completed, said Laska, it should closely resemble nearby natural areas in terms of its plant and animal species.

“We expect we’ll end up with a fantastic natural system when this is fully constructed,” he said.