Showing 8 results for Water Balance
M Mahbod, Alireza Sepaskhah, Marzih Monfared,
Volume 13, Issue 49 (10-2009)
Abstract
Optimum management of water use in agriculture results in higher cultivated areas or enhances the share of water for municipal and industrial uses leading to economic development of a country. One of the effective methods in optimum water management is irrigation scheduling by using models which simulate water content in soils. In this study, a previously prepared model for irrigation water scheduling was modified to calculate daily effective rain, soil water content and deficiency. The model was applied for winter wheat field in Bajgah area using 13 years of local meteorological data. Furthermore, the effect of water storage in the soil profile on the amount and frequency of irrigation was examined. This model was written in Visual Basic.Net programming software. The model was run under two assumptions: 1) the effective rain compensates water deficiency of soil down to daily root depth and the excess water is assumed as deep percolation (case I) 2) the effective rain compensates water deficiency of soil down to maximum root depth and the excess water is assumed as deep percolation (case II). The results show that the amount and the frequency of irrigation in case 2 is less than case 1. Average amount and number of irrigation events decreased from 706.8 (mm) and 8 in case I to 569.2 and 6.4 in case II. The average relative percentage of effective rain increased from 45.2 % in case I to 76.9% in case II. The effective rain is 108.9 mm and the amount and number of irrigation events is 9 and 757.7 mm, respectively in case I (at probability level of 80%). The effective rain is 236.7 mm and the amount and number of irrigation events is 636.9 mm and 7.2, respectively in case II (at probability level of 50%). The effective rain is 165.6 mm and the amount and number of irrigation events is 712.6 mm 8, respectively in case I. The effective rain is 292.1 mm and the amount and number of irrigation events is 545.1 and 6, respectively in case II.
H. Ghamar Nia, M. Jafari Zadeh, E. Miri, M.e Ghobadi,
Volume 17, Issue 66 (2-2014)
Abstract
The estimation of crop water requirement is one the most important stages for designing different irrigation systems, programming and corrected management of water resources. Therefore, to determine the water requirement for Coriandrum sativum L. a study was conducted in College of Agriculture Research Farm at Razi University in the city of Kermanshah during two years, 2010 and 2011. For this purpose, three water balance drainable lysimeters with the diameter of 1.20m and height of 1.40 m were used. During the investigation, the irrigation was determined by using data logger equipment of (IDRG). The soil humidity was determined in the field capacity condition. The evapotranspiration was calculated using water balance equation. Finally, the Coriandrum sativum L. water requirement was determined to be 722.95 and 580.64mm for years 1388-1389 and 1389-1390, respectively. Meanwhile, the potential evapotranspiration using the Penman Monteith equation was calculated to be 643.58 and 530.17mm for the first and second year of investigation, respectively.
S. H. Sadeghi, H. Ghasemieh, S. J. Sadatinegad,
Volume 19, Issue 73 (11-2015)
Abstract
Rainfall- runoff modeling and river discharge forecasting are an important step toward flood management and control, design of hydraulic structures in basins and drought management. The purpose of this study was simulating the daily flows in the Navrud watershed using WetSpa model. WetSpa is a hydrological- physical model that can predict flood on the watershed scale with different time steps. This model uses topography, land use and soil texture layers and also, the daily meteorological data to predict the flow hydrograph. In this study, the data of 4 stations (Khlyan, Khrjgyl, Gavkhs, Nav) during the water years 2006-2011 were used. 36 months from September 2006 and 36 months from September 2009 to September 2011 were selected for calibration and test of model, respectively. Simulation results of WetSpa model showed that this model simulates river Daily flow using collective measures of 0.63 and 0.61 in calibration and test periods, respectively. According to this result, it can be stated that the model estimates peak discharge and flow volume in both periods very well. Also, this model could simulate well the water balance of Navrud Basin.
