Kachana Pastoral Company filed this report in order to
raise community awareness about loss of biodiversity in the region.
For more photos and further updates please go to the links at the bottom of this page.
The Dunham
River
Part
one:
This summary may seem long-winded to
some, but after all we are facing a predicament that did not develop over
night. Nor will it be solved over night.
Most rainfall-catchment areas that I am
acquainted with in this part of the country are in a similar predicament. There
is a net export of soil and biomass each year. This process increasingly
threatens what biodiversity is still here.
It needs to be stressed that when I
refer to "rainfall-catchment areas" I mean the rugged “back country”
that includes watersheds and upper catchment areas. Not the “downs type”
country which very often is/was floodplain country. I refer primarily to country that belongs to the significant portion of
The backdrop as I understand it:
It is no longer a secret within the
world scientific community that
Depending on which scientists we choose
to believe, it seems that by the time the most recent wave of human occupation
reached the Kimberley (in this case Europeans), the local ecology had
stabilised under the evolved/adapted human behaviour patterns of the
descendants of earlier human migrants. This behaviour included the use of fire.
Once again we can only speculate about the exact nature of these behaviour
patterns. Most of the knowledge has either been lost or become largely
irrelevant as local environments have undergone further massive change as a
direct result of further modification of human behaviour in recent decades.
(Escalating environmental deterioration of large tracts of Out-Back Australia
is a saddening testimony of this, as is the plight of many rural communities.)
In any case the "stability"
of the "pre Captain Cook" environments "sustained" an
annual export of soil contributing to what I heard one member of the Fisheries
Dept call “a marine desert” off our North Australian shores. In addition to
this much carbon was annually exhausted into the atmosphere. The pollutant
nature of vegetation-fires was already being well researched within the scientific
community by the mid nineties.
It is also worth noting that early
missionary reports indicate that
With respect to the rugged upper
rainfall-catchment country which proved to be unsuitable for financially viable
beef enterprises, the biggest single factor to induce "environmental
change" was in all probability the cessation of “traditional burning”.
This led to perennial grasses either being excessively "rested" (=
not pruned and therefore becoming senescent) and/or being subjected to hot
burns. There is ample scientific evidence on several continents that neither of
these two practices is conducive to plant-health or an effective water cycle
(emphasis on the biological component).
Through plain ignorance and a general
lack of environmental literacy a disproportionate amount of blame is being
thrown at introduced species or those who try and manage them. From an
ecological aspect it could easily be argued that introduced herbivores turned
feral contribute more to a visual impact through aggravating localised soil
erosion, than they do to the loss of biodiversity. (I am not advocating the
protection of feral animals by any means. I am merely implying that we may well
be able to use them to advantage by recognising their functional roles within
nature and then attempting to influence their behaviour accordingly. Cull
animals produced by industry could be put to better use in a similar fashion.)
Current situational info.
The deterioration of the
In this case the “taps” shut off just as
the tub was beginning to overflow on one side (photos available). The rate with
which the water flowed being a direct result of a close to non-effective
water-cycle in upper-catchment areas. (I refer in particular to the biological
facet of the water-cycle: the role of plant litter and healthy root-systems to
retain and percolate the water and later transpiration.) The "face-towel
partially obstructing the drain" is the result over time of nutrient-rich
tail-water perennially feeding into the lower Dunham from the Packsaddle Plains
irrigation area. This has led to prolonged growth periods and higher plant
vigour in that area. This build-up of vegetation in the drainage channels of
the lower Dunham slows the flow sufficiently to make it drop a higher portion
of its sediment load in that area. Increasingly we notice the choking up of
drainage lines. This process is of course greatly aided by the geographical
features of that area. Apart from what can easily be observed and monitored on
site there is further evidence for this development. Tributaries just upstream
of the described areas have dropped much of their silt-load on site and gully
development has stopped taking its natural course. This is due to everything
being under water. Subsequent drainage was "slow" enough to
significantly reduce the further gouging out of gullies. It is also evident
that the Dunham did have another course running due east at some point in time.
