فهرست مطالب

آبیاری و زهکشی ایران - سال دوازدهم شماره 1 (فروردین و اردیبهشت 1397)
  • سال دوازدهم شماره 1 (فروردین و اردیبهشت 1397)
  • تاریخ انتشار: 1397/02/30
  • تعداد عناوین: 20
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  • Farinaz Shoja Talatapeh *, Davood Farsadizadeh, Ali Hosseinzadeh Dalir, Javad Behmanesh, Mohammad Reza Nikpour Pages 1-12
    Contractions are widely used in channels with supercritical flow, such as water conveyance systems from dams to tunnel spillways, chutes and flood delivery conduits. Technically, production and development of the mentioned waves are undesirable due to water depth increase because of several times increasing of inflow water depth, its spread at a wide range in downstream of channel and water surface roughness. Any weak design of channels under supercritical condition can cause to scour bed and wall the channel, damage to equipment in the flow direction, raising maintenance costs and reduce water conveyance efficiency. In the present research, the formation of shock waves in contractions of open-channel with trapezoidal sections was investigated using experimental and numerical models. The length of transition walls (0.5 and 1m) and angle of side walls (35º, 45º, 60º and 70º) were intended as geometric variables. In different point of shock waves the values of height and instantaneously velocity were measured in the contractions for Froude number and convergence ratio 7.26 and 0.5 respectively. In this research Flow-3D software and in order to simulate turbulent flow, the k-ε RNG model was used. Experimental results showed that increasing the angle of side walls and reducing the length of transition walls caused increment of the shock waves height and velocity. The average relative errors of calculation of shock waves height for different angles: 35º-70º and length of transition walls: 0.5m and 1m were respectively in the range of 4.29-5.06 and 2.28-3.14 percent. Also, the average relative errors of calculation of shock waves velocity for mentioned models were respectively in the range of 3-4.90 and 5.68-7.63 percent.
    Keywords: Instantaneously velocity, Supercritical flow, Trapezoidal section, Turbulence model
  • Samaneh Ashraf, Amin Alizadeh *, Mohammad Mousavi-Baygi, Mohammad Bannayan, Mahdi Jabbarinoghabi, Hossein Dehghanisanij Pages 13-24
    In recent decades, dramatic global population growth along with other related factors such as economic and industrial development, land use/cover change has contributed to an overall effects on water security and environmental problems around the world. To sustainable water management, quantifying the impacts of human activities on local hydrological cycle and water yield is essential in order to control balance between water demand and supply and increasing water security. This paper aims to offer a better characterization of human activities on groundwater stress and sustainability. Herein, we presented an approach for evaluation of water budget to facilitate understanding of the entire flow system of the aquifer in order to inform sustainable water resources management. We used a simple approach for quantifying direct human-hydrologic interactions by analyzing the aquifers’ water budget including human withdrawals (Hout) and return flows (Hin) according to water-balance equation and then normalized them relative to the net flux (Net Flux). Based on the normalized values of human inflow and outflow, the water-use regimes can be classified as surcharged (S), depleted (D), natural-flow dominated (Nf), and human-flow dominated (Hf). In addition we determine groundwater overdraft as a ratio between human withdrawals (Hout) and Recharge (RT) in order to evaluate the flow condition relative to the human water use. Finally we considered two adaptation scenarios to investigate probability of shift of aquifers that are located to depleted regime area to natural-flow dominated area. The results show that half of the studied aquifers in the Karkheh River Basin are of natural-flow dominated type while the rest are depleted. The Asadabad aquifer shows the highest amount (471 mm/yr) of human withdrawals (Hout) in this basin; actually highest overdraft relative to natural recharge to aquifer. Based on investigation of adaption scenarios, we explored that considering adaptation scenarios and decreasing human activities between 10 to 30 percent can be very useful for some aquifers in this basin.
