WA redistributed (slight return)

The Western Australian electoral redistribution commissioners have unveiled the final boundaries for the state’s momentous one-vote one-value redistribution. A number of amendments have been made to the proposals unveiled in June, most of them in the East Metropolitan region:

• Central Kelmscott, which was originally to have been in Darling Range, will now be in Armadale so that boundaries conform with the Wungong Urban Water area. In exchange, the southern part of Armadale as originally proposed (Wungong and Mount Richon) will go to Darling Range.

• The exclusion of the part of Gosnells containing the town centre and council offices from the electorate of that name – described in the Boundaries Commission report as an “oversight” – has been corrected by having the northern boundary follow the Canning River (barring a small strip east of Albany Highway). This has involved a gain of territory from Kalamunda and a loss to Forrestfield.

• To allow greater conformity with suburban boundaries, Kalamunda takes part of Gooseberry Hill from Forrestfield and Darlington from Midland, while losing Glen Forrest to Swan Hills. Midland is compensated by taking Guildford from Belmont.

• The boundary between Swan Hills and Darling Range has been redrawn so that Mundaring and Mahogany Creek are in Swan Hills, while Mount Helena, Chidlow and The Lakes are in Darling Range.

Elsewhere:

• In Mining and Pastoral, the electorate name of Kalgoorlie will now be retained, after it was originally proposed it be changed to Goldfields. The boundaries have been adjusted to include the huge but mostly empty eastern part of the Shire of Ngaanyatjarraku, originally to have been in Pilbara. UPDATE: It seems I speak too soon – the ABC points out that the seat becomes “more marginal after taking in the small community of Warburton”. Its enrolment increases from 12,756 to 13,656, and the 900 newcomers should cut the margin to a little over 5 per cent. So the big loser from the final determination is Matt Birney.

• In South Metropolitan, tiny adjustments have been made to Riverton’s boundaries with Jandakot to the south-west and Cannington to the north-east, so that Leeming is in Jandakot and all of Riverton is in Riverton. Three adjustments have been made to the safe Labor electorates in the southern coastal corridor: there has been a minuscule swap between Fremantle and Cockburn, and a bigger but no more consequential addition of East Rockingham to Rockingham from Kwinana.

• In the South West region, the proposed district of Murray will instead be called Murray-Wellington, reviving a name that existed prior to the 2005 election. There has also been an adjustment to its boundary with Mandurah, which absorbs 671 voters at South Yunderup.

I’ll leave the calculations to Antony Green (whose margin calculations for the boundaries as originally proposed can be seen here), but my rough reckoning is that the adjustments are slightly favourable for Labor, who had done pretty well to begin with. They get a handy boost in Forrestfield (original notional margin 3.8 per cent) and Darling Range (0.5 per cent), and are harmed just slightly in Kalamunda (0.2 per cent) and Swan Hills (3.9 per cent). The Murray to Mandurah transfer is perhaps of slight benefit of the Liberals, cutting into Labor’s initial 8.2 per cent margin in Mandurah. The Liberal margin of 6.3 per cent in Murray was probably understated due to the strong personal vote of Labor’s Mick Murray (member for Collie-Wellington) in much of the affected area, and it is unlikely the seat will be keenly contested at the next election.

I also had occasion some time ago to calculate the results that the new upper house arrangements would have produced with the 2005 election figures. Most interestingly, the lower quota in South Metropolitan (which will go from five seats to six) would have delivered a seat to narrowly unsuccessful preference harvesters the Fremantle Hospital Support Group. Results from the 2005 election shown in brackets.