Taking a Dip Into the Science of Lakes

Every month, I and the other land stewardship technicians take several measurements from Twin Lake and Lost Lake here in Oakland Township. These measurements are taken because we are a part of the Cooperative Lakes Monitoring Program (CLMP) ran by the Michigan Clean Water Corps. The CLMP is a citizen-based volunteer monitoring program that is widespread across Michigan. The program has been around in some fashion since 1974, which makes it the second oldest volunteer lake monitoring program in the nation. Lost Lake and Twin Lake have been monitored since 2018. The measurements we take are spring and fall total phosphorus, Secchi disk (water clarity), dissolved oxygen, and chlorophyll.

A fall sunset illuminates the splendor of changing leaves at Draper Twin Lake Park. Photo by Cam Mannino.

Lake monitoring is one of my favorite tasks that we do as Land Stewardship Technicians. Not only is it fun to go out on the lakes, but I greatly enjoy this task because I think the data we collect from the lakes is fascinating. In college at Michigan Tech, I worked in an aquatic ecology lab. Therefore, I am very interested in what the data we gather from each lake can tell us about how healthy a lake is.

Growing up in Minnesota, lakes and rivers were all around me, and continue to be an integral part of our identity as a state. I grew up near the Minnesota River, which is one of many rivers that flows into the Mississippi River. The Mississippi River watershed is the fourth largest watershed in the world, eventually flowing into the Gulf of Mexico. Through my parents and in school, I learned about how water travels across the land and how we can affect the health of our watershed just in our backyard. My dad especially would stress the importance of keeping our water clean. He works for the City of Minneapolis mapping the sewage and stormwater systems, which gives him a great picture of how the waterways are connected. Therefore, because of my background, I like to “nerd out” about the data we collect from the Twin Lake and Lost Lake.

Twin Lake and Lost Lake

Twin Lake (at Draper Twin Lake Park) and Lost Lake (at Lost Lake Nature Park) are small glacial lakes in Oakland Township. We monitor Twin Lake East, which is about 12 acres with a maximum depth of 30 feet. Twin Lake East is connected to Twin Lake West by a small channel accessible by kayak or canoe. There is another small lake connected to Twin Lake West also by a small channel. Twin Lake East is the only lake monitored by Oakland Township.

Lost Lake is about 6 acres with a maximum depth of 17 feet. With the very dry spring this year the lake is only about 15 feet deep. Lost Lake is at the end of its life as a lake. This means within the next several decades it will likely become more of an emergent marsh than a lake because the vegetation will cover most of the surface area of the water. Because Lost Lake is so shallow, light can easily penetrate the water column, reaching the bottom of the lake bed where aquatic plants get enough energy to grow. Lost Lake is so “weedy” because the plants are receiving plenty of sunlight throughout most of the lake. In deeper lakes, you will only find plants growing and reaching the surface along the shoreline because in the center of the lake the plants receive less sunlight at the bottom.

A special thanks goes out to Maryann Whitman for taking Secchi Disk readings at Lost Lake since 2018! You have helped us immensely in monitoring our lakes!

Twin Lake is seen on the left from the dock. On the right is the view from the dock at Lost Lake.

What is a Watershed?

A watershed is a land area that channels rainfall and snowmelt into streams, creeks, and rivers that combine with other streams and rivers to progressively drain into a larger water area. A watershed often includes many counties and sometimes can encompass multiple states or countries depending on the location.

Why Monitor Water Quality?

Lost Lake and Twin Lake are part of the greater Clinton River Watershed that feeds into Lake St. Clair. Lost Lake and Twin Lake are both in the smaller subwatershed of Stony Creek, which flows into the Clinton River. Twin Lake is connected to Stony Creek Lake through the McClure Drain. The Clinton River flows into Lake St. Clair and on down to Lake Erie. The Paint Creek also runs through Oakland Township, connecting with the Clinton River in Rochester.

As water flows through a watershed, it often picks up pollutants which then can accumulate in Lake St. Clair where the water ends up. This can have many negative effects on the ecosystem and environment depending on which and how many pollutants end up in the watershed.

Clinton River Watershed Map. Oakland Township can be seen in the upper left corner of the map. Map taken from the Clinton Watershed River Council website (https://www.crwc.org/resources/resource-library/watershed-maps).

What Each Measurement Tells Us

Each summer, we take four different measurements numerous times at Lost and Twin Lakes. Some summers, we also do an exotic aquatic plant watch survey. These measurements, when compared to other data, can tell us different information about what is happening with the ecology of our lakes. The four measurements we take are phosphorous, water clarity, dissolved oxygen, and chlorophyll.

Phosphorous

Phosphorous measurements are taken twice, once in the spring and once in the early fall. Because phosphorous is an essential limiting element for plant life, small changes in the amount of phosphorous can have drastic changes on what happens in a lake. Although phosphorous is an essential element for plant life, too much of it in the lake can cause accelerate plant growth, create algae blooms, decrease dissolved oxygen levels, and result in the die-off of some fish, invertebrates, and other aquatic creatures. Sources of increased phosphorous in waterways include run-off from lawns, agricultural fertilizers, manure and organic wastes in sewage, leaking septic tanks, industrial waste, and soil erosion.

Water Clarity/ Turbidity

Water clarity or turbidity is measured every 2 weeks with a Secchi disk. At its simplest, turbidity refers to how clear the water is in the lake. Water clarity determines how much and how far light penetrates the water. Water clarity is affected by several factors including algae, soil particles, and other materials suspended in the water. Therefore, Secchi disk readings are typically a good indicator of algal abundance and general lake productivity.

