Barb Liukkonen, Water Resources Education Coordinator, University of Minnesota Extension Service and Minnesota Sea Grant, (612) 624-9256

How much water is there in your lake? Knowing this value may prove to be useful. Maybe you want to figure out the residence time of water in your lake (see the next article). Maybe you need to determine the proper application of an aquatic herbicide (or check on your contractor’s calculations). Maybe you just want to impress your lake association members or neighbors. Whatever your reason, here is a method you can use. It does require that you refresh your arithmetic skills and round up a bathymetric map, a measuring tool, and a calculator.

A bathymetric map shows contours, or lines connecting points of equal depth, in a lake. You can get bathymetric maps for many Minnesota lakes from local sporting goods stores or the Internet (e.g., go to the Minnesota Department of Natural Resources Lake Finder Web site). You can create your own if you have a GPS unit, a depth finder, and a lot of spare time. Contour intervals on bathymetric maps are usually in 5- or 10-foot increments.

Typical bathymetric map.

A formula is used to determine the volume of your irregularly shaped lake. The formula treats your lake like a series of layers, each layer shaped like a cone with the bottom chopped off (called a “frustrum”). You need to know the height and area of each layer in order to use the formula to calculate volume. Look at the depth zones drawing, which shows a 3D view of the bathymetric map above. Area 1 (A1) is equivalent to the 0 ft contour line, or the area of the whole lake. Area 2 (A2) is equivalent to the area encompassed by the 10 ft contour line, and so on. The difference in depth between two successive layers is the height (H) of that layer (in this example, 10 feet).

Depth zones in lake.

Your first task is to calculate the surface area within each contour line to plug into the formula. You can do this in a number of ways, depending on what tools you have available.

1. Trace around the contour lines with a mechanical planimeter.
2. Use a computer program such as ArcView.
3. Cut out the contours and weigh them to determine the relative percentage of the total area made up of each successive contour in the lake. The weighing method is quite accurate, but requires a sensitive balance, such as would be available in a high school science laboratory.
4. The simplest method is to transfer your bathymetric map to graph paper and count how many squares fall within each contour line. This may reduce accuracy because you often have to estimate by half- or quarter-squares, but it works.

Consider making a table with rows for each contour interval (e.g., 0-10 feet, 10-20 feet, 20-30 feet, etc.), and columns for your measurements, surface area (in acres and/or square feet), and volume. The number of rows in your table will depend on how deep your lake is – you need a row for each contour interval. A table like this may help you manage the numbers you’re going to generate. Sample determinations are included for a few layers.

* The conversion factor you’ll need to use will depend on the scale of your map.

** See instructions below for calculating the area of the lowermost layer.

Use the formula below to calculate the volume of water in each contour band of the lake (i.e., between 0 and 10 feet deep, between 10 and 20 feet, and so on). If your map has 5-foot contour lines, follow the same procedure (0-5 feet, 5-10 feet, 10-15 feet, etc.). The formula is:

V = H/3 (Al + A2 + /(Al x A2))

V = volume of water in each contour band

H = difference in feet between two contour depths

Al = area of the lake within the outer contour

A2 = area of the lake within the inner contour

Depending on the scale of your bathymetric map, you may want to convert to acres for ease of calculation. There are 43,560 square feet in one acre. If you use acres for surface area and feet for depth, the volume you calculate will be in acre-feet. An acre-foot of water is one acre of water one foot deep, i.e., 43,560 cubic feet (~326,000 gallons).

**The calculation for the lowermost layer (in this example – 20-26 ft) uses a geometric cone formula: volume = 1/3(HxA). This formula assumes that the maximum depth of 26 feet occurs in one small area. So, in our example, the height would be 6 feet and the area would be the area of the 20 foot contour interval.

Note: If the maximum depth of 26 feet stretches over a broad area (determined by studying the bathymetric map, then encircle this area with a contour line, determine its area with a one of the methods described above, and use the frustum formula to calculate volume of the 20-26 foot zone.

This article is partially based on: Taube, C.M. 2000. Instructions for winter lake mapping. Chapter 12 in Schneider, J.C. (ed.). Manual of Fisheries Survey Methods II: With Periodic Updates. Michigan Department of Natural Resources, Fisheries Special Report 25, Ann Arbor.

