For my final presentation in my Hydrology class, I created a Drought Vulnerability Model for the state of Georgia. In measuring the potential for drought, we can have actionable prevention and responsible water usage changes. Taking into factor, precipitation, temperature, crop water consumption, ground water wells, land use, slope, soil type and geology of Georgia, we can effectively model potential areas in Georgia that would be vulnerable for drought.

1. DROUGHT VULNERABILITY
MODELING FOR GEORGIA
COMPLETED BY: REBECCA PEOPLES
IN ASSOCIATION WITH DR. SUDHANSHU PANDA
HYDROLOGY ESCI 4003K
UNIVERSITY OF NORTH GEORGIA | INSTITUTE FOR ENVIRONMENTAL SPATIAL ANALYSIS

2. OVERVIEW
• Introduction
• Purpose of Modeling
• Overview of Methods
• Methodology
• Prior Reclassification
• Reclassification
• Weighing
• Results
• After Reclassification
• Total Drought Vulnerability Model
• Analysis
• Future Recommendations
• Real-Time Drought Monitoring
• Sources
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(Rippey, B)

3. INTRODUCTION
• Dictionary Definition of Drought: (noun) a prolonged period of
scanty rainfall 1
• As Hydrologists, we know that multiple factors impact the likelihood of
drought, including:
• Precipitation
• Temperature
• Land Cover
• Soils
• Slope
• Social Impact
• Agricultural Misuse
• Multiple Other Factors
3
1 (The Definition of Drought)

4. INTRODUCTION (CONT)
• Droughts are currently impacting:
•20.8% of the population
•102.4 million people
•in the lower 48 states
4
2 (Where is Drought This Week)

5. INTRODUCTION (CONT)
• History of Drought in GA:
• 1903-1905 “Earliest Recorded Severe Drought in Georgia”
• 1924-1927 Coined the “Drought of the Century” (DoC) largely impacted agriculture
• 1930-1935 Coined DoC, largely impacted agriculture and surrounding states
• 1938-1944 Recurrence interval exceeded 50 years
• 1950-1957 Coined DoC, Recurrence interval exceeded 25 years
• 1976-1978 Federal disaster declared
• 1980-1982 Lowest streamflows ever recorded, lowest reservoir retention at Lake Lanier
• 1985-1989 Coined DoC, had been the warmest year up to that date, recurrence interval of 50-100
years
• 1988-2003 Coined DoC, Statewide restrictions on water usage, lowest stream flows
• 2006-2007 Coined DoC, said to be worse than the drought in the 50’s 5
3 (Dolan, M. H)
“DROUGHT OF THE
CENTURY”
COUNT: 6

6. INTRODUCTION (CONT)
• Types of Droughts
• Meteorological
• Agricultural
• Hydrological
• Socio-Economic-Political
Today’s Focus – Summary of
all factors creating a
generalized drought period 6
4 (WMO)

7. PURPOSE OF MODELING
• Creation of Recurrence Intervals => Prediction
• Prevention
• Monitoring
• Reserves
• Change for the Future
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8. OVERVIEW OF METHODS
• Download all data
• Project/Georectify all data to be in the same projection
• Create rasters from features as needed
• Reclassify the raster in level of severity in causation to droughts
• 1=Least Likely to Result in Drought
• 10=Most Likely to Result in Drought
• Perform a weighted sum to the reclassifications
8

9. OVERVIEW (CONT.)
9
Dowload Data Open ArcMap Create Model Edit Model Edit Workspace - Set Output
Create GA Boundary Shape
File
Mosaic the 26 Elevation
Rasters
Calculate Slope of DEM
Extract by Mask the
DEMSlope
Use Times tool to get in
meters
Feature to Raster the Precip
Data (PrecipInches)
Perform Cell Statistics to get
Avg Temp Raster
Feature to Raster the
Geology (Rock Type)
Project to Raster to
Georectify the NLCD raster
Create Feature to Rasters
STATSGO (Drainage,
HydGro, PermH, Texture)
Combine Crop Frequency Extract by Mask Crop Freq Clip Well Data
Reclassify based off of data
tables below
Apply weighted Sum (based
off of data table below) to
Reclassified Rasters

10. METHODOLOGY PRIOR
RECLASSIFICATION
• Download data, place in the Input folder
• Create an Output folder
• Create a Model
• Set up in the Workspace for creations to
automatically send to the specified folders
• Add downloaded data to the map
• Create a Georgia Boundary file by dissolving
the State feature in County shapefile 10

