STORMWATER MANAGEMENT & IMPROVEMENT
overview

Water Technology has a diverse history of stormwater quantity and quality assessments throughout urban areas. Having significant and well-respected skills in both flood modelling and water quality assessments, Water Technology provide truly integrated stormwater solutions, which meet the required objectives in a cost effective, aesthetic and environmentally sensitive manner.

There is an increasing focus on both integrated water management and Whole of Water Cycle Management (WoWCM) to meet the challenges of the demanding Australian environment of droughts and flooding rains. Urbanisation and a focus on liability provide opportunities to bring together the management of floodwater with innovative methods of Stormwater quality improvement and water supply.

Our broad skill base in urban flood modelling, WSUD design, waterway management, and water quality monitoring combined with our experience working with a range of Councils, water authorities and private developers enable Water Technology to provide these services in a cohesive product, which meets the needs of our clients.

Capabilities
  • Stormwater Management Plans
  • Whole of Water Cycle Management
  • Integrated Water Management Strategies
  • Urban flood modelling, mitigation and management plans
  • Water Sensitive Urban Design
  • Conceptual and Functional Design of drainage assets and wetlands
  • Emergency management advice
  • Water quality monitoring and reporting
  • Drainage Strategies
  • Stormwater Harvesting
  • Water Balance Modelling
Creating a Stormwater Management Plan for Curtin University
Client:
Curtin University
location:
Victoria Park, Bentley, Western Australia

Curtin University is Western Australia’s largest university. The main campus in Victoria Park, Bentley, supports a large student and staff population with a wide range of facilities and open space (approximately 117 hectares in size), including water bodies. Understanding the existing flood risk and assessing the impacts of proposed future development on the campus is important for planning and development decisions.

Stormwater Management Plan

Water Technology was commissioned by Curtin University to undertake a stormwater management plan of the entire Curtin University site in Victoria Park. Previous work had only considered small sections of the site’s catchment in isolation. The purpose of this project was to analyse the impacts of stormwater flooding for the entire site under existing conditions so that problem areas could be identified, and to assess the impacts of any future development. A detailed TUFLOW rain-on-grid hydraulic model was developed using LiDAR, feature survey and design drawings along with pit and pipe data from a collection of sources.

Complex hydraulics that included ephemeral lakes and numerous infiltration basins

The hydraulics of the site are significantly complex, including ephemeral lakes and numerous infiltration basins. As such, there was a need to work closely with the client to gain an in-depth understanding of the various features in the process of developing a model that was appropriate and reflective of the site.

This stormwater management plan study produced a significantly detailed TUFLOW hydraulic model, which is a valuable tool in identifying the flood risk on the Curtin University site for both existing conditions and future developed conditions. The work included the use of the model to simulate flood behaviour through the proposed ‘living stream’ network. The results from the modelling were used to assess potential impacts on the hydrological regime of the ‘living stream; system, and provided a range of recommended management measures to manage or mitigate any impacts.

Key Services Provided:

  • Site inspections
  • Hydrological modelling
  • Hydraulic modelling using TUFLOW with rain-on-grid
  • Detailed stormwater drainage network analysis
  • Flood impact and risk assessment
  • Scenario analysis and recommendations
  • Stormwater Management Plan
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:
Driscoll Engineering & Hindmarsh Shire Council
location:
Dimboola, VIC

Water Technology in conjunction with Driscoll Engineering, undertook a drainage investigation for Hindmarsh Shire Council following flash flooding in the Dimboola Township in January 2011. A 1D/2D hydraulic TUFLOW model was developed for the Dimboola study area which is approximately 330 m north-west of Melbourne. A hydrological model using RORB was developed for the study area in conjunction with the Rain-on-Grid inputs for the hydraulic TUFLOW model. Several stormwater mitigation options were investigated for the Dimboola Study area, with the flood and cost benefits for each scenario investigated. Ultimately a desirable drainage solution which significantly reduced the flooding risk and also created an important community asset was developed through the study.