Cindy Hagley, Great Lakes Environmental Quality Educator, Minnesota Sea Grant, (218) 726-8106

In the language of lakes, residence time (also called retention time) is the period required to completely replace a lake’s water with an equal volume of “new” water. If you compare a lake to a bathtub, residence time might be easier to understand. Filling a bathtub takes just a few minutes if the drain is closed. The 5 or so minutes it takes would be the bathtub’s residence time. However, if the drain is open or the faucet is only dripping, filling the tub will take longer; its residence time could be hours or possibly days. Of course, residence time also depends on how big the tub is. So, a lake’s residence time depends on 3 major factors, the rate of water inflow, the capacity of the lake to hold water (its volume), and the rate of water outflow.

Residence time can vary greatly in lakes, from a few days in many reservoirs to hundreds of years. Lakes with small volumes and high flow rates have short residence times, and lakes with large volumes and low flow rates have long residence times. For example, Lake Superior has a residence time of roughly 191 years compared to Lake George, in Uganda, with a residence time of four months.

Why do we care about a lake’s residence time? The longer a lake’s residence time, the longer it takes to refresh its waters. Pollutants tend to hang around a lot longer in lakes with longer residence times. If your lake association has worked to reduce inputs of nutrients or other contaminants into your lake, knowing your lake’s residence time will help you gauge how long it will take to see improvements in water quality. There are many other factors that impact water quality, so residence time by itself will not answer your questions, but it is an important characteristic to understand about your lake. It is necessary to know your lake’s residence time to determine annual lake budgets for water, nutrients, heat, oxygen, contaminants, and herbicides.

A lake’s residence time is calculated by dividing the lake’s volume by its average annual water outflow. Lake managers calculate outflow on an annual basis so that seasonal variation doesn’t unduly influence results. Volume (V) is usually expressed in acre-feet, and mean outflow is expressed as acre-feet/year. So the formula looks like this:

Residence time (years) = lake volume (acre-ft) / mean outflow (acre-ft/yr)

In lakes with very short residence times (i.e., a lake with a small volume and high inflow and outflow rates), algae may get flushed out of the lake so fast that they don’t accumulate. Intermediate residence times allow algae and aquatic plants plenty of time to take advantage of the nutrients that are present. In lakes with longer residence times, phosphorus coming into the lake tends to have more time and opportunity to bind to particles, either through biological activity or through chemical and physical processes. These particles settle out of the water and are deposited in the sediments, making the attached phosphorus at least temporarily unavailable to algae and other plants. So lakes with long residence times can have lower phosphorus concentrations in the water. Residence time is one of the major variables that scientists incorporate into models predicting phosphorus retention and impacts in lakes. Determining residence time for your lake is probably not a job you can take on without some expert help, but it is an important characteristic of your lake.

Sources:

• Water on the Web, Module 8, Lecture 1. www.waterontheweb.org/curricula/ws/unit_03/U3mod8_9.html
• Holdren, C., W. Jones, and J. Taggart. 2001. Managing Lakes and Reservoirs. N. Am. Lake Manage. Soc. and Terrene Inst., in coop. with Off.Water Assess.Watershed Prot. Div. U.S. Environ. Prot. Agency, Madison, WI.
• Wedepohl, R.E., D.R. Knauer, G.B. Wolbert, H. Olem, P.J. Garrison, and K. Kepford. 1990. Monitoring Lake and Reservoir Restoration. EPA 440/4-90-007. Prep. By N. Am. Lake Manage. Soc. for U.S. Environ. Prot. Agency,Washington, DC.

Cindy Hagley, Great Lakes Environmental Quality Educator, Univ. of Minnesota Sea Grant, 218-726-8713

Empire Bluff at Sleeping Bear Dunes National Lakeshore, MI. Image credit: Travel Michigan

Are you old enough to remember the old commercial jingle, “From the land of sky blue waters….?” When we think about a beautiful lake scene, we usually picture blue water surrounded by green trees, but how many of us know what determines the color of lake water?

The reasons a lake is a particular color are complex. In fact, lake colors can vary widely, ranging from nearly colorless, to yellowish or reddish or brownish or greenish or bluish! The same lake can even range in colors over different seasons, weather cycles, or types of human activity in the watershed.

So what are some of the factors that determine the color of lake water? Pure water has a pale blue color, caused by selective absorption at the red end of the visible light spectrum, but no “real-live” lake is made up of pure water. The color we perceive when we look at lake water is called apparent color. Apparent color is determined by many factors, including how much light is being reflected or absorbed by materials suspended or dissolved in the water, the color of the lake bottom, the depth of the lake, reflections from the sky or surrounding vegetation, and aquatic plant presence or absence. If you collect a sample of lake water in mid-summer and hold it up to the light, you will probably see things floating in it, including algae, dead plant and animal matter, possibly some clay, and maybe even some little animals, or zooplankton. These are all examples of suspended substances that can influence apparent color of a lake. For example, a nutrient-rich lake with high algal densities might appear greenish when you look into it.

