City manager gives update on Ellis Lake improvements
Earlier this week, Marysville City Manager Jim Schaad spoke to the Yuba Water Agency Board of Directors about recent efforts to improve the water quality of Ellis Lake in Marysville.
After receiving final approval in early February from the city council for a plan to clean up Ellis Lake, the process to improve water quality at the lake began in mid-march.
That approval from the council allowed Schaad to execute a grant agreement with Yuba Water Agency that allowed for the city to remove carp from the lake and apply a phosphorous sequestration agent (Phoslock) into the lake.
As a result of the authorization, the city agreed to a professional services agreement for $71,700 with HDR Engineering, Inc., to remove common
carp and a $53,250 contract with Aquatechnex Inc. for the application of the Phoslock, the Appeal previously reported.
According to the city, the water at Ellis Lake had accumulated high levels of phosphorus that feed harmful green algae blooms which negatively impact the entire ecosystem. The lake also had a “steady increase” over time of the invasive fish species Cyprinus carpio, which have stirred up lake sediment which causes Ellis Lake to experience high levels of phosphorus, the
city previously said.
To resolve these issues, a two-phase cleanup process was initiated. This first phase involved the removal of the carp from the lake. The second phase was the application of the Phoslock agent to help clean the water.
Phoslock is a modified clay technology that “specifically inactivates (locks) available forms of phosphorus in the water column. Phoslock is certified for use in drinking water and poses negligible risk to the aquatic environment. Phoslock has been successfully
and safely applied to inactivate phosphorus in hundreds of ponds, lakes and reservoirs in over 20 countries,” the city previously said.
On Tuesday, Schaad gave an update to the Yuba Water board concerning the effectiveness of the city’s efforts.
He said after a four-day removal process, 253 “large carp” were taken out of the lake.
“In the process they also captured a significant number of other species,” Schaad said. “Large-mouth bass were the primary species. Caught and released, 288 large-mouth bass
were found in the lake. Quite a thriving lake, surprising to me somewhat.”
Schaad said other fish were found, including catfish and others. Another surprise for Schaad was the amount of Phoslock that was needed in order to help clear the lake. He said after Aquatechnex came out prior to treatment and measured the water quality, phosphorus levels were at about a third of previously measured levels.
“This is speculative, but I believe what may have happened is during the winter months, we release significant amounts
of water out of the lake … and that may have diluted the phosphate levels,” Schaad said. “When Aquatechnex came out, they did not need to use as much of the treatment. They had originally expected to treat with 13,000 pounds. They ended up treating with about half of that. The balance of that is at our corporate yard and we’re holding on to that to see what the phosphorus levels are after treatment.”
Schaad said once the city measures the phosphorus levels again, then it will decide
on whether to use the remaining Phoslock treatment or return it and get reimbursed.
“I feel (it was) successful. Did we get all the carp? Probably not. Did we get a good sizable amount of carp? Yes. I think keeping in mind the goal is to reduce phosphate levels, I think we’re on a good track. We won’t know until we have those readings,” Schaad said. “… Next steps will be to continue to monitor the phosphorus levels. And we have some choices there. If the phosphorus levels start to build up again, there are some new products out there that we may be able to treat and minimize the phosphorus entering into the lake through the well water, so that is one option. I still do want to pursue improving the circulation in the lake because that is another component that can cause, basically, stagnate the water and encourage algae growth.”
He said the city will be working with “various regulators” to see what it would take to “circulate water through the lake from the rivers” and what the cost might be. He said that a decision will be made with a focus on how much it would cost to continue to simply treat the lake versus other options.
Yuba Water Board member and Yuba County District Five Supervisor Randy Fletcher said he was happy to see progress made on an issue that has gotten so much attention in the Yuba-sutter area.
“So many people in this community travel, see and touch in that particular area. So, I can’t be more pleased that you’re in this venture to really, really clean it up,” Fletcher said. “Interestingly enough,
I get as many questions about this as I do the entire fifth district. … I really look forward to the day when the city council all decide to go swimming at the same time in Ellis Lake to show it’s ready and available to the public.”