June ACF Basin Drought & Water Update

ACF Drought and Water Update

June 22, 2021

A Summary of Drought Conditions from the:

Apalachicola-Chattahoochee-Flint (ACF) River Basin Drought and Water Monthly Webinar

The ACF Basin is drought-free according to the most current U.S. Drought Monitor (data as of 6/17/2021).

Webinar summary and recording can be found on the new drought.gov here.

Next month’s ACF Drought and Water Webinar is on Tuesday, July 27, 2021 at 1:00pm ET.

June Key Points

ACF Climate Conditions and Outlooks

Tropical Storm Claudette impacted all areas of the ACF, from heavy rainfall to severe weather
Abnormally dry conditions rapidly improving across North Florida, the rest of the ACF remains drought free.
Above normal rainfall over the ACF the past 30 and 90 days
Troughing and sagging frontal boundary to continue bringing rainfall to the northern Gulf Coast, possibly persistent for week 2
Neutral conditions in the Pacific, 50% chance of La Nina returning this fall
CPC seasonal forecast favors above normal temperatures, leans towards above normal rainfall
NOAA hurricane forecast calls for 60% chance of above normal year, less active than record-setting 2020
Rainy season has begun for all of Florida, hydrology of the ACF in good shape!
State of Alabama - The AL Drought Declaration was updated on 5/11/21 to reflect improved conditions. No reported water availability issues. Alabama Drought Monitoring and Impact Group (MIG) will meet on 7/13/2021 at 1pm (CT) via WebEx.

Real-Time Streamflow & Forecasts

Real-time streamflow in the ACF basin are currently in the much above normal to much below range.
The below normal 7-day average streamflow indicates that the ACF basin is hydrologically drought free.
28-day average streamflow for the Chattahoochee River are currently in the above normal to normal range.
28-day average streamflow for the Flint River are currently in the normal range.
Real-time groundwater levels at well i.d. 08G001 and 11K003 are currently ranked normal and above normal range, respectively.
No flooding expected in the next 10 days
SERFC 1 month streamflow forecast - near normal (Claudette helped reverse decreasing trend in Flint and Apalachicola)
SERFC 3 month streamflow forecast - near normal

ACF Basin Reservoir Conditions

Inflows into the projects are normal with this past rain event.
Currently, all projects except Buford are above top of conservation.
Lake Lanier, West Point, and WF George are currently in Zone 1. Lake Lanier/Buford Dam is continuing to fill to top of conservation.
Water management is prepared to go to flood surcharge operations if needed.
The ACF system conservation storage is in Zone 1 and is forecasted to remain in Zone 1 for the next few weeks.

Apalachicola Bay Daily Average Salinity Levels

Cat Point salinity values experienced a large increase mid-May and peaked on May 22. Value then decreased and are within the 25-75th percentile range as of June 9.
Dry Bar salinity values fluctuated in May through the beginning of June. Values are within the 10-24th percentile range as of June 9.
East Bay Bottom salinity values followed a similar pattern to Cat Point's with a large spike observed on May 22. Values have gradually decreased into June.

Special Presentation: The Evaporative Demand Drought Index (EDDI) in the Southeast/ACF DEWS Region

Mike Hobbins

Univ. of Colorado-Coop. Inst. for Research in Environmental Sciences, Boulder, CO& NOAA-Physical Sciences Laboratory

EDDI webpage:https://psl.noaa.gov/eddi/

>40-year downloadable archives of CONUS-wide EDDI:

https://downloads.psl.noaa.gov/Projects/EDDI/CONUS_archive/

Daily map and data access for SE DEWS region:

https://downloads.psl.noaa.gov/Public/mhobbins/EDDI/SE_DEWS/

Off-site hosting:

| Drought.gov | NIDIS DEWS pages | RISA and RCC climate dashboards

Current Drought Status

According to the most current U.S. Drought Monitor (data as of 6/15/2020).

0% of the ACF Basin is in drought

0% of Alabama in D0

9.2% of Georgia in D0

40.8% of Florida in D0

9.7% of Florida in D1

Lawn and Garden Moisture Index

June 21, 2021's Lawn and Garden Index from the University of Alabama at Huntsville displays expansive areas of wetness across the vast majority of the ACF, with a small pocket of dry in South GA.

Rainfall Totals & Departures

30-Day Precipitation Totals

The past 30 days, saw above normal rainfall totals of 6-8 inches in most of the ACF and areas in the lower ACF with >10 inches, largely due to TS Claudette.

90-Day Precipitation Departures

90-day rainfall departures show most of the ACF has experienced above normal rainfall with a bit of remaining dryness in north FL and south GA.

NOAA 3 Month Outlook (June-Aug)

The NOAA 3-month Seasonal Outlook (July-Sep) predicts an equal chance of below normal, normal, or above-normal temperatures and increased chances of above-normal rainfall.

Real-time Streamflow

Real-time streamflow in the ACF basin are currently in the much above normal to much below range.

(http://waterwatch.usgs.gov)

Chattahoochee River near Whitesburg

28-Day Average Streamflows

28-day average streamflow for the Chattahoochee River are in the above normal to normal range, 28-day average streamflow for the Flint River are in the normal range, and the Apalachicola River flows are in the normal range.

(for more info: http://waterwatch.usgs.gov)

Real-Time Groundwater Conditions

Real-time groundwater levels across the ACF basin are largely in the normal range. The two reference groundwater wells (Dougherty and Miller Counties, GA) were ranked in the above normal to normal range.

(http://waterwatch.usgs.gov)

ACF Reservoir Conditions

(as of 6/21/2021)

Inflows into the projects are normal due to recent rain events. Currently, all projects, except Buford, are operating above top of conservation. The ACF system conservation storage is in Zone 1 and is forecasted to remain in Zone 1 for the next few weeks.

Apalachicola Bay

Daily Average Salinity Levels

Cat Point (above) and East Bay Bottom salinity experienced a large increase mid-May and peaked on May 22nd. Values then decreased gradually into June.

1-Month & 3-Month Mean Daily Streamflow Forecasts

The 1-month mean daily streamflow forecast predicts near normal flow conditions (Claudette helped reverse decreasing trend in Flint and Apalachicola).