Alternatively, close it down and move it to boganville.

Ian Jannaway, Monash

Gary J. Wilson writes that "multinational corporations have decided to frack Australia" and will exert "massive financial pressure ... on our governments to frack the entire land mass" (Letters, January 10, p15).

I think that I, as a geologist, can help ease Gary's concerns. Only certain types of rocks – those both known or reasonably deduced to have high hydrocarbon contents and to have certain (relatively brittle) properties – are potential targets for fracking.

These sorts of rocks are found in a relatively small proportion of the Australian land mass, including south-central, central, and central-eastern Queensland, and the Hunter Valley region of NSW.

Of course fracking can be ecologically harmful, as was argued in recent cases against fracking in the Liverpool Plains and the Pilliga Scrub. This is when proper, long-term cost-benefit analyses must be carried out.

In any event, I think that Gary need have no concerns that "the entire land mass" of Australia could be fracked.

Douglas Mackenzie, Deakin

Ian Douglas thinks speeding up traffic could save billions on road construction (Canberra Times, January 7, p16). If only the speeding up of slow drivers encountering an overtaking lane could be produced by trickery, such as holograms, he says.

But road capacity doesn't increase as traffic speeds, or drop as traffic slows. The number of vehicles per minute, or per hour, is much the same at every speed: the necessary gap between vehicles is constant (between two and three seconds per vehicle, with a loss of carrying capacity due to accidents if the gap is not maintained).

Speeding moves no more vehicles; conservative driving moves no fewer.

There are no solutions to additional road traffic, if it exceeds carrying capacity, other than to increase the number of lanes that traffic can use or to decrease the volume of traffic.

But new roads and new road lanes are not subject to cost-benefit analysis by letter writers in these, or other, pages.

Christopher Hood, Queanbeyan

As predictable (and as annoying) as the appearance of hot cross buns in supermarkets on January 2 each year, we also have the start of the annual debate on Australia Day with ABC Radio this morning discussing "alternative, less divisive" days. Perhaps just once, the majority could be allowed to celebrate our national day without the usual orgy of self-flagellation and guilt-tripping by some who aim to ignore or rewrite history.

Quite simply, there is no date in the history of this continent that so totally defines the nation we live in as that date that marks the commencement of British settlement. That single event impacts every single aspect of our daily lives – our language, our laws, our society. No other day has had that impact and Australia is the nation it is today because of it. To suggest otherwise is to deny reality. If some aspects of our society need improving, then so be it – let's work on them. But at the same time, let's not diminish all the successes and the greatness of this country by pretending that changing Australia Day will make any difference at all to any perceived shortcomings.

Here's cheers to Australia Day!

Kym MacMillan, O'Malley

The slug to chickpea and lentil farmers is likely to be a matter of revenue rather than protectionism ("New Indian 30% tariff to hit farmers", December 28). Despite the tax, last financial year's exports of chickpeas to India, $1.1 billion, "are projected to drop 27 per cent" this year.

That is, the volume or weight of the export is expected to increase. The real indicator will be in 2018-19. The expected increase in exports for the current year reflects forward planning, not profit. Next year we shall see if it is still worthwhile producing for the Indian market, which took 57 per cent of our production last year.

It is difficult for Australia to take such an approach to revenue. A country needs to be the major or sole market of the supplier for such a manoeuvre, or bluff, to work. Where a nation's main market for most of its produce is a single client, that nation becomes a vassalstate.

Gary J. Wilson, Macgregor

On Thursday morning walkers and rowers were upset to find a kangaroo in distress in the middle of Lake Burley Griffin in front of the NGA.

I was further disturbed to find out that this is a common problem, one that no local authority takes responsibility for. Apparently, the kangaroos will fall or accidentally jump into the lake unable to find a way out due to the vertical wall surrounding the lake.

The heartbreaking sight of the kangaroo up to its neck in water, dazed and unable to move with fright and exhaustion will stay with me always.

I was told by two different people that this is a regular occurrence and that no authority will respond. One fellow in a dinghy (helping the rowers) has tried himself a number of times to help different kangaroos. However, on his own it's usually impossible.

I believe that as National Capital Authority infrastructure is responsible for this horrifying situation the NCA needs to take responsibility. The NCA must immediately make available a way of to help rescue these unfortunate kangaroos. Some may argue that the kangaroo is a pest in the city, but this situation is cruel and intolerable. Shame on Canberra for doing nothing.

Theresa Gordon, Kingston

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