JOURNAL OF ENVIRONMENT AND WATER ENGINEERING
Year:2019 | Volume:4 | Issue:4 |Papers Count:8

Hydrological droughts reduce groundwater and surface waters. The purpose of the present study was to analyze the minimum regional flow frequency in parts of the northern Karun basin in Chaharmahal and Bakhtiari province. For this purpose, 11 hydrometric stations were used. For the minimum flow estimation, 15 different physiographic, climatic and hydrological features of the basin were used in. At first, hydrometric stations were divided into two homogeneous groups using cluster analysis method. Then, using principal component analysis (PCA), the most important features were selected for each region among the 15 physiographic, climatic and hydrological characteristics. Finally, the models for estimating the minimum flow of each region were developed using stepwise regression method in return periods of 2, 10, 25 and 50 years. The results showed that the characteristics of the basin area with a weight of 0. 347, elongation coefficient with a weight of 0. 389, a length of the basin with a weight of 0. 326 and a coefficient of roundness with a weight of 0. 326 were the most important features in the estimation of minimum flow. In general, all regression-logarithmic models in the two regions for all return periods with a coefficient of greater than 0. 96 were considered to have a good performance for minimum flow estimation.

The purpose of this study was to remove nitrate ion using montmorillonites nanoclay modified with octa decy lamine functional group. In this study, nanoclay was first modified using octa decyl amine and the size and surface properties of this modified nanoparticle was investigated by scanning electron microscopy (SEM) and X-ray diffraction spectrum (XRD). In the next step, the nitrate ion adsorption process was investigated using adsorption model and by examining the effect of parameters of contact time, nitrate ion concentration, pH, and, adsorbent dosage on nitrate removal. Adsorption rate was evaluated by atomic absorption spectroscopy. The results showed that the correction of the nanoclay surface modified by the amine group increased the interlayer spacing from 7. 58 to 22. 91  A. The size of the modified nanoparticles was about 80-100 nm, which increased the active adsorbing sites by increasing nanoadsorbent surface. In the study of adsorption of nitrate ions, the maximum adsorption achieved at pH 5, the initial concentration of 100 mg/l, the contact time of 40 min, and 0. 7 g of nanoadsorbent. Studing the equilibrium isotherms, it was found that the adsorption process follows Langmuir and Freundlich isotherms. The kinetics of this process are consistent with the second-order kinetic model.

In water resources management, there is a critical need to the prediction of the amount of inflow into the water supply system in order to be aware of future conditions and planning for optimal allocation of water resources to different sectors such as drinking, agriculture and. The aim of this study is to forecasting the monthly inflow to the Gorgan dam for future. To this aim, the data of the Qazaghli station with a 47-years history period and three Time series, neural network and Support vector machine models used for prediction. According to the obtained results, the ARIMA (1, 0, 0) (1, 0, 1) was found to be the premier parsimonious time series model based on the Akaike and Schwarz criteria. Moreover, The ANN model with 2 input and 10 neurons tuning and the SVM model with one input were the best performing models. Finally, according to the obtained results and evaluation criteria, the SVM model has the best efficacy in comparison with two other methods. The RMSE and AARE was 5. 31 and 1. 07 for SVM model, respectively; 9. 88 and 2. 78 for neural network, respectively and 8. 84 and 1. 07 has been obtained for Time Series model, respectively. Based on the results of this research, the best model to predict the monthly discharge input to the Gorgan dam was SVM.

Nowadays, drought is known as one of the environmental phenomena that has important impact on water quality. The aim of this study was to obtain a relationship between drought and water quality in Zayande-Roud watershed. With respect to the impact of drought on water quality and also determining the type of water and its relationship with environmental factors, in this study, chemical characteristics of water were investigated using AqQa software. Then, chemical type of water resources and its relationship between drought and water quality was determined. The study area was Zayande-Roud River that has five hydrometric stations with 34 years common data. Two stations were located before dam and three stations after dam. In this period, using drought indices (SPI and RDI), dry and wet years were separated from each other, then maximum common dry and wet years were determined in five stations. Then, water quality data were compared in dry and wet years. Based on the results obtained, with the occurrence of drought, the concentration of ions in water has increased and in wet years the concentration of ions in water has improved. As example in Eskandari station, magnesium ion has increased by about 37% in dry years and the rate of sulfate ion in Pol-e-Zaman Khan station has increased by 56% in dry years. Water type in each station was sodium bicarbonate that can be related to geological factors.