Apparent color is hard to quantify or compare among lakes because of all the factors that can influence it, so scientists prefer to measure true color. To measure true color, scientists filter out all the suspended materials. This leaves them with a water sample containing only dissolved substances. Dissolved substances include metallic ions from rocks and soils (for example, iron and manganese ions) as well as organic acids from decomposing vegetation. Do you ever brew and drink tea? When you soak tea leaves, the organic acids and tannins from the tea leaves stain the water the lovely reddishbrown color we associate with a great cup of tea. The very same process brings much of the true color to lakes.

After filtering the water, the resulting true color is compared to a standard color scale (in the U.S. we usually use the platinum-cobalt color scale). This color scale allows us to compare among lakes or in one lake over time. Platinum-cobalt values of less than 20 indicate clear water, while values from 20 to over 100 indicate a highly colored lake. Lakes that are highly colored have often been “stained” by water flowing in from wetlands or forests.

Why do scientists care about lake color? Again the complete answer is complicated, but probably the most important reason is that the very same dissolved and suspended substances that give lakes their color do so by changing the way light is refracted, reflected, and absorbed. Not only is light essential for the growth of plants, including algae, but light energy and the heat it provides are also critical for plants and animals. Anything that reduces the depth of light penetration has impacts on the biological condition of the lake. Many fish and diving birds, such as loons, rely on water clarity to find their prey. In fact, if other things are equal, a lake with a higher true color value will probably have less biological activity than a similar lake with a lower true color value.

Next time you find yourself humming a song about Minnesota’s sky blue waters, remember – it is not quite that simple!

References

• Florida LAKEWATCH. 2004. A Beginner’s Guide to Water Management – Color. 1st Edition. http://lakewatch.ifas.ufl.edu/LWcirc.html.
• Minnesota Pollution Control Agency. 1999. Minnesota Lake Water Quality Assessment Data: 2000. http:// www.pca.state.mn.us/water/pubs/lwqar.pdf.

Some of the most important causes of differences among lakes include the lake’s size and shape, what activities occur in the lands that drain into it, what ecoregion the lake is located in, and when and how the lake basin was formed. These factors, acting in various combinations, have created the multitude of lake types found in Minnesota today.

Minnesota lies at a crossroads of ecological land types, with widespread differences in soils, underlying geology, and plant and animal communities. These differences are classified into ecoregions, or broad areas that share similar land uses, soils, topography, and vegetation. Minnesota is classified into seven ecoregions. Ninety-eight percent of Minnesota’s lakes occur in just four of them: Northern Lakes and Forests, North Central Hardwood Forests, Western Corn Belt Plains, and Northern Glaciated Plains.

Western Cornbelt plains.

Lakes within ecoregions often have similar physical characteristics, water chemistry, and biological communities. The number, appearance, and condition of lakes vary among ecoregions because of glacial history, geology, soil type, land use, and climate. You can learn more about this subject at the MN Shoreland Management Resource Guide Web site or from the MN Pollution Control Agency PDF report.

Excerpted from MN Shoreland Management Resource Guide Web Site – Quick and Easy Answers – Ecoregion Influences on Lakes.

Barb Liukkonen, Water Resources Center, 612-625-9256

Those three terms are often used interchangeably, which is incorrect. They don’t mean the same thing, although they are closely related. Here’s a quick guide to understanding what these parameters are telling you about water clarity.

Transparency is a measure of how well light passes through the water column. Transparency is usually measured with a Secchi disk (for lakes) or transparency tube (for streams), although it can be measured in the field with a light meter. Secchi disk readings are probably the most commonly collected water quality data across the U.S. Transparency measurements are typically made in situ (on site) and can be affected by suspended sediment, algae, and water color (i.e., humic acids that stain the water red or brown).

Turbidity is a measure of the how much light is scattered by particles in the water. It is reported in NTUs (Nephelometric Turbidity Units) and is measured with a nephelometer, which may cost several hundred dollars. Turbidity measurements can be made in situ with a meter or back in the lab. Algae blooms or suspended sediment can increase turbidity because light is scattered by particles in the water, whether those particles are sediment or algae.

