Wellington Dam
Wellington Dam is an existing irrigation dam on the Collie River located near the town of Collie in the South West of the State. Harvey Water manages the irrigation district that lies downstream. The dam is a popular recreational, fishing and boating destination.
Currently, the Collie and Muja power stations use Collie Coal Basin groundwater.
Water resource issues in this area are complex due to the connectivity of the surface and groundwater resources, multiple users and the high salinity of water in Wellington Dam. In addition, the dam yields are also declining due to reduced rainfalls in recent years. Projections are for continuing declining rainfalls due to drying climate, although there may be some very wet years at times.
The State Government considered further development of the Wellington Dam and Collie groundwater water resources in 2007. The report ‘Water Source Options in the Collie-Wellington Basin’ was released in May 2007.
The report noted that Wellington Dam and Collie Basin groundwater are potential sources for public water supply. The study examined a range of options, but recommended more detailed work before decisions could be made. The Department of Water is responsible for further investigations of the recommendations made in the report.
The Water Corporation has examined three options to develop these water resources for public water supply:
- short–term groundwater - there is a short term surplus of groundwater currently set aside for mine dewatering. This water is of relatively high quality and could be accessed as a drinking water supply. The water could be pumped into Stirling Dam and then on to the IWSS water grid.
- long-term groundwater - if water could be supplied to the power stations from Wellington Dam instead of groundwater, the groundwater may become available for long term public water supply. A 10 gigalitre a year scheme could be developed using Stirling Dam to store the water. This would require substantial upgrades to the Stirling Dam infrastructure to connect it to the IWSS water grid; and
- development of Wellington Dam for public water supply - Wellington Dam could provide a 30 gigalitre a year source for public drinking water supply. This may require a desalination plant downstream of Wellington Dam and a new trunk main to connect to the IWSS (unless the water was retained for regional use). This option is very complex and would require irrigators to trade their current allocation to the public water supply. There are also significant catchment management issues that would require resolution, as the Dam is a popular recreational area.