11. METHODOLOGY (CONT)
• Mosaic the 26 Elevation Rasters to
create the Digital Elevation Model
• Calculate Slope as Percent Rise
• Extract by Mask the Slope Raster using
the GA boundary shapefile
• Use the Times tool to get the slope in
meters
11

12. METHODOLOGY (CONT)
Using the 1981-2010
Precipitation data
• Feature to Raster field
PrecipInches
12

13. METHODOLOGY (CONT)
Using both the Temp
Min and Temp Max for
the years 1981-2010,
we will need to
perform
• Cell Statistics to
calculate the Average
Temp for the areas 13

14. METHODOLOGY (CONT)
Using the Geology Feature,
Rock Type
• Convert the Feature to
Raster
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15. METHODOLOGY (CONT)
Using the NLCD data
• We will need to Project the
Raster to match our other
datums
15

16. METHODOLOGY (CONT)
Using Statsgo Data:
• Create Features to Rasters for the Following
• Drainage
• Hydrologic Group
• Permeability High
• Soil Texture
16

17. METHODOLOGY (CONT)
Using Crop Frequency Data
• Combine
• Extract by mask
Using Well Data
• Clip for data frame
17

18. METHODOLOGY RECLASSIFYING
Reclassify All Raster Data using the
following tables
18
5 (www.exceltoxl.com)

19. METHODOLOGY (CONT)
19
Reclassifying
Avg Temp Scale
49.298004150390625-53.959999084472656 1
53.959999084472656-56.768001556396484 2
56.768001556396484-58.982002258300781 3
58.982002258300781-60.746002197265625 4
60.746002197265625-62.294002532958984 5
62.294002532958984-63.797004699707031 6
63.797004699707031-65.210006713867188 7
65.210006713867188-66.514999389648437 8
66.514999389648437-68.873001098632813 9
Precipitation Scale
43-47 9
47-50 8
50-53 7
53-57 3
57-62 3
62-68 3
68-73 2
73-78 0
78-86 0
Slope Scale
0-0.795747 9
0.795747-2.121991 8
2.121991-3.978733 7
3.978733-6.100724 6
6.100724-8.753213 5
8.753213-11.670951 4
11.670951-15.119186 3
15.119186-19.893666 2
19.893666-67.638466 1
Geology Scale Geology Scale
Metasedimentary Rock 3 Granite 1
Schist 2 Amphibole Shist 2
Grantic Gneiss 2 Mylonite 2
Gneiss 2 Felsic Metavolcanic Rock 1
Ultramafic Intrusive Rock 2 Metavolcanic Rock 1
Biotite Gneiss 2 Gabbro 2
Quartzite 2 Mafic Metavolcanic Rock 2
Mica Schist 2 Syenite 1
Slate 2 Sand 4
Limestone 3 Mafic Gneiss 2
Shale 3 Alluvium 1
Dolostone 3 Clay or Mud 3
Conglomerates 2 Hornfells 2
Phylite 3 Chrnockte 2
Sandstone 3 Dune Sand 4
Amphibolite 3 Unconsolidated Deposit 2
Water 1 Beach Sand 4
Biotite Schist 2
Chert 3
Marble 2
Land Use Scale
11 Open Water 0
21 Developed, Open Space 0
22 Devoloped, Low Intensity 6
23 Devoloped, Medium Intensity 7
24 Developed, High Intensity 8
31 Barren Land 9
41 Deciduous Forest 7
42 Evergreen Forest 2
43 Mixed Forest 5
52 Shrub 2
71 Grassland 5
81 Pasture 6
82 Cultivated Crops 9
90 Woody Wetlands 2
95 Emergent Herbaceous Wetlands 4

20. METHODOLOGY (CONT)
20
Soil Drainage Scale
W Well 4
MW Moderately Well 3
SE Somewhat Exceptional 5
SP Somewhat Poorly 2
P Poorly 1
E Exceptional 6
VP Very Poorly 0
Hydrologic Group Scale
B 5
C 3
D 1
A 7
C/D 2
B/D 4
A/D 6
Soil Permiability Scale
0 1
0.2 3
0.6 3
2 3
6 2
Crop Water Useage Scale
Wheat 6
Corn 1
Cotton 9
Soybean 5
Soil Texture
Class Feature Scale Class Feature Scale
GR-COS Gravelly-coarse sand 28 MUCK muck 14
S Sand 27 MPT Mucky-peat 13
FS Fine sand 26 CB-L Cobbly-loam 12
LS Loamy sand 25 CR-L Cherty-loam 11
LFS Loam fine sand 24 CN-L Channery-loam 10
SL Sandy 23 CR-SIL Cherry-silt loam 9
STV-FSL Very strong fine-sandy loam 22 SIL Silt loam 8
CB-FSL Cobbly-fine sandy loam 21 ST-L Stony-loam 7
ST-SL Stony-fine loam 20 L Loam 6
ST-FSL Stony-fine sandy loam 19 GR-SIL Gravelly-silt loam 5
CR-SL Cherty-silt loam 18 SCL Sandy-clay loam 4
GR-FSL Gravelly-fine sandy loam 17 SICL Silty clay loam 3
FSL Fine sand loam 16 CL Clay loam 2
VFSL Very fine sandy loam 15 UWB Unweathered bedrock 1

