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Project description and study area
The Department of Planning and the Department of Transport are undertaking a project to assess coastal vulnerability and prepare for possible sea level rise associated with global warming.
The project involves the collection of data over an area of coastline between Two Rocks (northern boundary of the Perth metropolitan region) and Cape Naturaliste.
The study area extends seaward from the waterline at the coast to the nominal -20 metre marine nautical navigation chart contour, and includes seven selected shoals.
The near-shore bathymetry and seabed type data collected will form the basis for 3D models of the ocean floor.
The data is being collected by performing a “LiDAR” hydrographic survey. LiDAR is the acronym for Light Detection And Ranging. This aircraft borne remote sensing technology rapidly transmits pulses of light that reflect off the underwater terrain and other marine features.
The LiDAR survey will provide detailed data that scientists and engineers will use in ongoing research.
Project aims and objectives
The objective of the project is to acquire bathymetric and seabed data using LiDAR technology and to develop a high resolution coastal 3D model.
The first stage of the project is the data collection. Data is being collected for the area seaward from the waterline at the coast to the nominal -20 metre marine nautical navigation chart contour, as well as for seven selected shoals within the study area. Data is being collected at 5 metre x 5 metre resolution.
Data is captured by an aircraft transmitting rapid pulses from two lasers and recording the return signals. The red light reflects off the sea surface and the green light travels through the water and records information about the seabed. These lasers and the global positioning system which guides the aircraft on its flight path, form the basis of the LiDAR survey technology.
The following outcomes are expected from the first stage of the project:
- Complete and seamless data files of water depths and broad seabed classification imagery from pseudo-reflectance.
- A seamless high resolution coastal 3D model of the land and seabed.
Another term used to describe a 3D model is a digital elevation model (also referred to as a DEM). In this case, the elevations are negative depths to the seabed, measured from the approximate mean sea level.
The second stage of the project is the data processing.
The third stage of the project will involve using the digital elevation model dataset as base information to model the data. This will include:
- Monitoring the possible impacts of sea level change.
- Undertaking continuous studies to assess coastal vulnerability resulting from human impacts on the Perth metropolitan and south-west coastal strip.
- Modelling the impacts of flooding.
- Modelling groundwater, surface water, tsunamis and storm events with and without sea level rise.
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Timeframe and progress
In March 2009, Tenix LADS (Laser Airborne Depth Sounding) Corporation Pty Ltd (now Fugro LADS Corporation Pty Ltd) were awarded the contract to collect the bathymetric and seabed data using LiDAR survey technology.
The flying component of the project to collect the LiDAR data was completed at the end of April 2009. Currently all the daily flight data is being compiled and reviewed to make one complete coverage. It is expected that the final dataset will be ready to be presented to the Department of Planning by December 2009.
Future uses of the data and model
Undertaking this project is a positive step in helping planners and managers of the WA coast to understand the issues and risks from climate change impacts.
The data collected will be used as input for several purposes, such as:
- inform the development of regional and local coastal plans;
- inform the revision of the current coastal policy, State Planning Policy 2.6 State Coastal Planning Policy;
- assessment of the impacts of climate change induced rise in sea level on the coast;
- identification of areas potentially at risk from storm surge, inundation, erosion and high winds;
- support decision-making and planning of the coast;
- identifying areas where physical protection measures are required to protect assets and people;
- identify areas yet to be developed where land use planning changes will be required;
- building and testing mathematical procedures that use 3D models to imitate the impacts of environmental change;
- planning and managing natural disasters;
- planning and managing urban development along the coastal plain - used by developers, consultants, local governments and state government agencies;
- environmental modelling, such as flood, groundwater, and ecological modelling;
- preparing marine plans.
Links to other projects
Federal government
The Federal Government is coordinating a national coastal vulnerability assessment, with the aim of identifying coastal environments, communities and infrastructure at risk from the impact of climate change. The LiDAR survey data will support these aims.
To ensure WA is adequately prepared and able to manage the impact of climate change, the LiDAR will enable a coastal digital elevation model to be developed for part of WA’s coastline.
The digital elevation model will be the primary data set used to analyse the impacts of climate change on humans and the environment. The model will be an important tool used for planning and managing WA’s coastline.
Geoscience Australia and WA’s Fire and Emergency Services Authority (FESA) will be able to use the information to conduct tsunami impact studies and to improve response planning.
Department of Water
The bathymetric project will complement a recent terrestrial project undertaken by the WA Department of Water.
The Department of Water has developed a digital terrain model of the Swan Coastal Plain. The contract to undertake the land-based LiDAR survey was awarded to Fugro Spatial Solutions in January 2008. The contract to collect the land based LiDAR over 7000 km² accurate to 0.15m and at 1m x 1m resolution was conducted in February 2008. The data collected by the LiDAR survey is being processed and expected to be completed by September 2009.
The digital terrain model will be used to undertake studies to determine the behaviour of flooding, groundwater/surface water interaction and ecological systems in the Murray area. The model will also be used for other geographic areas as required.
Data from the Department of Planning and Department of Water will be available as a resource to be used by other government agencies.
For further information on the bathymetric project, please contact the Climate Change and Coastal Planning team at the Department of Planning on (08) 9264 7777.
For further information on the Department of Water’s project, please contact Peter Muirden at the Department of Water on telephone (08) 6364 6925 or email peter.muirden@water.wa.gov.au.