    Keywords: Aquifer, Return flow, Anthropogenic stress, water overdraft, Food security
  • Mohammah Esmaiel Kamali, Alireza Faridhoseini *, Hossien Ansari, Mohammad Ali Gholami Sefidkouhi Pages 25-39
    The determination of maize water requirement and crop coefficient in Babol agrigultural research station in Mazandaran province using Landsat images and SEBAL algorithm was considered in the current study. Therefore, 11 satellite images of Landsat8 and Landsat7 during maize growth period in 2014 and 2015 were prepared. For using SEBAL, each band data was calibrated according to their corresponding coefficients. Then, net radiation flux on the ground surface and soil heat flux was calculated based on input and output radiation fluxes and computation of albedo, surface emissivity, ground surface temperature, and crop indices such as NDVI, SAVI and LAI. Sensible heat flux is also calculated by computation of friction velocity, aerodynamic resistance to heat transport and consideration of cold and hot pixels and atmospheric stability conditions. Finally, maize water requirement maps during growth period were prepared which had RMSE equals to 0.99, 1.09 and 0.65 mm/day compared to Reference Book, National Water Document and FAO56. Then, by computing reference evapotranspiration, maize crop coefficient in different growth stages was determined. This coefficient was 1.24 for mid stage which had 28, 8 and 3 percent difference with Reference Book, National Water Document and FAO56.
    Keywords: Energy balance, Evapotranspiration, Landsat, Net radiation, Sensible heat flux
  • Mohammad Kobarfard, Ramin Fazloula *, Mahdi Zarghami, Abolfazl Akbarpour Pages 40-52
    Due to the complexities of the urban environment, in recent years flood risk in urban basins in comparison with non-urban basins has increased. Flooding in urban areas, causes damage to buildings and other large urban infrastructure and it slow down or completely hinder traffic system. In this paper, urban flood management to reduce flooding low-impact development techniques, using methods such as porous pavement and infiltration trenches are discussed. For this purpose, using the software EPA-SWMM, in an area of Tabriz municipality, a network of surface water collecting was assessed and with four events at the time of simulation model, it was validated and calibrated. The network collects surface water in the three scenarios underlying the adoption of the final version of the LID by hydraulic capacity of streams and reducing peak flood runoff was investigated. The results showed that the majority of the urban network in flood return periods of 2, 5 and 10 years old, storm water drainage do not have the necessary capacity and respectively 28, 45 and 48 percent of the network will be flooded in critical situations. Well as the LID trenches influence over Porous Pavements for return periods of 2, 5 and 10 years old, in the same condition in about 8 to 10 percent better performance in reducing peak runoff from watersheds and reduce flood risk while increasing groundwater is an important breakthrough as the best and most efficient way of management (BMP) for the study area were identified.
    Keywords: Best Management Practices (BMP), Low-Impact Development (LID), Urban Floods, Flood Management
  • Niloofar Falah Rastegar *, Mohammad Hossien Niksokhan Pages 53-62
    Given the rapid growth of the population, The living organism's need to water, significant decrement in safe and available drinking water resources and an unexpected increase in water pollution, it is essential thah water resources ‘quality planning and quantitative controlling’ to be more closely monitored. In this thesis, the Kan catchment located in the northwestern part of Tehran is considered as the study area. in this research, the quantitative and qualitative modeling of the watershed was conducted in 1971-2010 using the SWAT hydrological model, then, the results of the rainfall and temperature outcomes of the HADCM3 model with the AIB scenario for the period of 2011-2030 were extracted using the LARS_WG software. Then the collected data were used as the climate input data into the SWAT model followed by measuring the quantitative and qualitative modeling of the basin for this period in which the qualitative parameter of nitrate were reviewed. The results of the comparison highlighted the fact that there is a significant decrease in the amount of discharge besides an increase in the concentration of nitrate in coming years which could leave a set of destructive effects over the catchment.
    Keywords: Quantitative, qualitative study, climate change, SWAT model, LARS-WG model
  • Sohrab Azizpour, Ali Shahnazari *, Mirkhalegh Ziatabar Ahmadi, Fatemeh Karandish Pages 63-75
    In order to reduce water and chemical fertilizer consumption and improved nutrient uptake in a maize field in Sari Agricultural Sciences and Natural Resources University this research were carried out during years 2015 to 2016. Main plot consisted of irrigation treatment (Full irrigation (FI), deficit irrigation (DI) and partial root zone drying irrigation (PRD)). Sub plot consisted of fertilizer treatment (chemical fertilizer (T1), 50% chemical fertilizer 5.5 tons per ha of vermicompost (T2) and 11 tons per ha of vermicompost (T3)). The result showed that the simultaneous application of PRD and vermicompost save more water. The effect of irrigation treatment on N, P, K, Fe, Zn and Mn was significant but no significant on Cu. The effect of fertilizer treatment on N, P, Fe, Cu, Zn and Mn was significant but no significant on K. There was no significant effect between PRD and T2 treatment with FI and T2 treatment on concentrations of nutrients and yield. Therefore, simultaneous use of partial root zone drying with vermicompost in combination with chemical fertilizers is recommended to achieve sustainable agriculture.
