Papers by Semu Ayalew Moges
Hydrology and Earth System Sciences, Jan 9, 2018
AGU Fall Meeting Abstracts, Dec 1, 2012
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Natural Resources, 2022
Flood is a natural process generated by the interaction of various driving factors. Flood peak fl... more Flood is a natural process generated by the interaction of various driving factors. Flood peak flows, flood frequency at different return periods, and potential driving forces are analyzed in this study. The peak flow of six gauging stations, with a catchment area ranging from 169-124,108 km 2 and sufficient observed streamflow data, was selected to develop threshold (3 rd quartile) magnitude and frequency (POTF) that occurred over ten years of records. Sixteen Potential climatic, watershed and human driving factors of floods in the study area were identified and analyzed with GIS, Pearson's correlation, and Principal Correlation Analysis (PCA) to select the most influential factors. Eight of them (MAR, DA, BE, VS, sand, forest AGR, PD) are identified as the most significant variables in the flood formation of the basin. Moreover, mean annual rainfall (MAR), drainage area (DA), and lack of forest cover are explored as the principal driving factors for flood peak discharge in Wabi-Shebele River Basin. Finally, the study resulted in regression equations that helped plan and design different infrastructure works in the basin as ungauged catchment empirical equations to compute Q MPF , Q 5 , Q 10 , Q 50 , and Q 100 using influential climate, watershed, and human driving factors. The results of these empirical equations are also statistically accepted with a high significance correlation (R 2 > 0.9).
International Journal of Energy and Water Resources, 2021
The development agenda of Ethiopia is to achieve a lower-middle-income country status by 2030. Th... more The development agenda of Ethiopia is to achieve a lower-middle-income country status by 2030. The agenda focuses on the development of the countries water, energy, and land-based resources to achieve 100% national water-energy-food security. Under such circumstances, understanding the demand and supply of resources is essential for sustainable development. This paper attempts to present the prospect of water-energy-food security of Ethiopia by 2030 and 2050 under three development scenarios: Business as Usual, Revised Vision 2030, and Agricultural Intensification Scenarios. The analysis was done using the Climate, Land, Energy and Water Systems modelling framework. The finding showed Ethiopia has adequate renewable energy and water resources to satisfy the growing demand for water supply, energy and food by 2050. The dominant hydropower energy capacity will be limited after 2040 and replaced by solar and other technologies. The target food production is constrained by limited land availability and productivity. Doubling of agricultural productivity is needed to effectively reduce the burden on land encroachment to sensitive ecosystems and reduce the dependency on imported food. It can be cautiously concluded that from resources supplyā€“demand aspects, Ethiopia achieves middle-income country status by developing its untapped water and land resources. The need for large-scale investment and human resources capacity is recognized as limitations for large-scale water and energy infrastructure development. A policy-supported investment that is focused on doubling agricultural productivity is also essential to maintain food security and ecosystem integrity of the country.
Remote Sensing, 2021
Drought is one of the least understood and complex natural hazards often characterized by a signi... more Drought is one of the least understood and complex natural hazards often characterized by a significant decrease in water availability for a prolonged period. It can be manifested in one or more forms as meteorological, agricultural, hydrological, and/or socio-economic drought. The overarching objective of this study is to demonstrate and characterize the different forms of droughts and to assess the multidimensional nature of drought in the Abbay/ Upper Blue Nile River (UBN) basin and its national and regional scale implications. In this study, multiple drought indices derived from in situ and earth observation-based hydro-climatic variables were used. The meteorological drought was characterized using the Standardized Precipitation Index (SPI) computed from the earth observation-based gridded CHIRPS (Climate Hazards Group InfraRed Precipitation with Station) rainfall data. Agricultural and hydrological droughts were characterized by using the Soil Moisture Deficit Index (SMDI) and...
Journal of Hydrology and Hydromechanics, 2021
Recently water resources reanalysis (WRR) global streamflow products are emerging from high- reso... more Recently water resources reanalysis (WRR) global streamflow products are emerging from high- resolution global models as a means to provide long and consistent global streamflow products for assessment of global challenge such as climate change. Like any other products, the newly developed global streamflow products have limitations accurately represent the dynamics of local streamflow hydrographs. There is a need to locally evaluate and apply correction factors for better representation and make use of the data. This research focuses on the evaluation and correction of the bias embedded in the global streamflow product (WRR, 0.25Ā°) developed by WaterGAP3 hydrological model in the upper Blue Nile basin part of Ethiopia. Three spatiotemporal dynamical bias correction schemes (temporal-spatial variable, temporal-spatial constant and spatial variable) tested in twelve watersheds of the basin. The temporal-spatial variable dynamical bias correction scheme significantly improves the stre...
