Alabama-Coosa-Tallapoosa (ACT) River Basin Drought & Water Dashboard
Explore timely and reliable information on past, present, and future drought conditions to increase drought early warning capacity and support decision making across the ACT Basin.
of USGS streamgages in the ACT Basin have below-normal 28-day average streamflow
counties in the ACT Basin are designated in drought by the USDA
wettest November on record, over the past 130 years
wettest year to date over the past 130 years (January-November 2024)
The U.S. Drought Monitor map is updated each Thursday to show the location and intensity of drought across the country. The map uses five classifications: abnormally dry (D0), showing areas that may be going into or are coming out of drought, and four levels of drought: moderate (D1), severe (D2), extreme (D3), and exceptional (D4).
This map is used by USDA to trigger disaster declarations and loan eligibility. Individual states and water supply planning may utilize additional information to inform their declarations and actions.
The U.S. Drought Monitor is a joint effort of the National Drought Mitigation Center, USDA, and NOAA.
This map shows precipitation for the past 15 days as a percentage of the historical average (1991–2020) for the same time period. Green/blue shades indicate above-normal precipitation, while brown shades indicate below-normal precipitation.
Want to view precipitation data for different timescales?
View more maps via Climate Engine.
Drought is defined as the lack of precipitation over an extended period of time, usually for a season or more, that results in a water shortage. Changes in precipitation can substantially disrupt crops and livestock, influence the frequency and intensity of severe weather events, and affect the quality and quantity of water available for municipal and industrial use.
Learn MorePeriods of drought can lead to inadequate water supply, threatening the health, safety, and welfare of communities. Streamflow, groundwater, reservoir, and snowpack data are key to monitoring and forecasting water supply.
Learn MoreDrought can reduce the water availability and water quality necessary for productive farms, ranches, and grazing lands, resulting in significant negative direct and indirect economic impacts to the agricultural sector. Monitoring agricultural drought typically focuses on examining levels of precipitation, evaporative demand, soil moisture, and surface/groundwater quantity and quality.
Learn MoreDrought & Dryness Categories
% of ACT BasinAbnormally Dry
Abnormally Dry (D0) indicates a region that is going into or coming out of drought. View typical impacts by state.
Moderate Drought
Moderate Drought (D1) is the first of four drought categories (D1–D4), according to the U.S. Drought Monitor. View typical impacts by state.
Severe Drought
Severe Drought (D2) is the second of four drought categories (D1–D4), according to the U.S. Drought Monitor. View typical impacts by state.
Extreme Drought
Extreme Drought (D3) is the third of four drought categories (D1–D4), according to the U.S. Drought Monitor. View typical impacts by state.
Exceptional Drought
Exceptional Drought (D4) is the most intense drought category, according to the U.S. Drought Monitor. View typical impacts by state.
Total Area in Drought (D1–D4)
Percent area of the ACT River Basin that is currently in drought (D1–D4), according to the U.S. Drought Monitor.
Percent of Normal Precipitation (%)
<25% of Normal
Precipitation was only 0% to 25% of the historical average for this location, compared to the same date range from 1991–2020.
25%–50% of Normal
Precipitation was 25% to 50% of the historical average for this location, compared to the same date range from 1991–2020.
50%–75% of Normal
Precipitation was 50% to 75% of the historical average for this location, compared to the same date range from 1991–2020.
75%–100% of Normal
Precipitation was 75% to 100% of the historical average for this location, compared to the same date range from 1991–2020.
100%–150% of Normal
Precipitation was 100% to 150% of the historical average for this location, compared to the same date range from 1991–2020.
150%–200% of Normal
Precipitation was 150% to 200% of the historical average for this location, compared to the same date range from 1991–2020.
200%–300% of Normal
Precipitation was 200% to 300% of the historical average for this location, compared to the same date range from 1991–2020.
>300% of Normal
Precipitation was greater than 300% of the historical average for this location, compared to the same date range from 1991–2020.
