Complaints of foul smell in Southern California fall dramatically
Complaints about rotten egg odor in Southern California have dropped off considerably as officials confirmed the stench came from dead fish in the Salton Sea.
The South Coast Air Quality Management District said there were far fewer complaints Tuesday compared with Monday, and most of those were in the morning.
Air samples collected in the Coachella Valley, near the Salton Sea and elsewhere clinched inspectors’ suspicions of the 376-square mile, murky body of water as the source of the pervasive smell. Atwood said AQMD inspectors collected air samples that contained hydrogen sulfide.
“We now have solid evidence that clearly points to the Salton Sea as the source of a very large and unusual odor event,” said Barry Wallerstein, executive officer of the South Coast Air Quality Management District.
How unusual? As late as Monday night, AQMD officials weren’t even sure it was scientifically possible for a malodorous scent to trek the distance the Salton Sea’s fumes did. So they asked an air-quality modeler to use sophisticated computer software to determine if it was “theoretically possible” for a stench to travel that far.
“I think we’ve shown it was theoretically possible,” said Sam Atwood, a spokesman for the AQMD. “But this is just something we did not expect.”
Inspectors ruled out landfills, oil refineries and a natural springs site as possible sources.
“The air samples were the final piece of the puzzle,” Atwood said. “Our inspectors did go out to the Salton Sea and did smell some very strong odors at the sea, as well as at the locations leading up to it.”
But it took a powerful storm blowing from the southeast to bring the stench to L.A. All in all though, Los Angeles got lucky, compared with the town of Mecca, just north of the Salton Sea, and Indio, which received larger doses of the gaseous, funky odor.
“The storm originated in the Gulf of California ... and hit the Imperial Valley and Salton Sea,” said Tim Krantz, a professor of environmental studies at the University of Redlands. “We had huge squalls and pretty heavy winds in the Coachella Valley. The winds pull the surface layers of the sea off from the southeast to northwest, and that surface water is replaced from the depth.”
And those depths are all kinds of stinky.
Experts said the winds from the Sunday night storm unsettled the fetid layers of water near the bottom of the sea, bringing them to the surface.
Andrew Schlange, general manager of the Salton Sea Authority, said that in the last week, a large number of fish died in the body of water, likely exacerbating the problem. But he said the fish die-off, which is a normal occurrence, was not significant enough on its own to explain the well-traveled odor.
Rather, he said, the storm upset an anaerobic — or oxygen-deprived — lower layer of the sea, where organic material lies slowly decomposing, releasing the noxious hydrogen sulfide gas, with its distinct rotten egg smell.
The good news was that by Tuesday the odor had greatly diminished. As of about 5:30 p.m. Monday, there had been 235 complaints about the smell, Atwood said. Since then, there have been fewer than 10, though the “sulfur-type” odor still lingered in some parts of the region.
Atwood said a meteorologist for the AQMD has looked at the thunderstorm reports, and that along with wind-measuring instruments in the Coachella Valley, they determined that winds of more than 60 mph blowing from the southeast probably blew the rank odor to the L.A. Basin.
“That’s unusual because usually the winds are blowing in the opposite direction,” he said.
The Salton Sea has lost much of its depth. It's about 50 feet at its deepest point, with an average depth of about 30 feet, Schlange said. That means it doesn’t take as potent a weather event as it did in the past to cause an upswell that sends the water near the bottom to the top.Schlange said the Salton Sea is losing much more water through evaporation than is being replenished through agricultural runoff and other sources. If water wasn’t flowing into the sea, it would lose a depth of about 4 to 6 feet a year through evaporation.
If something isn’t done to better replenish the Salton Sea, Schlange said issues with far-flung odors could be more common in the future. He said there’s a plan to do mitigation work on the sea, but money to fund it is lacking.
“All of a sudden Sunday evening, we had all these conditions that came together to allow something like this to occur,” Schlange said. “It’s occurred before, but not at this magnitude.”
-- Hector Becerra
Photo: A heron nests on a fallen tree at the Salton Sea. Credit: Lenny Ignelzi / Associated Press