Client:
Global Advanced Metals and Atlas Iron
location:
Port Hedland, WA

Water Technology prepared an integrated stormwater management assessment, including conceptual and detailed design of the stormwater management system for the Wodgina Mine Site (Global Advanced Metals and Atlas Iron) south of Port Hedland, WA.

The work undertaken included on-site assessment of flooding and stormwater constraints, flood modelling and identification of the impacts of flooding on proposed and existing mine developments. This information was then used to develop a site wide water management plan with design options including culvert locations and sizing, sediment pond location and sizing, surface grading and stormwater transfer channel location and sizing.

Client:
Western Downs Regional Council
location:
Western Downs, QLD

Water Technology have stormwater and riverine flood studies for six towns in the Western Downs Regional Council (WDRC) area using MikeFLOOD to assist with the revision of their planning scheme following recent council amalgamations. Water Technology has also provided expert advice to WDRC with respect to inclusion of the modelling results in the scheme. Stormwater and riverine flooding studies have been undertaken for Chinchilla, Miles, Wandoan, Tara and Jandowae. In addition, for Dalby we have undertaken a stormwater study and assessing the effect of recent development on flooding through modification of the existing riverine flood model (developed by others). The riverine flood study identified areas at risk of inundation and their impact on current and future development. The stormwater analysis defined and mapped stormwater corridors, and defined trunk drainage infrastructure needed for development.

Interesting challenges that were faced during the project include: determining representative observed rainfall and runoff data, regionalisation of flood frequency analyses, regionalisation of model parameters, application of areal reduction factors to rainfall estimates on large catchments, stormwater flow path identification in (very) flat terrain and identification and documentation of structures (e.g. illegal bunds).

Client:
City of Casey
location:
Cranbourne, Vic

The City of Casey is committed to deliver innovative, sustainable water management practices within its municipality and to use the ‘Complex’ site as a showcase for ground breaking examples of design and sustainability. Currently, the Casey RACE re-uses onsite rainwater collected from the CILC’s existing roof and treated pool backwash water to substitute potable water consumption for pool “top ups”, toilet flushing, showering and landscape irrigation. From the 10 million litres normally used for backwash, approximately 75% are now recycled.

In this constant effort for water conservation and sustainability design, the City of Casey wishes to identify opportunities for a green roof and additional IWM options for the site. This study aimed to deliver a complete investigation of IWM options for the precinct including the completion of a business case illustrating the costs and benefits to each stakeholder, a shortlisting of ranked options and recommendations for suitable IWM option(s) incorporated as part of the future redevelopment plan.

Building on the existing works, the aim of the project was the delivery of a clear and comprehensive IWM option study. Our team of experts worked collaboratively on the Green Roof and Green Wall options, the identified IWM options and modelled their performance in MUSIC, the financial analysis and the engagement and presentation to a stakeholder group. Water Technology has formed a highly capable study team to deliver this project. Our project partners BENT Architecture and Essential Economics are recognised experts in their fields with strong track-records in green infrastructure and economic analysis respectively

Client:
Baw Baw Shire Council
location:
Warragul, VIC

Water Technology was engaged by Baw Baw Shire Council to design and model a proposed combined Retarding Basin (RB) and Wetland (WL) located north of Stoddarts Road, Warragul. This proposed RB/WL forms part of Council’s overall Development Contributions Plan for the Shire. The project included the design of a retardation system consisting of two storages connected in series, three sediment ponds treating a proposed development and the greater catchments flows, one wetland as well as the realignment of an unnamed waterway. A hydrological RORB model was built for the Stoddarts Road catchment in order to design the size and characteristics of the retarding basin. MUSIC was used to size the stormwater WSUD treatment assets before preparing the design drawing for submission to Council. Figure 4 4 shows the Stoddarts Road Wetland detailed design drawing. An Initial ANCOLD assessment was undertaken for the retarding basin infrastructure as part of the design.

