Groundwater is the most important source of fresh water supply in arid and semi-arid regions around the world, so it is necessary to maintain it through proper management in the use of these ...resources. Predicting areas of the aquifer that are most likely to be vulnerable is a powerful tool for optimally managing groundwater resources. Using numerical models, it is possible to predict how the aquifer reacts to the harvesting and feeding of the aquifer, with the prevailing trend or different management scenarios. The purpose of this study is to evaluate the effect of current management plans of the aquifer and the catchment area of the Jajroud River on changes in aquifer water levels and changes in nitrate ion concentration in the Varamin Plain, using numerical modeling. In this study, the effect of aquifer and catchment management plans of Jajrud River on changes in aquifer water level and changes in nitrate ion concentration in Varamin Plain, using numerical modeling. In this study, first a quantitative model was prepared in GMS software using MODFLOW code and then qualitative data were entered into the model. MT3D code was used to run the model. The model was simulated in both stable and unstable modes. After calibrating the model, the hydrodynamic coefficients were corrected and then, using the obtained model, the quantitative and qualitative behavior of the aquifer for the coming years was predicted for two management scenarios. The resulting model showed that with the continuation of the current trend in the aquifer (first scenario), the trend of quantitative and qualitative decline of the aquifer will continue as in previous years, but in the second scenario, with reduced harvesting from wells, municipal wastewater treatment plant will be commissioned. The artificial feeding of the aquifer and the use of the effluent of the Tehran water treatment plant to irrigate the Varamin Plain will significantly reduce the water level decline. Comparison of model implementation in the first and second scenarios shows that with the implementation of planned projects, part of the quantitative problems of the aquifer, especially in the northern areas of the plain will be reduced, so that in some areas, groundwater loss calculated in the quantitative model of the first scenario (until 1420) is reduced by about 30 to 40 meters. The output maps of the qualitative model of the first scenario show that in 1420 the concentration of nitrate in a large part of the aquifer will reach over 40 mg/L, which indicates serious health threats to the region. Simulation in the second scenario shows that the implementation of artificial feeding plan and feeding the aquifer with the effluent of the wastewater treatment plant (with a concentration of 50 mg/L) will not have much effect on reducing nitrate in the aquifer. In general, the implementation of nutrition and consumption management plans in the Varamin aquifer can only lead to a reduction in the quantitative and qualitative decline of groundwater in the aquifer that does not significantly reduce the percentage of water entering the aquifer. Certainly, using the current management methods (second scenario) will not have much effect on improving the aquifer. In addition to the plan to import wastewater from the Tehran treatment plant to the Varamin Plain, the plain should continue to be fed from the Jajrud River as a suitable natural feeding source.
A Budai Termálkarszt (BTK) fluidum-fejlődéstörténetét az ásványparagenezisek tükrében a késő-miocén fedett karbonátos állapottól vizsgáltuk. Ekkor a termikus felhajtóerő vezérelte a felszínalatti ...vízáramlást. Később, a Budai-hegység kiemelkedésével és a csapadékvíz beszivárgásával megkezdődött a vízszint különbségek által vezérelt vízáramlási rendszerek kialakulása. További változást okozott a Gödöllői-dombság kiemelkedése, mely a Budai-hegység kiemelt területei mellett a keleti medencerész felől is domborzati hajtóerőt biztosított. A meginduló beszivárgás lehetővé tette a fedő sziliciklasztos képződmények nátrium-kloridos vizeinek karbonátos víztartóba történő lejutását. Jelenleg a Budai-hegység és tágabb környezete a BTK áramlási rendszerének nyugati félig fedett részét, míg a Gödöllői-dombságtól a Dunáig tartó terület a rendszer keleti, fedett részét képezi. A BTK összefüggő áramlási rendszerében hidrosztatikus közeli nyomásviszonyok uralkodnak. A rendszer regionális és köztes megcsapolódási területei a Duna mentén húzódnak. A helyi, köztes és regionális áramlási rendszerek különbségeit a