How Deep Are Retention Ponds? The Factors Explained

At first glance, retention ponds may appear to be just decorative water features, but they are crucial for managing stormwater runoff and protecting communities from floods and erosion. If you’ve ever wondered how deep a retention pond should be or what factors contribute to its depth, you’ll find the answers you’re looking for here.

Ready to discuss your retention pond maintenance needs? Call iSTORMWATER at (410) 231-3455.

What Are Retention Ponds?

Retention ponds are aboveground stormwater facilities designed to mitigate flooding and erosion that urban communities increasingly face due to excessive concrete, asphalt, and other non-porous surfaces covering the ground. Think of retention ponds as miniature dams that temporarily hold water when needed and release it in a controlled manner.

These ponds are used to manage urban runoff along roadways, near parking lots, and at commercial and industrial sites. Proper retention pond maintenance is crucial to keep the installation functioning properly, ensuring effective flood reduction and improved water quality.

Retention Ponds vs. Detention Ponds

While their names are similar, retention and detention ponds have distinct features that set them apart.

Retention ponds are always filled with water, their levels fluctuating in response to rainfall and runoff. These ponds collect and gradually release excess water through natural percolation. Because they lack an outlet structure, retention ponds rarely empty entirely; for this reason, they’re often referred to as “wet retention basins.”

On the other hand, detention ponds are usually dry unless significant rainfall occurs. Their primary function is temporarily holding water before directing it elsewhere until completely drained. Since they only control flood flows, detention ponds are sometimes called “dry detention basins.”

Both retention and detention ponds are integral for comprehensive stormwater management. Beyond meeting regulatory requirements, these ponds add natural beauty to developed properties, meaning they serve a practical and aesthetic purpose.

Average Retention Pond Depth

Are you wondering how deep a typical retention pond should be? If you’re building one or modifying an existing installation, remember that retention ponds have an average depth of 3 to 6 feet, although they can be as deep as 30 feet. In comparison, detention ponds are typically 3 to 12 feet deep.

The design and depth of a retention pond are calculated based on specific requirements, such as the amount of runoff it needs to handle. Retention pond basins are engineered with a specific slope ratio, usually 3 to 1, to optimize efficiency. This means that for every 3 feet the water level rises, the height of the side should increase by 1 foot. This design ensures that sediment and pollutants are effectively trapped while minimizing erosion around the pond’s banks.

Schedule With iSTORMWATER Today

If you’re looking for a reliable stormwater management partner, look no further than iSTORMWATER. With over 20 years of industry experience, we provide 24/7 services across Maryland, Virginia, Washington, DC, Pennsylvania, and Delaware.

Our certified engineers and project staff are committed to quality and attention to detail, ensuring long-lasting results that meet your needs. We offer upfront inspections, clear communication, and post-job follow-ups to guarantee your complete satisfaction. To help minimize business disruptions, we make it easy to schedule services when it’s most convenient for you.

Trust iSTORMWATER for all your retention pond management needs — call us at (410) 231-3455 today to request services.