مجله آبیاری و زهکشی ایران
سال یازدهم شماره 4 (مهر و آبان 1396)

This study was conducted to investigate the effect of vadose zone modeling on groundwater recharge, and comparing this method with conventional method of ground water modeling. Hence, Neishaboor plain was selected as a case study. MODFLOW-NWT model was chosen to simulate the flow of saturated zone. The UZF package simulates flow through the vadose zone while the RCH package transfers recharge directly to the saturated zone. Recharge defined for the two groundwater models was obtained from the SWAT model. Automatic calibration of the models was done with PEST form2000 to 2010, and verification of the models was done form2000 to 2010. RMSE of the conventional method (RCH package) and modeling vadose zone (UZF) in calibration stage were 1.45 m and 1.52 m, and in verification stage was 1.80 and 1.62 respectively. Results of UZF indicate recharge enter to the saturated zone with 1 to 56 month lag times in different areas. The sensitivity analysis of models demonstrated that the model, which considered UZF, was moresensitive to input parameters. Findings revealed that taking into account the vadose zone in groundwater modeling, can improve performance of the model, and makes it possible to calculate the lag time and part of infiltration that stored in vadose Zone.

To study the effects of urban wastewater of Torbat Heydariyeh city for field experiments conducted. Research in a block completely randomized design with three replications of five treatments of irrigation. The study treatments of well water (control) T1, wastewater T2, combining 50% water and 50% wastewater T3, Irrigation water and wastewater between T4 and the combination of 33% water and 66% wastewater (used farmers) T5. According to the results of research, irrigation traits were significant at the 1% level. The first Harvest performance treatments T1 and T4, respectively, with a weight of 926.7 and 1850 kg per hectare minimum and maximum value, but the second Harvest performance and function and treatment of T3 highest weight of 2580 and 4173.3 kg per hectare and 10 boll weight 44.23 grams, respectively. Treatment control with the lowest first Harvest performance, total yield and 10 bolls weight between treatments was. Treatment T3 with the second Harvest performance, total yield and 10 bolls weight higher than other treatments recommended for cultivation in the region.

Groundwater flow in variably saturated soils is described by the nonlinear Richards equation. The solution of Richards equation using implicit finite volume method produces a system of nonlinear equations, whose resolution demands for the application of an appropriate nonlinear systems solvers, such as the Picard or the Newton schemes. The Picard iterative technique is a robust method, which is convergent at a linear rate while the Newton-Raphson (Newton) method can produce accurate results when using a suitable initial guess and converge at a much higher rate. But since the computational cost of Newton method, due to the calculation of theformal inversion of Jacobian Matrix and partial derivatives is high, this method doesn’t seem to be demanding for the problems with more than one dimension. In this paper, to reduce the cost and time of Newton’s iterations, the mixed form of Picard and quasi-Newton followed by the Broyden method is employed. Therefore the purpose of this paper is first to investigate the effect of three linearization methods on the time of calculation and then to study the accuracy of the proposed implicit finite volume method for solving two dimensional mixed form of Richards equation. For this, data from a test case for a sandy clay loam soil with constant head as a boundary condition and initial moisture close to residual moisture was used. Comparison of the three linearized methods showed that for well selected convergence criterion, Picard/quasi Newton algorithm can dramatically reduce the time of calculations and number of iteration when compared to Picard scheme. Broyden method has a small effect on reducing time of calculation comparing with Picard/quasi Newton method. The performance of the proposed numerical method was then studied for two dimensionalmovement of water in a variably saturated soil using Picard/quasi Newton/Broyden method in comparison with the Warrick’s analytical solution. The results showed that the implicit finite volume method produced a good fit to the analytical solution, so that the RMSE=0.0001 was calculated between the models results and analytical solution on Richards equation.

