Adgo, Enyew

Bodé, Samuel

Boeckx, Pascal

Deffersha, Habtamu Assaye

Frankl, Amaury

Meshesha, Derege

Nyssen, Jan

Poesen, Jean

Wassie, Alemayehu

Ghent University Academic Bibliography

Geophysical Research AbstractsVol. 21, EGU2019-4011, 2019EGU General Assembly 2019© Author(s) 2019. CC Attribution 4.0 license.Quantifying source-specific sediment fluxes in rehabilitating catchmentsin the Lake Tana Basin of northwest EthiopiaHabtamu Assaye (1,2), Samuel Bodé (3), Alemayehu Wassie (2), Derege Meshesha (2), Enyew Adgo (2), JeanPoesen (4), Jan Nyssen (1), Pascal Boeckx (3), Amaury Frankl (1,5)(1) Ghent University, Faculty of Sciences, Geography, Belgium (habtamuassaye.deffersha@ugent.be), (2) Department ofNatural Resource Management, Bahir Dar University, Bahir Dar, Ethiopia, (3) Department of Green Chemistry andTechnology, Ghent University, Ghent, Belgium, (4) Department of Earth and Environmental Sciences, KU Leuven, Heverlee,Belgium, (5) Research Foundation Flanders (FWO), Brussels, BelgiumThe Lake Tana Basin suffers from soil erosion and sediment fluxes to the Lake threatens its ecology and storagecapacity by siltation. Soil erosion control measures are often not successful as upland erosion processes andsediment sources are not properly understood. In this study, we aimed at understanding sediment sources andfluxes by integrating fingerprinting and catchment sediment yield measurements. As a proof of concept, weselected two small catchments (60 ha and 76 ha) within a 10.4 km2 study area near the town of Arb Gebeya.At the outlets, sharp-crested rectangular weirs were installed to quantify runoff and suspended sediment fluxes.Therefore, the water stage was measured at the weirs at five-minute interval using a TD-Diver and suspendedsediment was sampled in the morning and during peak runoff events. Phillips tube sediment samplers werealso installed at the catchment outlets to collect time-integrated sediment samples. Within the two catchments,75 soil samples were collected from five land use classes and gully banks. A compound specific stable isotope(CSSI) finger printing technique was used to apportion sediment sources using δ13C of plant derived fatty acids(δ13C–FAs). Gas chromatograph-combustion-isotope ratio mass spectrometry (GC-C-IRMS) was used to measurethis isotopic signature and MixSIAR, a FA-content dependent, Bayesian-stable isotope mixing models was usedto determine the proportional contribution of the different sediment sources to the sediment mixture. Finally,source-specific catchment sediment budget was determined and sediment fluxes were analyzed in relation tocatchment connectivity. Primary results revealed that percent vegetation cover of a catchment strongly influencesrunoff and sediment yield processes.Keywords: Catchment, land uses, connectivity, fingerprinting, sediment yield

Quantifying source-specific sediment fluxes in rehabilitating catchments in the Lake Tana Basin of northwest Ethiopia

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Quantifying source-specific sediment fluxes in rehabilitating catchments in the Lake Tana Basin of northwest Ethiopia

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