Your search found 14 records
1 Nyssen, J.; Haile, M.; Descheemaeker, K.; Deckers, J.; Poesen, J.; Moeyersons, J.; Hailemariam, T. 2003. Promoting global watershed management towards rural communities: the May Zeg-zeg initiative. In McCornick, P. G.; Kamara, A. B.; Tadesse, G. (Eds). Integrated water and land management research and capacity building priorities for Ethiopia: proceedings of a MoWR/EARO/IWMI/ILRI International Workshop held at ILRI, Addis Ababa, Ethiopia, 2-4 December 2002. Nairobi, Kenya: International Livestock Research Institute (ILRI); Colombo, Sri Lanka: International Water Management Institute (IWMI); Addis Ababa, Ethiopia: Ethiopian Ministry of Water Resources; Addis Ababa, Ethiopia: Ethiopian Agricultural Research Organization. pp.192-195.
(Location: IWMI-HQ Call no: IWMI 333.91 G636 MCC Record No: H032462)
2 Nyssen, J.; Poesen, J.; Descheemaeker, Katrien; Haregeweyn, N.; Haile, M.; Moeyersons, J.; Frankl, A.; Govers, G.; Munro, N.; Deckers, J. 2008. Effects of region-wide soil and water conservation in semi-arid areas: the case of northern Ethiopia. Zeitschrift für Geomorphologie, 52(3):291-315.
(Location: IWMI HQ Call no: e-copy only Record No: H041844)
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Studies on the impacts of environmental rehabilitation in semi-arid areas are often conducted over limited space and time scales, and do typically not include detailed biophysical components. This study makes a multi-scale assessment over a time span of 30 years of environmental rehabilitation in one of the world's most degraded areas: the Tigray highlands of Northern Ethiopia. The study shows that in Tigray sheet and rill erosion rates have decreased by approximately 68%, infiltration and spring discharge are enhanced and vegetation cover has improved. These impacts are evidenced and quantified by a comprehensive comparison of the current landscape with a coverage of 30-year old photographs and substantiated by field investigations. The positive changes in ecosystem service supply that result from these conservation activities in the Tigray highlands are an issue of global concern.
3 Descheemaeker, Katrien; Poesen, J.; Borselli, L.; Nyssen, J.; Raes, D.; Haile, M.; Muys, B.; Deckers, J. 2008. Runoff curve numbers for steep hillslopes with natural vegetation in semi-arid tropical highlands, northern Ethiopia. Hydrological Processes, 22:4097-4105.
(Location: IWMI HQ Call no: e-copy only Record No: H041539)
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Daily runoff from 27 plots (5 m ð 2 m) recorded during two rainy seasons in the Tigray highlands (Ethiopia) were analysed together with daily rainfall to calculate runoff curve numbers for hillslopes covered by semi-natural vegetation in varying stages of vegetation restoration. Curve number model parameters were derived using a least squares fitting procedure on the collected rainfall–runoff datasets. Curve numbers varied from 29 to 97. Land use type was an important explanatory factor for the variation in curve numbers, whereas hydrologic soil group was not. Curve numbers were negatively correlated with vegetation cover. Taking into account antecedent soil moisture conditions did not improve runoff prediction using the curve number method. As runoff prediction was less accurate in areas with low curve numbers, two separate regression functions relating curve numbers with vegetation cover were proposed for different land use types.
(Location: IWMI HQ Call no: IWMI 636 100 AME Record No: H042211)
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The establishment of exclosures (i.e. areas closed for grazing and agriculture) is a common practice to reverse land degradation through vegetation regeneration in the semiarid highland areas of northern Ethiopia. In order to assess the effect of exclosures on water flows, the water balance components for different vegetation regeneration stages were assessed through field measurements and modelling. Successful model calibration and validation was done based on soil water content measurements conducted during 2 years in 22 experimental plots. In the protected areas, vegetation regeneration leads to an increase in infiltration and transpiration and a more productive use of water for biomass production. In areas where additional lateral water (runon) infiltrates, source–sink systems are created. Here, up to 30% of the annual rainfall percolates through the root-zone towards the groundwater table. Increased biomass production in exclosures leads to possibilities for wood harvesting and cut and carry of grasses for livestock feeding. Together with water conservation and more productive use of water, the latter contributes to increased livestock water productivity. At the landscape scale, the creation of vegetation filters, capturing resources like water and nutrients, reinforces the rehabilitation process and healthy landscape functioning.
(Location: IWMI HQ Call no: e-copy only Record No: H042534)
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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).
6 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]
(Location: IWMI HQ Call no: e-copy only Record No: H042876)
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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.
