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Poison for Escaped Aquarium Plant
Though they may appear to be winning the weed war in the Delta, two invasive, non-native plants - water hyacinth and Egeria densa (aka Brazilian elodea or common waterweed) - may soon come under serious attack from the Department of Boating and Waterways. In April, the Regional Water Quality Control Board issued an NPDES permit, that will allow DBW to start applying herbicides, as soon as U.S. Fish & Wildlife and the National Marine Fisheries Service finish their review of the permit. Last year, Waterkeeper sued to stop the department from spraying water hyacinth without a permit. Pesticide industry and invasive plant experts opposed the need for a permit, on the grounds that the EPA had already approved the herbicides. But after the 9th Circuit Court of Appeals ruled in March that anyone spraying pesticides into a waterway needs a permit under the Clean Water Act, the State Water Board decided to follow suit, and required the department to apply for a permit to kill the weeds. Once the federal agencies issue their opinions, says the department's Pat Thalken, the agency hopes to begin its eradication efforts.
Unlike water hyacinth, which floats on the surface and can be killed by having its giant leaves sprayed with herbicide, Egeria densa, a lush, fernlike, common aquarium plant, roots at the bottom of waterways and can only be eradicated if herbicides are put directly into the water. The plant, probably introduced some decades ago when someone dumped an unwanted aquarium, grows to 12 feet tall and forms a dense canopy in the water column, making some Delta waterways impassable. Egeria is almost impossible to remove by hand because broken-off clumps can fall to the bottom and root, allowing the plant to persist and spread. Wave action from boats has a similar effect, according to UC Davis Egeria expert Lars Anderson.
While enviros are concerned that dumping herbicides into the water will also harm sensitive fish, native plants and invertebrates, Anderson argues that Egeria itself is seriously impacting Delta ecology. "Egeria interferes with waterfowl and their ability to get at their normal food base. It affects water temperatures and dissolved oxygen and forms an insulating blanket in the water. It changes the entire habitat structure and outcompetes the native pondweeds."
Will water quality improve as a result of the new permit rules? Waterkeeper's Jonathan Kaplan admits that in the short term, things may just be "business as usual" but says that in the long run, he expects to see a significant difference. "For the first time ever, the ag and vector control industries are accountable. Basically, they've been operating in the dark. For the first time, the public will see exactly what they are doing and the impacts they're having." Kaplan says that under the conditions of the permits, anyone discharging pesticides into the state's waterways will have to monitor water quality to find out how much toxicity and contamination a specific pesticide causes. Depending on the results, says Kaplan, permits could become increasingly stringent. The other milestone, he adds, is that dischargers will have to examine all alternatives to chemical control. "Some people are out there spraying just because they don't want to see green stuff in the water. Having to get a permit adds another level of burden. So far, we've had special rules for special people. Those days are gone." Kaplan admits that in some cases - i.e. Egeria - there may not be alternatives to chemical eradication. "But even if we find alternatives to some, we'll be better off."
Contacts: Waterkeeper (415) 461-2299; Pat Thalken: (916) 255-3103; Lars Anderson: (530) 752-6260 LOV
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