CVWD to begin treating for Quagga mussels—before they arrive by boosting chlorine in the water
Posted by: Aqua Blog Maven on June 25, 2008 at 6:19 amFrom MyDesert.com, two very similar stories. The first:
Coachella Valley Water District will be using considerably more than a single ounce of prevention when it begins introducing liquid chlorine into the Coachella Canal, scheduled to begin July 3—a preemptive strike designed to prevent destructive quagga mussels from infesting and colonizing the waterway and its delivery system.
The district plans to release 4,050 gallons of chlorine daily into the canal a short distance from where it branches off from the All America Canal, about 10 miles west of Yuma, AZ, near the United States border with Mexico.
CVWD personnel have been monitoring the canal closely for the mollusks since they were discovered at Lake Mead in January 2007. The 123-mile Coachella Canal is free of the invasive, non-native mussels so far, but several were found in February this year in a desilting basin at Imperial Dam. Colorado River water passes through those facilities before being diverted first into the All American Canal, which serves Imperial County, then further downstream into the Coachella Canal.
Chlorine has proven effective elsewhere in killing quagga mussel veligers, the free floating larvae produced by the mollusks. A single adult quagga mussel releases as many as 10,000 larvae at a time, up to one million in a single reproductive season.
Although the concentration of chlorine will be sufficient to kill the larvae, the chemical will dissipate about a mile downstream from where it is introduced into the water, at what is known as a Parshall flume. Turbulence at the flume, which is used to measure the canal’s flow rate, is conducive to blending the chlorine with water.
The first of CVWD’s approximately 1,100 canal water customers is nearly 90 miles further downstream—and there are about half a dozen irrigators served by Imperial Irrigation District more than 35 miles away—so the chemical will not be present in any water deliveries. About 300,000 acre-feet of water is diverted into the canal annually.
The second story, which briefly discusses adding the chlorine, and then includes this, similar to the story posted yesterday:
Water officials from elsewhere testified in Washington, D.C. about the invasion of the mussels at a hearing of the House Natural Resources Committee Subcommittee on Water and Power. Water authority officials complained that the quagga mussel, a thumb-sized mollusk, can clog water pipes and facilities and wreak havoc on habitats.
“It’s significant. They grow very quickly,” said Ric De Leon, water systems operations manager for the Metropolitan Water District in Southern California, which includes Riverside County. “If they spread beyond where they are, it will be costly.”
The officials urged Congress to provide federal funding for more research, to develop a regional plan to address the problem and help agencies rid their water systems of the mussels. De Leon said his agency spends $10 million to $15 million a year to address the problem.
“We are coping with the problem - for the moment,” said Ronald Zegers, director of the Southern Nevada Water System, who called it the “most serious nonindigenous” pest introduced in North American freshwater systems.
Read the full text of the first article from MyDesert.com by clicking here; the second article by clicking here.
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