Your recent editorial (January 7) implied the likely need to recycle water from sewage into our drinking water because of future water shortages.
Previous Actew modelling, however, shows that, after the Cotter Dam extension and the pipeline from the Murrumbidgee to Googong are finished, even with the most prolonged droughts we will have enough water for this city.
Sewage recycling plants have very high initial and ongoing financial costs. Like desalination plants, they also use a lot of energy.
However, most important is the health perspective. These are "very high-risk" proposals and reverse 150 years of good public health policy, where we have strived to keep sewage out of our drinking-water supplies.
Although water recycling from sewage is technically feasible, we need to be very wary. The most extensive scientific review on this issue concluded that adding it to drinking water should be a "last resort".
It should be adopted only if all other measures - other water sources, non-potable reuse and water conservation - have been evaluated and rejected as technically or economically infeasible.
This is obviously not the case for Canberra.
Sewage contains very high concentrations of pathogens and drugs. Viruses (the most difficult pathogens to remove) can occur in concentrations of higher than 1 million viruses a litre and much higher than in even the most polluted rivers. The technical and human performance needed to remove viruses safely will need to be very high.
We would also need to ensure the system works all the time.
Reverse osmosis is the most effective way to remove viruses and drugs from sewage and in theory should remove virtually all viruses and drugs.
Yet, surprisingly, few in-use data are available to verify this belief.
Reverse-osmosis membranes seem to leak. One study found it only removed 92 per cent of antibiotics.
Recent safety reviews showed viruses were still detected post-treatment at three of seven sites on some occasions.
Even large microbes such as giardia were not always removed.
Current reverse-osmosis direct testing (e.g. organic carbon) can only detect relatively large leaks of 1 per cent or more. This is well short of being able to measure the reduction we need for virus removal and reasonable safety.
All this means we should be very wary of any arguments to put recycled water from sewage into our drinking water in Canberra.
Professor Peter Collignon, infectious diseases physician and microbiologist, Canberra clinical school, Australian National University
I have great respect for Jon Stanhope, but his aside about Actew's management of water security projects cannot go unchallenged (Letters, January 9).
It is true that the preliminary estimate of the cost of the new Cotter Dam on which Actew based its initial in-principle support for the project was well wide of the mark, probably because of a lack of recent experience with projects of this kind in Australia.
However, this estimate was never going to be the basis for any decision to proceed with the project.
The subsequent decision to proceed with the project was taken only after a fully defined, rigorously costed and independently reviewed estimate was developed and comprehensive governance, risk management and assurance arrangements established.
Despite the substantial increase in costs, the Cotter project was still judged to be clearly superior to other options including the water recycling project.
The fact the project has experienced delays may be due to the dam site being inundated twice by major flooding in two years. It deserves praise for effective management rather than criticism.
Ted Mathews, Hawker
Not part of the plan
Planning issues were regrettably given scant attention in the recent ACT election. We missed a golden opportunity to debate the urgent need to preserve the heritage and character of Canberra's unique suburban precincts.
The ''Protests over Deakin McMansions'' (January 7, p3) reveal in stark terms what is at stake.
We inherited from previous generations of Canberrans, aided by enlightened governments and forward-looking planners, beautiful garden suburbs where the design and scale of built constructions complemented and enhanced the urban landscapes.
The totally inappropriate structure identified by the Deakin Residents Association in Gawler Crescent is typical of many recent developments in the inner south that ignore the character of the neighbourhood and impinge on neighbours' privacy.
Like many residents of this marvellous part of Canberra, and visitors to it, I find it hard not to weep as I walk past the massively imposing, block-shaped, colourless monstrosities that blight what once were attractive streets and thumb their nose at long-standing garden city values and amenity.
A priority of the Inner South Canberra Community Council is the development of precinct codes which recognise the characteristics and features of individual neighbourhoods valued by the local community and should be taken into account in consideration of development proposals and planning decisions. These codes must be developed in close consultation with the local community and must be enforceable.
Our politicians skated around these issues at the election but residents' groups and concerned citizens generally will ensure they are given the priority they deserve when the assembly reconvenes in a few weeks.
Gary Kent, chairman, Inner South Canberra Community Council
The inner north is also subjected to an onslaught of over-scale buildings that clearly detract from the character of existing residential areas, contradicting the aims of the Territory Plan and the housing code.
Many Canberrans aren't aware how much the rules have changed.
Residents are used to development applications with yellow signs posted on properties to be significantly modified, providing information on how to comment on the proposal.
This system no longer exists. The planning system was significantly modified in 2007-08.
The media reported that homes in new developments would generally not require development approval. The ACT Planning and Land Authority added that a single dwelling not on new residential land would generally require a DA.
