Water Case Studies
Recycled Water at Western Port
A water-recycling project is being progressed at the Company’s Western Port facility in Victoria, Australia. The project, involving a partnership between BlueScope Steel, South East Water and the Victorian Government, includes a significant upgrade to South East Water’s Somers Treatment Plant. It is expected to significantly cut fresh water consumption at the Western Port site and enable a significant proportion of the wastewater discharged from the site to be treated for reuse.
Sydney Water Award
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The Port Kembla Steelworks won an award for largest volume reduction at the annual Sydney Water Business Customer Awards during the year. The award was based on water savings achieved from plant improvements as part of the No. 5 Blast Furnace Reline project. The Steelworks has saved more than one million litres of water a day by actively promoting water efficiency in new capital projects and improving existing manufacturing processes. |
New Fish Pass at the Taharoa Ironsand Mine
Situation
In the early 1970s, a dam was installed across the Wainui Stream at the Taharoa Ironsand Mine in order to provide water to the dredge, the concentration plant and for slurry ironsand loading to ships.
In order to provide breeding fish with continued access to the sea, a fish pass was installed to provide for migration of juvenile fish into the Taharoa Lakes.
Despite a number of significant modifications over the years, the original fish pass did not allow for effective migration of the fish. In 2007, New Zealand Steel Mining launched a project to install a new fish pass.
Optimum Design for Water Flow
The design phase, undertaken over a 2½ year period, involved international experts on fish passage design and field practitioners. The investigation phase included scaled modelling of key parts of the fish pass to ensure water flows and flow rates were optimum. A key component in progressing the design and commencing construction was consultation with the Department of Conservation, Taharoa Lake Trustee Committee, the landowners and the local community.
 Upstream exit to Wainui Stream water supply reservoir. |
 Baffles installed to reduce water flow and create resting spots |
Result
In mid 2010 the new fishpass was constructed. This involved:
- In-stream works to construct a weir so fish would be passively directed into the fish pass;
- Installation of a larger culvert under the site access road to provide more light and air;
- Extension of the existing concreted sections with baffles either side of the dam, through to an exit pool into the water reservoir
- Enhancement of the lower stream area to improve whitebait spawning. This involved planting in the riparian zone, as well as ongoing animal pest and weed control.
The commissioning phase included development of a monitoring protocol to determine the effectiveness of the fish pass.
Peak fish migration occurs from September to February and monitoring will consist of two phases:
- Placing a trap at the pass outlet once a week for up to 24 hours.
- Five-day intensive fish surveys in October and February, including night time spotlighting, sampling in the stream and the pass.
Fish caught will be counted and identified. A wider catchment survey is also to be conducted over two years involving fisheries survey in three tributaries and the three Taharoa Lakes. NZ Steel Mining is involving the local community in the monitoring and planting programs.
