Water Quality and Robots: Educating Minnesota Youth�

Depts. Of Computer Science and Engineering; Soil, Water and Climate, and Extension's Center for Youth Development at the University of Minnesota;

and High Tech Kids

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This material is supported by the Environmental and Natural Resources Trust Fund (ENRTF) of the State of Minnesota.

Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the ENRTF.

Acknowledgement

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Minnesota Lake Environmental Themes�

Module 2.1: Importance of Lakes, Fun Facts About Lakes, and How Lakes Vary by Ecoregion

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Minnesota Lake Environmental Themes

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• Minnesota Lake Environmental Themes Module LET2.1

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• Objectives:

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1) Foster understanding of lake ecoregions & water quality

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2) Teach students the importance of maintaining healthy lakes in Minnesota

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Minnesota Lakes

Discussion:

• What is a lake?

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Minnesota Lakes

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• What is a lake?
• Lakes are large fixed bodies of water surrounded by land
• They do not flow quickly like rivers
• Lakes are larger than ponds. They must be larger than 10 acres to be called a lake.
• Lakes are smaller than oceans

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ACTIVITY #1: �Why Are Minnesota Lakes Important?

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Why are Lakes Important?

• Lakes are important to Minnesota’s plants, animals and humans
• They provide habitat for aquatic vegetation which shelters fish
• They provide food and water for wild animals and migratory waterfowl
• They provide water for drinking, irrigation, municipalities and industries

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Why are Lakes Important?

• Lakes play an important role in Minnesota’s identity and culture
• Lakes are respected by native peoples because they provide spiritual inspiration, fish and wild rice, and a way to travel by boat from one location to another
• People like to visit lakes to see the beautiful scenery and wildlife, relax and have fun by swimming, fishing, boating, hiking, skating and skiing
• Minnesotans are proud of their abundant and beautiful lakes

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Why are Lakes Important?

• Lakes play an important role in Minnesota’s economy
• Tourists spend money at airlines, hotels, and restaurants when they visit Minnesota lakes
• Lakeshore property is highly valued, especially on lakes with natural beauty and clean water

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Minnesota: Land of 10,000 Lakes?

• Minnesota’s nickname is “Land of 10,000 Lakes”
• Is this accurate?
• How many of you think Minnesota has fewer than 10,000 lakes?
• How many of you think Minnesota has more than 10,000 lakes?
• How many don’t know?

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Minnesota: Land of 10,000 Lakes?

Minnesota Department of Natural Resources (DNR) and the University of Minnesota SeaGrant counted how many lakes (greater than 10 acres in area) there are in Minnesota

• The answer is 14,380 lakes
• Only the state of Alaska has more lakes than Minnesota

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Fun Facts About Minnesota Lakes

• Minnesota lakes vary in area
• Very small lakes (10 to 1,000 acres) are abundant
• Moderate lakes (10,000 to 100,000 acres) are rare

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• What is a percent?
• It’s the number of lakes in each size class (acres) divided by the total number of lakes, which is then multiplied by 100
• For example, if there are 9 moderate size lakes out of a total of 100 lakes, the percent of moderate size lakes is (9/100)*100 = 9%

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Use this bar graph to complete Activity #2

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Activity #2 : What is a Percent?

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• Percent means one part in a hundred

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Fun Facts About Minnesota Lakes

• Minnesota has 34,248 miles of lake shoreline distance (the circumference of the earth is 24,901 miles!)
• Very small lakes (10 to 100 acres) have 40% of Minnesota’s lake shoreline distance
• Lakes larger than 1,000 acres have 20% of Minnesota’s lake shoreline distance

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• What is shoreline distance of a lake?
• It’s the length of the distance around the lake (circumference)
• For example, if a lake were circular, with a radius (r) of 1 mile (diameter of 2 miles), the circumference would be 2∏r = 2*3.14*1 = 6.28 miles

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Activity #3: �Fun Facts About Minnesota Lakes

