" The Australian Oil Spill Response Atlas and Introduction

of a New Oil Spill Trajectory Model"

Trevor Gilbert

Principal Adviser, Scientific & Environmental

Maritime Safety & Environmental Strategy

Australian Maritime Safety Authority.

Email Trevor.Gilbert@amsa.gov.au

Abstract

Australia’s marine and coastal environments are not only important natural resources but important for the economic future of the nation. Oil spills in the Australian marine environment can have wide spread impact and long-term consequences on wildlife, fisheries, coastal and marine habitats, human health and livelihood, as well as recreational resources of coastal communities.

The Australian Maritime Safety Authority has recently completed a series of new initiatives involving new technological developments to assist in oil and chemical pollution response in the marine environment. This paper will discuss the technologies now being employed for improving the modelling of oil slick trajectories and the development of an environmental geographic information system to support spill response decision making.

Introduction

Since October 1973 Australia has had in place a pre-planned national strategy to respond to marine spills. The original strategy dealt only with oil spills but in April 1998 the strategy was extended to deal with the response to maritime chemical spills in Australian waters. The national contingency plan is now known as the National Plan to Combat Pollution of the Sea by Oil and other Noxious and Hazardous Substances (National Plan).

The National Plan is an integrated Commonwealth Government, State, Territory and industry organisational framework enabling the effective response to marine pollution incidents anywhere in Australian waters. The Australian Maritime Safety Authority (AMSA) manages the National Plan on behalf of the Federal Government, working with State/Northern Territory (NT) governments, the shipping, oil, exploration and chemical industries, emergency services and fire brigades to maximise Australia's marine pollution response capability. Funding, equipment and training programs to support National Plan activities are coordinated by AMSA on advice from the National Plan Advisory Committee (NPAC).

In emergency response the old adage stands true ‘Poor information makes bad decisions and good information makes better decisions.” It is vital that oil spill response organisations have access to good information and well organised decision support systems. On behalf of the National Plan AMSA has been undertaking a number of major projects to improve the provision of environmental, scientific and technical decision support to the National Plan. These projects include;

- an improved Australia wide computer based Oil Spill Trajectory Model

- a Geographic Information System based Oil Spill Response Atlas

These decision support systems are now in operation for the National Plan to support State/NT and industry spill responders. This paper highlights some of the system details, features and potential uses in supporting marine pollution incidents and maritime search and rescue planning.

National Plan Oil Spill Trajectory Modelling

When an oil spill occurs at sea the first and primary concern of response planners is; where will the oil go? That is, what is the slick direction, it’s speed of movement, weathering and spreading characteristics of the oil under the influence of prevailing currents and weather conditions?

In near-shore marine environments the tracking of oil spills, which are likely to impact the shoreline, is of prime importance in the effective deployment of oil spill response personnel and equipment to protect environmentally sensitive areas and in clean-up planning.

Oil spill trajectory models (OSTMs) provide this essential decision support but must meet a number of requirements to be of use to emergency responders and incident planners^.(1) They must provide;

· accurate spill prediction for both forecasting and hindcasting,

· rapid output of results regardless of spill geographic location,

· ability to adjust inputs considering changing conditions and field observations,

· use in remote field locations or effective transmission of model outputs to field operators,

· user friendly operation of the software and its ease of generating model outputs^{. (1)}

Over past few years, and in conjunction with AMSA’s Australian Search & Rescue unit (AusSAR), the Environment Protection Standards unit has developed a joint Search and Rescue/Oil Spill Trajectory Model (SAR/OSTM) technical specification. The specification system provides for the provision of near real time meteorological and oceanographic data as well as drift and trajectory modelling capabilities for Australian waters.⁽²⁾ The project is called the Net Water Movement project and was split into two main phases and incorporates several major software developments in meteorological and oceanographic (metocean) modelling.

The successful tenderer was a consortium headed by the Australian Bureau of Meteorology, Special Services Unit. The consortium includes the National Tidal Facility, CSIRO Marine Laboratories and the Applied Science Associates (ASA-Asia/Pacific) who have provided the OILMAP modelling software and Global Environmental Modelling Services (GEMS) who have provided GCOM3D, a 3-dimensional continental shelf hydrodynamic model.

