Floodplain inundation mapping and modelling in the northern regions, the Murray Darling Basin

[摘要] The Murray Darling Basin Authority (MDBA) have identified a need for floodplain inundation modelling/mapping to link hydrological models to ecosystem response. At the heart of the Basin Plan is the establishment of Environmentally Sustainable Levels of Take (ESLT). The ESLT was determined using flow targets as indicators of ecosystem response. It was assumed when a flow target was reached then a number of environmental objectives would also be achieved. The ability to make a direct link to discrete environmental responses was limited due to hydrological models contained insufficient information about these responses, including the location and extent of vegetation species in the Basin.Future business requirements under various MDBA business functions (a few listed below) require more direct links between managed flow events and ecosystem responses.- the Sustainable Diversion Limit (SDL) adjustment mechanism,- Constraints Management Strategy,- Environmental Watering Plans,- The Northern Basin Review/Implementation, and- Monitoring and EvaluationInforming the above business functions means further investments are needed to strengthen the hydrological models with additional information such as floodplain inundated area extents associated with increasing flows. The MDBA has engaged CSIRO for this type of modelling for most of the Southern Basin regions including, the Murray River, The Edward-Wakool System, the Lower Murrumbidgee and the Lower-Darling and Great Anabranch systems (Sims et al., 2014). The River Murray Floodplain Inundation Model (RiM-FIM) (Overton et al., 2006), which was created as a research and decision-support tool for environmental flow management in the River Murray, was used for the modelling covering the above areas.Flood inundation modelling is an evolving science. In the recent years, the Land and Water Business Unit of CSIRO has been developing a more advanced methodology for large-scale flood inundation modelling by taking into consideration floodplain hydraulics and water balance. The initial version of the modelling methodology was implemented to develop a tool called TVD model using a simplified storage-based hydraulic concept for large-floodplain inundation simulation at a very high spatial resolution (Dutta et al., 2013; Teng et al., 2015). The TVD model can simulate floods under various antecedent soil moisture conditions and produce spatio-temporal details of floodplain water balance. The model is able to provide all the outputs that RiM-FIM is able to produce, plus it provides floodplain water balance and effects of antecedent conditions on flood inundation extents. The model can also be used for scenario modelling under future predictions as it is not dependent on satellite imagery.The Hydrology and Modelling Coordination section of the MDBA saw potential in using CSIRO’s new flood inundation modelling methodology, in particular with regards to the effects of antecedent condition, flood plain storage changes and connectivity with wetlands. The MDBA commissioned CSIRO to undertake this project for inundation mapping using Landsat imagery and modelling using this new methodology in a number of key floodplains within the MDB to support decision making process. The study areas included following eight different floodplains within the northern region of the MDB. The extents for flood mapping using Landsat imagery for the selected regions were identified based on the 1:100-yr return period flood inundation map for the MDB as shown in Figure 1.1.1) Lower Balonne System (LBS)2) Middle Darling System (MDS)3) Border4) Gwydir5) Macquarie6) Namoi7) Paroo8) WarregoThe main requirement of the project was to produce flood inundation mapping for:- the Lower Balonne area using the new methodology and Landsat imagery,- the Middle Darling area using the new methodology and Landsat imagery, and- six other floodplains in northern basins using Landsat imagery....

[发布机构] CSIRO

[学科分类] 地球科学(综合)