نشریه مهندسی آب
سال نهم شماره 4 (زمستان 1400)

The flow and drainage structures are widely used in irrigation and drainage networks due to their simple and relatively precise relationships. The flow causes the return of water and consequently increases the flow cross section and decreases the speed and also creates suitable conditions for sediment deposition and waste in the water, which is considered as a disadvantage of this structure. With the accumulation of sediments upstream, the flow conditions are changed and the accuracy of the extracted relationships is reduced to estimate the discharge. By combining the flow and valve, it is possible to reduce the problems and disadvantages of using each one alone and at the same time use their advantages so that the depositable materials behind the flow and accumulator in the hatch entrance pass through the substructure. Rhine, the combined behavior of spillway flow with jet out from under the hatch, creates different conditions downstream of such structures and causes scour changes downstream of this. The overall purpose of this study was to investigate the effect of valve opening rate on scouring rate in the case of discharge through the combined structure, upstream head height using flow-3D numerical model.The results show that by reducing the opening of the valve, the height of the water on the structure increases and causes the scour depth to increase. Also, by increasing the flow rate over the spillway and under the valve and the height of the upstream water, the maximum scour depth increases.

Due to the fact that many variables are effective in the amount of sediment trapping and the amount of water loss in the eddy tube, this study was conducted to investigate the performance of the eddy tube in laboratory conditions. 4 ratio of pipe gap width to pipe diameter (t / d), 0.15, 0.20, 0.25 and 0.3, 3 granulation D1 (particles passing through sieve 8 and remaining on sieve 10), D2 (particles passing through sieve 16 and remaining on sieve 20) and D3 (particles passing through sieve 20 and remaining on sieve 30) were selected at a 45 degree angle with different flow rates. The results showed that if the area is not facing water shortage and water supply problems and preventing sediment from entering the system is preferable to water supply, t / d = 0.3 is a more desirable option; But if it is very important in water supply areas and there is basically water shortage; The better option is t / d = 0.25.

Excess fluoride is one of the water pollutants in the world, which is removed from the water by chemical methods to produce sludge, and other methods such as R.O. also have problems in electricity consumption and wastewater disposal. Metal-organic complexes are one of the newest adsorbents used in the separation of anions. In this study, MOF 1 was used to remove fluoride from aqueous solution. Existing factors such as pH, contact time, adsorbent amount and temperature were examined. Based on the results, the MOF synthesized in acidic media absorbs more fluoride ions. Contact time of up to 20 minutes has a significant effect on the removal of fluoride ions and then its effect is greatly reduced. The amount of adsorbent used is up to saturation and the water environment has no significant effect on the absorption of fluoride ions. Also, the results of kinetic studies confirm the pseudo-second-order kinetic model for fluoride adsorption reactions in the presence of MOF1. Also in this research, zinc metal is used as a zebrafish as a central metal with the aim of reducing the environmental MOF.

When irrigating the field, the water moves along the strips and transfers most of the water to the ends of the strips, preventing uniform irrigation. In the present study, in order to solve the mentioned problem, a system was designed, constructed and evaluated for performance, which by filling the created furrows, solved the problem of non-uniform irrigation and improved irrigation performance. The system adjoining the plate boundary has two concave plates with a diameter of 35 cm, which float following the main plates of the boundary and along the created ridge, and by transferring a part of the soil of the ridge body, it fills the furrows. Field performance evaluation experiments were performed in 1397 in the research farm of the Faculty of Agriculture, Islamic Azad University, Shushtar Branch. Experimental treatments include: device type (boundary with furrow filling mechanism and boundary without furrow filling), plot distance (5 and 10 meters), on water loss rate (in cubic meters), labor cost to fill boundary furrows, Time of border demarcation operation by Marzband The results show that by using the border trench filling machine and at a distance of 10 meters, the minimum amount of water wasted in the amount of 9680 cubic meters, the lowest labor cost to fill the border trench 100,000 Tomans and the shortest time to do Border operations on agricultural land are 120 minutes per hectare.

The issue of water, food and energy security is becoming increasingly important in the face of the current growing population and the intensification of exploitation of limited and non-renewable resources. According to the World Bank, food security is "access of all people to adequate food at all times to have a healthy life", which has three main axes: "food availability", "food access" and "food sustainability". Therefore, the core of food security is access to healthy food and good nutrition. In this research, by the dimensions of security of water, food and energy, the relationship between this concept and land management is discussed. Studying the results of researches show that using modern irrigation systems, concluded expanding new irrigation methods and achieving sustainability, can be achieved Nexus of water, food and energy. The hypotheses that are effective in modern irrigation systems according to the concept of Nexus and land use planning can be evaluated according to the effect of these systems on food production and food security, the effect of systems on reverse migration, balanced distribution and financial resources and less energy consumption and more investment in the systems sector, which with the achievement of each of these cases, the effectiveness of the systems increases and its tremendous impact on land use planning is observed.

An irrigation planning is set in order to determining the soil water balance and estimation of the water future consumption based on the calculation or measuremant of the Evapotranspiration values, which providing a possibility for prediction of a real time that corresponding to the moisture index of management Allowed Deficit (MAD) in soil. This study was conducted for evaluation different reference evapotranspiration models in Islamabad-Gharb area. for this purpose, the monthly data of Islamabad-Gharb synoptic Meteorology stations during a period of 30-year (1394-1364)were used. After restruction of the missed data and verification of the reference stations, values of the evapotranspiration were calculated with 9 valied formulas using REF-ET software. In order to determine the best method, the output values of the models were compared with evaporation pan data, using some statistical criterio. According to the results, the highest correlation coeficient (r=0.99) was obtained between the output data of the Blaney- Cradle model and evaporation pan. Also the minimum root mean square error (RMSE) values of 22.2 (mm/day) and 24.42 (mm/day) were belogend to the models of torque and Blaney- Cradle, respectively. Furthermore the highest efficiency (EF) value(0.93) was obtained for the both models of Blaney- Cradle and torque. Hence by considering the resulted minimum mean percentage error (MAPE) value (0.01) for Blaney-Cradle, this model was proposed as the most suitable model for application in the studied area.