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What is a retention pond?

What is a Retention Pond?

What is a retention pond and what is its purpose? Retention ponds are key players in managing stormwater runoff, ensuring our streets and homes stay flood-free.

In this article, we'll uncover what retention ponds are, their importance, and how they benefit your community.

Keep reading to dive into the world of water management made simple.

Understanding Retention Ponds

Now, let's look into what retention ponds really are.

A retention pond is an engineered structure designed to collect and store rainwater runoff, functioning as a critical component in urban water management.

Instead of water quickly running off into streams or sewers, these ponds keep it around for a while.

A serene retention pond with lush greenery and wildlife.

They have grassy sides and plants all around to make them look nice and help clean the water.

Retention ponds commonly feature a constant water level, akin to small lakes, and are engineered to gradually release accumulated water through either controlled methods or natural ground infiltration.

These ponds do important work by slowing down stormwater runoff from places like roofs, parking lots, and streets.

This helps stop flooding and means less trash and dirt getting washed away into rivers or lakes.

While they can provide habitats for certain aquatic species, the biodiversity supported by retention ponds varies and is influenced by pond design and maintenance, as well as local environmental factors.

In cities with lots of buildings and concrete, retention ponds give rainwater an open place to go so sewers don't get too full during big storms.

The Difference Between Retention and Detention Ponds

When managing stormwater, it's crucial to distinguish between retention and detention ponds, as they serve different purposes in water management strategies.

A retention pond surrounded by urban buildings and drainage infrastructure.

Let's explore how these two types of ponds function and what sets them apart from each other.

Key Differences

Retention and detention ponds are critical structures for managing stormwater, but they serve different purposes and have distinct features.

Let's explore the key differences between them:

  • Water Presence- A retention pond has a permanent pool of water where a detention pond is a temporary storage for runoff
  • Primary Purpose- Retention ponds are primarily designed for flood control while also aiding in water quality improvement. Conversely, detention ponds are focused on temporarily storing stormwater, predominantly for enhancing water quality and providing secondary flood control.
  • Space Requirement- Retention ponds generally require more space, while detention ponds can be designed to be smaller and more adaptable to available space.
  • High Quality Impact- Retention ponds contribute to water quality improvement through natural processes like sediment settling and biological activity. Detention ponds primarily manage flood flows, with limited capacity for water quality improvement, relying on sediment settling and optional filtration methods.
  • Mosquito Breeding- Both retention and detention ponds can become breeding grounds for mosquitoes if not properly maintained, due to the potential presence of stagnant water.
  • Property Value Impact- The impact of retention ponds on property values can be mixed, depending on their design, maintenance, and integration into the surrounding landscape. A detention pond may have recreational and habitat creation benefits.
  • Design Complexity- A retention pond is simpler if adequate space is available where a detention pond can be more complex due to added infrastructure for water processing.
  • Environmental Impact- A retention pond creates new habitats and a detention pond may pose a drowning hazard if not properly designed.

Retention ponds not only manage stormwater but also offer flood control benefits.

Conversely, detention ponds mainly focus on water quality improvement and provide short-term flood relief.

These differences are essential to consider when choosing the right pond for a specific location and purpose.


Understanding the commonalities between retention and detention ponds is essential for grasping their role in stormwater management.

Below is a comparison in table format for quick reference, revealing their shared characteristics:

  • Hold water during heavy rainfall
  • Prevent flooding by managing stormwater
  • Require regular maintenance
  • Improve water quality by trapping pollutants
  • Provide habitat for wildlife
  • Create recreational opportunities
  • Require proper design for effective stormwater management

Both ponds serve critical functions in contemporary land development, contributing to environmental protection and sustainable water management practices.

The Importance of Retention Pond Maintenance

Ensuring the proper function of a retention pond is crucial for managing stormwater and maintaining environmental health.

A retention pond surrounded by urban buildings and drainage infrastructure.

Regular maintenance helps prevent issues such as erosion, water contamination, and habitat disruption which can otherwise have costly and long-lasting impacts on our urban and natural ecosystems.

Erosion Prevention

Retention ponds catch stormwater runoff. This helps to slow down the water and stops soil from washing away.

With less fast-moving water, gullies and erosion near roads don't form as easily.

Keeping the pond's orifice clear is a big job. It must stay open so the water can flow right. If it gets blocked, erosion could get worse.

Vegetation around retention ponds works like a shield for the soil.

Plants hold the dirt in place with their roots which prevents it from eroding into the pond during rainstorms. Sometimes parts of a pond start to erode.

