Managing stormwater is a necessary part of water management in the Atlanta metropolitan area. This is particularly important during storms to prevent flooding, erosion and runoff.
One way commercial properties manage stormwater is through detention ponds and retention ponds.
These ponds, which can vary in size and shape, help slow heavy water flows to avoid floods and act to improve the quality of urban runoff from roads, parking lots and commercial and industrial areas by filtering water.
The terms detention pond and retention pond seem to be used interchangeably when referring to these types of ponds or basins since they both are designed to capture and store runoff; they can even be similar in design.
However, detention ponds and retention ponds differ in purpose.
What is a retention pond?
The definition of retention is “the capacity to hold; the state of being retained.” So a retention pond is designed to hold a permanent pool of water that fluctuates in response to precipitation and runoff.
Usually, retention ponds are designed to have drainage leading to another location when water levels reach beyond a certain point. However, they continue to maintain a certain water capacity.
Maintaining a water pool can also help keep deposited sediments at the bottom of the holding area, improving water quality.
What is a detention pond?
Detention, on the other hand, means to “momentarily withhold something” or “delay an action.” In this case, a detention pond—or dry pond—is an area where excess stormwater is stored or held temporarily and then slowly drains when water levels in the receiving channel recede.
In essence, the water in a detention basin is briefly detained—over a period of 24 hours, for example—until additional room becomes available in the next conduit. These are extensive in the Atlanta metropolitan area.
Detention ponds come in handy during large storm events, which can contribute a significant volume of runoff moving at an increased speed, raising the potential for erosion and flooding, particularly downstream. When the rain stops, detention ponds will be empty shortly afterward.
Detention ponds have been especially important in Georgia this year. In 2013, it has rained in near record volumes in the metropolitan Atlanta area, according to the National Weather Service.
The area has seen more rain through July 8 this year than it saw in all of 2012 and also in all of 2011. Keith Stellman, meteorologist in charge of the Peachtree City-based weather service, says even if the area gets only average rainfall the rest of the year, it will still be one of the top ten wettest years on record.
Maintenance makes them work
In order to operate successfully, both detention ponds and retention ponds require regular maintenance. Inspections, debris removal, vegetation management, bank stabilization and structural checks are all important to ensure detention and retention ponds are ready to do their jobs when storms or heavy rains occur.
Wondering if your ponds will be able to withstand more heavy rains this year? Give our professionals a call at 678-298-0550 or use the contact form to the right to schedule a free consultation. And if you enjoy reading our helpful tips, be sure to subscribe to our blog!
Image credit: antpkr