In-depth Water-Quality Investigation on Torch Lake, Antrim County, MI
By Lon Nordeen, MLSA Secretary
Based on discussions with Dr. Dale M. Robertson, Research Hydrologist, U.S. Geological Survey, Upper Midwest Water Science Center (dzrobert@usgs.gov), with input from Thomas Joseph, Torch Lake Protection Alliance Board member (torchlaketomj@gmail.com)
Photo above: Torch Lake on the bottom and Lake Michigan seen over the tree line.
Credit: Thomas Joseph
An in-depth water-quality study on Torch Lake, Antrim County, Michigan is being conducted by the U.S. Geological Survey (USGS) and the Torch Lake Protection Alliance (TLPA) to describe the water quality of the lake, quantify the amount of water and nutrients being delivered to the lake, and determine how the water quality of the lake should respond to these inputs and changes in these inputs. This study began in 2022 and is planned to be completed in 2026. Funding for this program is from the TLPA (approximately 70%) with federal matching funds to cover the rest. TLPA created a ”Keep Torch Lake Blue” program to fund the project largely from riparian donors and the TLPA Board members. Antrim County has acted as the fiduciary and supported the effort since 2022.
Torch Lake is a big, deep lake about 19 miles long and 287 feet deep, located very near Lake Michigan. Torch Lake is a very clean, unproductive lake. This is because it has very little agriculture and orchards around it, but there are concerns that even a small change in the amount of nutrients delivered to the lake could have a big impact. Torch Lake is the largest body of water in “the Elk River Chain of Lakes,” which covers 55 miles of 14 lakes and interconnecting rivers. Torch Lake receives water and nutrients from many sources throughout its entire watershed.
The USGS has been monitoring the water quality of the lake since 2023, monthly during most of the open water period. This includes describing the temperature, dissolved oxygen, pH, nutrients, and algal community in the lake. Results have shown that the lake has extremely low phosphorus and chlorophyll a (algae) concentrations. The program has included an annual review of the data and related topics in a day-long meeting supported by several local and regional organizations. Every meeting has featured guest speakers in related disciplines to help refine the project and employ best practices. The meetings are video recorded and posted on YouTube.
The USGS is quantifying the water and nutrients (primarily phosphorus and nitrogen) being delivered to the lake from surface water, groundwater, and atmospheric deposition. The USGS is developing a full hydrologic budget for the lake by quantifying each of the sources. They are estimating how much surface water is coming into the lake by installing stream gages on the Clam River and Spencer Creek, and how much is leaving the lake by installing a stream gage on the Torch River. They are estimating how much groundwater comes into the lake by installing 12 small wells around the lake and developing a groundwater model for its watershed. The amount of water entering from rain and snow is obtained from gauges placed by the North American Land Data Assimilation System. A full hydrologic budget will help determine the accuracy in each of these estimates and the relative importance of each source.
To estimate the amount of nutrients being delivered to the lake, nutrient concentrations are being measured in each of these sources of water. Routine samples are being collected in each of the major tributaries to the lake (Clam River and Spencer Creek), and less intense sampling is being conducted on a subset of the minor tributaries. Each of the small wells around the lake is being sampled quarterly. Little nutrients are expected to be delivered by groundwater because of the soils in the basin. Phosphorus concentrations are also being measured in the rainfall and snow because it is not normally sampled by other national programs. Very low phosphorus concentrations are being found, possibly because of the lake’s proximity to Lake Michigan to the west. This nutrient inventory will describe the relative importance of each of the sources and determine which of them may be best controlled. All of these data are going to be used as input to water-quality models that will describe how the lake should respond to changes in nutrient inputs to the lake and possible management alternatives.
Although Torch Lake is a very clean and unproductive lake, recently it has started to develop benthic algae around parts of the bottom of the lake, and invasive mussels have been introduced. These are two of the residents’ biggest concerns, and residents are interested in how changes in the amount of nutrients entering the lake may affect these issues. The study is being coordinated and regularly reviewed with Dr. Jan Stevenson, who is the primary researcher of the benthic algae. Dr. Stevenson’s work is funded by The Three Lakes Association.
The USGS is currently in the last year of major data collection and is developing a groundwater model for the watershed and water-quality models for the lake. They plan to complete the publication of their results in 2026.
Why is this type of study important? Although Torch Lake is one of the cleanest lakes in Michigan and is expected to have a very small amount of nutrients entering the lake, it is important to document changes in these inputs because any small change might have a big impact on water quality in the future. A small change in the watershed that may not be very important for a lake in the southern part of the state could have a dramatic change in the amount of nutrients being delivered to Torch Lake and strongly affect its water quality.
Whether you live in a home or condo on or by a lake, pond, stream, or river, you need to do what you can to protect the water. People who live a distance from a lake can still affect its water quality. Actions have been taken around many lakes by people upstream in the watershed to improve water quality and make others aware of how they can affect the water quality of their nearby lake. These actions not only include large changes such as changes in agricultural practices, reduction in point sources, and storm water management, but they also include small changes, such as storm water grates that have photos of fish on them to remind people that their actions also impact water entering the lake. Everyone needs to think about this because the entire watershed impacts the quality of groundwater, rivers, and the downstream lakes.