FAQs • What are stormwater ponds?

What are stormwater ponds?: They are man-made basins built to capture and treat stormwater runoff until it can evaporate, infiltrate into the ground or flow through pipes into area streams, lakes or wetlands.

Water Resources

1. What is stormwater runoff?: Stormwater runoff is the water that flows off roofs, driveways, parking lots, streets and other hard surfaces during rain storms. Rather than being absorbed into the ground, it pours into ditches, culverts, catch basins and storm sewers.

2. Why is stormwater runoff a problem?: Stormwater can carry harmful pollutants, cause flooding, erode soil and stream banks, and destroy aquatic habitats.

3. Where does water pollution come from?: Water pollution is difficult to trace to a specific discharge point. Because pollution comes from many diverse sources, it is hard to control. Examples of common pollutants include fertilizers, grass clippings, pesticides, pet waste, sediments, oils and trash that are carried by runoff into the drainage system and environment.

4. What are some examples of drainage problems?: Drainage problems may include roadway or structural flooding, clogged or failing underground pipes and culverts, stream bank erosion and pollution affecting a stream.

5. What is the purpose of storm drains?: Storm drains are devices that capture stormwater in an effort to prevent flooding by transporting water away from urban areas.

6. What’s the difference between a sewer drain and a storm drain?: The sewer system and the storm drain system are two completely separate systems. The sewer system takes all household wastewater and routes it through a plumbing system into a treatment plant. The stormwater system routes rainwater off the streets, into the storm drains and may discharge into a bay, pond, stream or lake.

7. Who owns the stormwater system?: It depends. The county owns the stormwater system that is found within county rights-of-way or on county-owned properties. Cities own the same types of facilities within their jurisdictions and individual property owners own the rest. Currently, in most cases, the owner of record is the responsible party for surface water management.

8. What is an impervious area?: An impervious surface is any hard surface that does not absorb water and impedes the natural flow of water into the soil. In general, impervious surfaces include hard surfaces such as building garages, parking lots and basketball or tennis courts.

9. What are stormwater ponds?: They are man-made basins built to capture and treat stormwater runoff until it can evaporate, infiltrate into the ground or flow through pipes into area streams, lakes or wetlands.

10. Why do we have these ponds in our neighborhoods?: These neighborhood ponds are designed to catch and treat the runoff from neighborhood impervious areas, preventing many pollutants from reaching nearby lakes and wetlands.

11. Why does my stormwater pond look scummy, turbid or have algae?: Stormwater ponds are designed to capture and treat pollutants from runoff. Whenever it rains, stormwater rushes over impervious surfaces such as streets, sidewalks, roofs or parking lots and rapidly transports contaminants such as oils, salt, pesticides, heavy metals, and pathogens to these ponds. Stormwater runoff also delivers nutrients from pet waste, fertilizers, grass clippings and sediment to the ponds causing algae blooms and green coloring. Pollutant build-up in a pond is often an indication the pond is doing exactly what it was designed to do.

12. Can I swim in these ponds?: It is generally not advisable to use stormwater ponds for fishing, swimming or ice skating. They capture pollutants from stormwater and even low levels of pollution exposure (skin contact or fish consumption) should be avoided. Because water flows are unpredictable and pond levels fluctuate, ice formation on these ponds are not considered safe. Enjoy these ponds and the wildlife they attract from a distance.

There are many things a homeowner can to keep a pond looking clean and healthy.

Plant a buffer strip at the water’s edge, using native plants (not sod) to trap and clean runoff from your yard before it reaches the pond.
Pick up animal waste and properly dispose of trash.
Do not place lawn clippings, leaves or other yard waste within the pond basin.
Preserve established trees, shrubs and other vegetation around the pond.
Limit the use of fertilizers. Sweep driveways and sidewalks into lawns and gardens instead of hosing them off into the streets.