scholarly journals Hydro-Climatic Variability: A Characterisation and Trend Study of the Awash River Basin, Ethiopia

Hydrology ◽  
2019 ◽  
Vol 6 (2) ◽  
pp. 35 ◽  
Author(s):  
Mahtsente Tibebe Tadese ◽  
Lalit Kumar ◽  
Richard Koech ◽  
Birhanu Zemadim

The objective of this study was to characterize, quantify and validate the variability and trends of hydro-climatic variables in the Awash River Basin (ARB) in Ethiopia using graphical and statistical methods. The rainfall and streamflow trends and their relationships were evaluated using the regression method, Mann–Kendall (MK) test and correlation analysis. The analysis focused on rainfall and streamflow collected from 28 and 18 stations, respectively. About 85.7% and 75.3% of the rainfall stations exhibited normal to moderate variability in annual and June to September rainfall, respectively, whereas 96.43% of rainfall stations showed high variability in March to May. The MK test showed that most of the significant trends in annual rainfall were decreasing except in two stations. These research findings provide valuable information on the characteristics, variability, and trend of rainfall and streamflow necessary for the design of sustainable water management strategies and to reduce the impact of droughts and floods in the ARB.

2020 ◽  
Vol 12 (21) ◽  
pp. 9221
Author(s):  
Girma Berhe Adane ◽  
Birtukan Abebe Hirpa ◽  
Cholho Song ◽  
Woo-Kyun Lee

Understanding the timing and variability of rainfall is crucial for the effective management of water resources in river basins dominated by rainfed agricultural practices. Our study aimed to characterize rainfall and analyze the trends in the length of wet spells (LWS) in the Upper Awash River Basin—one of the most water-stressed river basins in Ethiopia. We applied statistical descriptors and a Mann–Kendall (MK) test to determine the onset, end, and LWS for the small (Belg) and main (Kiremt) rainy seasons across different landscapes of the basin. We observed highly stable rainfall onsets in all stations during both seasons. However, unlike the Kiremt season, the LWS in the Belg season was too short and unreliable for rainfed agriculture. Based on the MK test, an increasing monotonic trend in LWS during the Kiremt season was detected only in the mountainous landscape of the basin. In contrast, we observed no trends in the remaining stations in the Upper Valley region of the basin, despite the linear regressions inferring an upward or downward pattern. Our findings provide accurate climatological information for the effective development of rainwater management strategies in the Upper Awash River Basin.


2021 ◽  
Author(s):  
sejal chandel ◽  
suvarna shah

<p>In recent study, Gujarat has become one of the India’s most urbanized state, causing severe flash flooding. The Sabarmati river is one of the major west-flowing rivers in India and biggest river of north Gujarat.Urbanization should meet the population’s need by enlargement of paved areas, which has unusually changed the catchment’s hydrological and hydraulic characteristic. Therefor, the frequency of flash flooding in Sabarmati river has been increased. The Sabarmati river basin experienced eight times devastating flooding coendition between 1972 to 2020.Among which July 2017 flooding event breakdown a 112 years old record of 1905. The Dharoi dam and Wasna barrage on Sabarmati river and surrounding district Kheda, Mehsana, Gandhinagar, Ahmedabad received a huge rainfall caused anomalous inflow to tributary which forced the dam authorities to release huge discharge in short duration which leads to flooding. The Sabarmati riverfront of Ahmedabad had been going under water for five days due incessant rainfall in the city that leads to swelling of the Sabarmati river in 2017. In order to determine extent of Inundation, Hydrodynamic Model HEC-RAS(5.0.6) with Arc GIS was used. Various scenarios were run with HEC-RAS to study the impact of flow simulation on flood inundation(with & without riverfront project). The simulated flood depths have been compared with actual depths obtained at gauging station, which were collected from Government authorities. Ultimately, the analysis was used to create maps for different return periods with RAS Mapper and ArcMap that visually show the reach of the floodplains, illustrating the affected areas. Results demonstrate the usefulness of  modelling system to predict the extent of flood inundation and thus support analyses of management strategies to deal with risk associated with infrastructure in an urban setting.</p>


2006 ◽  
Vol 46 (8) ◽  
pp. 993 ◽  
Author(s):  
S. M. Robertson

The impact of different management strategies on production and profit can be evaluated with knowledge of how sheep production responds to changes in the available feed base and sheep or pasture management. This study aimed to quantify on-farm pasture and sheep production in mixed sheep and cropping systems in the Victorian Mallee of south-eastern Australia (325 ± 50 mm annual rainfall) as a prelude to computer simulation modelling. During 2001 (average rainfall) and 2002 (extreme drought) pasture production, the feed base and sheep production were monitored in 15 paddocks on 5 properties located across the region. Crop stubbles were the major source of feed for 6 months of the year, enabling ewes to maintain liveweight. There was more variation in pasture parameters between paddocks at the 1 location than between locations. The botanical composition, plant density, soil fertility and management were key variables associated with between-paddock variation in pasture production. Variation in pasture production between years was larger than within-year differences. In contrast, stocking rates were not much lower in the drought year of 2002 than in 2001. This study suggests there is potential for management to improve pasture production, and demonstrates the importance of feed sources other than annual pasture for sheep production in environments where the annual pasture growing season is short.


