ENVIRONMENTAL SERVICES
overview

Natural systems are complex, heterogeneous and diverse, and every aquatic ecosystem is unique with many variables co-existing and providing feedback to this complex system. The study of these many co-occurring and interacting physical, chemical and ecological processes in a dynamically changing environment cannot be easily simulated or studied in conventional field and laboratory experiments.

Water Technology has an extensive and complimentary range of technical skills to provide a variety of environmental services from the catchment to the sea. Our multidisciplinary team are adept in the design and implementation of monitoring and modelling programs for water quality, contaminant tracing, erosion severity, vegetation establishment to improve ecological health of any aquatic system.

We combine leading edge technology with out-standing project experience to deliver economic and environmentally sustainable solutions.We pride ourselves in the creation of innovative solutions to technical environmental issues. We have been involved in the technical work and development required for numerous Environmental Effects Statements (EES), Environmental Impact Assessments (EIA), Environmental Management Plans (EMP) as well a range of other projects culminating in effective and sustainable environmental management solutions.

Capabilities
  • Contaminant modelling
  • Nutrient load management
  • Sedimentation studies
  • Dredging impact assessments
  • Water quality forecasting
  • Hydrological/hydraulic analysis
  • Eco-hydraulics
  • River Stability Assessment & Design
  • Environmental Flow Assessment
  • Monitoring Program Design & Implementation
  • Water Quality Monitoring and Modelling
  • Agent Based Modelling for Fish Response
  • Algal Bloom Modelling and Management
Client:
Tenax Energy
location:
Bohol Sea, Philippines

Philippines Tidal Power Assessment

Water Technology generated a calibrated numerical model of the Bohol Sea in the central Philippines to assess potential locations for tidal power generators. High current streams intersect the islands of the Philippines through the Bohol Sea and the project was designed to provide a rapid evaluation of the site based on a number of criteria provided by the Client.

Data used for the assessment was captured from global tidal models and C-MAP navigational charts. A number of locations were identified through the study and more detailed assessment of the current speeds and potential for tidal power explored through refined modelling and investigation.

Client:
CQG Consulting and FTP Pty Ltd
location:
Central Queensland

Fitzroy Terminal – Hydrodynamic and Sediment Transport Impact Assessments

Located in Central Queensland, south of Rockhampton, the proposed coal export terminal required marine operations to comply with the strict guidelines and authority of Maritime Safety Queensland (MSQ), the Australian Maritime Safety Authority (AMSA) and the Great Barrier Reef Marine Park Authority (GBRMPA).

Water Technology was engaged by CQG Consulting and FTP Pty Ltd to conduct a coastal environments EIS for the proposed coal export terminal within Raglan Creek. A range of data collection and environmental risk assessments as part of an EIS submission were undertaken, of which, a significant portion included the assessment of the hydrodynamic and sediment transport impacts associated with the dredging of a navigation channel and swing basin, which was also designed by Water Technology. The data collection included water levels, waves and currents both offshore and within the Fitzroy River.

The hydrodynamic impacts were assessed through the development of a calibrated hydrodynamic model of Raglan Creek and Keppel Bay of existing conditions, which was then modified to include the designed navigation channel and swing basin. The numerical model was used to assess tidal water levels, currents, extreme storm events, water quality, the impact of oil and coal spill events, port design, climate change assessment and dredging methodology reviews. The extent of the model allow cyclones to be simulated across the region and the impact on water levels and wave height to be established at the site. As an additional feature of the project, the impact of increased vessel travel within the Fitzroy River was simulated within the hydrodynamic model and the subsequent ship swash on the sensitive mangrove banks determined.

The dredge induced suspended sediment plume associated with the dredging of the channel and swing basin were also assessed though the calibration and application of a 3D suspended sediment transport model, which simulated the timing and movement of a cutter suction dredge. The long term change sediment transport and sedimentation within Raglan Creek and the navigation channel were also assessed, and suggestions made for future maintenance dredging.