• Use the Activity 3 chart to rank the following ten Minnesota lakes in order from largest to smallest. What’s your guess?
• Kabetogama – St. Louis County
• Lake of the Woods (MN part) – Lake of the Woods
• Lake Superior (MN part) – Cook, Lake and St. Louis Counties
• Leech – Cass County
• Mille Lacs – Mille Lacs and Aitken Counties
• Rainy (MN part) – St. Louis County
• Red (Lower) – Beltrami County
• Red (Upper) – Beltrami County
• Vermilion (East) – St. Louis County
• Winnibigoshish –Cass County

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Answer to Activity #3: �Fun Facts About Minnesota Lakes

• Answer: What are the ten largest lakes in Minnesota?

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Lake Superior (MN part)

Lake of the Woods (MN part)

Red (Lower)

Mille Lacs

Red (Upper)

Leech

Rainy (MN part)

Winnibigoshish

Vermilion (East)

Kabetogama

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Activity #4: �Fun Facts About Minnesota Lakes

• Use the chart for Activity #4 to estimate the maximum depths of Minnesota’s ten largest lakes

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Lake Superior (MN part)

Lake of the Woods (MN part)

Red (Lower)

Mille Lacs

Red (Upper)

Leech

Rainy (MN part)

Winnibigoshish

Vermilion (East)

Kabetogama

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Fun Facts About Minnesota Lakes

• If all the water in Lake Superior were spread out one foot deep, how much area would the water cover?
• Minnesota
• Midwestern US
• United States
• North America
• North and South America

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• Hint: Lake Superior has an area of 31,700 sq. miles and an average depth of 483 feet

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Example Calculation

A lake has an area of 10 sq. miles and an average depth of 100 feet. How much area would the lake volume cover if spread out 1 ft deep?

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Step 1: Convert depth in feet to miles

• X miles = 100 feet/(5,280 feet/mile)
• X = 0.019 miles

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Step 2: Convert 1 ft to miles

• Y miles = 1 ft/(5,280 ft/mi)
• Y = 0.00019 miles

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Step 3: Calculate volume of lake

• Volume = depth x area
• Volume = 0.019 miles x 10 sq. miles
• Volume = 0.19 cubic miles

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Step 4: Calculate area covered if lake water volume is spread out 1 ft deep

• Z (sq. miles) = Lake volume/spreading depth
• Z sq. miles = 0.19 cubic mi/(0.00019 mi)
• Answer Z = 1000 sq. miles

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Minnesota Lake Health and Ecoregions

• Lake health in Minnesota varies according to factors such as:
• Lake depth
• Climate
• Geology and topography
• Size of watershed draining to lake
• Soil types in watershed
• Land cover in watershed
• Water quality of lake
• These factors are summarized using seven distinct Minnesota Ecoregions

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Activity #5: Minnesota Ecoregions

• Use the slide titled “Minnesota Lake Health and Ecoregions.” Use a pencil to sketch the boundaries of each ecoregion on the map. Color each ecoregion a different color and then create a Map Key.

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Draw Ecoregion boundaries on county map in Activity #5

Directions

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Minnesota Lakes and Ecoregions

• Water quality of Minnesota lakes is evaluated and monitored regularly by the Minnesota Pollution Control Agency (MPCA) and the Dept. Natural Resources (DNR)

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• A majority of lakes are located in four ecoregions
• Northern Lakes and Forests
• North Central Hardwood Forests
• Northern Glaciated Plains
• Western Corn Belt Plains

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• Discussion Question: Why aren’t there many lakes in the other ecoregions?

