WATERWAY ASSESSMENT & MANAGEMENT
overview

At Water Technology, we pride ourselves on an advanced understanding of the physical processes of waterways and the factors that influence them. We use our understanding to design methodologies that give clients exactly what they need.

We specialise in, and are well recognised for our skills in fluvial geomorphology, ecology, hydraulic modelling, strategic waterway management, design and construction support for waterway rehabilitation, GIS analysis and community consultation.

Our successful delivery of countless integrated and multi-disciplinary waterway management projects throughout Australia is based on these skills and understanding.

We have extensive experience in strategic waterway planning, and a thorough understanding of current best-practice waterway management activities, their limitations, and their implications on stream processes and waterways stability.

Capabilities
  • Integrated Waterway Management
  • Geomorphology
  • Water Quality
  • Ecology
  • Hydraulics
  • Hydrology
  • Fluvial & Estuarine Process Investigations
  • River Stability Assessment & Design
  • Strategic River Health Planning
  • Environmental Flow Assessment
  • Monitoring Program Design & Implementation
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:
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:
Brisbane City Council
location:
Boondall, QLD

Nudgee landfill was formed adjacent to the Boondall Wetlands in 1976. The site was closed in 2002 with remediation completed in 2006. Water Technology staff were members of a team invited to undertake an ecological and water quality study to assess the influence of the Nudgee Landfill on the Boondall wetlands (now a RAMSAR listed site). The study included review of all existing monitoring and modelling data, as well as the design and implementation of targeted soil, water and biological monitoring program over a 2 year period. Automatic water quality and depth sensors (with data loggers) were used extensively. Manual sampling and laboratory analysis was also undertaken.

The Boondall Wetlands water quality monitoring sites were influenced by a number of interacting processes such as rainfall, tidal flushing, time of year and distance from Moreton Bay. Further, the impact of these processes on site water quality varies depending on the site and water quality parameter. Therefore, while the “raw” monitoring data may give a precise measure of water quality at the particular moment of sampling, the incomplete sampling coverage across all sites and times, along with the confounding effects of these various processes, meant that the raw data alone did not provide a complete description of water quality variation over time either at a site or between sites. Advanced statistical analysis was used to model and isolate the various physical, chemical and biological processes occurring within the study area.

The Boondall Wetlands have been subject to numerous historical changes apart from the construction of the landfill. These include, land clearing, drain construction, and waterway dredging. The study was able to isolate and identify the effect of natural and anthropogenic impacts on the wetlands.

Client:
East Gippsland CMA
location:
Snowy River, NSW

This study was prepared for the East Gippsland CMA in June 2011 and involved a detailed hydraulic assessment of the impacts of the Snowy River Rehabilitation Project on the river and floodplain. The study incorporated an iterative hydraulic and geomorphic approach to assessing the implications of the river rehabilitation and also to assess risks associated with potential avulsion sites. A two-dimensional hydraulic model was developed to spatially resolve the effects of changes in vegetation communities along the floodplain and riparian zones on flood levels across the study area. The assessment also considered the effect of in-channel bars under a range of flow conditions, with the results indicating a high level of correlation between increased flood level and channel bar formation. Sensitivity testing of the hydraulic model also revealed that the inclusion of bed scour in the model is a critical assumption, as if the bed does not scour through the system during flood events, water levels and overbank flows are expected to be dramatically raised in a number of reaches, with follow-on effects downstream.

Client:
Goulburn Broken
location:
Yea, Vic

Water Technology, in collaboration with Moroka, was invited to produce a report for the Goulburn Broken Catchment Management Authority on an investigation of the fluvial geomorphology of the Yea and Acheron Rivers. The report is centred on the main stems of the Yea and Acheron Rivers in the settled parts of the valleys and populated areas of the Murrindindi and Steavenson Rivers. The purpose of the investigation and report is to:

• provide an understanding of the underlying physical processes that control the size, shape and location of the river channels; and
• allow these physical processes to be considered as part of developing future river management strategies and as part of day-to-day river management decisions.

This investigation dealt primarily with the physical aspects of the rivers and floodplains. In overview, the investigation confirms that while there will always be particular instances of erosion or flooding that conflict with expectations for the river, most sections of the rivers are quite stable at a management timescale compared to many other Victorian Rivers. Areas where the potential for conflict between geomorphic processes and land use expectations is greatest are in the Yea River from the vicinity of the Murrindindi confluence downstream to Yea, and the Steavenson River downstream of Marysville.

Client:
City of Gold Coast
location:
Gold Coast, QLD

On behalf of City of Gold Coast (CoGC), Water Technology undertook an expert technical assessment (geomorphic condition assessment) and stakeholder consultation, with consideration of stream health condition, primary values and issues within the catchment areas. The outcomes of the assessment were used to prepare an Erosion Management Plan. The Erosion Management Plan aims were to:

  • Identify the erosion processes occurring within each catchment,
  • Outline general management techniques for each erosion process using specific examples from each catchment.

The technical assessment focussed on Wongawallan Creek, Guanaba Creek and Tamborine Creek with reference to present day processes of erosion/deposition, historic geomorphologic change, and likely morphologic trajectories (future changes) both under normal conditions and from flood events. The Plan was developed using various recognised stream management techniques including some aspects of RiverStyles® framework (Brierley & Fryirs, 2005). The management rationale and recommendations provided in the plan are assisting the City of Gold Coast to plan and implement river health projects, mitigate risks and improve the environmental condition of the Wongawallan and Guanaba stream networks.

