Gwinnett County Watershed Improvement Program Riverside Parkway Stream Restoration and BMP Program (Best Management Practices) Located on county-owned public property (placed with permission) at Riverside Parkway, near McKendree Elementary School. Do not park at McKendree ES during the school-week. You will need to find public parking and then walk to the site.
Gwinnett County implemented a stormwater utility in 2006. This utility provides support for major stormwater activities such as replacing stormwater pipes, reducing flooding, fulfilling regulatory requirements, and reducing pollution carried by stormwater to our waterways. This earthcache site features a restored stream and constructed wetlands.
Wetlands have significant environmental benefits. One way that pollution to waterways is reduced is by creating constructed wetlands. This stream at Riverside Parkway was being scoured (the banks of the stream being eaten away) by high volume and high velocity stormwater runoff created by development. The rainfall does not have time or opportunity to soak into the earth as it did 100 years ago. High volume rainfall events now carry surface pollutants like lawn fertilizer, motor oil, pet waste, and anything else found on roads, rooftops and parking lots directly into the streams. The streams go into creeks, and the creeks go into lakes, which provide our drinking water.
During periods of regular weather, the stream follows its traditional course. During periods of high rainfall, when the streams become loaded with suspended pollutants carried away from impervious surfaces, the water is diverted from its regular route and instead flows into a series of ponds. Pollutants settle out of the water and biodegrade naturally in the ponds. The water goes through a number of settling opportunities with each high-volume rainfall event. Then it flows into the natural wetlands where it is further naturally filtered until another high volume rainfall event pushes the now-clean water out into the stream again.
These man-made (constructed) wetlands have a series of small ponds to filter the high-volume stormwater. Each pond is dammed by natural hardwood logs which were harvested on the site. They are stacked three deep (three logs atop one another) and the length of the log which is visible is only a small fraction of the actual log. They are called K-dams because if you look at them, they are assembled in a way which looks like the alphabet letter “K”. That keeps them stablilized and from being washed away.
Question #1: How many “K” dams are there? Question #2: How many storm drain pipes dump into this stream as it passes under Riverside Parkway? As you walk to the coordinates: N 33° 58.688 W 084° 01.486 - the backside of the earthcache, you may pass over several foot bridges and past several park benches. After passing the last park bench, look ahead to where the now-clean-filtered water is coming out of the natural wetlands. At that point, look to your left. Question #3: What is the name of the unusual loose-plated-bark trees which are abundant there? (A photo is posted).
We hope you have enjoyed this earthcache and appreciate the efforts that Gwinnett County Stormwater Management is taking to reduce pollution and improve our water quality.
If you've seen a slimy, brown residue or oily sheen in your local waterway or storm drain, it could be the result of iron bacteria, a naturally occurring microorganism. If you can stir it up with a stick and the sheen separates into chunks, it is most likely iron bacteria. If it breaks apart but then goes back together when you stop stirring, it is most likely oil. Learn more about this bacteria by reading an iron bacteria fact sheet. If you are unsure whether or not you have found a naturally occurring bacteria or a possible pollutant, please report the incident to Gwinnett County's 24-hour reporting hotline at 678.376.7000.