[Music plays]
(Doctor Emmett O’Loughlin) Australian soils were tired
a hundred thousand years ago.
They’ve been clapped out ever since,
they’ve been formed and reformed, they’ve lost their nutrients,
they’ve had their organic matter blown away or washed away,
and with the impact of white settlement
they’ve just become worse and worse.
[Music plays]
[Dr O'Loughlin talking to his colleague]
(Narrator) Emmett O’Loughlin, a CSIRO hydrologist,
and his colleague, Rob Vertessy,
are regularly asked to investigate soil and land degradation problems,
both within Australia and around the world.
Invariably the first thing they look for is how water moves through the landscape.
(Doctor Emmett O’Loughlin) The problems are basically water driven,
water flowing over the soil or through the soil,
blowing out the soil,
that sort of process has to be stopped or interrupted.
(Narrator) When it comes to choosing new sites
for Canberra’s 21st Century suburbs
land rehabilitation is a major consideration.
Emmett O’Loughlin and his team are currently helping local planners
tackle one of the worst examples of land degradation.
[Music plays]
In the year 2010 Halls Creek, to the north of Canberra,
will be covered with thousands of houses,
yet an initial inspection showed that the current state of the land
is unfit for human habitation.
(Doctor Emmett O’Loughlin) It’s a good example of wholesale clearing
of woodland eucalypt forest.
It’s a good example of the pressures caused by overgrazing.
It’s a good example of what happens when we have
soil with poor structure exposed to wind erosion
and water erosion,
and leading to the sort of degradation and gullying that we see there now.
(Unknown Male) I’ve identified this as probably some of the worst erosion
in the A.C.T.
(Narrator) A closer look at the gullies with a public works planner
gave the researchers a clear picture of the full extent of the damage.
(Doctor Emmett O’Loughlin) The gullying in Halls Creek
goes to a depth of something like four metres.
It’s not only eating downwards, it’s eating sidewards,
so that... and not just along the one creek line,
it’s poking out all along the way.
(Unknown Male) You know, this gives you an idea
how quickly this is happening,
we’ve got live trees and they’re falling over.
(Narrator) For Emmett the first step towards rehabilitation
is locating a good topographical map of the area.
The Halls Creek map is fed into a computer along with information on rainfall,
vegetation, and soil properties.
The computer software then calculates slope,
aspect, solar radiation, and upslope catchment areas.
The computer model that handles all of this information is called TOPOG.
The brainchild of Emmett, Rob, and their colleagues,
it’s a comprehensive landscape analyser
which has been streamlined so that it can be used by virtually anyone.
(Doctor Emmett O’Loughlin) Well that’s probably one of the beauties of TOPOG,
TOPOG in its physics is very simple.
It’s an analysis which is sufficient,
but not overly complicated,
that allows us to get to the nitty gritty of what really matters.
(Narrator) Landscape architects joined Emmett and the public works planners
on a second visit to the site.
Emmett recommended TOPOG as the means of repairing Halls Creek quickly,
cheaply, and without mistakes.
(Doctor Emmett O’Loughlin) TOPOG gives us the capability
of being able to manipulate patches of trees in the computer
and manipulate the water use by those trees
and compare them, compare the impact that tree planting say here
will have on an eroded area down here
or an area which might be salinized down here.
Well to orient us all, that one tree hill
is the highest point on this three dimensional picture of the terrain.
(Narrator) TOPOG was accepted and incorporated into the operation
by the Department of Public Works and the landscape architects.
(Doctor Emmett O’Loughlin) Our solution for Halls Creek,
which involved planting trees,
in fact had to be modified by rock outcrops
that must be avoided, by the limits of urban growth,
so by a process of toing and froing between ourselves and the landscape planners
we could optimise a solution which took the hydrology
and those other constraints into account.
(Narrator) Spot tree planting, as recommended by TOPOG,
began in the autumn of 1991.
With the rehabilitation of the Halls Creek area now well underway,
Emmett and Rob could turn their attention to other projects
that required TOPOG analysis.
Currently, just around Canberra,
TOPOG is being used to help maintain drinking water quality,
to solve major soil salinity problems,
and to treat effluent along the Cotter River.
The list of projects and users of TOPOG
is continually expanding, both within Australia and around the world.
[Music plays]