Through and assessment of the creeks historic and current condition and processes, the likely future trajectory of the creek was assessed. The creeks are frequently controlled by bedrock, with bedrock bars and other exposed bedrock features (channel, bank, and floodplain) observed throughout the catchments. Increased storm frequency (or intensity) will exacerbate existing issues particularly where eroded bank faces are exposed. However, erosion issues within both catchments are acute issues, not widespread.

A vast majority of the stream network in both the Wongawallan and Guanaba Creek catchments were found to be in very good condition, showing high stability, in-channel complexity and resilience. However, active erosion processes are evident within both catchments. A majority of the observed erosion was associated with natural stream processes, exacerbated by land use changes, road crossings and changes in climate.

Client:
BHP Mitsui Coal Pty Ltd (BMC)
location:
SOUTH WATER CREEK, QLD

Water Technology (WT) were commissioned by BHP Mitsui Coal Pty Ltd (BMC) to develop a diversion strategy at the South Walker Creek (SWC) mine to secure mining access to the Mulgrave coal resource area associated with the Kemmis Pit. The Kemmis Pit area represents one of the northern operation areas at the SWC mine and the Mulgrave coal resource is understood to be a high value coal reserve. The Mulgrave coal reserve is transected by Carborough and Walker Creeks. Carborough and Walker Creeks are major tributary systems of the larger Bee Creek catchment, which ultimately flows to the Fitzroy River via the Isaac and Mackenzie Rivers to discharge to the Coral Sea in Rockhampton. The project scope has included the identification of the preferred creek diversion options; Surface water assessments involving hydrological and hydraulic analysis; and fluvial geomorphologic assessments of the waterway systems.

In total, some twenty diversion channel alignment options were identified as part of the study. The alignment options considered a range of scenarios involving channel length, channel grade, diversion take-off and re-connection locations, etc. The diversion options also included short term versus long-term diversion strategies, with the short-term options generally representing the shorter length diversion options. The alignments reflect the nature of the key controls at the site and specifically the local topographical conditions whereby the options have been structured to minimise excavation quantities. The initial diversion options were considered by BMC’s Project Steering Committee and a process of shortlisting of the options was undertaken. Conceptual diversion channel arrangements including channel form and shape and earthwork quantities for five shortlisted options were prepared for consideration by BMC. Two preferred diversion options were ultimately chosen to proceed with more rigorous assessments.

Client:
NT DEPARTMENT OF MINES AND ENERGY
location:
MCARTHUR RIVER, NT

Expert staff from Water Technology’s Brisbane office joined the McArthur River Mine Independent Monitor team, under the management of ERIAS Group. The Independent Monitor (IM) team includes experts in the fields of groundwater, geochemistry, hydrology, hydraulics, ecology, geotechnics, geomorphology, water quality, soil and sediment quality, and mine closure. In addition to ERIAS Group, the team consists of six consultancies from across Australia:

 

  • Water Technology
  • Pell Sullivan Meynick
  • Groundwater Resource Management
  • Environmental Geochemistry International
  • Low Ecological Services
  • Integrated Design Solutions

The IM was first established in 2007 with the aim to assess the environmental performance of the McArthur River Mine and the Department of Mines and Energy. The IM was renewed this year under the management of ERIAS Group. The assessment is based on the review of:

  • Environmental assessments and monitoring activities undertaken by the mine operator (MRM Pty Ltd).
  • Environmental assessments and audits undertaken by the mine regulator, the Department of Mines and Energy (DME).

This is a five-year project for the new team, beginning in 2014 with a site visit to familiarise the team with the Mine, DME and associated staff. The Independent Monitor Audit Report for 2014 (2013-2014 operational period) was released in October 2014 and is available for download at the MRM-Staging Website.

Client:
NORTH EAST CATCHMENT MANAGEMENT AUTHORITY (VICTORIA)
location:
CENTRAL VICTORIA

The Ovens River floodplain is one of the many within the Murray-Darling Basin that has been subject to anthropogenic changes, negatively impacting on the condition of floodplain and wetland environmental assets. The lower Ovens River and its floodplain wetlands are in much better condition than many other rivers in the basin due to the absence of major water storages and extractions from the upper catchment, with less impact on the magnitude, frequency and duration of flooding. However it still has a number of issues to manage; namely vegetation clearance, pest species, the operation of the Murray River and backwatering from Lake Mulwala, and the construction of levees, channel banks and roads, some of which have disconnected wetlands from the river.

The Lower Ovens Connectivity Study was a landmark project which integrated complex floodplain hydraulics, catchment hydrology, advanced spatial analysis, ecological assessments and environmental outcomes. Detailed 1D/2D hydrodynamic models were used to understand the flood behaviour across the floodplain at a range of different magnitude flow events. Extensive condition assessments of the significant ecological assets within the floodplain were also conducted. The study identified and mapped over 380 potential barriers to flow and produced a number of highly valuable datasets which relate areas such as wetland connectivity, frequency of wetland inundation and ecological condition that could serve as a benchmark for floodplain managers across the Murray-Darling Basin. The knowledge gained from the study was incorporated into a geodatabase that linked flood behaviour to connectivity and ecological assets within the floodplain.

The study concluded that much of the lower Ovens floodplain is in excellent condition and that there are few barriers which significantly reduce wetland connectivity, with 90% of the wetlands found to be inundated on average at least every two years. The approach developed in this study could easily be applied to other river systems across the country to improve understanding of the ecological condition and connectivity of floodplains and improve management of key environmental assets. The study has developed a number of tools that will significantly expand the North East CMA’s capacity to engage key stakeholders in identifying options for improving the management of unregulated flows to key environmental assets through the design and management of environmental infrastructure.

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