Assessment of Geomorphologic Impacts of Channel Erosion in River Tisa Basin in Ambasel District, Northeastern Ethiopia

Abstract

The geomorphological impacts of channel erosion in streams that flank from Ambasel ridge  of  Mile  drainage basin( which is one of the upstream of Awash river) were examined. Data were generated through direct field measurement and observation of some geomorphological variables of the cross sectional channel width and channel depth dimensions. The basic equipment employed for data generation is the tape, a piece of tie rod and ranging poles. The data generated were analyzed and processed by  descriptive statistics such as the mean, standard deviation, range and simple percentages while the Student’s‘t’ and Snedecor’s F tests were also used as the basic inferential statistics for testing the hypothesis generated. The result of the analysis showed that the geomorphological impacts of erosion in the Ambasel ridge and its low-lying area varied spatially both across and along the profiles of the streams. However, such impacts were more pronounced in the upstream of the drainage basin. The study uncovered further impact of channel erosion to include channel bank collapse and in-caving, destruction of habitat structure, degradation of farmlands in the low-lying areas by sediment invasion over the farm lands. The way forward is land use zoning agriculture and channelization tracing the natural sinuosity of the river as some of the measures for controlling the undesirable effect of channel erosion in the drainage basin.

Keywords: Spatial Analysis, Geomorphic Impacts, Channel Erosion, Ambasel District