M. Hosseini, M. Ghafouri, Z. Tabatabaei, M. R. Mokarian,
Volume 20, Issue 78 (1-2017)
Abstract
In the last decades, climate change and fluctuation of water balance have been the main reason to apply hydrologic models for estimating quality and quantity of water components as efficient tools in water planning of critical conditions. In addition, these hydrologic models with potential to study the effects of watershed management practices on the runoff components are suitable tools for optimization of watershed operations at present and future. In this research Soil and Water Assessment Tools (SWAT) model has been applied to estimate groundwater runoff for 6 provinces such as Eilam (Golgol Catchment), Boushehr (Baghan Catchment), Khozestan (Morghab Catchment), Fars (Shekastian Catchment), Kohkiloyeh & Boyer Ahmad(Tange Birim Catchment) and Hormozgan (Daragah Catchment) which are located in south and south west of Iran. In order to evaluate the performance of the model, hydrological data, soil, land use and Digital Elevation Model (DEM) entered for each catchment to run the SWAT model. SWAT-CUP with SUFI2 program was used for simulation, uncertainty and validation with 95ppu. P-factor and R-factor are two internal evaluation factors in SUFI2 program and indicators such as the coefficient of determination (R2) and Nash- Sutcliffe (NS) were used for evaluation of the model. The Nash-Sutcliffe coefficients in six mentioned catchments for calibration period are 0.66, 0.73, 0.40, 0.32, 0.53 and 0.78. They are 0.49, 0.48, 0.42, 0.45, 0.46 and 0.62 for validation period, respectively. Model calibration and validation results showed good performance in estimating the water balance of the basins studied. Except for Shecastian catchment, the evaluation results showed acceptable and favorable results for water balance in the study area.
M. Raeisi Asadabadi, M. R. Nour, R. Fattahi,
Volume 22, Issue 2 (9-2018)
Abstract
In order to optimize the irrigation system performance, it is essential to get information about water balance components in the farm. So, the objective of this study was evaluating the performance of the WFD device in determining water penetrated fate in the soil at each irrigation occurrence as one of the important components in evaluating the irrigation water efficiency. By having the water amount infiltrated in the root zone and the deep percolation amount collected and determined by WFD device, contribution of surface losses related to every irrigation occurrence can be determined by the employing water balance equation. This research was carried out in the form of completely randomized design blocks in three replications and under the treatments of 60, 80, 100 and 120% of the irrigation requirement supply of a potato plant in the research farm of Shahr-e Kord University in 2014. To gather the growing season data, before the planting operation, various WFD devices were installed at different depths and locations along furrow. In addition to WFD data, input discharge (using counter), output discharge (measured by flume type 1) and values of soil moisture (theta-probe device) were collected during the harvesting season. The results showed that the mean Nash–Satcliffe coefficient of comparison between the values of calculated and measured surface losses corresponding to it, and also comparison of the values of the calculated and measured residual moisture before each irrigation occurrence were obtained to be 0.87 and 0.98, respectively. Quantity of this indicator in the two conducted comparisons represented the correct and exact performance of the WFD device in the farm operation evaluation. During the farm evaluation process under the experimental furrow, distribution uniformity averages in the experimental treatments were acquired to be 75.56, 83.78, 88.06, and 90.34%, respectively. Likewise, water amount average percolation of root zone (depth losses) in experimental treatments at each irrigation occurrence was measured to be 0.02, 0.07, 0.27 and 0.47m3 for each furrow.