Phase 1 of the project has been completed and the GCOM3D/OILMAP system is in place for the National Plan. This system now provides state-of-the-art modelling of water movement (hydrodynamics) in the coastal continental shelf region of Australia not affected by ocean circulation currents as well as the trajectory modelling oil spills.

From an oil spill response perspective, the primary area of interest is Australia’s coastal regions, whereas from a marine search and rescue perspective a much wider area needs to be covered by a drift model. The present Australian SAR area of responsibility is depicted in Figure 1 and corresponds to one-ninth of the world’s ocean surface.

Figure 1 – Australia’s Economic Exclusive Zone (EEZ in red) and designated

Maritime Search and Rescue (SAR area brown).

On the continental shelf the major forcing mechanisms on water movement are predominantly tidal and meteorological eg winds. Off the continental shelf in deeper waters the influence of tides diminishes greatly and the dominant forcing is thermodynamic and meteorological producing more geostrophic currents. The continental shelf, in some areas, are also affected by these open ocean currents and thermal effects, for example the East Australian Current and Leeuwin currents off Western Australia.

The second and main phase of the Net Water Movement project involves the development of near real time access to a vast array of land based, in-situ and satellite derived oceanographic and meteorological data. This information will cover all Australia’s territorial waters, the Australian EEZ as well as the entire Australian Search and Rescue area of some 47 million square kilometres. ^(1,3)

Data inputs including direct data feeds to the AMSA SAR/OSTM model will include;

- high resolution bathymetric data sets for selected high risk regions

- tidal amplitudes and phase constants across the complete SAR region

- sea surface winds (actual and forecast)

- outputs from the Bureau’s global and regional weather models

- altimeter data from the Topex-Poseidon satellite

- deep ocean current data base from CSIRO

- satellite derived sea surface temperatures from NOAA satellites

- inputs from real time tide gauges where available etc^.(1)

Phase 2 of the OSTM/Net Water Movement project which will incorporate the automatic feeding of metocean data from the Bureau of Meteorology’s systems to the AMSA computer network is scheduled for completion in late 2000 early 2001.

GCOM3D - Hydrodynamic Model

GCOM3D is a 3 dimensional ocean model developed by GEMS to study and predict water movement on or near the continental shelf of Australia. This system has only been made possible due to a better understanding of oceanography and because of the speed and versatility of modern desktop PCs^.(4)

The model simulates the tidal and wind forced flow in the region of interest for a user specified grid. Underlying the model is regional bathymetry data and tidal constituents. For coastal waters the spacing for vertical grids is in metres and horizontal spacings are in kilometers. An Australian wide digital grided 30 second arc bathymetry data set was provided by the Australian Geological Survey Organisation (AGSO) and is being supplemented by more accurate bathymetry from State/NT maritime and port authorities where provided. An example of the extent of the existing bathymetry data is given in figure 2.

Figure 2 Extent of 30 second arc grided bathymetry data for GCOM3D used in hydrodynamic water modelling.

GCOM3D is a locally developed numerical model and is now used by a number of oil production and exploration companies in Australia and sold internationally. An example of the output of the model is shown in Figure 3 for the GCOM3D model run for the Port Lincoln region of the Spencer Gulf in South Australia. The output is interfaced directly with the OILMAP software reading generated currents and can be animated over selected time periods to observe the predicted current strength and direction over the grid region.

Figure 3. Example of output from GCOM3D for the Port Lincoln region SA

OILMAP – Spill Trajectory and Oil Weathering Modelling.

OILMAP was developed by ASA in the US and provided locally by ASA Asia Pacific. It provides rapid, accurate and user friendly information on oil movement, ie. direction, speed, weathering, fate and spreading characteristics. ^(5,6)

Combined with the currents generated by GCOM3D for the region of interest it provides the ability to predict oil impacts on shorelines and quantitative estimation of oil breakdown and weathering using up-to-date and validated algorithms.

The features of the AMSA OSTM (GCOM3D/OILMAP) system allows the operator to:

· Specify spill scenarios anywhere in Australian waters

· Display spill trajectories over time intervals selected by user

· Grid any area within the geographic location for model operation

· Allow allocation/editing of foreshore type for oil/shoreline interaction

· Manual input or automatic import of wind speed/direction

· Generate currents over time for continental shelf regions of Australia (for regions not impacted by ocean circulation currents)

· Animation of currents (vector direction/strength) over time period

· Enter and edit oil types in the oil library

· Display natural resources impacted by the oil and measure extent of shorelines impacted by oil.

