Reclaiming the land (1991)
By July 1st, 1991
Researcher Emmett O’Loughlin and his team tackle a major land rehabilitation problem using TOPOG, a new computer-based system which can provide solutions to such diverse problems as soil erosion, soil salinity and drinking water quality.
[Music plays and image shows a tree in the Halls Creek area]
[Image changes to show Doctor Emmett O’Loughlin]
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.
[Image changes and text appears: The Researchers]
[Image changes to show Doctor Emmett O’Loughlin and Rob Vertessy collecting soil samples]
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.
[Image changes back to Doctor Emmett O’Loughlin]
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.
[Image changes to show an aerial view of Canberra suburbs]
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.
[Image changes to show Doctor Emmett O’Loughlin speaking to a group of men]
[Music plays and the image changes to show a tree in Halls Creek area]
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.
[Image changes to show a group of people viewing the land at Halls Creek]
[Image changes to show various pictures of the Halls Creek area]
[Image changes back to Doctor Emmett O’Loughlin]
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.
[Image changes to show Doctor Emmett O’Loughlin walking through an area of Halls Creek with some men]
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.
[Image changes back to Doctor Emmett O’Loughlin]
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.
[Image changes to show Doctor Emmett O’Loughlin walking through an area of Halls Creek with some men]
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.
[Image changes to show a person working on a topographical map]
The Halls Creek map is fed into a computer along with information on rainfall, vegetation, and soil properties.
[Image changes to show a computer image of the topographic map]
The computer software then calculates slope, aspect, solar radiation, and upslope catchment areas.
[Image changes to Doctor Emmett O’Loughlin and Rob Vertessy looking at a computer screen]
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.
[Image changes back to Doctor Emmett O’Loughlin]
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.
[Image changes to show Doctor Emmett O’Loughlin with a group of people at Halls Creek]
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.
[Image changes back to Doctor Emmett O’Loughlin]
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 (indicating with his hands), or an area which might be salinized down here (indicating with his hands).
[Image changes to show Doctor Emmett O’Loughlin speaking to a group of people]
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.
[Image changes to show Doctor Emmett O’Loughlin speaking to a group of people]
[Image changes back to Doctor Emmett O’Loughlin]
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 sand the landscape planners we could optimise a solution which took the hydrology and those other constraints into account.
[Image changes to show a man spot tree planting at Halls Creek]
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.
[Image changes to show Doctor Emmett O’Loughlin speaking with a group of people]
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.
[Image changes to show a Rob Vertessy working at a computer in the field with Doctor Emmett O’Loughlin]
The list of projects and users of TOPOG is continually expanding, both within Australia and around the world.
[Image changes to show CSIRO logo and text appears: CSIRO Australia. Copyright © 1991]