Spatial and temporal variability of river flows in the degraded semi-arid tropical mountains of northern Ethiopia

Auteur(s) et Affiliation(s)



Description :
This study assesses the runoff from 10 medium-sized catchments in the Geba river basin, a subcatchment of the Nile in the semi-arid degraded northern Ethiopian highlands. Flow depth records were automatically obtained every 10 minutes during the rainy seasons (July-September) of 2004-2007 and converted to continuous runoff discharge records. Cumulative annual runoff depths (46-395 mm) are mainly correlated with rainfall depth. Estimated runoff coefficients (9-47%) are negatively correlated with the areal fraction of limestone outcrops in the catchments, indicating runoff transmission losses. Throughout the rainy season, increases in runoff depth and runoff coefficient were observed, which is partly attributed to an increase in baseflow throughout the season. The majority of the runoff occurs during flash floods. Characteristics of these floods are discussed with some examples, including an exceptionally large flood.


Type de document :
Article de périodique

Source :
Zeitschrift für Geomorphologie, issn : 0372-8854, 2013, vol. 57, n°. 2, p. 143-163, nombre de pages : 21, Références bibliographiques : 37 ref.

Date :
2013

Editeur :
Pays édition : Allemagne, Stuttgart, Gebruder Borntraeger