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Statistical Downscaling of Daily Temperature and Rainfall Data from Global Circulation Models, in Borkena River Catchment, Ethiopia
Kasye Shitu,
Shimelis Berhanu
Issue:
Volume 9, Issue 5, October 2020
Pages:
87-97
Received:
18 February 2020
Accepted:
3 March 2020
Published:
24 September 2020
Abstract: Statistical downscaling models for temperature and precipitation in Borkena River Catchment, have been developed and applied to calculate the changes in historic, current and future climate changes. Projected changes in precipitation and temperature were analyzed using the outputs from GCMs and stations data (1976-2005) which were collected from 4 observed meteorological stations (predictand) and downscaling using SDSM version 4.2.9a. The study investigated how these changes in temperature and precipitation might translate into changes in livelihoods of people and other biophysical components using impact assessments. The objective of this paper was to evaluate the statistical downscaling methods in estimating monthly average rainfall and temperature, in line with this it was also conducted to project the future climate situation of Borkena River catchment (Ethiopia). Accordingly, the results revealed that both temperatures (maximum and minimum) showed an increasing trend. The result of future temperature from SDSM for RCP4.5 and RCP8.5 show increased rate on annual basis except 202s for RCP4.5. The maximum increasing value will occur for RCP8.5 in the 2020s and 2080s with a value of 1.85°C and 2.82°C for minimum and maximum temperature respectively. Downscaled precipitation results of future time interval of this study indicated decreased precipitation value for both RCP4.5 and RCP8.5 on annual basis. This, may increase water availability stresses in the study area. Therefore, this facilitate the decision makers to incorporate climate change scenarios for devising sustainable strategies, including: water harvesting technologies, supplementary irrigation, using improved seeds, which can tolerate moisture stresses, afforestation and reforestation programs, and soil and water conservation techniques. Moreover, crop diversifications, agricultural extension services access, related strategies, and measures are highly recommended for climate change resiliencies.
Abstract: Statistical downscaling models for temperature and precipitation in Borkena River Catchment, have been developed and applied to calculate the changes in historic, current and future climate changes. Projected changes in precipitation and temperature were analyzed using the outputs from GCMs and stations data (1976-2005) which were collected from 4 ...
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Assessment of Potential Suitable Surface Irrigation Area in Borkena River Catchment, Awash Basin, Ethiopia
Kasye Shitu,
Shemelis Berhanu
Issue:
Volume 9, Issue 5, October 2020
Pages:
98-106
Received:
18 March 2020
Accepted:
15 April 2020
Published:
24 September 2020
Abstract: Although Ethiopia has abundant land for irrigation, only a fraction of its potential land is being utilized and the economy of the country subjected to a direct impact of climate change. So, assessment of land suitability for irrigation purpose is important to utilize the land resources efficiently and for the sustainable production of crops and food security of the ever increasing people in the country especially the study area. This study was initiated to assess the land resources which is potentially suitable for surface irrigation in Borkena watershed by using Geographic Information System (GIS). To identify the land which is suitable for irrigation purpose, the following factors such as soil type, slope, land use/cover and distance from water supply (sources) were taken into account and classified based on the FAO guideline for land evaluation in to S1, S2, S3 and N suitability classes independently. The final existing and potentially irrigable land was identified by weighting overlay these factors of suitability. The suitability analysis of the parameters indicates that 90.65% of slope, 72.03% of soil depth, 94.73% distance from a water source of the study area, 100% soil drainages and 100% of soil texture were identified in the range of highly suitable (S1) to marginal suitable (S3) for surface irrigation. But, when all the above physical suitable area determination factors were weighted together using weighted overlay in Arc GIS software by restricted other land use/cover for irrigation development without agricultural land indicates only 16.13% highly suitable (S1), 47.12% moderately suitable (S2), 31.58 marginally suitable (S3) and 5.17% non-suitable (N) area for surface irrigation development.
Abstract: Although Ethiopia has abundant land for irrigation, only a fraction of its potential land is being utilized and the economy of the country subjected to a direct impact of climate change. So, assessment of land suitability for irrigation purpose is important to utilize the land resources efficiently and for the sustainable production of crops and fo...
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Hydrogeological Assessments of Impacts of Irrigation on Alluvial Water Table of Delta of Senegal River
Abdoul Aziz Gning,
Alassane Thiam,
Raymond Malou,
Mapathé Ndiaye
Issue:
Volume 9, Issue 5, October 2020
Pages:
107-122
Received:
15 September 2020
Accepted:
5 October 2020
Published:
22 October 2020
Abstract: Building dams on the Senegal River has facilitated the development of irrigated farming in Delta of Senegal River. However, this practice is threatened by the increasing degradation of soils mainly caused by salinization. The main cause of this problem is the presence of a salty aquifer at a low depth. Nevertheless, the characteristics and functioning of this aquifer are not well known. The main objective of this study, funded by Wallonie-Brussels International, is a contribution to the characterization of the hydrodynamic functioning, the hydro geochemistry of the aquifer and to identify the impact on agricultural waters. A two-step methodology has been developed: Firstly, a regional survey has been performed in the whole delta; secondly an irrigation plot has been monitored to have a detailed description of the groundwater dynamic and of the transport of salt under irrigation. Results of the regional survey show (1) the main factors that explain the fluctuation of the groundwater level are the artificial high water levels in the River, rice growing and to a lesser extent precipitation and (2) the high salt concentration in the upper aquifer. The monitoring of the Ndelle rice growing area (30 km to the North-East of Saint-Louis) has allowed calculating water and salt budgets at the scale of the irrigation plot. The influence of the irrigation on the groundwater levels has also been studied.
Abstract: Building dams on the Senegal River has facilitated the development of irrigated farming in Delta of Senegal River. However, this practice is threatened by the increasing degradation of soils mainly caused by salinization. The main cause of this problem is the presence of a salty aquifer at a low depth. Nevertheless, the characteristics and function...
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