Print Email Facebook Twitter Change in low flows due to catchment management dynamics—Application of a comparative modelling approach Title Change in low flows due to catchment management dynamics—Application of a comparative modelling approach Author Gebremicael, T.G. (TU Delft Water Resources; IHE Delft Institute for Water Education; Tigray Agricultural Research Institute) van der Zaag, P. (TU Delft Water Resources; IHE Delft Institute for Water Education) Abbas Mohamedali, Y. (TU Delft Water Resources; IHE Delft Institute for Water Education; Hydraulic Research Station) Hagos, Eyasu Y. (Mekelle University) Date 2020 Abstract Understanding the natural low flow of a catchment is critical for effective water management policy in semi-arid and arid lands. The Geba catchment in Ethiopia, forming the headwaters of Tekeze-Atbara basin was known for its severe land degradation before the recent large scale Soil and Water conservation (SWC) programs. Such interventions can modify the hydrological processes by changing the partitioning of the incoming rainfall on the land surface. However, the literature lacks studies to quantify the hydrological impacts of these interventions in the semi-arid catchments of the Nile basin. Statistical test and Indicators of Hydrological Alteration (IHA) were used to identify the trends of streamflow in two comparatives adjacent (one treated with intensive SWC intervention and control with fewer interventions) catchments. A distributed hydrological model was developed to understand the differences in hydrological processes of the two catchments. The statistical and IHA tools showed that the low flow in the treated catchment has significantly increased while considerably decreased in the control catchment. Comparative analysis confirmed that the low flow in the catchment with intensive SWC works was greater than that of the control by >30% while the direct runoff was lower by >120%. This implies a large proportion of the rainfall in the treated catchment is infiltrated and recharge aquifers which subsequently contribute to streamflow during the dry season. The proportion of soil storage was more than double compared to the control catchment. Moreover, hydrological response comparison from pre- and post-intervention showed that a drastic reduction in direct runoff (>84%) has improved the low flow by >55%. This strongly suggests that the ongoing intensive SWC works have significantly improved the low flows while it contributed to the reduction of total streamflow in the catchment. Subject catchment managementGeba catchmenthydrological processeslow flowsoil and water conservationTekeze-Atbara River basin To reference this document use: http://resolver.tudelft.nl/uuid:c0e8b361-7bb2-4da5-946c-3f2f946d19f3 DOI https://doi.org/10.1002/hyp.13715 ISSN 0885-6087 Source Hydrological Processes, 34 (9), 2101-2116 Part of collection Institutional Repository Document type journal article Rights © 2020 T.G. Gebremicael, P. van der Zaag, Y. Abbas Mohamedali, Eyasu Y. Hagos Files PDF hyp.13715.pdf 4.85 MB Close viewer /islandora/object/uuid:c0e8b361-7bb2-4da5-946c-3f2f946d19f3/datastream/OBJ/view