A subsequent amendment quietly flew under the radar in 2009, exempting new homes in existing suburbs from a DA. This significantly departed from what the public had understood about the new system.
Another amendment passed last year requiring notification for knockdown-rebuilds; it's unclear if it includes consequential review rights.
We now have a system tilting the balance towards developers against rights of the surrounding community.
Further, a resident who wishes to build a new carport alone would receive more red tape than if they demolished and replaced the entire house, with a new carport, of course.
ACTPLA handles planning specifics, with the Assembly responsible for the overall framework.
The assembly should redress the existing imbalance and reinstate the rights of residents to contribute to their neighbourhood's character.
Mike Hettinger, deputy chairman, North Canberra Community Council
Big breaks needed
I read with interest your editorial on the human role in fire prevention (January 9, p12). But is it not also true that a sufficiently wide physical barrier between regions of combustible material and centres of habitation would protect us from bushfires?
Airborne embers can travel great distances. But surely it is possible to calculate the desirable width of a swath of treeless, regularly cropped grazing land to protect a settlement?
If Australia were to enforce such a precautionary policy nationally by legislation, it would save lives and millions in property damage every year. If we tell bushfires to go to blazes, it should even be relatively safe to have a home among the gum trees.
Barrie Smillie, Duffy
Railing off target
It is sad to see that people such as F. Lamb (Letters, January 9) still live in the past, blaming ''militant trade unions'' for holding ''government and private enterprise to ransom''.
This sort of behaviour usually only took place when the employers - both government and private - stood over their workers with bullying and victimising, not willing to compromise or, in some cases, even negotiate.
The rail system ceased to be viable because governments underfunded it, finding it was a lot cheaper to give the carrying of goods to trucking companies, which in turn exploited truck drivers to keep costs down.
Yet although it is claimed the trucks are now ''safe'', I, like many others, have been scared shitless on occasions trying to pass, or being passed at speed, by enormous trucks when they are literally wandering across the road.
Lamb is right in saying there needs to be co-operation between rail authorities and rail workers (represented by their unions) for a cost-effective, efficient and safe rail system to work.
This will only happen when governments recognise that workers are a crucial part of the system and not some cheap add-on.
Geoff Barker, Flynn
The federal Education Minister, Peter Garrett, has announced that economics and statistics will be included in the primary school curriculum.
He does not say which school of economics will be studied, nor that no two economists ever agree on anything, and that statisticians never agree with economists on what factors should be included in economic modelling, nor the weights to be applied.
Are primary school pupils mature enough to cope with the disharmony between economic schools and between economists and statisticians?
Ed Dobson, Hughes
To the point
'WOMEN' DESERVE BETTER
You report that a ''Mob molests promotional girls at Summernats'' (January 9, p1). The reporter appears to have missed the really big news in the story: that under-age females were used to promote this event. What's that? The females weren't under-age? Then call them what they are: women.
Lisa Jooste, Perth, WA
TREE CHANGE SAVES DAY
I was one who did not realise the extent of tree growth over the last few months, so parts of my suburb ended up without power for some time during the heat of Tuesday. Due to the courtesy and efficiency of the crew from ActewAGL, the power was soon restored and the offending tree pruned. Many thanks, guys, for a job well done.
Chris Davey, Holt
AUSSIE, AUSSIE, AUSSIE
Given that the tennis competitions being broadcast on television are for individual players playing for themselves, why is it that the Australian flag is being displayed alongside Australian players' names, yet not the flags of players from other countries?
P. J. Carthy, McKellar
MY WAY OR HIGHWAY
Robert Willson's latest missive to atheists (Letters, January 10) is virtually a declaration of war against anyone who doesn't share his beliefs. His intolerance is palpable. What part of ''Love thy neighbour'' does he not understand?
Diana Shogren, Weston
F. Lamb (Letters, January 9) warns us of the perils of industrial disputes when transporting freight by railways instead of trucks on roads. Perhaps Lamb has forgotten Ted ''Greendog'' Stevens's blockade of the Hume Highway over Razorback?
Paul Rogers, Aranda
FIGHT FIRE WITH FIRE
Is there nothing the Opposition Leader - that Bible-bashing, relentlessly negative misogynist, Tony Abbott - won't do to get attention? Not satisfied with stunts like teaching Aboriginal children, helping his colleagues manage IVF treatment and involving himself regularly in charity work, he's now out fighting bushfires. What a disgrace.
H. Ronald, Jerrabomberra, NSW
CROWLEY SAYS THANK YOU
Jonathan Crowley and his family would like to thank all of our friends and so many of the general community for their support for Jonathan's continuing struggle for justice. It has been extremely helpful for Jonathan and his family after hearing the devastating decision of the Supreme Court Appeals Court.
Keith Crowley, Chapman