Julia Lew, a water treatment plant specialist, was the special guest speaker at the Okanagan Basin Water Board’s annual general meeting last Friday in Kelowna. Lew talked about the many problems caused to the Lake Mead system since invasive quagga mussels were first discovered back in 2007. (Keith Lacey photo)
What’s happened in Vegas will hopefully stay in Vegas and not ever come to the Okanagan Valley when it comes to invasive quagga and zebra mussels.
That was made abundantly clear following the keynote address at last Friday’s Okanagan Basin Water Board (OBWB) by a woman who has been at the forefront of trying to fend off the devastation caused by invasive mussels over the past eight years in Las Vegas.
Julia Lew is a certified water treatment plant operator with the South Nevada Water Authority (SNWA) with more than 20 years of experience, specializing in treatment plant optimization.
The SNWA provides drinking water to almost two million Nevada residents and another 40 million tourists who flock annually to Las Vegas.
Employees with the SNWA have had to make fighting invasive mussels a big part of their mandate since millions of quagga mussels were confirmed in Lake Mead, which provides drinking water for all Las Vegas residents and visitors, said Lew.
The main issues, from a water delivery perspective, have been the potential clogging of water intakes and protection of water treatment infrastructure, said Lew.
In many areas where mussels exist, there is one reproductive cycle per year and one female can produce one million eggs, but the warm water temperatures in Lake Mead has resulted in six to eight reproductive cycles per year, she said.
Invasive mussels were first discovered in lakes in the United States, almost exclusively on the East Coast, as far back as 1986, said Lew.
The mussels, and many problems they cause, have spread across huge swaths of lakes, rivers and streams across the U.S. and finally arrived in Lake Mead in the spring of 2007, she said.
To its credit, SNWA management took immediate action and started holding symposiums and workshops across the state and region and quickly formulated a plan to try and control their spread, she said.
Once invasive mussels have filtered into a water system, they grow and spread rapidly, she said.
As a manager with treatment plants in a large metropolitan area like Las Vegas, the decision was made to take action to ensure the mussels couldn’t clog and contaminate treatment plant infrastructure and intake areas of two huge treatment plants that provide drinking water to millions of people, she said.
One common misconception about invasive mussels, she said, is that they grow exponentially forever.
What happens in reality is there is a massive amount of mussels that infiltrate a water system for many years, but then things level off and there’s isn’t massive growth, she said.
However, you can’t eliminate them and the costs to control the damage they cause continue for years and decades to come, she said.
In Las Vegas, the government paid to build a “pilot plant, which is basically a mini treatment plant” in large part to find better ways to control invasive mussels, said Lew.
To protect intake areas leading to the treatment plants, the SNWA constructed huge steel screens, which have to be cleaned twice a year by dive crews that use powerful pressure washers to clean the screens, she said.
“Manual cleaning is needed … it’s the only thing that works,” she said.
Despite having hundreds of million of these invasive mussels in Lake Mead, the good news is none of them have ever infiltrated the water treatment plants or affected water quality, she said.
The SNWA had tested numerous methods to try and control mussels and what worked best is a combination of chlorine and ammonia, she said.
The SNWA had to spend close to $8 million to install huge titanium chlorine and ammonia feed lines to protect intake areas at the treatment plants, she said.
Preventing invasive mussels from reaching water sources should be the goal rather than reacting once they arrive, said Lew.
“If we could go back in time, prevention would have been the way to go,” she said. “I know some think prevention is costly, but the moment you don’t have it and the mussels get in, it’s devastating. The costs once they arrive are far worse.”
The OBWB has estimated it could cost at least $43 million per year to control invasive mussels if and when they arrive in the Okanagan water system.
The SNWA now spends roughly $225,000 annually on chlorine and ammonia, between $150,000 and $200,000 annually on feed line equipment on top of other ancillary costs directly related to invasive mussel control, she said.
The OBWB has been a leader in pressing the provincial government to take direct action to prevent invasive mussels from migrating to B.C and will continue to do so, said OBWB executive director Anna Warwick Sears.
After Lew’s presentation, Warwick Sears said she realizes more than ever just how devastating these mussels really are.
“I’m gobsmacked at the level of work you have done there (Las Vegas),” she said.
The devastation these mussels would cause to the Okanagan water system would be “staggering … you have given us a huge amount to think about.”
Warwick Sears repeated that every effort must continue to be made to ensure these invasive mussels are kept out of B.C. waterways.
KEITH LACEY
Osoyoos Times
