The Experts below are selected from a list of 57033 Experts worldwide ranked by ideXlab platform
Masaki Sawamoto - One of the best experts on this subject based on the ideXlab platform.
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evaluation of Groundwater Resources in wide inundation areas of the mekong river basin
Journal of Hydrology, 2007Co-Authors: So Kazama, Priyantha Ranjan, Terumichi Hagiwara, Masaki SawamotoAbstract:Severe floods can have disastrous impacts and cause wide ranging destruction in the Mekong River basin. At the same time Groundwater Resources are significantly influenced and extensively recharged by flood water in inundation areas of the basin. This study determines the variation of Groundwater Resources caused by flooding over inundated areas located in lower part of the Mekong River basin using numerical modeling and field observations. The inundation calculations have been evaluated using satellite image outputs. Comparing large, medium and small flood events, we conclude that flood control which reduces the area of inundation, results in a reduction of Groundwater Resources in the area. In 1993, a 19% reduction in inundation areas resulted in a 31% reduction in Groundwater storage. In 1998, a 44% reduction in inundation areas led to a 42% reduction in Groundwater storage. Thus, while flood control activities are vital to reduce negative flood impacts in the Mekong River basin, they also negatively impact Groundwater Resources in the area.
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Effects of climate change on coastal fresh Groundwater Resources
Global Environmental Change, 2006Co-Authors: Priyantha Ranjan, So Kazama, Masaki SawamotoAbstract:Abstract This study evaluates the impacts of climate change on fresh Groundwater Resources specifically salinity intrusion in water Resources stressed coastal aquifers. Our assessment used the Hadley Centre climate model, HadCM3 with high and low emission scenarios (SRES A2 and B2) for years 2000–2099. In both scenarios, the annual fresh Groundwater Resources losses indicate an increasing long-term trend in all stressed areas, except in the northern Africa/Sahara region. We also found that precipitation and temperature individually did not show good correlations with fresh Groundwater loss. However, the relationship between the aridity index and fresh Groundwater loss exhibited a strong negative correlation. We also discuss the impacts of loss of fresh Groundwater Resources on socio-economic activities, mainly population growth and per capita fresh Groundwater Resources.
Petra Doll - One of the best experts on this subject based on the ideXlab platform.
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impact of climate change on renewable Groundwater Resources assessing the benefits of avoided greenhouse gas emissions using selected cmip5 climate projections
Environmental Research Letters, 2013Co-Authors: Felix T Portmann, Petra Doll, Stephanie Eisner, Martina FlorkeAbstract:Reduction of greenhouse gas (GHG) emissions to minimize climate change requires very significant societal effort. To motivate this effort, it is important to clarify the benefits of avoided emissions. To this end, we analysed the impact of four emissions scenarios on future renewable Groundwater Resources, which range from 1600 GtCO2 during the 21st century (RCP2.6) to 7300 GtCO2 (RCP8.5). Climate modelling uncertainty was taken into account by applying the bias-corrected output of a small ensemble of five CMIP5 global climate models (GCM) as provided by the ISI-MIP effort to the global hydrological model WaterGAP. Despite significant climate model uncertainty, the benefits of avoided emissions with respect to renewable Groundwater Resources (i.e. Groundwater recharge (GWR)) are obvious. The percentage of projected global population (SSP2 population scenario) suffering from a significant decrease of GWR of more than 10% by the 2080s as compared to 1971–2000 decreases from 38% (GCM range 27–50%) for RCP8.5 to 24% (11–39%) for RCP2.6. The population fraction that is spared from any significant GWR change would increase from 29% to 47% if emissions were restricted to RCP2.6. Increases of GWR are more likely to occur in areas with below average population density, while GWR decreases of more than 30% affect especially (semi)arid regions, across all GCMs. Considering change of renewable Groundwater Resources as a function of mean global temperature (GMT) rise, the land area that is affected by GWR decreases of more than 30% and 70% increases linearly with global warming from 0 to 3 ° C. For each degree of GMT rise, an additional 4% of the global land area (except Greenland and Antarctica) is affected by a GWR decrease of more than 30%, and an additional 1% is affected by a decrease of more than 70%.
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vulnerability to the impact of climate change on renewable Groundwater Resources a global scale assessment
Environmental Research Letters, 2009Co-Authors: Petra DollAbstract:Climate change will lead to significant changes of Groundwater recharge and thus renewable Groundwater Resources. Using the global water Resources and use model WaterGAP, the impact of climate change on Groundwater recharge and the number of affected people was computed for four climate scenarios by two climate models. Vulnerability of humans to decreased Groundwater Resources depends on both the degree of decrease and the sensitivity of the human system to the decrease. For each grid cell, a sensitivity index composed of a water scarcity indicator, an indicator for dependence of water supply on Groundwater and the Human Development Index was quantified. Combining per cent Groundwater recharge decrease with the sensitivity index, global maps of vulnerability to the impact of decreased Groundwater recharge in the 2050s were derived. In the A2 (B2) emissions scenario, 18.4–19.3% (16.1–18.1%) of the global population of 10.7 (9.1) billion would be affected by Groundwater recharge decreases of at least 10%, and 4.8–5.7% (3.8–3.8%) of the global population would be in the two highest vulnerability classes. The highest vulnerabilities are found at the North African rim of the Mediterranean Sea, in southwestern Africa, in northeastern Brazil and in the central Andes, which are areas of moderate to high sensitivity. For most of the areas with high population density and high sensitivity, model results indicate that Groundwater recharge is unlikely to decrease by more than 10% until the 2050s. However, a fifth to a third of the population may be affected by a Groundwater recharge increase of more than 10%, with negative impacts in the case of shallow water tables. The spatial distribution of vulnerability, even at the continental scale, differs more strongly between the two climate models than between the two emissions scenarios.
