Your search found 10 records
1 Yilak, D. L.; Tilahun, S. A.; Schmitter, Petra; Nakawuka, Prossie; Enku, T.; Kassawmar, N. T.; Steenhuis, T. S. 2015. Determining the groundwater potential for agricultural use in Ethiopian Highlands [Abstract only] Paper presented at the 10th Alexander von Humboldt Conference 2015 on Water-Food-Energy River and Society in the Tropics. EGU Topical Conference Series, Addis Ababa, Ethiopia, 18-20 November 2015. 2p.
Agriculture ; Groundwater irrigation ; Groundwater recharge ; Water levels ; Water use ; Highlands ; Irrigation water ; Water levels ; Watersheds ; Sustainability ; Case studies / Ethiopia / Ethiopian Highlands / Robit-Bata watershed / Lake Tana
(Location: IWMI HQ Call no: e-copy only Record No: H047278)
(0.01 MB)
The Ethiopian government has declared the Lake Tana - Beles region to be a growth corridor and irrigation development is one of the priorities. Since the dry season river flow is limited, groundwater has the greatest potential for increasing irrigation in the near future. The main drawback is lack of information on sustainable groundwater use and specifically the ground water potential. Therefore the objective of this research is to calculate the annual groundwater recharge. The study was conducted in Robit-Bata, an experimental watershed of 911 ha, located at the south-eastern edge of Lake Tana. Farmers have excavated more than 300 hand dug wells for irrigation use from which, we used 50 wells for water table fluctuation observations for one year starting from April, 2014. Daily Precipitation was recorded for the same period. The annual recharge was estimated using the water – level fluctuation method. Specific yield was defined as the difference of porosity and field capacity of the subsurface formation. The annual average areal groundwater recharge was 640 mm/year, which is 41% of the rainfall and ranged from 50mm to 390mm per week for the various locations in the watershed. The greatest recharge amounts were found in the plains at the foot of the hills and river course areas consisting mostly weathered basalt rock. At those locations the groundwater rose steadily during the rainy monsoon phase. Smaller amount of recharge occurred both near the top of the hills with tough rock formation and in the, flat areas near to stream with sandy and clay deposits and groundwater at, shallow well depth. Our study indicates that the current use of the groundwater seems sustainable. Further research is required for optimized utilization of the limited groundwater resources for irrigation development to meet the food security of the community.
2 Addisie, M. B.; Ayele, G. K.; Gessess, A. A.; Tilahun, S. A.; Moges, M. M.; Schmitter, Petra S.; Steenhuis, T. S. 2015. Hydro-geomorphological features at gully heads in the humid northern Ethiopian Highlands, Birr Watershed. Paper presented at the 3rd International Conference on the Advancements of Science and Technology [ICAST], Bahir Dar, Ethiopia, 8-9 May 2015. 7p.
Hydrogeology ; Geomorphology ; Morphology ; Humid zones ; Highlands ; Watersheds ; Water table ; Soil properties ; Gully erosion ; Landscape ; Case studies / Ethiopia / Ethiopian Highlands / Birr Watershed
(Location: IWMI HQ Call no: e-copy only Record No: H047312)
(0.36 MB)
The study was conducted in the Birr watershed at twelve gully heads located close to each other. The survey includes measurements of morphological features, soil properties, water table elevations and catchment characteristics including erosion at each gully head. The analysis showed that gully head morphology could be explained by the role of different gully head controlling factors. The result suggested the maximum rate of head cut retreat reaches from 0 to 22.5m. There was no head retreat recorded from the arrested heads relative to unprotected heads. Compared to semiarid highlands of northern Ethiopia, the average short term head cut retreat was 12 fold greater. From the direct shear test, angle of internal friction by far greater than the slope of gully heads which are located at flat lands. The width depth ratio showed that the shallow depth heads were controlled by fluvial erosion whereas for the deep gully heads both fluvial and mass wasting due tension cracks are operating. In this study a significant power relationship established between the volume of the gully head and the length of retreat at the active gullies with V = 4.85 L1.05 (R2 = 0.91 and P= 0.042) which is different from the relation obtained from the entire gully system as a result of varies controlling factors.