Key Services Provided

  • 2D & 3D Hydrodynamic Modelling
  • 2D & 3D Sediment Transport Modelling
  • Dredge Plume Modelling
  • Dredge Channel and Swing Basin Design
Lake Kutubu, PNG
Client:
Papua New Guinea Liquefied Natural Gas
location:
Southern Highlands, Papua New Guinea

Condensate Spill Fate and Transport (PNG)

In the Southern Highlands of Papua New Guinea, a natural gas (condensate) pipeline links the Hides Gas Condensate Plant and the Central Processing Facility.  It was anticipated the pipeline would traverse four major rivers and six lesser watercourses and numerous minor watercourse crossings.  The length of the pipeline is approximately 109 km and includes steep terrain, regions of high rainfall and flooding, and sensitive cultural areas and ecological habitats.

As part of the mitigation planning, and in the event of a release of condensate to surface waters along the pipeline, an understand of the impacts and transport through the local environment was required. Water Technology was engaged to undertake condensate fate and transport modelling for the Papua New Guinea Liquefied Natural Gas (PNG LNG) pipeline project at Lake Kutubu, and the waterways along the pipeline route. The modelling assessed dilution and volatile losses, the spill effect and surface water drainage pathway flow duration, with the results were used to provide information for the development of site specific spill response plans.

The modelling considered condensate loss to the atmosphere, residence within the water column and the formation, and maximum size, of the condensate plume at the water surface.  To do this, the condensate was modelled separately in the near-field and far-field.  The reason for modelling these zones separately was to enable an understanding of the dynamics of a spill plume both close to the spill location and as it is transported further downstream.  The focus of the near-field modelling was on the geometry and dilution characteristics of the initial spill mixing zone, while the emphasis of the far-field modelling was to track the spill plume as it is transported away from the spill site by the flow.

The modelling involved detailed assessment of near-field plume mixing using the package CORMIX, coupled with extensive 1D models (MIKE  11) of the river network in the Southern Highlands.  The lake was modelled in 2D (MIKE 21) in order to describe the lake hydrodynamics and mixing in more detail.  Based on the outcomes of the modelling a toxicology assessment was undertaken to describe the potential ecological effects and potential impacts of any condensate spill.

Key Services Provided

  • Hydrological Assessment
  • Near-field and far- field spill and transport modelling
  • 1-D and 2-D Hydrodynamic modelling
Huntly Power Station
Client:
Genesis Energy
location:
Waikato, New Zealand

Huntly Power Station (NZ) – Hydrodynamic Modelling

Huntly Power Station is the largest thermal power station in New Zealand and is situated on the banks of the Waikato River in Huntly. The original four generators were built between 1973 and 1985, and upgraded with a gas turbine plant in 2004. A further upgrade in 2007 increased the station’s production of power from an original 1000 megawatts (MW) of electricity to 1485 MW. The station supplies about 17% of the country’s electrical power.

Water Technology was commissioned by the Genesis Energy to develop both a near field (3D) and a far-field (2D) hydrodynamic model of the Waikato River at the Huntly Power Station. The modelling investigation was undertaken in order to more accurately describe the Station outfall discharge plume and to gain an understanding of the fate of chemicals discharged with the Station cooling water. The models were used to undertake scenario modelling of the Station cooling water outflows and various discharge chemical concentrations for a range of river flow conditions, with a view to informing improved management decision of the Station operation and the assessment of performance against Resource Consent conditions.

A detailed bathymetric description of the river from upstream of the Power Station to approximately 5km downstream was developed, which can be enhanced in future with improved survey information. The model was calibrated to local conditions and the 3-dimensional model used to assess the initial mixing of the heated water from the power plant. The model was used to inform the power station operators of the current dilution and transport of process waters with river flows, particularly under low flow conditions, which are critical to operation of the station under their Resource Consent conditions. The models can also be further developed to describe sediment transport conditions and the effect of existing Iowa Vane structures upstream of the outfall.

Key Services Provided

  • Hydrodynamic Modelling—2D and 3D
  • Advection-Dispersion modelling of the discharge plume and discharge chemicals
  • Assessment of discharge chemical fate
Project Sea Dragon
Client:
Seafarms Group
location:
Northern Territory, Australia

Project Sea Dragon (Northern Australia) Data Collection

Project Sea Dragon is a large-scale, integrated, land-based prawn aquaculture project in northern Australia designed to produce high-quality, year-round reliable volumes for export markets and will ultimately be one of the largest prawn farming operations in Australia, if not the world. Project Sea Dragon will be a staged development of up to 10,000 hectares of production ponds, including the development of a series of facilities across northern Australia.