Client:
Wyndham City Council
location:
Wyndham, VIC

Water Technology is working with Wyndham City Council and Melbourne Water to develop a stormwater treatment road map for the municipality. This study intends to enhance the work undertaken to date, and provide an action plan for future works that are needed to provide best practice treatment.
The two key project objectives are as follows:
• Update the Stormwater Management Plan to represent the current state of implementation and changes to industry standards.
• Provide easy to interpret action plans to assist in developing works plans and setting budgets.
We are providing a document, which clearly states what is required by Council to meet the stormwater objectives and a roadmap for implementation. This will be presented in the form of project-oriented outcomes, which can be easily translated into achievable projects over a range of timescales, with budgets and outcomes defined.
The road map document identifies and prioritises the works needing to be completed in order to provide cost effective and thoroughly scoped projects. Key topics include:
• Water Sensitive Urban Design – Identifying where there are gaps in the municipality and where effective and appropriate features will add value.
• Recording System and Maintenance Program – Ensure all assets are accounted for in the maintenance system and appropriate budgets are allowed to maintain the features. This will involve consultation with the maintenance staff to ensure we fit in with their current schedules, and discuss if any changes are needed.
• Integrated Water Cycle Management – Where realistic opportunities exist to use water in a more efficient way. This will include where there is opportunity to provide flood protection, water quality and water harvesting in multi-objective systems.
• Planning Schemes – Determine if any changes to the planning scheme or policies are required in order to achieve the objectives in the strategy.
• Asset Management Programs – Work with Council to identify how the asset management system can incorporate the stormwater features and enable short and long-term budgets to be allocated.

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:
MAB Corporation
location:
Epping, VIC

A Stormwater Management Plan was developed by Water Technology for a new major industrial subdivision in Epping, north of Melbourne. The SWMP involved the reworking of Melbourne Water’s Edgars Creek Development Services Scheme to achieve a consolidation of drainage infrastructure whilst also achieving a development layout for the subdivision. Through collaboration with Verve Projects, GPR Consulting and CDA Design Group, the project resulted in the functional and detailed design of approximately 850 m of new constructed waterway, a major regional retarding basin incorporating a 2 hectare wetland, plus the sizing of three major waterway crossings.

Stage 1 on the waterway design works commenced in 2013 with commencement of further construction works to occur in the coming years.

Client:
location:

Water Technology was commissioned by the City of Kingston to complete Flood Mapping across numerous catchments within the Municipality. Water Technology worked in close collaboration with council and combined the invaluable local knowledge of Council officers and the community, with state-of-the-art and innovative hydraulic modelling techniques. This provided robust and defendable deliverables to inform the decision making process within Council.

The study allowed for an improved understanding of the existing flood risk within the municipality. Council officers were educated in the mechanisms of flooding within their municipality in order to deliver a customer education solution along with traditional engineering mitigation solutions. Education is seen as one of the most powerful methods of engaging the community and minimising flood risk. By utilising the knowledge of council officers, model development was streamlined and outputs were more credible and readily accepted by both council and the community.

Client:
North Central CMA and City of Greater Bendigo
location:
Bendigo, VIC

Water Technology was commissioned by North Central CMA and City of Greater Bendigo to complete the Bendigo Urban Flood Modelling Project. The area flood-modelled was in excess of 23,300 Ha making it one of the largest and most comprehensive flood studies ever completed within Australia. Innovative modelling, data management and result display methodologies were required to be developed. Engaging with a large range of stakeholders, the study produced practical outputs that were tailored to Council and CMA needs. A critical aspect of the delivery was training council and CMA staff in the use of models and interpretation of outputs.

This was a landmark study for flood mapping of large urban areas. Utilising both traditional (hydrograph input) methods and more recent methods such as direct rainfall on grid, the study was the first of its kind on this scale, setting the benchmark for future work of this nature. Council and CMA now have detailed flood risk data across the entire catchment to inform decision making processes. This includes the most appropriate future capital expenditure and importantly, provides the opportunity for a safer and more liveable city through reduced flood risk and better integration of water with the urban landscape.

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