| dc.description.abstract | Despite being mentioned as an important land degradation process in the Lake
Manyara catchment in Tanzania, little is known about the role of gully erosion
in Lake Manyara catchment. Lake Manyara is a basin with no outflow making it
vulnerable to local sediment dynamics. The biodiversity is high and the
national park that is located in the Lake Manyara catchment is an important
source of income for the region. A combination of fieldwork and modeling
with SWAT was implemented to study gully erosion in the catchment. The
fieldwork measurements consisted of the inserting erosion pins in and around
the gully heads and channels of two different gully systems and measuring
the growth. Additionally, SWAT was used to model the surface runoff and
sediment yield that is transported into one of the two studied gully systems.
Further, SWAT was also implemented to study a scenario in which the
agricultural land cover in the area is increased. The measured sediment mobilization
ranged from 0.01 to 1.71 m3 per month. In the modeled catchment an average
sediment yield which ranged from 4.5 to 15.7 t/ha/yr was found.
For the scenario with increased agricultural land cover, the sediment yield increased
significantly. The exact amount of sediment that ends up in the lake is unknown,
but the current study provides an indication of the magnitude of sediment
erosion in the catchment. | |