Water Technology’s roles in the Project Sea Dragon EIS project included significant field and data collection work in the waters around Darwin and Legune Station. Field work has included mobilisation, deployment and retrieval of monitoring instruments and the subsequent analysis of oceanographic, hydrologic, meteorological and sediment data. Bathymetric survey and ADCP current data has been both collected by Water Technology and Project Managed by Water Technology for a number of the project locations.

The isolated and remote location of the project sites required Water Technology staff to be innovative and adaptable to a range of conditions to ensure data was collected. The suite of data collected for the project provided a robust set of data which was used for model calibration and to provide additional information to the environmental characteristics of the site.

Waterlines

Snow Creek Weir Mitta Mitta
Client:
North East Catchment Management Authority
location:
Mitta Mitta, Victoria

Snowy Creek Weir Fishway Passage

The Snowy Creek Weir was constructed across Snowy Creek in the 1970’s to provide a swimming hole for the local community. The weir is recognised as an important asset to the local community, drawing tourists who make use of the swimming area and complementary facilities and services. However, the Snowy Creek Weir is also known to impact on the movements of fish within Snowy Creek. Provision of fish passage through the Snowy Creek weir structure would allow fish passage through the entire Snowy Creek system as there are no other man-made barriers present.

 

Snowy Creek Fishway - Bathymetry Snowy Creek Fishway - Current Speed Snowy Creek Fishway - Surface Elevation Snowy Creek Fishway - Total water depth

Paper – 13th Hydraulics in Water Engineering Conference – Improving fishway design through the use of detailed 2D and 3D hydrodynamic modelling (PDF)

 Key Services Provided:

  • 2-D and 3-D hydrodynamic modelling
  • Fishway assessment and design

 

Client:
Seafarms Group
location:
Northern Territory, Australia

Project Sea Dragon (Northern Australia) Numerical Modelling

Project Sea Dragon is a large-scale, integrated, land-based prawn aquaculture project in northern Australia designed to produce high-quality, year-round reliable volumes for export markets and will ultimately be one of the largest prawn farming operations in Australia, if not the world. Project Sea Dragon will be a staged development of up to 10,000 hectares of production ponds, including the development of a series of facilities across northern Australia.

Water Technology completed numerical modelling for the Project Sea Dragon EIS study in 2016-2017. The numerical modelling was a complex task involving a regional model extending 200km offshore across the Joseph Bonaparte Gulf, upstream into the project site to include tidal channels less than 10m wide and across the project site where a tidal floodplain 30km wide was subjected to twice daily inundation.

This far field 2-dimensional numerical model was coupled with a localised 3-dimensional model to simulate the discharge from the prawn farm. The 3-dimensional discharge model simulated tides with a range of 9m across a 1km wide creek which came close to completely drying during the low tide and had depths of water in excess of 10m on the high tide. The 3-dimensional model was used to illustrate the rapid mixing of the discharge in these super tidal waters where currents speeds were in excess of 2m/s and the bed form and banks were constantly evolving. Sensitivity testing was completed to provide dilution was consistent in the discharge creek despite the moving channel.

A CORMIX model was established to confirm the rapid moving at the discharge, with the dilution tested over a matrix of water level, current and discharge rates.

Waterlines Summer 2017

Client Website: seafarms.com.au/about-project-sea-dragon

Key Services Provided

  • Data collection and other site environmental monitoring activities
  • 2-D and 3-D numerical modelling of hydraulic and water quality processes
  • Coastal process and bank erosion assessments
  • Storm surge and cyclone inundation assessments
  • EIS related assessments and project design assistance
McQuades Bend Crossing after fishway passage complete
Client:
North East CMA
location:
Warby-Ovens National Park

Completed Fishway Passages at McQuades Bend and Frost Crossing, Ovens River

Video: North East Catchment Management Authority

The Warby-Ovens National Park, 240 km north east of Melbourne and 10 km west of Wangaratta provides an important connection between the alpine foothills, the Murray River and floodplain. In 2012, two entry points to the Warby-Ovens National Park were impacted by flooding. The gravel and rock crossings at McQuades Bend and Frost Crossing required upgrading, this presented an opportunity for the North East CMA to improve the waterway connectivity for fish as the crossings were a barrier to fish migration.

