فهرست مطالب

  • سال نهم شماره 1 (فروردین و اردیبهشت 1394)
  • تاریخ انتشار: 1394/02/13
  • تعداد عناوین: 21
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  • A. A. Bamdad, V. Rezaverdinejad*, A. A. Ghaemi Pages 1-12
    In this research the performance evaluation of SWAP model was investigated for simulating of soil water content and salinity under farmers management in an arid region located in Larestan region in Fars province. For this reason، all field experimental data such as soil water content، soil salinity، crop and soil parameters، meteorological parameters and quality and quantity of irrigation water were measured from Sesame and Maize pilot fields، for 2012-2013 periods and model was sensitivity analyzed، calibrated and validated. Performance evaluation based on statistic indices indicated that the model has a high accuracy in simulating of soil water content and salinity. The estimation average of root mean squares errors of soil water content and salinity were calculated for Maize، 0. 019 (cm3cm-3) and 0. 29 dS/m، respectively and for Sesame 0. 01 (cm3cm-3) and 0. 63 dS/m، respectively. The average of NSE for soil salinity obtained for Maize and Sesame 0. 89 and 0. 90، respectively. The NSE calculated for prediction of soil water content to Maize and Sesame، 0. 77 and 0. 79، respectively. So as for predicting of soil salinity and soil water content، with saline irrigation water، SWAP is a precision and appropriate model.
    Keywords: Performance Evaluation, Water Balance, Solutes Balance, Larestan Plain, Simulation Model
  • S. Rahnamai-Rahsepar, A. Shahnazari*, M.R. Khaledian, A. Forghani Pages 13-21
    Groundwater resources are the most important sources to supply fresh and agriculture waters. Groundwater contaminations by pollutants cause that the groundwater quality decrease. Heavy metals are one of main environmental pollutants and the concentration of heavy metals is increasing due to agricultural and industrial activities. The objective of this study is to investigate the spatial variability of Pb، Cd، Cu and Zn concentration in the groundwater of centeral Guilan and groundwater pollution mapping in that region. Samples were taken from 50 wells of study area during the summer of 2010. Spatial variability of the data was done by GS+ v5. 1 software. First، the accuracy of Kriging (Ok) and Inverse Distance Weighting (IDW) with different powers (2، 3، 4 and 5) were evaluated by MAE and MBE indices. Then the final maps were presented. Kriging was used to prepare final map of Pb. IDW was used to prepare final map of Cu، Zn and Cd. Result showed that the concentration of Pb and Cd in groundwater of centeral Guilan region were more than the standard values for water and the concentration of Cu and Zn were less than the standard values for water. Also the results showed that spherical and exponential models gave the best result to simulate the variograms and these models can also predict the contamination of other areas.
    Keywords: Inverse Distance Weighting, Kriging, GS+ model, Water quality criteria, Well
  • J. Abedi Koupai*, S. Soltanian, M. Gheysari Pages 22-31
    Soil reinforcement is one of the techniques of dealing with problematic soils like sandy soils. Use of appropriate materials in soil reinforcement، improves the engineering properties and mechanical principles of soil such as strength، stiffness or elastic coefficient، ductility and bearing capacity. Materials for reinforcement include metal، polymer materials and even plants. The present study investigates the effect of poly propylene fibers (6 and 12 mm in length) with different percentages (% 0. 05، % 0. 1، % 0. 15 and % 0. 25) on shear parameters، density specifications and soil bearing capacity. The obtained results analyzed statistically in a completely randomized design، and their mean comparison organized in statistical level of %1 (P<0. 01). Results show that none of the poly propylene fibers have significant effect on optimum moisture and maximum weight per unit volume of soil adherence. While both lengths of mentioned fiber have a significant increase in angle of internal friction، bearing capacity of soil.
    Keywords: Unstable sand, polypropylene fibers, standard density, CBR, Direct Shear Test
  • H. Ansari *, M. Hassanpour Pages 32-43
    In the next decades، rapid population growth، increasing demand of agricultural yield and the standard living especially in the developing countries will significantly reduce water availability for agriculture. Therefore، desirable and optimal use of water resources and increasing agricultural productivity are vital. So، in this research، newly developed sensor has been designed and constructed for determining and monitoring real-time temperature، salinity and water content، with three years efforts from 1390. Environmental data measurement system using the brand REC-P55 in the field experiments showed that this system can record moisture content with accuracy less than 0. 05% and validity less than 0. 5% in different soil textures and depths. Moreover، the correlation coefficient for actual recorded data and REC-P55 one is 99%. Also، according to the capabilities of REC-P55، it was found that soil moisture profiles can be easily created and the results are of a high precision in comparison with the electrical resistance sensor and PR2.