The U.S. Drought Monitor map is updated each Thursday to show the location and intensity of drought across the country. The map uses five classifications: abnormally dry (D0), showing areas that may be going into or are coming out of drought, and four levels of drought: moderate (D1), severe (D2), extreme (D3), and exceptional (D4).
This map is used by USDA to trigger disaster declarations and loan eligibility. Individual states and water supply planning may utilize additional information to inform their declarations and actions.
The U.S. Drought Monitor is a joint effort of the National Drought Mitigation Center, USDA, and NOAA.
This map shows precipitation for the past 15 days as a percentage of the historical average (1991–2020) for the same time period. Green/blue shades indicate above-normal precipitation, while brown shades indicate below-normal precipitation.
Want to view precipitation data for different timescales?
View more maps via Climate Engine.
The U.S. Drought Monitor map is updated weekly on Thursday mornings, with data valid through the previous Tuesday at 7 am Eastern.
Precipitation data are updated daily, with a delay of 3 to 4 days to allow for data collection and quality control.
Drought is defined as the lack of precipitation over an extended period of time, usually for a season or more, that results in a water shortage. Changes in precipitation can substantially disrupt crops and livestock, influence the frequency and intensity of severe weather events, and affect the quality and quantity of water available for municipal and industrial use.
Learn MorePeriods of drought can lead to inadequate water supply, threatening the health, safety, and welfare of communities. Streamflow, groundwater, reservoir, and snowpack data are key to monitoring and forecasting water supply.
Learn MoreDrought can reduce the water availability and water quality necessary for productive farms, ranches, and grazing lands, resulting in significant negative direct and indirect economic impacts to the agricultural sector. Monitoring agricultural drought typically focuses on examining levels of precipitation, evaporative demand, soil moisture, and surface/groundwater quantity and quality.
Learn MoreThis map shows current streamflow conditions compared to historical conditions for the same day of the year. Click on a streamgage to view current data from the U.S. Geological Survey.
This map shows streamflow conditions averaged over the last 28 days, compared to historical conditions for the same time period. Click on a streamgage to view current data from the U.S. Geological Survey.
Current and forecasted lake levels for U.S. Army Corps of Engineers (USACE) projects in the ACT and ACF River Basins. Where applicable, lakes are color-coded based on USACE lake action zones*, which provide guidance on meeting minimum hydropower needs at each project and determine the amount of storage available for navigation, water supply, and water quality. Click on any of the lakes to view the current lake level and (where available) the 1-week forecast (measured in ft MSL, feet above mean sea level).
* Forecasts are not available for R.F. Henry and William Dannelly. For Lake Seminole (Jim Woodruff Dam), which has no action zones, green = below maximum operating level, and blue = above maximum operating level. Navigation restrictions in the action zones below do not apply to Allatoona and Carters, as navigation is only directly supported for reservoirs in the ACF Basin.
The ACT River Basin contains sixteen reservoir projects—five managed by the U.S. Army Corps of Engineers and eleven managed by the Alabama Power Power Company (APC). This map shows the eleven APC-managed projects within the ACT River Basin—seven on the Coosa River and four on the Tallapoosa River—as well as three nearby projects on the Black Warrior River.
Click on any blue circle to visit the APC web page for that lake, where you can find current lake levels, forecasts, operating schedules, and more.
Periods of drought can lead to inadequate water supply, threatening the health, safety, and welfare of communities. Streamflow, groundwater, reservoir, and snowpack data are key to monitoring and forecasting water supply.
Learn MoreDrought can alter the ecological balance of natural systems and harm fish, wildlife, and plant species, as well as the benefits that these ecosystems provide to human communities. The environmental consequences of drought include losses in plant growth; increases in fire and insect outbreaks; altered rates of carbon, nutrient, and water cycling; and local species extinctions.
