Publications by authors named "Walraevens K"

Hydrogeological numerical models are essential for assessing radioactive waste disposal by understanding groundwater flow systems. These models typically rely on hydraulic head data, with other state variables often underutilized in model inversions. In Flanders' Neogene aquifer, where safety studies for Boom Clay are ongoing, existing models face uncertainties due to dependence on hydraulic heads alone.

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Lake Tana basin encompasses a wide regional volcanic aquifer system, in the northwestern highlands of Ethiopia. It has significant water resource potential for water supply and irrigation purposes. The objective of this study was to assess the physiochemical characteristics of the surface water-groundwater and investigate the processes controlling groundwater chemistry.

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This work pursues the hydro-geochemical and isotopic characterization of the complex groundwater system of the Gioia Tauro Plain, one of the most important industrialized and agricultural coastal areas of southern Italy. The anthropic pressure exposes the water resources at risk of depletion and quality degradation making the plain groundwater a system of high scientific and social interest. The plain is characterized by a shallow aquifer, mostly recharged by local rains and a deep aquifer apparently less influenced by local precipitation.

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The water budget myth, which is the idea that safe pumping must not exceed the initial recharge, gave rise to a controversy about the role of recharge in assessing the sustainability of groundwater development. To refute the concept of safe yield, a simplified water budget equation is used, which equals the total pumping rate to the sum of capture and storage change. Since initial recharge and discharge are canceled out from this equation, it is concluded that sustainable pumping has nothing to do with recharge.

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Dhaka is one of the highly populated cities in the world. Increased urbanization and population growth in Dhaka are mostly dependent on groundwater, with 78% of the supply water coming from the Plio-Pleistocene Dupi Tila aquifer. This research was conducted with the objectives of identifying ion chemistry, hydrochemical processes and their relationship to groundwater quality and finding out the impact of over-exploitation on Dupi Tila aquifer.

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This study investigates the localities of low and high F groundwaters in the aquifer system on the flanks of Mount Meru to come up with guidelines to provide groundwater that can be used for drinking water supply without health impacts on the population. Our study focuses on parts of the flanks which were only partially or not at all covered by previous research. Results show that the groundwater chemistry of F-rich NaHCO alkaline groundwater in the area is controlled by dissolution of weathering aluminosilicate minerals, dissolution of F-bearing minerals, the precipitation of carbonate minerals as secondary products and the dissolution of magmatic gases.

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The population of the semi-arid areas of the countries in the East African Rift Valley (EARV) is faced with serious problems associated with the availability and the quality of the drinking water. In these areas, the drinking water supply largely relies on groundwater characterised by elevated fluoride concentration (> 1.5 mg/L), resulting from interactions with the surrounding alkaline volcanic rocks.

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The Ledo-Paniselian aquifer in Belgium has been proposed to offer unique opportunities to study groundwater recharge and flow in periglacial conditions during the Last Glacial Maximum (LGM), due to its location in the permanent permafrost area, south of the ice sheet at that time. A palaeoclimatic record had been set up previously for this aquifer, consisting of major ion chemistry, stable isotopes, radiocarbon and noble gases. In this paper, methane data have been used to further refine the paleoclimatic model, along with revisiting in detail the set of chemical data, focusing on the area where groundwaters, recharged around the LGM, are known to occur.

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Diffuse groundwater contamination by intense fertilizer use is a widespread problem in most of the agricultural regions in West-Europe and in many other countries worldwide. As a result elevated nitrate concentrations in groundwater are found, and as groundwater is the source of baseflow into rivers and streams, also surface waters show increased nitrate levels. Flanders in the north of Belgium is no exception and despite restrictions on the fertilizer use and remediation practices initiated in the mid-1990s, and still ongoing, in many stream monitoring points, peak concentrations are measured above the 50 mg/l criterium.

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The hydrogeochemical processes in the multilayer aquifers of southwest (SW) coastal area of Bangladesh provide important information for quantifying hydrochemical differences between different aquifers. Hydrogeochemical processes affecting groundwater chemistry in this coastal area have been evaluated by interpreting conventional plots, ionic delta, HFE-diagram, stable isotopes and geochemical modelling. The median TDS distribution of the aquifers has an increasing trend from below 1000 mg/l in the deep aquifer (DA) to 2622 mg/l in lower shallow aquifer (LSA) and 7012 mg/l in upper shallow aquifer (USA).

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Groundwater recharge estimation, aquifer response to meteorological variables, and evapotranspiration calculations have been performed on a semi-humid catchment, in northwestern Ethiopian plateau. The Soil Moisture Balance (SMB), WetSpass water balance model, Water Table Fluctuation (WTF), and Chloride Mass Balance (CMB) methods are applied to estimate the groundwater recharge. Accordingly, 431 mm, 462 mm, and 477 mm recharge amounts are estimated as mean annual value, respectively, using SMB, WetSpass, and CMB methods.

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Knowledge of the geographical distribution of soils is indispensable for policy and decision makers to achieve the goal of increasing agricultural production and reduce poverty, particularly in the Global South. A study was conducted to better understand the soilscapes of the Giba catchment (900-3300 m a.s.

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The desert of eastern Libya forms one of the most arid regions of the Sahara. The Great Man-Made River Project (GMRP) was established. It transports millions of cubic meters of water a day from desert wellfields to the coastal cities, where over 80% of the population lives.

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This paper describes a method for the extraction, separation, identification, and quantification of 77 pesticides (neutral, acidic, and basic) including some s-triazine metabolites. The method is appropriate for organically (e.g.

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