An Investigation into the 2012 drought on Apalachicola River Steve Leitman, Bill Pine and Greg Kiker
Apalachicola-Chattahoochee-Flint (ACF) River basin 20,400 sq. mi. One of the most actively disputed river basins in the U.S. Lies in Alabama (12.5%), Florida (12.5%), and Georgia (75%) No agreement on the allocation of water resources Average annual precipitation in the basin 55 Evapotranspiration about 32-42 annually Average annual runoff 15-40
Apalachicola-Chattahoochee-Flint River basin Chattahoochee 13 dams, multi-purpose operations. Three large storage reservoirs operated by Corps, other dams have limited to no storage capacity. Lake Lanier largest reservoir and provides municipal water supply for Atlanta region. Flint 2 dams, no storage capacity Lake Blackshear largest Very large ag interests, surface and groundwater water withdrawals.
THE APALACHICOLA RIVER
. Apalachicola River River begins at the confluence of Chattahoochee and Flint Rivers. Most biologically diverse river ecosystem in the east. Flow in river defined by rainfall and water management in Georgia and Alabama, not local conditions. Jim Woodruff Dam Navigation, recreation Minimal storage capacity Head limit problems effect operation No fish passage Minimum flow 5000 CFS Influenced by upstream storage Apalachicola River 106 miles from dam to Apalachicola estuary 40 ft elevation change Large floodplain Average daily stream flow about 20,000 cfs at Jim Woodruff inflow and 23,600 cfs at Sumatra gage (1977 2013) 5000-~200,000 CFS River width few hundred feet to 4.5 miles
Bluff at Estiffanulga (NM 63)
Big river, small reservoirs About 1.2 million ac-ft active reservoir storage ~66% of storage in Lake Lanier (headwaters) Perception that reservoir operations have large impacts on downstream flows Reductions in downstream flows impacting coastal resources? Atlanta is stealing all of our water
ELEVATION IN FEET 1200 1000 BUFORD DAM (Lake Sidney Lanier) PROFILE APALACHICOLA AND CHATTAHOOCHEE RIVERS 800 600 Atlanta, GA WEST POINT LAKE Head of Navigation 400 400 200 0 CHATTAHOOCHEE RIVER Columbus, GA WALTER F. GEORGE L&D 200 GEORGE W. ANDREWS L&D JIM WOODRUFF L&D 0 APALACHICOLA RIVER 500 400 300 200 100 0 MILES
2011 2012 drought
Simple question. In 2012, could ACF reservoirs have been operated in a manner to restore Apalachicola River flows to levels that would have protected the Apalachicola estuary?
Simple question. In 2012, could ACF reservoirs have been operated in a manner to restore Apalachicola River flows to levels that would have protected the Apalachicola estuary? If YES Then reservoirs could be used to augment flows to Apalachicola River and Bay during extreme drought conditions. A simple intuitive solution to the complex issue related to freshwater inflows to Apalachicola Bay.
Simple question. In 2012, could ACF reservoirs have been operated in a manner to restore Apalachicola River flows to levels that would have protected the Apalachicola estuary? If YES Then reservoirs could be used to augment flows to Apalachicola River and Bay during extreme drought conditions. A simple intuitive solution to the complex issue related to freshwater flows to Apalachicola Bay. If NO By eliminating the simple, intuitive solution more holistic options need to be conceived.
2012 conditions in the ACF basin...
Drought Conditions 2012 Rainfall deficits 8-18 inches in the basin (15% 33% below average) Record low ground water levels Driest region in the country (2011 2012) River flow lowest on period of record (1922 2013)
2012 conditions in Apalachicola... Record low river flows in 2012 (and several of preceding years)
2012 conditions in Apalachicola... Record low river flows in 2012 (and several of preceding years)
2012 conditions in Apalachicola Bay... High salinities and high temperatures
Simple question. Could reservoir releases increase Apalachicola River discharge, lower salinity in Apalachicola Bay, ultimately benefiting oyster populations?
Simple question. Could reservoir releases increase Apalachicola River discharge, lower salinity in Apalachicola Bay, ultimately benefiting oyster populations? We are not sure about the last part, but we can answer the first part
Methods Results are based on a simple accounting of flow deficits and storage available in the basin. At the beginning of 2012, reservoir storage in the ACF basin was not at full capacity and Corps was operating the reservoirs under emergency drought provision measures. By the current reservoir operating plan, emergency drought provision measures are not lifted until the reservoirs are nearly refilled.
