Common Concerns about Ponds & Lakes

The primary purpose of many ponds in Burnsville is to collect stormwater runoff (rain and snow melt) and reduce the risk of flooding. The City performs inspections of stormwater ponds on about a 5-year cycle to make sure that ponds function as designed. The City does not manage ponds for aesthetic purposes.

Property owners with ponds may choose to enhance ponds for aesthetics or recreation purposes if allowed by City ordinance or State law. Below is a description of common pond issues and suggestions for improvement.

Aquatic plantsCommon Concern #1: Pond is Weedy

What you see as weeds may be part of a normal pond environment. Native aquatic plants are essential to pond health. Plants provide food and shelter for wildlife such as birds and fish. Plants also absorb excess nutrients from the water and prevent shoreline erosion. Knowing what a healthy pond looks like can help adjust your expectations for your pond's appearance.

Sometimes, invasive plants may be a problem. If one plant seems to be taking over your pond, try to identify what it is. Check out the Minnesota Department of Natural Resources (DNR) guide to invasive aquatic plants.

If you want to control aquatic plants in your pond, you first need to determine what you're allowed to do. Check out the information about regulations under Aquatic Plants.

Hand holding duckweedCommon Concern #2: Pond is Green

If tiny green plants are floating on the water's surface, you probably have duckweed. These tiny, native aquatic plants provide food and shelter for wildlife. Green blobs or fuzzy strings? You may have filamentous algae. If the water itself is green, it's probably microscopic plankton algae. Some algae is normal, but too much algae reduces water clarity, which upsets plant growth and the natural food chain.

The best way to reduce algae is to reduce the amount of phosphorus and other nutrients entering your pond. For tips, scroll down to "Help Protect Water Quality" at the bottom of this page. Keep in mind that the MN DNR regulates the control of algae and aquatic plants such as duckweed in any waterbody designated a "Public Water." Learn more on the Aquatic Plants page.

Healthy sunfishCommon Concern #3: Dead Fish

In early spring, after ice-out, dead fish may be seen along the shoreline. Usually this is a common occurrence after a harsh winter when ice and snow limit the amount of sunlight reaching into the water. With little light, aquatic plants photosynthesize less, producing less oxygen. Low oxygen levels in the water cause some fish to suffocate. A similar situation can happen in summer after an algae bloom and subsequent die-off. Decomposition of the algae uses up oxygen, making less available for fish.

Toxins and disease also kill fish. If you see a large number of dead fish and you don't think it's related to a winter fish kill, report it to the City Natural Resources Staff at 952-895-4550.

Filamentous algaeCommon Concern #4: Smelly Pond

Smells from a pond are usually caused by plant decomposition and will subside over time. An algae bloom and subsequent die-off is often the culprit. The best way to prevent future smelly problems is to prevent algae blooms. This is best done by reducing the amount of phosphorus and other nutrients entering your pond.

For tips, scroll down to "Help Protect Water Quality" at the bottom of this page.

Help Protect Water Quality in Ponds & Lakes

Water quality is an important issue that impacts everyone, and we are all responsible for protecting our water resources. Here are some simple things that you can do to help

  • Reduce runoff. When rain and snowmelt run off your driveway, it washes pollution into storm drains, which lead straight to your neighborhood pond. Reduce runoff by directing your downspouts onto your yard, not your driveway. You can also install a rain barrel or build a rain garden to capture runoff.
  • Keep fertilizer on the lawn. It's illegal to leave fertilizer on hard surfaces such as driveways, sidewalks, and roads because the fertilizer can wash into storm drains. Also, fertilizer may not be used within 20 feet of the edge of any wetland, pond, or lake.
  • Rake leaves, grass clippings, branches and other yard waste OFF the street. Yard waste debris can be unsafe for traffic and may cause flooding by plugging up storm drains. Learn about composting and where to take yard waste.
  • Pick up pet waste and put it in the garbage. Rain and snowmelt runoff can wash pet droppings into storm drains and ponds. As it decomposes, the droppings release bacteria (E. coli, salmonella), parasites (Giardia), and nutrients (such as phosphorus) into the water.
  • Wash vehicles on the lawn, not on your drivewayThe soapy water won't hurt your grass, but if it ends up in a storm drain it can harm your neighborhood pond.
  • Keep it clean. Sweep grass clippings off your driveway, sidewalk, and street. Clean up spilled lawn fertilizer, oil, and other chemicals, and dispose of them properly. Remember that anything on your hard surfaces may be washed into a storm drain.
  • Reduce or eliminate winter salt use.  Instead of salt, try using sand or non-clumping kitty litter for traction on ice. Shovel snow as soon as possible to keep your walkways clear and prevent ice-buildup so that you don't need salt. If you do use salt, read package directions so that you don't over-apply. Keep in mind that, in general, you need less than 1 pound of salt per 250 square feet (roughly the size of two average parking spaces). This amount may be less than you think – a 12-ounce coffee mug holds about a pound of salt.