I will not speculate as to when that was, but the fact that water actually ran
that direction last week tells me enough.
Flooding to date and future flooding in
the area south west of Packsaddle plains is merely a symptom indicating the
compounding effects of management practices (over time) both at the lower end
as well as the upper end of the Dunham. ( http://www.abc.net.au/kimberley/stories/s492225.htm ) I
believe Allan Savory would attribute the root cause to conventional
decision-making and I second that. Either way it seems most unlikely that the
Kununurra community will escape the law of the harvest. (Statisticians may very
well calculate that the probability of a repeat performance of last week’s
rainfall events plus the additional 5-inch storm is a very low risk. However
with a continued rate of decline in upper catchment health it is more a
question of “when” than “whether”. Possible obvious band-aid solutions to free
up the drainage may buy us some time, but they will not detract from what is
happening up this end.)
The Kununurra community should thank
Roy Wilson (who manages cattle on Doon Doon) for the precautionary burning he
conducted in the upper Dunham catchment last year. Much as I believe that
current burning practices are not sustainable, there is little doubt in my mind
that had he not done so, the same amount of water would have been released
through the Dunham Gorge in a much shorter time frame. I have no details of the
costs to repair damage to physical infrastructure downstream, but if it had not
been for
In the absence of effective regional
“river-catchment strategies”, there will be a continued need for managers like
Roy and myself to reduce excessive fuel loads with fire. So long as this is the
case the “problem” of the Dunham will not go away.
By Chris Henggeler, land manager,
Kachana (2002-02-27)
Part
two:
The more environmentally literate
reader may challenge the logic behind my presumption that
A late dry-season “scorcher” used to be
close to a certainty in that area. Had this been the case late 2001, run-off
early 2002 would have been significantly higher.
I believe
If people like
As somebody who burns much biomass
every year, I will argue that this is the ecological premium that we need to
pay for insurance on our commercial and other activities. I cannot see this method to be sustainable.
If we wish to effectively address the
down-stream symptoms of poor water-cycles, I strongly encourage that “the
powers that be” offer people like Roy (who have spent their whole life in the
bush) the opportunity to explore animal maintained landscapes.
By Chris Henggeler, land manager,
Kachana (2002-02-27)
Part
three:
If we wish to apply the cautionary
principle, perhaps now is a good time to begin?
It is close to the end of the dry season
and there has been a change in management in the upper Dunham area. On Doon
Doon the first page of the next chapter of further flooding of the
·
Firstly mustering the upper Dunham region has been made
easier. (One would have to be most surprised if more than fifty head of cattle were
caught over and above the number that could have been caught without burning.)
·
Secondly Roy Wilson's work of the last few years has been
written off.
Who will be faced the financial and
social costs of crisis management?
Are we in a position to gauge the
ecological costs associated with atmospheric pollution, loss of nutrients and
biomass and a further compromise of the water cycle and the energy flow?
The sad part is that what the mustering
contractor did is both politically correct and still standard practice in many
areas of
Fire may well be the physical force
that attracts so much research, however in the reality beyond our taxpayer
funded trials, both the cause and the effect of fire remain a social issue.
It is increasingly apparent that the
health of the
In times of fiscal restraint and in the
absence of a landscape goal it seems there is little that will be done about
the health of the Dunham. Fortunately the path of a flooding river is easier to
predict than the path of a cyclone. As for the timing of such an event….during
a wet season would be a safe bet.
( http://www.abc.net.au/kimberley/stories/s492225.htm )
By Chris Henggeler, land manager,
Kachana (2002-10-22)
Dunham River Water Catchment update: Dry-season 2003
The Dunham River issue: September 2004
Kachana Pastoral Company promoting environmental literacy and functional
science:
www.environmental-literacy.com (Learning to read what
Nature is telling us now.)
So
what exactly do we mean by "Environmental Literacy"?
The
link above takes you to a two-page summary of:
·
What we think it means and what it does not
mean
·
How we hope to do our part in meeting the
challenges we all face
GRASS
ROOTS INPUT TO ENVIRONMENTAL DEBATES