Staff

Seidl, Joe
Water Resources Engineer
- (952) 227-1168
- jseidl@chanhassenmn.gov

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FAQs

What is the odor coming from the pond?

Rotting organic matter, water turnover, or certain types of algae are typically the main sources of bad odor. Organic matter decays at the bottom of the pond when it is stagnant and poorly oxygenated and sulfur-dioxide is released as a by-product of the decomposition. When the water is disturbed by way of cool wind or heavy rainstorms, the odor comes to surface.
Why are there so many geese?

The ideal habitat for Canadian geese is mowed Kentucky bluegrass contiguous with a body of water. A significant way to prevent geese from impending your pond is to stop mowing to the shoreline. This gives geese easy access in and out of the water and is a desirable habitat for them. There are a variety of methods for control geese but establishing a buffer of native plantings along the water’s edge is the most effective. This will not only deter geese but it will also provide water quality benefits. More information on geese can be found on the MN DNR website.
Why is the pond green?

During summers, small neighborhood ponds can get a little green. But that green doesn't mean the pond has poor water quality. Naturally, most people assume green on a lake or pond is algae, but often the green on top of your water is actually duckweed. Also known as duck’s meat or water lentil, duckweed is actually tiny, free floating native plants. The plants are found in clusters of leaves, each with small roots that hang down into the water. It can form thick green blankets on the water’s surface which is why it is often mistaken for algae. Duckweed is found in quiet waters of ponds, lakes and streams and will rarely become abundant on waters with frequent wind or lots of wave action.

Other sources of green color include blue-green algae, or cyanobacteria, which can be harmful with prolonged or frequent exposure. Algae blooms are caused by heat and excessive amounts of nutrients such as nitrogen and phosphorus. Some of the most common sources of nutrients include fertilizers, grass clippings, and animal waste.

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Ponds

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Overview

The primary purpose of many ponds in Chanhassen is to collect stormwater runoff (rain and snow melt) and reduce the risk of flooding. Ponds filter out pollutants and sediment, thus making them an essential step in protecting water quality as stormwater travels downstream toward Chanhassen’s lakes, streams, and wetlands. The city performs inspections of stormwater ponds on about a 5-year cycle to ensure ponds function as designed. The city does not manage ponds for aesthetic purposes. However, the city understands that residential ponds can often become a source of undesirable aesthetic conditions that residents may want to manage. Luckily, there are a few ways to mitigate against that.

There are a few tips and tricks that residents can employ in order to help improve water quality in their ponds:

Rake trash, leaves, and grass from yards, streets, and curbs. Sweep driveways and sidewalks instead of hosing them off.
Never dispose of yard waste (or anything else) into ponds and storm drains – the waste contains phosphorus, which causes plants and algae to grow.
Use biodegradable soaps for outdoor cleaning or car washing.
Pick up pet waste and dispose of it in the trash.
Maintaining a native, vegetated buffer around a pond goes a long way toward filtering out stormwater as it travels overland into the pond. This may not always be the most desirable option from a maintenance and aesthetic choice, but even maintaining healthy sod and grass will help a little bit in this regard.
Reseed or re-sod all bare areas to keep stormwater from washing soil particles (which also contain phosphorus) into a storm sewer or pond.

Please note – stormwater ponds are not to be used for human or pet recreation.

The city inspects ponds roughly once every five years. However, in the summer and fall of 2020, city staff performed a comprehensive inventory of all our ponds and devised a prioritization plan for maintaining them based on collected data. In the past, budgeting for pond projects was severely limited. However, in the fall of 2020, the City Council approved an increased budget for pond maintenance projects. As a result, the plan moving forward is to evaluate pond maintenance projects on an annual basis.

Why is My Pond Green?

Is a pond in your neighborhood looking pretty green? Watch the following video to learn why that might be.