Proper and sustainable use of water and soil resources is on the agenda of executive agencies. Therefore, optimum design of drainage systems is very important. Effective porosity and soil hydraulic conductivity coefficients should be determined with acceptable precision. In addition, it is essential to evaluate the unsteady underground drainage equations under farm conditions. This research was carried out in underground drainage system in Shadegan Plain. The effective porosity and soil hydraulic conductivity were determined by measuring the time, the height of water table, and the discharge outlet from the lateral drain. Moreover, through inverse solving, the soil effective porosity and hydraulic conductivity in Shadegan Plain were estimated. The mean effective porosity calculated using Taylor method was 0. 0117 (dimensionless) and the mean soil hydraulic conductivity calculated by Skaggs method was 0. 31 m/d. In following, using measured data of time and height of water table and also prevalent unsteady underground equations, the drain intervals were estimated. The calculated distance was analyzed with 50 (m) measured distance. The evaluations showed that the Glover, Dumm, Van Schilfgard, Bouwer and Van Schilfgard, modified Glover and Hammad equations have priority repectively. In using unsteady drain equations, it should be noted that it is not possible to prioritize specific equation. On the other hand, for each region, these equations must be evaluated individually and the best equation must be selected.

Soil contamination with cadmium and lead released from vehicles is a serious environmental problem. Lead as a result of using leaded petrol fuels and cadmium from the car tire are introduced into the environment through vehicle depreciation and traffic. This study aimed at investigating the spatial distribution of heavy metals such as Pb and Cd at the roadside soils of Zabol-Zahedan route. For this purpose, 252 soil samples were taken from a depth of 0-20 cm and the concentration of total lead and cadmium metals, physicochemical properties of soil including pH, EC, and organic matter were measured. The contamination assessment of soil was performed through using enrichment factor and geoaccumulation index. The spatial distribution of Pb and Cd concentration was mapped using kriging method. The mean concentration of Pb at 0, 50 and 100 meters was 2. 12, 2. 03, and 2 mg/kg, respectively, which is less than the global mean (25 mg/kg) for this metal, and for Cd, it was 0. 21, 0. 21, and 0. 20 mg/kg respectively, which was lower than the global average (0. 53 mg/kg). The results of the geospatial analysis showed that both variables were anisotropic and the exponential model for lead and Gaussian model for Cd had the best fit. Interpolation map's analysis showed that Cd and Pb have geological and human origins. In fact, these metals naturally exist in soils, but human activity has caused the accumulation of these metals in the soil.

Temperature is one of the factors affecting plant growth. Hence, in this paper, future temperature trends in Abhar region affected by climate change during future periods was evaluated and compared with the period of observation. Plant yield in the future and different cultivation periods was later simulated and estimated through AquaCrop simulation model of plant yield. The study observation period was considered as 1986-2010 AD, near horizon 2011-2045, the average horizon 2046-2079 and 2080-2100 horizon in the current study. LARS-WG software was used in HadCM3 model and A2 scenario in order to downscale the results of general atmosphere circulation's simulation model. Furthermore, the scenario file was generated in this study. According to the results obtained, the highest yield wil be cultivated on May 26 with 46. 29 tons per hectare and the lowest yield will be produced on June 5 with 40. 6 tons per hectare. If we change the traditional cultivation time from May 15 to May 26, a growth of 0. 28 tons per hectare will be expected. The highest yield will be on May 15 in the future. Moreover, the sorghum's yield will decrease. Lesser photosynthesis during the shorter growing season and C4 photosynthetic system of this product could be involved in this yield loss.

In water disinfection and treatment, rapid detection and monitoring of pathogens such as bacteria and viruses, as important water quality indices, are of prime importance. On the other hand, continuous monitoring and detection of pathogens have encountered the problems such as low concentration of bacteria and viruses in water, low sensitivity of the conventional detection methods, complex sample matrices and insufficient selectivity of the conventional methods, and inability of these methods in fast and cheap detection and continuous monitoring of pathogens. These indicate the importance of considering new sciences and technologies in fabrication of biosensors in order to achieve higher sensitivity, response rapidity, and selectivity. In this paper, briefly, new nanoscience approach and application of nanostructured materials in design and fabrication of nanobiosensors in order to detecting and monitoring of bacteria and viruses in water have been introduced and some examples of the applications of nanobiosensors have been also presented.