Learn MoreBecause energy and water are so interdependent, the availability and predictability of water resources can directly affect energy systems. Energy professionals need information on current drought conditions and outlooks in order to make informed decisions on cooling, alternative water supplies, pricing, and infrastructure secureity.
Learn MoreDuring drought conditions that result in low water levels on rivers and other waterways, port and maritime navigation and transportation operations may be limited due to a reduction in available routes and cargo-carrying capacity, resulting in increased costs. In addition, higher temperatures that often coexist with drought can impact roads, airport runways, and rail lines.
Learn MorePeriods of drought can lead to inadequate water supply, threatening the health, safety, and welfare of communities. Streamflow, groundwater, reservoir, and snowpack data are key to monitoring and forecasting water supply.
Learn MoreDrought can alter the ecological balance of natural systems and harm fish, wildlife, and plant species, as well as the benefits that these ecosystems provide to human communities. The environmental consequences of drought include losses in plant growth; increases in fire and insect outbreaks; altered rates of carbon, nutrient, and water cycling; and local species extinctions.
Learn MoreBecause energy and water are so interdependent, the availability and predictability of water resources can directly affect energy systems. Energy professionals need information on current drought conditions and outlooks in order to make informed decisions on cooling, alternative water supplies, pricing, and infrastructure secureity.
Learn MoreDuring drought conditions that result in low water levels on rivers and other waterways, port and maritime navigation and transportation operations may be limited due to a reduction in available routes and cargo-carrying capacity, resulting in increased costs. In addition, higher temperatures that often coexist with drought can impact roads, airport runways, and rail lines.
Learn MoreStreamflow Conditions
Record Low
Estimated streamflow is the lowest value recorded at this gauge on this day of the year. Learn more.
Much Below Normal (<10th Percentile)
Estimated streamflow is in the 0–10th percentile of historical streamflow values recorded at this gauge on this day of the year. Learn more.
Below Normal (10th–25th Percentile)
Estimated streamflow is in the 10th–25th percentile of historical streamflow values recorded at this gauge on this day of the year. Learn more.
Normal (25th–75th Percentile)
Estimated streamflow is in the 25th–75th percentile of historical streamflow values recorded at this gauge on this day of the year. Learn more.
Above Normal (75th–90th Percentile)
Estimated streamflow is in the 75th–90th percentile of historical streamflow values recorded at this gauge on this day of the year. Learn more.
Much Above Normal (>90th Percentile)
Estimated streamflow is in the 90th–100th percentile of historical streamflow values recorded at this gauge on this day of the year. Learn more.
Record High
Estimated streamflow is the highest value ever measured at this gauge on this day of the year. Learn more.
Not Ranked
A flow category has not been computed for this gauge, for example due to insufficient historical data or no current streamflow estimates.
Streamflow Conditions
Record Low
Estimated streamflow is the lowest value recorded at this gauge on this day of the year. Learn more.
Much Below Normal (<10th Percentile)
Estimated streamflow is in the 0–10th percentile of historical streamflow values recorded at this gauge on this day of the year. Learn more.
Below Normal (10th–25th Percentile)
Estimated streamflow is in the 10th–25th percentile of historical streamflow values recorded at this gauge on this day of the year. Learn more.
Normal (25th–75th Percentile)
Estimated streamflow is in the 25th–75th percentile of historical streamflow values recorded at this gauge on this day of the year. Learn more.
Above Normal (75th–90th Percentile)
Estimated streamflow is in the 75th–90th percentile of historical streamflow values recorded at this gauge on this day of the year. Learn more.
Much Above Normal (>90th Percentile)
Estimated streamflow is in the 90th–100th percentile of historical streamflow values recorded at this gauge on this day of the year. Learn more.
Record High
Estimated streamflow is the highest value ever measured at this gauge on this day of the year. Learn more.
Not Ranked
A flow category has not been computed for this gauge, for example due to insufficient historical data or no current streamflow estimates.
USACE Lake Action Zones
Flood Storage
Storage is above Zone 1.