Water Technology, working in conjunction with Gordon Gibson Nominees and the Arthur Rylah Institute, was involved in the preparation of detailed design plans for the construction of the fishways, all the relevant approvals and construction to enable fish passage at Frosts Crossing and McQuades Bend Track at low flows, across the Ovens River floodplain.

The objectives of the project were to provide:

  • Improved fish passage and floodplain connectivity at low flows at Frosts Crossing and McQuades Bend Track.
  • Detailed design and construction to enable fish passage at low flows across the Ovens River floodplain at the two project locations.
  • An improved crossing arrangement on Frosts Crossing and McQuades Bend Track that minimises the alteration to flow characteristics surrounding the crossing, minimises erosion potential surrounding the crossing, minimises maintenance requirements and provides for fish passage in consultation with Parks Victoria.
  • Construction, site layout and supervision for both fishways at Frosts and McQuades Crossings, to be carried out in consultation with North East CMA and Parks Vic.
Before fishway After fishway construction
McQuades Bend McQuades Bend Crossing Before McQuades Bend Crossing after fishway construction
Frost Crossing Frost Crossing before fishway Frost Crossing after fishway construction

An article on these crossing is available in Water Technology’s Waterlines

In the news:

 


River regulation and the presence of instream barriers are known to impact natural river processes and the movement of fish. This can produce environmental conditions that benefit some of the most invasive species on the planet, such as the common carp, and interrupt natural migratory and breeding cycles of native fish.

The Murray-Darling Basin (MDB) in eastern Australia has over 3,600 instream barriers, which generally consist of dams, weirs, and flow regulators. Recognising the impacts of these barriers on native fish, the Murray-Darling Basin Authority (MDBA) instigated a fishway construction program (the Sea to Hume program) in 2001 to mitigate the impacts of major instream barriers on fish movement. This ambitious program has now re-established longitudinal connectivity to some 2,235 km of the Murray River, catering for the migration of native fish species within the MDB.

Catchment Management Authorities, water authorities and councils are now working towards a similar goal, to re-establish longitudinal and lateral connectivity at instream barriers within their respective jurisdictions. The North East CMA specifically is aiming to improve fish passage at a number of instream barriers by constructing fishways and fish friendly structures to facilitate passage along the Ovens and Mitta Mitta Rivers. Both riverine systems are known for their recreational fish species, such as brown trout, Murray cod and golden perch, all of which require unhindered movement to complete various aspects of their life-cycle. These riverine systems also harbour threated species such as Trout Cod and Macquarie perch, while Blackfish and various Galaxias species are also present.

Water Technology has designed fishways at three locations on the Ovens River (Tea Garden Weir, Frosts Crossing and McQuade’s Bend crossing) and one on the Snowy Creek at Mitta Mitta. The development of the designs required Water Technology to work in multidisciplinary teams and consult with local communities to ensure that their needs are also met with the design of the fishways.

Ovens River Tea Gardens Weir
Client:
North East CMA
location:
Ovens River at Tea Gardens Creek

Ovens River Fishway Design at Tea Gardens Creek Weir

River regulation and the presence of instream barriers are known to impact natural river processes and the movements of fish. This can often facilitate environmental conditions that benefits some of the most invasive species on the planet i.e. common carp and interrupts the natural migratory and breeding cycles of native fish.

The Murray-Darling Basin (MDB), in eastern Australia, has over 3,600 instream barriers which generally consist of dams, weirs, and regulators. Recognising the impacts of these barriers on native fish, the Murray-Darling Basin Authority (MDBA) instigated a fishway construction program (termed the Sea to Hume program) in 2001, designed to mitigate the impacts of major instream barriers on fish movement. This ambitious program has now re-established longitudinal connectivity to 2,235 km of the Murray River, catering for the migration of native fish species within the MDB.