Soil cardinal temperatures are one of the affective factors on biological properties of crops and highly affect root growth and consequently, water and nutrient uptake. Since soil water content has a considerable contribution in controlling soil temperature, predicting the probable consequences of applying a specific irrigation strategy may help with selecting a suitable method aiming at increasing water and nutrient use efficiency. Therefore, in this research, HYDRUS2D was applied for dynamical assessment of the influence of different irrigation strategies on the spatial and temporal pattern of soil temperature variations and the projected uncertainties through the simulation approach. Simultaneous soil water content and soil temperature data was collected by using IDRG SMS T-2 sensors installed in maize rooting zone under full irrigation (FI), deficit irrigation (DI) and partial root-zone drying (PRD) during 2010 growing season. Simultaneous soil water content and soil temperature data was collected by using IDRG SMS T-2 sensors installed in maize rooting zone. The calibration process was done using the continues data collected after 10 irrigation events in all treatments, and the validation process was carried out using daily variations of soil temperature. Finally, the model uncertainty was assessed by calculating the spatial and temporal error variance. Based on the root mean square error (RMSE) and model efficiency (EF) in the validation process, HYDRUS2D could accurately simulate soil temperature (RMSE=0.02-0.42 oC, EF=0.71-0.92) and the minimum and maximum RMSE in estimation soil thermal regimes was corresponded to FI and PRD treatments, respectively. the lowest uncertainty domain for simulating soil temperature under FI, PRD and DI treatments was observed in 60-80 cm soil depth, and the estimated errors for these treatments were, respectively, 0.6±0.2, 5.9±2.3 and -5.4±2 percentage, respectively. Moreover, the highest uncertainty domain for FI, PRD and DI treatments was corresponded to 20-40 cm, 0-20 cm and 60-80 cm soil depth, respectively, and accounted for 9±5, -0.6±3.04 and 13.7±5.3 percentage, respectively. Based on the results, applying PRD would decrease the number of stress days through controlling soil cardinal temperatures in the domain of 9-28 oC which led to providing a better condition for root growth especially in the soil depths beyond 40 cm.

Due to increasing human activities and its impacts on the environment and water resources, a paradigm shift in hydrological modeling is inevitable. For better modeling of basins’ hydrological behavior, especially with considering the human influences, hydrologist should have an appropriate understanding of the hydrology, models and modeling. By definition, hydrology, which describes the behavior of water above, over and through the Earth, is a multi-disciplinary science which investigates the relationship between the earth and life sciences. There are two approaches for hydrological modeling, Newtonian and Darwinian, based on which the bottom-up and top-down approaches were developed. Considering the pros and cons of each approach, combination of the bottom-up and top-down approaches can help to a better understanding and modeling of the hydrological system of the basins. In this paper, we discuss the novel approach and its challenges in hydrological modeling. Based on the previous studies, we must change our approach to model hydrological systems for a better understanding of the complex coupled human-environmental systems. Emerging the new sciences of socio hydrology and sustainability science indicates the undeniable role of humans in the environment and the importance of sustainable development. To reach a sustainable development, it is crucial to empower the young hydrologists to cope with the new water resources challenges in a changing world by reframing hydrology education.

This study was conducted to study scheduling of single irrigation for rain-fed wheat using crop water stress index (CWSI) for arid and semiarid regions of Honam plain located in upstream of Karkheh River Basin of Iran during 2004-2005. Three cultivated rain-fed wheat were selected to conduct the treatments. Each farm separated to 2 part: (1) rain-fed (2) single irrigation in spring by depth of 60 cm. Application of single irrigation was different in 3 farms which were in heading, flowering, and milk stages accordingly. Soil water content in 60 cm soil depth and canopy temperature in flowering and milk development stages was measured in different times. CWSI was evaluated when upper and lower base line for non-transpiring were determined. Lower and upper baseline for non-transpiring was Tc –Ta = -2.089 VPD 2.28 and 6.2oC accordingly and CWSI and canopy temperature was 0.36 and 26.4. CWSI and yield variation were in 83% agreement. Moreover, wheat canopy temperature and soil water content showed a high agreement (R2) of 0.78.

This study was conducted to investigate the effect of supplemental irrigation and Stockosorb superabsorbent on yield, yield components and water use efficiency in irrigated wheat during 2015-2016 crop years in agricultural faculty of Tabriz University as factorial in randomized complete block design with three replications. Experimental treatments consisted of supplemental irrigation at three levels of without irrigation (I0), irrigation once in June (I1) and irrigation twice in May and June (I2), and the use of Stockosorb superabsorbent at three levels of 0, 50 and 100 kg.ha-1. (S0, S1 and S2). The results showed that supplemental irrigation was significant on all traits at the level of 1%, but no significant effect of superabsorbent was obtained on biological yield. Interactions in the number of grains per panicle, yield and water use efficiency were significant at the level of 1% and in thousand kernel weight and economical productivity at the level of 5%. The highest yield and water use efficiency was obtained from treatment S2I1, respectively, 4.35 ton.ha-1 and 1.20 kg.m-3. The highest yield and water use efficiency were increased respectively by the amount of 2.74 ton.ha-1 and 0.66 kg.m-3 compared to control. The results of the economic analysis showed that superabsorbent consumption without supplemental irrigation has no economic justification in dry land farming of wheat. Considering the economic analysis, treatment S0I1 with 134.8% increase in yield and 94.4% increase in water use efficiency has the best conditions compared to control. The highest irrigation water use efficiency (3.5 kg.m-3) was obtained from treatment S1I1.

