UPDATED April 18, 2020 by Dave Neuswanger
Based on 2018 and 2019 analyses of total phosphorus and chlorophyll-a, I am very pleased to report that July/August water quality in Teal Lake has improved dramatically since the drought ended in 2013. I can also report that Lost Land Lake looks even better than Teal, based on our resumption of sampling at Lost Land in July/August of 2019. In this time of heightened concern about human health during the COVID-19 pandemic, it is comforting to know at least one important element in the quality of our lives is better than ever.
Thanks to QLIA Water Quality Program Leader Bryan Neuswanger and Teal Lake Water Quality Monitor Carol Jarzyna, Teal Lake water quality monitoring resumed during the summer of 2018. Carol learned from Bryan how to collect water samples, which were then shipped to the State Lab of Hygiene for analysis (paid for by Wisconsin DNR) of total phosphorus concentration (a vital aquatic plant nutrient) and chlorophyll-a concentration (an index to the biomass of planktonic algae) in the uppermost 6 feet of the water column. Results from these tests should enable WDNR to remove Teal Lake from the list of “Impaired Waters” under Section 303(d) of the Federal Clean Water Act of 1972 during the next assessment cycle ending in 2020.
In determining whether or not a waterbody is “impaired,” WDNR looks at data from the most recent 5 years of sampling during the months of July and August when the production of planktonic algae is at its annual peak. WDNR’s 2018 “assessment cycle” for Teal Lake included the years 2012 (drought), 2013 (drought ending), 2014, 2015, and 2016. The 2020 assessment cycle will include only data from 2013 through 2018. Therefore, 2018 data will replace 2012 data in the summary calculations. Average total phosphorus decreased from 32.0 ppb (parts per billion) in July/August 2012 to 17.9 ppb in July/August 2018. Average chlorophyll-a decreased from 28.2 ppb in July/August of 2012 to 14.0 ppb in July/August 2018. The near 50% decline in these indexes of pollution between 2012 and 2018 will be more than enough to drop the 5-year averages below the threshold level for designating Teal Lake as “impaired” under WDNR’s listing protocol. As I have stated previously, Teal Lake is JUST FINE.
I believe the 2018 data are more representative of the norm at Teal Lake than during the drought of 2012. The 2019 data for Teal Lake confirm that 2018 was not an anomaly, as total phosphorus in July/August 2019 averaged 18.6 ppb, and chlorophyll-a averaged only 8.9 ppb. Our most recent data reflect the true mesotrophic nature of Teal Lake, despite its eutrophic condition during a severe drought. These data also suggest that Teal Lake property owners are doing a good job maintaining their septic systems and limiting the unnecessary use of lawn fertilizers.
I am also pleased to report the resumption of full-spectrum water quality monitoring in Lost Land Lake in 2019. Total phosphorus and chlorophyll-a had not been monitored in Lost Land for several years because WDNR funding assistance for expensive laboratory testing was limited. But Bryan Neuswanger worked to get Lost Land Lake back on WDNR’s list of waters approved for funding. In February of 2019, Bryan received a letter formalizing WDNR’s commitment to fund our laboratory analyses in 2019 from Mr. Kris Larsen, Citizen Lake Monitoring and Invasive Species Specialist for WDNR, who works out of WDNR’s Service Center in Spooner.
At Lost Land Lake, total phosphorus in July/August 2019 averaged 21.0 ppb, and chlorophyll-a averaged only 6.1 ppb, allowing us to classify Lost Land Lake as mesotrophic (of moderate biological productivity) also. June-August 2019 Secchi disk visibility (a measure of water clarity) averaged 6.5 feet in Lost Land Lake and 5.8 feet in Teal Lake. Both were near optimal for the fish species of greatest interest on our lakes — walleye. If the water was any “cleaner and clearer,” Lost Land and Teal lakes would not be as good for fishing. We are clearly in the “sweet spot” for a combination of aesthetics and quality fishing.
Anglers on both Teal and Lost Land may be interested to know that 2019 temperature and dissolved oxygen profiles continued to show that Teal Lake typically stratifies in mid summer, reflected by a rapid decline in both temperature and dissolved oxygen between the depths of 15 and 18 feet, with almost no dissolved oxygen at depths greater than 18 feet. Fishing at depths greater than 18 feet in Teal Lake in mid summer could be a waste of time as fish seek warmer, more well-oxygenated waters at depths of 15 feet or less. Lost Land Lake, on the other hand, is so shallow and wind-swept that significant density layers are unable to form, resulting in water that is almost the same temperature from top to bottom, with enough dissolved oxygen near the bottom to support fish activity everywhere in the lake. This may be good for the fish, but because they could be ANYWHERE, it also poses a challenge to anglers. That’s a problem I am happy to try to solve 🙂