Similarly, Catchment Management Authorities, water authorities and councils are now working towards a similar goal, to re-establish longitudinal and lateral connectivity at instream barriers within their respective jurisdictions. The North East CMA specifically, is aiming to improve fish passage at a number of instream barriers by constructing fishways and fish friendly structures that facilitate passage along the Ovens and Mitta Mitta Rivers. Both riverine systems are known for their recreational fish species, such as brown trout, Murray cod and golden perch, and all require unhindered movement to complete various aspects of their life-cycles. These riverine systems also harbour threatened species such as trout cod and Macquarie perch, while blackfish and various galaxias species are also present.

Ovens River Tea Garden Creek Weir Fishway Design

The Tea Gardens Creek Weir on the Ovens River delivers irrigation, stock and domestic water to entitlement holders on the Tea Garden Creek system. The weir is owned and operated by Goulburn Murray Water and was updated in 2016 to extend the weirs operating life and support their water supply objectives. While the update in 2016 met distribution needs it remained a barrier to fish movement.

It was identified that a fishway was required to improve fish connectivity end ecological function. The new fishway design was required to meet the following core criteria:

  • Achieve fish passage without compromising weir functionality
  • Meet with Goulburn Murray Water and community needs regarding safety in design
  • Be resilient to flood events (including total submersion)
  • Minimise future maintenance requirements; and
  • Where the final design allows, include provision for PIT-tag reader installation for monitoring fish movement through the structure.
Before Rock Ramp Fishway Design
Teas Gardens Fishway Ovens River Tea Gardens Weir Fishway Design
Ovens River,  Tea Garden Creek Weir.  Ovens River, Tea Gardens Weir
Water Technology has design a partial width rock ramp
fishway to replace the right side of the weir.

Water Technology has designed fishways in three locations on the Ovens River (Tea Garden Weir, Frosts Crossing and McQuades Bend crossing) and one on the Snowy Creek at Mitta Mitta. The development of the designs required Water Technology to work in multidisciplinary teams and consult with the local communities to ensure that their needs are also met with the design of the fishway.

Working on these projects Water Technology has utilised the following skillsets:

  • Waterway Engineering
  • Fluvial Geomorphology
  • Vegetation Ecology
  • Fishway Detail Design
  • Project Management
  • Community Consultation
Amity Point, North Stradbroke Island, QLD
Client:
Redland City Council
location:
Amity Point, North Stradbroke Island, Queensland

Shoreline Erosion: Aligning management strategies with community aspirations

Main image: Rodney Wiley

Located on the north-west corner of North Stradbroke Island, the township of Amity Point enjoys a rich diversity of seascapes and landscapes – providing extensive recreational and lifestyle opportunities that are considerably enhanced by local cultural, heritage and environmental values.

The historical development of Amity Point has focused on the shoreline – as residents and visitors seek to enjoy the unique character of this coastal precinct. However, the dynamic nature of the coastal environment means that local foreshores are experiencing erosion which is threatening these values, as well as endangering essential infrastructure.

Water Technology was engaged by Redland City Council to develop the Amity Point Shoreline Erosion Management Plan which included a framework for the sustainable use, development and management of this vulnerable foreshore that was acceptable to both the residents and the relevant management authorities.

Previous recommended approaches to shoreline management at Amity Point (including an earlier SEMP completed by another consultant in 2014) did not allow for Council and the local Amity Point community to appropriately and proactively plan for suitable erosion management along the vulnerable foreshore.

This project therefore focused on developing an approach that was consistent with the community aspirations and the polices of the Commonwealth and State Governments, and Redland City Council. Technically, the Shoreline Erosion Management Plan considered various strategies in response to the erosion processes and associated risks at Amity Point and, importantly, it involved considerable engagement with the local community and other stakeholders, and has delivered a unique solution to the considerable erosion hazard at Amity Point.

Amity Point by Rodney Wiley

Amity Point by Rodney Wiley

Key Services Provided:
  • Physical Process Analysis
  • Erosion Threat Risk Assessment
  • Shoreline Erosion Management Plan
  • Stakeholder Consultation and Engagement
  • Shoreline and Erosion Management Optioneering and Recommendations

Presentation by Paul O’Brien (Water Technology) and Tim Mitchell (Redland City Council)
at the 6th Queensland Coastal Conference 2017 (5-7 September 2017).