The OSTM model provides the:

· Prediction of weathering and surface/sub surface transport of oil slicks

· Prediction of the probability of key coastal/marine areas being impacted from a given site

· Backtracking of the model to determine the likely spill site position

· Updating of predictions with overflight data at spill scene

· Incorporation of boom-oil interaction

· Plotting of spill dispersant application zones

· Performing risk assessments for important shorelines and environmental resources

· Use of NOAA’s ADIOS oil database of nearly 1,000 oils for weathering calculations and also the incorporation of chemical/physical properties of oils produced and imported into Australia.

The oil spill model predicts oil trajectories for either instantaneous or continuous release spills and includes algorithms for spreading, evaporation, emulsification, entrainment, oil-shoreline interaction, and oil-ice interaction. The oil's distribution and mass balance are predicted for the type of oil spilled. Model predictions may be up-dated to agree with observed oil locations. Barriers may also be added to implement simple booming strategies, and dispersant may be applied to simulate dispersant application. ⁽⁶⁾

OILMAP provides the ability to instantaneously modify the spill scenario based on overflight information by adding GIS polygons that represent oil observations. This may also be implemented by importing observations based on remote-sensed data or GPS locations.

Figure 4 is a typical screen output from the OILMAP software for a scenario in the Spencer Gulf near Port Lincoln of a spill of a medium grade crude oil over a 24 hour period. The system allows animation of the spill trajectory and display of prevailing/predicted winds, oil weathering and fate, and shows oil/shoreline impact (in red).

Figure 4. Spill Trajectory output from OILMAP showing area swept by oil and shoreline impacts, wind direction and oil fate for a hypothetical spill scenario in Spencer Gulf, SA.

OILMAP can also be run in the Receptor Mode which is essentially running the model backwards in time. This allows the user the ability to backtrack ‘mystery’ oil slicks that may appear on coastlines or calculate the time of impact of a spill on a particular area of slicks at sea.

The Stochastic mode is forward looking and is mostly used for contingency planning and provides multiple spill trajectories over time eg annual/seasonal/monthly currents and winds for a region. It provides a probability distribution of the likely movement and shorelines impacted for selected locations.

Provision of Oil Spill Trajectory Model Outputs for the National Plan

The OSTM system is based at AMSA’s headquarters in Canberra with a number of personnel trained to provide 24 hour a day support to the National Plan. The model can also be run on site during incidents if required by National Response Team (NRT) personnel. This provides the ability to re-run the model with regular updates from field observations of slick locations, and quantities of oil at sea from surveillance flights. Regular and accurate updates of local wind speed and direction helps refine the scenario thereby improving the modelling of slick trajectories and likely impact zones.

An OSTM request proforma has been placed on the AMSA Internet web site to allow Port, State, Territory and industry organisations to access and complete the necessary information to run the model for any incident. This form can be completed and the information provided verbally, faxed or emailed to AMSA.

The location of the OSTM proforma and instructions is at…

http://www.amsa.gov.au/me/natplan/toolbox/Ostm/Proforma.htm

The output from OSTM can be provided verbally over the phone to the requesting organisation, by hardcopy and fax, down loaded from the AMSA FTP site or by email attachment in a compressed format to an individual or response centre. It is preferred that requesting organisations provide an email address as the ability to use the full extent of data by the user is enhanced considerably and avoids fax system overload in control centres during emergencies.

Tools have been developed by AMSA and provided to all States and the NT in the Oil Spill Response Atlas to automate the import of the email attachment and overlay of the trajectory model in the user operated OSRA GIS on site or in the Incident Control/Command Centre. This allows the animation and visualisation of the spill/slick movement and more accurate geo-referencing. Other information can be overlayed to provide likely resource impacts during the incident.

The Oil Spill Response Atlas - Geographic Information System

Background

When an oil spill occurs at sea or in coastal waters the other major concern of responders is; - what environmental impact will the oil have? That is, what coastal and marine environmental resources may be at risk from the spill?

Coastal and marine resource atlases, in a computerised Geographic Information System (GIS) form, are an essential tool in contingency planning and in decision making during marine pollution incidents. They provide a quick and efficient means of determining marine and coastal areas of environmental, economic and strategic sensitivity that could be impacted in the event of an oil pollution incident, and also provide valuable resource and logistical information for combat authorities.

