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Holistic approach of GIS based Multi-Criteria Decision Analysis (MCDA) and WetSpass models to evaluate groundwater potential in Gelana watershed of Ethiopia 
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下载免费PDF全文 Appropriate quantification and identification of the groundwater distribution in a hydrological basin may provide necessary information for effective management, planning and development of groundwater resources. Groundwater potential assessment and delineation in a highly heterogeneous environment with limited Spatiotemporal data derived from Gelana watershed of Abaya Chamo lake basin is performed, using integrated multi-criteria decision analysis (MCDA), water and energy transfer between soil and plant and atmosphere under quasi-steady state (WetSpass) models. The outputs of the WetSpass model reveal a favorable structure of water balance in the basin studied, mainly using surface runoff. The simulated total flow and groundwater recharge are validated using river measurements and estimated baseflow at two gauging stations located in the study area, which yields a good agreement. The WetSpass model effectively integrates a water balance assessment in a geographical information system (GIS) environment. The WetSpass model is shown to be computationally reputable for such a remote complex setting as the African rift, with a correlation coefficient of 0.99 and 0.99 for total flow and baseflow at a significant level of p-value<0.05, respectively. The simulated annual water budget reveals that 77.22% of annual precipitation loses through evapotranspiration, of which 16.54% is lost via surface runoff while 6.24% is recharged to the groundwater. The calibrated groundwater recharge from the WetSpass model is then considered when determining the controlling factors of groundwater occurrence and formation, together with other multi-thematic layers such as lithology, geomorphology, lineament density and drainage density. The selected five thematic layers through MCDA are incorporated by employing the analytical hierarchy process (AHP) method to identify the relative dominance in groundwater potential zoning. The weighted factors in the AHP are procedurally aggregated, based on weighted linear combinations to provide the groundwater potential index. Based on the potential indexes, the area then is demarcated into low, moderate, and high groundwater potential zones (GWPZ). The identified GWPZs are finally examined using the existing groundwater inventory data (static water level and springs) in the region. About 70.7% of groundwater inventory points are coinciding with the delineated GWPZs. The weighting comparison shows that lithology, geomorphology, and groundwater recharge appear to be the dominant factors influence on the resources potential. The assessment of groundwater potential index values identify 45.88% as high, 39.38% moderate, and 14.73% as low groundwater potential zones. WetSpass model analysis is more preferable in the area like Gelana watershed when the topography is rugged, inaccessible and having limited gauging stations. 相似文献
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The eastern Ethiopian highland is endowed with large potential of water resources in terms of rainfall, groundwater and surface
water. Yet, due to overpumping of lake water and groundwater and environmental degradation, Lakes Haromaya and Adele have
completely dried up. The environmental degradation, due to deforestation and clearing of land for farming, has increased the
rate of siltation in the lakes that dramatically decreases the lakes’ volume and surface albedo, which increased the rate
of evaporation. The impact of these factors is aggravated due to decreasing net recharge to the lake and the alluvial aquifer.
Over the last 35 years, pumping of lake water for irrigation, mainly for subsistence farming, domestic and industrial use
shows an increasing trend. Hence, the available water for drinking and industrial purposes decreased drastically. In this
research, classical Penman aerodynamic combined energy budget, Penman nomogram methods, conventional soil moisture water balance
method and Penman–Monteith model were adopted to estimate free evaporation, actual and potential evapotranspirations. The
results indicate that evaporation is the dominant factor for the loss of water and water abstraction is 316% higher than the
effective precipitation, which is 110 mm/year. Therefore, overexploitation of the available resources has played an aggravating
role for the loss of the lakes in the area. The main cause for such resource depletion is the lack of integrated water resources
management strategies. The current water shortage in the area has mainly affected urban residents of Harar, Awoday and Alemaya
towns and the surrounding villages, which depend heavily on the two lakes. To alleviate the current crises interbasin water
transfer and rainwater harvesting would be possible alternatives besides ameliorating environmental situation of the basin. 相似文献
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Hydrochemical characterization of complex volcanic aquifers in a continental rifted zone: the Middle Awash basin, Ethiopia 总被引：2，自引：0，他引：2
Wakgari Furi Moumtaz Razack Tamiru Alemayehu Abiye Seifu Kebede Dagnachew Legesse 《Hydrogeology Journal》2012,20(2):385-400
The Middle Awash basin is an arid region in Ethiopia where surface waters are scarce and local communities are dependent on groundwater resources for water supply. The complex hydrogeological system of this basin has been conceptualized. Multivariate statistical analysis of hydrochemical variables and water isotopes were used to study the rock?Cwater interaction, geochemical reaction processes and the hydrological link between aquifers. Groundwaters from aquifers of the high-rainfall plateau bounding the rift are slightly mineralized, as well as depleted in ??18O and ??D, and contain 3H above 0.8?TU. This suggests a low degree of rock?Cwater interaction and that groundwater is under recharge from heavy rain that falls on surrounding highlands. On the other hand, groundwaters from aquifers of the rift floor are highly mineralized and show slight enrichment in ??18O and ??D with positive oxygen shift, but contain 3H below 0.8?TU. The positive oxygen shift in rift floor groundwaters may be caused by the isotopic exchange of oxygen between groundwater and aquifer materials during rock?Cwater interaction, whereas the low 3H content could be due to the decay of tritium along relatively long flow paths. The approach utilized in this study may be applicable to understanding hydrogeochemical processes in other complex volcanic terrains. 相似文献