Fixing these spots quickly keeps them from getting bigger and causing more harm to the pond's structure.

Taking out sediment and trash also helps stop further erosion by making sure there is enough room for water in the pond.

Regular Mowing

Mow the slopes around your retention pond regularly.

This keeps the grass at a healthy height, which helps stop soil erosion and protects water quality.

Change up the mowing direction each time to keep the ground firm and even.

After you've finished mowing, take a look for unwanted weeds.

Control of Weeds

Taking care of weeds is a big part of keeping a retention pond healthy.

Invasive plants like phragmites can choke out other plants and mess up the water flow if they're not managed.

People who look after ponds must spot these aggressive growers early and stop them from taking over.

They use special methods to keep the ecosystem balanced.

Cutting grass on the pond banks makes sure weeds don't spread too much.

Workers change the mowing pattern each time to help with this.

By doing that, they protect against erosion while also fighting off invasive species.

Clearing out these unwanted plants keeps the water clean and ensures everything in the pond works right.

Keeping Ponds and Basins Clean

After tackling weed overgrowth, attention turns to the cleanliness of ponds and basins.

Clearing trash and debris from water is crucial for a healthy pond environment.

This prevents blockages in storm drains and keeps water flowing smoothly.

Regular cleanups stop trash build-up and maintain the beauty of these man-made lakes.

Using nets or skimmer tools helps remove floating junk from the surface.

It’s also important to inspect spillways and embankments for any waste that could cause problems.

Keeping aquatic vegetation under control ensures that submerged plants don't choke out the pond's ecosystem.

A clean retention pond functions better, looks nicer, and supports a balanced habitat for wildlife.

How to Build a Retention Pond

Building a retention pond helps manage stormwater runoff and prevents flooding. It's a big job that requires planning, design, and construction.

Engineers design a retention pond under construction with a bustling atmosphere.
  • Choose a location: Find a spot where water naturally collects or where runoff from storms can be directed. The area should have enough space for the pond and be far from buildings.
  • Design the pond: Work with engineers to create a blueprint. Designs must include a sediment forebay, permanent pool, temporary storage, and wetland planting zones.
  • Get permits: Contact local authorities to get necessary approvals. This might involve meeting environmental, safety, and land-use regulations.
  • Prepare the site: Clear the area of trees, rocks, and debris. Make sure the soil is right for holding water without leaking.
  • Shape the pond: Excavate soil to create the basin. Slopes should be stable but not too steep to prevent erosion.
  • Build structures: Construct dams or spillways using concrete or earth. These will control how water goes in and out of your pond.
  • Install an aerator: Put in an aerator device to keep water moving. This stops mosquitoes from breeding and helps aquatic plants grow.
  • Place controls on inflow and outflow: Install features that manage how fast water enters and leaves the pond. This helps deal with heavy rain without causing floods downstream.
  • Add plants around the edges: Plant native shrubs and flowers that can handle wet conditions. They make your pond look good and provide habitat for wildlife.


    What is a retention pond?

    A retention pond is a man-made lake that collects stormwater runoff from streets, roofs, and green infrastructure to prevent flooding.

    How do retention ponds help during heavy rain?

    Retention ponds use gravity to accumulate stormwater, which is then either slowly absorbed into the ground or methodically discharged, helping to mitigate flood risks.

    Can a retention pond be good for wildlife?

    Yes! Retention ponds create habitats where fish and aquatic plants live, and they also attract birds and other wildlife looking for food and shelter.

    Why do some neighborhoods have dry detention basins?

    Dry detention basins are like empty swimming pools that stay dry until rain fills them up; they manage surface runoff without taking up space with water all the time.

    Are there benefits of having submerged aquatic vegetation in these ponds?

    Submerged aquatic vegetation helps keep the water clean by settling dirt out of surface runoff, providing oxygen for underwater life, forming an artificial wetland ecosystem.

    What's done to maintain the health of a retention pond?

    People work on soil conservation around the slopes, remove trash with dredging when needed, check groundwater levels, and make sure underwater plants thrive for ecological balance.


    Now that we've thoroughly answered the question "what is a retention pond" you are now aware of their importance to our environment.

    Retention ponds play a vital role in managing stormwater, especially in urban areas.

    These ponds also keep our water clean and provide homes for plants and animals.

    By building and taking good care of retention ponds, we create healthier spaces for everyone to enjoy.

    Previous article Retention Pond vs Detention Pond

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