The Quantification of Drought: The Quantification of Drought:

An Evaluation of State and Local Drought TriggersAn Evaluation of State and Local Drought Triggers

Hope Mizzell, Greg Carbone, Jason Caldwell

South Carolina Department of Natural Resources

WHY PLAN?

Recontructed Palmer Drought Severity Index Based on Tree-Rings

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NOAA Paleoclimatology ProgramDr. Edward Cook, Dr. David Meko, Dr. David Stahle Dr. Malcolm Cleaveland

Hydro-Illogical CycleHydro-Illogical Cycle

PopulationPopulation

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Georgia North Carolina South Carolina

1 Dot = 10,000 People

South Carolina Drought Response ActSouth Carolina Drought Response Act

1985- Established procedures for monitoring, managing, and conserving water resources during periods of drought

SC Department of Natural Resources –Land,Water & Conservation Division serves as primary agency Monitor drought conditions Coordinate State’s response

Local Drought Committee

Local Drought Plans and Ordinances

State Drought Program

State Agency Drought Committee

Drought Act and Regulations

Chairs D.R.C. & provides support

SC State & Local Drought CommitteeSCDNR

Coordinate response

Issue Drought Declarations

Consult with stakeholders

Issue nonessential water curtailment declaration

Review request for variance

Curtail nonessential water use during severe and extreme droughts

Health & safety threatened - Report conditions & recommend actions to Governor

Mediate disputes

Governor may declare drought emergency and issue emergency water curtailment regulations

Water Systems implement drought response ordinances or plans

South Carolina Model Drought Mitigation Ordinance/Plan

•SCDNR, in cooperation with SC Water Utility Council and SCDHEC developed a model drought response ordinance/plan for water systems

Reviewed by Municipal Association and SC Drought Response Committee

•SC Drought Response Act of 2000 requires that all municipalities, counties, public service districts, special purpose districts, and commissions of public works engaged in business or activity of supplying water for any purpose develop and implement drought response ordinances or plans.

Model Drought Management Plan Model Drought Management Plan and Response Ordinanceand Response Ordinance

  

Section I: Declaration of Purpose and IntentSection I: Declaration of Purpose and Intent

Section II: Definition of TermsSection II: Definition of Terms

Section III: Drought Management Plan A. IntroductionB. Designation of Water System Drought Response RepresentativeC. Description of Water System Layout, Water Sources, Capacities and YieldsD. Identification of Water System Specific Drought or Water Shortage IndicatorsE. Cooperative Agreements and Alternative Water Supply SourcesF. Description of Pre-Drought Planning EffortsG. Description of Capital Planning and Investment for System Reliability and Demand Forecasting

Drought Response Ordinance (or Resolution)Drought Response Ordinance (or Resolution)

A.    Declaration of Policy and AuthorityA.    Declaration of Policy and Authority

B.    Moderate Drought PhaseB.    Moderate Drought Phase

C.    Severe Drought PhaseC.    Severe Drought Phase

D.    Extreme Drought PhaseD.    Extreme Drought Phase

E.    RationingE.    Rationing

F.     Enforcement of RestrictionsF.     Enforcement of Restrictions

G.   VariancesG.   Variances

H.    Status of the OrdinanceH.    Status of the Ordinance

Resolution of AdoptionResolution of Adoption

Importance of State and Local Drought Triggers

4 phases of drought established by regulation

 Incipient PDSI -0.50 to -1.49 CMI 0.00 to -1.49 SPI 0.00 to -0.99KBDI 300 to 399 DM D0Avg daily streamflow 111%-120% of minimum flow for 2 consecutive weeksStatic water level in aquifer is 11-20 feet above trigger level for 2 cons. months Moderate PDSI -1.50 to -2.99 CMI -1.50 to -2.99 SPI -1.00 to -1.49KBDI 400 to 499 DM D1Avg daily streamflow 101%-110% of minimum flow for 2 consecutive weeksStatic water level in aquifer is 1-10 feet above trigger level for 2 cons. months Severe PDSI -3.00 to -3.99 CMI -3.00 to -3.99 SPI -1.50 to -1.99KDBI 500 to 699 DM D2Avg daily streamflow is between minimum flow and 90% of minimum for 2 cons. weeksStatic water level in aquifer is between trigger level and 10 feet below for 2 cons. months Extreme PDSI -4.00 and below CMI -4.00 and below SPI -2.00 and belowKBDI exceeds 700 DM D3 or higherAvg daily streamflow less than 90% of minimum for 2 consecutive weeksStatic water level in aquifer is more than 10 feet below trigger level for 2 consecutive months