3 Dagnew, D.; Guzman, C.; Zegeye, A.; Tebebu, T.; Akal, A.; Mekuria, Wolde; Ayana, E.; Tilahun, S.; Steenhuis, T. 2015. Effectiveness and sustainability of large scale soil and water conservation interventions in the sub-humid Ethiopian highlands: evidence from Debre Mawi watershed [Abstract only] Paper presented at the 10th Alexander von Humboldt Conference 2015 on Water-Food-Energy River and Society in the Tropics. EGU Topical Conference Series, Addis Ababa, Ethiopia, 18-20 November 2015. 1p.
Soil conservation ; Water conservation ; Humid climate ; Watersheds ; Highlands ; Sustainability ; Runoff ; Gully erosion ; Sediment / Ethiopia / Ethiopian Highlands / Debre Mawi Watershed
(Location: IWMI HQ Call no: e-copy only Record No: H047343)
http://meetingorganizer.copernicus.org/AvH10/AvH10-18-2.pdf
https://vlibrary.iwmi.org/pdf/H047343.pdf
https://vlibrary.iwmi.org/pdf/H047343.pdf
(0.04 MB) (39.04 KB)
Using measured runoff and sediment monitoring, the effectiveness of large scale soil and water conservation (SWC) implementations are analyzed from a five year (2010-2014) study, in the 95 ha Debre Mawi watershed and four nested sub-watersheds. Under the large scale government led SWC program, terraces with infiltration furrows were installed in 2012. The results indicate that runoff, sediment loads and sediment yields decreased significantly after the implementation of SWC practices. Sediment loads were reduced mainly because of the reduced runoff. Though sediment concentration decreased in the sub-watersheds, it decreased only marginally for the main watershed because of the entrainment of loose soil from the collapse of unstable banks of gullies. Infiltration furrows were effective in collecting runoff and suspended sediment (from rills) on the hillsides where Nitisols dominate (very deep, well-drained, permeable soils where rain water could infiltrate easily). But, on the saturated flat bottom lands and fields dominated by vertisols (that form wide-deep cracks during the dry season and swell during the rainy season), infiltration was restricted and conservation practices became conduits for carrying excess rainfall. Our continuous observations and photo monitoring of bunds on Nitisols and saturated bottomlands indicate that installing soil bunds on these areas caused the collapse of soil bunds in to the furrows. The soil from the collapsed bund is then easily washed away in a concentrated runoff and further initiated gullies in the Debre Mawi watershed. Large scale soil and water conservation interventions have short term effectiveness of reducing runoff and sediment loads. However, long term benefits can only be sustained with continuous maintenance of uphill infiltration furrows, as most ditches are filled up with sediments within two-three years. In addition, large scale soil and water conservation interventions should give priority to gully treatments, should consider local soil types and saturation dynamics to install bunds in the sub-humid Ethiopian highlands.
4 Dagnew, D. C.; Guzman, C. D.; Tebebu, T. Y.; Zegeye, A. D.; Akal, A. T.; Mekuria, Wolde M.; Ayana, E. K.; Tilahun, S. A.; Steenhuis, T. S. 2015. Contributions of peak sediment events to annual loads and the effects of best management practices on peak loads in the sub-humid Ethiopian highlands: the Debre Mawi watershed [Abstract only] In Nyssen J., Enyew A., Poesen J et al. (Eds.). International Conference on Tropical Lakes in a Changing Environment: Water, Land, Biology, Climate and Humans (TropiLakes), Bahir Dar, Ethiopia, 23-29 September 2015. Book of Abstracts. Bahir Dar, Ethiopia: Bahir Dar University. pp.94.
Sedimentation ; Watersheds ; Highlands ; Management techniques ; Soil conservation ; Water conservation ; Water erosion / Ethiopia / Ethiopian Highlands
(Location: IWMI HQ Call no: e-copy only Record No: H047344)
(0.66 MB)
Intense rainfall/runoff events produce large proportion of suspended sediment concentrations and sediment load responses. With an aim to mitigate land degradation problems in Ethiopia, soil and water conservation projects are being massively implemented. The effect of these conservation measures in reducing sediment in streams have never been quantified due to unavailability of sediment data. In a quantitative evaluation to quantify the contribution of intense event/daily sediment loads to annual sediment loads and effect of conservation measures in reducing erosion, we monitored three nested experimental sub-watersheds and a 95 ha main watershed in the sub-humid Ethiopian highlands, Debre Mawi watershed for four consecutive years. The contribution of the largest 10–minute events and peak daily sediment loads to annual sediment loads and the effect of Best Management Practices (BMPs) on peak sediment transport processes were evaluated. The contribution of the largest event loads reached up to 22% of the total annual sediment loads. The peak event sediment loads reached up to 11 t ha-1. The contribution of the largest daily sediment load events to annual loads is up to 86%. For the two largest daily sediment load events, the contribution reached up to 95%. The total sediment loads of the two largest daily sediment load events ranged from 40-68 t ha-1day-1 indicating that most of the annual sediment loads are transported with in one or two intense daily sediment load events in the (sub) humid Ethiopian highlands. Comparison of peak sediment loads before and after the implementation of BMPs indicates that conservation practices such as soil bunds, stone faced soil bunds and stone bunds substantially reduced the contribution and magnitude of peak sediment loads. The sediment trap efficiency of the BMPs can be further improved by making ditches deeper than existing practice of 50 cm depth in the Ethiopian highlands.