Journal of Water Resource and Protection, 2021
Flood events vary with sub-regions, sites and time and show complex characteristics. This study i... more Flood events vary with sub-regions, sites and time and show complex characteristics. This study investigated temporal variabilities in flood discharges and relationships with principal driving factors in data scarce Wabi Shebele River Basin. The preliminary analysis using exploratory data analysis (EDA) on annual and seasonal maximum discharge reveals that there are cycles of extreme flows at five-and ten-year intervals respectively throughout the basin. The statistical verification using the Mann-Kendall test and Quantile perturbation method indicates a significant trend in flood magnitude and frequency entire the basin in the early 21st century. For longest period (1980-2010) annual maximum stream flow shows significant positive trend (p-value < 0.05) in middle catchments and negative trend (p-value < 0.05) in eastern catchments. The years: 1986-1995, 2006-2010 are the years in which positive significant anomalies occurred in all seasons, while the years: 1980-1985, 1996-2005 are the occurrence years of significant negative anomalies. Rainfall from climate drivers; DA, BE, VS and fraction of sand from environmental background drivers; fraction of forest and population density from external factors were identified as the powerful driving factors of flood variabilities in the Wabi Shebele River Basin.
ā˛¢ Citizen participation in science can: 7. IMPACT ā˛¢ Following the high school students in a longi... more ā˛¢ Citizen participation in science can: 7. IMPACT ā˛¢ Following the high school students in a longitudinal study to see the impact of their participation in the citizen science initiative and STEM activities on their future careers ā˛¢ Focus on gender studies and self-efficacy, specifically studying how high school female students perceive their participation in citizen science data collection and how they are perceived by their social network ā˛¢ Moving from data co-generation to data application to guide water management decisions in the field
Water Resources Management, 2019
The increasing availability of global observation datasets, both from in situ and remote sensors,... more The increasing availability of global observation datasets, both from in situ and remote sensors, and advancements in earth system models and data assimilation algorithms have generated a number of water resources reanalysis products that are available at global scale and high spatial and temporal resolutions. These products hold great potential for water resources applications, but their levels of uncertainty need to be evaluated at local scale. In this work, we evaluate the runoff product from two multi-model global water resources reanalyses (WRRs), available at 0.5Ā°(WRR1) and 0.25Ā°(WRR2) grid resolutions, which were produced within the framework of a European Union project (eartH2Observe) in the upper Blue Nile basin. Analysis indicates that the recently released WRR2 UniK product exhibits consistently better performance statistics than the earlier coarser-resolution WRR1 and the rest of the WRR2 products at all ranges of temporal and spatial scale evaluated. Streamflow simulations based on gauged rainfall forcing and the locally set hydrological model CREST outperforms all the other products, including UniK. Global hydrological products can be a data source for various water resources planning and management applications in data-scarce areas of Africa. This study cautions against using available global hydrological products without prior uncertainty evaluation.
Geosciences, 2018
The Upper Blue Nile (UBN) basin is less-explored in terms of drought studies as compared to other... more The Upper Blue Nile (UBN) basin is less-explored in terms of drought studies as compared to other parts of Ethiopia and lacks a basin-specific drought monitoring system.
Hydrology, 2017
The aim of this study is to assess the performance of various global precipitation products for w... more The aim of this study is to assess the performance of various global precipitation products for water resources application in the Upper Blue Nile basin, Ethiopia. Three precipitation products of gauge-adjusted (corrected) CMORPH, (TRMM) TMPA 3B42v7 and ECMWF reanalysis products are evaluated. A Coupled Routing and Excess Storage (CREST) distributed hydrological model is calibrated and used for the evaluation. The model is calibrated for 2000-2005 and validated for 2006-2011 periods using daily observed rainfall and discharge datasets. The results indicate the precipitation products consistently provide a better performance of runoff estimation when they are independently calibrated than simulation modes of the products. We conclude as long as each product is calibrated independently, global precipitation products can provide enough information for water resource management in data-scarce regions of upper Blue Nile Basin. Further analysis is underway to understand the response characteristics of the precipitation products at larger spatio-temporal scales.
Hydrology and Earth System Sciences Discussions, 2017
Prediction of seasonal precipitation can provide actionable information to guide management of va... more Prediction of seasonal precipitation can provide actionable information to guide management of various sectoral activities. For instance, it is often translated into hydrological forecasts for better water resources management. However, many studies assume homogeneity in precipitation across an entire study region, which may prove ineffective for operational and local-level decisions, particularly for locations with high spatial variability. This study proposes advancing local-level seasonal precipitation predictions by first conditioning on regional-level predictions, as defined through objective cluster analysis, for western Ethiopia. To our knowledge, this is the first study predicting seasonal precipitation at high resolution in this region, where lives and livelihoods are vulnerable to precipitation variability given the high reliance on rain-fed agriculture and limited water resources infrastructure. The combination of objective cluster analysis, spatially high-resolution pred...