Importance of State and Local Drought Triggers

Water System Specific Triggers

Moderate/Severe/Extreme Drought Phases1.     Reservoirs ________ full2.     Storage falls below ____ percentage of capacity3.     Stream-flow less than ______ cubic feet per second 4.     Aquifer levels less than ______________5.        ____________number of days of supply remaining6.     Average daily use greater than _____mgd for _____ consecutive days 7.     Others: ______________________________________________

SJWD Water System

Percentage of Storage VolumePercentage of Storage Volume

30%

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arApr

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Per

cent

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of S

tora

ge V

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Normal

Phase 1: Incipient Drought

Phase 2: Moderate Drought

Phase 3: Severe Drought

Phase 4: Extreme Drought

Lyman Lake Drought Operating Curves

Drought Stage ThresholdsDrought Stage Thresholds

Lyman Lake Drought Operating Curves

833.0

834.0

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Normal

Phase 1: Incipient Drought

Phase 2: Moderate Drought

Phase 3: Severe Drought

Phase 4: Extreme Drought

Operating Curve PerformanceOperating Curve Performance(50-year Simulated Record)(50-year Simulated Record)

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1947 1950 1953 1956 1959 1962 1965 1968 1971 1974 1977 1980 1983 1986 1989 1992 1995 1998 2001

Sto

rage [

mgal]

Simulated Volume (15.52 mgd) Phase 1 Phase 2 Phase 3 Phase 4

Frequency of Drought Phase Indication (14.1 mgd Withdrawal)

Drought Phase

Percent of 54-year Historical

Record for Lake Lyman

Number of Weeks During 54-year Record

Public Notices During 54-year

Record

Normal 90.1% 2544 N/A

Incipient Drought (Phase 1) 1.1% 32 15

Moderate Drought (Phase 2) 2.1% 59 15

Severe Drought (Phase 3) 3.4% 97 14

Extreme Drought (Phase4) 3.3% 92 5

Frequency of Drought Phase IndicationFrequency of Drought Phase Indication

Comparison of Lake Lyman Elevation, Comparison of Lake Lyman Elevation, PDSI and 3 month SPIPDSI and 3 month SPI

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SPI 3 Month

PDSI

Elevation ft

Comparison of Lake Lyman Elevation, Comparison of Lake Lyman Elevation, PDSI and 3 month SPI:PDSI and 3 month SPI:

1998-20031998-2003

Frequency of Drought Phase Indication

Drought Phase

Percent of 54-year Historical

Record for Lake Lyman

Percent of 54-year Historical Record for SPI

Percent of 54-year Historical Record for PDSI

Normal90.1% 53.5% 56%

Incipient Drought (Phase 1)1.1% 31.5% 13.2%

Moderate Drought (Phase 2)2.1% 9.2% 24.1%

Severe Drought (Phase 3)3.4% 2.9% 5.3%

Extreme Drought (Phase4)3.3% 2.9% 1.2%

Frequency of Drought Phase IndicationFrequency of Drought Phase Indication

National Drought Preparedness National Drought Preparedness Act of 2003Act of 2003

June 21, 2004, Western Governors, Creating a Drought Early Warning System for the 21st Century: The National Integrated Drought Information System (NIDIS)

One Goal of NIDIS

Create a drought “early warning system” capable of providing accurate, timely and integrated information on drought conditions at the relevant spatial scale to facilitate proactive decisions aimed at minimizing the economic, social and ecosystem losses associated with drought;

Future WorkFuture Work

Compare additional state drought indices such as KBDI, Streamflow, Groundwater with several Local Water System Triggers such as those using wells

Evaluate drought strength, frequency, mean and maximum duration of droughts of a given intensity, and trend in drought incidence as indicated by the local and State triggers