HYDROGEOLOGY
Year:2019 | Volume:4 | Issue:1 |Papers Count:12

Hydrodynamic coefficients of an aquifer are the most important hydrogeological information to describe its characteristics, and most of the research and implementation project depend on the existence of accurate hydrodynamic coefficients data. In this study, while quantitative study of groundwater resources of Evan Plain, the fuzzy inference model was developed to determine the hydrodynamic coefficients of the aquifer. These coefficients include transmissivity (T), storage coefficient (S), and hydraulic conductivity coefficient (K). One of the methods to determine these parameters is to perform a pumping test analysis, which is usually very costly in most areas, especially the arid regions due to increased drilling depth has many limitations. Another objective of this research is to investigate changes in hydrodynamic coefficients of the aquifer over time, which can be used to predict this information at unknown locations. Hydrodynamic parameters can change over time and place. Spatial variations are due to environmental changes. If the changes are due to the effect of recharge, discharge and compaction, this suggests that the use of a general function for the whole region cannot be a suitable method for estimating the parameters. The small difference between the values of the hydrodynamic coefficients estimated by the fuzzy method in comparison with the pumping method, which has an error of less than 0. 07, indicates the high accuracy of this method. Using the fuzzy logic method in determining hydrodynamic coefficients can greatly reduce the cost of pumping tests. Therefore, the use of fuzzy inference method to determine and estimate hydrodynamic coefficients can be useful in unspecified regions.

Monitoring and analysis of spring hydrograph is the best method to study of karstic reservoirs. The results can provide a significant insight to understand and management of these valuable resources. The main aim of this study is determine the characteristics of karstic aquifers from two spring, Barmejamal and Poto, located in south-east of Khuzestan province, using multi-year hydrograph analysis. The stage-discharge data from several consecutive years has been analyzed to determine the recession coefficients, the fraction of quick flow and base flow, and to identification the hydrogeological charactristics of the aquifers that feeding the springs. The results show that karst aquifers were formed in the Kuhe-safid anticline can exhibit different hydraulic behaviors. The analysis of recession coefficients reveals that the discharge of Barmejamal spring is controlling by two type of flow such as conduit flow and diffuse-matrix flow while the second is dominant. Whereas, for Poto spring the conduit flow with a threshold. In addition the hydrograph analysis show that the wet and droughts periods can considerably increase and decrease the Barmejamal spring aquifer storage, respectively. However, due to quick depletion, the wet periods will not increase the groundwater reserve of Poto spring aquifer. Consequently, in comparison to the Poto spring, the barmejamal spring is more reliable for water supply in dry and drought periods, because of highest amount and time of discharge. Furthermore, the results of this investigation reveal a scarce behavior for Poto spring discharge.

In recent years, Urmia Lake has dried up and its salinity has increased significantly. There are various reasons for this phenomenon. There is even a difference in the manner and rate of direct or indirect role of groundwater compared to surface water. Therefore, in this study, in order to identify the interaction of groundwater and surface water in the southeastern coast of the lake as the most important input to the surface waters of the lake, the temporal and spatial variations of groundwater flow were investigated. This study was carried out using the groundwater level map in May 2008, 2013 and 2016, as well as the groundwater transmissivity map and the rate of groundwater inflow and outflow using groundwater gradient changes. In addition, five cross sections including groundwater leveling and slope information at the desired time, as well as type of sediment deposits were used. In this study, it was found that groundwater inflow and outflow do not play an important role in aquifer volume in the region. Therefore, severe and local groundwater withdrawal due to over pumping, as well as changes in the volume and distribution of surface water resources, play a very important role in changing the direction and gradient of groundwater flows. There is a risk of saline water intrusion to the aquifers where there is a severe withdrawal in groundwater. In some areas, especially in the southern regions, the presence of underground dams of clay deposits with very high plasticity prevents the saline water intrusion into inland areas.

Evaluation of water quality is based on some chemical, physical, biological, and radiological characteristics of water and is of great importance for human utilities. One of the chemical characters of water is its salinity (total dissolved salts of water). It may have natural or antropogenic origin. A reason of high salinity of water resources is occurrence of evaporate layers in river watersheds. The aim of this research was investigation of the effect of geological formations on the water salinity of the Khar-Rud River basin. The total area of the basin is 5500 Km2 and 4130 Km2 of this area is located in Qazvin Province. The basin height is 1200-1680 m above sea level; it is located in the Central Iran Structural Zone. Field studies and physicochemical analysis were done in the the western reach of the basin (from the first tributary in Zanjan Province to Abe-Garm). The results show the Miocene rocks (lithology: mudstone with sandstone and evaporate intercalations) are the main source of the dissolved salts of river water. Water samples were taken in wet and dry seasons of the 2013-14 hydrologic year. The most dominant cation and anion in the river water samples are sodium and chlorine (respectively, Na-Cl type). Salinity significantly increases in the middle segment of the river; it gradually decreases eastward. The groundwater salinity is almost constant. It (associated with the ground water electrical conductivity) gradually decreases eastward. Thehighest salt content of the river water was measured in Dakhrajin, Arvan and Shurab salt mine (53, 45 and 47 g/l, respectively).

