Samane Arvandi; Forood Sharifi; Ali Shahnazari
Abstract
Water is a major factor in food production and sustainability of ecosystems. The need for water resources is increasing. Due to the scarcity of water and also aridity in many regions, development of new technologies to meet the plant water needs is important at plant establishment and specifically at ...
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Water is a major factor in food production and sustainability of ecosystems. The need for water resources is increasing. Due to the scarcity of water and also aridity in many regions, development of new technologies to meet the plant water needs is important at plant establishment and specifically at the development stage. Development of new technologies is a key for solving the problem of water shortage. Steam condensation in soil (using renewable energies) is a new and developing method that has the potential of increasing water efficiency. In this method, the steam transfers directly to the root zone and increases the moisture content of the soil. The purpose of this study was to investigate the efficiency of evaporation-condensation irrigation system in increasing water use productivity and evaluating performance of this technology in moisture absorption of various soils improved using organic matter. In order to increase water condensation, the produced steam, conveyed into steam chambers and after distillation, it increases the moisture content of the soil. In this study, a number of experiments were conducted on small flumes. Results showed that the moisture condensation of the soil with organic matter 11% higher than that of soil without organic matter. Then, with the possibility of increasing the moisture with this method, the experiments were carried out in larger pots. The result of analysis of variance of soil texture, steam temperature and organic matter interactions showed that these three parameters had no significant effect on soil moisture increase. Based on the results, the soil with medium texture, 35% organic matter and steam at 45 °C in coated conducting tube showed better results than other treatments. The steam blown into vapor tubes in flume and pots was at two temperatures of 45 and 55 °C that 30°C was selected for planting. After determining the proper temperature and selecting soil texture, plant cultivation was carried out by evaporation-condensation irrigation method. Then the water consumption was compared with greenhouse and field planting. Selected soil for cultivating lettuce under controlled conditions and with evaporation-condensation irrigation, was designated to be medium and in combination with 35% organic matter and coated conducting tube at steam temperature of 30°C. The results of this study showed that after harvesting and full growth of lettuce in all three conditions, production per 1 m3 of water for lettuce in evaporation-condensation irrigation, greenhouse and field was 1250, 333 and 75.5 kilograms, respectively. Water use efficiency was investigated in all treatments and the results showed that there is a significant difference between different irrigation methods (P≼0.01), and the highest water use efficiency resulted from evaporation-condensation irrigation method. The consumed water during the growing period in the greenhouse was approximately 4 times that of evaporation-condensation irrigation method and in the field was about 21 times that of condensation irrigation, which indicates a significant reduction in water use. By examining dry matter the weight of lettuce in all three methods, the results showed that in all samples taken from condensation irrigation, greenhouse and field, the average dry matter was 12.5% and average water was 87.5%, which indicated the same quality of the product in all three methods.
Rahim Kazemi; Jahangir Porhemmat; Forood Sharifi
Abstract
The Flow Duration Curve (FDC) is a classical method used to graphically represent the relationship between the frequency and magnitude of stream flow and is required as a prerequisite for water resources management projects. In this study, by analyzing daily data of hydrodynamic stations, 47 stations ...
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The Flow Duration Curve (FDC) is a classical method used to graphically represent the relationship between the frequency and magnitude of stream flow and is required as a prerequisite for water resources management projects. In this study, by analyzing daily data of hydrodynamic stations, 47 stations with the appropriate statistics and the common period between 1976 and 2011 was selected in a semi-arid region of the country. Using a topographic map with a scale of 1: 50000 and determining the position of the stations, the study area was determined and 11 physiographic parameters influencing the flow duration curve including: average height, basin area, gravilillus coefficient, basin slope, main river length and hydrological parameters including annual rainfall, Base flow index, hydrograph recession constant, curve number, permeability and the number of rainy days were extracted for each basin. The flow duration curve indices were then extracted using daily flow data. Then factor analysis was performed and independent factors influencing the flow duration curve were determined. Finally, homogeneity was performed based on independent main factors and the regression relations of the curve indices were extracted in each homogeneous region.In order to investigate the validity and accuracy of the models in homogeneous regions, error-independent test methods, normal distribution of errors and control stations were used. The results showed that the selected factors for factor analysis in semi-arid climatic zone (75.875 percent) of the variance of data were explained. The six parameters of precipitation, curve number, slope, rainy days, permeability and area were known as the most effective parameters. The results of the accuracy assessment of the models using the control stations showed that the relative error of the relations presented in the homogeneous region was 0.17, 2.17, 2.73, 1.53 and 1.94, respectively. The normal distribution of errors, the coefficient of determination of more than 0.90 and the Durbin Watson coefficient between 1.5 to 2.5 also Nash-Sutcliff near "one" indicate the reliability of the regression relations presented for estimating the flow duration curve indices in the ungagged catchments in semi-arid areas of the country.
Forood Sharifi; Samane Arvandi
Abstract
This research was carried out to; evaluate the hydrological processes (rainfall, runoff, evaporation, infiltration, etc.), study the water capacity, to simulate the behavior of watersheds. After examining a number of simulation models, the SFBM, AWBM2002, SCS and ISDI were selected and adjusted. Data ...
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This research was carried out to; evaluate the hydrological processes (rainfall, runoff, evaporation, infiltration, etc.), study the water capacity, to simulate the behavior of watersheds. After examining a number of simulation models, the SFBM, AWBM2002, SCS and ISDI were selected and adjusted. Data from 15 catchments and a representative watershed were used. The results such as, simulation parameters, runoff threshold, flow duration curve, snow line, flow recession curve, and base flow index are analysed. The results showed that the models, can well simulate the runoff, and are able to estimate response of ungauged catchments, and form a good capability for design and research. In more than 61.5% of the area, after a rainfall of 5 to 10 mm, runoff generates, hence it was concluded that most of the basins are susceptible to flooding. Also, the highest threshold value in the Bandar Gaz basin is 20 mm, with a maximum specific discharge of 0.27 m3/km2. The lowest value was obtained in Azadshahr and Gonbad-Kavoos basins, respectively, equal to 2 and 4 mm, with a specific instantaneous flow rate of 0.16 in the Gonbad-Kavo basin to 0.26 m3/km2 in the basin no. 171. Also, the highest threshold value in the Bandar Gaz basin is 20 mm, with a specific maximum discharge of 0.27 m3/km2. Among the basins of the similar areas, the Delour Qotorchai Basin with an area of 45.2 km2 with a maximum specific discharge of 0.49 m3/km2, the highest and middle Shor basins, with an area of 37.22 km2and Gorgan Bay with an area of 299.26 km2 with a discharge of 0.04 m3/sec/km2.The results indicated that the runoff threshold has a good correlation with precipitation. The results of the dryness model showed that the model with a high correlation coefficient (83%) simulated the discharge.
