Your search found 4 records
1 Nyssen, J.; Descheemaeker, Katrien; Zenebe, A.; Poesen, J.; Deckers, J.; Haile, M. 2009. Transhumance in the Tigray Highlands (Ethiopia) Mountain Research and Development, 29(3):255-264. [doi: https://doi.org/10.1659/mrd.00033]
Highlands ; Grazing lands ; Pastures ; Livestock ; Rangelands ; Transhumance / Ethiopia / Tigray Highlands
(Location: IWMI HQ Call no: e-copy only Record No: H042534)
(0.80 MB)
Transhumance, the seasonal movement of herds occurring between two points and following precise routes repeated each year, is practiced on a broad scale in the open field areas of Tigray (North Ethiopia). This article presents a characterization of the practice, factors that explain its magnitude, and recent changes. Eleven villages were selected randomly, semistructured interviews were conducted, and data on the sites were collected both in the field and from secondary sources. The transhumance destination zones are characterized as better endowed with water and fodder resources, essentially due to their great extent. The sample villages can be classified into three groups: annual transhumance (average one-way traveling distance 8.1 km), home range herding (average traveling distance 2.2 km), and keeping livestock near homesteads. Movements are basically induced by the fact that there is little to no space for livestock near the villages during the crop-growing period—not by the significantly different temperature or rainfall conditions in the grazing lands. Adults will only herd the flocks when the distance for transhumance is great or considered unsafe; otherwise, young boys tend the livestock for the entire summer rainy season. Faced with social (schooling) and technological (reservoir construction and establishment of exclosures) changes, transhumance in Tigray has adjusted in a highly adaptive way, with new routes being developed and others abandoned. Transhumance does not lead to major conflicts in the study area even when livestock are brought to areas that belong to other ethnic groups (Afar, Amhara).
2 Nyssen, J.; Clymans, W.; Descheemaeker, Katrien; Poesen, J.; Vandecasteele, I.; Vanmaercke, M.; Zenebe, A.; Van Camp, M.; Haile, M.; Haregeweyn, N.; Moeyersons, J.; Martens, K.; Gebreyohannes, T.; Deckers, J.; Walraevens, K. 2010. Impact of soil and water conservation measures on catchment hydrological response: a case in north Ethiopia. Hydrological Processes, 24(13):1880-1895. [doi: https://doi.org/10.1002/hyp.7628]
Catchment areas ; Water conservation ; Soil conservation ; Hydrology ; Runoff ; Water table ; Measurement ; Water balance / Ethiopia
(Location: IWMI HQ Call no: e-copy only Record No: H042876)
(0.59 MB)
Impact studies of catchment management in the developing world rarely include detailed hydrological components. Here, changes in the hydrological response of a 200-ha catchment in north Ethiopia are investigated. The management included various soil and water conservation measures such as the construction of dry masonry stone bunds and check dams, the abandonment of post-harvest grazing, and the establishment of woody vegetation. Measurements at the catchment outlet indicated a runoff depth of 5 mm or a runoff coefficient (RC) of 1Ð6% in the rainy season of 2006. Combined with runoff measurements at plot scale, this allowed calculating the runoff curve number (CN) for various land uses and land management techniques. The pre-implementation runoff depth was then predicted using the CN values and a ponding adjustment factor, representing the abstraction of runoff induced by the 242 check dams in gullies. Using the 2006 rainfall depths, the runoff depth for the 2000 land management situation was predicted to be 26Ð5 mm (RC D 8%), in line with current RCs of nearby catchments. Monitoring of the ground water level indicated a rise after catchment management. The yearly rise in water table after the onset of the rains ( T) relative to the water surplus (WS) over the same period increased between 2002–2003 ( T/WS D 3Ð4) and 2006 ( T/WS >11Ð1). Emerging wells and irrigation are other indicators for improved water supply in the managed catchment. Cropped fields in the gullies indicate that farmers are less frightened for the destructive effects of flash floods. Due to increased soil water content, the crop growing period is prolonged. It can be concluded that this catchment management has resulted in a higher infiltration rate and a reduction of direct runoff volume by 81% which has had a positive influence on the catchment water balance.
