جستجوی مقالات مرتبط با کلیدواژه « ground water » در نشریات گروه « زمین شناسی »

Semnan plain with arid and semi-arid climate is situated in southern flank of Alborz range and north of great desert of Central Iran. In this study the result of analyses of major ions in 35 deep wells and qanats and oxygen-18 and deuterium stable isotopes in 5 wells and one sample of the river water have been used to access the chemical characteristics of groundwater. Hierarchical cluster analysis (HCA) has been used for classifying the water samples. The results show that the samples can be grouped into three main categories: (1) waters with highest bicarbonate content and lowest TDS, (2) waters with highest sulfate content and (3) chloride waters with maximum salt content. Checking the spatial distribution of the samples shows that the samples of each group are situated in a specific area; indicating similar affecting processes on water quality in each group. Mineral saturation index calculated with the PHREEQC software showed that the samples are super-saturated with respect to the carbonate mineral and under-saturated to saturated with respect to the gypsum and anhydrite and under-saturated with respect to the halite. Based on isotopic analysis, correlation coefficient and ion ratios, chloro-alkaline index and Gibbs plot of the chemical composition of the groundwater in Semnan plain are controlled by the intrusion of Abgram salt water and salt dissolution, groundwater residence time, silicate weathering, cation exchange, evaporation and agricultural return flow.

Droughts are the most destructive weather events which caused considerable damage to the natural resource sector as well as in human life. Minab river basin was selected because of Esteghlal dam and importance of groundwater and surface water resources and the plain located in this basin. The frequency of droughts was determined using RDI and SPI in rain gauge stations located in the study area. The results showed that both SPI and RDI index for mild and moderate drought frequency region were fitted. SPI based on the effective theory, showed better adaptability with the study area. Therefore the index was selected to assessment drought and water resources relationships. Then in order to evaluate the effect of drought on surface water resources the relationship between the annual mean changes discharge in hydrometric stations near the plain. The results showed that this relationship is statistically significant correlation. In the next step the effects of drought on groundwater resources were calculated by using the bivariate correlation, coefficient harvest and drought effects on groundwater level changes and were found to fall in the water level of all plains were affected by the drought, with high impact factor, except plain Mosaferabad because wells located on the second table and major portion of aquifer recharge it through hard formations highlands done and plain rain is less affected.

Waste disposal, is a method in which wastes are buried on sinkholes. The buried wastes caused environmental problems. One of these environmental problems is leaches mainly due to influence of precipitation and sometimes surface waters entering the wastes. The leaches consist of various materials. In this study, chemical properties of groundwater of upstream regions of Sanandaj landfill, regarding the suitability of water for drinking is examined.Hence, 5 wells around Sanandaj landfills were selected and 10 water samples were collected and evaluated during 2 seasons based on physical and chemical parameters such as odour, turbidity, colour, pH, TDS, TH, chloride, sulfate, sodium and nitrate. In order to determine the quality of water for drinking purpose, the results were compared with Standard index and Schoeller diagram for the classification of ground water. The result shows most samples are suitable for drinking purpose.

Understanding the interactions of ground water and surface water is one of the most important challenges among hydrogeologists. Hydraulic gradient between ground water and surface water, as well as hydraulic conductivity of streambed sediments are required to determine ground water and surface water exchanges. Minipiezometers are simple instruments that measure flow direction and hydraulic gradients between ground water and surface water. Often temporarily installed, minipiezometers are essentially small-scaled versions of piezometers, which are commonly used to make groundwater level measurements. By combining water table data with surface water level measurements, flow direction can be determined. Minipiezometers are typically used in the areas where many measurements are required. Commercial minipiezometers are available, but they are very expensive. The purpose of this paper is to design and construc a low-cost minipiezometer for measuring ground water and surface water exchanges. In this study, a minipiezometer was made by simple and available materials such as steel pipe, steel 3NPSoft rob, clear plastic hose, gas valves, hand vacuum pump, hammer, U-shape clear tubing, graduated manometer board, and graduated transparent plastic cylinder and was successfully tested in the Soleghan River in the west of Tehran.