The hillslope erosion is known as the first phase of soil erosion at watershed and the most important in semiarid region. Therefore, assessing effective factors on soil erosion and sediment yield such as land cover at hillslope scale can provide new information leading to more effective decision-making. However, very limited studies have been reported to assess the role of land cover on hydrology at hillslope scale using simulation model. The present study aimed to simulation and then analysis the affectability of soil erosion and sediment yield from land cover percentage scenarios at hillslope scale. For this purpose, Hillslope Erosion Model (HEM) was used for prediction of 16 storm related sediment yield in rangeland of Younesi research center, Markazi Providence. The results showed that HEM could successfully predict the soil erosion rate in study area by calibrating soil erodibility parameter with estimate error and CE of 44 and 88 percent, respectively. Then, effects of 3 scenarios i.e. 10%, 20% and 30% decreasing in rangeland cover were simulated using HEM after calibration and validation of the model. The results, also, showed that soil erosion increased about 21%, 45% and 82% in scenario 10%, 20% and 30% reduction of cover, respectively. Finally, results showed that vegetation cover density had significant effect on sediment yield at hillslope scale.

Today groundwater resources play an important role in the water supply of agriculture. Iran is in the semiarid region so evaluation of irrigation that turns into groundwater resources that called the return flow could have a major role in groundwater recharge and must be considered for effective management of groundwater resources. The goal of this study was investigating the effect of irrigation on groundwater recharge by using the HYDRUS-1D model. In this case study, the data were obtained from a complete growing season of maize and wheat which were planted in the Hashtgerd Alborz Province during the years of 20004 2013. Soil moisture and deep percolation were simulated for two different irrigation efficiencies of 60 and 80 percent (equivalent to 40 and 20 percent deep percolation of irrigation, respectively). The results showed that soil moisture advance underirrigation efficiency increased the level of ground water to 1 m. Also the highest percentage of groundwater recharge from irrigation and rainfall was for winter wheat. During the simulation, irrigation efficiency of 60% and 80%, recharge 2.63 m and 1.6 m the ground water level that 14.6 and 10.92 percent are included irrigation and rainfall respectively. The results of this study showed that deep percolation of irrigation and rainfall can recharge and rise of the groundwater level.

Water resources management and planning globally have become a challenging task due to climate change uncertainties. So in the research, the uncertainty of emissions scenarios were investigated in soil moisture estimation during the growing season for wheat in Faroub field of Neyshabour by SWAP model. The Climate data were estimated by ten of AOGCM model and two of emissions scenarios A2 and B for period of future. The Temperature and precipitation data were downscaled by LARS_WG model and was used in SWAP model. The data of soil moisture in depths of 30cm and 60 cm during the growing season of wheat were calculated and compared for periods of baseline and future. The result showed that in the last weeks of growth wheat of Faroub field, the soil moisture for future period was lower than baseline and plant will encounter with the most aridity tension. Also, result of uncertainty bands of emissions scenarios showed that scenario of 2 than B1 have less certainty in estimation of soil moisture for future period during growth weeks.

Energy dissipation structures are device to control of hydraulic jump, in addition to dissipation of water energy. In this research, experimental investigation the effect of cubic roughness was done with staggered and strip arrangements in different angles and rows on jump length and energy dissipation. For this purpose, in laboratory model used from flume with length of 12, width of 0.5 and height 0.7 meters and rough beds placed in downstream of sharp sluice gate. Experiments was performed for Froude number between 4.5 to 9. The results showed staggered arrangement produced better performance compare to strip arrangement in terms of decreasing relative length, moreover, value showed 49 percent, so that percent of decreasing hydraulic jump length for tested rough beds in compare with smooth bed calculated in range of 46 to 54 percent for staggered arrangement and 37 to 46 percent in strip arrangement. Jump relative length (Lj/ y*2) increases for staggered arrangement with increasing Froude number and for strip arrangement the variation of Lj/ y*2 in high Froude number are independent of Froude numbers. The percent of increasing hydraulic jump energy dissipation rate was in range of 19 to 31 for staggered arrangement and 20 to 34 percent in strip arrangement.

