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Accueil du site → Doctorat → Belgique → Assessment of spatial and temporal variability of river discharge, sediment yield and sediment-fixed nutrient export in Geba River catchment, northern Ethiopia

Katholieke Universiteit Leuven (2009)

Assessment of spatial and temporal variability of river discharge, sediment yield and sediment-fixed nutrient export in Geba River catchment, northern Ethiopia

Amanuel Zenebe Abraha

Titre : Assessment of spatial and temporal variability of river discharge, sediment yield and sediment-fixed nutrient export in Geba River catchment, northern Ethiopia

Auteur : Amanuel Zenebe Abraha

Université de soutenance : Katholieke Universiteit Leuven

Grade : Doctor of Philosophy (PhD) 2009

Présentation)
Soil erosion by water is one of the most important land degradation processes in the Northern Ethiopian highlands. Studies on river discharge, sediment yield, and sediment characteristics at the intermediate catchment scale (100 – 10 000 km2) are however hardly available in the Ethiopian highlands. Nevertheless, huge investments are made for dam construction works in this region. Due to a lack of reliable hydrological data many dams and reservoirs have been overdimensioned. Likewise, many reservoirs fill up with sediments at an alarming rate because of the underestimation of sediment yield. Moreover, nutrients associated with sediment loss are often not considered. This research aimed at a better understanding of the spatial and temporal variation of river discharge, sediment yield and sediment characteristics and to link their variation to catchment characteristics.
Measurements were conducted in 10 sub-catchments (121 – 4331 km²) of the Geba river, a tributary of the Tekeze. The Geba catchment is a representative catchment for the Northern Ethiopian Highlands. Pressure transducers and staff gauges were used to measure the river flow depths on a continuous basis. Depth-integrated suspended sediment samples (n = 2714) were taken at ten monitoring stations in the Geba catchment from 2004 to 2007. Rating curves were established to estimate runoff discharge, sediment yield and sediment fixed-nutrient export. Suspended sediment characteristics (texture, N, Pav and K) of 213 samples were analyzed. The river discharge and sediment yield has been related to the major bio-physical catchment characteristics

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Page publiée le 25 octobre 2016, mise à jour le 25 janvier 2017