Assessment of gully erosion using photogrammetric techniques. A case study of upper Mbuluzi river, Swaziland
Fecha
2007Versión
Acceso abierto / Sarbide irekia
Tipo
Contribución a congreso / Biltzarrerako ekarpena
Versión
Versión publicada / Argitaratu den bertsioa
Impacto
|
nodoi-noplumx
|
Resumen
Swaziland is severely affected by gully erosion contributing
to a sediment budget up to 250,000 m3 y-1 (WMS Associates,
1988). This type is more important than inter-rill and rill
erosion. Severe gully erosion is mainly in the Middleveld
especially on communal land highly populated (43.65
inhabitants km-2) and with high livestock concentrations.
Here, the calculated carrying capacities are 0.27 L ...
[++]
Swaziland is severely affected by gully erosion contributing
to a sediment budget up to 250,000 m3 y-1 (WMS Associates,
1988). This type is more important than inter-rill and rill
erosion. Severe gully erosion is mainly in the Middleveld
especially on communal land highly populated (43.65
inhabitants km-2) and with high livestock concentrations.
Here, the calculated carrying capacities are 0.27 LSU ha-1
(Livestock Units) vs. stocking rates 0.87 LSU ha-1.
In general, to assess gully erosion, numerous investigators
have made use of aerial photos and GIS to predict the
morphometric conditions that favoured gulling (Nachtergaele
and Poesen, 1999).
In Swaziland, from 1947 to 1987, the WMS Associates
(1988) established gully erosion rates from aerial stereo
photos. Subsequently, Mushala et al., 1994 analyzed the
gullies distribution and their relationship to lithology and
land tenure.
In the present research long terms rates of gully erosion
have been measured by aerial photos taken from 1947 to
1996. Particular attention was focused on two dendritic
gully systems. One of them is dynamically evolving,
whereas the other one is in a static phase (Sidorchuk, 1999).
The objectives of this research were to calculate the
historical development of the morphology of gully as input
data to the gully erosion model (Sidorchuk et al., 2001) and
to predict hillslope area susceptible to gulling. A High
Digital Terrain Models (HDTMs) with 1-m resolution were
devised for this purpose. [--]
Materias
Gully erosion,
Mbuluzi river (Swaziland)
Editor
Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
Publicado en
Javier Casalí, Rafael Giménez (eds.): Progress in Gully Erosion Research. IV International Symposium on Gully Erosion. September 17-19, 2007. Pamplona, Spain. Pamplona: Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa, 2007
Notas
Resumen del trabajo presentado al IV International Symposium on Gully Erosion, celebrado en la Universidad Pública de Navarra del 17 al 19 de septiembre de 2007.
Entidades Financiadoras
Part of this work was supported by the European
Union, INCO-DC, contract nr. IC18-CT97-0144.