The current study attempted to investigate the effects of pricing policy of water irrigation on cropping pattern and water consumption productivity in Ghorveh- Dehgolan plain at Kurdistan province. The positive mathematical programming and maximum entropy maximum were used to analyze data. The 360 farms selected through stratified random sampling for the crop year 2012-2013 that data was collected through interview and filling questionnaire. The results showed that, the policy of increase water price increased the area under cultivation crops with the low need of water or crops with high revenue. Also, the results water pricing policy on water consumption productivity indicators (Employment per Drop, Crop per Drop and Benefit per Drop) showed that water consumption productivity increases. It should be mentioned is Application of the policy caused increase for onion, Garlic and rapeseed crops and decrease for the rest in Net Benefit per Drop index.

In this study the effects of irrigation water from five stations along the river and irrigation water from well water on heavy metals accumulation in rice were assessed. A pot experiment was carried out in a completely randomized design with three replications. Irrigation regimes were flooding, saturated condition, field capacity (FC), 0.8FC and 0.6FC. Pots with Khazar cultivar, being common in the watershed of Zarjoub River, in a silty clay soil were irrigated with six different water sources. The results show that all irrigation water treatments and all irrigation regimes polluted rice grains to copper and zinc, whereas all irrigation water treatments (well and river water) and all irrigation regimes polluted rice grains to lead (having a concentration higher than 0.2 mg/kg). The results show that except for well water, irrigation water treatments (from all stations along the Zarjoob River) did not pollute rice grains to cadmium. Irrigation regimes of 60 and 80 percent of field capacity polluted rice grains to cadmium.

This study analyzes the hydrological impacts of irrigation systems changes in the Ahar-chai basin. For this purpose, a conceptual approach based on water accounting was applied using WEAP model. Hydrological process of the basin in the form of two models of soil moisture method simulated. In the next step, the calibration and validation of models made and the components of the basin hydrologic balance estimated. The results showed that total evapotranspiration was higher in pressurized irrigation than in surface irrigation (26%). Surface runoff during pressurized irrigation period was lower than surface irrigation period (52%), due to reducing irrigation return flow and rainfall. These results show that the surface runoff can be influenced by the type of irrigation and rainfall. In general, the water balance greatly reduced in the basin. The results indicated the negative potential of pressurized irrigation on basin hydrology. Results also showed that WEAP model is able to assess the hydrological impacts of different irrigation systems on basin water resources. To basin water resources management, the water balance accounting methodology should be implemented to avoid misunderstandings about the hydrological impacts of pressurized irrigation, such as unrealistic expectations in water saving in the basin.

Rainfall pattern in any location has its own distribution, while visual analysis of that can lead to subjective and vague statements. So, finding usefull indices which can explain rainfall distribution is an urgent to better interpret rainfall pattern. Some indices are calculated based on the distance between cumulative rainfall curves and the respective theoretical evenness rainfall lines, which join the lowest and highest cumulative rainfall values within the considered period. In present study the relationship between the indices and yield of two major crops (wheat and barley) are evaluated over a 30-year period (1984-2013) in Mashhad. The indices were applied for two periods (the planting to the harvest of crop and critical stage). Critical stage was limited to 30 days from May-Jun. Results showed that both crops were significantly related to ER (the slope of the evenness line) (up to 0.5), while they were not related to UR (uneven distribution index rainfall). When the evenness index was weighted on the mean daily rainfall, the slope of the evenness line declined (up to 0.45). Significant correlations were also found by calculating the indices over strategic short-term periods for crops (up to 0.48), which indicates that how the effectiveness of these indices may be improved by choosing appropriate periods for different crops.

Three-dimensional pattern of flow on ogee spillway and unlimited geometric parameters changing like a change in crest shape, or modification of the approach channel owing to positional geometric qualities may change the flow characteristics on the one hand and the limited information available about hydraulic ogee spillway with curve axis on the other hand, as a major challenge, has led to the use of meta-model systems and data oriented used by researchers. In current study Artificial Intelligence Techniques (Adaptive Neuro-Fuzzy Inference System (ANFIS) and Support Vector Machine (SVM)) were applied to predict the discharge coefficient of the ogee spillway with curve axis and compared to experimental data. For this purpose, the experimental data of the ogee spillway model with varying training wall convergence angles, 0

Drought as shortage of rainfall compared to its long- term mean in a period can be affected by climate change. Evaluationof drought changes can be useful tool for water resources management. In this study, to investigate the trend of drought in Iran, the monthly rainfall data of 119 meteorological stations in 1366-1390 are considered and SPI drought index are calculated based on these data. The Mann-Kendall and Pettitt tests are used for trend and change point analysis. Results of Pettitt test show change points for 42, 27, 35 and 16 stations in spring, summer, autumn and winter seasons respectively that demonstrates disregarding of change point analysis in trend test application can lead to non- negligible mistakes in results. The results of the trend analysis indicate that there are 4, 10, 8 and 9 increasing and 6, 1, 0 and 2 decreasing tren in stations in spring, summer, autumn and winter seasons respectively. Moreover, investigation of spatial distribution show most of stations with trend in SPI index in different seasons are located in west region of the country so that there are decreasing trend in spring and increasing trend in summer and winter while there is no specific spatial pattern in autumn.

