Extreme drought: summary of hydrologic conditions in Georgia, 2011

Abstract

In 2011, new record-low monthly discharge occurred at 52 of 113 streamgages that have 20 or more years of data. These 52 streamgages are located throughout Georgia. Most of the State received lower-than-normal precipitation; from central Georgia to Florida, the State received 50-75 percent of normal precipitation. Normal is defined as a 30-year average for 1971-2000. New record-low 7-day average discharge occurred at 24 of 113 streamgages that have 20 or more years of data in 2011. The majority of these streamgages were located in southern Georgia. These maps represent hydrologic conditions during the 2011 WY compared to available historical data. The colors represent runoff (flow per unit area) as a percentile of long-term averages. Runoff was calculated for each basin and assumed to be uniform over the entire basin area. Only streamflow stations with a complete daily-flow dataset for the 2011 WY were used (U.S. Geological Survey, 2012c). For the first quarter of the 2011 WY (October-December 2010), much of the State was observing "below normal" and "much below normal" runoff conditions as a result of extreme temperatures and lack of precipitation during the preceding summer months of the 2010 WY (A). Little to no precipitation kept the majority of the State in drought during the second and third quarter of the 2011 WY (B, C). After receiving 50-75 percent of normal precipitation from central Georgia to Florida during the 2011 WY, the majority of the State was in an extreme drought during the fourth quarter as runoff was "much below normal," and large areas of the State observed some of the lowest runoff conditions on record (D).

High secondary production in a Coastal Plain river is dominated by snag invertebrates and fuelled mainly by amorphous detritus

“…Unfortunately, the Ogeechee River is no longer in reference condition, a pollution incident in 2011 causing the deaths of ~38 000 fish over >100 km of river (http://www.georgiaconservancy.org/coast/fishkill.html; Georgia Department of Natural Resources, ; Knaak, Frantz & Peck, ). Our findings should serve as a benchmark for monitoring recovery of the Ogeechee and other Coastal Plain rivers subjected to human impacts.…”

Selected low-flow frequency statistics for continuous-record streamgages in Georgia, 2013

“…In addition, 40 or more of the 197 streamgages have significant negative trends in the monthly minimum 1-day and 7-day average flows for the months of April through November. Multiple droughts have occurred in Georgia since 1998 (Barber and Stamey, 2000;Knaak and others, 2009Knaak and others, , 2010Knaak and others, , 2013Knaak and Peck, 2014). Most of the streamgages with significant negative trends have a period of record that ends during one of the recent droughts, particularly those streamgages with record through the 2013 climatic year.…”