Total Suspended Solids (TSS) is a direct measurement of the particles suspended in the water - by weight. That means you must collect a sample and take it back to the lab where the water is filtered and dried in an oven, before being weighed. Sediment weighs more than algae, so TSS is a more accurate measurement of how much sediment is in the water, whereas turbidity is affected equally by sediment or algae.

If you collect samples for turbidity or TSS, be sure to shake the container thoroughly before taking a measurement, so whatever has settled out is re-suspended. Neither TSS or turbidity measurements are affected by colored water.

TSS and turbidity are inversely correlated with transparency. That means that as turbidity or TSS increases, transparency decreases (more stuff in the water translates to reduced light penetration).

A secchi disk is used to measure water clarity.

Thanks to committed volunteers we’re building an extensive database for transparency across Minnesota. Those data can be used to establish long-term trends or to identify significant changes in water clarity. Most volunteers will continue to gather important transparency data with their trusty Secchi disk, but if you want to know more about the cause of reduced transparency, you might want to sample for turbidity or TSS.

Chip Welling; Coordinator, Eurasian Watermilfoil Program; Minnesota Department of Natural Resources; 500 Lafayette Road; Saint Paul, MN 55155-4025; 651-297-8021.

Eurasian watermilfoil, or simply, milfoil, is a non-native, submersed aquatic plant that may cause problems in lakes when it becomes abundant. In the January-February 2004 issue of this newsletter, I provided some background on the use of herbicides to control milfoil. This issue will focus on the use of fluridone for milfoil control.

Fluridone is the active ingredient in Sonar or Avast! herbicides.

The principal difference between fluridone and other herbicides is that fluridone cannot be used effectively for spot-treatments, but must be applied to whole bays or lakes. The DNR has been making whole-lake treatments with fluridone since the early 1990s and monitoring their effects. The purpose of these studies was to determine whether this herbicide can be used to selectively control milfoil. Treatment in 1994 at a target rate of 10 ppb fluridone reduced native vegetation lake-wide, and was followed by a decrease in clarity of the water in one of two treated lakes in the Twin Cites area. This damage was considered to be significant. As a result, the DNR decided to allow use of fluridone only in lakes that have high potential to become a source of spread of milfoil in an area of Minnesota without milfoil.

Such a situation arose in 1999 when milfoil was discovered in McKinney and Ice Lakes in Grand Rapids. At the time, no other lakes in the area were known to have the exotic. Consequently, the DNR treated both lakes with fluridone in an attempt to limit further spread in this part of Minnesota.

In 2000, new information from Michigan suggested that application of fluridone at low rates of about five ppb might provide more selective control than had previously been observed in Minnesota. In an attempt to reproduce the Michigan results, the DNR treated three Minnesota lakes at about five ppb in 2002. Treatment reduced the frequency of Eurasian watermilfoil to zero, but, unfortunately, also reduced the biomass of native submersed plants by an average of 94 percent. Following treatment with fluridone, water clarity decreased in two of the three treated lakes. Unfortunately, this damage appears to outweigh the benefits of controlling milfoil.

The lakes treated in 2002 had low water clarities of 2.5 to 5.5 feet. Two of the lakes had communities of submersed plants dominated by milfoil and coontail with few native species. By comparison, some of the treated Michigan lakes as well as one other lake in the Twin Cities, Lac Lavon, had higher water clarity and more native plants before treatment.

Following treatment of Lac Lavon, the distribution of milfoil decreased dramatically, and native submersed species increased. Four years after treatment, the milfoil had returned to pre-treatment levels of abundance and the native species had decreased. After another treatment, the milfoil decreased again and the native plants began to increase. This result means that long-term control of milfoil will require repeated whole-lake treatments with fluridone, as is already the practice in Michigan.

As the DNR’s evaluation of fluridone continues, we expect to further investigate the relationship between lake condition, specifically water clarity and composition of the vegetation, versus the effects of whole-lake treatment with fluridone.

What to look for when idenitfying Eurasian watermilfoil.

Chip Welling; Coordinator, Eurasian Watermilfoil Program; Minnesota Department of Natural Resources; 500 Lafayette Road; Saint Paul, MN 55155-4025; 651-297-8021Many Minnesotans are familiar with Eurasian watermilfoil, or simply, milfoil. Milfoil is an invasive and non-native, submersed aquatic plant that causes problems when it produces mats of vegetation on the water’s surface. These mats, which are more extensive than those produced by native plants, can interfere with recreation and access to open water.

