(1) This rule sets forth the manner in which the District will periodically evaluate water conditions within the District. Data thereby generated assists the District in determining whether and to what extent a water shortage should be declared.
    (2) Monitoring data – Water data and water demand data will be obtained from any source of information needed to evaluate the following:
    (a) Drought Indicators shown in Table 21-1.
    (b) Current regional surface water flows and lake levels and their relationship to low normal values.
    (c) Current and recent values of the U.S. Drought Monitor for the National Drought Mitigation Center.
    (d) Current precipitation outlooks from the Climate Prediction Center of the National Oceanic and Atmospheric Administration’s National Weather Service.
    (e) Public supply storage status.
    (3) In evaluating whether or not a Water Shortage or Water Shortage Emergency should be declared, the following evaluation process is followed:
    (a) The District will compare current data to values for specific Drought Indicators as shown in Table 21-1.
    (b) The District will compile these comparisons and consider Drought Condition Levels as shown in Table 21-2 and the factors identified in paragraphs 40C-21.251(4)(a)-(i), F.A.C., to determine the appropriate Drought Condition Level.
    (c) This evaluation will occur on at least a monthly basis.
    TABLE 21-1: Drought Indicators
DROUGHT INDICATOR VALUE
REGIONAL RAINFALL
(12-Month Moving Sum)
REGIONAL RAINFALL
(24-Month Moving Sum)
GROUND WATER LEVELS*
Moderate
12-month rainfall at or below: 40 inches
24-month rainfall at or below: 84 inches
At or below 15th percentile
Severe
12-month rainfall
at or below: 35 inches
24-month rainfall
at or below: 79 inches
At or below 10th percentile
Extreme
12-month rainfall
at or below: 30 inches or 4-week duration of rainfall at or below the severe indicator
24-month rainfall
at or below: 74 inches or 4-week duration of rainfall at or below the severe indicator
At or below 10th percentile for greater than 4 weeks
Critical
12-month rainfall
at or below: 25 inches or 8-week duration of rainfall at or below severe indicator
24-month rainfall
at or below: 69 inches or 8-week duration at or below severe indicator
At or below 10th percentile for greater than 8 weeks
* Calculated based on at least 30 years of historical data
    TABLE 21-2: Drought Condition Levels
Drought Condition Level
Drought Indicator Values
Moderate
At least two Drought Indicator Values are Moderate
Severe
All Drought Indicator Values are Moderate or at least one is Severe
Extreme
Two or more Drought Indicator Values are Severe or at least one is Extreme
Critical
Two or more Drought Indicator Values are Extreme or at least one is Critical
Rulemaking Authority 373.044, 373.113 FS. Law Implemented 373.175, 373.246 FS. History-New 1-1-84, Amended 9-16-92, 6-7-93, 8-23-18.