Client:
West Gippsland CMA
location:
Gippsland Lakes, Vic

The Latrobe River estuary is located at the interface between the Latrobe catchment and the Gippsland Lakes. It is a part of the Gippsland Lakes complex, recognised as a wetland of international significance. Upstream freshwater reserves have been set aside for ecological flows, but the environmental flow requirements were unknown. The water resources are also shared between agricultural, industrial, and domestic use. Water Technology was engaged to address the gap developing environmental flow recommendations for the lower Latrobe River estuary.

1D and 3D models were developed to characterize the hydrodynamic regime of the estuary. The 1D model represented river and floodplain flows and was used to examine the interactions between the river and the floodplains. The 3D model was used to provide more detailed information about the hydrodynamic properties of in-stream flows, including interactions between flows, lake levels, and salt wedges.

Client:
In collaboration with: University of Melbourne & University of Western Australia
location:
Gippsland Lakes, VIC

Ecological and water quality experts from Water Technology and Monash University joined forces to assess the water quality and ecological processes of the Gippsland Lakes.

The Lakes have suffered recurrent summer toxic blooms of cyanobacterium Nodularia spumigena since 1985. Diatoms and dinoflagellates also commonly form blooms in the Lakes. Nodularia has the ability fix free nitrogen and is typically found during periods of low freshwater inflows in brackish waters near the inflowing rivers. Growth of Nodularia is controlled by a combination of biological, chemical and physical drivers which are impossible to simultaneously assess through physical experiments.

Whilst the key drivers of the growth of Nodularia (intermediate salinity, stratification, bottom water hypoxia and sediment phosphorus release) are well understood, there was a lack of quantitative tools to predict bloom formation and assess management options to mitigate them.

A 3-D fully coupled hydrodynamic biological ecological model was used to explore the interaction between the physical and biogeochemical controls over Nodularia blooms. The hydrodynamic model included turbulent mixing within the water column, whilst the ecological component of the model contained over 40 state variables and 200+ processes, parameterised by 176 constants to describe the biological/ecological and chemical reactions occurring in the water column and sediment compartments.

Client:
Groote Eylandt Mining Company Pty Ltd
location:
Groote Eylandt, NT

Water Technology was commissioned by Groote Eylandt Mining Company (GEMCO) to undertake a river sedimentation analysis for the Angurugu River, Groote Eylandt.

Groote Eylandt is situated on the western side of the Gulf of Carpentaria, approximately 50 km from mainland Australia. The Angurugu River flows between the main GEMCO mining leases, and is fed by a total catchment area of approximately 117 km2. The river discharges into Milner Bay and the tidal influence is known to extend as far up stream as the Haul Road Bridge.

Concerns have been raised that increased sedimentation in the river is occurring as a result of changes associated with the Haul Road Bridge and/or mine operations. In order to understand the sedimentation processes in the river, this assessment focussed on analysing the river planform, flow characteristics and sediment transport potential prior and post construction of the Haul Road Bridge.

Work undertaken included a geomorphic assessment, combined with hydrologic and hydraulic modelling along with sediment transport modelling through the river system.

Key Services Provided:
– Geomorphic Assessment
– Hydrologic and hydraulic modelling,
– Sediment transport modelling

Client:
Malley CMA / Murray Darling Basin Committee
location:
Murray River, VIC

The Living Murray Initiative and associated Environmental Works and Measures Program were established to improve the health of the River Murray system through recovery of water and effective distribution to the environment.

Water Technology has been involved in a number of eco-hydraulic projects through these initiatives to develop and assess water management options for improved environmental watering.

Water Technology undertook hydrodynamic modelling to assess proposed works and measures to significantly enhance the existing watering regime of the wetland systems around Lindsay, Mulcra and the Wallpolla Islands. This involved comparing flood extents based on historical, current and proposed infrastructure management. Prior to the development of environmental watering infrastructure, Water Technology undertook advection-dispersion model, investigated rates of mixing and turn-over times in the upper reaches of the system.

Client:
North Central CMA / Murray Darling Basin Committee
location:
Gunbower Forest, VIC / NSW

As part of Victoria’s Murray Darling Basin Plan Sustainable Diversion Limit Offset Works and Measure’s Program, the North Central Catchment Management Authority co-ordinated investigations to deliver environmental water to the Ramsar listed Gunbower Forest in an efficient and sustainable manner.

