جستجوی مقالات مرتبط با کلیدواژه "بیلان آب" در نشریات گروه "مهندسی آب"

Actual evapotranspiration (AET) plays an important role in agricultural water management, drought forecasting, and climate change projection. In recent years, the use of indirect methods to estimate AET has led to the development of various databases. The existence of various uncertainties in these data makes their evaluation necessary. In this study, focusing on the historical period of climate studies (1976-2005), the estimated values of AET by means of the Thornthwaite water balance model were used as a basis for evaluating GLEAM and GLDAS databases, in Nazlou Chay, Rozeh Chay, Shahr Chay, and Barandouz Chay sub-basins in the west of Lake Urmia. The results showed that on an annual scale, the difference between GLEAM and GLDAS databases was not noticeable (RMSEGLEAM=0.13-0.46 mm/day, RMSEGLDAS=0.13-0.48 mm/day). But on a seasonal scale, the performance of GLEAM and GLDAS data differed in different seasons. Based on the evaluation criteria, the GLEAM database performed better than the GLDAS (GLEAM: RMSEWinetr=0.11-0.33, RMSESpring=0.25-1.15, RMSESummer=0.58-0.77, RMSEAutumn=0.15-0.33; GLDAS: RMSEWinetr=0.15-0.27, RMSESpring=0.32-1.14, RMSESummer=0.64-0.95, RMSEAutumn=0.15-0.40). Also, in annual and seasonal scales, GLEAM and GLDAS data were more reliable in Shahr Chay sub-basin (RMSEShahrchay=0.12-0.58, RMSENazlouchay=0.15-0.85, RMSERozehchay=0.19-1.15, RMSEBarandouzchay=0.11-0.77). According to the results of the present study, it is not recommended to use GLEAM and GLDAS data in hydrometeorological studies in Nazlou Chay and Rozeh Chay sub-basins. The results of the present study can be used in the studies of projecting AET future changes, as a basis for evaluating the outputs of climate models as well as correcting their bias.

Estimation of agricultural water consumption with unrealistic bases causes more aggravation of the current Iran water crisis. Accordingly using broader information, especially water budget components which received less attention, can be effective in enhancing such estimates. To this aim, this study developed a framework based on grouping of agricultural crops and the concept of "water footprint". The framework also includes an optimization module to examine consequences of the policies such as increasing self-sufficiency rates of agricultural crops under best optimum management on water budget. Accordingly, the consumption of agricultural sector for 2017 was estimated to be 64 BCM, which was associated with a negative balance of 5.5 BCM. Furthermore, the targets of the 6th national development plan (2016-2021) regarding three crop groups including oil seeds, sugar crops and maize were examined (target values were respectively about 3.2, 1.4 and 3.2 times of their productions in 2017). The results showed that by expansion of the cultivation area to achieve these targets, country’s negative water budget will increase to -12.5 BCM/yr. With the same assumption and a 30% reduction in vegetables and fruits, the negative budget would reduce to -10.5 and with the most optimum provincial crop patterns, it reaches -8.5 BCM/yr. What investigated here was an attempt for improving the estimation of agriculture water consumption, reducing related uncertainties and elucidating the alerting consequences of increasing self-sufficiency rates on the water balance. Nonetheless follow ups are needed to improve such methodologies.

Hydrological cycle is directed into thermodynamic non-equilibrium state and maximum entropy production through thermodynamic processes. Therefore, it is possible to understand and describe hydrological cycle through computation of entropy production rate and the maximum entropy production principle (MEP). Based on MEP, if there are sufficient degrees of freedom within a system, it will adopt a steady state at which entropy production is maximized under existing restrictions. This principle can help to estimate the hydrological components and parameters without need for detailed understanding of watershed characteristics. Due to the importance of this issue in the science of hydrological modeling and the lack of Persian resources in this field, the present study examines the hydrological cycle from a thermodynamic point of view using valid scientific sources. In this study, the hydrological cycle is considered as a thermodynamic system and the method of calculating entropy production rate by components of water balance is presented. Also, how to estimate hydrological components using the MEP principle is explained in a simple example. Overall, the MEP principle holds great promise for equipping us with a better understanding of the organization of hydrological processes within the Earth system and development of the models based on non-equilibrium thermodynamic.