On the 12^th of August, 1998, the Federal Environment Minister, Senator Hill, announced the allocation of $1 million under the Natural Heritage Trust AMSA to fast track the production of a computerised Oil Spill Response Atlas for Australia, due for completion in December 1999. The National Oil Spill Response Atlas (OSRA) project, managed by AMSA on behalf of the National Plan and in conjunction with the States and Northern Territory, focused primarily on fast tracking data collation, data capture, the digitisation and integration of the diverse environmental atlases into a uniform and consistent National GIS for use during maritime oil and chemical spill incidents. ^(7,8)

The major outcome of the OSRA project was to produce an integrated and uniform spill response atlas for Australia in a computerised GIS format able to be conveniently accessed and operated by spill response organisations, planning and clean up teams, environmental and wildlife agencies and other emergency organisations^{. (7)}

Australia is not alone in this trend towards the use of GIS technologies in marine pollution management. Integrated GIS based spill response systems have also been developed internationally with the US, Japan, Korea and the UK having fully operational decision support systems. ^(9,10,11,12)

OSRA Project Aims and Objectives

The Australian OSRA program’s prime aim was to systematically compile all relevant geographic and textual data into a standard GIS format for the majority of Australia’s maritime and coastal environments. This will assist planners to identify resources at risk, allow quick assessment of response priorities for protection or clean up.

National OSRA datasets include:

· biological, environmental, wildlife and man-made resources present Australia wide,

· geomorphological mapping and shoreline sensitivity to oil spills,

· human-use resource considerations,

· logistical and infrastructure information to support a spill response.

As a priority, only the identified high risk areas of the coastline for oil spills have been covered systematically under OSRA and other regions of Australia to varying degrees. These high risk areas were selected on the basis of the:

- history of oil spills

- shipping density

- navigational hazard and

- high environmental sensitivity.

An on-going development plan is being developed to support the OSRA project to ensure over the next few years the other regions of the Australian coastline are covered in the GIS.

OSRA Project Development and Data Sets

The OSRA project provided the ability to undertake a coordinated process of data collection and sharing nationally of both environmental and infrastructure information. A national specification was developed for OSRA along with a data dictionary and data management guidelines. The process was guided by a multi agency Steering Committee and followed a series of user workshops in each State and the Northern Territory to determine required data sets and operational functionality. The project success was primarily a result of the excellent collaboration and professionalism of many agencies and organisations involved in the National Plan arrangements. ⁽¹³⁾

The OSRA GIS includes maps, charts, satellite imagery, point, line and polygon digital data as well as databases and textual information in a user friendly point/click format. A GIS provides an efficient storage, retrieval, analysis and display of environmental and resource information to support a range of users in oil spill operations and planning. The user loads and displays only that information necessary for supporting decisions in the region of the incident and at whatever scale the user requires. Data sets that have been acquired and collated for the OSRA GIS include, but not restricted to, the following:

- habitats both coastal and near shore marine

- high definition coastlines

- bathymetry contours for selected depths

- nautical charts in scanned georeferenced format

- scanned topographical charts for all of Australia (100K)

- marine parks, reserves and national parks

- biological resources and conservation status

- fisheries & aquaculture

- coastal & marine wildlife resources

- recreational resources

- locations of National Plan equipment stockpiles

- aerial photography for selected regions

- National LandSat remote sensing (colour 50m)

- oblique photography linked geographically for selected regions

- high resolution SPOT imagery for all harbours, ports and marine parks

- landmarks and features

- shoreline access and roads

- airports, marinas and boat ramps

^- logistic and other infrastructure information. ⁽⁸⁾

In figure 5 a screen dump of a typical output from OSRA for the Hinchinbrook region of Queensland showing the locations of mangroves, seagrass beds, dugong sightings and turtle feeding areas overlayed on a LandSat image of the region.

Figure 5 OSRA output for selected environmental data for Hinchinbrook Island region, Queensland.

In figure 6 an OSRA screen output has been reproduced for the Port Lincoln area showing a hypothetical spill used in figure 4 and overlayed on a satellite image, with the locations of significant sea bird colonies near the spill site. Icons representing a specific sea bird colony can be ‘clicked’ and a database on species, numbers, protection status and seasonal aspects can be accessed.

