What is the difference between a wetland and a pond?

Minnetonka Mike, the city of Minnetonka’s online request system, is always standing by to help you with any questions, comments or concerns you have about your city. Mike wanted to know more about Minnetonka’s water resources, so he sat down for a chat with Aaron Schwartz, city of Minnetonka natural resource specialist.

MM: Minnetonka’s natural environment includes many water resources, from lakes to creeks to ponds to more than 400 wetlands. I know what a lake and creek look like, but what’s the difference between a pond and a wetland?
AS: Most wetlands are naturally occurring and can be identified by the presence of plants such as cattails that are adapted to wet areas, and by the appearance of water that is either on or just below the surface for at least part of the year. In addition, wetlands soils usually differ in color and content from the surrounding upland soils. A pond may refer to any small body of water, including a drainage pond, wetland, or even a natural depression that floods during a rainstorm.
MM: What’s the purpose of a drainage pond?
AS: Drainage, or storm water, ponds are man-made and are designed to collect storm water from streets, roofs, parking lots and other surfaces. Drainage ponds protect wetlands by pre-treating storm water and reduce flooding and erosion by capturing heavy rainfall and releasing it slowly into adjacent waterways. They also allow some of the sediment and nutrients in the water to settle out before being released into the nearest wetland, lake, or creek. Because drainage ponds usually hold water for at least part of the year, over time they may develop the appearance of a wetland.
MM: I bet if you see a culvert or drain pipe, or if a wetland looks manmade, that means it’s a drainage pond!
AS: Not necessarily. Culverts, outlet pipes, or other drainage structures may be present in either a drainage pond or a wetland. In addition, wetlands may have been partially excavated in the past in order to retain additional storm water or altered as the result of development and may appear similar to a drainage pond.
: So, a pond may be a wetland, and a wetland might be a drainage pond or a pond, and a drainage pond might look like a pond or a wetland. How is a resident supposed to know for sure what type of water resource they have on their property?
AS: You can start by researching the history of the pond before development occurred, or contact the city and we’ll help you figure it out.
: Since wetlands are an important part of Minnetonka’s natural environment, how can residents help protect these resources?
AS: Since wetlands and drainage ponds may receive water runoff directly from roadways and storm sewers, it’s important to keep paved surfaces free of pet and yard waste, fertilizer, and sediment that may wash into the storm drain or waterway during the next rainfall or snow melt. In addition, leaving a strip of native vegetation or unmowed grass along the pond edge will help filter sediment and nutrients from runoff before it enters the water.
MM: If residents have questions about the city’s water resources, who should they call?
AS: Contact me in the city’s natural resource division at 952.988.8422.
MM: Aaron, thank you for talking with me today!
AS: Thank you, Mike.

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