Water Forecasting Services to Manage Water Scarcity and Variability - PowerPoint PPT Presentation

Water Forecasting Services to Manage Water Scarcity and Variability Dr Dasarath (Jaya) Jayasuriya Bureau of Meteorology Assistant Director Water Forecasting Services Hydropredict 2010 21 September 2010

Australian Temperatures • All of Australia has experienced warming over the past 50 years • Some areas, have experienced a warming of 1.5 to 2  C

Australian Rainfall • Substantial increases in many parts of northern and central Australia • Substantial decreases across much of southern and eastern Australia

Water Forecasts from BOM

Water forecasting services 1-72 hours Flood Forecasts Emergency Response River Operations 7-10 days Flow Forecasts Water Allocations and 3-12 months Seasonal Predictions Supply Operations Multi years Scenario Projections Water Supply Planning

Flash flooding in Brisbane, February 2010

Normanton to Karumba Road cut, February 2010

Number Issued 100 150 200 250 300 350 400 450 500 550 600 50 0 Jul-04 Oct-04 Jan-05 Apr-05 Jul-05 Oct-05 Jan-06 Apr-06 Jul-06 Oct-06 Warnings Watches Jan-07 Apr-07 Flood warnings issued Month Jul-07 Oct-07 Jan-08 Apr-08 Jul-08 Oct-08 Jan-09 Apr-09 Jul-09 Oct-09 Jan-10 Apr-10 Jul-10

Rainfall forecast from NWP guidance

Flood forecast for Charleville, QLD

Water forecasting services 1-72 hours Flood Forecasts Emergency Response 7-10 days Flow Forecasts River Operations Water Allocations and 3-12 months Seasonal Predictions Supply Operations Multi years Scenario Projections Water Supply Planning

Short-term flow forecasting services • Forecast flows out to 7-10 days • Hydrographs or flow volumes • Probabilistic forecasts • Will be used for storage operation, environmental flow releases, scheduling river diversions and assist water markets etc. • Experimental pilot study on Ovens River in Vic.

WIRADA Water Information Research & Development Alliance

Short-term streamflow forecast product

SWIFT – Short-term Water Information Forecasting Tools

Short Term Flow Forecasting Observed since 1 Jan 2010 Forecasts SWIFT with FEWS Rain forecasts: Meso-Laps, Access-R and Access-G Rainfall-runoff: GR4J model

Sample of Outputs from Ovens Pilot Series of Forecast Hydrographs with Different Probabilities of Exceedance 1% 10% 25% 50% 75% 90% 99% Likelihood of Exceeding Specific Flood Levels Minor Flood Moderate Flood Major Flood Forecast Time

Water forecasting services 1-72 hours Flood Forecasts Emergency Response River Operations 7-10 days Flow Forecasts Water Allocations 3-12 months Seasonal Predictions and Supply Operations Multi years Scenario Projections Water Supply Planning

Seasonal prediction services • Focus on 3 months cumulative stream flow (upstream of storages, non regulated systems) • Research and development through Water Information Research and Development Alliance activities: – CSIRO’s Statistical Bayesian Joint Probability (BJP) approach – Downscaling climate inputs from global climate model to hydrological model – Dynamic Hydrological Modelling approach – Combining statistical and dynamic approaches • Early focus on user needs and engagement

Bayesian Joint Probability (BJP) Overview (Wang et al., CSIRO) The BJP modelling approach produces simultaneous predictions for multiple sites within a catchment Bayesian statistical Model predictions are parameter inference is Antecedent streamflow, probabilistic, providing a performed using Markov rainfall, climate indicators measure of uncertainty Chain Monte Carlo and (subjective) prior sampling knowledge are model inputs

Predicting seasonal streamflows.

Experimental forecast - Skills

Experimental forecast service Sep to Nov 2010 tercile summary

Experimental forecast Goulburn, Sep-Nov 2010 (3)

Experimental forecast Goulburn, Sep-Nov 2010 (1)

Experimental forecast Goulburn, Sep-Nov 2010 (2)

Experimental forecast Goulburn, Apr-Jun 2010 (1)

Experimental forecast Goulburn, Apr-Jun 2010 (2)

Experimental forecast Goulburn, Apr-Jun 2010 (4) • 7 tercile hits and  6 tercile misses  • Low skill in   Autumn         

Experimental forecast - Skills

Summary • Short-term 7 ~ 10 day river forecast pilot showing a lot of potential • Challenge is to convert the pilot to a full blown service • Seasonal (3 month forecast) going operational in December 2010 • Highly applicable to areas that relate climate indicators (Soi type) with streamflow • Dynamic modelling with downscaling work will further strengthen predictions

Thanks for listening Visit www.bom.gov.au/water Dr Dasarath Jayasuriya d.jayasuriya@bom.gov.au +61 3 86388251 or +61 419893706