Your search found 4 records
1 Nicol, Alan; Langan, Simon; Victor, M.; Gonsalves, J. (Eds.) 2015. Water-smart agriculture in East Africa. Colombo, Sri Lanka: International Water Management Institute (IWMI). CGIAR Research Program on Water, Land and Ecosystems (WLE); Kampala, Uganda: Global Water Initiative East Africa (GWI EA). 352p. [doi: https://doi.org/10.5337/2015.203]
Agriculture ; Water productivity ; Small scale farming ; Irrigation schemes ; Drip irrigation ; Vegetable growing ; Climate change ; Adaptation ; Food security ; Drought tolerance ; Crops ; Sorghum ; Rice ; Maize ; Livestock production ; Land management ; Watershed management ; Rain ; Water harvesting ; Water conservation ; Water use ; Water storage ; Groundwater ; Rehabilitation ; Soil conservation ; Participatory approaches ; Highlands ; Erosion ; Sustainable development ; Arid lands ; Catchment areas ; Wetlands ; Income ; Incentives ; Smallholders ; Dams ; Gender ; Natural resources management ; Learning ; Collective action ; Case studies / Africa / Tanzania / Ethiopia / Africa South of Sahara / Uganda / Horn of Africa / Manyoni / Singida / Agago / Otuke / Nile River Basin / Birr Watershed / Debre Mawi Watershed
(Location: IWMI HQ Call no: IWMI Record No: H046950)
(8 MB)
2 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.
3 Alemie, T. C.; Tilahun, S. A.; Ochoa-Tocachi, B. F.; Schmitter, Petra; Buytaert, W.; Parlange, J.-Y.; Steenhuis, T. S. 2019. Predicting shallow groundwater tables for sloping highland aquifers. Water Resources Research, 55(12):11088-11100. [doi: https://doi.org/10.1029/2019WR025050]
Groundwater table ; Forecasting ; Highlands ; Aquifers ; Groundwater recharge ; Watersheds ; Water levels ; Wells ; Rain ; Evaporation ; Models ; Monitoring ; Soils / Ethiopia / Debre Mawi Watershed
(Location: IWMI HQ Call no: e-copy only Record No: H049497)
https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2019WR025050
https://vlibrary.iwmi.org/pdf/H049497.pdf
https://vlibrary.iwmi.org/pdf/H049497.pdf
(8.39 MB) (8.39 MB)
While hydrological science has made great strides forward during the last 50 years with the advance of computing power and availability of satellite images, much is unknown about the sustainable development of water for irrigation, domestic use, and livestock consumption for millions of households in the developing world. Specifically, quantification of shallow underground water resources for irrigation in highland regions remains challenging. The objective is to better understand the hydrology of highland watersheds with sloping hillside aquifers. Therefore, we present a subsurface flow model for hillside aquifers with recharge that varied from day to day. Recharge to the aquifer was estimated by the Thornthwaite Mather procedure. A characteristic time was identified for travel time of water flowing from the upper part of the hillside to the river or well. Using the method of characteristics, we found that the height of shallow groundwater level can be predicted by determining the total recharge over the characteristic time divided by drainable porosity. We apply the model to farmer-dug wells in the Ethiopian highlands using observed rainfall, potential evaporation, and a fitted travel time. We find that the model performs well with maximum water table heights being determined by the soil surface and minimum heights by the presence or absence of volcanic dikes downhill. Our application shows that unless the water is ponded behind a natural or artificial barrier, hillslope aquifers are unable to provide a continuous source of water during the long, dry season. This clearly limits any irrigation development in the highlands from shallow sloping groundwater.
4 Zegeye, A. D.; Langendoen, E. J.; Steenhuis, T. S.; Mekuria, Wolde; Tilahun, S. A. 2020. Bank stability and toe erosion model as a decision tool for gully bank stabilization in sub humid Ethiopian highlands. Ecohydrology and Hydrobiology, 20(2):301-311. [doi: https://doi.org/10.1016/j.ecohyd.2020.02.003]
Gully erosion ; Erosion control ; Models ; Soil loss ; Soil stabilization ; Subhumid zones ; Highlands ; Watersheds ; Groundwater table ; Runoff ; Vegetation / Ethiopia / Blue Nile Basin / Debre Mawi Watershed
(Location: IWMI HQ Call no: e-copy only Record No: H049936)
(2.29 MB)
Gullies that are expanding at alarming rate are responsible for the majority of soil losses in the (sub) humid highlands of Ethiopia. Few affordable and effective methods for gully erosion control are available in the highlands. The objective of the study was to develop cost-effective measures to halt gully expansion by determining stable-bank conditions under a variety of environmental situations using the Bank Stability and Toe Erosion Model (BSTEM). The study was carried out in the sub humid Debre Mawi watershed, located 30 km south of Lake Tana. Input data for the BSTEM model were collected using field surveys and soil sampling. After the BSTEM was tested on actual measured soil data, soil cohesion and internal friction angle were calibrated against observed gully bank retreat. Using the calibrated parameters, the model evaluated the stabilization of the existing gully bank under different scenarios in which groundwater table, bank angle and bank height, tension crack depth, vegetation, and toe protection were varied. Finally, the head-cut of the study gully was treated based on the model recommendation. The simulated results showed that a 5 m deep gully was stable under fully saturated conditions when the bank toe is protected, its upper surface is vegetated, and its bank angles do not exceed 45°. If the depth of the gully is less than 5 m or if its water table is deeper than 0.5 m, only regrading the gully bank to an angle of 45° can stabilize the gully. BSTEM showed to be an effective tool that can be used to evaluate gully control measures.
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