Lake turnover is common occurrence that happens with all lake water most often in the fall and sometimes the spring with temperature changes. When a lake turnover occurs some may notice what is described an earthy or musty taste and smell to the drinking water. The compounds that cause the taste and odor issues are not considered a risk to public health and do not diminish the ability of a water provider to meet water quality guidelines for health standards.
Lake turnover occurs when the water from the top of the lake changes places with the water on the bottom of the lake. With fall temperature changes, as water cools on top of the lake,
it becomes more dense, causing it to sink. This dense water forces the water from the bottom to rise. Lack of water movement in a reservoir can exacerbate the turnover effect and increase
the taste and odor increasing compounds. For Lake Springfield, the lack of water movement and reduced thermal load in the reservoir including with nonoperation of Dallman Power Plant Units 31, 32 and 33, appears
to correlate with exacerbation of the higher levels of algal compounds and turnover in Fall 2021.
To ensure CWLP drinking water is safe to drink, and meeting or exceeding all regulatory standards, the utility works hard to meet customer expectations for the water’s aesthetic characteristics – its taste, odor and appearance. CWLP feeds powdered activated carbon to reduce taste and odor compounds in the finished drinking water. To further address the taste and odor issues, the Water Plant can increase its Powder Activated Carbon in the treatment process and alter the depth of its raw water intake in an attempt to minimize the issue. Water Distribution can also enact distribution system flushing to move water.
Customers sensitive to the taste and odor issues may find drinking chilled water from a pitcher after refrigeration may be more pleasing. Customers with taste and odor issues can make a report to Water Dispatch at 217.789.2323 ext. 2 or email publicinformation@cwlp.com.
Lake Circulators “Solar Bees” Proposed To Improve Lake Water Health
On March 9, 2022 CWLP and Ixom Watercare presented information to members of the Springfield Lake Shore Improvement Association members on the use and placement of circulator equipment, “Solar Bees,” on Lake Springfield—a measure proposed to address lake turnover and resulting water taste and odor issues as occurred last late summer to fall.
From the presentation, one question asked not anticipated was if this area of the lake where the circulators would be placed would become a no wake zone. The answer to that question is no. There is not a plan to dedicate this area of the lake as a no wake zone with placement of any lake circulators.
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At the February 1, 2022 City Council meeting, CWLP and Ixom Watercare presented information on lake circulation equipment as a potential solution to alleviate impacts of lake turnover and overall improve lake water health.
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On September 21, 2021 City Council Meeting, CWLP presented information on status of lake turnover, impacts and potential solutions.
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Drinking Water Taste and Odor FAQS
What is making my water taste or smell earthy or musty?
Lake turnover, a normal event for surface water supplies, occurs when the water from the top of the lake changes places with the water on the bottom of the lake. With fall temperature
changes, as water cools on top of the lake, it becomes more dense, causing it to sink. This dense water forces the water from the bottom to rise. Lack of water movement in a reservoir
can exacerbate the turnover effect and increase the taste and odor increasing compounds. The lack of water movement and reduced thermal load in the reservoir including with nonoperation of Dallman Power Plant
Units 31, 32 and 33 appears to correlate with exacerbation of the higher levels of algal compounds and turnover.
With lake turnover, algal compounds from naturally occurring blue green algae result in a change in the taste and odor. The algal compounds, Geosmin and Methylisoborneol (MIB) found in naturally occurring blue green algae have been identified as the cause for the taste and odor.
On September 21, 2021, CWLP presented information on status of lake turnover, impacts and potential solutions.
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Is my water safe to drink during lake turnover?
Yes. The algal compounds do not impact drinking water safety. Although the water can have an off taste or odor to some described often as earthy or musty, it is safe to drink. Chilling tap water before drinking can reduce taste issue.
What does CWLP use to make the water taste better?
The Water Plant can increased its Powder Activated Carbon in the treatment process, alter the depth of its raw water intake and conduct plant washouts to address when the issue arises. Water Distribution crews have also completed one phase of system distribution system flushing and a second phase is underway now. Year-round CWLP and its partners implement Best Management Practices in the Lake Springfield Watershed to reduce runoff and nutrients into the reservoir, which include those that cause algal compounds to increase.
Is there anything I can do to make the water taste better?
Chilling tap water before drinking can reduce taste issues for some. Adding a slice of lemon to the water sometimes helps as well. A home charcoal filter may help but it is not likely to remove the taste or odor entirely. The charcoal in a home filter uses the same material (granular activated carbon) as the water treatment plant does, which is only able to resolve most but not all, of the taste and odor causing compounds.
Where can I report water issues or ask questions?
Contact our 24-hour Water Dispatch at 217.789.2323 ext. 2 and make a report with your contact information and address or email PublicInformation@cwlp.com.