Figure 6. South Australian OSRA systems overlayed on a satellite image, with the locations of significant sea bird colonies near a hypothetical spill site Port Lincoln area.

In figure 7 an output from the South Australian OSRA project shows selected infrastructure layers including access roads, airports, boat ramps, bathymetry overlayed on a high resolution SPOT image for the Port Lincoln region.

Figure 7. Selected OSRA infrastructure layers, Port Lincoln region South Australia

AMSA on behalf of the National Plan has obtained from the Hydrographer the complete Australia wide set of scanned and GIS ready nautical charts. This also includes those AUS nautical charts available for off shore and remote Islands and Territories. An example of the incorporation of offshore and foreshore information eg reefs, mangroves and sea grass beds over a scanned nautical chart of the Whitsundays Islands is shown in Figure 8, along with the position of a hypothetical oil slick from field reports during Exercise Cumberland in Queensland.

Figure. 8 OSRA output using a nautical chart overlayed with environmental information and reported slick position for Exercise Cumberland.

High resolution SPOT satellite imagery for all major ports, harbours and environmentally significant areas of the Australian coast has been obtained from ACRES and loaded onto the OSRA system in Canberra. An example of the detail obtained in the high resolution SPOT satellite imagery is shown in figure 9 which is a segment of one image tile of the entrance to Brisbane River Queensland. The offshore, foreshore landmarks are well defined and can be overlayed with environmental or response information.

Figure 9 Example of the detail available in the SPOT imagery for Brisbane River.

Applications of the OSRA system to Marine Pollution Response and Planning

The OSRA GIS has been designed to be portable for operation in the field or for use in operations rooms and command centres. The software is modular and further data sets and functionality can be added to the system and refined to meet the changing needs of users. An on-going development and data maintenance plan is being developed to support the OSRA development for Australia.

OSRA development agencies have also provided non-restricted environmental layers for distribution through the Australian Coastal Atlas (ACA) State/NT Internet computer nodes provided by the Environmental Resource Information Network (ERIN). OSRA is currently being linked with AMSA’s maritime search and rescue and spill trajectory models as well as emergency contact lists and other decision support systems.

The OSRA GIS can be used for managing information related to pre spill contingency planning, during a spill and for post spill environmental damage assessment. An incident specific spill response plan can be developed more effectively without the need to have to scout the area to determine resources under threat, or sift through multiple and different scale maps, charts, hardcopy atlases and directories to find information required. By assessing OSRA information quickly, responders will become familiar with the geographic layout of the area, it’s environmental resources and imperatives, natural features, access and logistic problems before arriving at a site. Or when responders have to make planning decisions remote from the incident site. The OSRA system can be used for a variety of purposes including;

- preparing site/regional contingency plan maps

- help determine protection plans for shorelines

- assess habitats affected or likely to be affected by the spill

- determine species likely to be impacted by marine pollution

- measure affected shorelines

- present visually response strategies and clean up operations

- environmental monitoring data management

- calculate area of slicks from field GPS readings or landmarks

- keep an historic record of equipment locations and deployment.

In the US and Canada, GIS based spill response systems have been successfully linked to Incident Command Systems (ICS) as well as shoreline assessment and treatment databases like SCAT and providing valuable clean up and spill command and control document management. ^(14,15)

For OSRA to be successfully utilised during an incident, adequate resources must be allocated to its operation to provide 24 hour decision support for spill planners. The use of the OSRA GIS during incidents is provided on a State by State basis with operators trained in each jurisdiction and under the management of the State Incident Controllers and with the ability to bring in further GIS operational support from AMSA or interstate during an extended or prolonged response under National Response Team arrangements.

OSRA Functionality and Automation Tools

AMSA has recently completed a series of OSRA automation tools and has provided prototypes to States/NT agencies for evaluation purposes. These OSRA GIS automation tools include:

- incident manager

- locate incident

- spill manager (OSTM import)

- spill trace manager

- OSRA theme manager

- time/distance to nearest feature (impact analysis)

- event logging

- enter shape/location

- OSRA map generator.

The “Incident Manager” assigns a unique identifier and file structure to store the information generated by OSRA and also user inputs.

A “Locate” tool allows a lat/long or place name (Gazette search) to locate an incident across Australia. An example of the tool is shown in figure 10.

Figure 10 OSRA tool “Locate incident/spill” for Australian waters