All Values in Feet Above Mean Sea Level 1075.0 Lanier Elevations: 2011-2012 TOP OF POOL 1070.0 1065.0 TOP OF ZONE 2 TOP OF ZONE 3 1060.0 1055.0 1050.0 1045.0 1040.0 1035.0 TOP OF ZONE 4 2011 elevations 2012 elevations Initial Impact Level Recreation Impact Level Water Access Limited Level Bottom of Conservation Pool 1030.0 Jan Jan Mar Apr May May Jun Jul Aug Sep Oct Nov Dec
All Values in Feet Above Mean Sea Level 640.0 West Point Elevations: 2011-2012 635.0 630.0 625.0 2011 elevations 2012 elevations Initial Impact Level Recreation Impact Level Water Access Impact Level Bottom of Conservation Pool 620.0 615.0 1/1 1/31 3/1 3/31 4/30 5/30 6/29 7/29 8/28 9/27 10/27 11/26 12/26
Jan Jan Jan Feb Feb Mar Mar Apr Apr May May Jun Jun Jul Jul Jul Aug Aug Sep Sep Oct Oct Nov Nov Dec Dec Dec All Values in Feet Above Mean Sea Level 192.0 W.F. George elevations: 2011-2012 190.0 188.0 186.0 2011 elevations 2012 elevations Initial Impact Level Recreation Impact Level Water Access Limited Level Bottom of Conservation Pool 184.0 182.0
Methods The average inflow from the Flint River to Lake Seminole for 2012 was 2,583 cfs, by far the lowest average ever in the period of record. When this average value is compared to the next lowest value in the period of record (2011), it is more than 1,000 cfs less than that year. To put the volume of this deficit in context, nearly half of the total storage capacity of the entire ACF reservoir system would have to be released to make inflow to Lake Seminole from the Flint basin for the 2011 and 2012 comparable.
Methods To further put this deficit into context, the total average annual consumptive withdrawals from the Flint and Chattahoochee Rivers above Jim Woodruff Dam was about 1,250 cfs in 2008. The net average annual municipal and industrial demands were about 750 cfs and the average annual agricultural irrigation demand effect on stream flow was about 500 cfs. The average annual withdrawal from the Chattahoochee basin was about 650 cfs and from the Flint basin about 600 cfs.
Flow (cfs) 15000 Bainbridge flow (1939-2012) 12000 9000 6000 2011 2012 MEDIAN 75% EXCEEDED 90% EXCEEDED 95% EXCEEDED 3000 0 Jan Jan Feb Mar Mar Apr May May Jun Jul Jul Aug Sep Oct Oct Nov Dec Dec
Methods Average outflow from JW Dam in 2012 = 7,600 cfs. In the 90 year period of record for at Chattahoochee, Florida, average annual flows at this location were below 10,000 cfs in only three other years (2000, 2007 and 2011). The next lowest flow was > 9,300 cfs. The 1000 cfs + deficit from the Flint was only part of the problem, flows were also depressed on the Chattahoochee side of the basin.
Flow (cfs) 15000 Jim Woodruff outflow (1922-2012) 12000 9000 6000 3000 0 Jan Jan Feb Mar Mar Apr May May Jun Jul Jul Aug Sep Oct Oct Nov Dec Dec
Methods The amount of additional augmentation from the ACF reservoir system to make 2012 releases comparable to the next lowest year in the 90 year period of record would require releasing more than ¾ of the total storage capacity of the reservoir system. And, this would be required in a year where there was very limited refilling of the reservoirs, the volume of water in storage was already depressed from full storage and at a time the length of the drought was not known.
Flow (cfs) 40000 Sumatra flow (1978-2012) 35000 30000 25000 20000 15000 2011 2012 MEDIAN 75% EXCEEDED 90% EXCEEDED 95% EXCEEDED 10000 5000 0 Jan Jan Feb Mar Mar Apr May May Jun Jul Jul Aug Sep Oct Oct Nov Dec Dec
In summation, it is apparent that it would not have been possible to manage the federal storage reservoirs in a different manner to have increased Apalachicola River flows to median levels during 2012.
The fundamental issue in the ACF basin remains small storage capacity relative to large river discharge. Small storage capacity limits the ability to manage our ways out of climate related droughts. It does not seem that all of our problems can be solved by simply being better managers managing our way out of frequent drought will at best be extremely challenging.
Another interesting question relating to the 2012 drought is whether this event is an anomaly and the flow data in the period of record (1922 2013) is what can be expected in the future? Or,is flow data in the period of record the anomaly and the 2011 2012 drought a portent of what should be expected in the future?
Recent research into long-term climate data suggests that over the past 500 years there have been multiple droughts which are both longer and more severe and that the past 50 60 years have had the least number of severe drought than any period in the last 500 years. This information further stresses the need to re-think our approaches to management problems in the ACF basin.
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