1. South Carolina Drought Forecasting Greg Carbone and Kirstin Dow Department of Geography University of South Carolina

2. Outline Community water systems managers in South Carolina Resampling methodology applied to drought forecasting Sample products

3. Investigating CWS Managers 3 Focus groups 4 meetings with key informants Survey results from 269 managers (52%)

4. 5 - Day Forecasts3-Month Forecasts Percentage Confidence in…

5. Survey Questions Included in Use of Forecasts for Planning Percentage of “Yes” responsesSCPA Plan future water storage needs for finished water?16.813.1 Plan expanded distribution capability?16.77.4 Plan when to bring new water supplies on line?15.616.3 Adjust existing reservoir levels or back-up storage?24.424.2 Anticipate inventory supply needs or guide purchasing decisions? 19.216.5 Schedule personnel, maintenance, or construction?59.052.1 Schedule additional testing for water quality?29.328.7 Help make budget projections?22.210.8 Justify increased infrastructure investments?18.911.7 Start a public information campaign to conserve water?57.565.9

6. Summary of CWS Managers Views CWS managers’ have some confidence in climate forecasts, but…… Confidence does not increase the likelihood that CWS managers will use forecasts Level of concern over risks and severity of consequences offers greater insight into uses of forecasts

7. Drought Stage (SC Drought Response Committee) Palmer Drought Severity Index (PDSI) Standardized Precipitation Index (SPI) Keetch-Byram Index 1 Incipient-0.50 to -1.490 to -0.99300 to 399 2 Moderate-1.50 to -2.99-1.00 to -1.49400-499 3 Severe-3.00 to –3.99-1.50 to -1.99500-699 4 Extreme≤ -4.00≤ -2.00≥ 700 South Carolina Drought Stages

8. Anticipating future drought indices Resample from climatology Incorporate long-lead forecasts

10. Using Climatology (“equal chances”) 1/9 AboveNormalBelow Temperature AboveAbove NormalNormal BelowBelow Precipitation

11. 1934,1943,1960, 1965,1975,1980, 1993,1998 1944,1951,1952, 1964,1979,1983, 2003 1946,1948,1963, 1973,1976,1977, 1990,1997 1940,1942,1958, 1962,1971,1984, 1996,2001 1950,1954,1959, 1970,1972,1978, 1992,1994,2002 1935,1936,1938, 1945,1953,1961, 1968,1974,1997, 2000 1931,1932,1933, 1937,1941,1947, 1969,1987,1999 1939,1949,1956, 1957,1966,1981, 1986,1988 1955,1967,1982, 1985,1989,1995 AboveNormalBelow Temperature AboveAbove NormalNormal BelowBelow Precipitation

14. 1934,1943,1960, 1965,1975,1980, 1993,1998 1944,1951,1952, 1964,1979,1983, 2003 1946,1948,1963, 1973,1976,1977, 1990,1997 1940,1942,1958, 1962,1971,1984, 1996,2001 1950,1954,1959, 1970,1972,1978, 1992,1994,2002 1935,1936,1938, 1945,1953,1961, 1968,1974,1997, 2000 1931,1932,1933, 1937,1941,1947, 1969,1987,1999 1939,1949,1956, 1957,1966,1981, 1986,1988 1955,1967,1982, 1985,1989,1995 AboveNormalBelow Temperature AboveAbove NormalNormal BelowBelow Precipitation

17. May 2002 drought prediction (made on January 1, 2002)

22. “El Nino Projections” (made 1 June 2002)

23. “El Nino Projections”

24. Final Thoughts Seasonal temperature and precipitation forecasts can be used for “secondary products” that address particular concerns and awareness –Risk aversion, past experience Since interannual variability swamps marginal probability shifts, exploit the historical climate record Purveyors need regional-scale appreciation for user knowledge base and requirements

26. Community Water Systems Provide water to at least 25 people or 15 service connections year round (EPA) Variety of water sizes, water sources Risk aversion: reliability/resilience built into management and systems Other management criteria: profitability, competitiveness, politically influenced

34. Drought Stage (SC Drought Response Committee) Palmer Drought Severity Index (PDSI) Standardized Precipitation Index (SPI) Keetch-Byram Index 1 Incipient-0.50 to -1.490 to -0.99300 to 399 2 Moderate-1.50 to -2.99-1.00 to -1.49400-499 3 Severe-3.00 to –3.99-1.50 to -1.99500-699 4 Extreme≤ -4.00≤ -2.00≥ 700