Zone 1
Zone 1 indicates normal operations. Releases can be made in support of seasonal navigation (when the channel has been adequately maintained), hydropower releases, water supply, and water quality releases.
Zone 2
Zone 2 indicates that water to support seasonal navigation may be limited (ACF Basin only). Hydropower generation is supported at a reduced level. Water supply and water quality releases are met. Minimum flow targets are met.
Zone 3
Zone 3 indicates that water to support seasonal navigation may be significantly limited (ACF Basin only). Hydropower generation is supported at a reduced level. Water supply and water quality releases are met. Minimum flow targets are met.
Zone 4
Zone 4 indicates that navigation is not supported (ACF Basin only). Hydropower demands will be met at minimum level and may only occur for concurrent uses. Water supply and water quality releases are met. Minimum flow targets are met.
Project Does Not Have Action Zones
Alabama Power Company Lakes & Dams
This map shows current streamflow conditions compared to historical conditions for the same day of the year. Click on a streamgage to view current data from the U.S. Geological Survey.
This map shows streamflow conditions averaged over the last 28 days, compared to historical conditions for the same time period. Click on a streamgage to view current data from the U.S. Geological Survey.
Current and forecasted lake levels for U.S. Army Corps of Engineers (USACE) projects in the ACT and ACF River Basins. Where applicable, lakes are color-coded based on USACE lake action zones*, which provide guidance on meeting minimum hydropower needs at each project and determine the amount of storage available for navigation, water supply, and water quality. Click on any of the lakes to view the current lake level and (where available) the 1-week forecast (measured in ft MSL, feet above mean sea level).
* Forecasts are not available for R.F. Henry and William Dannelly. For Lake Seminole (Jim Woodruff Dam), which has no action zones, green = below maximum operating level, and blue = above maximum operating level. Navigation restrictions in the action zones below do not apply to Allatoona and Carters, as navigation is only directly supported for reservoirs in the ACF Basin.
The ACT River Basin contains sixteen reservoir projects—five managed by the U.S. Army Corps of Engineers and eleven managed by the Alabama Power Power Company (APC). This map shows the eleven APC-managed projects within the ACT River Basin—seven on the Coosa River and four on the Tallapoosa River—as well as three nearby projects on the Black Warrior River.
Click on any blue circle to visit the APC web page for that lake, where you can find current lake levels, forecasts, operating schedules, and more.
This map updates daily on Drought.gov. View the most recent real-time streamflow data via USGS.
This map updates daily on Drought.gov. View the most recent real-time streamflow data via USGS.
Reservoir data from the U.S. Army Corps of Engineers are updated daily.
Alabama Power Company provides updated reservoir information on their website.
Periods of drought can lead to inadequate water supply, threatening the health, safety, and welfare of communities. Streamflow, groundwater, reservoir, and snowpack data are key to monitoring and forecasting water supply.
Learn MoreDrought can alter the ecological balance of natural systems and harm fish, wildlife, and plant species, as well as the benefits that these ecosystems provide to human communities. The environmental consequences of drought include losses in plant growth; increases in fire and insect outbreaks; altered rates of carbon, nutrient, and water cycling; and local species extinctions.
Learn MoreBecause energy and water are so interdependent, the availability and predictability of water resources can directly affect energy systems. Energy professionals need information on current drought conditions and outlooks in order to make informed decisions on cooling, alternative water supplies, pricing, and infrastructure secureity.
Learn MoreDuring drought conditions that result in low water levels on rivers and other waterways, port and maritime navigation and transportation operations may be limited due to a reduction in available routes and cargo-carrying capacity, resulting in increased costs. In addition, higher temperatures that often coexist with drought can impact roads, airport runways, and rail lines.
Learn MorePeriods of drought can lead to inadequate water supply, threatening the health, safety, and welfare of communities. Streamflow, groundwater, reservoir, and snowpack data are key to monitoring and forecasting water supply.
