ANTIOCH, Calif. — Over the past several months, a thick carpet of green has spread across many Delta harbors and even open channels, making them the latest victims of California’s historic drought.
From the air, the expanses of dense vegetation can pass for a lush golf course or lawn, but there’s nothing innocuous about these floating weeds that are imperiling everything from recreational boating and fishing to international cargo shipments to bird migrations.
“We’ve never had it this bad,” said Cindy McClelland of Brentwood’s Orwood Resort, which had to constrict the mouth of its harbor with a floating barrier after currents and wind from a couple of big storms left the facility awash in weeds. “The whole harbor was completely filled in.”
One of the biggest culprits is the water hyacinth, a fast-growing native of the Amazon basin that is finding optimal conditions amid California’s three-year drought.
With the drastic decrease in snowmelt from the Sierra Nevada, there is less cold mountain water runoff moving through the Delta into the ocean, and that has caused river temperatures to rise.
In addition, with less water flowing into the Delta, currents aren’t strong enough to push the weeds downriver and into the ocean.
Capable of doubling in size every 10 days, water hyacinths grow together to form thick mats during their peak late summer season. Come fall, the matted masses break apart and, propelled up and down the San Joaquin and Sacramento rivers by wind and tides, they scatter seeds — up to 5,000 per plant — that remain buried in sediment where they can remain viable for up to 20 years.
These characteristics make it impossible for the state’s herbicide spraying to kill all the water hyacinths; the state Division of Boating and Waterways emphasizes that its goal is simply to limit the plant’s spread.
And this season, Delta residents are saying the proliferation of the invasive plant is one for the record books.
The water hyacinth confines some vessels to their slips, routinely blocks marinas’ boat launch ramps and as creates more worries for those monitoring the health of the Delta’s ecosystem.
Although Antioch depends largely on the tides to pull the sheets of plants out of its boat launch area, city workers must use a small rototiller-like machine from time to time to free vessels from their berths at the marina.
Chris Lauritzen estimates his five employees have spent hundreds of man hours removing weeds that continue to drift into the Oakley yacht harbor he owns.
“We never have enough people to get ahead of it,” Lauritzen said.
McClelland estimates that for a couple of weeks, Orwood Resort was losing launch fees from multiple fisherman every day because they couldn’t take their boats out.
“Absolutely the worst year ever” is how cruise boat operator Frank Morgan describes the situation in Discovery Bay, where he had to summon the harbormaster to clear a path through the weeds so he could take passengers on a New Year’s Eve outing.
But it’s the potential hazards to life and limb that really concern him. If a child fell overboard right now, the child would disappear under a covering of weeds so dense that it would be very difficult to spot him or her, Morgan said.
What’s more, vessel operators — especially those in speeding bass boats that sit low in the water — might not see floating logs or other large obstructions when they’re surrounded by vegetation, said Morgan.
Oakley’s Big Break Regional Shoreline hadn’t had much of a problem with the plants until last fall, when it experienced the most severe onslaught since the park opened in 1995, said Mike Moran, supervising naturalist for the visitors center that the East Bay Regional Park District operates.
The agency closed its boat launch Dec. 29 because kayakers simply couldn’t paddle through the growth, and earlier this month it called for volunteer help to haul the weeds onto land.
To the east, the massive influx forced organizers of Stockton’s Christmas lighted boat parade to cancel the event for the first time in its 35-year history. As winter approaches, the pilots of big ships heading for Stockton’s port no longer can navigate the channels at night because their radar can’t distinguish between the weeds and levees or smaller vessels.
The resulting delays in cargo deliveries cost importers at least $200,000 in additional rental fees for the vessels, said Jeff Wingfield, director of environmental, government and public affairs for the Port of Stockton.
And for the second time, the port last year hired an aquatic weed harvesting company that removed more than 2 million tons of plants — roughly four times the amount it extracted in 2013, Wingfield said.
Apart from the toll that water hyacinths are taking on recreation and commerce, they pose a threat to wildlife.
The weeds conceal areas where migrating waterfowl normally would land to rest during their journey, forcing longer flights that further deplete the birds’ energy, Moran said.
By filtering out sediment in the water, they also make it harder for small fish to hide from predators, he said, adding that as the plants decompose, oxygen in the water can be consumed to levels that make it difficult for some species, such as salmon, to survive.
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Boating and Waterways is struggling to get a handle on the problem: It has just six boats and a dozen workers at its disposal to cover thousands of acres spraying herbicide on invasive plant species, an approach supplemented by the use of vessels that push the plants out of dead ends where they have collected.
In December 2013, the agency began harvesting the weed for the first time, using boats designed to chop the plants into more manageable chunks before bringing them onboard to take them to shore.
Gov. Jerry Brown has proposed adding $3.9 million to next year’s budget for more staff and equipment to step up the spraying.
Additionally, the U.S. Department of Agriculture last year introduced a multiagency approach that includes NASA using satellite imagery to identify the highest concentrations of the weed for spraying purposes.
The only way to get the upper hand is to conduct a sustained campaign, Hard said.
“You’ve gotta keep hitting it,” he said.
©2015 Contra Costa Times (Walnut Creek, Calif.)
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