The Quantification of Drought: An Evaluation of State and Local Drought Triggers

1. The Quantification of Drought: An Evaluation of State and Local Drought Triggers Hope Mizzell, Greg Carbone, Jason Caldwell South Carolina Department of Natural Resources

2. WHY PLAN?

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

4. Hydro-Illogical Cycle

5. Population 1 Dot = 10,000 People

6. South 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

7. South Carolina's Hydro-Logical Cycle Local Drought Plans and Ordinances State Drought Program State Agency Drought Committee Local Drought Committee Drought Act and Regulations

8. SCDNR SC State & Local Drought Committee Consult with stakeholders Chairs D.R.C. & provides support Coordinate response Issue Drought Declarations Issue nonessential water curtailment declaration Mediate disputes Curtail nonessential water use during severe and extreme droughts Review request for variance Water Systems implement drought response ordinances or plans Health & safety threatened - Report conditions & recommend actions to Governor Governor may declare drought emergency and issue emergency water curtailment regulations

9. South Carolina Model Drought Mitigation Ordinance/Plan • 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. • 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

10. Model Drought Management Plan and Response Ordinance Section I: Declaration of Purpose and Intent Section II: Definition of Terms Section III: Drought Management Plan A. Introduction B. Designation of Water System Drought Response Representative C. Description of Water System Layout, Water Sources, Capacities and Yields D. Identification of Water System Specific Drought or Water Shortage Indicators E. Cooperative Agreements and Alternative Water Supply Sources F. Description of Pre-Drought Planning Efforts G. Description of Capital Planning and Investment for System Reliability and Demand Forecasting

11. Drought Response Ordinance (or Resolution) A.    Declaration of Policy and Authority B.    Moderate Drought Phase C.    Severe Drought Phase D.    Extreme Drought Phase E.    Rationing F.     Enforcement of Restrictions G.   Variances H.    Status of the Ordinance Resolution of Adoption

12. 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 -0.99 KBDI 300 to 399 DM D0 Avg daily streamflow 111%-120% of minimum flow for 2 consecutive weeks Static 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 -1.49 KBDI 400 to 499 DM D1 Avg daily streamflow 101%-110% of minimum flow for 2 consecutive weeks Static 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 -1.99 KDBI 500 to 699 DM D2 Avg daily streamflow is between minimum flow and 90% of minimum for 2 cons. weeks Static 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 below KBDI exceeds 700 DM D3 or higher Avg daily streamflow less than 90% of minimum for 2 consecutive weeks Static water level in aquifer is more than 10 feet below trigger level for 2 consecutive months

13. Importance of State and Local Drought Triggers Water System Specific Triggers Moderate/Severe/Extreme Drought Phases 1.Reservoirs ________ full 2.Storage falls below ____ percentage of capacity 3.Stream-flow less than ______ cubic feet per second 4.Aquifer levels less than ______________ 5.____________number of days of supply remaining 6.Average daily use greater than _____mgd for _____ consecutive days 7.Others: ______________________________________________

14. SJWD Water System

15. Lyman Lake Drought Operating Curves Percentage of Storage Volume

16. Lyman Lake Drought Operating Curves Drought Stage Thresholds

17. Operating Curve Performance(50-year Simulated Record)

18. 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 Indication

19. Comparison of Lake Lyman Elevation, PDSI and 3 month SPI

20. Comparison of Lake Lyman Elevation, PDSI and 3 month SPI:1998-2003

21. 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 Normal 90.1% 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 Indication

22. National Drought Preparedness Act 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;

23. Future 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