Evidence for the occurrence of hydrogeochemical processes in the groundwater of Khoy plain,northwestern Iran,using ionic ratios and geochemical modeling     

Rahim Barzegar  Asghar Asghari Moghaddam  Amir Hossein Nazemi  Jan Adamowski 《Environmental Earth Sciences》2018,77(16):597

Rapid population growth, industrialization, and agricultural expansion in the Khoy area (northwestern Iran) have led to its dependence on groundwater and degradation of groundwater quality. This study attempts to decipher the major processes and factors that degrade the groundwater quality of the Khoy plain. For this purpose, 54 groundwater samples from unconfined and confined aquifers of the plain were collected in July 2017 and analyzed for major cations and anions (Na, K, Ca, Mg, HCO₃, SO_4, and Cl), minor ions (NO₃ and F), and Al. Magnesium and bicarbonate were identified as the dominant cation and anion, respectively. Several ionic ratios and geochemical modeling using PHREEQC indicated that the most important hydrogeochemical processes to affect groundwater quality in the plain were weathering and dissolution of evaporitic and silicate minerals, mixing, and ion exchange. There were smaller effects from evaporation and anthropogenic factors (e.g., industries). Results showed that the high salinity of the groundwater in the northeast area of the plain was due to the high solubility of the evaporitic minerals, e.g., halite and gypsum. Reverse ion exchange and the contribution of mineral dissolution were more significant than ion exchange in the northeastern part of the plain. Elevated salinity of the groundwater in the southeast was attributed mostly to reverse ion exchange and somewhat to evaporation.  相似文献   

Application of copula modelling to the performance assessment of reconstructed watersheds   总被引：3，自引：3，他引：0  

Alireza Nazemi  Amin Elshorbagy 《Stochastic Environmental Research and Risk Assessment (SERRA)》2012,26(2):189-205

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Compounding effects of human activities and climatic changes on surface water availability in Iran     

Ashraf  Samaneh  AghaKouchak  Amir  Nazemi  Ali  Mirchi  Ali  Sadegh  Mojtaba  Moftakhari  Hamed R.  Hassanzadeh  Elmira  Miao  Chi-Yuan  Madani  Kaveh  Mousavi Baygi  Mohammad  Anjileli  Hassan  Arab  Davood Reza  Norouzi  Hamid  Mazdiyasni  Omid  Azarderakhsh  Marzi  Alborzi  Aneseh  Tourian  Mohammad J.  Mehran  Ali  Farahmand  Alireza  Mallakpour  Iman 《Climatic change》2019,152(3-4):379-391

Climatic Change - By combining long-term ground-based data on water withdrawal with climate model projections, this study quantifies the compounding effects of human activities and climate change...  相似文献   

Daily reference evapotranspiration modeling by using genetic programming approach in the Basque Country (Northern Spain)     

Jalal Shiri  Özgur Kişi  Gorka Landeras  José Javier López  Amir Hossein Nazemi  Louis C.P.M. Stuyt 《Journal of Hydrology》2012

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Pseudo-static bearing capacity of shallow foundations on heterogeneous marine deposits using limit equilibrium method     

Ardavan Izadi  Mahsa Nazemi Sabet Soumehsaraei  Ali Ghorbani 《Marine Georesources & Geotechnology》2013,31(10):1163-1174

Abstract

By application of the limit equilibrium method associated with Coulomb failure mechanism, the effect of variation of undrained shear strength with depth on seismic bearing capacity was evaluated. The approach followed in this study to take into account seismic forces is pseudo-static. It is also assumed that the occurrence of an earthquake does not have any effects on the values of soil cohesion. Two different marine soil deposits exhibiting linear and bilinear variations of undrained shear strength with depth were considered. The undrained bearing capacity factor has been computed as a function of dimensionless parameters of λ₁B/c₀, λ₂B/c₀, and Z_t/B. The results of this paper have been compared with solutions reported in the literature, and the consistency of the results confirmed the ability of Coulomb failure mechanism and its corresponding limit equilibrium method formulation in static condition. Furthermore, the pseudo-static bearing capacity of shallow foundations on heterogeneous marine deposit is addressed. Finally the results of this study presented in the form of table and design charts.  相似文献   

Numerical analyses of tunnel collapse and slope stability assessment under different filling material loadings: a case study     

Zeinab?Aliabadian  Mansour?SharafisafaEmail author  Mohammad?Nazemi  Alireza?Rezazadeh?Khamene 《Arabian Journal of Geosciences》2015,8(3):1229-1242

