مجله هیدروژیولوژی
سال یکم شماره 2 (زمستان 1395)

Porous media such as groundwater aquifers, oil and gas reservoirs have a large amount of heterogeneity. Modeling of flow and transport in such environments is based on a survey of the properties of porous media. In this paper, fractal permeability of porous media has been estimated using the Monte Carlo simulation. Using the results of previous studies and measurements on several sandstone samples, such as porosity, fractal dimension, fractal property and intrinsic permeability, using a Monte Carlo probabilistic model and a set of random numbers between 0 and 1 and pore diameter measurement, the sandstone permeability was determined. Finally the simulated and measured values of samples sandstone permeability were compared. Monte Carlo simulation results show that without any need for empirical coefficients, domain discretization with only a few laboratories measured parameters one can reasonably determine the fractal permeability of porous media. Measured and calculated permeability correlations are matched 83 percent.

In most regions of Iran the requisite water for populations and industry are supplied by groundwater resources. Drought is an important factor, which effects groundwater quality. Demand for groundwater resources is increasing in Qurveh - Dehgolan plain due to its position and limited access to surface water resources. In this research, the effects of drought on water quality of wells in Qurveh – Dehgolan studied. Water quality data in 38 wells for 21 years (1992 to 2013) used to define dry and wet period the Standardized Precipitation Index (SPI) for 3, 6, 12 and 24 months’ time scales calculated. Using Mann-Kendall tests, the trend of ground water quality parameters investigated and the relation between climatological drought and groundwater quality parameters calculated using correlation coefficients. Study of correlation coefficients between quality parameters and SPI showed in 22.2% of cases, drought effected on groundwater quality (at 95% level). Correlation coefficients were positive in some wells and were negative in other wells. Also in most quality parameters, with increasing of SPI time scale, the rate of correlation was increased. The results of Mann-Kendall test showed the most parameters of water quality had increasing trend and Cl-, HCO3- and Mg2 had negative trend in 60.53%, 60.53%, and 52.63% of wells respectively. In addition, CO32- had not trend in any wells. Zoning map of water quality showed that most reduction of ground water quality was happened in eastern part of plain, because the ground water level downfall in mentioned part was higher than other parts.

Estimation of hydrodynamic parameters of aquifer is one of the important problems of groundwater resources management. There are many different approaches to estimate the hydrodynamic parameters of aquifer and among them the application of geoelectrical surveys is the most developed one. In this contest forty four vertical electrical soundings have been used to evaluate the hydraulic properties of aquifer in Golgir plain, Khuzestan. The thickness, lateral extent and resistivity of the aquifer layers were determined by the electrical survey and borehole logs. Transmissivity values were inferred using the empirical relationship between hydraulic conductivity and formation factor with correlation coefficient of 0.75. Results show highly variable thickness of the main aquifer in the study area. High values of transmissivity, specific yield obtained in eastern plain part is due to exist erosional course sediment from Asmari limestone formation. Also, Lower average values of porosity were estimated in eastern parts. Finally, geological and hydraulic parameters maps of Golgir aquifer have been produced. Overall results indicate useful estimation of Hydraulic parameters that was used by geoelectric method and they can be used in making decision and future drilling program in the study area.

Quality of recorded information in a monitoring network plays an important role in sustainable design and operation of water resources systems. For an optimal monitoring network design, they should be evaluated periodically based on the information needs and future water resources development plans. In this study, regional values of groundwater quality monitoring network stations in Khanmirza plain were investigated using the discrete entropy theory. Discrete entropy can overcome the limitations regarding data normality assumption in past research. Several entropy parameters such as marginal entropy, joint entropy, information send and received by each station and transinformation index between stations, were calculated to identify essential stations and poor regions based on the amount of information exchanges. Sensitive analysis to number of discrete intervals shows that the entropy indices are sensitive to change of interval length, but the ranks of stations appear to be less sensitive. Validation result confirms that the entropy has a good performance in quantifying the regional values of sampling wells in a monitoring network and comparison with the correlation coefficient of information between stations shows that this coefficient can be used for determining the essential and unnecessary stations in the region.

