Information Sheet- Gingin-Jurien Groundwater
Background
The Water Corporation has undertaken conceptual planning for the potential development of new groundwater schemes drawing water from the Perth North Basin from Gingin to Jurien.
The proposed Gingin - Jurien Groundwater System intends to extract groundwater from the superficial and confined aquifers in the area north of Moore River towards Badgingarra. The groundwater area is generally between the coast and the Brand Highway. It covers a large area extending north-south for about 80 kilometres and east-west for 30-40 kilometres.
Planning has identified three borefields; Mimegarra, Wedge Island and Badgingarra. The Mimigarra and Wedge Island bores, located closer to the ocean, would extract water from sand and limestone aquifers. The Badgingarra bores would extract water from the Yarragadee aquifer. They could be developed as 3 separate schemes, but there are advantages in mixing the raw water together, treating it and then pumping it via one system into the water grid.
The Mimegarra and Wedge Island groundwaters are expected to have high hardness and low salinity. When mixed with the Badgingarra groundwater, the overall hardness should be within limits for drinking water. All groundwaters are expected to require treatment for iron and manganese removal.
Collectively, the borefields could supply up to 75 gigalitres per annum. Staged development of the scheme would be possible.
Current Situation
Conceptual water source planning has been undertaken. This scheme has the potential to provide a significant additional resource for Perth’s water supply and is a potential groundwater source for consideration in future source development planning.
However, significant technical, social and environmental issues require further investigation. Obtaining environmental approvals for infrastructure would need to consider the A-Class nature reserve and National Park in the area. There is also expected to be competition for any new water allocations, from irrigated agricultural users in the area.
Source protection is an important issue and would need to be resolved with the Department of Water.
The Future
- Mimegarra Borefield – Proposed to have 19 bores with a total yield of about 12 Gl per year.
- Wedge Island Borefield – Proposed to have 44 bores with a total yield of about 23 Gl per year.
- Badgingarra Borefield – Proposed to have 14 bores with a total yield of about 40 Gl per year.
The three borefields would pump to a treatment plant east of Lancelin. From there the treated water would be pumped to Mt Yokine Service Reservoir for supply into the water grid.
The scheme development could be staged to better match the quantity of water delivered to the rate of demand growth. However, the initial stage of development is likely to require proportionally more capital expenditure as many of the common scheme components, particularly related to water transfer infrastructure would be needed for the first stage.
This groundwater scheme is well placed to serve the future demands in the local area. Perth by 2060 will be extending up into these areas, in particular, Ledge Point and Lancelin and south to Yanchep.
Sustainability Considerations – addressed in planning
Economic | Social and Cultural | Environmental |
| Standard groundwater scheme, similar to many others the Corporation owns. | Can supply local areas with water. | Potential impacts on wetlands in and around the Moore River and Nambung and Badgingarra National Parks. Possible impacts of water levels in Karst Limestone. |
| The groundwater system is far from the main demand areas – increasing the overall cost. | Aesthetic impacts of the water treatment plant and pump stations at Moore River and Wanneroo. | Potential impact on Nilgen and Wannagarren nature reserves. |
| High energy demand if required to supply water to Perth. | Competition for water allocation with local agricultural users. | Potential impacts of pipe construction within the Badgingarra National Park. |
Potential source yield
The potential yield is 75 gigalitres per year. This is enough to supply more than 300,000 new homes.
Potential cost
The cost today of the Gingin – Jurien Groundwater scheme is estimated to be in the order of $1-$2 per kilolitre. The costs have two main components:
- the borefields and treatment plant and
- connecting the plant to the water grid and transferring water to customers.
Key
Potential source yield (in 50 year planning horizon)
Potential cost (2007 $)