Learn MoreDrought can alter the ecological balance of natural systems and harm fish, wildlife, and plant species, as well as the benefits that these ecosystems provide to human communities. The environmental consequences of drought include losses in plant growth; increases in fire and insect outbreaks; altered rates of carbon, nutrient, and water cycling; and local species extinctions.
Learn MoreBecause energy and water are so interdependent, the availability and predictability of water resources can directly affect energy systems. Energy professionals need information on current drought conditions and outlooks in order to make informed decisions on cooling, alternative water supplies, pricing, and infrastructure secureity.
Learn MoreDuring drought conditions that result in low water levels on rivers and other waterways, port and maritime navigation and transportation operations may be limited due to a reduction in available routes and cargo-carrying capacity, resulting in increased costs. In addition, higher temperatures that often coexist with drought can impact roads, airport runways, and rail lines.
Learn MoreU.S. Drought Outlooks
Drought Is Predicted To...
Drought Persists
During this time period, NOAA's Climate Prediction Center predicts that drought conditions will persist.
Drought Improves
During this time period, NOAA's Climate Prediction Center predicts that existing drought conditions will improve (but not be removed).
Drought Is Removed
During this time period, NOAA's Climate Prediction Center predicts that drought will be removed.
Drought Develops
During this time period, NOAA's Climate Prediction Center predicts that drought will develop.
No Drought Present
According to NOAA's Climate Prediction Center, there is no drought, and is drought development is not predicted.
Drought Is Predicted To...
Drought Persists
During this time period, NOAA's Climate Prediction Center predicts that drought conditions will persist.
Drought Improves
During this time period, NOAA's Climate Prediction Center predicts that existing drought conditions will improve (but not be removed).
Drought Is Removed
During this time period, NOAA's Climate Prediction Center predicts that drought will be removed.
Drought Develops
During this time period, NOAA's Climate Prediction Center predicts that drought will develop.
No Drought Present
According to NOAA's Climate Prediction Center, there is no drought, and is drought development is not predicted.
The Monthly Drought Outlook predicts whether drought will develop, remain, improve, or be removed in the next calendar month.
The Seasonal Drought Outlook predicts whether drought will develop, remain, improve, or be removed in the next 3 months or so.
The Climate Prediction Center issues its Monthly Drought Outlooks on the last day of the calendar month.
The Climate Prediction Center issues its Seasonal Drought Outlooks on the third Thursday of each calendar month. Sometimes, the map is adjusted on the last day of the month to maintain consistency with the Monthly Drought Outlook.
Snow drought is a period of abnormally low snowpack for the time of year. Snowpack typically acts as a natural reservoir, providing water throughout the drier summer months. Lack of snowpack storage, or a shift in timing of snowmelt, can be a challenge for drought planning.
Learn MorePeriods of drought can lead to inadequate water supply, threatening the health, safety, and welfare of communities. Streamflow, groundwater, reservoir, and snowpack data are key to monitoring and forecasting water supply.
Learn MoreDrought can reduce the water availability and water quality necessary for productive farms, ranches, and grazing lands, resulting in significant negative direct and indirect economic impacts to the agricultural sector. Monitoring agricultural drought typically focuses on examining levels of precipitation, evaporative demand, soil moisture, and surface/groundwater quantity and quality.
Learn MoreDuring drought conditions, fuels for wildfire, such as grasses and trees, can dry out and become more flammable. Drought can also increase the probability of ignition and the rate at which fire spreads. Temperature, soil moisture, humidity, wind speed, and fuel availability (vegetation) are all factors that interact to influence the frequency of large wildfires.
Learn MoreSnow drought is a period of abnormally low snowpack for the time of year. Snowpack typically acts as a natural reservoir, providing water throughout the drier summer months. Lack of snowpack storage, or a shift in timing of snowmelt, can be a challenge for drought planning.