Construction of drainage system under concrete lined canals for uplift reduction, prevention from failure, heaving or creation of crack in lining is necessary when ground water level is high. Drains lead to reduce the uplift and improve the canal stability. Proper location of these drains can have significant effect on uplift reduction. The purpose of this study is numerical investigation of drains for uplift reduction, which can help to canal durability and life. For this purpose, the SEEP/W software was implemented that is a subgroup of Geo-studio software. Results showed that application of drains under the canal bed can decease/neglect improper effect of ground water level. Installation of drains under the edges of canal bed or in deep depth, causes for higher decreasing in ground water depth, and more reduction in uplift pressure. Drains depth is not constant and increase with increasing ground water level or reduction in drains diameter and vice versa. Linear and nonlinear regression equations were obtained for estimation of uplift pressure that designers can use them. Comparison between numerical results and experimental observations were carried out and showed good agreement.

Among all types of mass movements, landslide is the most common which causes costly damages to landscapes and human lives. In Iran's northern watersheds, landslide events are observed because of high amount of rainfall, inappropriate landuse managements, and sensitive lithology. Damages caused by landslides can be doubled if they happen in a watershed which is located in upper part of a dam because the moved soil sediments in reservoir of the dam and fills its capacity. In this study, which aims landslide susceptibility modeling and mapping in Taleghan watershed, AHP method was used in order to determine each factor's weigh in causing landslide and FUZZY approach was applied in GIS environment to overlay the fuzzy factor maps. In order to choose the most suitable model, different models were applied through 6 scenarios. Output of each scenario was compared with observed landslides and the cumulative overlap area curves were plotted for each scenario. The model used in scenario number 6, which had the most increasing rate (0.237) in the curve and meanwhile had the least area under curve (0.3) was chosen as the ideal model for landslide susceptibility mapping in the area. In the process of this research slope curvature, which is lacked in many studies on watersheds in the country, has been considered as a causative factor.

Because the surface water resources in many parts of the country is limited, Groundwater as the most appropriate available resource to supply water needs to be considered. Identifying the areas with good potential for groundwater recharge has become the most important factor for filling. The potential for groundwater recharge from surface features, below ground level and depends on meteorological parameters. This research has been tried to areas with the potential for groundwater recharge Madian River basin with weighted overlay index analysis (WIOA) to be determined. This method, Integrate local maps of groundwater, geology, geomorphology, slope, drainage density, land use, rainfall, altitude and soil were discussed. The Groundwater has very good potential, good, Moderate to good, Moderate and Less became clear. The percent 66.55 of the study area is in the category of very good, good and, moderate to good groundwater recharge. Results wells were validated based on the output level that reflects the results of the work coincides with the water level was observed

The main water resource in arid and semi-arid regions is groundwater. Therefore, its study is important. The purpose of this study was groundwater level forecasting in Tassuj-Azarbaijan Plain in the future by artificial neural networks. Used data was from October 2002 to September 2013 (11 years). After determining boundary of Tassuj plain, water and observation wells where located out of boundary, was deleted. Then by Tissen method, polygons of observation wells were determined and input and output water into each polygon through rainfall, evaporatin and water wells were calculated. Finally, by designing 4 different architectures, the best network to forecast groundwater level was determined. Multilayer perceptron with back propagation error algorithm was used to simulate and forecate groundwater level. The results showed, considering monthly air temperature as input data in networks, was confused them. Network with 1 to 5 time lags in input data was the best. On the best network, values between calculated and observed data in 10 observation wells were greater than 90% and RMSE values were less than 80 cm. Finally, groundwater level was predicted for 24 next months (from October 2013 to September 2015). On the forecasting data, falling the groundwater level will be continued in the 24 next months as much as 1.3m.