Controlling milfoil in lakes where it has been introduced can be a big challenge. Our experience over the past ten years with this plant is that permanent eradication or elimination of the non-native plant from a lake is not a realistic goal. A realistic goal is to manage problems caused by milfoil.

Physical methods such as cutting and harvesting can be effective in controlling milfoil. The use of herbicides is believed by many people to be the easiest, least expensive, and most effective strategy. One product that has generated much interest among Minnesotans interested in control of milfoil is fluridone, which is the active ingredient in Sonar™ or Avast!™ herbicides.

My purpose in writing this article is to describe the background within which the Department of Natural Resources (DNR) is evaluating the potential use of fluridone in Minnesota.

There are two categories of herbicides allowed for control of submersed aquatic plants: contact herbicides or systemic herbicides. Generally, contact herbicides act more quickly than do systemic herbicides.

Contact herbicides only affect the plant parts contacted, usually just leaves and stems. As a result, control produced by contact herbicides often is of shorter duration than control produced by systemic herbicides. The latter can be absorbed by the plant and moved within the plant. This means that systemic herbicides can control roots and other underground plant parts, as well as stems and leaves. Generally, control of submersed aquatic plants in Minnesota is repeated annually.

Drawing of watermilfoil.

It is important to remember that any use of herbicides in Minnesota lakes requires a permit from the DNR. In Minnesota, herbicides are usually applied as ‘spot-treatments’ to control submersed plants in limited areas adjacent to privately-owned shoreline. These areas may extend along 50 to 100 feet of each property’s shoreline and 100 to 150 feet lake-ward. On a whole-lake basis, the cumulative total of spottreatments is not allowed to exceed 15 percent of the littoral zone, the area that is 15 feet deep or less. This limit is necessary because submersed plants, even milfoil, can provide habitat for fish and wildlife, protect water quality, and limit erosion of shorelines. This limit allows sufficient control for access and recreation on most lakes and a variance can be issued to allow larger treatments, if necessary.

With this background in mind, let’s consider fluridone, a systemic herbicide. The principal difference between fluridone and other herbicides is that fluridone cannot be used effectively for spot-treatments, but must be applied to whole bays or lakes. The principal reason for considering fluridone is that milfoil is highly susceptible to this herbicide, which can provide lake-wide and multi-year control of this non-native plant.

At present, the DNR does not allow operational whole-lake treatment with fluridone to control milfoil due to the lack of conclusive information on the selectivity of fluridone. If this herbicide could remove only milfoil and allow native plants to survive or, better yet, increase, then the DNR would have fewer reservations about use of this product. The purpose of the DNR’s continuing evaluation of fluridone is to increase our understanding of the effects of this product on native plants, as well as possible indirect effects on water quality and perhaps other aspects of lake ecosystems. The overall challenge for users of Minnesota’s lakes and the DNR is to determine whether the benefit of controlling milfoil by whole-lake treatment with fluridone is worth the risk of possible harm to lakes. In a following article, I will provide an update on the DNR’s continuing evaluation of this herbicide.

Curly-leaf pondweed has been identified in over 500 water bodies in Minnesota. This non-native aquatic plant is often characterized as an invasive nuisance species and during the past few years many shoreland property owners have experienced increasing problems caused by its growth and spread. Requests for information and assistance with managing curly-leaf pondweed infestations have increased over the past two years. In response, the University of Minnesota Extension Service Shoreland Education Program recently offered three workshops to help property owners, local units of government, and lake association leaders better understand how to manage this nasty invader.

Workshops in Big Lake, Nisswa, and Richfield attracted nearly 150 participants who learned about the value of preserving native aquatic plants, the life cycle and characteristics of curly-leaf pondweed, various management methods (cutting, harvesting, chemical and physical options), recent research, and the permitting process for curly-leaf pondweed control. Speakers included representatives from the University of Minnesota Extension Service, Minnesota Sea Grant, Minnesota DNR, local governments, Minnesota Lakes Association, and private consultants and lake management professionals. Lake association leaders also shared their experiences in managing curly-leaf pondweed. The take-home messages for attendees: Preventing the introduction of curly-leaf pondweed into a water body is the only real “control.” There is, to date, no “silver bullet” method of eradicating curly-leaf pondweed once it has invaded a water body. Several factors need to be considered (with the help of natural resource professionals) before selecting an appropriate management method for a lake. Management of curly-leaf pondweed is costly, ongoing, requires a DNR permit, and may alter the ecology of the lake.