The Barme-e-Shoor permanent pond has formed on the Gachsaran evaporative formation in a closed water catchment area with standing water body during the whole year. The purpose of this study is to assess the pond water hydrogeochemical and quality properties during the months of March and August 2015. The water samples were taken starting from the main stream path on the Gachsaran Formation to its entrance point to the pond, and different locations and depths (1-3 m) inside the pond area to evaluate the concentration of the major elements and heavy metals during the two periods. The electrical conductivity (EC) of the water changes considerably from the value of 920 µ s/cm in the farthest point on the stream, to the value of 2030 µ s/cm at the stream entrance point to the pond, increasing to the maximum value of 4290 µ s/cm inside the pond in September 2015. The water type of the all surface, deep and inlet water samples in the both periods is the calcium sulfate due to the dissolution of gypsum along the stream path, inside the pond and also severe evaporation in the region. There is a good correlation between calcite, dolomite and gypsum saturation indexes versus sulfate concentration during the March, while in contrast and in the September, there is a low correlation between saturation Indices and sulfate concentration, which conforms again the evaporation effects on the pond water hydrochemistry during the high temperature season. The Gibbs diagram showed that the water-rock interaction in the pond and stream path is the main hydrochemical process affecting the water body. The heavy metals concentration abundance relation in the pond is Zn> Pb> Fe> As at 6 sampling locations. The Zn, As, Pb concentration of the whole samples are above the WHO standard ranges but lower than the ranges of FAO standards.

Erosion phenomenon and sediment transition is one the most complex hydrodynamics problems, so simply it is not possible the exact determination of its governing equations. Southeast basins of Urmia lake consist of high sediment production, because of haring special hydrologic conditions. The purpose of this research is to use and compare of imperialist competitive and genetic algorithms in estimating of daily sediment suspended load in Zarrineh rood river. For this aim, the daily discharge data and sediment suspended load of the sedimentary station in Zarrineh rood river wase used for 2007 and 2013 years. The results of two purposed methods were compared with actual sediment values. The results of validity of the simulation with ICA model show that RMSE in testing sample for ICA and GA algorithms are 237 and 229, respectively. Also, R2 of validity for ICA and GA has been 0. 889 and 0. 835, respectively. The results of this study indicate flexibility, ability and high accuracy of the ICA compared with genetic algorithm (GA) is good.

The geothermal source of the northern West of Sabalan, due to its presence in the active volcanoes of the present century, has a thermal source at a depth of several thousand meters and has a reservoir temperature of 150 ° C (approximately 240 ° C) and injection of magma under the layers below the reservoir In the category of convective geothermal systems, it has a high enthalpy that predominates in terms of the liquid phase relative to the vapor phase. In this study, wells Sampling and chemical composition and isotopic composition of these samples have been evaluated on the site of hydrothermal energy utilization in Sabalan North-West (NWS-1, NWS-3, NWS-4). Meshkinshahr water under the line of equilibrium in the range of immature water in the corner of the Mg and the fluids of the wells is close to the line of full equilibrium. The water (immature) has an approximate temperature of 250 ° C and fluids in the wells at about 280 ° C for a geothermal reservoir. According to the lithology of the region, the most important chemical method for the thermometry of hydrothermal waters in this area is the Na-K method, in the northwest sources of geometric measurements, the temperature is about 270-220, 140, 50, 30-30, 160-90 Centigrade degree. Tritium levels in these fluids indicate mixing with young groundwater. The range of δ D and δ 18O for the springs north of Sabalan are from 8 to 13, and 85 to 70, respectively. These are in the range of methionine water. According to the δ 13C data obtained from the analysis of CO2 collected from the region's fluids, it is likely that the CO2 originates from the Sabalan region of limestone.

Ajabashir plain is one of the active farming areas in the northwest of the country, which water needs are supplied from ground water resources. Groundwater often contains compounds of different origin. Determining the origin of water can be effective in managing and adopting measures to protect and exploit water resources in cases, where two or more simultaneous factors are likely to affect the increase of salts. In this research, the chemical composition of water, the processes governing its geochemistry and the sources of salinity of the aquifer of the Ajabshir plain aquifer have been evaluated. In order to distinguish hydrogeochemical characteristics of the aquifer, 27 samples were prepared from groundwater sources and analyzed. All evidence like certain ratios, hydrogeochemical graphs, saturation index and Compound Diagram of ionic ratios (Li+ / Cl-) vs. (Br-/ Cl-) indicate the groundwater samples which originate from different sources as different clusters. Based on the results of the present study, likely the saltwater intrusion from the Urmia lake highly likely would be rejected and other factors like cation exchange, saltwater intrusion from the evaporate brines, contemporary playas, and also weathering, leaching of salty-clayey layers from northwest of aquifer adherent to South East of Lake Urmia, and groundwater evaporation at the end of the plain could be the main causes regarding to used techniques. The used model was examined using 4 factors and 17 variables. The results indicated that these factors reported 89 % of the total amount of the subscription. From this amount, 46. 35% was explained by factor 1, 25. 65% by factor 2, 17% by factor 3, and 11% by factor 4.

