As you drive or walk around our beautiful 35 acre campus, you might ask yourself, “why does Stone Ridge have so many landscaped swells in the ground?” If so, this article is for you!
The landscaped swells in the ground are stormwater retention ponds.
What is a Retention Pond?
A retention pond is a type of stormwater management facility designed to collect rainwater and pollutants and prevent downstream flooding. There are two types of stormwater retention ponds:
Wet ponds always have a pool of water.
Dry ponds only have water after rain. (Stone Ridge has only dry ponds on campus)
Retention ponds have an embankment (called a dam) to hold back water that is entering the pond. Most dams are earthen (not concrete) and are grass covered. All stormwater ponds also have a control structure that releases water at a much slower rate than the stormwater entering the pond. While water remains in the pond, pollutants have time to settle at the bottom.
Most ponds located throughout Montgomery County are stormwater management ponds, even ones that are community amenities. Ponds can have many different designs, including ponds with concrete channels, dry ponds with sand filters on the pond bottom, and ponds that provide wetland habitat around the edges
Stormwater ponds are important stormwater management tools, because they:
- Remove pollutants
- Improve health of streams and rivers
- Help to make our waters fishable and swimmable
- Improve the quality of the Chesapeake Bay
As rainwater flows over hard surfaces and lawns it picks up pollutants such as sediment, trash, pesticides from lawns, nutrients from fertilizer or pet waste, and oil and grease from cars. Ponds can help to reduce this pollution from entering our waterways.
Montgomery County EPA
In Montgomery County, Maryland, when you construct any new building or add a parking lot you are removing permeable surface, where water can soak into the soil. So the law says that you must install stormwater retention ponds to compensate.
The size of the stormwater retention pond is calculated based on the size of the roof structure or parking lot, so that they can hold all of the extra rainwater that falls on these surfaces and runs off.
The cost of designing, constructing and maintaining stormwater retention ponds must be calculated into any new construction project per Montgomery County law.
How many Stormwater Retention Ponds does SR have on campus?
Where does our stormwater go?
Water that is collected into our stormwater retention ponds is designed to absorb into the ground.
Water not collected in a stormwater retention pond ultimately flows toward Cedar Lane and makes its way into Rock Creek.
How do we maintain our Retention Ponds?
As the property owner, we are responsible for all maintenance of our stormwater ponds — Ponds on private property of the responsibility of the owner.
Stormwater ponds require regular maintenance similar to other landscaped areas, including grass cutting, trash removal, and vegetation management.
- We trim the vegetation and cut the grass in our stormwater ponds on a routine basis.
- We weed and rake the gravel at the 2 ponds with sand filters.
- We have an outside vendor who cleans out the underground stormwater vault at Gator Field twice a year.
- Montgomery County will inspect our stormwater facilities every three years.
- The inspections will typically result in a list of deficiencies, usually related to sediment build-up or erosion, that must be taken care of or fines will be assessed.
If we don’t maintain our ponds they may:
- Not remove pollutants as intended, sending polluted water to streams and rivers
- Become filled with sediment and debris, so water cannot be stored in the facility, which may lead to downstream flooding and erosion
- Look unsightly with excessive growth of unwanted weeds or algae
- Cost more to fix problems if left unchecked
- Lead to a dam breach if overgrown vegetation and trees compromise the pond safety over time. This would cause flooding and damage to surrounding properties and adjacent homes
- Have inlet and outlet areas blocked by excessive growth or debris. This will cause water to back up.