These workshops were co-sponsored by the Water Resources Center, Sea Grant Program, Minnesota Extension Service, Minnesota Lakes Association, and the Initiative Foundation.

Included in this issue of From Shore to Shore is a curly-leaf pondweed identification handout for you to use, make copies, and share.

These terms may be new to many Minnesotans, but they are likely to become common vocabulary among property owners and professionals discussing options for controlling erosion along shorelines – thanks to a new brochure, Shoreland Erosion Control for Property Owners, that describes appropriate use and detailed installation of these materials.

Erosion is common along many of our lakes, rivers, and streams. Although erosion is a natural part of river and stream development as watercourses track across a flood plain, the increased incidence and severity of shoreline erosion along waterways and around lakes is often related to human land and water use. Described in this brochure are simple and relatively low- or no-cost bioengineering materials that property owners can install themselves along shorelines experiencing mild to moderate erosion (for severe erosion problems, owners should consult with their local Soil and Water Conservation District).

Shores with a slight to moderate erosion can benefit from one or more of the methods described in this fact sheet.

“Bioengineering” refers the use of living plants materials and/or non-living plant products to create a protective “soft” armor against erosive forces. When installed properly, live stakes, control.pdf willow wattles and/or coconut fiber logs perform several functions at the waters edge. They protect erosion faces from direct wave and ice action and create a more gradual slope over which waves and ice can flow. They also form a protective layer of vegetation that helps hold soil in place and provides wildlife habitat.

Coconut fiber logs.

“Shoreland first aid” is an important first step in dealing with immediate erosion problems. However, to be most effective, potential causes of erosion should be identified and addressed with additional preventative measures. A few common causes of erosion at should be considered are: Was the natural wave break of aquatic plants removed? Were the deep-rooted wetland plants replaced with shallow-rooted turf or damaged by increased foot or vehicle traffic? Has run-off increased due to impervious surfaces or been channelized via paths, ditches, pipes? Has wave action from boat traffic increased? Is there an unnatural change in water level? Are muskrats burrowing into the shore? If these conditions exist along your shoreland property, additional aquatic and wetland plants may need to be installed, traffic and run-off may need to be redirected, or “no wake zones” may need to be established.

The brochure, Shoreland Erosion Control for Property Owners, can be viewed and downloaded as a PDF file from the Shoreland Management web site.

People are attracted to northern Minnesota lakes and rivers having good water quality and relatively pristine environments. But just how much are buyers of lakeshore property willing to pay for water quality and a natural environment? How much will property prices change with a change in water quality? What market trends do we see in lakeshore property within the Upper Mississippi River watershed?

Mississippi watershed lake counties.

The Mississippi Headwaters Board and Bemidji State University joined forces to answer these questions for lakes in the Upper Mississippi River Watershed—the first indepth study of this kind in Minnesota.

According to this study of 1205 properties on thirty seven lakes in the Mississippi River headwaters area , “property prices paid are higher on lakes having higher water quality. In other words, buyers of lakeshore properties prefer and will pay more for properties on lakes with better water quality. Therefore, sustaining and/or improving lake water quality will protect and/or improve lakeshore property values.”

Should the water clarity of a lake increase one meter, one would expect a property price increase of between $1.08 (Balsam Lake) and $423.58 (Leech Lake) per frontage foot! “On the other hand, if water quality is degraded, lower property values will result, which in turn will increase the demand and development pressures on remaining lakes with the better water quality and ultimately lowering their water quality as well.”

In the Aitkin area greater prices are paid for shoreland properties that are more ecologically healthy – a preference that “will promote and establish sustainable investments by owners of Minnesota’s riparian properties.” However, in the Brainerd, Walker and Bemidji areas, “buyers of lakeshore properties prefer and pay more for the more developed and urbanized properties. This tendency seems to reveal that buyers prefer a condition that has and can contribute to degrading lake water quality – a contradiction of their preference for locating on lakes with higher water quality. The value of providing information to lakeshore property buyers and owners (in these areas) to understand this contradiction – revise riparian thinking and ultimately land management – is clearly evidenced here if water quality is to be protected.”

References:

The final report (Krysel, C. et al. 2003. Lakeshore Property Values and Water Quality: evidence from property sales in the Mississippi Headwaters Region) from which the map and information for this article were adapted can be viewed and downloaded from the Bemidji State web site.