نشریه زمین شناسی محیط زیست
پیاپی 49 (زمستان 1398)

Jajroud River is located in Pardis city in the east of Tehran. The purpose of this study is to determine the amount of water pollution in this river For this purpose, 15 samples of water were collected in early July 1397. Water samples were then analyzed to determine the concentrations of Fe, Cr, Cd, Zn, Pb, Cu, Co, Hg, As and Mn. The values ​​of cation and anion, TDS, pH, EC, COD, BOD, salinity, DO, NTU, gastrointestinal coliform and total coliform were measured in water samples. The reason for these measurements is to determine the quality of river water in terms of its physical and chemical variables. The average pH in surface water samples is 7.703, which indicates the alkaline nature of water samples. The high electrical conductivity of the Jajroud River is due to agricultural, horticultural and residential activities. High TDS indicates that the nitrate in the water is very high. Decreasing trend is the average concentration of the main cations in the water samples of Jajrud River as magnesium, potassium, sodium, calcium, and the order of the concentration of anions in surface water samples as chlorine, sulfate, phosphate, nitrate, bicarbonate. The result of ion distribution in the piper diagram indicates that the water type of anions is of sulfated type and is located in the chloride facies. And the type of water in sodium-potassium cations is in the magnesic facies.

In today's growing world that explosive population growth it has an endemic growth of residual and its specific contamination, the environmentalists' minds are concerned about the extent to which the material can endanger the environment, water, soil and air. The unhealthy disposal of solid waste on different organisms at different concentrations and pollution intensities will produce different effects. The purpose of this study, environmental assessment Yazd solid waste landfill for this purpose, environmental sampling of the environmental elements of the current landfill site and determine the composition of municipal solid waste was done. The results of the well water analysis showed a slightly higher concentration of some of the investigated elements in the lower reaches of the burial site than the World Health Organization's (2008) standard for drinking. Soil analysis results showed a slight increase in the concentration of some elements in and near the landfill (in the direction of the slope of the layers), compared to the Canadian standard (2004) for agriculture. The analysis of the well water in the control and sample samples was lower (far from the burial site), and the concentration of the elements was close to the normal range. In relation to the analysis of leachate, the parameters are not consistent with the irrigation and agricultural standards of the Water Pollution Control Agency (2011). Finally, it can be said that the results of the analyzes did not show the widespread and critical effects of burial on the environment, especially the urban environment.

The precision of groundwater level estimation is a function of the density, location and accuracy of the wells. As the number of piezometric wells increase, the precision of surface estimation is improved, but digging and maintaining piezometric wells is always costly and time consuming. The main objective of this research is to minimize the number of piezometric wells and to identify valuable wells for precise prediction of groundwater level. The main innovation of this research is the inclusion of spatial and temporal information in optimizing the number of wells. This research was conducted in three main phases: 1) Obtaining information of 75 piezometric wells of Tabriz plain and exploratory spatial data analysis (ESDA), 2) Implementation of the ant colony optimization algorithm in combination with the simple kriging method and the identification of wells in each year, 3) Calculation of the final value of wells based on number of times each well was present in the calculations for 2014-2017. The results show that of the 75 wells per month, an average of 18 wells adds limited information to the calculations. Of these 75 wells, only two wells in none of the 36-month calculations were considered as valuable wells, and 15 wells have a relative value less than 11 percent. Therefore, the number of piezometric wells can be reduced 20% (15 wells), without a sensible data loss in the estimation of groundwater levels in the area. The results show that using temporal information of wells and proposed method, valuable wells can be identified and, by saving time and cost, to some extent reached the precision of the initial level.

This study represents the application of a generalized likelihood uncertainty estimation (GLUE) technique for automatic calibration of the well-known Hydrologic Engineering Center-Hydrologic Modelling System (HEC-HMS) model. For this purpose, the GLUE method was used in calibration of the HEC-HMS model built for Dez Dam basin located in south-west of Iran. From the three selected events, first event was used for calibration and all events were used for uncertainty and sensitivity analysis using GLUE approach. Model calibration showed that the developed model is a suitable model for simulation of flood with R2 and Nash-Sutcliffe Efficiency of 0.9 and 0.887, respectively. Sensitivity analysis of the model based on the four parameters of the Green Ampt method indicated that model does not show the same sensitivity on the same parameter in different events. For instance, saturated hydraulic conductivity has the greatest influence on the model of event 1 and model of event 3 is more sensitive to saturation suction at the wetting front and porosity. Uncertainty analysis using posterior distribution describes the uncertainty of estimation after taking into account information provided by the various flood events. Overall, the GLUE analysis showed that there is a significant uncertainty associated with hydrological modelling that is due to multiple sources of errors. Also, this method can be used for calibration of hydrological models like HEC-HMS

In this study, a range of 50 km radius of Semirom city for the seismotectonic and seismicity evaluataion is selected. A list of earthquakes happening in the area is prepared including 156 instrumental earthquakes with magnitudes of the unit Mw ≥ 3 since 1973 to 2018. Based on obtained results, due to the location of the study area in the Zagros Zone, seismotectonical mechanisms and structures of Semirom city influenced by this zone. Also, most earthquakes in the range of radius 50 km of Semirom region under the action of the Zagros reverse faults. The seismicity of the studied area from the north and northeast to the southwest is increased. Finally, by Kijko (2003) method, seismicity parameters, the annual rate of occurance and earthquake return possiblility for studied area is calculated.

The response of underground habitats to loading from a surface explosion is a major issue in environmental Protection. Underground habitats are often found in small and large caves, as well as in the form of groundwater aquifers under mountain ranges and in various parts of the globe. So far, many studies have been carried out on various parameters such as ground response, structure response, field experiments, etc. However, there are still many unknown and vague aspects of the explosion and its impact on the soil and structure environment. In this study, the effect of soil layering on the safety of an underground habitat has been investigated in terms of acceleration value and pressure transfer on it. Autodine software has been used to model the underground habitat, and two Lagrangian and Eulerian environments have been considered. The chosen explosive charge in this study is 52.16 kg of TNT, and the data is recorded using the gauges enclosed in the model. The results show that the presence of a sandy clay layer in the surface has transferd the more pressure to the next layer and led to the deterioration of the situation. Also, the presence of dry sand clay under the sand layer has increased the acceleration value.