current, innovative, and standardized elevation data for flood modeling in australia: the...
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Current, Innovative, and StandardizedElevation Data for Flood Modeling in Australia:The Murray-Darling Basin
Kea M. Beiningen, CFM, GISPIntermap TechnologiesMay 19, 2010
© 2009 Intermap Technologies. All rights reserved.2
Water Act 2007
The purpose of the Basin Plan is to provide for the integratedmanagement of the Basin water resources in a way that promotesthe objects of this Act, in particular by providing for:
(a) giving effect to relevant international agreements (to the extent to which those agreements are relevant to the use and management of the Basin water resources); and
(b) the establishment and enforcement of environmentally sustainable limits on the quantities of surface water and ground water that may be taken from the Basin water resources (including by interception activities); and
(c) Basin-wide environmental objectives for water-dependent ecosystems of the Murray-Darling Basin and water quality and salinity objectives; and
(d) the use and management of the Basin water resources in a way that optimizes economic, social and environmental outcomes; and
(e) water to reach its most productive use through the development of an efficient water trading regime across the Murray-Darling Basin; and
(f) requirements that a water resource plan for a water resource plan area must meet if it is to be accredited or adopted under Division 2; and
(g) improved water security for all uses of Basin water resources.
© 2009 Intermap Technologies. All rights reserved.4
Intermap’s Core Products
ORI Orthorectified Radar ImageImage pixel size of 0.62 Meters
DSM Digital Surface ModelDTM Digital Terrain Model
4 © 2010 Intermap Technologies. All rights reserved.
Pixel Size (m) RMSE (m)
1.25 2.0
© 2009 Intermap Technologies. All rights reserved.5
Travellers Lake, Australia
Google Earth, Spot Image DSM on top of image
© 2009 Intermap Technologies. All rights reserved.6
NEXTMap Specs
Measures of Accuracy (Meters)
Product Type
RMSE 95% Mean and Standard Deviation
I 0.7 1.5 0.5 0.5
II 1.0 2.0 0.7 0.7
DTM:
Measures of Accuracy
Product Type
RMSE 95% Mean Standard Deviation
I 0.5 1.0 0.3 0.3
II 1.0 2.0 0.7 0.7
III 3.0 6.0 2.0 2.0
DSM:
© 2009 Intermap Technologies. All rights reserved.7
Source Data Used
Base data provided by MDBA568 tiles of NEXTMap data from IntermapMGA Zone 54 projection (same as UTM 54
South)GDA 1994 datumEach tile
• 10 km by 10 km• Array of 2000 x 2000 5-meter cells
Vertical datum is AUSGeoid98Vertical and horizontal units are meters
Orthorectified radar images (ORI)
© 2009 Intermap Technologies. All rights reserved.8
Overview
Analyzed basin: ~46,000 sq kmHydrology: Regression equations function of drainage area in square kilometersRiverine-Like Hydraulics: 2-, 10-, 50-, 100-, and 500-year return intervals for riverine areasNon-Riverine Hydraulics: Pits and pondsFloodplain Mapping: Pits & Ponds + RiverineArcHydro data model
© 2009 Intermap Technologies. All rights reserved.9
Assumptions & Limitations
Pilot-level study, test purposes onlyHighly automated, minimal human interventionBroad assumptions in certain input valuesVery short production time frame (December 2009)Used best available input data at time of work
© 2009 Intermap Technologies. All rights reserved.10
Riverine-like Portions of Study Area
Steady flow hydraulic models and mapping developed where: Drainage areas 20 sq km or moreContributing area completely
contained by the supplied topography.
Where the reaches somewhat riverine in nature
PBS&J Rapid Floodplain Delineation (RFD) tool usedStep-backwater computationAbility to write HEC-RAS files
© 2009 Intermap Technologies. All rights reserved.11
Topography Used
Common industry standard for hydrologic analysis is 30-meter cells used to develop basins and flowpaths for hydrology. For this project, topography resampled to 25-
meters (slightly smaller than typical 30-meter cell size)
HydraulicsResampled to a 10-meter cell size for speed of
analysis reasonsFlowpaths were "splined" to smooth them out
© 2009 Intermap Technologies. All rights reserved.12
Regression Equations for Flows
Annual peak flow gage data available for portions of regionGage annual maximum peak flow series fitted to the Gumbel (Type 1) Extreme Value distribution. 2-, 10-, 50-, 100-, and 500-year
Flow equation developed where drainage area was only variable
© 2009 Intermap Technologies. All rights reserved.13
Cross Sections (XS)
Cross SectionsRFD has several parameters that
impact XS placementFor this pilot study, values set
reach-by-reach in GISVery minimal manual
manipulation of XS for this study
Standard Manning n value used
© 2009 Intermap Technologies. All rights reserved.14
Dry Lakes and Pits / Ponds
Only about 25% of the basin riverine-likeRest appears has few or no discernable channels—is not riverine flow. “Ponding" layer shows ponds & pits In excess of about 0.3 meters in depth And, approximately 1 hectare in surface area.
Over 50,000 polygons in the study areaUse pits-ponds layer from riverine models in conjunction with the ponding layer.
Greater extent of two layers is estimated floodplain
© 2009 Intermap Technologies. All rights reserved.15
Murray and Darling Rivers
Murray and Darling RiversMajority of contributing basins
outside the study area Effects of regulationModeled using historic peak
flows from early 1990sFor Murray RiverFlows roughly equal to 1956
flooding extents also used ~2,265 cms U/S of the Darling ~2,549 cms D/S of the Darling
© 2009 Intermap Technologies. All rights reserved.16
Murray and Darling Rivers
© 2009 Intermap Technologies. All rights reserved.17
Floodplain MappingFlow Contained
© 2009 Intermap Technologies. All rights reserved.18
Floodplain MappingMurray River + Pits and Ponds
© 2009 Intermap Technologies. All rights reserved.19
Floodplain MappingOverlaid With Basin Boundaries
© 2009 Intermap Technologies. All rights reserved.20
ArcHydro
Arc Hydro Tools version 1.3 used Created after H&H modeling completeArc Hydro preprocessing workflow usedIn this case, workflow begins with the flow direction grid
© 2009 Intermap Technologies. All rights reserved.21
ArcHydro
Drainage, Hydrography, and Network feature datasets
• These are standard feature datasets in the Arc Hydro schema
Drainage feature dataset • watershed, catchment, and drainage
line featuresNetwork dataset
• connectivity of the systemHydrography dataset
• Monitoring point features (gauges)Channel feature dataset
• Not included, no channel data available
© 2009 Intermap Technologies. All rights reserved.22
What’s next???
Intermap continuing to collect IfSAR for the rest of Murray Darling Basin & now for the Eastern part of New South Wales.
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