USGS Georgia Water Science Center E-News

September flooding and E. coli bacteria sampling

Oct. 1, 2009

Indicator bacteria levels in the Chattahoochee River increased substantially during and after the epic flooding that struck Atlanta on September 22-23, 2009. On September 14, 2009, the Upper Chattahoochee Riverkeeper collected water samples from the Chattahoochee River at West Paces Ferry Road in Vinings that contained an Escherichia coli (E. coli) bacteria density of 75 most probable number per 100 mL. Multiple water samples collected from the river at West Paces Ferry Road by the USGS on September 23, 2009 were nearly 200 times higher than the value measured on September 14, 2009. The USGS sampled three additional sites downstream from Vinings on September 23, 2009.

Sample date  / Location  / E. coli density (most probable number per 100 mL)

9/14/2009 Chattahoochee River at West Paces Ferry Rd   75

9/23/2009 Chattahoochee River at West Paces Ferry Rd   14,000

9/23/2009 Chattahoochee River at Interstate 20   18,000

9/23/2009 Chattahoochee River at Fairburn, GA   3,900

9/23/2009 Chattahoochee River at Whitesburg, GA   1,100

The National Park Service and the Upper Chattahoochee Riverkeeper collected water samples from the Chattahoochee River and Big Creek on September 28 and 30, 2009. These values show substantial decreases in E. coli density within 7 days of the flood.

Sample date  / Location  / E. coli density (most probable number per 100 mL)

———————————————————————————————————————

9/28/2009 Chattahoochee River at Medlock Bridge Rd near Norcross  370

9/28/2009 Chattahoochee River at Roswell Road   1,420

9/28/2009 Chattahoochee River at Johnson Ferry Rd   785

9/28/2009 Chattahoochee River at West Paces Ferry Rd   760

9/30/2009 Big Creek at Roswell Mill   170

9/30/2009 Big Creek at Riverside Park 130

9/30/2009 Chattahoochee River at Johnson Ferry Rd 140

9/30/2009 Chattahoochee River at South Cobb Dr.  >24,196

For more information about USGS activities in Georgia, please visit http://ga.water.usgs.gov/.

Another good reason for Green Infrastructure!