    Keywords: Drough stress, Organic matter, Chemical fertilizer
  • Ahmad Asgari, Abdollah Darzi-Naftchali * Pages 76-87
    Improving soil water situation in the paddies by subsurface drainage systems provides suitable condition for the cultivation of winter canola. In order to evaluate the effect of subsurface drainage on the winter canola growth in paddy fields, an experiment was conducted as split plot in a randomized complete block design with three replications. The main factor involved farm drainage system consists of three conventional drainage systems with 0.90 m and 0.65m depths at 15 and 30m distances (D0.90L30, D0.65L30 and D0.65L15: D and L indicate drain depth and spacing, respectively) and a subsurface drainage system with four drain lines spaced 15 m apart with a depth of 0.65 m and 0.90 m as alternate (Bilevel). The sub factors were also the days after planting. During the growing period, to determine leaf area index (LAI), 1326 canola leaves were sampled and were analyzed by direct measurement and Digimizer software. The DataFit9 software was applied to examine the mathematical equations governing the canola LAI under different drainage systems. Water table rising was affected by precipitation and its falling was related to the performance of different subsurface drainage systems. In this regard, Bilevel system with mean depth to the water table of 64.7 cm had higherLAI. Critical LAI was found in 100 to 114 day after planting and its maximum (4.71) was observed in Bilevel. Even mathematical functions with the orders of 6 and 8 showed more accurate estimation other than equations for LAI in different drainage systems. Base on the results, subsurface drainage with proper depth and spacing could improve canola LAI by controlling the water table below the root zone.
    Keywords: paddy fields, subsurface drainage, mathematical equations, GDD
  • Amir Aazami *, Amir Hossien Alibaygi, Ali Asghar Mirakzadeh, Alireza Darban Astane Pages 88-99
    Undoubtedly, manufacturing and exploiting civil projects such as dams and irrigation and drainage networks have inevitable and unexpected negative effects on the environment and economic and social grounds of a region. Accordingly, in this study, the researcher explores the social effects of irrigation and drainage networks of Kavoshan dam followed by the analysis of users` satisfaction level from these networks.
    Firstly,it was necessary to compare development level of social indicators in the villages under the coverage of drainage and irrigation network of Gavoshan dam and the results showed that village Cheshmeh Kaboud has the highest rate of exploitation from social indicators to use irrigation and drainage networks among 6 villages followed byGoharChegha,Gandab, Siahchegha,Jelogireh and Khoshinanolia.Based on the evidence collected,88% of beneficiaries stated that they benefited from irrigation and drainage networks and 12% did not benefit from these networks.
    The results of investigating the villagers` exploitation from the benefits of using irrigation and drainage networks show that in the importance of priority, increasing revenue through agriculture is one the benefits from the irrigation and drainage networks for 81.3% of the villagers.
    On the other hand, the results of villagers` experiencing the harms of using irrigation and drainage networks show that in the importance of priority , increase of conflict and dispute overed 28% of beneficiaries while others were spared of this harm.
    Keywords: Gavoshan dam, irrigation, drainage networks, social effects, satisfaction
  • Hossien Mojtahedi, Mahmood Maghrebi * Pages 100-110
    The hydraulic gradient at the end of d/s of diversion dams as well as the seepage rate can be controlled by cutoff. In this paper, the hydraulic gradient equations in terms of the d/s distance and seepage discharge have been obtained for an infinite depth of the impervious layer by the use of conformal mapping. Then, they have been used to produce the pertinent graphs that show the variations of seepage discharge as a function of cutoff length and distance from d/s. The results will be useful for the designers of diversion dams. Three scenarios of cutoff walls are discussed: vertical cutoff at d/s, u/s and a couple of cutoffs at d/s and u/s of the impervious floor. The results show that the effect of two cutoffs at the u/s and d/s ends in reducing the seepage discharge is larger than two other cases. Also, for b/S=const., where b is the total length of the impervious floor and S is the cutoff length, the d/s cutoff more effectively reduces the seepage discharge than the u/s one. If b/S=1.5, at x=0.5b from d/s end, the effect of d/s cutoff in reducing seepage discharge is 6% more than the u/s one.
