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A summary of drought conditions based on the
Apalachicola-Chattahoochee-Flint River Basin
Drought Assessment Webinar on
May 30, 2017
Auburn University Water Resources Center and the National Integrated Drought Information System (NIDIS)
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Drought conditions in the ACF Basin have continued to improve except for lingering moderate drought to severe drought in the most northern tip of the basin and parts of the southern portion of the basin, according to the most current US Drought Monitor (as of 5/23/2017). Note, the Southeast continues to be the only area in the United States that currently has areas of Extreme Drought.
Please share the following highlights of the recent NIDIS ACF Drought Assessment Webinar with others who might be interested.
Our next briefing will be Tuesday, June 13, 2017, 1 pm ET.
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Current Drought Status
Drought conditions in the ACF Basin have continued to improve except for lingering moderate drought to severe drought in the most northern tip of the basin and parts of the southern portion of the basin, according to the most current US Drought Monitor (as of 5/23/2017).
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Rainfall Deficits over the past 90 days
Rainfall deficits over the past 90 days have improved over the past few weeks, though parts of south Georgia, southeast Alabama and Florida still have significant deficits.
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Official NOAA 3-Month Outlook
According to the most recent NOAA 3-month Precipitation Probability Outlook, most of the southeastern U.S. has an equal probability of above-normal, normal, and below-normal (white areas - not changed since last briefing).
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U.S. Drought Monitor
According to the most recent U.S Seasonal Drought Outlook, forecasted drought conditions in most of Georgia, Alabama and Florida have improved significantly over the past several weeks, with central Georgia the main area forecasted for drought to persist.
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Realtime Streamflow
Realtime streamflows have recovered for the most part in Alabama and the northern half of Georgia, but many streams are below-normal to much-below-normal in the far-south of Georgia and north to central Florida.
(
http://waterwatch.usgs.gov
).
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Flint River at Albany Streamflow
Streamflow for the Flint River at Albany has recovered in recent weeks to the normal range, with similar trends at Griffin, Carsonville and Bainbridge though they remain in the upper reaches of the below-normal range (see
http://waterwatch.usgs.gov
).
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Groundwater Conditions
Previous Brief: Current Brief:
Groundwater conditions have generally remained about the same over the past few weeks, with wells ranging from normal to low in the ACF Basin (
http://waterwatch.usgs.gov
).
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One Month Mean Daily Streamflow Forcast
The 1-Month Mean Daily Streamflow forecast from the Southeast River Forecast Center favors slightly below-normal flows for the Chattahoochee and Apalachicola rivers, and near -normal flows for the Flint River for the next month.
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Due to persistent drought conditions in the upper ACF Basin, Lake Lanier remains in Zone 4, though levels have shown recent improvements, and is forecasted to stay in Zone 4 (dashed line) for the next few weeks.
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ACF Basin Composite Conservation and Flood Storage
The ACF System Conservation Storage has risen in recent weeks to Zone 1 and is forecasted to remain in Zone 1 (orange line) for the next few weeks.
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Drought Assessment Webinar Summary
*
Drought continues to improve in the ACF Basin, which has an area of only 23% in D1 or greater.
*An a
ctive wildfire season continues in central Florida.
*The upper and middle ACF Basin received
3
to 6 inches of rainfall in the past two weeks.
*
There is now a rainfall surplus over the upper and middle ACF Basin at 90 days, while the lower ACF is still running a
deficit.
*The
7-day forecast favors 2-3 inches over the upper ACF, lesser amounts for the middle and lower basin.
*
Neutral conditions persist in the tropical Pacific, hovering near the +0.5 C threshold.
*
Neutral now equally likely, El Nino chances have dropped to under 50%.
*
NOAA seasonal forecast favors warm spring/summer and equal chances for above-normal/normal/below-normal rainfall.
*
Florida's rainy season has begun by some measures.
*
Real-time
streamflows
in the ACF Basin range from much-above-normal to much-below-normal.
*
28-day average streamflow for the Chattahoochee River at Cornelia, and Chestatee River at Dahlonega are currently at the below-normal range.
*
28-day average streamflows for the Chattahoochee River below Lake Lanier are in the below-normal to much-below-normal range.
*
28-day average streamflows for the Flint River currently range from normal, to below-normal range
.
*
Groundwater levels range from low to normal across the ACF Basin.
*The Southeast River Forecast Center's 1 month and 3 month streamflow forecasts favor slightly below-normal flows for the Chattahoochee and Apalachicola rivers, and near-normal flows for the Flint River. Note, streamflow forecast pie charts do not directly include any adjustments to the ESP forecast based on ENSO, CPC or other factors, but are based on soil conditions relative to normal in concert with historical precipitation.
*
Significant rain across the ACF region has reduced the short-term crop stress significantly,
derived from the UAH Cumulative Water Stress Index.
*
Mid-term crop stress is also reduced by the recent rainfall.
*
Long-term crop stress is still significant.
*Record-setting drought conditions across Alabama last fall have been largely eliminated due to sustained and above average rainfall, including record-setting May events.
*Some streamflows in Alabama remain at below-normal levels.
*Alabama is monitoring groundwater levels to assess recharge impacts.
*All Alabama reservoir levels are at normal levels.
*The most significant remaining impacts in Alabama are to the agricultural sector - forest pine beetle infestation and cover crop/hay planting (minimal in the ACF Basin).
*
West Point and Walter F. George reservoirs are above or near their guide curves.
*
Buford still remains in Zone 4 and is forecasted to rise slightly over the next few weeks.
*
Continuing to meet downstream minimum flow requirements.
*
The ACF System Conservation Storage is in Zone 1 and is forecasted to remain there over the next few weeks.
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Acknowledgments and Resources:
- David Zierden, FSU
- Paul Anckorn, USGS
- Todd Hamill, SERFC
- Cameron Handyside, UAH
- Tom Littlepage, AL OWR
- Cynthia Donald, US ACE
Summary prepared by Eric Reutebuch, Auburn University
General drought information
General climate and El Niño information
Streamflow monitoring & forecasting
Groundwater monitoring
Additional information can be found at the Southeast River Forecast Center's Water Resources Outlook:
Experimental Long-Range River Flood Risk
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