abdol hossein hoorfar

The groundwater level decline has caused an environmental issue in most of the Iranian aquifers. In this regard, aquifer storage and recovery (ASR) system can be used as a solution. On the other hand, the huge volume of treated wastewater in big cities can be used as a water source for aquifer storage purpose. In this study, the treated wastewater, soil and groundwater quality have been investigated through the unsaturated-saturated porous media. An experimental model, as L-shaped, has been designed using PVC pipe material with a diameter of 200 mm and a length of 15 m (2.5 m vertical and 12.5 m horizontal). The wastewater used in this research was obtained from the outlet of the sewage treatment plant in the south of Tehran. In order to avoid changes in the quality of wastewater during storage in the tank, it was tried to a regular change the treated wastewater in short intervals. After the initial investigations, a zone situated in center of in the Feshafuye plain, has been selected for treated wastewater injection. Then the required soil for laboratory setup has been collected for tis area. In this regard, firstly, the surface layer soil was removed, then the subsurface soil was transferred to the laboratory for the experimental setup. The required inflow water for this setup was taken from the aquifer of the same area and was changed regularly in order to establish the maximum real conditions. During this study, treated wastewater have been sampled and analyzed at 12 points along the flow path for 60 days. The results showed that the nitrate concentration decreased to less than 0.5 ppm after 7 m and microbial pollutants, total coliform and E. coli had been removed in a 100-cc sample after 6 m. In terms of salinity, the treated wastewater and soil quality have been improved from an EC of 4 to 3.3 dS/m. The BOD and COD have decreased by 81% and 87%, respectively. Due to improvement of treated wastewater quality through the unsaturated- saturated porous media, the ASR system can be implemented as a solution to prevent the groundwater level decline.

Herein, the stability of the Zarandieh-Saveh aquifer was investigated, based on field monitoring data and simulation. It was simulated involving GMS software and calibrated and vitrificated in both steady-state and unsteady-state conditions, for 84 monthly steps(2012 to 2022). The values of Aquifer Sustainability(AS) and Groundwater Dependence(DG) indices calculated equal to 31.1% and 0.78%, respectively, which shows the aquifer is in a critical condition and the region is highly dependent on groundwater. According to the Groundwater Damping Index(GDR), with the continuation of the present extraction process, the aquifer will be completely discharged in the next 53 years. The scenario of 20% reduction in annual extraction as the most appropriate scenario will result a rise equal 4 meters in ten years. The operation of the seasonal floods artificial recharging project has had a significant effect on improving the level of this aquifer. The interbasin transfer and recharging scenario of Al-Ghadir Dam overflow have a positive and significant effect on the groundwater level equal to 0.75 meters per year. Based on the results, the parameters and factors affecting the balancing of the Zarandieh aquifer, the first priority is to reduce the exploitation and then increase of recharging from the Al-Ghadir dam overflow site, which can have significant effects on the stability of this aquifer.

The Hargreaves-Samani method of estimating reference evapotranspiration (ETo) has been recommended by irrigation and drainage paper No.56 of the Food and Agricultural Organization of the United Nations (FAO)  in the situations that weather data are missing. since the method requires just measured temperature, the it has been used in several studies over the past decades. FAO paper No. 56 and other investigations has mentioned that Hargreaves-Samani method is an overestimating method in humid cliamtes. Hence, the method has been calibrated for different site and situations. This issue made the purpose of the current study. In this study, the history of the development of Hargreaves-Samani method has been reviewed. Thus, an equation for adjusting humidity condition is discussed. To compare the goodness of models,  ETo was calculated based on 3 different methods 1) Hargreaves-Samani method 2) Allen modified method of Hargreaves-Samani, and 3) the modified method of Hargreaves-Samani based on relative humidity. Also ETo was calculated according to FAO Penman-Montith method as a control estimation. The values were calculated for monthly weather reports of 4,169 stations from CLIMWAT v2.0 all around the world. The results showed that the Hargreaves-Samani’s method has a weakness of estimation under extreme conditions. Interestingly, the corrected method improved precision of the estimations especially in arid and semi-arid locations.

