Estifanos Lemma

Introduction: Evaluation of water availability and land suitability for surface irrigation practice is crucial for a country like Ethiopia whose livelihood is highly dependent on seasonal rainfed agriculture, which is susceptible to climate change and has a large population suffering from food insecurity.Methods: In this study, several factors, such as slope, land use land cover, rainfall, proximities to (market centers, roads, and rivers), and soil factors (i.e., pH, organic carbon, cation exchange capacity, electrical conductivity, available water storage capacity, drainage, depth, texture, and soil type) were considered. The data were entered and analyzed using the GIS tool and multicriteria analysis of the Analytical Hierarchy Process (AHP) to determine the suitable area for surface irrigation in the Chacha Watershed. Subsequently, a CROPWAT tool was used to check the water requirement of the dominant crops grown in the study watershed, while a flow duration curve of 90-percenti...

Background Drought is a recurrent phenomenon emerging from an inter-annual and intra-seasonal deficit of water across the atmosphere-to-aquifer continuum and these events are reported to be very severe in regions of Ethiopia. Availability of accurate precipitation observations significantly impacts the drought monitoring systems. These observations are scarce and sparsely distributed in countries like Ethiopia. To overcome such a problem, the use of satellite rainfall estimates with continuous and timely data at different spatio-temporal scales is opportune, provided their accuracy is well known. Among the currently available satellite rainfall products studies specifically in Ethiopia shown that Climate Hazard Group Infrared Precipitation with Station version 2 daily rainfall product (hereafter CHIRPSv2) has better performance and recommended as a valuable substitute for gauge rainfall data. Therefore, the current study focused on assessing the applicability of CHIRPSv2 for meteorological drought monitoring in Ethiopia. Due to the wide spatio-temporal variability of Ethiopia's climate, the performance of CHIRPSv2 rainfall product for meteorological drought monitoring has been assessed in selected river basins (Awash, Blue Nile, Baro, Danakil, Omo and Tekeze) of Ethiopia. For drought estimations, two well-known meteorological drought indices such as Effective Drought Index (EDI) and the Standardized Precipitation Index (SPI) have been utilized. Result The obtained results show that the CHIRPSv2 based EDI and SPI are able to identify all the historical drought events reported between 1982 and 2016 (such as 1984, 1992, 2003, 2009, 2011, 2012, and 2015). The time series plots of EDI and SPI values show that most of the drought events in the selected river basins occurred during their corresponding main and smaller rainy months. Detailed spatio-temporal investigations of the two worst drought years (1984 and 2011) and one drought-free year (2007) show that both the EDI and SPI could enable to identify the drought and drought-free areas correctly when compared with the available recorded historical droughts (RHD) across each river basin. Similarly, the temporal trends of EDI and SPI identified drought shows that frequency and severity of drought were higher during 1980s and 2000s than 1990s. Conclusions Such good agreement between the identified drought and historical drought indicates that CHIRPSv2 is a promising rainfall dataset, which could be used to develop drought monitoring and early warning system across different river basins of Ethiopia. Besides, the study helps to provide useful information for decision makers to implement different adaptation and mitigation measures of drought in the study area. The finding also will support to improve the existing drought monitoring and early warning system and to build resilience to drought at the river basin level.

Soil erosion is one of the most severe forms of land degradation, which has a wide range of adverse on-site and off-site impacts in the highlands of Ethiopia in general and in the study area in particular. The objective of this study was to estimate soil erosion, identify and prioritize erosion hotspot microwatersheds in Antsokia-Gemiza district. The Revised Universal Soil Loss Equation (RUSLE) was used to estimate the potential annual soil loss. Geographic Information System (GIS) and remote sensing techniques were used to delineate the microwatersheds, produce the spatial map of all parameters and outputs, and prioritize microwatersheds. Based on the analysis, the potential soil loss of the district ranges from 0 to 240 t·ha−1year−1 with a mean annual soil loss of 43.21 t·ha−1year−1. About 12442.86 ha (33.18%) of the district falls under low and moderate severity classes, and it has a total soil loss not exceeding 11 t·ha−1year−1 (which is an acceptable or tolerable range of soil ...

Continuous availability of a variety of satellite and reanalysis rainfall products have triggered the use of such products as an alternate source of rainfall data in sparsely gauge networked areas. However, before utilizing them a detailed validation of these datasets are essential to have some level of guarantee. In many parts of Africa in general and most parts of Ethiopia particularly in the lowland areas, gauge stations are very sparse and unevenly distributed. In addition, due to the nature of complex topography and geographical location, Ethiopian rainfall shows high variability both temporally and spatially. In view of the above, the present study is aimed at statistically evaluating such rainfall products across different rainfall regimes (regions with different rainfall characteristics as defined by National Meteorological Agency (NMA) of Ethiopia). In the current study, five satellite and two reanalysis rainfall products such as African Rainfall Climatology version 2 (ARC2), Tropical Applications of Meteorology using SATellite and ground-based observations (TAMSAT), Tropical Rainfall Measuring Mission-3B43 version 7 (TRMM 3B43v7), Climate Prediction Center Morphing Technique (CMORPH), Climate Hazards Group Infrared Precipitation with Stations version 2 (CHIRPSv2), the Climate Forecast System Reanalysis (CFSR) and the European Center for Medium Range Weather Forecast Reanalysis (ERA-Interim) are considered based on their spatial coverage, spatial resolution, temporal resolution, latency period and length of data records. Evaluation is done at monthly and seasonal time scales against the observed gauge rainfall data provided by the National Meteorological Agency of Ethiopia across entire Ethiopia in two different manners, first by considering the entire country as one homogeneous unit and secondly in a distributed manner across the three rainfall regimes of Ethiopia. The obtained results show that: (i) CHIRPSv2 and TRMM 3B43v7 show better performance during June to September (the main rainfall season) and during February to May (the smaller rainfall season) in regimes 1 and 2. (ii) In regime 3 these products show good performance from October to November (smaller rainy season of this regime) and March to May (main rainy season of this regime); (iii).CMORPH, TAMSAT and ARC2 show moderate performance in all three regimes; (iv) CFSR and ERA-Interim exhibit poor performance in all rainfall regimes. Overall, the detailed analysis of statistical evaluation results of the rainfall products at monthly timescale shows that CHIRPSv2 performs comparatively better than the other tested rainfall products across all rainfall regimes. However, the best performance of CHIRPSv2 is obtained in regime 2 followed by regime 1 and regime 3.