Ecological ‘Heart Attack’ Feared if IB Sand Closes the Tijuana River

Experts at the Tijuana River National Estuarine Research Reserve are concerned sand from a recent replenishment project could impact flow of the Tijuana River and threaten life supported by Southern California's largest coastal wetland.

Ponding water that seeps below Seacoast Drive homes and condos after a sand replenishment project has roused residents and beachgoers.

But environmental workers are worried, too—that the sand could move south and block the mouth of the Tijuana River.

If the sand stopped flow of the river, said the manager of the Tijuana Slough National Wildlife Refuge, it could threaten endangered species and other wildlife in the Tijuana River Valley.

“It’s like your circulatory system,” said Brian Collins, the refuge manager. “You don’t want it blocked. It causes a heart attack. Or like asthma. You want to be able to breathe, and my analogy is you want the water to be able to go in and out."

The potential closure is especially worrisome as threatened and endangered bird species like the Light-Footed Clapper Rail are expected to begin their breeding and nesting seasons this month.

“I’ve seen raptors and other birds already flying around near the pier with nesting material already,” Collins said.

SANDAG, the regional planning agency, brought 450,000 cubic yards of sand to Imperial Beach in October as part of the Regional Beach Sand Project.

According to project engineers from Moffatt & Nichol, once the sand dissipates, the material may move as far north as the mouth of San Diego Harbor and as far south as the U.S.-Mexico border.

SANDAG has not answered repeated phone calls for comment on these concerns.

The City of Imperial Beach declined to state its position until the city could have more conversations with estuary staff.

"My reaction is to get their thoughts directly and go from there," said City Manager Gary Brown. "The estuary has had blockage problems at this river mouth for years so I'm not sure how this is any different than it's been for a long time."

Collins, a U.S. Fish and Wildlife Service employee, said sand has closed the river mouth twice in recent history–once in 1984 and partially in 2010.

Warm waters during a 1983 El Niño generated extreme sea levels and storms that flooded areas of the city near the estuary and ocean.

Damage caused by those storms contributed to the closure of the Tijuana River the following year, said a study by Joy Zedler published by the Ecological Society of America.

From April to December 1984, a lack of tidal flushing decimated cordgrass. As a result, the endangered light-fooled clapper rail lost its nesting habitat, food and protection from prey.

“This salt marsh-dependent bird either died or emigrated when nontidal conditions altered their habitat,” the study stated.

Closing river flow can cause water to be too salty or too fresh. The result can be a lack of oxygen or nutrients in the water, pollution and eventually a die-off of plant and animal species, said estuary researcher Jeff Crooks.

“The bird population just crashed after that; they recovered, but it took some time,” he said.

The estuary, specifically the Oneonta slough near Seacoast Drive homes, hosts the second-largest population of the Light-Footed Clapper Rail in the world, Crooks said.

Support to respond if sand stops river flow is much different from 1984, Collins said.

The area received National Wildlife Refuge federal protection in 1981, and in 1984 there was no Visitor Center or on-site staff and less monitoring.

Today estuary staff can tell if the river is blocked with instruments that give real-time indications of salinity, tidal flow, water and dissolved oxygen levels and more.

Once permits are approved and heavy equipment is in place, the river could be reopened within a matter of days, Crooks said.

When a large winter storm pushed sand into the river’s path in 2010, crews using heavy equipment were able to clear the way within a matter of days, Collins said.

If sand disrupted or stopped flow of the river tomorrow, Collins said, a plan is in place to call the Army Corps of Engineers and San Diego Regional Water Quality Control Board and request emergency permits, but the estuary doesn’t have the money to carry out the dredging work, Collins said.

“At this stage, we’re cautiously keeping an eye on it, and if we do think we’re going to have a problem with it, we’ll pursue discussions with SANDAG, [because] our budget is not enough to do anything right now,” he said.

Estuary management also would need to call state regulators since threatened or endangered species may be impacted.

“It’s possible you could have least terns and snowy plovers nest near the project site,” Collins said.

In the past, the river mouth has naturally moved or closed, and sediment from across the 1,750-square-mile watershed replenished local beaches, Collins said.

But dams and other man-made action have changed the river’s characteristics, polluted the water and taken away much of California’s coastal wetlands.

“It’s very difficult to let it do that now for all sorts of different reasons,” Crooks said. “The water isn’t clean and it needs to be flushed out, and because of what we're managing for now, it needs to be open.”

The Tijuana River National Estuarine Research Reserve is the largest remaining coastal wetland in Southern California, providing habitat to endangered species and more than 370 species of birds, so the critical habitat cannot afford closures that may have naturally occurred in the past.

