فهرست مطالب حسین ربانیها

Wetlands play an essential role in the ecosystem and have a significant impact on people's lives, so the restoration of destroyed wetlands is vital. With the lack of water sources, municipal and industrial wastewater can be used as alternative water sources for various purposes. Due to the presence of contamination in wastewater, the use of wastewater carries risks depending on which purpose it is used for. In this study, the risk of using Alborz Industrial Town treated wastewater in Qazvin province to restore Allahabad Wetland has been investigated. First, by visiting the project's origin, route, and destination and holding numerous meetings with experts involved in the project, influential factors were identified within the scope of the project. Then, an integrated hierarchical structure was created to express these factors. This structure starts from the initial nodes which are the quality of the effluent and leads to the final node. Using the water quality data of the Alborz Industrial Town treatment plant that were collected in the year of study and collecting the opinion of 20 experts in the form of a questionnaire in order to evaluate each node, the risk of the wastewater transfer project to Allahabad Wetland was calculated using the Bayesian network method. The academic version of GeNIe software was used to calculate the risk using the Bayesian network method. The results showed that among the middle nodes of the risk structure, the lowest and highest values are related to the nodes of heavy metals in the health environment risk subgroup and the increase of implementation costs in the economic subgroup. Despite the fact that the effluent quality is within standard limits in most parameters, environmental, cultural, social, economic and technical health risks are equal to 44, 47, 50 and 49%, respectively. The total risk of the project, which is the result of four risks, was calculated as 49%. According to the acceptable quality of wastewater and the calculated risks, the nodes and weights of other economic, technical and social sectors have influenced the final risk. Therefore, to reduce the risk of the project, these parts should be examined. The technical and economic part of the project has more potential for project failure. Before implementing the project, various environmental, social, technical, and economic dimensions should be carefully examined and the possibility of creating risk should be minimized. To reduce the risk of the wastewater transfer project to the wetland, pollutants such as heavy metals must first be removed from the wastewater, and social tensions should be prevented by increasing the awareness of the people of the region and also by allocating water quotas. Allahabad Wetland plays an important role in the ecosystem and people livelihood of the region, and with a more detailed examination of the dimensions of the plan and risk reduction in the four environmental, social, economic, and technical sectors, the implementation of the wastewater transfer project to Allah Abad Wetland can be effective in its restoration.

Drip irrigation systems are a proper technique to supply water for plants in the root zone. The management of this method relies on the science of water distribution in the volume of wet soil. Simulation models can be used to obtain this valuable knowledge. In this study, simulation of sand column in the root zone of apple tree under drip irrigation system was done to determine the optimal depth of the sand column in three various soil textures to investigate how water is uptake by the roots, water consumption, evaporation rate and deep penetration using The HYDRUS-2D model was examined. The results of this study showed that in the loam soil texture when the depth of the sand column is in the range of 10-15 cm and in the silty loam soil texture of the sand column to a depth of 5 to 10 cm, the rate of infiltration, water consumption and evaporation will be significantly less than the maximum so that the rate of deep penetration in the silty loam soil texture has decreased by 55% and in the loam soil texture by 35% compared to the maximum state. and finally, the studied scenarios showed that in sandy loam soil texture, due to the lightness of soil texture, the use of sand columns will not create an improving situation.

One of the threating factors to freshwater resources is the advancement of saline water and intrusion into the groundwater aquifer. This problem occurs in coastal zones and desert margins and reduces freshwater quality. Evaporation from the soil surface and the water table depth are factors affecting the salinity and salt distribution in the saturated and unsaturated zones. HYDRUS and the accompanying software package provide numerical models used to simulate the movement of water, solute and heat in a porous medium for saturated and unsaturated conditions. According to the existing reports on the ability of the HYDRUS model to simulate moisture and salinity, using it can help decide and consider how to prevent the salinity advancement.

In this research, the advance of saline water with a concentration of 20 dS/m and a level of 25 cm towards freshwater with a concentration of 1 dS/m and a level of 10 cm in the domain of 360×70 cm is considered. Different scenarios were examined to prevent the progression of salinity using a validated model. The studied scenarios include inceptor pipe drainage, inceptor open drainage and subsurface barrier which were simulated using the HYDRUS-2D model. The parameter of the equations governing water flow and solute transport were estimated using observed moisture and salinity data and inverse solution tools in the HYDRUS-2D model. pipe and open drainage were considered at three distances of 270,180 and 90 cm from the freshwater reservoir and two depths of 15 and 5 cm from the impermeable layer. The effect of the subsurface dam on preventing the advance of saline water at three depths of 55, 65 and 70 were investigated.

Different scenarios of different drainage locations have been simulated to study salinity distribution and water table after 6 months. Regarding the location of the drainage site, three factors are important that have been studied: 1- The amount of water and salt outflow from the drainage 2- Controlling and preventing the advance of salinity 3- Its effect on the entry and exit of water from the freshwater aquifer. The location of surface and subsurface drainage showed different effects on salinity advancement. By changing the location of drainage from A to f the amount of drained water in pipe and open drainage decreased by 5.8 and 6.5 m3/m, respectively. Drainage location also affected actual evaporation from soil surface and salinity accumulation in the soil surface layer. In the cases of drainage where the lowest and highest evaporation from the soil surface occurs respectively, 15% difference was observed. In the case of open drainage at a distance of 90 cm from the freshwater reservoir and a depth of 5 cm from the impermeable layer, the amount of actual evaporation from the soil surface during the whole simulation period is greater than the actual evaporation in non-drained condition and also caused increased salinity between two reservoirs. The subsurface barrier has generally blocked the saline water flow only when it has reached the impermeable layer. The profile of the water table is broken due to very low hydraulic conductivity (about 0.1 m per day) when it reaches the subsurface barrier. The amount of failure and drop of the water table increased with increasing barrier depth.