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Jan Valenta Kryštof Verner Karel Martínek Tomáš Hroch David Buriánek Leta Alemayehu Megerssa Jan Boháč Muluken Kassa Ferdawok Legesse Meheret Yakob Bisrat Kebede Jiří Málek 《地球表面变化过程与地形》2021,46(15):3158-3174
Ground fissures, especially if they open due to a sudden collapse of the surface, is a serious risk for populated areas. Their common occurrence in unconsolidated sediments of the Main Ethiopian Rift was found to be mostly a result of piping. The fissures start by piping in linear sub-horizontal underground voids, which often propagate upwards resulting in ceiling collapse and formation of deep and long ground fissures with vertical walls. In the southern and central Main Ethiopian Rift the fissures pose a serious risk to infrastructure and settlements. The ground fissures are often linear (up to several kilometres long and often tens of metres deep) and accompanied by sinkholes (along the length). A detailed field mapping of the geological (rock composition, orientation and character of lithological boundaries, primary fabrics and brittle structures) and geomorphological features (especially a length, width and depth of fissures, sinkholes and gullies) followed by in situ seismic anisotropy measurements and a laboratory determination of the geomechanical properties of volcanoclastic deposits was carried out to investigate the ground fissures' origin. The conditions and factors leading to the formation of the ground fissures have been linked to: (a) the presence of regional normal faults and the associated extensional joints and (b) the alternation of lithological units with contrasting hydraulic permeability. The latter corresponds to a sequence of less permeable hard rocks (e.g., rhyolitic ignimbrites) overlain by heterogeneous, soft and permeable, unconsolidated volcaniclastic deposits with a low amount of clay (less than 10%). The ground fissures' occurrence has shown affiliation to areas which have a significantly high seismic anisotropy (more than 20% at the study sites), which can be used as a proxy to map out high risk areas prone to piping and ground fissure formation. 相似文献
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Integrated dynamic water and chloride balance models with a catchment‐scale hydrological model (PRMS) are used to investigate the response of a terminal tropical lake, Lake Abiyata, to climate variability and water use practices in its catchment. The hydrological model is used to investigate the response of the catchment to different climate and land‐use change scenarios that are incorporated into the lake model. Lake depth–area–volume relationships were established from lake bathymetries. Missing data in the time series were filled using statistical regression techniques. Based on mean monthly data, the lake water balance model produced a good agreement between the simulated and observed levels of Lake Abiyata for the period 1968–83. From 1984 onwards the simulated lake level is overestimated with respect to the observed one, while the chloride concentration is largely underestimated. This discrepancy is attributed to human use of water from the influent rivers or directly from the lake. The simulated lake level and chloride concentration are in better agreement with observed values (r2 = 0·96) when human water use for irrigation and salt exploitation are included in the model. A comparison of the simulation with and without human consumption indicates that climate variability controls the interannual fluctuations and that the human water use affects the equilibrium of the system by strongly reducing the lake level. Sensitivity analysis based on a mean climatic year showed that, after prolonged mean climatic conditions, Lake Abiyata reacts more rapidly to an abrupt shift to wetter conditions than to dry conditions. This study shows the significant sensitivity of the level and salinity of the terminal Lake Abiyata to small changes in climate or land use, making it a very good ‘recorder’ of environmental changes that may occur in the catchment at different time scales. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
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Wakgari Furi Moumtaz Razack Tigistu Haile Tamiru A. Abiye Dagnachew Legesse 《Environmental Earth Sciences》2011,62(6):1323-1335
Rise of groundwater level becomes an emerging concern at Wonji irrigation field, Main Ethiopian Rift. An integrated study
based on geophysical resistivity methods is conducted at Wonji wetland to understand the link between irrigation water and
the shallow aquifer system as well as to confirm the current concern of groundwater rise. The study was also intended to improve
the uncertainty of understanding the hydrogeology of Wonji wetland including the extent and direction of groundwater–surface
water interaction. The vertical and horizontal contacts between the different geological series of the Wonji area are resolved
with 2D high-resolution geophysical imaging. Results from both VES and 2D tomography show low resistivity layers under Wonji
irrigation field with narrow ranges in resistivity variation which corresponds to a homogeneous saturated layer. The geoelectric
sections reveal two fault systems running NW–SE and N–S directions which impede lateral groundwater flow. Furthermore, groundwater
is converged towards the Wonji irrigation site strained by these fault systems. The geophysical results show strong link between
irrigation water and the shallow unconfined aquifer as well as among the local and regional flow systems. 相似文献
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GeoJournal - Examining the spatial variation of surface temperature is an important criterion to create livable urban environment. To examine the cause of heat island variation in the study area... 相似文献
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