Geology Reference
In-Depth Information
Table 19.1
Overview of studies reporting topographic thresholds for incipient gullying in a range of environments.
The topographic threshold is the value of
b
in the relationship
S
=
aA
b
where
S
is the slope gradient of the soil
surface and
A
is the drainage area.
Country
Land use
Value of b
Source
Europe
Belgium
Cropland
−0.30 to −0.40
Vandaele
et al
. (1996)
Belgium: shallow (depth<0.8 m) ephemeral
gullies
Cropland
−0.14
Vanwalleghem
et al
. (2005b)
Belgium: deep (depth>0.8 m) ephemeral
gullies
Cropland
−0.15
Vanwalleghem
et al
. (2005b)
UK (South Downs)
Cropland
−0.25
Boardman (1992)
France
Cropland
−0.40
IGN (1983)
Portugal (Alentejo)
Cropland
−0.35
Vandaele
et al
. (1997)
Portugal (Alentejo)
Cropland
−0.30
Vandekerckhove
et al
. (2000)
Portugal (Alentejo)
Rangeland
−0.41
Vandekerckhove
et al
. (2000)
Portugal (Bragança)
Cropland
−0.23
Vandekerckhove
et al
. (2000)
Spain (Rambla Chortal)
Cropland
−0.13
Vandekerckhove
et al
. (2000)
Spain (Cerro Tonosa)
Cropland
−0.10
Vandekerckhove
et al
. (2000)
Spain (Rambla Chortal)
Cropland
−0.14
Vandekerckhove
et al
. (2000)
Spain (Sierra de Gata)
Rangeland
−0.27
Vandekerckhove
et al
. (2000)
Spain (Almeria)
Rangeland
−0.49
Poesen
et al
. (2002)
Greece (Lesvos)
Rangeland
−0.14
Vandekerckhove
et al
. (2000)
Africa
Ethiopia (Tigray)
Rangeland
−0.50
Nyssen
et al
. (2002)
Tanzania (Makonde Plateau, SE Tanzania)
Rangeland
−0.80
Achten
et al
. (2008)
Tanzania (inland plains, SE Tanzania)
Rangeland
−0.36
Achten
et al
. (2008)
Rwanda
Cropland
−0.60
Moeyersons (2003)
Swaziland
Rangeland
−0.11 to −0.26
Morgan & Mngomezulu (2003)
America
US (Colorado)
Sagebrush and scattered
trees
−0.26
Patton & Schumm (1975)
US (Oregon)
Logged forest
−0.40
Montgomery & Dietrich (1988)
US (Southern Sierra Nevada)
Open oak woodland and
grasslands
−0.60
Montgomery & Dietrich (1988)
US (California)
Coastal prairie
−0.40
Montgomery & Dietrich (1988)
Australia
Australia (New South Wales)
Pasture with sparse
vegetation
−0.63
Prosser and Abernethy (1996)
Australia
Pasture
−0.54
Prosser & Winchester (1996)
Australia (Victoria and New South Wales)
Forest with gullies at road
drain outlets
No topographic
threshold observed
Takken
et al
. (2008)
Asia
China (Shaanxi)
Cropland
−0.24
Wu & Cheng (2005)
China (Inner Mongolia)
Cropland
−0.38
Cheng
et al
. (2006)
China (Shaanxi)
Cropland
−0.30
Cheng
et al
. (2007)
China (Heilongjiang)
Cropland
−0.15
Zhang
et al
. (2007)