    Keywords: Cutoff- Diversion dam- Hydraulic Gradient- Seepage- Conformal Mapping
  • Mohammadtagi Alami, Habibeh Abbasi *, Mohhammad Hossien Niksokhan Pages 111-118
    The purpose of this study is automatic calibration of water quality model to simulate water temperature. In this study, CE-QUAL-W2 was applied to simulate water temperature in the Alavian dam reservoir located in East-Azarbayjan province. Uncertainty analysis in some models such as CE-QUAL-W2 is difficult and very rare, because of their complexity and high computational cost among other models. Sequential Uncertainty Fitting (SUFI-2) was used to calibrate and analyze the uncertainty of CE-QUAL-W2 model. The performance of SUFI-2 was evaluated using the Absolute Mean Error (AME) as an objective function. Uncertainty statistics used were the and . Model calibration was accomplished during November 2007 to September 2008 and later validated during the period from August 2008 to September 2009. After simulating the water level, the temperature was simulated with an Absolute Mean Error 1.27 and 1.76 ºC during the calibration and validation periods, respectively. The
    have been calculated as 0.53 and 0.4 during the calibration and validation periods, respectively. The results showed vertical temperature profiles of the calibrated model agree closely with the measured data.
    Keywords: Calibration, CE-QUAL-W2 Model, SUFI-2 Algorithm, Uncertainty, Water Temperature Simulation
  • Ebrahim Nohani *, Edris Merufinia, Khobat Khosravi Pages 119-129
    Groundwater is the major sources of fresh water supply for human being. Iran country with arid and semi-arid climate conditions and average annual rainfall of 250 ml is considered as one of the most waterless countries of the world. In this study, the frequency ratio method on the basis of GIS was used for detection and zoning of the Al-shtar plain regions which are potential in terms of underground waters in Lorestan Province. The most initial step is identification of effective factors. So, seven effective factors including gradient, altitudinal floors, land use, curvature of the earth, Standardized Precipitation Index (SPI), Topographic Wetness Index were identified and documented with regard to the resources review. For this purpose, among from the 28 available wells, 20 wells were selected for education and calibration of the model and 8 wells were utilized for validation. The associated map to the 5 classes with so low, low, average, high and very high potential was categorized. According to the performed validation, the frequency ratio model has enough accuracy and it is suitable for preparation of potential detection maps of underground water supply of Al-shtar plain. The results demonstrated that the western and northern edge of the plain have high potential, while the center of the plain has average potential.
    Keywords: Al-shtar Plain, Frequency Ratio, GIS, Potential Detection of the Underground water Resources
  • Fatemeh Hajiabadi, Farzad Hasanpour *, Mostafa Yaghoubzade, Hossien Hammami Pages 130-142
    Drought is a natural and continuous climatic phenomenon which usually occurs in all areas of the world, but its characteristics, type and intensity is different regionally. It is also a progressive phenomenon so that its start and end is not clear and its influence intensity is low but, it encompasses more areas compare to other disasters such as flood, earthquake and etc. which is finally caused more losses rather than other disasters. Drought threshold considering spatial condition is different, therefore, point statistics of one station as an index station of each region is useable for removing spatial effects. In this study, by use of a software which is designed for calculating Palmer Drought severity Index, this index is calculated and presented for Birjand synoptic station during 1985-2014 statistical period in annual and monthly scale. Also, drought process is studied by use of Mann- Kendal and Petit statistical test. Spi drought index is also presented and an analysis has taken concerning drought indexes and relative yield of rain-fed wheat crop relationship by use of Birjand rain-fed wheat yield data during foregoing statistical period. While the air temperature and precipitation data were homogeneous, Based on statistical tests, it was identified that the 30-year period is enough for drought monitoring and analysis. Results showed that sudden changes of annual and monthly spi time series are significant at 5 percent and its change point is May 1998. Also, about annual and monthly pdsi index, results indicate that sudden changes of annual pdsi time series are significant at 5 percent and its change point is February 2000. Spi and pdsi indexes also had a trend consistent with the relative yield crop index of rain-fed wheat and after change point; the pdsi index correlation coefficient was obtained for rain-fed wheat relative yield equal to 0.7 and the spi index correlation rate for rain-fed wheat relative yield equal to 0.55.
