Geology Reference
In-Depth Information
developing testing methodologies (Willgoose
et al ., 2003; Hancock, 2003).
In particular there is a need for a tool with an
easy-to-use interface, which is well documented,
computationally robust, widely validated on the
types of problems of interest, contains all the
physics that might be needed for typical appli-
cations, and with a database of erosion para-
meters (e.g. using pedo-transfer functions). No
LEM currently available meets all of these needs.
Coulthard (2001) in a recent review, albeit aimed
at a research audience, indicated that the first
author's EAMS-SIBERIA rehabilitation design
package most closely met these criteria. This
reflects the wide range of (mainly) mine rehabilita-
tion case studies on which it has been applied. It is
anticipated that a new model, TelluSim, will super-
sede EAMS-SIBERIA in the near future (Willgoose,
2009). This new model will facilitate new applica-
tions in new areas and will make it easier to cus-
tomize for specific applications and user needs.
However, as we have noted there are other exam-
ples of erosion where the very act of modelling the
landform evolution draws out features of the ero-
sion process that are not explicated by traditional
approaches. These revolve around the design of
optimal landform - landforms that are in equilib-
rium with the erosion processes occurring on
them. LEMs have quantified the rules for the shape
of the landform that is required. This has elimi-
nated the risky step of simply assuming that the
best shape for a constructed slope is the same as
the adjacent natural slope. LEMs have shown that
if the soil materials are different, then the shape of
the hillslope required is likely to be different.
Finally we have discussed how the evolution of
the landform itself can be used as a way of protecting
a site by the use of selective armouring of the sur-
face. By using selective armouring on hillslopes we
can reduce long-term hillslope erosion markedly,
while avoiding the costly step of armouring the
entire slope to provide erosion protection.
Acknowledgements
18.7 Conclusions
The first author is currently funded by an
Australian Research Council Australian Profes-
sorial Fellowship (APF). Work described in this
chapter has been funded by the Queensland Coal
Association, Environmental Research Institute of
the Supervising Scientist (eriss), Energy Resour-
ces of Australia, Rio Tinto and the Australian
Research Council.
Landform evolution models (LEMs) are emerging
as a practical tool for simulating erosion for a
range of problems that are not possible for tradi-
tional erosion models to address. Broadly speak-
ing these problems are ones where features that
take some time to develop (e.g. gullies), which
develop only in response to erosion, and where
the features are critical to the success or other-
wise of the project. The authors' experience is
mostly in the area of mine rehabilitation, waste
containment and nuclear waste repositories. In
these cases failure occurs when the maximum
depth of erosion incision reaches the waste. In
these cases it is the maximum depth of incision
of gullies and valleys that develop on the land-
form rather than the average erosion that is criti-
cal. LEMs are ideally suited to address this type of
problem because of their ability to model the
incision process over time. This localized inci-
sion is a key part of the development of hills and
valleys in landform evolution.
References
Ahnert, F. (1976) Brief description of a comprehensive
three-dimensional process-response model for land-
form development. Zeitschrift für Geomorphologie
N.F. Supplement 25 : 29-49.
Ahnert, F. (1984) Local relief and the height limits of
mountain ranges. American Journal of Science 204 :
1035-55.
Bell, J.R.W. & Willgoose, G.R. (1998) Monitoring of
gully erosion at ERA Ranger Uranium Mine, Northern
Territory, Australia . Internal Report 274, Environ-
mental Research Institute of the Supervising Scientist,
Jabiru, NT, Australia.
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