Atmosphere ◽  
2020 ◽  
Vol 11 (9) ◽  
pp. 883 ◽  
Author(s):  
Mahtsente Tadese ◽  
Lalit Kumar ◽  
Richard Koech

Understanding the hydrological processes of a watershed in response to climate change is vital to the establishment of sustainable environmental management strategies. This study aimed to evaluate the variability of potential evapotranspiration (PET) and water availability in the Awash River Basin (ARB) under different climate change scenarios and to relate these with long-term drought occurrences in the area. The PET and water availability of the ARB was estimated during the period of 1995–2009 and two future scenarios (2050s and 2070s). The representative concentration pathways (RCP4.5 and RCP8.5) simulations showed an increase in the monthly mean PET from March to August in the 2050s, and all the months in the 2070s. The study also identified a shortage of net water availability in the majority of the months investigated and the occurrence of mild to extreme drought in about 40–50% of the analysed years at the three study locations (Holetta, Koka Dam, and Metehara). The decrease in water availability and an increase in PET, combined with population growth, will aggravate the drought occurrence and food insecurity in the ARB. Therefore, integrated watershed management systems and rehabilitation of forests, as well as water bodies, should be addressed in the ARB to mitigate climate change and water shortage in the area.


2018 ◽  
Vol 7 (4) ◽  
pp. 2225 ◽  
Author(s):  
Rawshan Othman Alia ◽  
Zhao Chunjua ◽  
Zhou Yihona ◽  
Liu Ping ◽  
Arien Heryansyaha ◽  
...  

Research on the impact of climate change on water resources has attracted the attention of academician and policy makers. This paper tends to analyze the impact of changes in air temperature and rainfall factors on the amount of water resources in the Huai River Basin from 1980 to 2014. Air temperature and rainfall data were collected from six meteorological stations. Hydrological and water resources evaluation data were collected from the Bengbu Hydrological Station in the Huai River Basin. Research findings revealed an increasing trend of average annual air temperature, with the highest increase of 0.293oC recorded at Bengbu in Anhui Province. The western part of the study area has shown a rising rainfall while the eastern part (the middle reaches of the Huai River) witnessed a declining rainfall. The rainfall in the Huai River Basin was significantly influenced by the natural fluctuations as the average rainfall in the study area was in a vaguely declining trend. This resulted in gradual decrease in the quantity of the Basin’s water resources due to decreasing rainfall and rising air temperature. Regression and sensitivity analyses were employed to develop a mathematical model between water resources quantity and changes in air temperature and rainfall. Based on regression analysis findings, changes in rainfall have a much bigger impact on its water resources quantity than changes in its air temperature.  


2021 ◽  
Vol 57 (No. 2) ◽  
pp. 75-94
Author(s):  
Ainur Ainiah Azman Husni ◽  
Siti Izera Ismail ◽  
Noraini Jaafar ◽  
Dzarifah Zulperi

Bacterial fruit blotch (BFB) caused by Acidovorax citrulli, represents one of the most destructing diseases of cucurbits, especially to watermelon- and melon producing-regions. This disease has been spread sporadically to many countries globally, due to the unintentionally dispersal of contaminated commercial seeds. The BFB causes massive yield losses up to 100% under conducive conditions. Once infected, all parts of the host plants are extremely susceptible to this bacterium, especially the seedlings and fruits parts. In recent years, various management approaches and detection tools have been employed to control A. citrulli. Genotypic characterization methods revealed two distinct groups of A. citrulli strains; (i) group I strains primarily isolated from non-watermelon cucurbits and consist of moderate to highly aggressive strains from wide range of cucurbit hosts, and (ii) group II strains isolated from watermelon which are highly aggressive on watermelon, but mildly aggressive on non-watermelon hosts. In this paper, an attempt has been made to review research findings where the impact of diverse methods and management approaches were applied in detection and controlling of A. citrulli infection. A better understanding of this devastating bacterium will serve as guidelines for agricultural practitioners in developing the most efficient and sustainable BFB control strategies.


2016 ◽  
Vol 8 (1) ◽  
pp. 127-141 ◽  
Author(s):  
Daniel Bekele ◽  
Tena Alamirew ◽  
Asfaw Kebede ◽  
Gete Zeleke ◽  
Assefa M. Melese

The national economy and food security of many sub-Saharan countries relies on rain-fed agriculture, hence the impact of rainfall variability is highly significant. The intent of this study is to characterize rainfall variability and trend in Awash River Basin for agricultural water management using standard rainfall statistical descriptors. Long-term climate data of 12 stations were analyzed. Onset and cessation dates, length of growing period (LGP) and probability of dry spell occurrences were analysed using INSTAT Plus software. The Mann–Kendall test and the Sen's slope method were used to assess the statistical significance of the trend. The results show high variability of rainfall (38–73%), LGP (30–38 days) and high probability of dry spell occurrence (up to 100%) during the Belg season (the short rainy season from March to May) compared with the Kiremt season (the main rainy season from June to September) in all stations. Belg season showed a non-significant decline trend in most of the stations, whereas the Kiremt season indicated the contrary. The finding also revealed that supplementary irrigation is vital, especially in the Belg season to cover up to 40% of the crop water requirement deficit.