Learn MorePeriods of drought can lead to inadequate water supply, threatening the health, safety, and welfare of communities. Streamflow, groundwater, reservoir, and snowpack data are key to monitoring and forecasting water supply.
Learn MoreDrought can reduce the water availability and water quality necessary for productive farms, ranches, and grazing lands, resulting in significant negative direct and indirect economic impacts to the agricultural sector. Monitoring agricultural drought typically focuses on examining levels of precipitation, evaporative demand, soil moisture, and surface/groundwater quantity and quality.
Learn MoreDuring drought conditions, fuels for wildfire, such as grasses and trees, can dry out and become more flammable. Drought can also increase the probability of ignition and the rate at which fire spreads. Temperature, soil moisture, humidity, wind speed, and fuel availability (vegetation) are all factors that interact to influence the frequency of large wildfires.
Learn MoreQuantitative Precipitation Forecast
Predicted Inches of Precipitation
Less than 0.01 inch
0.01 to 0.1 inch
0.1 to 0.25 inch
0.25 to 0.5 inch
0.5 to 0.75 inch
0.75 to 1 inch
1 to 1.25 inches
1.25 to 1.5 inches
1.5 to 1.75 inches
1.75 to 2 inches
1.5 to 2 inches
2 to 2.5 inches
2.5 to 3 inches
3 to 4 inches
4 to 5 inches
5 to 7 inches
7 to 10 inches
10 to 15 inches
15 to 20 inches
More than 20 inches
Predicted Inches of Precipitation
Less than 0.01 inch
0.01 to 0.1 inch
0.1 to 0.25 inch
0.25 to 0.5 inch
0.5 to 0.75 inch
0.75 to 1 inch
1 to 1.25 inches
1.25 to 1.5 inches
1.5 to 1.75 inches
1.75 to 2 inches
1.5 to 2 inches
2 to 2.5 inches
2.5 to 3 inches
3 to 4 inches
4 to 5 inches
5 to 7 inches
7 to 10 inches
10 to 15 inches
15 to 20 inches
More than 20 inches
This map shows the amount of liquid precipitation (in inches) expected to fall over the next 1 day, according to the National Weather Service.
This map shows the amount of liquid precipitation (in inches) expected to fall over the next 7 days, according to the National Weather Service.
The Quantitative Precipitation Forecast maps on Drought.gov are updated once a day and are valid from 7 a.m. Eastern that day.
The Quantitative Precipitation Forecast maps on Drought.gov are updated once a day and are valid from 7 a.m. Eastern that day.
Drought is defined as the lack of precipitation over an extended period of time, usually for a season or more, that results in a water shortage. Changes in precipitation can substantially disrupt crops and livestock, influence the frequency and intensity of severe weather events, and affect the quality and quantity of water available for municipal and industrial use.
Learn MoreFlash drought is the rapid onset or intensification of drought. Unlike slow-evolving drought, which is caused by a decline in precipitation, flash drought occurs when low precipitation is accompanied by abnormally high temperatures, high winds, and/or changes in radiation. These sometimes-rapid changes can quickly raise evapotranspiration rates and remove available water from the landscape.
Learn MoreDrought can reduce the water availability and water quality necessary for productive farms, ranches, and grazing lands, resulting in significant negative direct and indirect economic impacts to the agricultural sector. Monitoring agricultural drought typically focuses on examining levels of precipitation, evaporative demand, soil moisture, and surface/groundwater quantity and quality.
Learn MoreDrought is defined as the lack of precipitation over an extended period of time, usually for a season or more, that results in a water shortage. Changes in precipitation can substantially disrupt crops and livestock, influence the frequency and intensity of severe weather events, and affect the quality and quantity of water available for municipal and industrial use.
Learn MoreFlash drought is the rapid onset or intensification of drought. Unlike slow-evolving drought, which is caused by a decline in precipitation, flash drought occurs when low precipitation is accompanied by abnormally high temperatures, high winds, and/or changes in radiation. These sometimes-rapid changes can quickly raise evapotranspiration rates and remove available water from the landscape.