Underground water resources in many regions of the world are the most important factor to create cities, and life in many areas depends on these waters. Also, in Islamshahr city, water supply of this area is ground water. Among 26 active wells in the rural part of city, by considering distribution of agricultural, residential and industrial areas, slope of the land (north west to south east), dispersion wells, having well’s information during 10 years and considering all Islamshar area, 14 wells were selected to study. The objective of this study is to evaluate the land use on the quality of water and study of process of changes on drinking water quality parameters in this area by using AqQa software, and GIS during 10 years (1385-1394). After study different elements and components of water and prepare their quality maps and determine the general trends of changes, it was known in the north west area, south west and south areas, most of chemical parameters of water have maximum concentration that in some cases these amounts are more than the limit set. Particularly for some elements like EC and TDS is more tangible. Finally, the study showed Geological structure, agricultural activities, Urban Development and population density are the most effective factors on the quality of ground water in Islamshahr city.

Studies show that earthquake causes chemical and physical changes in ground water. These changes can be recorded and used as geohydrologic precursors. Also according to recent research while earthquake and before, the waves of electromagnetic field of the earth vibrate, these vibrations are called magnetic anomalous. In earthquake knowledge, this type of anomalous is known as geohydrologic precursors. So the purpose of this research is to study the feasibility of the correlation between two precursors (geohydrologic and geomagnetic). In this study, to consider the effects of magnetic field on physical and chemical characteristics of water (i.e., electrical conductivity, total dissolved solids, and water level), a number of experiences have been done that can be used in short term and long term earthquake prediction. According to the results of statistical analysis, there is a meaningful partial correlation (confidence coefficient=95%) between magnetic field (geomagnetic precursors) and physical and chemical characteristics of water (geohydrologic precursors).

To determine the ground water potential of the karst aquifers، in the southwest of Izeh، three profiles and 62 vertical electrical sounding (VES) conducted by Schlumberger array، eight profiles were performed using dipole-dipole configuration، and 3-D configuration applied in two sites. However، Schlumberger tomography with high investigation depth (about 180 m) may be shows the different zone of karst aquifer but because of 50-100 m of VES spacing has not the detectability of cavities with lower than 50 m diameter. The results show that Ilam-Sarvak limestone is similar to hard rocks while Asmari formation has been identified as developed karst with high matrix porosity. The results in the 2-D geoelectrical tomography using a dipole-dipole configuration، shows that، compared to an electrode spacing of 5 m، an electrode spacing of 1 or 2 m has a higher ability to delineate karst voids. Because of the higher depth of the investigation، however، the longer electrode spacing allowed obtaining a comprehensive insight of different parts of karst regions. The high resolution 3-D electrical tomography has a good ability to detection of geological features and karst voids. The geoelectric results and interpretation of tomograms have been asserted by drilling success of four wells with high yield at Asmari formation and two wells with moderate yield at Ilam-Sarvak formation.

Before feeling water -shortage crisis human has understood the importance of water From the religious texts. Considering recent conditions of the world the water will replace most recent boundaries, at future. Imamzadeh Jaafar plain is located 5 kilometers northeast of Gachsaran, south of Kohgilooye and Boerahmad province. The plain has 61km 2 area extents and contains two, alluvial and carbonate aquifers. These aquifers supply the water needs, agricultural, industrial and domestic. Highly exploitation and transportation of groundwater resources, especially by National Oil Company, caused highly drawdown in alluvial aquifer, 1.85m in a 5 years period from 1361 to 1365 as reported by Mahab Ghods Consulting Engineers. There are two artificial recharge projects, 1 flood spreading system and 1 recharge ponds system, in the plain. To present the future water resources management program the hydrogeological behaviors of the alluvial aquifer and the effects of artificial recharge must be evaluated. To develop the conceptual model of aquifer required information, meteorological, water level in the observation wells, depth to bedrock, hydrodynamic coefficients, topography, water resources and …, were collected, field surveys were performed and required maps were prepared. Using conceptual model and MODFLOW PMWIN code the mathematical model of the plain was calibrated against water year 13 -81 and then verified against water year 1384 - 85. The verified model was used to predict future conditions of aquifer. The results implied the rapid response of aquifer to precipitation due to high aquifer transmissivity, positive water budget at year 1385 comparing year 65, change of direction of groundwaterflow from plain outlet to the center of plain in response to highly exploitation at the center of plain, water level in the wells located downward the flood spreading system will raise as to 6m and water level in t he wells located downward the recharge pond system will lower as 1 to m.