Responding to Extreme Drought in the Murray-Darling Basin, Australia. David Dreverman, Executive Director, River Murray

Transcription

1 Responding to Extreme Drought in the Murray-Darling Basin, Australia David Dreverman, Executive Director, River Murray Murray-Darling Basin Authority March 2010

2 Government Jurisdictions Australian Government Queensland South Australia New South Wales Victoria Australian Capital Territory

3 Average Rainfall Distribution

4 River Murray System Catchment affected by low inflows in 2006/07 2/3 of urban/ domestic demand is downstream of SA Border ~330 GL critical human needs (restricted) Adelaide: most downstream major supply point SA ~2 Million people urban water supply is about 10% of water used in an average year

5 Water Outlook in Spring 2006 The River Murray System was facing: lowest on record rainfall for six months Feb to Oct 2006 across most of high yielding alpine catchments; record low system inflows; less water for whole year than had been allowed for planning purposes; prospect of record low water availability in with another dry year; prospect or urban water supply difficulties if was as dry as

6 Rainfall Deciles 9 months February to October 2006

7 River Murray System Inflows (including Darling) Annual Totals Total River Murray System Inflows (including Darling River) Modelled Annual Inflows - current conditions Annual Inflow (GL) Long-term Average Inflow ( GL/yr) GL/yr GL/yr Average Inflows during Drought Periods GL/yr

8 Inflows to the River Murray Long Term Average and Selected Years 2000 Inflows to the River Murray Selected Years -v- Long Term Average Modelled Current Conditions to June 2000, Actual Data from July 2000 Total Monthly Inflow (GL) Long Term Average JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC

9 River Murray Inflows Outlook in extreme dry Long term average Min. to June Volume (GL) repeat of 2002/ / / / / / / / /08

10 River Murray Diversions Outlook in extreme dry Long Term Average Diversion Min. to June Volume (GL) repeat of 2002/ / / / / / / / /08

11 Indicative 2007/08 scenarios Murray system inflows (excluding Snowy) Historic maximum Long term average 9000 Storage levels return towards long term average / Good year for irrigators Broad order estimate only. Actual outcomes will depend on spatial distribution of runoff and management arrangements. GL 4000 No irrigation in SA and urban water supplies require careful management % water right in Vic NSW high security reasonably assured 2002/ Urban water supplies in NSW/Vic reasonably assured but restricted Min use for planning / 2007? Critical operation to meet urban supplies only Below this level, Adelaide and SA towns at significant risk 0

12 Dry Inflow Contingency Planning Senior Officials Group (SOG) established in Nov 2006 by agreement of First Ministers; SOG meets frequently (approx. every four to six weeks for the next two years; SOG replaced in Dec 2008 by Basin Officials Committee;

13 Dry Inflow Contingency Planning (cont d) SOG/BOC involve the senior water managers of states of NSW, Victoria, South Australia, Australian Government, Australian Capital Territory and MDBC/MDBA; SOG reported to First Ministers; BOC reports to Murray-Darling Basin Ministerial Council;

14 Dry Inflow Contingency Planning (cont d) Decisions mainly implemented through powers of Murray-Darling Basin Agreement.

15 Record low inflows over ten years

16 Record low inflows over ten years

17 Record low inflows over ten years

18 Record low inflows over ten years

19 Record low inflows over ten years

20 River Murray Diversions

21 Lessons Learned Sound governance is essential. When sovereign governments need to agree changes to rules there is unlikely to be an option that provides a win-win outcome. The best that we achieved in the Murray-Darling Basin was a least pain outcome.

22 Lessons Learned (cont d) So far our worst case scenario has not occurred, even though inflows tracked at or close to worst case assumptions for many months. Severe drought accelerates the need for further reform. Trade works.

23 Lessons Learned (cont d) Carryover of unused water by individual irrigators works and allows better management of risk at enterprise level.