Journal of Hydrometeorology, 2016
An extensive evaluation of nine global-scale high-resolution satellite-based rainfall (SBR) produ... more An extensive evaluation of nine global-scale high-resolution satellite-based rainfall (SBR) products is performed using a minimum of 6 years (within the period of 2000ā€“13) of reference rainfall data derived from rain gauge networks in nine mountainous regions across the globe. The SBR products are compared to a recently released global reanalysis dataset from the European Centre for Medium-Range Weather Forecasts (ECMWF). The study areas include the eastern Italian Alps, the Swiss Alps, the western Black Sea of Turkey, the French CĆ©vennes, the Peruvian Andes, the Colombian Andes, the Himalayas over Nepal, the Blue Nile in East Africa, Taiwan, and the U.S. Rocky Mountains. Evaluation is performed at annual, monthly, and daily time scales and 0.25Ā° spatial resolution. The SBR datasets are based on the following retrieval algorithms: Tropical Rainfall Measuring Mission Multisatellite Precipitation Analysis (TMPA), the NOAA/Climate Prediction Center morphing technique (CMORPH), Precipit...
Hydrology and Earth System Sciences, 2012
Estimation of peak flow quantiles in ungauged catchments is a challenge often faced by water prof... more Estimation of peak flow quantiles in ungauged catchments is a challenge often faced by water professionals in many parts of the world. Approaches to address such problem exist, but widely used techniques such as flood frequency regionalisation is often not subjected to performance evaluation. In this study, the jack-knifing principle is used to assess the performance of the flood frequency regionalisation in the complex and data-scarce River Nile basin by examining the error (regionalisation error) between locally and regionally estimated peak flow quantiles for different return periods (Q T). Agglomerative hierarchical clustering based algorithms were used to search for regions with similar hydrological characteristics. Hydrological data employed were from 180 gauged catchments and several physical characteristics in order to regionalise 365 identified catchments. The Generalised Extreme Value (GEV) distribution, selected using L-moment based approach, was used to construct regional growth curves from which peak flow growth factors could be derived and mapped through interpolation. Inside each region, variations in at-site flood frequency distribution were modelled by regression of the mean annual maximum peak flow (MAF) versus catchment area. The results showed that the performance of the regionalisation is heavily dependent on the historical flow record length and the similarity of the hydrological characteristics inside the regions. The flood frequency regionalisation of the River Nile basin can be improved if sufficient flow data of longer record length of at least 40 yr become available.
Hydrological Sciences Journal, 2011
A critical discussion of recent studies that analysed the effects of climate change on the water ... more A critical discussion of recent studies that analysed the effects of climate change on the water resources of the River Nile Basin (RNB) is presented. First, current water-related issues on the RNB showing the particular vulnerability to environmental changes of this large territory are described. Second, observed trends in hydrological data (such as temperature, precipitation, river discharge) as described in the recent literature are presented. Third, recent modelling exercises to quantify the effects of climate changes on the RNB are critically analysed. The many sources of uncertainty affecting the entire modelling chain, including climate modelling, spatial and temporal downscaling, hydrological modelling and impact assessment are also discussed. In particular, two contrasting issues are discussed: the need to better recognize and characterize the uncertainty of climate change impacts on the hydrology of the RNB, and the necessity to effectively support decision-makers and propose suitable adaptation strategies and measures. The principles of a code of good practice in climate change impact studies based on the explicit handling of various sources of uncertainty are outlined.
Urban Water Journal, 2013
This paper examines the long-term historical changes in frequency and amplitude of rainfall extre... more This paper examines the long-term historical changes in frequency and amplitude of rainfall extremes in two very close stations of Addis Ababa, the Addis Ababa Observatory (AAO) and Addis Ababa Bole (AAB) records including some surrounding measurements using the second half of 20th century data. The method used to examine trends and oscillatory patterns is the quantile perturbation method, especially designed for extreme conditions. The result shows that the Addis Ababa Observatory (AAO) shows an exceptionally increasing trend in its extreme events while the rest of the stations show an oscillating pattern. Exceptional behaviour at AAO is also noticed from unique global climatic indices. Both Pacific Decadal Oscillation and the Southern Oscillation Index are opposed to other stations. A possible reason for the increasing trend is linked with the growing urbanization that has been occurring in Addis Ababa city in the past decades. Nevertheless the variability of AAO rainfall extremes...
Journal of Hydrology: Regional Studies
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Papers by Semu Ayalew Moges