Chapter 19
Applied geomorphology and arid regions
1. Introduction
The applied geomorphology of desert areas is not very different from that of other
morphoclimatic areas, although it does have some peculiarities. The lack of water, scant or
zero plant cover and much eroded soils leave the regolith with no efficient protection
against the action of atmospheric agents (Tricart, 1969). The most important processes in
arid areas are wetting and drying, salt weathering, water erosion, channel changes,
flooding, and wind erosion.
Practical studies on arid regions are important because of the extraordinary extension of
these environments; the world's two largest morphogenetic systems are those made up by
the arid and cold regions. It is difficult, however, to generalize about the effects of
geomorphology in these areas because of their great climatic, geological and tectonic
differences. Further, these regions are usually underdeveloped and scantily populated, and
data on even their basic features, such as their climatic and hydrological characteristics,
are few and geographically disperse. In most cases, the only data available come from a
few rare and rather specific studies (Guti6rrez and Sancho, 1993).
In 1979, the population of the world's arid areas - 651 million - was 15 per cent
of the planetary total. Between 1960 and 1974, however, an increase of 63.5 per cent
was experienced. Some 1200 million people inhabited these regions by the year 2000.
This population is distributed mainly as large concentrations; there are 355 cities
over the world's arid regions with more than 100,000 inhabitants, although most of
them are in Asia. The geomorphological and environmental problems caused by the
expansion of these cities are numerous (Cooke et al., 1982; Goudie, 1990a,b;
O'Hara, 1997).
Many of the landforms of these dry regions were generated under climatic conditions
different to those of the present day. A detailed study is therefore needed to differentiate
between those shaped by modem processes and those that are relicts of earlier times
(Guti~rrez, 1986). It is also important to decide on the basis and goals of any practical
geomorphological study to be performed in a desert region. This has been clearly stated by
Cooke (1977):
Applied geomorphology in deserts is primarily concerned with the survey and evaluation of
landforms, superficial materials and processes, and with managing, monitoring and predicting
landform and process changes. It relates to practical problems in which geomorphological
information normally only forms a part of the required body of knowledge, and its
philosophical basis (in so far as it exists independently of "pure" geomorphology) is
inevitably dictated by the demands of specific problems. Axiomatically, the applied desert
geomorphologist must be able to talk to and work with those in other cognate disciplines, and
Applied geomorphology and arid regions
1. Introduction
The applied geomorphology of desert areas is not very different from that of other
morphoclimatic areas, although it does have some peculiarities. The lack of water, scant or
zero plant cover and much eroded soils leave the regolith with no efficient protection
against the action of atmospheric agents (Tricart, 1969). The most important processes in
arid areas are wetting and drying, salt weathering, water erosion, channel changes,
flooding, and wind erosion.
Practical studies on arid regions are important because of the extraordinary extension of
these environments; the world's two largest morphogenetic systems are those made up by
the arid and cold regions. It is difficult, however, to generalize about the effects of
geomorphology in these areas because of their great climatic, geological and tectonic
differences. Further, these regions are usually underdeveloped and scantily populated, and
data on even their basic features, such as their climatic and hydrological characteristics,
are few and geographically disperse. In most cases, the only data available come from a
few rare and rather specific studies (Guti6rrez and Sancho, 1993).
In 1979, the population of the world's arid areas - 651 million - was 15 per cent
of the planetary total. Between 1960 and 1974, however, an increase of 63.5 per cent
was experienced. Some 1200 million people inhabited these regions by the year 2000.
This population is distributed mainly as large concentrations; there are 355 cities
over the world's arid regions with more than 100,000 inhabitants, although most of
them are in Asia. The geomorphological and environmental problems caused by the
expansion of these cities are numerous (Cooke et al., 1982; Goudie, 1990a,b;
O'Hara, 1997).
Many of the landforms of these dry regions were generated under climatic conditions
different to those of the present day. A detailed study is therefore needed to differentiate
between those shaped by modem processes and those that are relicts of earlier times
(Guti~rrez, 1986). It is also important to decide on the basis and goals of any practical
geomorphological study to be performed in a desert region. This has been clearly stated by
Cooke (1977):
Applied geomorphology in deserts is primarily concerned with the survey and evaluation of
landforms, superficial materials and processes, and with managing, monitoring and predicting
landform and process changes. It relates to practical problems in which geomorphological
information normally only forms a part of the required body of knowledge, and its
philosophical basis (in so far as it exists independently of "pure" geomorphology) is
inevitably dictated by the demands of specific problems. Axiomatically, the applied desert
geomorphologist must be able to talk to and work with those in other cognate disciplines, and