Parameters of infiltration equation have fundamental role in evaluation and design of irrigation systems. In fact, it’s essential that these parameters be carefully estimated in order to increase irrigation efficiency. In this research the Elliott and Walker two-point method, Ebrahimian et al. two-point method, Shepard et al. one-point method, Multilevel optimization method and Benami and Ofen advance method were compared with measured data. The accuracy of each one of them in estimation of advance phase in conventional and fixed alternate furrow irrigation was evaluated in a clay soil. For this purpose, furrows with a length of 70 m, width of 0.75 m, and approximate slope of 0.0075 m/m were prepared. These furrows had 0.9 L/s inflow rate in the first irrigation and 1.1 L/s inflow rate in the second and third irrigations. Infiltration in the furrows was measured in the field using the input-output method. According to the estimation infiltration parameters in estimating of the amount infiltrated, The results showed that the Multilevel optimization method and Elliott and Walker two-point method have the least relative error in conventional furrow irrigation (14.9-17.87%) and in fixed alternate furrow irrigation (12.1- 25.92%), respectively. And the Shepard one-point method have the maximum relative error in estimating of the amount infiltrated in conventional furrow irrigation (40.53%) and in fixed alternate furrow irrigation (33.37%). The Multilevel optimization method provided the least (RMSE) in the estimation of the total volume of infiltrated in the conventional and fixed alternate furrow irrigation. In the prediction of advance phase, the Shepard one-point method and Elliott and Walker two-point method had have the lowest standard error (18.71 and 28.91%) for conventional furrow irrigation and (17.51 and 34.4%) for fixed alternate furrow irrigation, respectively. Comparing the results of the Multilevel optimization method and Elliott and Walker twopoint method showed that the percentage difference between this two methods for estimating the volume of infiltration in conventional furrow irrigation is low and just about three percents (3%). Therefore, it can be a Multilevel optimization method for accurately estimating the volume of infiltration in furrow the soil conditions are similar.

Saturated hydraulic conductivity and effective porosity are important parameters in groundwater modeling, water movement in the soil and solute transport. This study aimed to evaluate the accuracy of prediction of these two parameters simultaneously using numerical solution of one-dimensional Boussinesq equations governing the unsteady and saturation flow. In the proposed inverse method the genetic algorithm method for optimization and from control volume method for numerical solution of the governing equation are used. In order to collecting the required data a physical model with the length of 4 meters, a width of 2 meters and a height of 1.8 meters was used and the height of water table was read by 20 observation wells embedded in the model in different times. The value of saturated hydraulic conductivity (k) and effective porosity (μ) was measured directly. The result showed that genetic algorithm is a powerful tool for optimization of inverse method because in this study saturated hydraulic conductivity and effective porosity were evaluated with a high accuracy. Result showed that the height of water table was predicted with reasonable accuracy by inverse method, so that statistical parameters RMSE, MAE, ME, EF are 22, 18, 53 mm and 94 percent, respectively. The result implies that over time caused the used method has high accuracy so the ability to predict in the end times reverse the first time.

The lack of information on the majority of catchment areas has motivated scholars to use spatial analysis of Geographical Information System (GIS) for hydrological studies and potential detection of the groundwater resources. This paper is focused on studying the performance and efficiency of the evidential belief function (EBF) method for groundwater potential mapping in Alshtar plains, Lorestan province. Moreover, parameters of slope, elevation, land use, curvature, Topography Wetness index (TWI) and Stream Power Index (SPI) were utilized. The digital maps of the all parameters were obtained via AcrGIS 10.1 and SAGA GIS 2 software with Raster Format. The geographical location of 28 wells within the region was provided. These points were randomly divided into the groups consist of 20 wells (70%) and 8 wells (30%) for modelling process (calibration) and validation, respectively. The results indicated that the EBF method possesses a proper efficiency for potential detection of the groundwater resources. With regard to the final zoning map, it can be deduced that the western parts of the plain have the higher potential and the center of the plain has the low groundwater potential.