1. Drought Index For Rarotonga

2. Rarotonga Water Supply

3. Impact of drought on Rarotonga water supply

4. Temporary measures By-passes upstream of water intakes are formed to harvest available water in the streams

5. Managing Drought - Water use monitoring - Trap more water - Roof catchment - Water Restriction - Water Conservation - Restriction of non essential uses - Monitoring/Predicting Drought

6. Measuring Drought To manage drought we need to measure it Precipitation based –Standardized Precipitation Index (SPI) –Weighted Sum Precipitation Index

7. Standardised Precipitation Index

8. Weighted Sum Index Uses a time window with increasing weight given to most recent rain (a measure of catchment memory)

9. Hydrological Network – NZODA

10. Hydrological Data

11. Drought Forecast Long term rainfall forecast allows a forecast of drought persistence

12. Experimental Rainfall Prediction Rarotonga: Most recent forecast Rarotonga: September 1996

13. Useable drought forecasts: Understanding of the meaning of long-term rainfall forecasts Understanding of relationship between rainfall & catchment yield Drought response plan

14. Conclusion A drought index provides basis for management decisions A reliable drought forecast would make it possible to make an earlier decision and the response will be more effective The simple drought index “Weighted Sum” is a first step in measuring drought, this will be adapted as we gain experience and more data