    Keywords: Agricultural Drought, Drought Process, Mann- Kendal, Petit Test, Rain-Fed Wheat Relative Yield
  • Sanaz Daei, Meysam Salarijazi *, Khalil Ghorbani, Mehdi Meftah Halaghi Pages 143-152
    The conventional curve number (SCS-CNT) model, which is based on the application of the proposed table by US Soil Conservation Service (SCS), is widely used by researchers and engineers. However, characteristics of the study catchment may be completely different from the conditions for the extraction of SCS-CNT model. Calibrated curve number model (SCS-CNC) can be a solution in this problem. In this study, 37 rainfall-runoff events were investigated in Tamer, Galikesh, Nodeh, Vatna and Kechik catchments (with area 1527, 401.45, 789.65, 10.77 and 36 square kilometers respectively) located in Golestan province, Iran, and 14 events were used for SCS-CNT and SCS-CNC models’ comparison. Results were compared based on root mean square error (RMSE), Nash-Sutcliffe (NSE) and peak discharge estimation error (PEP). The RMSE and NSE criteria in 79% and PEP criterion in 86% of the cases confirmed improvement of the hydrograph and peak discharge estimations in SCS-CNC compared to SCS-CNT model. The SCS-CNC and SCS-CNT models resulted in peak discharge underestimation in 8 and 7 events and overestimation in 6 and 7 events, respectively. Results indicated that application of the calibrated curve number model improves the simulation results in all five studied catchments.
    Keywords: CN, Flood, Hydrograph, Peak discharge
  • Marjan Ghoochanian, Bijan Ghahreman *, Ali Naghi Ziaee, Morteza Sadeghi Pages 153-164
    Infiltration is one of the most important physical parameters of the soil, which plays an important role in the hydrological cycle. The locaton variability in analyzing issues of water flow in the soil, at large levels such as the catchment area, is very difficult and costly. The use of scaling methods is a practical solution to the problems of soil variability. After presenting the theory of similar environments, scaling methods were proposed to overcome the problem of soil variability. In this research, the Richards equation was solved in a wide range of moisture (saturated moisture up to the remaining moisture content) for sandy soil, and the scale of accumulated penetration values was presented using the scaling of the results of solving this equation. These values were approximated with the triple-form of the Philip equation and, using regression models, for each sentence of this equation, an empirical relation was established for water penetration in soil. Then, using two sandy soils and clay in a specific moisture, the experimental effect was measured for both scaled time scales of 0.1 and 0.01 which included short and long periods. Then, using two sandy soils and clay in a specific moisture, the experimental Efficiency was measured for both scaled time scales of 0.1 and 0.01 which included short and long periods evaluated. Of the four available scenarios, the highest mean square error value was obtained at 0.0053 for clay and for long periods of time. cuase to the fact that this criterion was high in relation to other scenarios, the effect of gravity was calculated in long periods of time. The condition of applying the scaling method used in the research is not the effect of gravity on the capillary force. Also, the influence of the proposed relationship with the comparison of field data measured by Barry et al. (1995) on a sandy soil with a fixed height of water on the soil surface of Boehne et al. (1993) using the Rain simulator , Conducted penetration tests on two clay soils under cultured and uncoated conditions was evaluated. The results showed that the aforementioned relationship can provide an acceptable estimate (with the highest root mean square error of 3%) compared to the measured values of water penetration in the soil.