The objective of these investigations was to assess hydrological, ecological and structural feasibility of a range of water management options to deliver water to the Gunbower Forest.

Water Technology developed a number of 1D-2D hydraulic models of the system to evaluate the potential water management options and improve knowledge of the floodplain system, and worked closely with the CMA and ecologists to develop concepts of infrastructure and watering requirements for various target sites.

Client:
West Gippsland CMA
location:
Corner Inlet, Vic

The Corner Inlet Environmental Audit was undertaken by the CSIRO (2005) in response to growing concern from natural resource managers and the community about the health of Corner Inlet. One of the key recommendations from the audit was to undertake a catchment audit to identify pollutant sources and develop targeted amelioration strategies. This project responded to this call by developing a comprehensive sediment and nutrient model of the catchments of Corner Inlet. Water Technology and Melbourne University worked closely with the West Gippsland Catchment Management Authority and the Steering Committee for this project to ensure the final outcomes were user friendly and appropriate for the site.
The method pursued was to develop SOURCE (catchment) and receiving waters (estuary) models (MIKE 21), which were calibrated to both existing data and field measurements taken as part of the project. The simulations of these two calibrated models were then integrated within a single software framework so as to produce a Decision Support System (DSS). The DSS allows scenario testing to plan and prioritise future investments in the catchments, and make decisions on what comprises appropriate development with a view to protecting and enhancing the integrity of the Corner Inlet RAMSAR site.

Client:
Coffs Harbour City Council
location:
Coffs Harbour, NSW

In 2012 Water Technology and GeoLink were commissioned by the Coffs Harbour City Council to undertake an Estuary Management Plan and Hydraulic Assessment of the Coffs Creek estuary which runs along the boundary of the main centre of Coffs Harbour.

The estuary is a tranquil oasis on the edge of the city and is utilised by residents and visitors in increasing volumes. An Estuary Management Plan was undertaken to identify and assess management options for the estuary going forwards. In addition, the free passage of flood flows through the estuary was identified as a potential contributor to the severe flooding experienced in the city centre during flood events.

A hydraulic model of the estuary was established and calibrated to measured water levels at the upstream and downstream ends of the estuary. Modelling of a range of management options, including reduction in fringing mangrove density and spread, dredging of the flood tide shoals and tidal entrance channel were assessed.

The runoff from the urban and industrialised sections of the catchments had been studied previously and the information from these works were used to determine potential improvements in the water quality which could be made by strategic upgrade of drainage and water quality systems.

The results of the Hydraulics Assessment were used to help prioritise the management options and to provide the Council and local community of Coffs Harbour with a wealth of information on the drivers of estuary health in their town.

Client:
Maurice Blackburn Lawyers
location:
Western Victoria

Coastal Plume Dispersion – Abalone Viral Gangalioneuritis

Water Technology carried out detailed numerical modelling of the potential release of an abalone aquaculture contaminant into the Southern Ocean off the coast of western Victoria.

As part of the process, Water Technology undertook verification of the numerical model using fluorecene dye tests, released from the facility outflow drains. EPA risk assessments and notification of the local catchment manager and EPA prior to the tests were completed. Overhead shots from a light plane were taken and the images rectified and time stamped.

Numerical modelling of the dispersion involved hydrodynamic and wave modelling of the Southern Ocean, extending from South Australia, south of Tasmania to the Victorian /New South Wales border to the east. The model of the Southern Ocean utilised inputs from global models and was calibrated to predicted and measured tidal stations and recorded wave data. The dispersion of the waterborne abalone virus was verified against the results of the fluoroscene dye test and showed good correlation between the actual and modelled wave setup of water (and contaminant) inshore of the fringing coastal reef.

The model was used to determine the timing and concentration of the dispersion of the abalone virus along the western Victorian coast and through Bass Strait into Port Phillip Bay and Western Port. Scenario optioneering of different contaminant release points and concentrations were used to determine the likelihood of contamination originating at the subject site.

The results of the modelling were used in supporting arguments in the Supreme Court of Victoria and Water Technology was called upon by the court to provide an Expert Witness Statement and provide the presiding judge with additional comment during the hearing.

Coastal Plume Dispersion – Abalone Viral Gangalioneuritis
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