Ground water resources management is of particular importance in arid and semi-arid areas. In this research, groundwater droughts in Shahrekord plain were investigated using GRI index. For this purpose, monthly water level measured in 32 piezometric wells in Shahrekord plain during the 31 year period (1984-1394) were used. In order to predict the GRI index values in Shahrekord plain for the next months, the first, second and third-order Markov chain models were used and the performance of these models were evaluated based on contingency table method. After forming the contingency table for the results of first, second and third-order Markov chain models, the values of CSI, POD and FAR statistics were calculated. The results showed that the Markov chain method had good accuracy in prediction of GRI values for the next 1, 2 and 3 months, so it can be used for forecasting groundwater drought in Shahrekord plain. In general, the severe droughts that have occurred in recent years due to reduce atmospheric precipitation, along with the overexploitation of groundwater have caused the severe decline in groundwater levels, which leads to groundwater quality degradation and land subsidence in the Shahrekord plain.

Prediction of groundwater level fluctuations is an essential for planning in arid and semi-arid regions. In this study, artificial neural network models, ARIMA time series and multivariate linear regression models were used to predict groundwater fluctuations of two piezometers located in Kerman plain. In order to achieve this goal, the depth of groundwater of the monthly piezometers was used during the years 2002-2013. The results of studying different models of ARIMA model showed that the ARIMA (0, 1, 1) and (2, 0, 2) for south Baghin piezometer and ARIMA (1, 1, 1) and (2, 0, 0) for Airport areas piezometer are the best-fit time series model with the data. In the model of MLP and RBF artificial neural network, MLP with 2 and 4 layers of hidden and RBF with 8 and 10 hidden layers for southern Baghin piezometers and the airport areas have the best fit with the data. In multivariate linear regression modeling, for each of the two piezometers, the best correlations of the multivariable linear regression model show that the multivariate linear regression relationship of groundwater depth of the current month is a function of groundwater depth of one month prior; in other words, the depth of water the ground water level has the highest dependence on groundwater depth of its prior month. The results showed that prediction of groundwater depth by multivariate linear regression model is better than Neural Network and ARIMA model.

Excessive population growth over the past three decades, limited surface water resources, agricultural, industrial, urban activities and excessive exploitation of aquifers have caused irreparable damage to Iran''s water resources regarding quality and quantity. To prevent the continuation of quantitative and qualitative decline, management of exploitation and protection of groundwater should be the basis of planning in the country. Groundwater management requires an adequate understanding of the aquifer system and the use of a tool that can simulate the response to the various quantitative and qualitative stresses of the aquifer in the current and future conditions. In this regard, by using the model, real conditions in nature can be simulated with good accuracy and achieved to acceptable results. The study area of Gamasiab is located in Sahne-Bisotun plain in the northeast of Kermanshah province. In this area, only one case investigated in a small part of the aquifer. In this study, the status of the aquifer and the relationship between surface and groundwater in the entire aquifer zone of Sahneh-Bistoon plain simulated with the use of the MODFLOW 2000 code, the GMS v10 software. The results of the model show that the water budget of Sahneh-Bisotun plain is negative in the year 88-87 and is 22. 81 million cubic meters per year. The river is the main factor that recharges the aquifer, which is 248. 8 million cubic meters per year, and pumping from water wells is the most crucial factor in the drainage of aquifers, which is 36. 4 million cubic meters per year. The results of the model show that the Gamasiab River recharges the aquifer in two reaches and drains the aquifer in other reaches. The river drains 15. 55 million cubic meters of water per year from the aquifer.

The rapid increase in the water demand has led to large-scale groundwater developments in Ardabil plain, and intense extraction of groundwater has caused water table to decline as much as 12 m during the past 25 years. Optimizing the groundwater extraction in order to prevent declination of the water table and the possible compensation of the reduction in the aquifer storage are the main purposes of this dissertation. In this study, according to the modeling protocol, at first the conceptual model of Ardabil plain aquifer has been designed. For this purpose, a geodatabase consist of qualitative and quantitative data has been created. Then Kriging and fuzzy logic methods have been applied to create different kinds of zoning maps. After determining of the aquifer geometry, input and output parameters, groundwater flow system and hydraulic parameters, Modflow 2005 code was used by the PMWIN8 software for modeling the groundwater flow in Ardabil plain aquifer. After the modeling, based on the declination of the water table, the Ardabil plain aquifer has been divided to 15 zones. Then, the optimized values of the permissible extraction have been estimated using the PEST software. Based on the obtained results to balance the water table of Ardabil aquifer, the highest and the least exploitation should be at the east and center of the plain respectively.