Research summary · Restorative Lake Sciences · Oceana County, Michigan
Silver Lake 2023 Biochar Efficacy Results
Restorative Lake Sciences reports that biochar filters placed in Silver Lake’s drains and on docks and boats in 2023 coincided with declines in total phosphorus and suspended solids at the monitored drains, and that harvested filters removed approximately 1.4 tons of phosphorus during the 2023 season.
Phosphorus removed by harvested biochar filters, 2023 season
p. 4, 29Monitored drains showing declines in TP and TSS
p. 4, 29Water quality sampling sites selected from a 2021 storm survey
p. 16Drain filters installed, permitted by Michigan EGLE
p. 16Key findings
What the report says, step by step
Each finding is taken from the document, with page references. Charts are rebuilt from the report’s own figures.
About 1.4 tons of phosphorus captured
A recent analysis of the harvested biochar filters revealed that approximately 1.4 tons of phosphorus were removed during the 2023 season.
p. 4, 29Filters where runoff enters the lake
Biochar in the drains resulted in a decline in total phosphorus and total suspended solids at Hunter Creek, the State Park, Taylor Road, Dunes Vista and Lollygagging. Forms of nitrogen such as ammonia were also reduced at all of these drains.
p. 4, 29From storm survey to installed filters
Eight sampling sites were chosen after a 2021 rainfall event. In 2022 the report recommended filters on all critical drains; they were permitted by EGLE and installed in June 2023.
p. 16Lower nutrients, clearer water, more plants
Nutrients in the water column in summer 2023 were significantly lower than in recent years, attributed to these efforts and to reduced runoff. Submersed aquatic vegetation is increasing due to higher water clarity.
p. 4A multi-year effort
The authors say significant improvements will take years, and loading rates will be calculated once more flow data is collected in 2024.
p. 4, 30
The Biochar applications are resulting in reduced nutrients and improved clarity with lower algal concentrations.Restorative Lake Sciences, Silver Lake 2023, p. 30
About this report
Authors, date and method
- Authors
- Restorative Lake Sciences (Spring Lake, Michigan).
- Date
- November 2023 (as stated in the report).
- Method
- Annual lake report covering basin water quality (2018–2023), drain water quality (2022–2023) and aquatic vegetation (2023). Biochar filters were permitted by Michigan EGLE and installed in critical drains in June 2023; eight sampling sites were selected from a 2021 rainfall event survey.
Independent field evidence of what biochar filters do for water quality, from lake scientists at Restorative Lake Sciences. Cite the original authors when using these findings.