5 Addisie, M. B.; Ayele, G. K.; Gessess, A. A.; Tilahun, S. A.; Zegeye, A. D.; Moges, M. M. [NARS]; Schmitter, Petra; Langendoen, E. J.; Steenhuis, T. S. 2015. Hydrological and morphological factors at gully heads in the humid northern Ethiopian Highlands, Birr watershed [Abstract only] In Nyssen J., Enyew A., Poesen J et al. (Eds.). International Conference on Tropical Lakes in a Changing Environment: Water, Land, Biology, Climate and Humans (TropiLakes), Bahir Dar, Ethiopia, 23-29 September 2015. Book of Abstracts. Bahir Dar, Ethiopia: Bahir Dar University. pp.72.
Hydrological factors ; Gully erosion ; Humid climate ; Water table ; Watersheds ; Highlands ; Soils / Ethiopia / Birr Watershed / Ethiopian Highlands
(Location: IWMI HQ Call no: e-copy only Record No: H047416)
(0.10 MB)
In the Ethiopian highlands, gully erosion is severe. Although attempts to prevent gullying, it remains a challenge. Our objectives are to understand better the processes that control gully head cut retreat. The study was conducted in Birr watershed located at South West of Bahir Dar, Ethiopia. Twelve gully heads were selected and monitored from July to October, 2014. We measured gully head morphology, length of recession via pegging technique, soil analysis to determine soil shear strength, physical and chemical properties, water table elevations and catchment physical characteristics. Two active gully head cuts were arrested with stone riprap after regarding at 450. The result shows that the maximum rate of head cut retreat was between 0 to 22.5m. There was no head retreat observed from the protected heads compared with unprotected heads. The average short term head cut retreat was much greater than that observed in semiarid highlands of northern Ethiopia. The greater gulley rate of recession in the humid monsoon climate is likely caused by the water table that was above the gully bottom. In August when the soil became saturated, about 45% of head cut migration occurred. Thus the water table contributed to the slumping of gully heads and weakened the strength of the soil cohesion. The soil shear strength test result shows, angle of internal friction was by far greater than the slope of gully heads where heads are located in the periodically saturated flat lands. The width depth ratio showed that the shallow depth heads were controlled by fluvial erosion whereas for the deep gully heads both fluvial and mass wasting due to tension cracks was the main driving force. Both the water table control and protecting the head cuts of shallow gullies plays a key role in reducing the sediment contribution of gully in the humid Ethiopian highlands.
6 Zegeye, A. D.; Steenhuis, T. S.; Mekuria, Wolde; Dagnaw, D. C.; Addisse, M. B.; Tilahun, S. A.; Kasse, T. A. 2017. Effect of gully headcut treatment on sediment load and gully expansion in the sub humid Ethiopian Highlands. Environment and Ecology Research, 5(2):138-144. [doi: https://doi.org/10.13189/eer.2017.050208]
Gully erosion ; Sedimentation ; Humid zones ; Highlands ; River banks ; Lakes ; Soil conservation ; Water conservation ; Water resources ; Watershed management ; Concentrating / East Africa / Ethiopia / Ethiopian Highlands / Lake Tana
(Location: IWMI HQ Call no: e-copy only Record No: H048461)
The Ethiopian government has been implementing a land restoration program that aimed to restore degraded ecosystems and double agricultural productivity throughout the country since 2010. However, the success of the restoration program has been limited due to the lack of integrating gully erosion control measures. Consequently, many reservoirs in Ethiopia and downstream riparian countries have lost their storage capacity due to sedimentation, and studies demonstrated that gully erosion is one of the degradation hotspots within watersheds and contribute considerable proportion of the total sediment loads from a particular watershed. This study was conducted in one of large gullies in the Debre-Mawi watershed, northwestern Ethiopia to quantify the effect of gully head treatment in reducing the amount of sediment load generated from uplands and from the gully itself. We measured discharge, and sediment load and concentration in 2013 and 2014 at the upstream (inlet) and downstream ends (outlet) of the studied gully. Before the 2014 rainy phase, a gully headcut was stabilized with gabions at the bed and the gully bank was regarded to 45o. The gully head retreated 12 m in 2013 but gully head retreat was stopped following the implementation of the treatment in 2014. The total sediment load and sediment concentration at the outlet was reduced by 42% and 30% respectively, in 2014 (i.e., after treatment) when compared to 2013 (i.e., before treatment). The result of this study support that controlling the upward retreat of gully head is effective in reducing sediment load and concentration as well as upward movement and expansion of gullies. However, maintenance of gully head control measures is the key to sustain the benefits.
