By John Schaffner

David Chastant, the stormwater manager for the city of Sandy Springs, explained to members of the Sandy Springs/Perimeter Chamber of Commerce the importance of the stormwater management program the city recently embarked on by approving $1.6 million to conduct a two-year inventory of the system.

Chastant, who is an employee of CH2M Hill, is overseeing the city’s move to a more proactive approach to the problems of stormwater management instead of a reactive approach. But the first item of business is determining the effectiveness and state of repair of the Sandy Springs system that was put in place by Fulton County.

According to Chastant, there are six watersheds and 59 miles of impaired streams in Sandy Springs; those streams eventually dump into the 22 miles of the Chattahoochee River bordering Sandy Springs. The easiest to identify in Sandy Springs is the Long Island Creek Watershed, which encompasses about 6 square miles leading to the river.

He said more than 80 percent of the pollution of those streams is the result of stormwater runoff, which carries such pollutants as pet wastes, pesticides, motor oil, dirt and soil, among other items. The runoff affects the water quality all along the Chattahoochee.

The more urbanized an area is, the more impervious surfaces exist, the result being proportionally more stormwater runoff. To control the runoff, the city maintains a stormwater system that collects water from roads and directs it through pipes either into the streams or to control facilities, such as detention ponds. The city’s system includes about 4,000 structures and 70 miles of pipes.

Chastant said a present focus is on things such as low-impact development to minimize the amount of impervious surfaces by narrowing the roads, building smaller parking lots and putting the water onto natural areas “so that we can reduce the amount of water going into the streams and the amount of water that we have to treat.”

The main pollutant in Sandy Springs is fecal coliform. The biggest thing you can do is to try to eliminate the sources, which in the case of fecal coliform is wildlife. But that is not the only source, Chastant explained. There are overflows from the sanitary sewer system and from septic systems.