nyugati, félig fedett terület forrásai jelzik. A jelenkori vízáramlás domináns hajtóereje a vízszintkülönbségekből fakad, asszimmetrikus jellege a hidrosztratigráfiai helyzet, valamint a keleti és nyugati medencerészek közötti beszivárgáskülönbség következménye. A Duna alatt Ny–K irányú regionális átáramlás zajlik. A regionális feláramlás hidrotermális komponense NaCl-os medenceeredetű vízzel egészül ki. A meteorikus eredetű, langyos köztes, ill. a hideg helyi vízáramlásokban Mg2+ és SO42- gazdag vizek jellemzőek, a medenceeredtű fluidomok jelenléte itt nem bizonyított. Az eredmények rámutatnak a rendszer hőmérsékleti eloszlását meghatározó folyamatokra, valamint a fedőüledékek hő felhalmozódásában betöltött szerepére. A rózsadombi és a Gellért-hegy előterében található források fizikai-kémiai tulajdonságok szerinti elkülönülését szerkezeti és a két áramlási rendszer különbségei okozhatják. A Gellért-hegynél csak termálvíz lép felszínre, míg a Rózsadombnál langyos és termálvíz megcsapolódás egyaránt zajlik. A különbség a hidrotermális vizek összetételében, eltérő forrásterületre és vízkémiai folyamatokra utal. A déli rendszer szulfát-többlete az evaporit összletekkel, a központi rendszer szulfátja medenceeredetű kén-hidrogénnel hozható összefüggésbe. A rózsadombi langyos meteorikus vizek szulfát forrása a fedő képződménybek piritje lehet. A fluidum-fejlődéstörténeti tanulmány eredményei hozzájárulnak a barlangképződési folyamatok értelmezéséhez.
Since 2007, Naturally Occurring Radioactive Materials (NORM) such as uranium-238 and radon-222 etc. in groundwater from the Community Water-supply Systems (CWS) in two islands have been studied in ...South Korea. In 71 samples from Ganghwa (G) Island, the maximum value of uranium-238 concentration is 72.21 μg/L. 3 CWSs (4.2%) exceeded the Maximum Contaminant Level (MCL) of 30 μg/L for uranium-238. The maximum value of radon-222 activity is 614 Bq/L. 28 CWSs (39.4 %) did not meet the United States Environment Protection Agency (US EPA) proposed Alternative Maximum Contaminant Level (AMCL) of 148 Bq/L for radon-222. At all CWS that did not meet the US EPA’s MCL or AMCL, some appropriate actions were taken such as water treatment, alternative well development, mixing water of different origins, and so forth. In the 52 CWSs of Jeju (J) Island, the maximum value of uranium-238 and radon-222 concentrations are 1.37 μg/L and 94.83 Bq/L, respectively. All values for uranium-238, gross alpha, and radon-222 meet MCL and proposed AMCL of US EPA drinking water standard. The two islands have different geological settings that are believed to be the causes of the big differences in the NORM levels. Geologically an old island has much higher NORM values than a young island formed in the Quaternary Period due to hydrogeological factors such as recharge and infiltration rates of precipitation. The residence times in the aquifers for water-rock (mineral) interactions are very different from each other.
The multigrid method used with OpenMP/MPI hybrid parallel programming models is expected to play an important role in large-scale scientific computing on post-peta/exa-scale supercomputer systems. In ...the present work, the effect of sparse matrix storage formats on the performance of parallel geometric multigrid solvers was evaluated, and a new data structure for the Ellpack-Itpack (ELL) format is proposed. The proposed method is implemented for pGW3D-FVM, a parallel code for 3D groundwater flow simulations using the multigrid method, and the robustness and performance of the code was evaluated on up to 4,096 nodes (65,536 cores) of the Fujistu FX10 supercomputer system at the University of Tokyo. The parallel multigrid solver using the ELL format with coarse grid aggregation provided excellent performance improvement in both weak scaling (13%–35%) and strong scaling (40%–70%) compared to the original code using the CRS format.
In order to alleviate the contradictions about water resources shortage and socio-economic development in Northern Shaanxi, the water resources and their availability were studied. Through use the ...method of surface water resources deducte river ecological basic flow and flood discharge, calculated the surface available water resources and total available water resources of Northern Shaanxi, summarized their distribution characteristics. Study result showed that the available water resources of Northern Shaanxi is low, only 1.6 billion m3, available rate is 40%, water resources and their availability principally distribute in Yulin.
