Thursday 25 November 2010
Hansard of the Legislative Council
SPECIAL INTEREST MATTERS
TAMAR ESTUARY SILTATION
Mr FINCH (Rosevears) - Madam President, if we did not know
it already, the upper estuary of the Tamar River is in a mess,
according to the latest report from Natural Resource Management
North - NRM North. The report breaks down the Tamar estuary
into five zones. Starting near the mouth, zone 5 is rated
A minus; a little further upstream, zone 4 is B plus; zone
3 is rated B; zone 2 at B minus; and at Launceston zone 1
is rated at D. So we have a steady decline as we go upriver.
A D rating, according to NRM North, means a highly degraded
ecosystem, poor water quality, with high levels of turbidity.
That is no surprise. The problem has been going on for generations.
Last year this House set up a select committee to investigate
the management of the Tamar and Esk rivers. The evidence that
the Tamar estuary's problems and its catchment were linked
was overwhelming. The committee recommended the establishment
of a single statutory authority to oversee the management
of the Tamar and Esk rivers and their tributaries. Nothing
has happened. However, there is strong evidence from elsewhere
that single catchment authorities are the only way to remedy
problems like the Tamar's.
Our committee, you might recall, looked at catchments in Victoria,
at Bairnsdale and Corangamite, and Victoria, I might point
out, has 11 catchment authorities working very successfully.
But our most interesting visit was to Moreton Bay in Brisbane.
Moreton Bay has a similar silt problem to the Tamar and I
would like to detail what is being done there.
Members of this House might recall Brisbane Lord Mayor Campbell
Newman's connection back to Launceston - father Kevin and
mother Jocelyn Newman. The biggest threat to Moreton Bay used
to be sewage and other pollutants, but now it is sediment
brought down from small catchments way upstream of the Brisbane
The latest report card on Moreton Bay gave it a rating of
C. That is marginally better than last year's D, so you can
see the similarity of the problem. Brisbane's Lord Mayor has
decided to finance the restoration of upstream catchments
where the silt originates.
Over a 10-year period this could cost as much as $500 million
- that is, $35 million to $50 million a year will be spent.
Lord Mayor Newman says the big challenge is way upstream from
Brisbane and not generally in the Brisbane local government
area. The chairman of a study panel on the catchment problem,
Paul Greenfield, says upstream areas of the catchment are
the problem, with half of all streams degraded. He says that
if you want to improve the estuary, you have to tackle that
To handle heavy rain, catchment erosion has to be managed,
creek channels stabilised, riverbanks improved and investments
made in agricultural practices and water sensitive urban design.
Madam President, by applying a whole-of-catchment approach,
practically each sample of silt in Moreton Bay can be scientifically
traced back to its source. Radiation sampling and computer
modelling are some of the tools being used, and all this information
could help a management authority target the greatest problem
areas and so concentrate the rehabilitation money where it
is most needed.
So far the scientists have found that, typically, 80 per cent
of the sediment load derives from less than 10 per cent of
the catchment area. This information is helpful in targeting
We can learn a lot from what they are doing in Moreton Bay.
I know the upper Tamar's problem is not just about new silt,
it is also about the silt already in the basin being washed
back by tidal movement. The silt that is already there may
well be the major part of the problem but you also have to
tackle eroded sources upstream, way back into the catchment.
That requires a coordinated approach like Brisbane's. Evidence
to last year's committee hearings acknowledged that NRM North
and other groups were doing a fantastic job, but all this
work needs coordinating, as in south-east Queensland and other
mainland estuaries with problems.
That was the recommendation of our committee which featured
the member for Windermere and the member for Launceston. A
statutory management authority was the recommendation to manage
the whole of the Tamar catchment. But, like a lot of good
advice in Tasmania, nothing seems to be happening with it.