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Minnesota Lakes and Ecoregions

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• Answer: Why aren’t there many lakes in the other ecoregions?
• Red River Valley (too flat)
• Northern Minnesota Wetlands (many areas of standing water, too small to be classified as lakes)
• Driftless Area (many steep rivers, limestone geology which drains water quickly)

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Minnesota Lakes and Ecoregions

• A subset known as “sentinel” lakes are intensively monitored by DNR for water quality, plants, invertebrates and fish to identify stresses caused by climate change, land use patterns, shoreline development and invasive species

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• Example sentinel lakes in four ecoregions
• Northern Lakes and Forests: Ten Mile Lake
• North Central Hardwood Forests: Pearl Lake
• Northern Glaciated Plains: Lake Shaokotan
• Western Corn Belt Plains: St. Olaf Lake

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Northern Glaciated

Plains

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Northern Lakes and Forests Ecoregion

• This ecoregion has many small lakes, which tend to be relatively deep and have high water clarity
• Small size, deep lakes mixed with many wetlands that filter out pollutants
• Cold winters and moderate summers with moderate rainfall
• Located in northeastern Minnesota
• Rocky, shallow sandy soils with low nutrients
• Land cover in watershed is mostly forest (spruce, pine, aspen, birch)
• Very low concentrations of phosphorus
• A sentinel lake in the NLF Ecoregion:
• Ten Mile Lake near Hackensack in Cass Co.

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Summarize these lake characteristics using the chart for Activity #6

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North Central Hardwood Forests Ecoregion

• This ecoregion has many lakes, which tend to be relatively deep and have high water clarity
• Moderate size, deep lakes
• Cool winters and warm summers with moderate rainfall
• Located in central Minnesota
• Shallow sandy and silty soils
• Land cover in watershed is a mix of cultivated land, pasture and dairies, and hardwood forests (oak, maple, basswood)
• Low concentrations of phosphorus
• A sentinel lake in the NCHF Ecoregion:
• Pearl Lake near Cold Springs in Stearns Co.

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Summarize these lake characteristics using the chart for Activity #6

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Northern Glaciated Plains Ecoregion

• This ecoregion has a moderate number of lakes, which tend to be shallow and have moderate water clarity
• Moderate size, shallow lakes
• Cold winters and hot summers with low precipitation
• Located in western Minnesota
• Silty clay soils with moderate nutrients
• Land cover in watershed is mostly row crop agriculture on a landscape that was originally prairie grass
• Moderate concentrations of phosphorus
• A sentinel lake in the NGP Ecoregion:
• Lake Shaokatan near Ivanhoe in Lincoln Co.

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Summarize these lake characteristics using the chart for Activity #6

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Western Corn Belt Plains Ecoregion

• This ecoregion has few lakes, which tend to be shallow and have low water clarity
• Moderate size, shallow lakes
• Cold winters and hot summers with moderate to high precipitation
• Located in southern Minnesota
• Silty clay soils with high nutrients
• Land cover in watershed is mostly row crop agriculture
• High concentrations of phosphorus
• A sentinel lake in the WCBP Ecoregion:
• St. Olaf Lake near Mankato in Waseca Co.

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Summarize these lake characteristics using the chart for Activity #6

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Minnesota DNR LakeFinder Information

• The Minnesota Dept of Natural Resources LakeFinder summarizes:
• Lake location
• Lake area and depth
• Lake shoreline length
• Fish species present
• Lake aquatic plant surveys
• Water quality monitoring data

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• Link to University of Minnesota Lake Browser (Lake Maps) for lake clarity summaries (turn on legend)

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• https://www.dnr.state.mn.us/lakefind/index.html

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Activity #7: Minnesota DNR LakeFinder

• Use the LakeFinder to compare sentinel lakes in different Ecoregions:
• Ten Mile Lake near Hackensack in Cass Co.
• Pearl Lake near Cold Springs in Stearns Co.
• Lake Shaokatan near Ivanhoe in Lincoln Co.
• St. Olaf Lake near Mankato in Waseca Co.

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• How do these lakes differ in depth, area, diversity of fish and lake clarity?

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• See the accompanying video tutorial on DNR LakeFinder

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(After finding lake in LakeFinder, summarize depth, area and fish species, then open Water Clarity link and click on the lake to see water clarity in meters)

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https://www.dnr.state.mn.us/lakefind/index.html

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