    Keywords: Infiltration, Philips three-dimensional equation, Richards equation, Scaling
  • Maziyar Bahrami *, Ali Mokhtari, Mahdi Bahrami Pages 165-174
    Potential evapotranspiration is one of the most important components in water balance equation in a watershed or a plain. ETP measurement is a costly and time-consuming process. Therefore, remote sensing allowed us to estimate the surface energy considering the energy balance in a small area in order to calculate evapotranspiration (ET). Thus in this study, the Priestly-Taylor equation associated with Landsat 7 and 8 were taken into account for crop ETP calculation. The remotely sensed ETP algorithm was evaluated against four different ETP calculation approaches including radiation approach (Priestly-Taylor), aerodynamic approach, combination approach (Penman), and temperature approach (Hargreaves). These approaches were conducted using meteorological data obtained from seven stations around the Qazvin plain. Results showed that this algorithm could properly estimate ETP, and had the best relationship with ETP calculated from the Priestly-Taylor equation with R2 of 0.95 and RMSE of 0.6. Also, this algorithm could detect the crop on the ground and presented more actual values of ETP compared with ETPs calculated from meteorological data. Therefore, this algorithm could estimate ETP more accurately by distinguishing the dense of vegetation on the ground.
    Keywords: Landsat imagery, Potential evapotranspiration, Priestly-Taylor, Remote sensing
  • Farzad Darvish Mojeni, Saeed Reza Khodashenas *, Abdolreza Zahiri Pages 175-185
    There are numerous investigations, which carried out regarding solution of lateral distribution of flow velocity and flow discharge computation in compound channels. Most of these researches have been in the case of rigid beds. However, compound river channels have alluvial beds and hydraulically have many differences with the experimental channel with rigid beds. In the case of alluvial bed channels due to the interaction effect of flow and bed sediments in main channel, bed forms as dunes develop and change the riverbed roughness coefficient. Furthermore, the flow pattern in compound channels is essentially three-dimensional and hence it is better to use 3-D mathematical models for solution of their hydraulic problems.
    In this study using mathematical model of FLOW-3D, two and three-dimensional variations of flow velocity in straight compound channels with rigid and alluvial beds have been simulated and compared with the experimental data of Wallingford Hydraulic Research. The lateral distribution of velocities and stage-discharge curves from two large-scale trapezoidal chanals including FCF-A with rigid bed and FCF-C with alluvial bed were used in this study.
    The results showed that flow velocity contours and the lateral distribution of velocity obtained by FLOW-3D model have suitable agreement with the experimental data in both cases of main channel and floodplains. The results of these comparisons also showed that the flow rates of the FLOW-3D model are in great agreement with laboratory data, so that the maximum and average of the relative errors of these results for the channel with rigid bed were 5 and 2.7% and for channels with alluvial bed it was 6% and 3.8%, respectively. Finally, the results obtained from the FLOW-3D model with the results of a one-dimensional DCM, SCM, HEC-RAS,COH, WDCM, EDM and the results of the SSIIM model. This comparison highlighted the superior ability of the FLOW-3D model in flow hydraulic simulation of compound channels with rigid and alluvial beds.
    Keywords: Alluvial bed, Calibration, Compound channels, FLOW-3D mathematical model, Velocity lateral distribution
  • Saeed Farzin *, Sayed-Farhad Mousavi, Mohammad Reza Hassanvand, Amir Hossien Salimi, Mahsa Doostmohammadi Pages 186-198
    The occurrence of a problem in each of the water supply network sections due to pressure or velocity fluctuations can cause disruptions in consumers’ regular life. To help avoid these problems, proper design and optimal management of the network is very important. In this study, control of water pressure and velocity to prevent problems in the water supply network is investigated, and hydraulic flow characteristics in pipes are predicted by artificial neural network. In this regard, first, by zoning of Kangavar city in Kermanshah province (as a case study), six zones were identified, based on distribution parameters, the water supply network for the green space of the city, for 10-year plan and target population of 95000, according to working pattern of 22 hours per day and per capita green space of 29.6 m2 at the end of design period was drawn. Then, EPANET software was used to analyze the pressure, velocity and flow in the pipe network. Based on the results, maximum pressure occurred in the 3-3 joint in the third pressure zone, which was about 100 m of water, and maximum velocity in the network was about 1.4 m/s. Also, results showed that the flow rate used for the network is due to the diameter of the pipes and selected paths in different zones in the appropriate range. Subsequently, artificial neural network was trained using the available quantities and the optimal network was selected with a correlation coefficient of 0.87 and 0.85, respectively, for training and testing phases, respectively. Then, the flow velocity and pipe friction-loss were predicted by the optimal network. Results indicated high potential of artificial neural network in analyzing and predicting hydraulic characteristics of water pipe networks.