The Secchi disk is a very simple device to measure water clarity. The Secchi disk is lowered until it is no longer visible, and that depth is recorded. It then is raised until you can barely see the disk and that depth is also recorded. The average of the two depths is then taken. Above, Max is recording the Secchi depth for Twin Lake (Pictures taken by Grant Vanderlaan).

Dissolved Oxygen

Dissolved oxygen (commonly referred to as D.O.) is measured every 2 weeks using a D.O. meter. Dissolved oxygen is how much oxygen is in water. Oxygen is essential for supporting life in lakes. In the air we breathe, the oxygen concentration is about 21%, but in water oxygen concentrations are a tiny fraction of 1%. The temperature of the water determines how much oxygen the water can hold. Warm water holds less D.O. than cold water. In the summer, this is especially important because the top layer of the lake is heated by the abundant sun and is warmer than the lower part of the lake, with less dissolved oxygen. If you have ever jumped in a lake late in the summer, you will know what I mean. Therefore, in the hot summer, fish and other oxygen-dependent organisms will stay lower in the lake where it is cooler and there is more oxygen. One major concern with D.O. levels in lakes is a process called eutrophication. Eutrophication is where a lake or other body of water has excessive amounts of minerals and nutrients usually due to runoff. This leads to a depletion of oxygen in lakes and can cause a die-off of fish and other animals.

The D.O. meter is a very sensitive device used to measure the dissolved oxygen every 5ft until the depth of the lake is met. It also measures temperature at each depth. Above, Max is recording D.O. for Twin Lake (pictures taken by Grant Vanderlaan).

Chlorophyll

Chlorophyll is measured monthly in our lakes. If you remember back to high school biology class, chlorophyll is what makes plants green and is found in the chloroplasts of plant cells. Chlorophyll readings are a way to estimate algae biomass is in a lake. High chlorophyll readings indicate an abundance of algae, which is usually correlated to other processes happening in the lake such as decreased D.O. levels and decreased water clarity.

Measuring chlorophyll is a lot like conducting an experiment in college biology class. Because light and heat degrade the chlorophyll collected, the water samples are kept out of direct sunlight and placed in a cooler as soon they are as collected. First, the larger brown container is lowered into the lake at a predetermined depth and is then slowly raised, so water collects in the container. If it becomes adequately full then the two smaller containers are filled and a couple of drops of magnesium carbonate (MgCO3) are added to the smaller containers. The samples are then brought back to the Cider Mill to be further processed. Above, Grant is adding MgCO3 to one of the small container samples.

Chlorophyll Lab Processing:

Parker pushes a water sample through the paper filter to capture the chlorophyll/algae in the water. Photo by Grant Vander Laan

Back at the office, the samples are filtered through a tiny paper to collect the chlorophyll. The paper filters are then frozen until we drop them off for the CLMP to further process them. Two paper filters of chlorophyll are processed for each lake for better results. Parker is filtering one of the samples above through a syringe.

Actions Taken from Data Collected

At the end of the season, when the Cooperative Lakes Monitoring Program staff enters all the data into the giant database for the state, management plans for the lakes can be updated from that data. Currently, we do not have enough years of data from phosphorous, water clarity, dissolved oxygen, and chlorophyll to make assumptions of what needs to be changed at that lake. That is because several years of data collection are needed to see trends happening at our lakes. The only measurement we were able to directly act on currently is the data from the exotic aquatic plant watch. During the exotic aquatic plant watch at Twin Lake, curly-leaf pondweed (an invasive species) was found. Since its discovery, we have been treating curly-leaf pondweed near our dock at Twin Lake. Hopefully, within the next couple of years, we can gain enough data from our other measurements to create management plans for both lakes.

How to Keep Our Watershed Clean from Your Own Backyard

Though you might not live on or near Twin Lake or Lost Lake, you can still help keep the Clinton River Watershed clean. Even actions you take in your backyard can have implications on the Clinton River Watershed. Below are some actions you can take to keep our watershed clean and healthy!

At Home Actions:

  • To avoid overapplying fertilizers, eliminate fertilizers in your yard or use organic or slow-release fertilizers instead.
  • Don’t treat with pesticides or fertilizers with 15 feet of a water source (creek, river, lake).
  • Don’t pour toxic household chemicals down the drain. Take them to a hazardous waste center or drop off site like NoHaz.
  • Consider putting in a rain garden to catch and filter runoff from your roof, driveway, or sidewalks.
  • When camping, use biodegradable soaps like Dr. Bronner’s and rinse dishes away from lakes and streams.
  • Pick up dog poop in your yard so that it doesn’t run into streams/ lakes and create bacterial problems.
  • Plant native plants that require fewer pesticides and fertilizers.
  • Wash cars on the lawn or at a carwash.

In your Community Actions:

  • Encourage your state and local governments to protect wetlands and protect water quality.
  • Consider volunteering with the Clinton River Watershed Council (CRWC) on one of their weekly cleanups.
  • Participate in the Clinton Cleanup 2021 on Sept 18th with the CRWC! (see link below)

If you want to learn more about volunteering with the CRWC please look at their website here: https://www.crwc.org/events/volunteer/keeping-it-clean

If you want to learn more about the Cooperative Lakes Monitoring Program, check out their website here: https://micorps.net/lake-monitoring/

The shoreline of the eastern Twin Lake at Draper Twin Lake Park.

3 thoughts on “Taking a Dip Into the Science of Lakes

  1. Katri – Wow, that’s a lot of good info packed into one blog! But I think I understood it all. So glad you folks are monitoring our lakes so thoroughly – and that you grew up caring so much about water quality. Like Max, I appreciate the reminders on tips to use at home, too. Thanks!

  2. Great post Katri! The watershed map was fascinating and I like how you mentioned the ways to minimize contamination in our communities and homes.

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