Water Journal : Water Journal June 2014
JUNE 2014 WATER 37 Ozwater Report The work of the Bureau of Meteorology consists of forecasting, information provision, assessing water resources, modernising and upgrading weather observation locations, and standardising the data consistent with information and forecasts adding value to decision making for irrigation, operations, policy, environmental ows and emergency response (Figure 5). The Bureau integrates observations and outputs from numerical weather prediction into rainfall-runoff models to produce stream ow forecasts. This is planned to be expanded to all jurisdictions in 2014 and 2015. The Australian Hydrogeological Geospatial Fabric (aka 'Geofabric') is a spatial representation of most of Australia's hydro-features and their connectivity: rivers, lakes, wetlands, reservoirs; catchment, aquifer and management area boundaries; water monitoring points, diversions; off-takes, and return points. Figure 4. The four climate drivers that in uence Australia's climate. FLOOD INUNDATION MAPPING Flood inundation maps are a useful tool for water managers and the community. They can be used to predict which land and man-made structures will be ooded for particular ow scenarios, allowing people and their possessions, stock and equipment to be relocated safely when oods do occur. MDBA uses ood inundation mapping for these reasons, and also to help us to assess how water will ow through physical constraints as part of our Constraints Management Strategy. The River Murray Floodplain Inundation Model (RiM-FIM) links daily river ow measurements to Landsat satellite observations of ooding, then predicts from the water surface height at the relevant ow gauges the distribution of water across the landscape using a Digital Elevation Model (DEM). The RiM-FIM method enables the distribution of water to be predicted at ood heights for which there are no satellite observations. Using these models it is possible to predict the distribution of inundation at 5m spatial resolution, for each 1GL increment in average daily ow at the river gauge. WATERBIRDS -- INDICATORS OF RIVER AND WETLAND HEALTH One of the more fascinating ways of assessing the environmental health of wetlands is through the insights provided by 30 years of water bird movement observations in the eastern part of Australia (Figure 7). Every year for the last 30 years, aerial y-overs of wetlands took place, observing the abundance, distribution and breeding of waterbirds over a swathe 30 kilometres wide. The water birds were arranged in functional response groups: small wading birds; piscivores ( sh-eating birds); herbivores (predominantly vegetarian); large wading birds and ducks. The numbers of waterbirds varied from 1.8 million in wet periods to as little as 100,000 during the worst drought periods of 2002--2009. Changes in water bird numbers over time is a good indicator of what is happening in the Basin. Long-term collection of waterbird data is critical across wetlands in eastern Australia and provides useful indicators at different spatial scales from the wetland to the basin. Collected data also re ects state, national and international commitments to conservation. RESTORING THE BALANCE: THE HATTAH LAKES ENVIRONMENTAL WATERING PROGRAM The Hattah Lakes system is part of the 48,000-hectare Hattah-Kulkyne National Park in northwest Victoria (Figure 8). The system relies on wet and dry periods to be healthy. River regulation and a changing climate have reduced the frequency, duration and extent of watering events and altered the seasonality; i.e. high ows in summer when they should be low, and vice versa. This resulted in serious degradation of River Red Gums and Black Box trees, native sh populations and rare and threatened species. Emergency action was taken: temporary infrastructure was used for the delivery of water (i.e. moveable pumps). In 2004, the rst aqua dam in Australia was imported to control ows in the landscape and pumping rates from the Murray into Hattah Lakes increased from 20 ML/day to 150 ML/day (Figure 8). Watering events will be informed by environmental conditions and be subject to water availability. These events will restore the role of the lakes as a drought refuge for waterbirds and other wetland-dependant species, provide important breeding habitat for waterbirds and support threatened ora and fauna species. Key Figure 3. Locations of Victorian Regional Information Sessions to inform the draft Victorian Waterway Management Strategy. Forecasts: stream ow forecasts, climate outlooks and projections Information: storages, ows, oods, entitlements, allocations, trades, restrictions, groundwater dependent ecosystems Assessments: National Water Accounts, Aust. Water Resources Assessment Modernise • Upgrade • Automate • Standardise • 463 projects Standards • Measurement • Data exchange • Open licensing • Accounting • Assurance Enabling • Archiving • Geofabric • Aquifer framework • Water balance Integration • Observations • Weather • Rainfall-runoff • Climate Figure 5. Bringing it all together. Elements of the Bureau's Improving Water Information Programme. Figure 6. An example of a ow gauging station (NSW 2014).
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