In management and planning of water resources, hydrological models are suitable tool that can be very effective in simulating hydrological processes such as water balance. Distributed hydrological models simulate each of the water balance parameters by discretization and solving equations in each cell. In the present study, the WetSpass-M distributed model is used to estimate and evaluate the components of the water balance in Hashtgerd study area in Alborz province. The model was implemented in monthly basis and for a 20 year period. In order to calibrate and validate the model, first the monthly flow data of the hydrometric station were used as observational data. The remote sensing approach (SEBAL algorithm) was applied to re-estimate evapotranspiration. Then, the results of the two approaches were evaluated and compared. According to the model results in the Hashtgerd study area, the mean annual values of evapotranspiration and groundwater recharge were estimated to be 347.3 and 272.6 MCM, respectively. Furthermore, the mean annual values of evapotranspiration for plains and mountains were respectively 241 and 106.3 MCM. The mean annual recharge rate in the plains was equal to 197 MCM, while it was estimated to be 75.6 MCM for mountains. The variations analysis of model outputs was performed based on the standard deviation for the water balance parameters in plains and mountains. The results showed that the most variations during the simulation period were observed respectively in the irrigation component, evapotranspiration, recharge, and rainfall.

In order to ensure sustainable water management, a thorough understanding of the hydrological conditions and the interactions between surface and ground water. In this paper used from corrected multifunctional and integrated hydrologic model SWAT-MODFLOW to simulation quantitative processes of surface and ground water and simultaneous exchanges between them at the Shazand catchment. After the calibration, results of calibration SWAT surface water model to Duab bridge hydrometrical station that located at the Shara river and the basin's output, shown coefficient value of R2 and Nash-Sutcliff 0.64 and 0.63, respectively. At the groundwater part, the amount of RMSE for 19 observational wells calculated 1.72 m that is an acceptable level. With regard to the results obtained in the two surface and ground water sections, the performance of the model with regard to the integrity and consideration of all exchanges of the two models is concurrently and in a wide area acceptable and can recommended use from integrated SWAT-MODFLOW model In integrated simulation of the hydrological conditions of the catchment in a comprehensive manner. To evaluate the application of SWAT-MODFLOW integrated model at the basin level, the model was used to estimate the impact of a 10% reduction in water resources scenario using an index on the existing water resources system, the results obtained from the water index. The availability of WAI used in this study indicates an improvement in the value of the indicator and thus an improvement in the status of the water resources system compared to the status quo.

In this research, water balance components in Mehrgerd watershed was simulated using the SWAT hydrological model. The main purpose of this research is the model efficiency test and its ability to use as a water balance simulator in the Mehrgerd watershed. For this purpose, the necessary data such as precipitation, minimum and maximum temperature, relative humidity, sunshine hours, daily wind speed, monthly discharge and as well as required maps including digital elevation model (DEM), land use and soil were provided. and entered to the SWAT model. A sensitivity analysis was done using the )OAT( method to determine the sensitive parameters. The calibration and validation of the model were done by Sufi-2 algorithm. The calibration process was conducted for the period 2004 to 2012 while the validation process was from 2013 to 2016. Monthly runoff simulation accuracy was calculated using the determination coefficient (R²) and Nash Sutcliffe (NSE) index for calibration and validation 0.73, 0.69 and 0.71, 0.58, respectively. The results showed that 64 % of precipitation enters the atmosphere through evapotranspiration. Approximately, 31% of it goes to the waterway as the surface runoff and lateral flow. Finally, from 6 % of water entered into the soil layers, close to 1 % of it joins to the underground water. The results of this research show the acceptable performance of the SWAT model to simulate the water balance in Mehrgerd watershed. Therefore, this model can be used for water resources planning in this study area.

The main purpose of this study is reform, development and evaluation of dynamic water balance model “DWB” with the approach of the proportional coefficients “To the kind of hydrological reality-based constraints” and acts the withdrawal of groundwater and surface water resources along with calibration and uncertainty analysis its parameter. The results showed that generally cannot obtain a set of optimal parameters for calibration SDDWB and DWB model and often the parameters of the models are low detection capability for model calibration in both study area (Neyshabur and Rokh watershed). The average total amount of surface water balance error DWB model for Neyshabur and Rokh watershed is Respectively -9.74 and -69.63 Cubic meters that is Represented poor performance model. there is a significant difference between Aquifer volume changes observed and simulated by DWB That the main reason is the lack beneficial effects of groundwater withdrawals in this model. Reviews performance results showed that the relative PRMSE index of the SDDWB model for both the study areas less than 10 percent, indicating acceptable accuracy SDDWB model. In general, the results indicate that the overall error rate of surface and groundwater discharge equation components using SDDWB model is much lower than the DWB model, which indicates the positive impact reform and development on the DWB model.