Density-driven groundwater flow is a complicated nonlinear problem in groundwater hydraulics. The local Petrov-Galerkin method is a promising meshless scheme that is used for solving several ...difficult problems in different areas. This method applies the weak form of governing equations to the local mesh around every node. The nodes can be randomly distributed in the domain and on the global boundary. Therefore, this method is characterized as meshless. The unknown potentials and concentrations in all of the nodes are approximated by interpolation to obtain a system of linear equations. Solving this system of equations leads to the numerical solution for the main problem. In this paper, a combination of the radial basis function interpolation and the local Petrov-Galerkin method is used to solve groundwater flow problem combined with the transport of pollution, which also influences the density of groundwater.
Two regional groundwater flow models (Neckar catchment, Germany, 14,000
km
2, and Southern Ouémé Basin, Benin, 11,000
km
2) were developed within the framework of the integrated management project ...‘RIVERTWIN’ (
www.rivertwin.org). Both models were evaluated with respect to the question if the chosen modelling approaches (multi-layered finite difference numerical flow modelling, steady state and transient) are appropriate in view of the existing management problems in the catchments, the data availability and the hydrogeological and hydrological conditions in the basins. It is shown that neither the model in the well-investigated, data-rich basin in Western Europe with its highly developed water related infrastructure, nor the model in the hydrogeologically less well-known and less developed basin in Western Africa provide results that are fully applicable to the main regional management tasks. In the case of the Ouémé, the groundwater related problems are foremost of local character and therefore cannot be addressed by regional models in a meaningful way. Data scarcity and complex, unfavourable geological conditions (crystalline rocks, discontinuous aquifers) support the conclusion that numerical 3D groundwater flow models are currently not helpful to manage groundwater related management problems in the Ouémé basin. A better understanding of regional hydrological surface and subsurface processes is required first. Methods for a reliable estimation of groundwater recharge and subsequently groundwater availability were identified as the most urgently needed tool for meaningful groundwater management in view of climatic, demographic and land use change. In the Neckar catchment the results of the analysis are less pronounced; here regional groundwater problems could clearly benefit from a physically based 3D model since the hydrogeological system is strictly stratified with several important aquifers in the vertical sequence. As a general conclusion it can be stated that regional scale groundwater flow modelling concepts seem to be difficult to integrate in management systems and difficult to transfer from one basin to another. This means the question of how to represent the groundwater resources appropriately has to be discussed very thoroughly for any new integrated water resources management problem. It is not possible to give a final recommendation on which modelling concept is the most appropriate one in regional integrated modelling and management. Hence, this article is only intended to provide an in depth discussion of the aspects that need to be considered in the process of choosing appropriate modelling concepts.
A new optimization formulation for dynamic groundwater remediation management is developed by simultaneously using well locations and the corresponding pumping rates as the decision variables. The ...genetic algorithm is applied to search for optimal pumping rates and the discrete space of well locations. The optimization model is applied to hypothetical, three-dimensional, contaminated aquifer systems with homogeneous and heterogeneous porous media properties. Optimal well locations and pumping rates obtained with the moving-well model are less expensive than solutions obtained with a comparable fixed-well model. Optimization with a linear objective function formulation identifies some of the optimal well locations obtained with a nonlinear formulation but results in higher pumping rates than the nonlinear formulation and ignores the higher drawdowns produced in low-permeability areas. Optimal well locations are found along the mass centerline of the contaminant plumes and in high-permeability areas in the heterogeneous system. Dynamic pumping rates and well locations produce more cost-effective solutions relative to a static model. The well location search path and convergence behavior indicate that the genetic algorithm is an effective alternative solution scheme and that well location optimization is more important than pumping rate optimization
Co-seismic groundwater-level and temperature changes caused by the Mw9. 0 Japan earthquake in Chinese mainland are described. The recorded water-level changes were mostly oscillations, with some step ...decreases mostly in the coastal area of Southeast China and step increases mostly in Northeast China and the North–south Seismic Belt. The water-temperature changes were mainly decrease with slow recovery in Sichuan-Yunnan, South China, and lower reaches of Jiangzhong, and sharp increase followed by sharp decrease, or vice versa, in North China and Northeast China. For wells that showed step changes in both water level and temperature, more showed them in the same direction than in the opposite direction.
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