    Keywords: Artificial neural network, EPANET, Loss of pressure, Kangavar, Water supply network management
  • Hedieh Pouryazdankhah, Mohammad Reza Khaledian *, Teymoor Razavipour, Mojtaba Rezaie Pages 199-208
    Regardingthe climate change and recent droughts, the proper management of irrigation systems and water resources is very important. However, achieving the optimum crop yields due to lack of water requires, the accuracy estimating the amount of water by the plants to prevent water loss and or water stress in plants is needed. In this study, the reference evapotranspiration using lysimeter was measured during three cropping seasons. Applying Ref-ET software, the reference evapotranspiration with 16 empirical equations using meteorological data were estimated, the significant difference between measured and estimated was determined using SPSS software. The empirical equations Hargreaves, Priestley-Taylor and Penman (FAO) were determined as the most suitable methods for the studied area. For the obtained data from two growing seasons and by applying nonlinear regression in SPSS software, optimized coefficients for the two Priestley-Taylor and Hargreaves equations were estimated, and then by using obtained data in the third year, thevalidation was done and RMSE as well as nRMSE values were calculated to assess the equations that for optimized Hargreaves were 0.20 mm/day and 4.60% and for optimized Priestley-Taylor equation were 0.22 mm/day and 4.5%, respectively.
    Keywords: Hargreaves, Non-linear regression, Optimization, Priestly-Taylor, Rasht
  • Mahbobeh Zarezadeh, Saeid Morid *, Nemat Olah Karimi, Kaveh Madani, Farshad Fatemi Pages 209-221
    One of the most important issues to consider in conflicting trans-boundary river basins like Helmand is the potential for agricultural development. This paper evaluates the land use changes between in the Helmand basin between 1990 and 2013 using remote sensing images and an object-based method. The results show the irrigated land area has changed from 10,000 to 18,000 km2 during this period while rainfed areas decreased by 70%. Using the GEOMOD method and Markov chain evaluations, it is projected that agricultural areas can expand up to 25,465 km2, that means an additional 7465 km2 of agricultural land development. Considering water availability limitation, the maximum agricultural land development cannot exceed 4366 km2. The spatial evaluation of this progress revealed that development is mainly expected to take place in the Arghandab and Middle Helmand sub-basins that can seriously affect the river inflows to Iran and threaten the security and ecosystem in the region. However, considering the new policy of Iran on cross-border farming this can be turned to an opportunity for a win-win management of the Helmed trans-boundary river basin.
    Keywords: Helmand river basin, Land use, Object based classification, Satellite images
  • Mohsen Azizi, Ali Shahidi * Pages 222-238
    Determining the protective area of the well is one of the important parts of the groundwater protection policies in order to prevent the health and environmental hazards. In this research, while introducing calculated constant radius method, KLF and Wyssling analytical methods and numerical modeling were used as the most common methods for protective area of the wellin order to compare these methods using data from 6 rings of rural drinking water in Birjand Plain. The results of the study show that the protective area plotted by the calculated constant radius method does not include a significant part of the protective space plotted by the numerical model in the upstream section of the well. In addition, boundaries plotted by Wyssling and KLF analytical methods are narrow and stretched in terms of appearance compared with the boundary of numerical model, and do not cover a significant portion of the numerical modellateral distances and the calculated upstream protective area is always wider than upstream protective area in the numerical model. The best overlapping of calculated constant radius and analytic Wyssling and KLF methods with numerical boundaries occurs with the efficiency percentage of respectively 67.12%, 64.35% and 60.03% for duration of one year. As the travel time increases, their overlapping with the numerical model is reduced. In general, the numerical model is the most accurate method for drawing the protection area of the well, but the use of simpler methods such as constant radius and analytical techniques will have acceptable accuracy in the absence of data, time, capital, and sufficient expertise.
    Keywords: Birjand plain, Numerical Model, Wellhead protection area