To optimal and sustainable management of water resources in watershed scale, estimation of water balance and important to know of the different parameters of the water balance is inevitable. Goal of this study, is estimating the volume of actual evapotranspiration, infiltration, surface and subsurface flow based on hydrologic balance in Marghab and Abgelal watersheds. Hydrological balance in the hydrological stations these watersheds was calculated using the Salas approach. Results indicated that in Abgelal watershed, from 597 mm average of rainfall, about 438 mm is evaporated and about 95 mm as runoff out of the watershed. Thus, 64 mm of the total rainfall infiltrated. In the Marghab watershed, maximum of rainfall as runoff out of the watershed, so from amount of annually rainfall that is equal with 641 mm, amount of 192 mm as evapotranspiration and amount of 72 mm as infiltration and 377 mm as runoff out of the watershed. Model evaluation for the two stations was conducted using the error parameters such as Nash – Sutcliffe Error (NSE), Root-Mean-Square Error (RMSE) and Mean Absolute Error (MAE), results indicate that performance of model is better in Marghab station than Baghmalek station.

Due to lack of appropriate data, estimation of water balance components for large areas is usually problematic. Recent development of global databases based on satellite estimates as well as rapid progress in hardware and software for modeling of complex processes governing the water balance at the land surface, caused that many efforts employ these new tools to reduce the limitations in this field. Gravity Recovery and Climate Experiment (GRACE) and Global Land Data Assimilation System (GLDAS) are two particular projects, which has recently been used by many scientists to estimate water balance in different regions of the world. Regarding the lack of attention to this free information in Iranian studies, this research aims at investigating the possibility of using these resources in estimating the water balance of Iran basins. Urmia lake watershed was selected as a study area and the water balance components were extracted from GRACE GLDAS data. Comparison of the estimated changes in total water balance of the basin by GRACE data and changes in the lake water volume based on observations showed a similar trend. Besides, estimation of annual variations in groundwater using GRACE and GLDAS showed suitability of GRACE data for study of the groundwater changes. Overall, the results of present study indicated that GRACE data can be used as an appropriate tool to perform a preliminary, rapid, and inexpensive assessment of water balance in watersheds of the country.

Today, water scarcity is one of the main problems around the world, especially in arid and semi arid regions. Iran is a country that is now faced with water scarcity. One of the effective solutions for water management in arid catchments is determination and analysis of water balance components. So this study has focused on determination of water balance components in arid-mountainous catchment of Manshad in Yazd province, during 2006-2007 cropping season. To estimate actual daily evapotranspiration (ETa) of the region, time series of MODIS images were acquired and used via the surface energy balance algorithm for land (SEBAL)methodology. Annual ETa then was calculated in the form of a pixel by pixel basis map. Also annual precipitation (P) and runoff (R) were calculated using rain gauge and hydrometric station records, respectively. Inaddition soil water storage of the catchment was estimated using double ring installation and infiltration rate measures. After determination of annual P and R, the ET component was calculated as the residual of water balance equation. Then the calculated ET was compared with the estimated ET of SEBAL methodology. Comparisons show the adequacy of SEBAL in estimation of actual ET at the studied condition. Finally, the results of the study show that a large portion of catchment available water wastes through evapotranspiration, nearly 540 mm. The runoff and soil storage amounts of the studied year are about 117 and 125 mm, respectively.

The Zayandeh-Rud Basin (ZRB) is expriencing water stress. It has been the situation for the past 50 years. Basin development is considered normally a three-stage process with a relatively smooth transition between overdraft, water supply management, and optimal allocation. In the ZRB however, five phases of water resources developments (WRD) may be identified, including the trans-basin projects. The Situation in the ZRB does not show an encouraging picture. Increased water supply on each phase of development still fall behind the demand growth. That is the reason why for the past 50 years, the basin remained more or less under water stress. There is no inter-basin integrated water management that shares out the shortages uniformly between different uses, or even within a particular water use. Without trans-basin water transfers, the ZRB basin is unable to meet existing water demands. However, several scenarios also show that even then, the basin will be unable to meet water demands before 2020 as long as the urban, industrial and agriculture sectors continue to grow with the current rate.