21. METHODOLOGY (CONT)
• Some Explanations on the Tables
• LU-More Agriculturally or Industrialized the area, higher drought
possibility
• Soils-Sandy, the higher permeability, higher drought possibility
• Crops-Cotton requires the most amount of water
• Temperature-higher temps, more ET, more drought possibility
• Precipitation-lower averages, higher drought possibility
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22. METHODOLOGY WEIGHTAGE
Using the Weight Sum Tool
• Apply the corresponding weights to each
raster layer, placing more importance on
certain rasters, as they would have a greater
effect on drought probability
22
Weightage
Item Weight(%)
Average Temperature 10
Precipitation 15
Slope 5
Soil Drainage 10
Soil Texture 9
HydrologicGroup 16
Soil Permeability 2
LandUse 30
Geology 3

23. RESULTS AFTER RECLASSIFICATION
Temperature Reclassification
23

24. RESULTS (CONT)
Precipitation Reclassification
24

25. RESULTS (CONT)
Slope Reclassification
25

26. RESULTS (CONT)
Geology Reclassification
26

27. RESULTS (CONT)
Land Use Reclassification
27

28. RESULTS (CONT)
Soil Drainage Reclassification
28

29. RESULTS (CONT)
Hydrologic Group Reclassification
29

30. RESULTS (CONT)
Soil Permeability Reclassification
30

31. RESULTS (CONT)
Soil Texture Reclassification
31

32. RESULTS DROUGHT
VULNERABILITY MODEL
32

33. RESULTS FINAL DROUGHT
VULNERABILITY MODEL OF
GEORGIA
33

34. RESULTS (CONT)
Crop Water Usage Reclassification and Well Location
Overlaying the Drought Vulnerability Model
34

35. ANALYSIS
Based on historical data, the recurrence intervals of drought are
steadily increasing and breaking the molds of how droughts should
be reoccurring. This is both alarming and detrimental to the land and
ground water storage. With the growing socio-agricultural draw
becoming more demanding of the land, it is becoming more
aggravated with lessened precipitation and higher temperatures.
35

36. ANALYSIS (CONT)
As displayed by the adjacent map, places where
we have our crops are at highest risk for
drought. Water management will be vital
especially with the higher water demanding
crop of cotton. In addition the well placements
also lie within the land that is at greatest risk of
drought. Being at a loss of ground water could
have both ecologic and agricultural losses.
36

37. FUTURE RECOMMENDATIONS
• Replace ground water storage after consumption
• Move crops to higher precipitory areas that aren’t at risk
• Conserve water and lessen amount of water misuse or waste
• Move away from higher water consuming plants (ie deciduous) to drought
tolerant plants (ie evergreens)
• Prevent water pollution
• Store water in reservoirs
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38. REAL-TIME DROUGHT MONITORING
See this site for weekly drought
monitoring:
http://droughtmonitor.unl.edu/
US Drought Monitor for the
week of July 26th of 2016 =>
38
(Rippey, B)

39. Questions or
Recommendations?
Thank you for your attention!
Contact Information:
Rebecca Peoples
beccapeoples@gmail.com
(770)330-8117
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40. SOURCES
• Dolan, M. H. (2007, November). A Brief History of Drought in Georgia. Retrieved July 30, 2016, from
http://www.walterreeves.com/uploads/pdf/droughtinhistory.pdf
• Rippey, B. (2016, July 26). U.S. Drought Monitor. Retrieved July 30, 2016, from
http://droughtmonitor.unl.edu/
• The Definition of Drought. (n.d.). Retrieved July 30, 2016, from
http://www.dictionary.com/browse/drought?s=t
• Where is Drought this Week? (2016, July 26). Retrieved July 30, 2016, from
https://www.drought.gov/drought/
• WMO. (2006). Drought Monitoring and Early Warning. Retrieved July 30, 2016, from
http://www.droughtmanagement.info/literature/WMO_drought_monitoring_early_warning_2006.pdf
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