    Keywords: Soil Moisture, Irrigation, Temperature, Salinity, Measurement
  • V. Ghadbeigi, M. J. Monem*, S. M.Hashemy Shahedani Pages 44-53
    Irrigation networks operation is not only affected by water delivery and water distirbution، but also is a function of physical conditions of canals and structures. According to the network physical characteristics variety، identifying those that have more impact on the network performance and degree of their impacts، Provides basis for rehabilitation strategies for existing networks، and appropriate performance-based design approach for similar networks. Applying intellectual data mining methods help the irrigation canal managers in finding out the hidden information. One of the most applied data mining methods is the association rules which have been used in this study to extract the performance patterns. Two groups of data have been used for this purpose، including the operational performance operational indices and the physical parameters of Qazvin irrigation network. In this way، the operational performance operational indices were considered as consequent and the physical parameters were presented as antecedents. Apriori algorithm was used to extract the rules. In single-agent relationship، results indicate that two physical parameters of: distance of off takes from main canal and the type of off-takes; are the parameters affecting water delivery adequacy index with high confidence levels of 44% and 47%، respectively. In addition، water delivery stability index have been influenced by the distance of off-takes from regulating structures. Simultaneous study of several physical parameters on operational indices provides more insights in comparison with single-variable analyses. Therefore، in order to benefit the advantages of association rules method the main affecting factors must be considered together.
    Keywords: Operational Performance, Modernization, Rehabilitation, Irrigation Networks, Data Mining, Apriori Algorithm
  • F. Ahmadi, F. Radmaneh, R.L. Mirabbasi Najaf Abadi, S. Ayashm* Pages 54-65
    In this study، for estimating grass reference crop evapotranspiration using support vector machine (SVM) and genetic programming (GP) techniques، monthly meteorological data of 6 synoptic stations in northwest of Iran during a 38 year period (1973-2010) were collected. At first، the monthly grass reference crop evapotranspiration values for selected station were calculated using the FAO-56 Penman-Monteith equation and considered as the output of SVM and GP models. In the next step، a regression equation was made based on effective climatic variables on evapotranspiration and different input patterns were defined for developing SVM and GP models. Since the relative humidity had the lowest effect on evapotranspiration، it was removed from the model’s input variables. In order to consider the effect of memory of time series in the accuracy of evapotranspiration prediction، the evapotranspiration values with one، two، three، four and five months lag time were used in model’s input patterns. Ten input patterns were made for every model. However، the obtained results showed the high accuracy of both SVM and GP models in predicting monthly grass reference crop evapotranspiration in northwest of Iran، but the SVM method had better performance than GP method. Also، the results showed that if there is no enough meteorological data، the memory of time series can be used for predicting monthly grass reference crop evapotranspiration.
    Keywords: Genetic programming, Memory of time series, Grass reference crop evapotranspiration, Support vector machine
  • Sh.Mirzaie*, M.Zakerinia, H.Sharifan, M.Shahabifar Pages 66-74
    In recent years، the Determination of Crop pattern with purpose the use of Optimum Available resources was considerded by Researchers and governments in order to Increasing the farmers'' incoming. According to the Water Crisis، Factors of production Specially water as the most limitative factor in agriculture should be use Systematic and careful planning. In this study we determine the optimized crop pattern of Golestan dam irrigation and drainage network for maximizing the incoming of formers using of MMAS (maximum- minimum ant system). The Result show that the current cropping pattern is not optimize and with applying out suggested crop pattern، benefit per hectar land of plant would be increased especially in fall and summer cropping. Also the model result showed that in fall cropping because of some rainy days، some allocation of water need of crop would be supplied، And it may be saved up to 75 percent in water consumption with application Suggested cropping pattern that would be around 24. 5 MCM water. In case of Storage The Significant volume of water You can cultivate the More land in summer.
