A flooded parking lot at a retail property does more than cause soggy feet. It can negatively affect local water quality, cause erosion, chase away customers and give the entire property a bad name.
When stormwater falls on hard surfaces like parking lots, roads, paved sidewalks and walkways, driveways and rooftops, it cannot seep into the ground so it runs off into other, mainly lower, areas. Because more water runs off of hard surfaces, local flooding can occur. High volumes of water can even cause stream banks to erode and wash wildlife downstream.
As this water flows, it can also pick up anything in its path, including any chemicals, and carry it to nearby by streams that feed into rivers, lakes and oceans. So pollution becomes a big concern with stormwater runoff. And this is why many municipalities in Georgia require commercial development to have stormwater management plans.
But there’s a solution to your stormwater woes! There are three main ways to manage stormwater on a retail property: retention ponds, detention ponds and underground detention ponds. Here’s how they work.
Retention & Detention Ponds
Retention and detention ponds, or stormwater basins, collect stormwater as it builds and slowly releases it at a smooth, controlled rate so that downstream areas are not as risk for flooding or erosion.
Though they both use the word “pond” in their description, only one is like a traditional pond. A detention, or dry, basin is built so that all of the water eventually drains from it so it is dry between storms (unlike a traditional pond). Retention basins, on the other hand, are built so that they retain a permanent pool of water.
Both retention and detention ponds do their important jobs of storing and slowing stormwater runoff from roads, pavement and roofs. Retention basins can provide additional water quality benefits by reducing sediments in the water.
Underground Detention Ponds
Today, a popular method for retail centers to use for managing their stormwater runoff is an underground detention basin. As parcels of land are getting smaller for retail space—less than a couple of acres, for instance—and room is needed for buildings or parking, putting an underground detention pond under parking decks is becoming a common trend in Atlanta.
This type of pond acts just like a regular detention pond, but is just stored underground since there isn’t space on the site for the above ground detention pond. It’s important to ensure there’s proper drainage into an underground detention pond and that the pumps installed are able to handle the water flow and drainage.
The Importance of Even Stormwater Flow
The goal with any of these ponds is the smooth flow of water. Municipalities today want property owners to ensure the stormwater entering and exiting their sites has an even flow rate, meaning the water comes onto the property and leaves the property at the same rate of speed, or flow.
Maintenance Matters Most
Once a retention pond, detention pond or underground detention pond is in place, proper inspections and maintenance are essential to ensure the system is doing what it was designed to do.
Give HighGrove Partners a call at 678-298-0550 and we can help you with your stormwater management plans, as well as maintenance and repair of your retention or detention systems to keep them working efficiently.
Image credit: Flood warning