2015 ◽  
Vol 16 ◽  
pp. 77-94 ◽  
Author(s):  
Gopal D Bhatta ◽  
Pramod K Aggarwal ◽  
Amit Shrivastava

We investigate whether spatial variations in climatic resource such as rainfall have prompted livelihood diversification, local adaptation and household food availability in Indo-Gangetic Plains using data from a household survey of 2660 farm-families carried out in India, Bangladesh and Nepal. We found that on-farm livelihood sources are higher in high rainfall regime (1300-1800 mm) compared to medium (<1300 mm) and very high rainfall regime (>1800 mm). The off-farm sources are higher in medium rainfall regime. Although a large number of changes are attributed to harvest better yield, yet farmers made numbers of changes in response to climatic variability as well. Although agricultural livelihood and local adaptation are restrained by several climatic and non-climatic factors; the amount of annual rainfall significantly affects livelihood diversification, and the impact of climatic stressors becomes more pronounced when there is interaction with other non-climatic factors. The results imply that livelihood and adaptation strategies should be tailor made along the climatic and non-climatic resources.


1994 ◽  
Vol 16 (1) ◽  
pp. 77 ◽  
Author(s):  
Smith DM Stafford ◽  
A Mcnee ◽  
B Rose ◽  
G Snowdon ◽  
CR Carter

In recent years Aboriginal people have regained ownership of large areas of rangeland, and in many cases are considering pastoral enterprises in their move towards self-sufficiency. New developments in research and extension must be made accessible to them. Rangeland researchers have recognised the need to focus much more on integrating scientific results with a better social understanding of managers' goals. Recent research indicates that goals and strategies in the commercial industry are often neither optimal nor singular. This applies particularly to Aboriginal communities; these have an even broader range of land use goals relating to traditional and non-traditional elements, the latter stemming partly from the introduced pastoral industry. Past assessments of Aboriginal pastoral projects have paid scant attention to identifying Aboriginal management goals and considering how they may interact with the project or conflict with each other. Attitudes to risk and production stability have rarely been determined, and consequently the impact of climatic variability has not been adequately considered. This has lead to the imposition of inappropriate management strategies and an over-optimistic view of potential returns. Based on goals that Aboriginal communities may have, this paper shows in principle how a pastoral enterprise study could take account of climatic variability in assessing stability and risk. One major set of alternative management strategies has been modelled with RANGEPACK Herd-Econ. This highlights certain features of low stocking approaches which may be lower in risk, more stable in turn-off, and more compatible with other Aboriginal community goals. Assessment of Aboriginal pastoral projects should place more emphasis on identifying what the goals of the communities and managers really are, how these goals interact, and consequently what form of enterprise is most appropriate. Some important points for the assessment of options are suggested. Some case studies need to be undertaken to document the interaction between community aspirations and a range of enterprise types, and hence to evaluate the potential effectiveness of these approaches to assessment.


2021 ◽  
Author(s):  
Thanh Duc Dang ◽  
Jia Yi Ng ◽  
Stefano Galelli

&lt;p&gt;Southeast Asia&amp;#8217;s electricity supply largely depends on the hydropower resources of the Mekong, Chao Phraya, Irrawaddy, and Salween River Basins. Uncertain precipitation patterns, rising temperature, and other climate-driven changes are exposing these resources to unprecedented risks, prompting decision makers to re-evaluate existing reservoir management strategies through climate change risk assessments. These assessments are important in shaping the operators&amp;#8217; response to hydro-climatic variability and are necessary to ensure energy security in the region. In this study, we developed high-resolution, semi-distributed hydrological models to examine the potential changes of hydropower availability under projected future climate scenarios in the four largest river basins in South East Asia. Specifically, we relied on a novel variant of the Variable Infiltration Capacity (VIC) model that integrates reservoir operations into the routing scheme, warranting a more accurate representation of cascade reservoir systems. Climate change impacts were derived from the outputs of five Global Circulation Models (GCMs) forced by two Shared Socioeconomic Pathways (SSPs 2.6 and 8.5) emission scenarios in the Coupled Model Intercomparison Project Phase 6 (CMIP6). We find that hydropower generation would be altered significantly in all scenarios in terms of temporal variability and magnitude due to the changes in duration and magnitude of the summer monsoon. Our findings further stress the importance of exploring how the impact of climate change on hydropower availability propagates through water-energy systems and call for adaptive reservoir operation strategies.&lt;/p&gt;


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