Site selection process (archive)
Following an extensive site selection and analysis process, and stakeholder and community engagement, Western Power, in agreement with the Water Corporation, has identified Site 2 as the preferred location for the replacement substation. Site 2 is located below the weir on Old Mundaring Weir Road. The proposed site is on Water Corporation controlled land, a short distance from the existing substation.
Site 2 provides clear benefits in terms of cost, environmental impacts and has no direct impact on residents, as shown in the following comparisons of the final four sites identified for further consideration.
- Site 2 - Has the least environmental impact (less than 1 hectare of clearing and least likely impact on Carnaby Cockatoo habitat), is the least cost option and has the least impact on local residents;
- Site 3 - Would have extensive environmental impacts compared to Site 2 (3 hectares of clearing with impacts on Fred Jakoby Park and Carnaby Cockatoo habitat), and is over 60% more expensive than Site 2, due mainly to its topography and ground conditions;
- Site 5C - Would have extensive environmental impacts compared to Site 2 (4 hectares of clearing in State Forest with resultant impact on Carnaby Cockatoo habitat), has a high security risk given the secluded location and is at least 30% more expensive than Site 2. There is also potential for the transmission line interconnections at Mundaring Weir Road to create a visual impact on local residents. In addition, from an engineering point of view, Site 5C appears to be the most expensive. This is due to the existence of a very hard layer of sub-surface Laterite, which will make earthwork operations more costly. Geotechnical investigations indicated that Site 5C was the only location where Laterite was present. This site represents the highest risk from an environmental approval perspective at both State and Federal levels. The Department of Environment and Conservation (DEC) has indicated that it would oppose this site, and given the DEC would provide input to the project’s referral to the Environmental Protection Authority (EPA), it is likely the EPA would formally assess the proposal and may oppose the development altogether given there are other viable options with significantly lower environmental impacts. There is also a risk of rejection (or value write-down) by the economic regulator because of the significantly higher cost (+30%) of this site; and
- Site 8 - Would have environmental and tourism impacts (2 hectares of clearing and would require the realignment of the Kep Track and Munda Biddi Trail), has European heritage impacts, residents close by and is some 10% more expensive than Site 2. In addition, following preliminary design work it was determined by Water Corporation that the proposed location of the substation would impact on the functionality of a Water Corporation operational asset (Bundaleer Tank), requiring the relocation of the tank at considerable additional cost and with delays to delivery of the project beyond the required in-service date. This was not acceptable to the Water Corporation.
Alongside the analysis undertaken on the site options, extensive stakeholder and community engagement took place to identify constraints, opportunities and preferences that have been fed into the site selection decision making process. This included regular updates, site visits and extraordinary meetings with the Water Corporation’s Community Reference Group (CRG) and multiple briefings with Water Corporation, Shires of Mundaring and Kalamunda, Department of Water, DEC, Heritage Council of WA, Tourism Western Australia and National Trust WA. Briefings were also provided to State and Federal Members of Parliament.
The next step in the process is to finalise the substation design and seek the necessary approvals to construct. It is expected that construction will begin towards the end of 2011 with a completion date of December 2012. The existing and new substations will operate in tandem for about a year. The existing substation will then be removed and the site rehabilitated.
