Skip to Content

What Are Retention Ponds Used For? (Plus the Pros and Cons)

What Are Retention Ponds Used For? (Plus the Pros and Cons)

Share this post:

This post may contain affiliate links. If you click an affiliate link and make a purchase, I may earn a commission. Also, as an Amazon Associate I earn from qualifying purchases.

If you’ve seen a pond-like structure with gravel and vegetation surrounding its perimeter, you’re more likely eyeing a retention pond. You might be wondering: what are retention ponds used for?

Retention ponds, otherwise known as retention basins and wet ponds, are artificial structures used to retain and treat contaminated stormwater runoff. They also control flooding and downstream erosion and improve the quality of water in nearby rivers and streams.

In this guide, we’ll dive deeper into the functions and benefits of this important artificial structure. We’ll also answer some of the common questions tied to this topic to enlighten you further, so stick around!

How Do Retention Ponds Work?

Here’s how retention ponds work in general:

Retain Water to Prevent Flooding

As the name suggests, the job of this stormwater structure is to retain a pool of water.

During the event of a storm, water runoff from streets and even from the roof of houses go to the retention pond.

Mostly, retention ponds have a forebay that receives the initial flow of water. Then, the water flows to the second pool, or what we call a permanent pool.

The permanent pool has a narrow outlet or riser placed at the higher level. Once the water level reaches the outlet, a gradual flow of water is released, deterring downstream flooding.

Filter Pollutants in the Stormwater

This structure filters the pollutants present in the water through the sedimentation process. It’s basically where the still water allows the heavier sediments to settle at the bottom and form a layer of sludge.

The initial settlement of sediments occurs in the forebay and continues in the permanent pool.

Often, retention ponds are landscaped with a variety of grasses and shrubs which block pollutants from washing into the ponds. They also have aquatic plants, gravel, and sand which help in filtering the pollutants.

How Effective Are Retention Ponds?

Well-constructed and well-designed retention ponds are quite effective in controlling stormwater runoff, flooding, and other environmental issues.

However, its effectiveness may wane over time as sediments pile up at the bottom.

To ensure this structure will function effectively, regular maintenance is necessary.

How Do You Maintain Retention Ponds?

Parts of the retention pond maintenance plan include the following:

Clearing the Debris Blocking the Outlet and Inlet

Inlets and outlets have the tendency to trap debris and sediments over time. Hence, they need to be inspected for clogging at least twice a year.

Trash, dirt, weeds, and grass can accumulate in the stormwater system, so you’ll need to get rid of them regularly.

Controlling the Grass and Shrubs

The vegetation around the pond helps in filtering the stormwater pollutants, but you shouldn’t let them overgrow.

You can trim or mow your pond’s bank once a month during the growing season.

Make sure to mow in different directions, as the same mowing pattern directs the water to gush in the same location. This might lead to soil erosion.

Cleaning the Forebay

Once the forebay accumulates 6 inches of sediments, you’ll have to clean it.

Stocked sediment can impact the volume of water the retention pond can retain.

Monitoring the Pond

After every storm, you’ll need to monitor the surroundings of the retention pond for possible cracks and soil erosion. Regular monitoring will help you take the necessary corrective measures.

Pollutants are washed into the pond along with stormwater, so you should also watch out for any significant change in the quality of water.

Who Is Responsible for Retention Ponds?

If you own an area of land where the retention pond is, you’ll be responsible for maintaining that parcel of land.

Yet, most of the time, homeowner associations and city governments take over the maintenance of the retention ponds.

Nonetheless, make an effort to know if you hold any responsibility as neglect of this crucial structure often leads to violations and fines.

Regardless of who owns and who’s responsible for these water features, the public should also take part in the goal of keeping them clean.

The community can keep the stability of retention ponds by not throwing trash on the streets. Not spraying insecticides and herbicides when there’s an impending storm is such a huge help, too.

Can You Eat Fish From a Retention Pond?

Some people who fish in retention ponds have caught bluegill, sunfish, shell crackers, largemouth bass, and more. Although these fish are edible, not everyone has an appetite for them.

This is due to the fact that agricultural and industrial pollutants from the neighborhood go into these stormwater basins. Therefore, eating fish from contaminated ponds may pose health problems.

However, if you go over the internet, you’ll realize that a number of people are proud to say they’ve tried eating fish from a retention pond. If you want assurance that the water in the pond is clean, though, you can purchase an inexpensive test kit and test the quality of the water.

If you’re not confident that it’s clean enough, then you shouldn’t eat fish from it. It all boils down to how willing you are to take a risk.

How Deep Are Retention Ponds?

Retention ponds can go 3–6 feet deep. This depth is generally sufficient to keep a healthy environment within the pond.

However, this artificial structure can also have a maximum depth of 10 feet.

In essence, the artificial pond should be shallow enough to prevent anaerobic conditions at the bottom. Yet, it should also be deep enough to curtail algal blooms and the suspension of deposited materials.

The mean depth of an artificial pond can be calculated by dividing its storage volume by its surface area. Hence, the depths of retention ponds usually vary.

Why Is My Retention Pond Not Draining?

If your retention pond isn’t draining, then it’s probably because of weeds, grass, or silt buildup. Excessive amounts of debris can block the outlet and cause it to stop draining the water.

For this not to happen, make sure to remove the unwanted debris and maintain your pond regularly.

Nonetheless, note that retention ponds are designed to retain a certain amount of water, which will rise and fall depending on the amount of rain runoff. As such, the permanent pool will always have water in it and won’t dry out completely.

What Are the Pros and Cons of Retention Ponds?

To know if building a retention pond within your property is worth it, we’ve compiled its pros and cons.

Pros of Retention Ponds

  • Control the quality and quantity of rain runoff
  • Prevent flooding in the neighborhood
  • Promote removal of urban pollutants
  • Provide potential ecological and recreational amenities
  • Easy to create and easy to maintain
  • Improve the aesthetics of the site and give an added property value
  • Provide a home for new plants, fish, and other forms of wildlife
  • Offer water supply for fire protection

Cons of Retention Ponds

  • Without good water inflow, anaerobic growth conditions can occur
  • If designed poorly, a retention pond will have a negative impact on water quality and become an eyesore.
  • Require a big land space
  • May present a drowning hazard

Final Thoughts

Retention ponds are used to address the quality and quantity of stormwater that impacts land development. These important structures prevent flooding and soil erosion that threaten cities around the globe.

On top of this, retention ponds provide a home for wildlife creatures, recreational amenities for people, and an added aesthetic for a more dynamic community.


If you want more backyard tips including recipes, how-tos and more, make sure you subscribe to my youtube channel

Share this post: