Your search found 8 records
1 Ayana, E. K.. 2007. Validation of radar altimetry lake level data and it's application in water resource management. MSc thesis. Enschede, Netherlands: International Institute for Geo-information Science and Earth Observation (ITC). 76p.
Water management ; International waters ; Radar satellite ; Measuring instruments ; Remote sensing ; Lakes ; Data analysis ; Statistical methods ; Cartography ; Satellite imagery / Ethiopia / Lake Tana / Nile River Basin
(Location: IWMI HQ Call no: 333.91 G000 AYA Record No: H043878)
(2.20 MB) (2.198MB)
2 Engda, T. A.; Bayabil, H. K.; Legesse, E. S.; Ayana, E. K.; Tilahun, S. A.; Collick, A. S.; Easton, Z. M.; Rimmer, A.; Awulachew, Seleshi Bekele; Steenhuis, T. S. 2011. Watershed hydrology of the (semi) humid Ethiopian highlands. In Melesse, A. M. (Ed.). Nile River Basin: hydrology, climate and water use. Dordrecht, Netherlands: Springer. pp.145-162.
Watersheds ; Hydrology ; Highlands ; Rainfall-runoff relationships ; Water table ; Simulation models / Ethiopia
(Location: IWMI HQ Call no: 551.483 G136 MEL Record No: H044027)
(0.35 MB)
3 Ayana, E. K.; Awulachew, Seleshi Bekele. 2008. Comparison of irrigation performance based on management and cropping types. In Awulachew, Seleshi Bekele; Loulseged, Makonnen; Yilma, Aster Denekew (Comps.). Impact of irrigation on poverty and environment in Ethiopia: draft proceedings of the symposium and exhibition, Addis Ababa, Ethiopia, 27-29 November 2007. Colombo, Sri Lanka: International Water Management Institute (IWMI). pp.14-26.
Irrigation schemes ; Performance evaluation ; Performance indexes ; Water delivery ; Crop production ; Sugarcane ; Cotton ; Tobacco ; Water productivity / Ethiopia
(Location: IWMI HQ Call no: e-copy only Record No: H044064)
(0.12 MB)
Although performance evaluation of irrigated agriculture has gained momentum since late 1980s worldwide such attempt is rarely carried out in Ethiopia. The aim of this study was to assess the performance of 7 irrigation schemes some of which are expected to contribute much to the national economy. Sugar cane is grown by three of these schemes whereas cotton is grown by three schemes and the remaining single scheme grows tobacco. With regards to management types both government agency and community managed schemes are considered. The scheme level values of water supply performance indicators show that there was no constraint of water availability and supply at scheme level. In general, schemes that grow sugar cane were found to have attained higher outputs per units of land and water used which ranges from 7794 – 10834US$/ha and 0.24 – 0.55 US$/m3 respectively. On the other hand, whether state farm or community managed, schemes that grow cotton have shown low output per units of land and water, i.e. 310 – 385 US$/ha and 0.01 – 0.05 US$/m3 respectively. Large productivity performance differences have been observed between irrigation schemes with same cropping and management types. From scheme level performance values it is not simple to identify the area where and what is going wrong which is responsible for low performance. Generally, problems casing low productivity derive both in management and deterioration of physical structures. Hence investment on improvements of physical structures, management and operation of the system at all levels will bring substantial improvement in the performances of cotton producing schemes.
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 Dagnew, D. C.; Guzman, C. D.; Zegeye, A. D.; Akal, A. T.; Moges, M. A.; Tebebu, T. Y.; Mekuria, Wolde; Ayana, E. K.; Tilahun, S. A.; Steenhuis, T. S. 2017. Sediment loss patterns in the sub-humid Ethiopian Highlands. Land Degradation and Development, 28(6):1795-1805. [doi: https://doi.org/10.1002/ldr.2643]
Sediment ; Erosion ; Gully erosion ; Humid zones ; Highlands ; Watersheds ; Catchment areas ; Rainfall-runoff relationships ; Infiltration ; Precipitation / Ethiopia / Debre Mawi Catchment
(Location: IWMI HQ Call no: e-copy only Record No: H047878)
Controlling soil erosion is important for maintaining land productivity and reducing sedimentation of reservoirs in the Ethiopian highlands. To gain insights on sediment loss patterns, magnitude of peak sediment events, and their contribution to annual loads, hydrometric and sediment concentration data were collected for five years (2010 – 2014) from the 95 ha Debre Mawi and four nested catchments (located 30 km south of Lake Tana). Soil and water conservation practices (SWCPs) consisting of soil bunds with 50 cm deep furrows were implemented in the third year, which made it possible to examine the effects of SWCPs on peak sediment loads. The results show that a 10-minute event causes soil loss of up to 11.4 Mg ha-1, which is 22% of the annual sediment yield. Thirty to seventy-five percent (up to 30 Mg ha-1day-1) of the sediment yield was contributed by the greatest daily flow in each year. The contribution increases to 86% for the two largest daily flows. SWCP interventions reduced sediment loss by half but did not affect the relative contribution of peak events to annual loads. Due to gully erosion, peak sediment loads at the outlet of the entire catchment were greater (up to 30 Mg ha-1day-1) as compared to the nested catchments without gullies (0.5 to 8 Mg ha-1day-1). Consequently, to reduce sediment loss, conservation measures should be designed to decrease runoff during large storms. This can be attained by deepening furrows on unsaturated hillsides and reducing the entrainment of unconsolidated sediment from failed gully banks.
6 Dile, Y. T.; Tekleab, S.; Ayana, E. K.; Gebrehiwot, S. G.; Worqlul, A. W.; Bayabil, H. K.; Yimam, Y. T.; Tilahun, S. A.; Daggupati, P.; Karlberg, L.; Srinivasan, R. 2018. Advances in water resources research in the Upper Blue Nile Basin and the way forward: a review. Journal of Hydrology, 560:407-423. [doi: https://doi.org/10.1016/j.jhydrol.2018.03.042]
Water resources ; Research ; Water conservation ; Soil conservation ; Erosion ; Climate change ; Land use ; Catchment areas ; Water balance ; Hydrology ; Models ; Economic development ; Agriculture ; Remote sensing / Ethiopia / Upper Blue Nile Basin
(Location: IWMI HQ Call no: e-copy only Record No: H048798)
https://www.sciencedirect.com/science/article/pii/S0022169418302087/pdfft?md5=fd653f0a22b3bbc8ecfa4c346eb5cfc9&pid=1-s2.0-S0022169418302087-main.pdf
https://vlibrary.iwmi.org/pdf/H048798.pdf
https://vlibrary.iwmi.org/pdf/H048798.pdf
(1.32 MB) (1.32 MB)
The Upper Blue Nile basin is considered as the lifeline for ~250 million people and contributes ~50 Gm3 / year of water to the Nile River. Poor land management practices in the Ethiopian highlands have caused a significant amount of soil erosion, thereby threatening the productivity of the Ethiopian agricultural system, degrading the health of the aquatic ecosystem, and shortening the life of downstream reservoirs. The Upper Blue Nile basin, because of limited research and availability of data, has been considered as the "great unknown." In the recent past, however, more research has been published. Nonetheless, there is no state-of-the-art review that presents research achievements, gaps and future directions. Hence, this paper aims to bridge this gap by reviewing the advances in water resources research in the basin while highlighting research needs and future directions. We report that there have been several research projects that try to understand the biogeochemical processes by collecting information on runoff, groundwater recharge, sediment transport, and tracers. Different types of hydrological models have been applied. Most of the earlier research used simple conceptual and statistical approaches for trend analysis and water balance estimations, mainly using rainfall and evapotranspiration data. More recent research has been using advanced semi-physically/physically based distributed hydrological models using high-resolution temporal and spatial data for diverse applications. We identified several research gaps and provided recommendations to address them. While we have witnessed advances in water resources research in the basin, we also foresee opportunities for further advancement. Incorporating the research findings into policy and practice will significantly benefit the development and transformation agenda of the Ethiopian government.
7 Moges, M. A.; Schmitter, Petra; Tilahun, S. A.; Ayana, E. K.; Ketema, A. A.; Nigussie, T. E.; Steenhuis, T. S. 2017. Water Quality Assessment by Measuring and Using Landsat 7 ETM+ Images for the Current and Previous Trend Perspective: Lake Tana Ethiopia. Water Research, 9:1564-1585. [doi: https://doi.org/10.4236/jwarp.2017.912099]
Water quality ; Assessment ; Landsat ; Deltas ; Lakes ; Sediment ; Nutrients ; Watersheds ; Water conservation ; Soil conservation ; River basins ; Phosphorus ; Remote sensing / Ethiopia / Lake Tana
(Location: IWMI HQ Call no: e-copy only Record No: H048966)
https://www.scirp.org/journal/PaperDownload.aspx?paperID=80775
https://vlibrary.iwmi.org/pdf/H048966.pdf
https://vlibrary.iwmi.org/pdf/H048966.pdf
(3.89 MB)
Recently there are signs of water quality impairment in Lake Tana, the largest fresh water in Ethiopia. The lake is the growth corridor of the government and supports millions of livelihood around. In order to sustain the benefit and maintain the ecosystem of the lake, the lake health has to be kept safe. Therefore monitoring and evaluation of the water quality of lake is very vital. This study focuses on current and previous trends water quality of the lake through measurements and Landsat Images near entry of Gumera River. Statistical analysis of the physical (Turbidity and STD and biological (Cha-a,) and chemical (DPC) water quality parameters were done. Linear and non-linear regression models between water quality parameter and reflectance of Landsat 7 ETM+ images were fitted based on band combinations. Pervious trend in turbidity was analyzed based on the regression models. The results showed that reflectance and turbidity satisfactorily result with an R2 ranging from 0.61 - 0.68. Form 1999-2014 the turbidity of the lake has indicated an increasing trend. Delta development near the entry of Gumera River has been enlarged by 48% because of an increase sediment inflow. The sign in the decreasing water quality of the lake was attributed to the non-point source sediment and nutrient inflow to the lake with high erosion rate from the watersheds. Measures to reduce the non-point source sediment and nutrient inflow by targeting the source areas (hot spots) in the agricultural watersheds need to be priority for stakeholders working on the soil and water conservation. Moreover, reducing the recession agriculture around the lake and wetland management could be crucial for improving lake water quality.
8 Dile, Y. T.; Ayana, E. K.; Worqlul, A. W.; Xie, H.; Srinivasan, R.; Lefore, N.; You, L.; Clarke, N. 2020. Evaluating satellite-based evapotranspiration estimates for hydrological applications in data-scarce regions: a case in Ethiopia. Science of the Total Environment, 743:140702. [doi: https://doi.org/10.1016/j.scitotenv.2020.140702]
Evapotranspiration ; Hydrology ; Agricultural landscape ; Satellite observation ; Remote sensing ; Water management ; Sustainability ; River basins ; Stream flow ; Land management ; Land use ; Soil moisture ; Grasslands ; Models ; Uncertainty ; Forests / Ethiopia
(Location: IWMI HQ Call no: e-copy only Record No: H049976)
https://www.sciencedirect.com/science/article/pii/S0048969720342248/pdfft?md5=33436fc788bb7601053c74729cab3e05&pid=1-s2.0-S0048969720342248-main.pdf
https://vlibrary.iwmi.org/pdf/H049976.pdf
https://vlibrary.iwmi.org/pdf/H049976.pdf
(11.60 MB) (11.6 MB)
Water resource development opens up opportunities for improving smallholder farmer livelihoods in sub-Saharan Africa; however, implementation of water resource interventions to ensure sustainability hinges on the availability of sufficient quantity and quality data for monitoring, analysis and planning. Such data is often acquired through instrumentation of water resources (e.g. stream flow monitoring) or the use of hydrological models. In sub-Saharan Africa, data scarcity has limited the ability to monitor and make appropriate decisions for water resource allocation and use. Data derived from remote sensing has been considered a viable option to fill this gap; however, there is limited research in the region that evaluate the quality of the remotely sensed based datasets. This study evaluated actual evapotranspiration (AET) estimates derived from Advanced Very High Resolution Radiometer (AVHRR AET) images and Moderate Resolution Imaging Spectrometer (MOD16 AET) images using estimates from a grid-based Soil and Water Assessment Tool (SWAT). The SWAT model was set up for the entire country of Ethiopia, and calibrated and validated using observed streamflow at several meso-scale watersheds in which satisfactory model performance was obtained. AET estimates from the calibrated and validated SWAT model were then used to evaluate remotely sensed based AET for three landscapes. The AVHRR AET better agreed with the SWAT-simulated AET than the MOD16 AET, although the AVHRR AET overestimated the SWAT-simulated AET in all of the landscapes. Both remotely sensed AET products showed better agreement with the SWAT-simulated AET over agriculture dominated landscapes compared to grassland and forest dominated landscapes. The findings of the study suggest that remotely sensed based AET may help to fine-tune hydrological models in agricultural landscapes in data-scarce regions to improve studies on the impacts of water management interventions aiming to ensure environmental sustainability while enhancing agricultural production, and household income and nutrition.
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