Since the Tijuana estuary is so unique, though a closure would be unfortunate, it may provide valuable research data, he said.

Using Jet Skis, GPS devices and other instruments, Scripps Institution of Oceanography professor Bob Guza studies how sand is distributed on San Diego beaches and teaches courses on how waves and sand interact at the coast.

Like Collins and Crooks, Guza thinks there is a potential for sand to close the river mouth. A chance exists flooding could occur upstream if the mouth is closed, and a chance water will find another way to the ocean or punch through the sand and reopen the river mouth if there is heavy river flow.

Predicting whether that happens is like predicting the weather a month ahead of time, Guza said.

“You can’t make a prediction any more than you can make a prediction about what the temperature’s going to be in a few months,” he said. “The distance is not so far that it’s impossible. It’s close enough, and that’s a lot of sand. 450,000 cubic yards is a lot of sand.

“Is it going to clog the mouth? I don’t think it will actually—but that’s speculation.”

Guza said he and graduate students have been on the beach in IB to quickly monitor the recent replenishment project but can only make fairly simple observations: The sand is moving, no big storms have moved the sand very far away and the beach is wider.

Only thorough monitoring—to observe where sand moves after it hits the shore and disappears under the waves after a replenishment project—can that question be answered.

And that requires time and money, Guza said. In most instances, that money goes to sand, not research.

Even if sand closed the mouth of the river next month, where the sand came from cannot be proven without studies like the kind Guza is conducting in Solana Beach and Cardiff, one of eight beaches to receive replenishment as part of the Regional Beach Sand Project.

“If it happens, we won’t know for sure what caused it because nobody’s making the detailed observations,” he said.

Ed Sorrels February 02, 2013 at 05:43 AM
Long shore transport has been occuring since god know's when, Mostly it is to the north but from time to time it will move it south and block the channel for the Tijuana river. With the Rodrigues dam upstream there no longer any real flushing events like ancient times but most probably the sand will again move to the north and clear the channel. I wonder if anyone has ever studied the effect of groins in the imperial Beach area and their probable effect on longshore tranmsport of sand. No LIbi, the deposit of sand on our beach is an ongowing thing. With the daming of the tijuana river we no longer have our natural sand maker from the river and north along the coast which gave us Imperial Beach, the strand and most of coronado in years long past. We disturbed the natural order and now we must use artifical means to create sand for our beaches.
Serge Dedina February 02, 2013 at 10:01 PM
Hey Everyone: Just the point is here-is that taxpayers paid up to $7 million (IB used redevelopment funds for a lot of the studies etc--and at one meeting we had 27 people asking the city not to use redevelopment funds to pay for the project studies) to pay for sand to protect public infrastructure from along IB's developed shoreline--it wasn't needed south of the end of Seacoast Drive --at all. However, the planners miscalculated the north-south longshore current, so instead a large portion of the sand is moving south instead of now and is now going to fill in the rivermouth. Or--the sand is migrating to exactly where it wasn't needed. So in essence about 40-50% of the project funds were in effect wasted--up to $3 million. This is why we have advocated for the reinstatement of the Tidelands Advisory Committee--so that we can include local "experts" or stakeholders to provide input on these types of projects. There is a logical wisdom among resource users that in most or almost all cases our City officials completely ignore. And we need City staff and council members who really truly understand why we need our city committees back and the importance of real public participation in project planning to make sure that these disasters don't happen in the future.
Telling It Like It Is February 02, 2013 at 11:53 PM
The Tidelands Advisory Committee did see this project and did have input on it.
Jon Hall February 03, 2013 at 09:38 PM
Love it --- typical bureaucratic response --- how many fingers can be pointed ... Ed --- the natural beach north of the mouth is pebbles --- always was --- until, of course, the *natural order* was disturbed by greedy humans building where they had no business being Guess next time SANDAG wants to re-create the tidal zone they should consider hiring a few people who actually understand things work ...
Serge Dedina February 04, 2013 at 03:31 PM
This project was presented to the council and the public after the TAC was disbanded. The TAC was disbanded precisely because we attempted to use it as a forum to discuss the impacts of various ill-conceived sand projects. City staff attempted to limit public input and so did the TAC chair on other hearings on sand projects. Also--it is hard to have a serious discussion of public issues and call for accountability and transparency in government when members of our community hide behind anonymity rather than have the courage to use their own names when discussing public issues. How can we ask our government officials to be more transparent if we are not willing to be transparent.


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