The salinity distribution parameters in the area between two aquifers, discharged drain from drainage and its concentration and protection of freshwater aquifer are affected and can be considered according to the condition of each location. On the other hand, each of the scenarios has a positive and negative effect on these factors, so according to each sample and specific location, it must be decided how to prevent the progression of salinity (drainage or subsurface barrier) and their location.

Sustainable agriculture at arid and semi-arid areas depends on optimized usage of fresh water resources. Evaporation from soil surface and deep percolation categorized as unuseful losses at irrigation, so their reduction could increase the root water uptake efficiency and yield production. Subsurface drip irrigation could provide this situation. Proper depth for installing dripper is the place that reduces soil surface evaporation and deep percolation. The objective of this study was to investigate the effects of various dripper installation depth on soil water content distribution and root water uptake and to choose the proper depth. For this purpose, HYDRUS-2D software was used to investigate the effect of three factors on non-beneficial losses and consumed water in drip irrigation, numerically. These factors were soil texture (loam, clay loam and sandy loam), installation depth (0, 10, 15 and 20 Cm) and dripper discharge (1, 2, 4 and 8 l.h-1). The results showed, although increasing the installation depth could reduce cumulative evaporation up to 40%, but the best installation depth was 15 Cm with discharge rate of 1 l.h-1, according to the amount of deep percolation and consumed water. The effect of soil texture was more than the effect of installation depth on the amount of irrigation water, so that the amount of irrigation water in 2 l.h-1 discharge rate was 2.9, 3.1 and 4.6 m3.m-1 for loam, clay loam and sandy loam soil texture, respectively. Also, for clay loam texture, dripper discharge had the highest effect on root water uptake and the installation depth had the lowest effect on soil surface evaporation.

The phenomenon of mixing saline and fresh water in aquifers near the sea coasts and the margin of salt marshland, limits the application of high-quality groundwater resources. On the other hand, by increasing concentration of saline water in aquifer due to evaporation from the soil surface and also decreasing pressure head in freshwater aquifers as a result of groundwater over exploitation, lead the mixing front advances toward the freshwater aquifer. In this study, by making a physical model, mixing area and salt distribution in both saturated and non-saturated zone of porous media has been studied. Four different hydraulic scenarios have been performed, including equal water table of fresh and saline water, higher freshwater level and two higher saline levels (10 and 15 centimetres). The concentration of saline water and freshwater were 20 and 0.98 dS/m, respectively. The physical model size was 4×1×1 meter. The results showed that the water table shape is an important factor for distribution and scattering of salinity in both saturated and non-saturated areas. By decreasing the water level in the freshwater reservoir by 10 and 15 centimetres, the boundary between the fresh and saline zone below the water table progressed 55 and 96 cm respectively, and by increasing the water level in the freshwater reservoir by 5 cm, the same zone has had a recession to 28 cm.

One of the threating factors to fresh water resources is the advancement of saline water and intrusion into the groundwater aquifer. This problem occurs in coastal zones and desert margins which causes reduction in the quality of fresh water. Evaporation from the soil surface and the water table depth are factors affecting the salinity and salt distribution in the saturated and unsaturated zones. In this study, by constructing a physical model with dimensions of 4×1×1 m, the proposed situation of saline and fresh aquifer levels was studied in four different hydraulic gradients. During the experiment, moisture and salinity data were collected from the physical model and then the salinity distribution in the physical model was numerically simulated using Hydrus-2D software. The results showed that Hydrus-2D model simulates moisture and salinity distribution well. The Maximum Normalized Root Mean Square Error (NRMSE) for simulation of moisture and salinity were 9.28 and 21.69 percent. The results showed that the pattern of salinity progression and regression were different. In conditions where the fresh water level is higher, it prevents the advance of saline water in saturated zone, and in unsaturated zone it does not have a significant effect on controlling salinity due to evaporation from the soil surface. In the saturated zone, when the saline and fresh water levels were equal, three units salinity increase in saline zone and when the saline water level was higher, 6.5 units salinity increase was observed in the middle of the two saline and fresh water reservoirs.

Estimating infiltration amount is very important in irrigation canals. In this regard, there are different methods to obtain the infiltration amount. The studies done to estimate the seepage rates in Iran’s irrigation networks are based on the mass balance method. Ponding test is a benchmark method to determine the canal seepage rate. In this method, a specific distance of the canal is isolated and the seepage rate is obtained by measuring the water level reduction in the pond. In this study, the feasibility of using conventional infiltration models; Kostiakov-Luis, Philip, Green-Ampt, and S.C.S has been investigated to estimate the seepage rate based on the ponding test data. Employing the field data of some ponding tests carried out in irrigation network of Australia, it was found that Kostiakov-Luis, with mean absolute relative errors between 2.3% to 7.4%, is the best model to estimate the infiltration rate in the canal. Although the current methods give a constant seepage rate irrespective of the canal flow depth, the outcome of this study indicates that the seepage rate is not a constant value. It depends significantly on the elapsed time, water level, and soil moisture. Also, it was found that the proposed method is less sensitive to the data gathering duration compared to the current methods.