Historical Flood Mapping from Satellite
Imagery
Norman Mueller
National Earth Observation Group
National Flood Risk Information Project
• Following the Natural Disaster Insurance Review 2011:
• Geoscience Australia to develop a portal for flood studies and
water observations from satellite imagery.
• Engineers Australia to revise national guidelines for flood
modelling and collection, comparability and reporting of flood
risk information.
• The purpose is to provide a single authoritative source of
flood related information for use by all or any sector, including
local governments, industry and the public.
National Flood Risk Information Portal
Earth Observation Component of NFRIP
• Analyse satellite imagery to find surface water.
• Derived from the historical satellite imagery available to
Geoscience Australia, in particular the archive of Landsat-5
and Landsat-7 imagery for the period of 1987 to 2012.
• A “time series” of water observations for all of Australia.
• The time-series of observed water to be queried or combined
with other data to generate map products and web feature
services.
• Provides information on where water has been seen in the
past and helps to inform where flooding may have occurred.
National Flood Risk Information Portal
Landsat
Landsat-5, -7 and -8
• Medium spatial resolution (25m
x 25m pixel)
• Views the same area every 16
days
• Regional coverage 185km wide
path
How to show flood information?
Medium resolution (Landsat) – 185km wide strips across
Australia repeated every 16 days
Single flood extents
• gives a single snapshot of one flood only, often only partial
• loses continuity across swath edges
Summary flood products
• shows the behaviour of water in an area for all images over all
available snapshots through time
• displaying ratio of detected water to number of good
observations provides continuity across swath boundaries
National Flood Risk Information Portal
What does this sort of information help to inform?
• Knowing where water has been before can help with flood planning
and mitigation
• Understanding how often water exists in a given location is
important in managing water resources (eg Broken Hill Managed
Aquifer Recharge)
• Comparing water resources with the surrounding area helps inform
environmental management and planning
• A driver for scientific infrastructure policy: The ability to provide
these information products relies on the underlying infrastructure:
• Access to satellite services / capabilities (satellite utilisation
policy)
• High performance computing to extract information (national
computational infrastructure)
• Information delivery mechanisms (open data policy)
National Flood Risk Information Portal
Water Observations from Space
• The summary product will be made available as a web service
for use in analysis packages:
• ArcGIS and similar
• Google Earth
National Flood Risk Information Portal
•
Examples of WOfS
•
Current progress has all
of Australia analysed for
the 1998 to 2012 period
National Flood Risk Information Portal
•
Chinchilla zoom-in
National Flood Risk Information Portal
•
Lake Eyre zoom-in
National Flood Risk Information Portal
Questions
National Flood Risk Information Portal