drought monitoring, prediction and response - a view from georgia -

Drought Monitoring, Prediction and Response- A View From Georgia -David Emory Stooksbury, Ph.D.

State Climatologist and Associate Professor

Engineering and Atmospheric SciencesCollege of Agricultural & Environmental Sciences

The University of Georgiastooks@engr.uga.edu

Facts About Georgia◊ In 1960 Atlanta’s population: 1 million◊ In 1960 Georgia’s population: 4.3 million

◊ In 2008 Atlanta’s population: 4.5 million◊ In 2008 Georgia’s population: 8.5+ million

◊ Largest state east of the Mississippi River◊ 8th largest state in population

Facts About Georgia◊ Northern quarter is southern highlands◊ Southern half is the coastal plain◊ Most of the population lives in the piedmont

◊ The fall line bisects the state (Montgomery, Columbus, Macon, Augusta, Columbia, Raleigh, Richmond and Georgetown)

Georgia Water Facts ◊ North of the fall line - primarily surface water

• Drainage basin for Lake Lanier 1040 sq. miles.

◊ South of the fall line - primarily ground water

◊ 1.5 million acres under irrigation, primarily in southwest Georgia

Georgia Climate Facts◊ Rule of Thumb: 50 inches of rain per year

• More than 80 inches in the mountains• 45 inches interior southeast

◊ Rain is more or less evenly distributed over the year: March 5 inches and October 3.5 inches

◊ Evapotranspiration is extremely important in drought forecasting

GEORGIA DROUGHT MANAGEMENT PLAN

1) DROUGHT DECLARATION PROCESS2) AGENCIES and ORGANIZATIONS3) PRE-DROUGHT STRATEGIES4) DROUGHT RESPONSES5) DROUGHT INDICATORS and TRIGGERS6) CLIMATE DIVISIONS MAP

Approved: March 26, 2003

Section 1) DROUGHT DECLARATION PROCESS

The following is the process for declaring drought conditions and responses:

1A): The State Climatologist’s office and EPD will routinely monitor and evaluate stream flows, lake levels, precipitation, groundwater levels, and other climatic indicators that are supplied by several cooperating entities …

Precipitation◊ 30 days◊ 90 days◊ 6 months◊ 12 months◊ Water Year◊ 24 months◊ 36 months

30 Day Precipitation

90 Day Precipitation

6 Month Precipitation

12 Month Precipitation

Water Year Precipitation

24 Month Precipitation

36 Month Precipitation

Soil Moisture

“Top” Soil Moisture (top 1 meter)

“Deep” Soil Moisture (2 meters)

Stream Flows

Stream Flows

Stream Flows

Lake Russell GA/SC

Clarks Hill Lake GA/SC

Lake Hartwell GA/SC

Lake Lanier GA

Groundwater

Drought Level GuidanceCD Drought Indicators

1 SPI-3, SPI-6, SPI-12 Lake AllatoonaChattooga River at Summerville

2 SPI-3, SPI-6, SPI-12 Lake Lanier, Lake Allatoona Etowah River at Canton Chestatee River near Dahlonega

Georgia Drought Response Levels◊ Level One: Water on scheduled days - 12 midnight to

10 a.m - and - 4 p.m. to 12 midnight.

◊ Level Two: Water on scheduled days - 12 midnight to 10 a.m.

◊ Level Three: Water on scheduled weekend day - 12 midnight to 10 a.m.

◊ Level Four: Complete outdoor water use ban

Determining Drought Level Response

◊ Look at climatological data

◊ Look at triggers guidance

◊ Discussion

Comments about Discussion◊ Drought impacts are cumulative - data may not

capture the essence of the drought

◊ Drought varies over time and space - part of the state may be in short-term drought while other parts are in long-term - the importance various indicators will vary from drought to drought and within a drought.

◊ Seasonal components are important as well antecedent conditions such as soil moisture, stream flows, reservoir levels

Determining when to relax restrictions

◊ Look at climatological data

◊ Look at trigger guidance

◊ Look at climate outlooks

◊ Discussion

Drought Outlooks◊ CPC Seasonal Outlooks

◊ IRI 3-month Outlooks

◊ NOAA’s and IRI’s ENSO Outlooks

◊ Southeast Climate Consortium’s Outlooks - State Climatologists of AL, FL, GA and NC - La Nina Watch issued in September 2007

Additional Information◊ State Drought Page: www.georgiadrought.org

◊ UGA Automated Weather Stations: www.georgiaweather.net

◊ Southeast Climate Consortium: www.agroclimate.org