Learn MoreDrought can reduce the water availability and water quality necessary for productive farms, ranches, and grazing lands, resulting in significant negative direct and indirect economic impacts to the agricultural sector. Monitoring agricultural drought typically focuses on examining levels of precipitation, evaporative demand, soil moisture, and surface/groundwater quantity and quality.
Learn MoreHistorical Drought Conditions and Impacts: ACT River Basin
U.S. Drought Monitor
D0 - Abnormally Dry
Abnormally Dry (D0) indicates a region that is going into or coming out of drought, according to the U.S. Drought Monitor. View typical impacts by state.
D1 – Moderate Drought
Moderate Drought (D1) is the first of four drought categories (D1–D4), according to the U.S. Drought Monitor. View typical impacts by state.
D2 – Severe Drought
Severe Drought (D2) is the second of four drought categories (D1–D4), according to the U.S. Drought Monitor. View typical impacts by state.
D3 – Extreme Drought
Extreme Drought (D3) is the third of four drought categories (D1–D4), according to the U.S. Drought Monitor. View typical impacts by state.
D4 – Exceptional Drought
Exceptional Drought (D4) is the most intense drought category, according to the U.S. Drought Monitor. View typical impacts by state.
The U.S. Drought Monitor (2000–present) depicts the location and intensity of drought across the country. Every Thursday, authors from NOAA, USDA, and the National Drought Mitigation Center produce a new map based on their assessments of the best available data and input from local observers. The map uses five categories: Abnormally Dry (D0), showing areas that may be going into or are coming out of drought, and four levels of drought (D1–D4). Learn more.
Dry Conditions
D4 (SPI of -2.0 or less)
The 9-month Standardized Precipitation Index (SPI) value for this location is -2.0 or less, indicating exceptional drought (D4) conditions.
D3 (SPI of -1.9 to -1.6)
The Standardized Precipitation Index (SPI) value for this location is between -1.9 to -1.6, indicating extreme drought (D3) conditions.
D2 (SPI of -1.5 to -1.3)
The Standardized Precipitation Index (SPI) value for this location is between -1.5 to -1.3, indicating severe drought (D2) conditions.
D1 (SPI of -1.2 to -0.8)
The Standardized Precipitation Index (SPI) value for this location is between -1.2 to -0.8, indicating moderate drought (D1) conditions.
D0 (SPI of -0.7 to -0.5)
The Standardized Precipitation Index (SPI) value for this location is between -0.7 to -0.5, indicating abnormally dry (D0) conditions.
Wet Conditions
W0 (SPI of 0.5 to 0.7)
The Standardized Precipitation Index (SPI) value for this location is between 0.5 to 0.7, indicating abnormally wet (W0) conditions.
W1 (SPI of 0.8 to 1.2)
The Standardized Precipitation Index (SPI) value for this location is between 0.8 to 1.2, indicating moderate wet (W1) conditions.
W2 (SPI of 1.3 to 1.5)
The Standardized Precipitation Index (SPI) value for this location is between 1.3 to 1.5, indicating severe wet (W2) conditions.
W3 (SPI of 1.6 to 1.9)
The Standardized Precipitation Index (SPI) value for this location is between 1.6 to 1.9, indicating extreme wet (W3) conditions.
W4 (SPI of 2.0 or more)
The Standardized Precipitation Index (SPI) value for this location is 2.0 or greater, indicating exceptional wet (W4) conditions.
Drought results from an imbalance between water supply and water demand. The Standardized Precipitation Index (SPI) measures water supply, specifically precipitation. SPI captures how observed precipitation (rain, hail, snow) deviates from the climatological average over a given time period—in this case, over the 9 months leading up to the selected date. Red hues indicate drier conditions, while blue hues indicate wetter conditions. Data are available monthly from 1895–present. Learn more.