(Location: IWMI HQ Call no: e-copy only Record No: H049344)
(0.81 MB)
Field experiments were conducted (December 2014 to May 2015) in a small irrigation scheme (60 ha) to study the effect of flood irrigation on anisotropic soils with shallow groundwater in the Lake Tana floodplains of Ethiopia. Irrigation (470 ± 33 mm) was measured using V-notches; rainfall did not occur, and the groundwater table was monitored daily using piezometers to estimate recharge from irrigated onion fields using the groundwater table fluctuation method. Recharge was influenced by applied irrigation amount, groundwater table depth, seasonal temperature variations, irrigation application efficiency and crop growth stages. The decreased deep percolation during the hottest periods and peak growth stages negatively influenced the reduction in groundwater decline caused by irrigation. The soil anisotropy also played a major role in the recharge amount: despite clay dominance in the topsoils, rapid groundwater table rises (0.02–0.56 m) were due to the presence of granular and blocky structures. Recharge was also influenced by irrigation efficiency, indicating higher recharge during periods of lower efficiency. The seasonal recharge was 34–46% of applied irrigation and there is much room for improving irrigation efficiency which is only 46 (±12) to 51 (±17)%.
8 Zewdie, M. C.; Van Passel, S.; Moretti, M.; Annys, S.; Tenessa, D. B.; Ayele, Z. A.; Tsegaye, E. A.; Cools, J.; Minale, A. S.; Nyssen, J.. 2020. Pathways how irrigation water affects crop revenue of smallholder farmers in northwest Ethiopia: a mixed approach. Agricultural Water Management, 233:106101. [doi: https://doi.org/10.1016/j.agwat.2020.106101]
(Location: IWMI HQ Call no: e-copy only Record No: H049670)
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The relationship between irrigation water availability and crop revenue is multifaceted. However, most of the previous studies focused only on the direct effect of irrigation water on crop revenue or considered that the indirect effect passes only through the farmers’ improved farm inputs usage. Nevertheless, unlike previous studies, this study argues that a one-sided argument that irrigation water directly causes high crop revenue or indirectly affects crop revenue only via the farmers’ improved farm inputs usage is incomplete, as irrigation water not only directly contributes to crop revenue but also indirectly conduces to crop revenue via both the type of crops produced and the farmers’ improved farm inputs usage. Considering the previous studies’ limitations, this study investigates pathways how small-scale irrigation water affects crop revenue and identifies challenges of small-scale irrigation farming in Fogera district, Ethiopia. Results endorsed that irrigation water has both direct and indirect effects on crop revenue. The indirect effect is 67 percent of the total effect and it is mediated by both the type of crops produced and farmers’ improved farm inputs usage. The result also indicated that irrigation user farmers have a higher income, more livestock assets and resources and better food, housing, and cloths than the non-users. Moreover, challenges related to agricultural output and input market were identified as the most severe problem followed by crop disease. The findings of our study suggest that to utilize the benefits of irrigation water properly, it is crucial to encourage farmers to use more improved farm inputs and to shift from staple to cash crop production. Moreover, farmers are frequently exposed to cheating by illegal brokers in the output market, therefore it is also important to increase farmers’ accessibility to output and input markets, the quality of improved farm inputs, and the bargaining power of farmers with market information.
9 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]
(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.
(Location: IWMI HQ Call no: e-copy only Record No: H049983)
(9.58 MB)
Based on extensive field information, farmer-led small-scale irrigation systems along the dam-regulated Tekeze River is investigated and the likelihood of future irrigation expansion within the area with modelled potential is discussed, considering facilitating and hampering factors. Due to dam-induced hydrologic alterations, downstream socio-ecological systems have strongly transformed as the irrigated area has quadrupled and the post-dam potential for perennial crop cultivation has attracted numerous migrant investors to the area, inducing inequalities but also providing opportunities. Future dam construction should involve tailored policy interventions to facilitate irrigation expansion, while safeguarding equal and sustainable access to water and land.
(Location: IWMI HQ Call no: e-copy only Record No: H050148)
(5.94 MB)
Understanding irrigation expansion and its implications on water availability is critical for development of decision support tools for sustainable water resources planning. Irrigation expansion in the Lake Tana Basin of Ethiopia from 1986 to 2016 was examined using image classification from thematic maps and remote sensing imagery (Landsat5-8 TM/ETM+, OLI). The soil-adjusted vegetation index (SAVI) imagery was used to identify irrigated cropland based on greenness. Irrigation water consumption was determined by calculating irrigation water requirements of the major crops grown with irrigation and using the estimated irrigated land size of the basin. Irrigated croplands have increased in area from 55 to 65 % in the last past 30 years (from 1986 to 2016). The classification obtained is accurate to the level of 89.6% and Kappa coefficient of 0.83. The Landsat imagery is useful in tracking of the spatiotemporal patterns of irrigated croplands for water management purposes, especially in data deficient areas dotted sparsely by small holder irrigated farms. The results indicated that irrigation consumption in the basin increased from 0.380 km3 year-1 in 1986 to 0.798 km3 year-1 in 2016. It is found that the available water cannot sustain the projected irrigation expansion unless alternative water sources are found. Also, more precise irrigation technologies have to be implemented to minimize water losses.
