Minnetonka’s topography is full of knolls and wetlands because 15–20,000 years ago this area was at the edge of a glacier. As the glacier melted, it deposited piles of dirt and blocks of ice that left depressions in the landscape.
Early settlers in Minnesota and elsewhere found wetlands to be a barrier to travel, farming, and building cities. They drained and filled wetlands when they had to, although often they just worked around them. However, the ability to destroy wetlands accelerated in the early 20th century with the invention of better equipment for drainage and earth moving. At that time wetlands were regarded as wastelands that bred disease and prevented productive use of the land; thus, their destruction was supported by governments at all levels. Hunters were among the few who valued them.
As wetlands disappeared, it became apparent that they had been performing important functions. They provide habitat for waterfowl and other wildlife, store water to prevent flooding, and recharge groundwater supplies. Filling wetlands with trash, which had been a common practice at the time, turned out to be a bad idea because it resulted in water pollution and unstable building sites on top of the dumps. Slowly people came to see wetlands as an amenity, rather than as “just a swamp.” Between the 1970s and the 1990s, governments began to protect wetlands.
Minnetonka was spared much of the wetland destruction that went on in the heavily agricultural areas and the central cities. Our wetlands were able to hang on until we could really appreciate them! Now they are a major component of the open space in the city.
- What is a wetland?
- Wetlands are shallow depressions, not deeper than six and a half feet, which generally lie in the lowest part of the surrounding landscape. There are eight different types of wetlands in the state, which generally have three things in common. They have vegetation that is adapted to growing in wet environments, like rushes, sedges, wildflowers, and certain trees and shrubs. They have hydric soils or those soils that are normally saturated or wet. They have water at or near the soil surface.
- Could one of these be on your property?
- Some wetlands look like grassy, wild areas, wet in the spring that are dry in summer, while others may be a woodland forest where the soil feels a little soft or spongy when you walk on it. Wetlands can also have areas of open water with a fringe of wetland vegetation like cattails and rushes. The following photos illustrate some examples of wetlands.
- Photos courtesy of Applied Ecological Services Inc.
- Should you care about wetlands?
When you think of a wetland you may think of a swampy, mucky, mosquito-filled, wet area. Although some of these characteristics may be true, wetlands are much more then that. Wetlands provide us with many benefits. They are a valuable part of our landscape. If you have a wetland on your property you will want to be aware of it so you can offer it the protection it deserves. After all, wetlands protect us.
Wetlands protect our drinking water by filtering nutrients and pollutants before they seep into the groundwater. They protect our ability to swim in lakes and canoe the Minnehaha Creek because they filter contaminants and help absorb excess nutrients that are responsible for algae blooms. They protect our homes and businesses from flooding by acting like a sponge and absorbing excess amounts of water during spring snow melt and heavy rains. They allow us to experience wildlife right in our own back yard or neighborhood by providing the habitat for amphibians, reptiles, ducks and other migratory bird life. Wetlands also offer us a place to experience peace and quiet in this fast paced world we live in.
- How do I know where the wetland boundary is?
- It is important to know where the wetland boundary is in order to minimize any disturbance to these valuable resources. Remember that the wetland boundary doesn’t end where the surface water does. The boundary extends beyond this point. In addition, wetlands may include seeps or swales that project into the surrounding land. It also is possible for a wetland boundary to change over the years. In order to define a wetland boundary, the wetland must be delineated by a professional consulting firm that will use the plants, soils, and hydrology present to make a determination.
- What are we doing to protect our wetlands?
Wetlands are protected by the federal Clean Water Act, the state Wetland Conservation Act, by local watershed districts, and by city ordinance. The city enacted its first wetland ordinance in 1974 and it has been updated several times to continue to provide wetland protection. One of the most recent updates requires wetland buffers on all new developments.
Detailed information about the city’s wetlands, creeks, ponds, and lakes is contained in the City’s Water Resources Management Plan. This tool assists staff in identifying our higher quality wetlands so that they can be further protected and potentially restored. Almost 500 wetlands have been numbered, categorized, and zoned as wetlands. However, there likely are several smaller ones that have not been identified yet. The city also incorporates innovative storm water techniques like bioretention and infiltration basins to manage storm water. These techniques filter sediment and pollutants, and absorb storm water, which minimizes impacts to wetlands.
It is important to first check with the city before undertaking any work near or adjacent to a wetland. The city of Minnetonka has certain setback requirements for new construction and retaining walls from the wetland boundary. Grading, filling, or constructing fences within a wetland is not permitted. Also, you may not remove live vegetation from within a wetland.
- What can I do to protect our wetlands?
Be a good steward. Implement the following practices to help improve the quality of these fragile ecosystems.
- Adopt your neighborhood storm drain. Storm drains are directly linked to your neighborhood wetland. Remove the litter, and debris that collects before it can be washed into the wetland.
- Use environmentally sound lawn care practices. Keep grass clippings, leaves, and fertilizer out of the street and wetland.
- Pick up after your pet and properly dispose of it. Pet waste is a source of excess nutrients and bacteria.
- Direct gutter downspouts onto the lawn or garden.
- Wash your car on the lawn. This will prevent the chemicals and nutrients found in detergents from entering our wetlands.
- Properly dispose of oil, solvents, paints, and pesticides. Do not pour these onto the ground or into the storm drain.
- If you are planning a remodeling or landscaping project, keep the sediment out of the street. This soil is harmful to our wetlands.
- Avoid disturbing wetlands and keep a natural vegetative buffer. Do not mow to the wetland edge.
- Develop an appreciation for wetlands. On a warm spring evening listen for the frog calls that make the neighborhood wetland alive with sound. Watch the dragonflies and damselflies display their abilities of flight. Watch the local egret of great blue heron land and stalk the crayfish and frogs. Catch (and release) tadpoles with your kids and rekindle your youthful spirit.
These practices will help improve the quality of all of our water resources, including our lakes and creeks. For more information about wetlands contact the Minnetonka Natural Resource Division at 952.988.8422.
- US Army Corp of Engineers – St. Paul District
- Minnesota Department of Natural Resources
- Minnehaha Creek Watershed District
- Basset Creek Watershed District
- Nine Mile Creek Watershed District
- Riley Purgatory Bluff Creek Watershed District
- Minnesota Association of Watershed Districts
- Minnesota Board of Water and Soil Resources
- University of Minnesota
- US Environmental Protection Agency
- Wetland Plants and Plant Communities of Minnesota and Wisconsin—Northern Prairie Wildlife Research Center (USGS)
- Biological Monitoring of Wetlands—Minnesota Pollution Control Agency
- National Wetlands Inventory — US Fish & Wildlife Service