What is a Detention Pond?

Have you ever wondered what is a detention pond and what is it's purpose?

Heavy rain can turn your backyard into a swamp and threaten your basement with flooding.

A detention pond is a smart solution that captures stormwater runoff before it causes chaos.

This article will dive into what detention ponds are, how they function, and why they're essential for managing the deluge from our skies.

Stick around to become an expert on these unsung heroes of flood control!

Defining a Detention Pond

A detention pond is an area that holds stormwater temporarily and lets it out slowly. It helps to manage excess water especially during heavy rains.

The goal of a detention basin is to prevent floods by controlling the flow of water into lakes, rivers, and streams.

Detention basins catch runoff from impervious surfaces like roofs, roads, and parking lots, where water cannot soak into the ground.

They are sometimes referred to as 'dry ponds' when they are designed to be dry between rainstorms, but this term does not encompass all types of detention ponds.

These basins reduce soil erosion by slowing down fast-moving water. They play a crucial role in protecting areas downstream from getting too much water all at once.

In urban settings with many impervious surfaces, these structures are vital for stormwater control.

Differences and Similarities Between Detention and Retention Ponds

Detention ponds and retention basins both play roles in managing stormwater runoff.

They help to reduce flooding and control the amount of water that flows into sewers after heavy rains.

Detention ponds are engineered to temporarily hold and manage excess stormwater, gradually releasing it to mitigate flooding risks.

Over time, they release it slowly into the ground or back into water systems like rivers or lakes. This controlled release helps prevent flash flooding.

In contrast to detention ponds which are primarily designed for temporary water storage, retention ponds are engineered to permanently hold a specific level of water, thus serving a variety of environmental and aesthetic purposes.

These man-made reservoirs have two main goals: flood protection and improving water quality.

As for similarities, both kinds of ponds need upkeep such as debris removal, dredging to manage sediment, and vegetation control around the edges.

In addition to managing stormwater, they also serve as habitats for wildlife and contribute green spaces to urban environments.

Types of Detention Ponds

Discover the various kinds of detention ponds, each designed with unique features to effectively manage stormwater runoff - stay tuned to explore which type might best suit your needs.

Dry Detention Basins

Dry detention basins come into action during a storm. They temporarily store stormwater runoff from roads, rooftops, and parking lots.

These basins are engineered to release the stored water at a controlled rate, thereby mitigating the risk of flooding in nearby streets or residential areas.

When not in use, they may resemble empty grassy fields but become temporarily filled with water during and immediately after rainfall events.

They help manage stormwater by capturing it before it floods an area. After holding the water for a short time, they let it trickle out through designed outlets at a controlled rate.

This way, dry detention basins can efficiently control urban runoff and reduce stress on sewer systems.

Wet Retention Ponds

Wet retention ponds, which are permanently filled with water, function as natural filters for stormwater runoff, allowing pollutants like oil and debris to settle at the bottom.

This means cleaner water goes into lakes, rivers, or ground water. Plants around the pond add a green touch and help clean the water too.

Taking care of these ponds is important for them to work right.

Regular maintenance should include checking for blockages in the pipe orifices and repairing any areas where water has caused soil erosion.

They also have to clean out leaves and other debris that could stop water from flowing freely.

And because they create homes for birds and fish, these ponds can even be fun places to visit with room for things like boating or watching wildlife.

How to Build a Detention Pond

Step 1: Planning Your Detention Pond

The first step in building a detention pond is careful planning. 

It's vital to consult local regulations and obtain any necessary permits and having any underground utilities marked before starting. 

Choose a location where water naturally gathers, usually a low-lying area.

Then, assess the size of your pond based on the amount of rain your area receives and the size of the drainage area.

Step 2: Design Considerations

Design your pond to effectively manage water flow. The depth and slope are critical for handling water and maintaining safety.

Ensure the sides are gentle for easy maintenance. The bottom should be flat for sediment collection.

Include an outlet structure to control the water release rate. Professional assistance in design is highly recommended to ensure functionality and compliance with regulations.

Step 3: Excavating the Pond

Clear the selected area of any vegetation, debris, or other obstructions before excavation.

Using heavy machinery like excavators, dig out the pond according to your design.

Pay attention to the depth and shape to ensure it aligns with your plan.

Consistently check measurements during this process to guarantee the pond’s effectiveness.

Step 4: Installing Inlet and Outlet Structures

Construct an inlet for water to enter the pond and an outlet structure to control the release of water.

The outlet structure is crucial for managing the pond's water level, controlling the rate of water release, and preventing flooding.

It's essential to ensure that these structures are properly designed, installed, and maintained.

Step 5: Stabilizing Pond Banks

Stabilize the banks of the pond to prevent erosion. This can be done by planting grass or other vegetation.

These plants not only prevent erosion but also help in filtering pollutants from the water.

Detention Pond Maintenance Considerations

Detention ponds are important for stormwater management. They help control flooding and clean water before it returns to nature.

• Check the orifice often to stop clogs. An unclogged orifice makes sure water flows out of the pond correctly.
• Fix erosion right away. Soil washed away by water needs to be replaced to keep the pond's shape and function.
• Take out sediment and trash regularly. This keeps the pond deep enough to hold runoff water and reduces pollutants.
• Care for plants around the pond. Healthy plants stop erosion and soak up extra water.
• Inspect spillways and conduits often for damage. Repairs ensure that overflow moves safely away from the pond during heavy rains.
• Keep an eye on inflow points like gullies, culverts, and storm drains. Objects blocking these areas can cause backups and interfere with how the pond works.
• Control algae and unwanted weeds. These can take over a pond if not managed, hurting water quality.
• Test water quality to find any problems early. Monitoring helps manage pollutants that could harm local groundwater or surface water systems.

Detention Pond Landscaping & Design

Landscaping around detention ponds combines beauty with function. Plants, like grasses and shrubs, help to hold the soil.

This prevents erosion when storm water rushes in. Native plants are best because they handle local weather well and support wildlife.

They can filter pollutants from the storm water too.

Paths and benches turn a pond area into a spot for people to enjoy nature.

For safety, fences keep people away from steep or deep parts of the pond.

Designers also use rocks and wood to make the pond look more natural and control how water flows out.

FAQs

What is a detention pond?

A detention pond is an area designed to hold water and control stormwater runoff, helping to manage the flow of rainwater in drainage areas.

How do detention ponds work for storm water control?

Detention ponds function by temporarily storing stormwater runoff and methodically releasing it, often through engineered channels or discharge points, thereby reducing sediment and pollutants in downstream water bodies such as lakes and rivers.

Can a detention pond help with pollution?

Yes, by controlling sediment, a detention pond acts as a sedimentation tank that helps prevent pollutants from reaching our wetlands and other bodies of water.

Are there different types of detention ponds?

There are dry detention ponds that only hold water during rainfall events and extended detention basins designed for longer storage periods to improve stormwater quality.

Do we need anything else besides detention ponds for controlling rainwater?

In addition to detention ponds, rain gardens, bioswales, or infiltration trenches can be used as best management practices for enhanced storm water runoff control.

Conclusion

Now that you understand what is a detention pond and its crucial role in stormwater management, you can appreciate its importance in flood control and environmental protection.

They hold back floodwater and help keep our rivers clean.

These ponds also cut down on soil erosion from heavy rains. When designed right, they blend with nature and even add beauty to the area.

Detention ponds work hard for a safer and healthier environment.