Dagnachew Daniel Molla - One of the best experts on this subject based on the ideXlab platform.
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simulated surface and shallow Groundwater Resources in the abaya chamo lake basin ethiopia using a spatially distributed water balance model
Journal of Hydrology: Regional Studies, 2019Co-Authors: Dagnachew Daniel Molla, Tenalem Ayenew Tegaye, Christopher G FletcherAbstract:Abstract Study region The volcano-tectonic lakes basin of Abaya-Chamo is part of the Main Ethiopian Rift system and exhibits large variations in geomorphology, physiography and climate between the rift floor and the plateau. Study focus Despite the importance of streamflow for water Resources management and planning in the basin, many of the rivers there are ungauged. To make quantitative estimates of streamflow for spatially resolved water availability in such a highly heterogeneous environment, therefore, requires numerical modeling. This study is the first to quantify the surface and shallow Groundwater Resources in Abaya-Chamo, and to validate the physically fully distributed hydrologic model WetSpass under highly data-limited conditions, in a complex two-lake environment. New hydrological insights Simulated total river flow and estimated baseflow were verified at 15 gauging stations, with a good agreement. The WetSpass model is shown to be suitable for such a complex setting with a correlation coefficient of 0.95 and 0.97 for total flow and baseflow respectively at a statistically significant level (p-value
Romain Chesnaux - One of the best experts on this subject based on the ideXlab platform.
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closed form analytical solutions for assessing the consequences of sea level rise on Groundwater Resources in sloping coastal aquifers
Hydrogeology Journal, 2015Co-Authors: Romain ChesnauxAbstract:The impacts of sea-level rise due to climate change on seawater intrusion in sloping-shore coastal unconfined aquifers are investigated. The study provides four closed-form analytical solutions for: (1) assessing the change in water-table elevation of coastal aquifers resulting from sea-level rise; (2) calculating the magnitude of the change of the saltwater inland toe migration within coastal aquifers in a context of sea-level rise; (3) measuring the change of Groundwater travel times through coastal aquifers in a context of sea-level rise, and (4) calculating the change in the quantity (changes of volume) of coastal fresh Groundwater Resources in a context of sea-level rise. The solutions apply to Dupuit-flow type conditions considering one-dimensional horizontal flow for homogenous and isotropic unconfined aquifers recharged by constant surface infiltration and discharging to the ocean, under steady-state conditions and assuming a sharp interface of the saltwater/freshwater transition zone. Examples are provided to illustrate how to apply the new solutions and conduct sensitivity analyses of the critical parameters involved in the equations. Taking into account the angle of the shore slope, these solutions constitute new analytical tools aiming to better measure the effects of land-surface inundation and anticipate changes in Groundwater Resources in coastal aquifers in a context of climate change.
Stefan Uhlenbrook - One of the best experts on this subject based on the ideXlab platform.
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impacts of sea level rise and Groundwater extraction scenarios on fresh Groundwater Resources in the nile delta governorates egypt
Water, 2018Co-Authors: Marmar Mabrouk, Andreja Jonoski, Gualbert Oude H P Essink, Stefan UhlenbrookAbstract:As Egypt's population increases, the demand for fresh Groundwater extraction will intensify. Consequently, the Groundwater quality will deteriorate, including an increase in salinization. On the other hand, salinization caused by saltwater intrusion in the coastal Nile Delta Aquifer (NDA) is also threatening the Groundwater Resources. The aim of this article is to assess the situation in 2010 (since this is when most data is sufficiently available) regarding the available fresh Groundwater Resources and to evaluate future salinization in the NDA using a 3D variable-density Groundwater flow model coupled with salt transport that was developed with SEAWAT. This is achieved by examining six future scenarios that combine two driving forces: increased extraction and sea level rise (SLR). Given the prognosis of the intergovernmental panel on climate change (IPCC), the scenarios are used to assess the impact of Groundwater extraction versus SLR on the seawater intrusion in the Delta and evaluate their contributions to increased Groundwater salinization. The results show that Groundwater extraction has a greater impact on salinization of the NDA than SLR, while the two factors combined cause the largest reduction of available fresh Groundwater Resources. The significant findings of this research are the determination of the Groundwater volumes of fresh water, brackish, light brackish and saline water in the NDA as a whole and in each governorate and the identification of the governorates that are most vulnerable to salinization. It is highly recommended that the results of this analysis are considered in future mitigation and/or adaptation plans.
