Zahra Majidifar - Academia.edu (original) (raw)
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Papers by Zahra Majidifar
International Journal of Research Studies in Agricultural Sciences, 2017
Accurate measurements of hydraulic characteristics of flow are needed for design and evaluation o... more Accurate measurements of hydraulic characteristics of flow are needed for design and evaluation of irrigation systems. For measuring flow, flumes are commonly used. is in order to obtain accurate readings for flow measurement, flumes should not be submerged and the upstream flow should not be affected by the downstream flow. This study investigates a proper way to install trapezoidal flumes that can be applied in many ways to measure in flow and outflow discharge in furrow irrigation systems. During sixty field operations, it was discovered that the flume has to be installed at least four centimeters above the bottom of furrow, in addition to the alignment on each side. This is essential for proper functioning of the flume under the conditions of free flow., Measurements made showed that if flume was held four centimeters above the bottom, the percentage of submergence in different depths of water, had met the standard rate (lower than 70% submergence), and hence the percentage of the error in flow measurement was reduced. In order to ensure the free flow in the trapezoidal flume, the large number of field operations showed that the entrance of the flume, which is used to analyze the inflow, has to be installed at a height of four centimeters or more above the bottom of furrow, with the condition that its entrance borders are strengthened. The exit of the flume should also be firmly fixed on the bottom of furrow in order not to impede the passage of flow, with the condition that beneath the flume the furrow bottom should be made deeper in order to create free flow. These recommendations are important, especially in furrow irrigation systems.
International Journal of Constructive Research in Civil Engineering, 2017
In recent years, many countries, especially those with dry climate, have been facing water shorta... more In recent years, many countries, especially those with dry climate, have been facing water shortages and have therefore resorted to indiscriminate use of groundwater that has led to the deterioration of ground water quality and reduction of groundwater resources. It has been estimated that Iran has 413 billion cubic meters of available water and56 billion cubic meters are extracted from underground aquifers. In 2001uncontrolled exploitation of about 5.5 billion cubic meters was recorded. Ground water is the main source of water supply in dry and semi-dry areas [1-3] as well as for domestic consumption in many cities of Iran and for agricultural use. Therefore, attention should be paid to the quantity and quality of groundwater resources and their management, especially in dry and semidry areas. Given the scarcity of fresh water resources, crop management and decision-making on land use are of particular importance. Isfahan province, like many other parts of the country, has experienced tworare drought periods over the past 18 years since 1999.Droughts, particularly in the East of Isfahan, have led to drying of about 43 thousand hectares of agricultural land, causing huge damages to farmers who are leaving farmland, and migration from the region to other are asin several cases which is leading to negative social, cultural and economic consequences. In some areas, water quality
In order to optimize the usage of water in agriculture, it is necessary to increase the efficienc... more In order to optimize the usage of water in agriculture, it is necessary to increase the efficiency of irrigation systems, especially those of surface irrigation. One of the steps to be made to achieve this goal is the optimal design of surface irrigation. It this article the design variables of furrow irrigation, that includes length of furrow, inflow rate and irrigation time (time of cutoff), were calculated to minimize the irrigation costs, the objective function, and to obtain a maximum application efficiency. The objective function encompasses water, labor, head ditch and furrow digging (ditch constructions) costs. Labor cost is irrigation time's function and the latter is dependent on water advance period in the furrows. Therefore, it is necessary for the objective function to apply explicit and accurate equation in order to calculate time of advance. Because in none of the accurate methods for furrow irrigation design, such as zero-inertia modeling, the advance time is exp...
International Journal of Research Studies in Agricultural Sciences, 2017
Accurate measurements of hydraulic characteristics of flow are needed for design and evaluation o... more Accurate measurements of hydraulic characteristics of flow are needed for design and evaluation of irrigation systems. For measuring flow, flumes are commonly used. is in order to obtain accurate readings for flow measurement, flumes should not be submerged and the upstream flow should not be affected by the downstream flow. This study investigates a proper way to install trapezoidal flumes that can be applied in many ways to measure in flow and outflow discharge in furrow irrigation systems. During sixty field operations, it was discovered that the flume has to be installed at least four centimeters above the bottom of furrow, in addition to the alignment on each side. This is essential for proper functioning of the flume under the conditions of free flow., Measurements made showed that if flume was held four centimeters above the bottom, the percentage of submergence in different depths of water, had met the standard rate (lower than 70% submergence), and hence the percentage of the error in flow measurement was reduced. In order to ensure the free flow in the trapezoidal flume, the large number of field operations showed that the entrance of the flume, which is used to analyze the inflow, has to be installed at a height of four centimeters or more above the bottom of furrow, with the condition that its entrance borders are strengthened. The exit of the flume should also be firmly fixed on the bottom of furrow in order not to impede the passage of flow, with the condition that beneath the flume the furrow bottom should be made deeper in order to create free flow. These recommendations are important, especially in furrow irrigation systems.
International Journal of Constructive Research in Civil Engineering, 2017
In recent years, many countries, especially those with dry climate, have been facing water shorta... more In recent years, many countries, especially those with dry climate, have been facing water shortages and have therefore resorted to indiscriminate use of groundwater that has led to the deterioration of ground water quality and reduction of groundwater resources. It has been estimated that Iran has 413 billion cubic meters of available water and56 billion cubic meters are extracted from underground aquifers. In 2001uncontrolled exploitation of about 5.5 billion cubic meters was recorded. Ground water is the main source of water supply in dry and semi-dry areas [1-3] as well as for domestic consumption in many cities of Iran and for agricultural use. Therefore, attention should be paid to the quantity and quality of groundwater resources and their management, especially in dry and semidry areas. Given the scarcity of fresh water resources, crop management and decision-making on land use are of particular importance. Isfahan province, like many other parts of the country, has experienced tworare drought periods over the past 18 years since 1999.Droughts, particularly in the East of Isfahan, have led to drying of about 43 thousand hectares of agricultural land, causing huge damages to farmers who are leaving farmland, and migration from the region to other are asin several cases which is leading to negative social, cultural and economic consequences. In some areas, water quality
In order to optimize the usage of water in agriculture, it is necessary to increase the efficienc... more In order to optimize the usage of water in agriculture, it is necessary to increase the efficiency of irrigation systems, especially those of surface irrigation. One of the steps to be made to achieve this goal is the optimal design of surface irrigation. It this article the design variables of furrow irrigation, that includes length of furrow, inflow rate and irrigation time (time of cutoff), were calculated to minimize the irrigation costs, the objective function, and to obtain a maximum application efficiency. The objective function encompasses water, labor, head ditch and furrow digging (ditch constructions) costs. Labor cost is irrigation time's function and the latter is dependent on water advance period in the furrows. Therefore, it is necessary for the objective function to apply explicit and accurate equation in order to calculate time of advance. Because in none of the accurate methods for furrow irrigation design, such as zero-inertia modeling, the advance time is exp...