Sh. Nasiri, N. Farrahi, A. N. Ziaei,
Volume 24, Issue 2 (7-2020)
Abstract
One of the most important and complex processes in the watersheds is the identification and prediction of surface water changes. The main processes associated with surface water include precipitation, percolation, evapotranspiration and runoff. In this research, the semi-distributed model, SWAT, was used to simulate ground water and surface water in Semnan catchment in a monthly scale. A sensitivity analysis was perfomed to evaluate and demonstrate the influence of the model parameters on the four major components of water budget including surface runoff, lateral flow, groundwater and evapotranspiration. River discharge data from 2004 to 2014 were used for the calibration and those of 2014 to 2016 were applied for the validation. The results of sensitivity analysis showed that the most sensitive parameters were: SoL_K(Saturated hydraulic conductivity), CH_K2 (Effective hydraulic conductivity in main channel), RCHRG_DP(Deep aquifer percolation fraction and CN2 (Moisture condition II curve number). The simulation accuracy using Nash-Sutcliffe and coefficient of determination for Shahrmirzad, Darjazin, and Haji Abad hydrometric stations was about 0.60 to 0.80 and 0.80 to 0.90 for the calibration and validation period, respectively, showing a good performance in the simulation of river flow. According to the water balance results, about 87.6% of the total inflow into the watershed was actual evapotranspiration, 3% was surface run off, 3% was percolation, and the rest was related to the soil moisture storage.
S. Khalilian, M. Sarai Tabrizi, H. Babazadeh, A. Saremi,
Volume 24, Issue 4 (2-2021)
Abstract
In the present study, the SWAT hydrological model was developed for the upstream of the Zayandehrood dam to evaluate the inflow to this dam. Accordingly, after entering the meteorological and hydrometric information of the region, the runoff simulation was performed. Due to the high volume of entrances to the Zayandehrood Dam, Shahrokh Castle hydrometric stations were selected as the base station for calibration and validation during the statistical period of 1990-2015. After hydrological simulation and accuracy of results, climate prediction was performed using the fifth model of the climate change for the RCP scenarios. According to the forecast, by using climate change models, the temperature could be assumed to increase in all models and the highest rate of increase would occur under the RCP 8.5 climate scenario. After evaluating climate change in different diffusion scenarios, the runoff of the basin was simulated in the SWAT model. The simulation results of runoff in the catchment area showed that although the amount of rainfall was increased in the region, increasing the temperature had a greater effect, reducing the amount of runoff in the basin. Based on the results of climate change, hydrological simulation was performed using the SWAT model. The results showed that the effect of diffusion scenarios in the region was different, causing an increase in temperature and precipitation. The highest increase was observed in the RCP8.5 scenario, which was consistent with the nature of this emission scenario, with the highest emission of greenhouse gases and carbon dioxide. Then, the evaluation of the hydrological model was done; the results showed that although the amount of rainfall in the region had been increased, the increase in temperature of this basin had a greater effect and efficiency in reducing the amount of runoff.
Sh. Nasiri, H. Ansari, A.n. Ziaei,
Volume 25, Issue 3 (12-2021)
Abstract
Reducing surface water resources and successive droughts and consequently excessive use of groundwater resources, especially for agricultural purposes, have caused irreparable damage to the natural resources of the country. In the meantime, knowing the status of the water balance of the plain can help to effective management of water resources in the region. Samalqan plain is located in a semi-arid climate in North Khorasan Province. Since the surface water resources for water supply are not very reliable, so, the main source of water supply in the region is
well. Due to the existence of rivers in the plain, the low thickness of the alluvium, groundwater level fluctuations, and the high uncertainty in the calculation of hydrodynamic coefficients, the need for careful hydrogeological studies and determining the role of each parameter affecting groundwater is necessary. This study was conducted to simulate the Samalqan aquifer and analysis of water balance for the years 2003 to 2013 using the MODFLOW model. To identify the groundwater recharge rate, this component was estimated by the SWAT model. Calibration and validation of the model with an error of 1.1% and 1.2%, respectively, indicated that an appropriate estimation between the simulated and observed heads. Assessment of the groundwater hydrograph in the observation wells showed that the groundwater level in most places has many monthly and seasonal fluctuations. After drawing the potential lines of the plain, the inputs and outputs were identified, and using the reserve volume changes, the water balance was determined. The results showed that the water balance of the plain was negative and the reservoir deficit was estimated at 9.14 million cubic meters. Therefore, this model can be used to predict the future situation of aquifer and the management of
water resources in the region.
