Estimating Gully Erosion Contribution to Large Catchment Sediment Yield Arte in Tanzania
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Date
2009-12
Journal Title
Journal ISSN
Volume Title
Publisher
Elsevier
Abstract
The objective of this paper is to report on the issues and proposed approaches in estimating the contribution
of gully erosion to sediment yield at large catchment. The case study is the upstream of Pangani
River Basin (PRB) located in the North Eastern part of Tanzania. Little has been done by other researchers
to study and/or extrapolate gully erosion results from plot or field scale to large catchment. In this study
multi-temporal aerial photos at selected sampling sites were used to estimate gully size and morphology
changes over time. The laboratory aerial photo interpretation results were groundtruthed. A data mining
tool, Cubist, was used to develop predictive gully density stepwise regression models using aerial photos
and environment variables. The delivery ratio was applied to estimate the sediment yield rate. The spatial
variations of gully density were mapped under Arc View GIS Environment. Gully erosion sediment yield
contribution was estimated as a ratio between gully erosion sediment yield and total sediment yield at
the catchment outlet. The general observation is that gullies are localized features and not continuous
spatially and mostly located on some mountains’ foot slopes. The estimated sediment yield rate from gullies
erosion is 6800 t/year, which is about 1.6% of the long-term total catchment sediment yield rate. The
result is comparable to other study findings in the same catchment. In order to improve the result larger
scale aerial photos and high resolution spatial data on soil-textural class and saturated hydraulic conductivity
– are recommended.
Description
Keywords
Cubist, Data mining tool, Gully erosion, Sediment delivery ratio, Sediment yield
Citation
Ndomba, P.M., Mtalo, F. and Killingtveit, A., 2009. Estimating gully erosion contribution to large catchment sediment yield rate in Tanzania. Physics and Chemistry of the Earth, Parts A/B/C, 34(13), pp.741-748. DOI: 0.1016/j.pce.2009.06.00