Accurate estimation of pollution decay coefficient is due to its effect on the oxygen consumption of the river’s solution of important issue, in managing the quality of water resources. The main purpose of this paper is to determine the decay factor of two rivers of Iran, named Talar and Babolrood Rivers. It has been done by measuring the field and elucidating the common empirical equations in two seasons of spring and summer. The qualitative parameters including DO, BOD, pH, EC, nitrate, phosphate and temperature in Talar River were measured in 5 sections of a total length of 4 km long, and in Babolrood River in 3 sections at a total length of 2.8 km, in May and August 2018. Then the decomposition coefficient was estimated using Streeter-Phelps Analytic Model. DO and BOD values were also analyzed in both spring and summer seasons. Based on the results in both case studies, the decay rate in summer was more than spring. The decay rate in Talar River was calculated equal to 1.57 in spring and 6.11 in summer, and in Babolrood, spring was 1.2 and in the summer was 8.34 (1/ day). Also, based on the slope changes, the dissolved oxygen content in both rivers increased in spring and decreased in the summer. In Talar River the BOD was equal to 4.34, in spring and 7.44 mg per liter in summer, and in Babolrood River in spring was equal to 2.5 and in the summer equal to 3.2 mg per liter.

Today, groundwater contamination has become a major environmental issue around the world. Petroleum products affect groundwater quality at many sites across the country. It mainly results from leaking or seeping of products from storage tanks or transferring pipes. These products are typically multicomponent organic mixtures composed of chemicals with varying degrees of water solubility. Many of the petroleum products are amenable to biological degradation in the aqueous phase by naturally occurring microorganisms in the subsurface. To create and maintain conditions that are conductive to microbial activity within the contaminated aqueous-phase is the main focus of this research. BTEX was selected as the petroleum contaminant to be used in a laboratory experiment. A two-dimensional sand tank was built and BTEX was injected into the sand at top of the unsaturated zone. In order to simulate the behaviour of the bacteria and to predict the long-term remediation program, RT3D model with double Monod algorithm was selected. The comparison of the observed data in laboratory experiment with simulated results showed that the calibrated model can simulate the BTEX movement and biodegradation, satisfactory. Using the calibrated model indicated that complete remediation would occur after three months with biodegradation and 27 months without biodegradation. This proved that how important is the biodegradation in long-term remediation projects. In addition, the proposed methodology in this research for isolating the bacteria and remediation was successful and can be proposed to be implemented in larger scale.

since the agricultural sector in IRAN is the largest consumer of water resources , it is important to determine the economic value and financial efficiency of farmers as an economic good. The purpose of this paper is to determine the economic value of water and financial efficiency of farmers in Khondab plain, Markazi Province of IRAN. In this study, the performance of four crops including wheat, barley, alfalfa and corn were calculated, involving a newly developed mathematical model. The average price of agricultural water has been determined using three weighting methods based on the volume of water, the cultivated area and the income, for each plant. Among these method the method based on volume of water, has selected as the most appropriate method. Financial efficiency for the all three modes, free water, 10% of the calculated price and the actual price of water from the farmer were calculated. Results show that financial efficiency is sensitive to changes in income and it is more sensitive that changes in costs. Irrigation efficiency and financial efficiency are not similar in all cases.

Local differences in fluid density have important role in contaminant transport. Study of variable-density flow and solute transport in fractured porous media is necessary to figure out phenomena like contaminant transport of high density. In this research, the effect of permeability and molecular diffusion, respectively as a characteristic of porous medium and solute, on convective flow in fractured porous media has been studied using numerical modeling by FRAC3DVS/Hydro Geosphere (HGS) model. Conceptual model has been considered as a porous medium contained regular vertical and horizontal fractures. Four scenarios of different porous matrix permeability and free-solution diffusion coefficients have been taken account into the modelling process. The results indicated various patterns of solute transport in fractured porous medium in four different scenarios. So that, in the first one with high molecular diffusion coefficient, the solute is diffused into porous matrix from fractures symmetrically. While in the second scenario, with low molecular diffusion coefficient, the solute is transported in deeper depth and is diffused into porous matrix from fractures in an uprising way, in opposite direction of the contaminant entrance direction. In the next scenario, the more porous matrix permeability, the more convective flow velocity and solute transport in porous matrix. Finally, less differences between the matrix and fracture permeability in the last scenario leads to decrease of the fracture effects on the convective flow pattern, so that flow pattern in the fractured porous medium becomes similar to flow pattern in the homogenous porous medium.

Drought duration is defined from different viewpoints. Estimation methods of drought duration return period are different in terms of drought duration definition. This paper is aimed to perform six estimation methods of drought duration return period at Kermanshah station, as a case study. The standardized precipitation index (SPI) is used to monitor drought based on historical and synthetic series of total precipitation data in annual and monthly timescales. Probability distribution of drought duration was analyzed for time series of SPI. Different methods for estimating return period of drought duration on historical and synthetic time series of SPI were applied. Findings answered two main questions: a) if the length of historical record was enough to estimate drought return period at the station of interest? b) If the obtained return periods based on different methods have enough conformity with empirically obtained return period? Results are discussed in details in this paper.