Mohammad Hassanli; Peyman Afrasiab; Mahmoud Sabuhi; Hamed Ebrahimian
Abstract
The economic value of water is one of the most important factors for allocating water among various consumptions and encouraging users to take necessary actions to increase investments related to improving water productivity. There are several methods for economic valuation of water. In this study, due ...
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The economic value of water is one of the most important factors for allocating water among various consumptions and encouraging users to take necessary actions to increase investments related to improving water productivity. There are several methods for economic valuation of water. In this study, due to the key role of water in irrigation of agricultural products, residual valuation method was used for agricultural wells in Varamin County, with a wide range of water salinity. The average economic values of water for cucurbits, wheat, barley, and alfalfa were 2513.1, 5334.5, 1933.0 and 5647.6 Iranian Rials per cubic meters (IRR.m-3), respectively. The exchange price of water among the farmers in the study area was calculated as 5231.8 IRR.m-3, which was close to the calculated residual value for wheat and alfalfa crops. The coefficient of determination (R2) for the relationship of economic value and salinity of irrigation water for the above crops was 0.806, 0.878, 0.865 and 0.702, respectively, which indicates that the main changes of economic value of water is related to salinity of water. According to the relationship between salinity and irrigation water value in the study area, the residual value of water was zero in the electrical conductivity of 3.61, 7.30, 6.05, and 8.24 dS.m-1 for cucurbits, wheat, barley, and alfalfa, respectively. As a result, the water pricing policy in the study area should be such that for water salinities higher than the mentioned values, the selling price of water is set lower than the current value, so that the farmers do not suffer losses. Another option is that choice of crop should be based on greater resistance to salinity and its economic value.
Hamed Nozari; Azin Poursadri; Saeed Azadi; abdolmajid liaghat
Abstract
After installing subsurface drainage system, quality of drainage water in saline lands continuously changes, starting from the beginning of irrigation and drainage network operation, until reaching a more or less equilibrium state. Reaching a state of equilibrium in areas with saline groundwater may ...
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After installing subsurface drainage system, quality of drainage water in saline lands continuously changes, starting from the beginning of irrigation and drainage network operation, until reaching a more or less equilibrium state. Reaching a state of equilibrium in areas with saline groundwater may take several years. In this regard, field experiments are useful but they also have significant limitations. As an alternative, simulation models are among the methods that greatly eliminate these limitations. Therefore, in this research, the performance of DRAINMOD-S model was evaluated in simulation of drainage volume, drainage water salinity, and water table fluctuations. To validate the results of the model, data collected in the 2007-2008 cropping year from ARC18-18 farm was used in the research site of Sugarcane Research Center (Amir Kabir Agro Industrial Development Unit of Sugarcane Development Company, Khuzestan Province). This information included meteorological and soil data, drainage outflow, irrigation water salinity, water salinity within piezometers, and drainage water salinity. After statistical analysis and calculating the root mean square error (RMSE) and standard error (SE), the fits between the measured and simulated values of drainage water salinity, groundwater salinity, water table fluctuations and drainage discharge were investigated. The RMSE statistical index was 4.76 dS /m for drainage water salinity, 0.82 dS/m for groundwater salinity, 21.2 cm for groundwater surface and 2.1 L/s for the drain discharge, which indicated a fairly good accuracy compared with actual conditions. The results showed that the model was capable of simulating the water level fluctuations, drainage outflow and its salinity in Khuzestan region with saline and shallow groundwater table.