7 Dagnew, D. C.; Guzman, C. D.; Akale, A. T.; Tebebu, T. Y.; Zegeye, A. D.; Mekuria, Wolde; Tilahun, S. A.; Steenhuis, T. S. 2017. Effects of land use on catchment runoff and soil loss in the sub-humid Ethiopian highlands. Ecohydrology and Hydrobiology, 17:274-282. [doi: https://doi.org/10.1016/j.ecohyd.2017.07.004]
Land use ; Land management ; Catchment areas ; Runoff ; Soil properties ; Soil organic matter ; Soil disturbance ; Erosion ; Subhumid zones ; Hydrology ; Highlands ; Sedimentation ; Grasslands ; Cultivated land ; Tillage ; Watersheds / Ethiopia / Ethiopian Highlands
(Location: IWMI HQ Call no: e-copy only Record No: H048463)
Land use and management affects runoff and soil loss from a catchment. The present study investigated the effects of land use on runoff and suspended sediment concentration and yield in the northwestern Ethiopia. We selected two small catchments: cultivated land and grassland dominated catchments within the 95 ha Debre Mawi catchment. Hydrometric and sediment concentration data were collected for five years (i.e., 2010–2014). Significant (p < 0.05) differences in daily, monthly and annual runoff, as well as suspended sediment concentrations were observed between cultivated land and grassland dominated catchments. The greater runoff, suspended sediment concentration and yield in the cultivated catchment could be attributed to repeated tillage and low soil organic matter. Repeated tillage in the cultivated land lead to soil disturbance and the low organic matter lead to aggregate instability, both of which consequently increase the detachment of soil particles and transport by generated runoff. Our results support that land management practices that involve lower soil disturbance and increase ground cover on degraded highland areas such as the Ethiopian highlands could help reduce runoff and soil loss.
8 Mekuriaw, A.; Heinimann, A.; Zeleke, G.; Hurni, H. 2018. Factors influencing the adoption of physical soil and water conservation practices in the Ethiopian highlands. International Soil and Water Conservation Research, 6(1):23-30. [doi: https://doi.org/10.1016/j.iswcr.2017.12.006]
Water conservation ; Soil conservation ; Highlands ; Cultivated land ; Environmental effects ; Erosion ; Farmers attitudes ; Socioeconomic environment ; State intervention ; Political aspects ; Case studies / Ethiopia / Ethiopian highlands
(Location: IWMI HQ Call no: e-copy only Record No: H048702)
https://www.sciencedirect.com/science/article/pii/S2095633917302058/pdfft?md5=8e4f281067f8b1a7f7f6674eec60de0f&pid=1-s2.0-S2095633917302058-main.pdf
https://vlibrary.iwmi.org/pdf/H048702.pdf
https://vlibrary.iwmi.org/pdf/H048702.pdf
(0.97 MB) (996 KB)
Soil and Water Conservation (SWC) structures have been constructed on cultivated land for nearly 40 years to reduce soil loss and improve crop yields and people's livelihoods in the Ethiopian highlands. However, the success of this huge effort has been mixed, and the main constraints have not been investigated in detail. This study was undertaken to identify the factors determining the adoption of SWC structures in the Ethiopian Highlands. Case study areas were selected from high-potential and low-potential areas. Data were collected from 269 farmers using face-to-face interviews, and through focus group discussions, key informant interviews and field observations. Binary logistic regression model and descriptive statistics were used to analyze the data. The result showed that the majority (87%) of the farmers interviewed were using SWC structures. Regionally, nearly all farmers in the low-potential areas and 56% of farmers in the high-potential areas constructed and were maintaining the structures properly. This disparity is due to the fact that in the low-potential areas there have been strong governmental involvement and technical and financial support, and hence the farmers there have a better understanding of the multiple uses of physical SWC structures than do farmers in the high-potential areas. In addition, off-farm activities and free grazing plays a substantial role. We can conclude that clear understanding of the benefits of SWC structures by farmers, active involvement and technical support from the government, and genuine participation of farmers in SWC practices were found to be main factors in the adoption of SWC measures.
