Healthy plants, healthy streams: Upgrading County stormwater ponds

September 9, 2015

Ponds can provide great places to relax, have a picnic, or watch for wildlife. Most ponds in Montgomery County also act as filters to help clean and store stormwater after rain events. Read on to learn more about how the County is upgrading these important structures in our communities.

What is stormwater?

Stormwater is rain or snow that picks up substances like oil, grease, litter, pesticides, fertilizers, and carries them into our waterways, making them unhealthy. Most stormwater is not treated before it reaches nearby waterbodies, making it a major source of pollution.

How is the County managing stormwater?


Fallsberry dry pond

Fallsberry dry pond in Potomac, before being upgraded.


In efforts to improve the health of local streams, the Montgomery County Department of Environmental Protection is upgrading existing stormwater facilities to ensure that they are doing their best to capture and filter stormwater. In addition to upgrading existing ponds, the County also installs new facilities such as rain gardens or tree boxes and restores local streams.


Fallsberry pond plants being installed

Fallsberry pond during construction to convert it to a wet pond. The circles of dirt along the banks are newly planted vegetation that will help filter pollutants from stormwater.


A majority of our current projects involve converting dry ponds to wet ponds. Wet ponds allow us to plant vegetation that can absorb the pollutants that are released during storm events rather than passing directly into our streams. Along the perimeter of these ponds, we install Blue Flag Iris that have beautiful blue flowers, Pickerel Weed with an array of Purple flowers, Softstem bulrush, American bur-reed, and Water Lilies. All of these plants are native and attract many bees, butterflies, dragon flies, and birds.


Image of Fallsberry pond, 11 months after conversion to a wet pond

Eleven months after construction, Fallsberry wet pond is a thriving ecosystem!

Balanced ecosystems

Many of our residents are concerned when we propose wet ponds because they are worried that the water will become a breeding ground for mosquitoes. Once the wet ponds are completed, however, they are quickly surprised by how the balanced ecosystem of the ponds naturally keeps mosquito populations down. The goal of these projects is to create sustainable ecosystems where these ponds will enhance the habitat of our aquatic loving friends (frogs, birds, salamanders, ducks, etc.) but will also ensure there are more predators living in this system to control the mosquito population.

To learn more about the various projects that DEP is performing Countywide, please visit our Watershed Restoration group’s website where you can learn about other projects as well as use our interactive map to search for projects closest to your home!



6 comments on "Healthy plants, healthy streams: Upgrading County stormwater ponds"

  1. Marjorie Lane says:

    As a resident of the community, our new pond also brings mosquitos! I have lived in the area for over 17 years and never had a problem with mosquitos until the pond was built. Progress?

    1. Patrick says:

      If you measure progress solely on whether or not the mosquito population has increased then maybe not. If you measure it by some of the various other things listed in the article then maybe yes.

      1. Gwen Bausmith says:

        Hi Patrick,

        Thank you for your comment. The project goals included a balanced ecosystem to control the mosquito population, increased stormwater management, and reforestation of the area upstream of the pond. So far, we’ve planted over 60 trees and hope to plant more in the future!

    2. Gwen Bausmith says:

      Hi Marjorie,

      Thank you for your comment and for your concern regarding mosquitoes at Fallsberry pond. The last time DEP staff visited the pond, we sampled the water and did not find mosquito larvae in the water column. However, we would be happy to meet with you at the site and test the water again. We could also answer any other questions you may have at that time. If you would like to setup a time to meet with one of our planning specialists at the pond, please email us at Thanks!

  2. Allison Kenton says:

    Why don’t you show a picture of how the pond looks when it overflows its banks and comes up over the side walks. Some progress you made there in preventing flooding! Furthermore, the water is stagnant and filthy. How about getting a fountain or something in there to have some flow and prevent algae blooms. Why don’t you come out now to see how it looks – sure is different from above pictures!

    1. Gwen Bausmith says:

      Hi Allison,

      Thank you for your comment. During intense rain events, Fallsberry stormwater pond stores the incoming rush of water that would otherwise pass directly into local streams, causing erosion. This can occasionally affect the nearby sidewalk on the bank of the pond but helps prevent damage to soil in downstream areas.

      The pond is designed to capture runoff from nearby neighborhoods, so any pollutants found in those areas will be carried by rainwater into the pond. The pond acts as a storage area for that rainwater, allowing it to slowly drain into the local stream, while also acting as a filter to remove those pollutants.

      If you would like to meet with one of our planning specialists onsite to review some of these issues, please email us at We will be happy to set up a time to visit the pond and answer any additional questions you may have.

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