3 Negash, E.; Gebresamuel, G.; Embaye, T.-A. G.; Zenebe, A.. 2019. The effect of climate and land-cover changes on runoff response in Guguf Spate Systems, northern Ethiopia. Irrigation and Drainage, 68(3):399-408. [doi: https://doi.org/10.1002/ird.2326]
Climate change ; Land cover change ; Rainfall-runoff relationships ; Irrigation systems ; Semiarid zones ; Soil moisture ; Evapotranspiration ; Hydrological factors ; Catchment areas / Ethiopia / Guguf Catchment
(Location: IWMI HQ Call no: e-copy only Record No: H049265)
(1.40 MB)
Irrigated agriculture in the rainfall-deficit semi-arid lowlands of the Raya valley rely on spate systems to produce food crops. Climate and land-cover dynamics upstream are, however, threatening runoff response reaching these spate systems. The objective of this study was thus to analyse the hydrological response of dryland catchments to changing climate and land cover in Guguf spate systems. Thirty-six years of climate data were analysed using Mann–Kendall, Pettitt's test and linear regression methods, and time-series land-cover information extracted from Landsat satellite images in a remote-sensing interface. The Soil Conservation Systems curve number method was then employed to formulate the likely impact of climate and land-cover changes on runoff response, and trends analysed. Results showed that temperature, evapotranspiration and rainfall varied at least by 0.11°C, 15.2 mm and -5.1 mm yr-1 respectively, intensifying moisture stress. Moreover, improving vegetation cover in the highlands enhanced the water-abstraction capacity of the soil, impeding the runoff curve number by 9.2%. Thus, the combined effects of climate induced moisture stress and land cover led water abstraction upstream has threatened runoff response at a rate of 0.23 × 106 m3 yr-1. In other words, the runoff response reaching Guguf spate systems degenerated by 7.96 × 106 m3 over 36 years. Such unusual highland–lowland hydrological linkage has therefore endangered the availability of surplus water to irrigate spate-based farms downstream. Appropriate policies and strategies would therefore be desirable to address conflicting interests in scarce water resources in the face of climate change.
4 Negash, E.; Gebresamuel, G.; Embaye, T.-A.; Nguvulu, A.; Meaza, H.; Gebrehiwot, M.; Demissie, B.; Gebreyohannes, T.; Nyssen, J.; Zenebe, A.. 2020. Impact of headwater hydrological deficit on the downstream flood-based farming system in northern Ethiopia. Irrigation and Drainage, 69(3):342-351. [doi: https://doi.org/10.1002/ird.2413]
Irrigation systems ; Flood irrigation ; Farming systems ; Flash flooding ; Irrigated farming ; Hydrology ; Water deficit ; Crop production ; Evapotranspiration ; Land cover ; Downstream / Ethiopia / Guguf
(Location: IWMI HQ Call no: e-copy only Record No: H049847)
(0.37 MB)
Flood-based farming is a means of improving crop production in rain-deficit lowlands. Such spate irrigation systems are growing in importance, although the effects of headwater hydrological deficit on downstream flood farming are lacking evidence. This study investigates the impacts of headwater hydrological deficit on the extent of spate-irrigated agriculture in the Guguf spate system. The length of canals and area of spate-irrigated agriculture to the right and left of the Guguf River for the 1980s and 2010s were tracked using a global positioning system and mapped in a geographic information system interface, while climate data were collected from National Meteorological Agency. Trends of selected hydroclimatic variables were analysed using linear regression and the Pettitt test. The flash floods have shrunk by 7.36 × 106 m3, as a result of which the length of canals and area of spate-based farms declined by 1.37 km and 1540 ha, i.e. 35 and 57.5%, respectively, in only three decades. This corresponds to an average withdrawal of -44.0 ha yr ¹. A single 1 million m3 decline in flash floods caused a 366.4 ha decline in spate-based farms. Moreover, farm fields located next to the river course are less affected, compared to those at the tail of the scheme. If the current trend continues, there is a high risk that the remaining farms currently receiving floods may find themselves outside of the spate systems. Therefore, we suggest that flood management technologies are needed to optimize the efficiency of soil moisture in the spate system.
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