Biologists concerned about sand, mud buildup

By: BARBARA HENRY - Staff Writer
Study to focus on condition of Batiquitos Lagoon | Thursday, February 28, 2008 10:23 PM PST ∞

CARLSBAD ---- Day by day, a bit more muck and sand slides into Batiquitos Lagoon.

To the east, San Marcos Creek pushes mud in. To the west, ocean waves shove piles of sand toward the lagoon's mouth. And, from all sides, murky rainwater pours in during storms.

Biologists who study the south Carlsbad lagoon and nature lovers who run the lagoon protection group say they're worried about how quickly the sand and muck pile is accumulating, and whether that means a massive dredging operation will soon be required.

Earlier this month, the Batiquitos Lagoon Foundation won a nearly $75,000 grant from Carlsbad to study the topic.

"Right now, we don't really know how bad the situation is," said Keith Merkel, one of the owners of a consulting company that has been doing bird and fish research at the lagoon.

However, anecdotal evidence collected by wildlife researchers in boats and foundation volunteers on land suggests that some spots don't contain as much water as they did a decade ago, Merkel said.

"We run aground in places (now that) we never used to," he said.

His company was hired to monitor wildlife conditions after a $57 million dredging effort reopened the lagoon's mouth in December 1996.

Backers of that project knew that it would eventually need to be repeated, but they forecast that the work could wait 30 years or more, said Tim Dillingham, the state Department of Fish & Game employee who manages the lagoon area.

"I was really hoping I would be retired before this is necessary," he joked.

A smelly spot

The nearly 600-acre Batiquitos Lagoon is considered one of the jewels of Carlsbad ---- joggers regularly run along the nature trail on the lagoon's north side, many rare birds nest its marshlands and dozens of fish swim in its waters. Its ownership is shared by Fish and Game and the State Lands Commission.

It wasn't always such a pleasant place.

Twenty years ago, it was the smelliest of Carlsbad's three lagoons, though its neighbor to the north ---- Agua Hedionda Lagoon --- is the one with the Spanish name that translates as "stinky," Merkel said.

For decades, a sandbar blocked Batiquitos Lagoon's entranceway to the ocean, so the water couldn't be flushed regularly by the tide. Instead, there was an abundance of water during the wet winter months, but little during the summer and fall. The stinky conditions were worst in hot, dry periods when water dried up, algae decayed and fish died, Merkel recalled.

Some bird species loved it because they could easily capture fish as the water levels dropped, but the smell didn't make nearby homeowners happy, said Dillingham, the state land manager.

The situation changed thanks to the Port of Los Angeles.

Moving the muck

In exchange for being allowed to expand a massive cargo ship off-loading area, the port was required to do a large wetland improvement project, and Batiquitos Lagoon was picked for the funding, Dillingham said.

The $57 million project included dredging 1.7 million cubic yards of sand out of the front end of the lagoon ---- virtually enough for "an entire beach" ---- and dumping it across nearby beaches, Dillingham said.

Removing the sand from the lagoon created a huge underwater hole between the railroad tracks and Interstate 5, he said. Into that hole, the dredging equipment dumped tons of muck from the eastern end of the lagoon, then covered it with sand, Dillingham said.

It was a simple solution ---- disposing of the muck outside of the lagoon would have been very costly, Dillingham said. Unlike sand, mud isn't a sought-after commodity. And, that's going to be a problem when the state decides to move forward with a second, large-scale dredging effort, he added.

The easy fix has already been done at the lagoon. The second time around, the muck that's dredged up is going to have to be extracted and taken elsewhere, Dillingham said, adding that he's afraid to think about how much the cost might be.

"Given the condition of the (state's finances) right now, we're probably not going to get funding," he said.

The next step

There is some money already set aside for lagoon work. The port had to contribute $5 million for a lagoon endowment to pay for work over the project's 30-year estimated life span. It also set aside $3 million for the next major dredging project, Dillingham said.

Interest from the $5 million endowment is funding Merkel's wildlife research work and it's paying for the minor dredging efforts that occur every three years or so at the lagoon, Dillingham said.

The next round of dredging is expected to take place in 2009.

Meanwhile, the wildlife researchers at Merkel & Associates are completing a 10-year status report on the lagoon's wildlife. That document should be out by the end of March, Merkel said.

Now that the lagoon foundation has gotten the grant from Carlsbad, the next step will be to conduct depth measurements in the lagoon and to research tidal conditions, he said.

"The tides in the lagoon are so lagging (that they) no longer are matching the ocean," Merkel said, adding that's another indicator that the lagoon is filling in with sediment.

Carlsbad is looking forward to hearing what the research produces.

"We've got a tremendous interest in making sure (the lagoon is) in great shape ----- it's the entryway to the city," said Scott Donnell, the senior city planner who processed the grant application. "It's an attraction that draws people and we want to make sure it remains such."

Contact staff writer Barbara Henry at (760) 901-4072 or bhenry@nctimes.com.

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