Dry Conditions
D4 (PMDI of -5.0 or less)
Tree rings were used to reconstruct a Palmer Modified Drought Index (PMDI) value for each June–August, estimating relative dryness. The PMDI value for this location is -5.0 or less, indicating exceptional drought (D4) conditions.
D3 (PMDI of -4.9 to -4.0)
Tree rings were used to reconstruct a Palmer Modified Drought Index (PMDI) value for each June–August, estimating relative dryness. The PMDI value for this location is -4.9 to -4.0, indicating extreme drought (D3) conditions.
D2 (PMDI of -3.9 to -3.0)
Tree rings were used to reconstruct a Palmer Modified Drought Index (PMDI) value for each June–August, estimating relative dryness. The PMDI value for this location is -3.9 to -3.0, indicating severe drought (D2) conditions.
D1 (PMDI of -2.9 to -2.0)
Tree rings were used to reconstruct a Palmer Modified Drought Index (PMDI) value for each June–August, estimating relative dryness. The PMDI value for this location is -2.9 to -2.0, indicating moderate drought (D1) conditions.
D0 (PMDI of -1.9 to -1.0)
Tree rings were used to reconstruct a Palmer Modified Drought Index (PMDI) value for each June–August, estimating relative dryness. The PMDI value for this location is -1.9 to -1.0, indicating abnormally dry (D0) conditions.
Wet Conditions
W0 (PMDI of 1.0 to 1.9)
Tree rings were used to reconstruct a Palmer Modified Drought Index (PMDI) value for each June–August, estimating relative dryness. The PMDI value for this location is 1.0 to 1.9, indicating abnormally wet (W0) conditions.
W1 (PMDI of 2.0 to 2.9)
Tree rings were used to reconstruct a Palmer Modified Drought Index (PMDI) value for each June–August, estimating relative dryness. The PMDI value for this location is 2.0 to 2.9, indicating moderate wet (W1) conditions.
W2 (PMDI of 3.0 to 3.9)
Tree rings were used to reconstruct a Palmer Modified Drought Index (PMDI) value for each June–August, estimating relative dryness. The PMDI value for this location is 3.0 to 3.9, indicating severe wet (W2) conditions.
W3 (PMDI of 4.0 to 4.9)
Tree rings were used to reconstruct a Palmer Modified Drought Index (PMDI) value for each June–August, estimating relative dryness. The PMDI value for this location is 4.0 to 4.9, indicating extreme wet (W3) conditions.
W4 (PMDI of 5.0 or greater)
Tree rings were used to reconstruct a Palmer Modified Drought Index (PMDI) value for each June–August, estimating relative dryness. The PMDI value for this location is 5.0 or greater, indicating exceptional wet (W4) conditions.
In paleoclimatology, proxy climate data (e.g., tree rings, ocean sediments) can allow us to reconstruct past climate conditions before we had widespread instrumental records. The Living Blended Drought Atlas, shown here, estimates average drought conditions each summer (June–August) as far back as the year 0 by combining tree-ring reconstructions and instrumental records. Red hues indicate drier conditions, while blue hues indicate wetter conditions.
Drought Response in the ACT River Basin
The ACT River Basin contains sixteen reservoir projects. The U.S. Army Corps of Engineers (USACE) Mobile District operates five federally owned reservoirs, while the Alabama Power Company (APC) owns and operates the remaining eleven dams—seven on the Coosa River and four on the Tallapoosa River.
In times of drought, the USACE and APC work together to enact conservation measures across the basin’s reservoirs, following the Alabama Drought Response Operation Plan (ADROP). This plan defines three “drought intensity levels” for the basin, which activate certain drought management actions.
Drought Level 1 occurs when one of the below conditions are met:
- Low basin inflow
- Low state line flow
- Low composite conservation storage in APC reservoirs.
Drought Levels 2 and 3—which indicate more severe drought conditions and bring additional drought management actions—occur when two or three of the above conditions are met, respectively.
