Retention ponds play a crucial role in modern urban planning and development, addressing both environmental concerns and practical challenges associated with water runoff. It’s useful here to understand the difference between a Retention Pond and a Detention Pond. A Retention pond is designed not only to capture surging water but also to hold it indefinitely, and thus is also called a “wet pond” – distinguishing it from a “dry pond”, which is a Detention pond, only intended to capture excess runoff water, and most times standing dry and empty.
Water management in a city is a principal task to protect infrastructure and quality of life. Retention are designed to capture water runoff that accrues from downpours of rain or other surges of water, holding the water back from flooding farther downstream. Oftentimes, this runoff accumulates from impermeable surfaces such as roads, parking lots and buildings, which are all increasingly prevalent as towns grow, and permeable land is built over. By collecting and managing this runoff, retention ponds help prevent flooding during heavy rainfall, holding water back from overflowing city storm drain systems.
A retention pond also serves as a natural filtration system, trapping pollutants and allowing them to settle out of the water. Harmful substances such as fertilizers, petroleum products, sediments, construction debris and metals are separated from the water, while biological processes involving algae and bacteria work to break down and consume these pollutants, further purifying the water.
Retention ponds offer a controlled solution, ensuring that runoff is captured and managed in a way that minimizes environmental and structural risks. Usually they’re designed to allowed for controlled releases downstream after the surge has passed, to lower the level enough to accommodate more water, while still retaining enough water to constitute a viable water containment pond. Landscaping to prevent erosion of the banks is often added, and some ponds can become civic amenities for recreational use and as wildlife habitat.
Containment is the key to a successful retention pond, and companies such as Western Liner can provide a suitable retention pond liner for the pond used by cities or construction sites. Geomembrane pond liners can be used in retention ponds to prevent pollutants and chemicals from seeping into the groundwater, thus helping protect the environment and the drinking water supply. Many pond liners are made from reinforced polyethylene (RPE), which is becoming more popular for such containment applications because of its high chemical-resistant, tear-resistant, and puncture-resistant properties.
As cities and towns continue to expand, retention ponds are becoming a standard feature of new developments. Their ability to manage runoff, mitigate flooding, and reduce pollution makes them indispensable in areas with significant construction activity. When properly installed and maintained, these ponds not only support sustainable urban growth but also enhance environmental protection.