9 Addisie, M. B.; Langendoen, E. J.; Aynalem, D. W.; Ayele, G. K.; Tilahun, S. A.; Schmitter, Petra; Mekuria, Wolde; Moges, M. M.; Steenhuis, T. S. 2018. Assessment of practices for controlling shallow valley-bottom gullies in the sub-humid Ethiopian Highlands. Water, 10(4):1-15.
Gully erosion ; Assessment ; Best practices ; Rehabilitation ; Sediment ; Highlands ; Valleys ; Vegetation ; Slope ; Farmers ; Watersheds ; Dams ; Grasses ; Soil conservation ; Water conservation / Africa / Ethiopia / Ethiopian Highlands
(Location: IWMI HQ Call no: e-copy only Record No: H048964)
Rehabilitation of large valley bottom gullies in developing countries is hampered by high cost. Stopping head cuts at the time of initiation will prevent large gullies from forming and is affordable. However, research on practices to control shallow gully heads with local materials is limited. The objective of this research was therefore to identify cost-effective shallow gully head stabilization practices. The four-year study was conducted on 14 shallow gullies (<3 m deep) in the central Ethiopian highlands. Six gullies were used as a control. Heads in the remaining eight gullies were regraded to a 1:1 slope. Additional practices implemented were adding either riprap or vegetation or both on the regraded heads and stabilizing the gully bed downstream. Gully heads were enclosed by fencing to prohibit cattle access to the planted vegetation. The median yearly head retreat of the control gullies was 3.6 m a-1 with a maximum of 23 m a-1. Vegetative treatments without riprap prevented gully incision by trapping sediments but did not stop the upslope retreat. The gully heads protected by riprap did not erode. Regrading the slope and adding riprap was most effective in controlling gully head retreat, and with hay grown on the fenced-in areas around the practice, it was profitable for farmers.
10 Fenta, H. M.; Aynalem, D. W.; Malmquist, L.; Haileslassie, Amare; Tilahun, Seifu A.; Barron, J.; Adem, A. A.; Adimassu, Z.; Zimale, F. A.; Steenhuis, T. S. 2024. A critical analysis of soil (and water) conservation practices in the Ethiopian Highlands: implications for future research and modeling. Catena, 234:107539. [doi: https://doi.org/10.1016/j.catena.2023.107539]
Soil conservation ; Water conservation ; Highlands ; Soil loss ; Erosion ; Sediment ; Ecosystem services ; Environmental monitoring ; Land use ; Crop yield ; Modelling / Africa / Ethiopia / Ethiopian Highlands
(Location: IWMI HQ Call no: e-copy only Record No: H052323)
(8.68 MB)
Soil and water conservation have been traditionally part of farming practices for thousands of years. Despite massive efforts to implement modern soil and water conservation practices (SWCPs) in the Ethiopian Highlands, soil erosion increased after the 1970s when social and political events led to a remarkable change in land use. This review aims to critically analyze the impact of conservation practices on soil loss and crop yield and highlight research and modeling gaps. In doing so, 120 published articles on experimental and simulated soil losses in the Ethiopian Highlands were retrieved from the refereed literature. We found that most published experimental studies evaluating SWCPs lasted less than five years in areas of less than 100 ha. Most modeling studies were over short periods, too; some models simulated soil loss over large areas. The literature analysis for these short-term experimental studies showed that SWCP decreased soil loss on individual sites and increased crop yield in semi-arid regions. Simulated sediment concentration increased as a function of watershed size, while observed soil losses did not follow this trend. Moreover, the decrease in soil loss due to the soil and water conservation practices on small plots was also greatly overestimated. Consequently, past research and current modeling techniques are inconclusive on the effectiveness of SWCPs in large catchments over periods exceeding five years and those with active gullies. Additional long-term experimental studies in catchments are required to evaluate whether SWCPs can decrease sediment loads.
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