War of the Weeds : Carlsbad Battles Invasion of Lagoon by Water Hyacinths

Doug Duncanson stood above Buena Vista Creek last week and took a good, hard look at the enemy.

There, completely clogging the channel leading into Buena Vista Lagoon, were hundreds of water hyacinths, their waxy green leaves glistening in the early-morning sun. The lush, floating carpet looked more decorative than dangerous. But Duncanson, Carlsbad’s park superintendent, was not deceived.

“It actually is pretty. But it can be a real troublemaker for us,” he said as two of his men opened fire, pelting the plants with a fine stream of herbicide. “We’ve got to get it before it takes over.”

Duncanson was supervising the county’s first-ever attempt to eradicate the Eichhornia crasipes , an aquatic weed that has earned its reputation as a persistent pest by choking waterways around the world.

A native of South America, the fast-spreading plant has no natural predators in the United States. Nothing short of poison impedes its growth, and it develops at an alarming rate, depleting the water of oxygen and of nutrients upon which many other aquatic species depend. In 10 days, it can double in area; in 50 days, three plants can multiply into 3,000.

“It’s a green monster, believe me,” said Larry Thomas, the Water Hyacinth Control Program supervisor for the state Department of Boating and Waterways in Sacramento. “It’s a nice-looking plant, dark green. People have a hard time just throwing it in the garbage. Next thing you know, public agencies are spending millions of dollars trying to get rid of it.”

For seven years, Thomas has been battling the dread weed in the Sacramento-San Joaquin River Delta, where it wreaked havoc on the recreation industry, the local marinas and the agricultural community.

“It gets so thick you can’t use (the water) for boating, you can’t fish, you can’t water ski. You can’t push your way through it in a boat. It burns engines up,” he said, drawing on his long experience with the plant’s bad habits.

By contrast, Carlsbad park officials, who have turned to Thomas for advice, say they had never seen the water hyacinth before it turned up in San Diego County earlier this year. And they concede that, if not for a local resident’s concern, they might still be unaware of the plant’s takeover attempt in Buena Vista Lagoon.

Linda Scott, a retired businesswoman who has lived near the lagoon in Oceanside for 25 years, recalls that she was taking a walk one day last spring when she spotted a single water hyacinth floating in Buena Vista Creek.

“I saw that little devil down there. Somebody probably was just driving by and threw it out there for fun,” said Scott, 47. But she knew better. She had encountered the plants before, and she knew how they could grow.

Determined to stop the spread, Scott said she began calling state fish and game officials and journalists, but no one returned her calls. And each day, as she walked by, she saw the water hyacinth had gained a little more ground.

“It was really frustrating. It was a situation where I could have ripped it out myself if I had hip boots,” she said. “I was in tears. To me, it’s really a tragedy.”

So Scott did something she had never done before. She wrote a letter last summer to the governor, and copied it to several local and state politicians.

In the handwritten letter, she noted that her own monitoring of the area indicated that the plants had more than doubled weekly and now had entered the mouth of the lagoon. She lamented that a blue heron that nested every year in the reeds at the lagoon’s edge had instead taken residence on the roof of a private home across the freeway.

“He can no longer get into the water,” Scott wrote. “I have no children. But tears come to my eyes as I write this letter knowing that those children born today will not see the beauty of the Buena Vista lagoon and the wildlife it supports even as they approach 1 year old. . . . Please help me, governor. But not for me, rather help me for your children’s children.”

She signed her name and added this postscript: “I’m not an activist. I’ve never written a letter like this. And I feel like I’ve hit a block wall. Please.”

It was that letter that finally drew some attention. Carlsbad officials contacted Scott, who took them to the banks of the Buena Vista Creek, where a thick layer of weeds completely hid the water.

By that time, there were signs throughout the lagoon that the weed was taking hold--floating green islands bobbed alongside the ducks and other waterfowl that make the lagoon their home. Now, officials estimated that 10 to 20 acres of the 100-acre lagoon are covered with the weed.

Thomas, the state waterways official, prescribed an herbicide called Weedar, which contains the chemical 2,4-D. He also gave Carlsbad officials some advice.

“It will take over unless it’s controlled,” he recalls saying. “The longer you wait, the more money, effort and chemicals will have to be used. It’s going to have to be done. So get on it and do it.”

This is not the first time that nature has threatened to clog the Buena Vista Lagoon. In 1983, the state spent $1 million to dredge the lagoon, which was being choked with silt.

It also is not the first time the county has struggled with South American aquatic weeds. For a decade before 1988, boating was banned on Lake Murray because of a pesky grass called hydrilla. Like the water hyacinth, hydrilla is classified by county agricultural officials as a noxious weed--one that tends to take over.

Half of Lake Murray was infested with the hardy weed in 1979. At times, the mat of hydrilla grew so thick that ducks walked on the lake’s surface. Authorities tried spraying various chemicals to kill it off, but, in the end, a much more hands-on approach proved to be the solution. Divers used large vacuum hoses to suck up the weed, roots and all.

Scott, the woman who first reported Carlsbad’s weed epidemic, said she wishes there was a way to avoid using chemicals in the Buena Vista Lagoon. She laments that, if only someone had listened when she first called for help, the toxic remedy could probably have been avoided.

Sharon Taylor, the pesticide reduction director at the San Diego Environmental Health Coalition, agreed.

“It’s something that could have been avoided. And, because they’ve waited so long, there’s no guarantee that the chemicals will work,” she said. Still, she said that, although she hopes that Carlsbad officials will attempt to minimize the herbicide use, she does not completely oppose the spraying.

“We would like to see pesticides not used, but there are occasions where they have to be used. This, unfortunately, is one of them,” she said, noting the damage that water hyacinths will do to the lagoon’s ecosystem if left to grow unchecked. Herbicides, she said, are “the lesser of two evils at this time.”

Carlsbad officials plan to make a second application of the herbicide in about three weeks. But, even if the poison appears to work, they will continue monitoring the lagoon for three years to guard against re-emergence. According to Duncanson, the park superintendent, the water hyacinth’s seeds can live for more than five years underwater before sprouting.