(Location: IWMI HQ Call no: e-copy only Record No: H050402)
(7.40 MB) (7.40 MB)
Study Region: We investigate the event runoff response in six sub-catchments in the Lake Tana sub-basin, headwater of the Blue Nile basin, northwest Ethiopia. Steep and mountainous terrains surround floodplains, imposing runoff and soil erosion in the upper catchments and flooding and sedimentation at floodplains. This study was conducted in the upland runoff source catchments.
Study Focus: The focus is to investigate catchment characteristics that control the event runoff response in upland catchments, and how recent land management practices may have contributed to improved hydrological conditions. Event rainfall and runoff data were obtained at five-minute time steps through automated divers and tipping bucket rain gauges and related to catchment characteristics.
New Hydrological Insights for the Region: Our results show that the catchment event quickflow response was controlled by different factors of both natural and anthropogenic nature of which forest and shrubs, bund density and soil organic matter content were found to be the most important to reduce event quickflow. On the contrary, increase in cropland area caused an increase in quickflow. Through least square fitting procedure of the Natural Resources Conservation Service Curve Number method (NRCS-CN), a site specific abstraction ratio ( ) value of 0.01, rather than the commonly used 0.2 or 0.05, was found to be most appropriate for the sub-humid highlands of Ethiopia.
13 Tewabe, D.; Dessie, M.; Asmamaw, D. K.; Tamiru, E.; Adgo, E.; Nyssen, J.; Walraevens, K.; Cornelis, W. M. 2021. Comparative analysis of groundwater conditions on rain-fed and irrigated agriculture in the Upper Blue Nile Basin, Ethiopia. Journal of Hydrology: Regional Studies, 37:100916. [doi: https://doi.org/10.1016/j.ejrh.2021.100916]
(Location: IWMI HQ Call no: e-copy only Record No: H050748)
(4.82 MB) (4.82 MB)
Study region: Upper Blue Nile Basin, Ethiopia.
Study focus: This study was conducted at the Koga Irrigation Scheme in the upper Blue Nile basin (Ethiopia) to investigate the influence of irrigation activity on the groundwater system. Representative samples of six shallow wells in the irrigated fields and four shallow wells in the adjacent non-irrigated (rain-fed agricultural lands) were selected. Dipmeter and hand GPS (GARMIN 60) were used for the monitoring of water table depth and fixing the location of the wells respectively. Arc GIS 10.5 has been applied for interpolation of water table depth (WTD). Water samples were collected and analyzed in the laboratory following international standards.
New hydrological insights for the region: The result shows that irrigation contributed to the water table rises of wells located in the irrigated fields which range from 0.77 m to 0.52 m and water table drops were observed in wells located in the non-irrigated fields. Investigations on the groundwater quality (GWQ) indicated that no significant effect was observed in the irrigated and non-irrigated fields. The study shows that good irrigation water management, continuous follow-up of the groundwater table and its physico-chemical properties are essential for the sustainability of the Koga Irrigation Scheme.
(Location: IWMI HQ Call no: e-copy only Record No: H052906)
(3.62 MB) (3.62 MB)
The war in Tigray, Ethiopia has triggered a massive humanitarian crisis, displacing millions. Yet, the impact on cultivated land and local food production remains poorly understood, impeding effective aid. Leveraging Sentinel-2 satellite imagery and a decision tree algorithm with Normalized Difference Vegetation Index (NDVI) time series, we developed a model to map well-cultivated cropland, defined as fields judged by field surveyors to have satisfactory to optimal crop condition in 2021–2022 field observations. Assessing satellite estimated well-cultivated land in highland croplands (
1200 m a.s.l), we found a net loss of 543 sq. km (95% CI: 81 sq. km) well-cultivated land in highland croplands equivalent to ˜ 8% of the average total surveyed cropland estimate from Central Statistical Agency between 2015 and 2019 (ESS, 2023a) in potential highland cropland. The net loss was positively associated with the density of recorded conflict incidents and sub-regions with high numbers of internally displaced persons (IDPs), consistent with a causal effect of the conflict on cultivated land.
Employing a two-way fixed effect model causal analysis with rainfall covariates, we quantified the impact of conflict incidents on cultivated land during the pre-war (2019/20) and in-war (2021) periods. Results indicated a ˜ 6.17 sq. km (SE: 2.06) additional loss per unit increase in conflict incidents during the growing season (June to October), eight times higher than total incidents occurring throughout the entire study period. We estimated the kilocalories lost due to loss of well-cultivated croplands in 2021 could have supported at least 90% of all recorded IDPs in Tigray as of June 2021, discounting for Western Tigray. Our study showcases the utility of satellite data, coupled with local agricultural knowledge, for timely and cost-effective information crucial for aid agencies and long-term rehabilitation initiatives in smallholder farming contexts.
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