To transfer the excess water from Sabzkouh River in central Iran to cities beyond the river, a mechanized tunnel is being excavated. During construction and support installation in the first 100 m, tunnel roof collapse occurred and was followed by ground settlement, so that a cavity was developed in ground surface. The cavity had to be filled in a short time before rainy season, since the water flow through cavity could extend the collapse area in both tunnel roof and ground surface. In order to fill the cavity, some filling methods with different materials consist of in situ soil, lightweight concrete, and pumice aggregate lightweight concrete (PALWC) were suggested. To analyse the load distribution and minimize the costs, a three-dimensional analysis was carried out. Tunnel support system was simulated numerically to further evaluate loading state on support system under different material loadings. Mohr-Coulomb material model was used to allow material failure. The modelling procedure was based on actual construction procedure. Firstly, in situ model was modelled without any excavation and was run to establish pre-stresses and displacement, then slope was supported, the tunnel was excavated and support was installed and finally cavity was simulated. The numerical results show that filling the cavity with soil will result in over loading on the support system and leads to instability of the slope. Other two suggested filling materials have acceptable load on support system, but PALWC was selected as the best filling material having minimum loading and guarantees slope stability.  相似文献   

Forms and drivers of annual streamflow variability in the headwaters of Canadian Prairies during the 20th century          下载免费PDF全文

Ali Nazemi  Howard S. Wheater  Kwok Pan Chun  Barrie Bonsal  Muluneh Mekonnen 《水文研究》2017,31(1):221-239

Headwater streamflows in the Rocky Mountain foothills are the key to water availability in the Canadian Prairies. Headwater characteristics, however, have been and continue to be subject to major variability and change. Here, we identify various forms of change in the annual mean streamflow and timing of the annual peak and attempt to distinguish between the effects of multiple drivers using a generalized regression scheme. Our investigation shows that the Pacific Decadal Oscillation (PDO) is the main driver of significant monotonic trends and shifts in the central tendency of annual mean streamflow in major headwaters. In parallel, the cumulative effects of non‐PDO climatic drivers and human‐induced land use and land management are the main causes of significant variations in the timing of the annual peak. Additional analyses show that time sequences with significant trends in annual mean streamflow and timing of the annual peak coincide with those that show significant trends in the PDO or non‐PDO component of the air temperature, respectively. The natural streamflow characteristics are substantially perturbed by anthropogenic river flow regulation, depending on the form of change and/or the level of regulation. Evidence suggests that the general tendency of human regulation is to alleviate the severity of above‐ and below‐average streamflow conditions; however, it may also intensify the variability in natural streamflow characteristics during drier years and/or those with earlier annual peak timing. These are circumstances to which the regional water resource system is vulnerable. Our findings are important for the provision of effective regional water resource management in the Canadian Prairies and contribute to a better understanding of the complex interactions between natural and anthropogenic drivers in coupled human–water systems.  相似文献   

Comparison of linear and nonlinear forms of isotherm models for Zn(II) and Cu(II) sorption on a kaolinite     

Shahram?Shahmohammadi-KalalaghEmail author  Hossein?Babazadeh  Amirhossein?Nazemi 《Arabian Journal of Geosciences》2015,8(1):397-402

The most appropriate method in designing the adsorption systems and assessing the performance of the adsorption systems is to have an idea on adsorption isotherms. Comparison analysis of linear least square method and nonlinear method for estimating the isotherm parameters was made using the experimental equilibrium data of Zn(II) and Cu(II) onto kaolinite. Equilibrium data were fitted to Freundlich, Langmuir, and Redlich–Peterson isotherm equations. In order to confirm the best-fit isotherms for the adsorption system, the data set using the chi-square (χ ²), combined with the values of the determined coefficient (r ²) was analyzed. Nonlinear method was found to be a more appropriate method for estimating the isotherm parameters. The best fitting isotherm was the Langmuir and Redlich–Peterson isotherm. The Redlich–Peterson is a special case of Langmuir when the Redlich–Peterson isotherm constant g was unity. The sorption capacity of kaolinite to uptake metal ions in the increasing order was given by Cu (4.2721 mg/g)?<?Zn (4.6710 mg/g).  相似文献   

Hybrid modelling approach to prairie hydrology: fusing data-driven and process-based hydrological models     

Balew A. Mekonnen  Alireza Nazemi  Kerry A. Mazurek  Amin Elshorbagy  Gordon Putz 《水文科学杂志》2013,58(9):1473-1489

Abstract

Much of the prairie region in North America is characterized by relatively flat terrain with many depressions on the landscape. The hydrological response (runoff) is a combination of the conventional runoff from the contributing areas and the occasional overflow from the non-contributing areas (depressions). In this study, we promote the use of a hybrid modelling structure to predict runoff generation from prairie landscapes. More specifically, the Soil and Water Assessment Tool (SWAT) is fused with artificial neural networks (ANNs), so that SWAT and the ANN module deal with the contributing and non-contributing areas, respectively. A detailed experimental study is performed to select the best set of inputs, training algorithms and hidden neurons. The results obtained in this study suggest that the fusion of process-based and data-driven models can provide improved modelling capabilities for representing the highly nonlinear nature of the hydrological processes in prairie landscapes.