    Keywords: Optimization, cropping pattern, Ant Colony Optimization Algorithm, Max, min nt System
  • M. Arezooman Omidi Langrudi, A. Khashei Siuki*, S. Javadi, S. R. Hashemi Pages 75-82
    Water shortage is one of the society''s problems regarding to population increase and industries development nowadays. In addition to quantity، water quality is of special importance. The quality of groundwater and prevent further contamination، especially in areas where have highly vulnerable aquifers is particularly important. Most of the canals in the Kuchesfehan-Astane plain are no lining and this factor leads to more water waste. High water leakage has the main role of underground water pollution in this region because ground water level is high and the salient farming is the water farming in this region. This article attempts to determine the rate of water leakage from traditional irrigation canals by the Seep w software and regarding this the network parameter was made and added to drastic parameters as the 8th parameter. A new plan was drawn that presented better results regarding to the standard drastic plan. It is realized that the vulnerability rate of NW drastic plan is about 7. 9 percent but in the standard drastic plan is about 1. 67 percent by the comparison of standard drastic plan and NW drastic plan. Correlation coefficient was used for the appropriateness assessment and comparison of two plans (between vulnerability and nitrate density factors) and it was about 40 percent for the standard drastic and 60 percent for the NW drastic that shows the high accuracy of NW drastic plan.
    Keywords: Standard drastic, Drastic, NW, Seep W leakage model, Network Irrigation, Drainage
  • A.Khalili*, H.Khozeymehnezhad, A.Akbarpour, P.Varjavand Pages 83-95
    Gravity current is one of the most important factors in sedimentation and reduction of life expectancy of reservoirs. Forehead part of gravity currents is one of the important parts of these currents that are under influence of many factors. The present research has surveyed the effects of vegetation cover in reducing the velocity of forehead gravity current. To do so، the gravity current is entered the flume with 10، 20، 30 and 40 g/l concentration. Then، vegetation covers with 15 and 20 cm heights and five densities of 0. 6، 0. 8، 1. 0، 1. 2، and 1. 4 percent are located across the currents. Measuring the velocity is done in 6 sections of 5 cm distance. The vertical concentration profile is measured in 3 sections with 1m distance. The results showed that as the density of vegetation cover with different heights increases، the development velocity of current proportion to smooth bed reduces to 13 to 28. 5 % and also the gravity current concentration reduces between 53. 54 to 81. 28 %. The 1. 4% density is the most effective density for reducing velocity and concentration of forehead gravity current. Finally، a relation has been presented for calculating the velocity in smooth bed and the vegetation cover beds with different densities.
    Keywords: Currentflow, Velocity of forehead, Vegetation density, Concentration profil
  • M. Assari, M. Mirlatifi*, M. Akbari, A. Naseri Pages 96-108
    In the present research، irrigation management and water productivity on irrigation and drainage networks of Mirza koochak khan agro Industrial Company is evaluated by vegetation index and soil surface moisture maps resulted from SEBAL algorithm and TERRA-MODIS satellite images. In the first stage، reflection coefficient of ground surface، ground radiation coefficient، vegetation indexes such as NDVI، SAVI، GVI and BGR were determined by data preprocessing obtained from satellite images during growth period for 2 years of 1384 and 1385. Then cultivation area and density were estimated. Using the SEBAL algorithm، elements of energy balance on ground surface and Real evapotranspiration were computed and assumed as the water consumption and relative supply of water. Biological production of sugarcane obtained using the average daily solar radiation and fraction of photosynthetic absorbed radiation is determined in form of BGR index and assumed as a symbol of production. Water productivity is resulted from the ration of biological production to real evapotranspiration. Process of seasonal variation is gained for biological production، vegetation index and evapotranspiration. Studying of water supply and demand presents no lack of water in this network and the fraction of overflow is used for salt leaching in soil profile. Average water productivity for biological production in this network for two years of 1384 and 1385 is 4. 24 and 5. 32 kg/m3. In addition، relative water supply for these two years are 1. 67 and 1. 73 respectively. Results of this study، suggests the application of this method for water productivity evaluation in large scale irrigation and drainage networks.
    Keywords: vegetation index, SEBAL algorithm, water productivity, MODIS sensor
  • N. Abbasi* Pages 109-119
    In spite of that، there are variety of construction materials and methods for lining of irrigation canals، cement concrete is the most common construction material used for canal lining in Iran. However، due to high costs of preparation and application of cement concrete and its sensitivity to technical criteria such as mixing design، executive and curing methods، and impossibility of total observance of such criteria in small projects e. g. canal lining، an feasibility study of the use of alternative materials is inevitable. So، in this research using of precosted sulfur concrete tiles for lining of irrigation canals was investigared. Sulfur concrete is made up of molten sulfur and sulfur modifier additive، fine and coarse aggregates which results in a hard material similar to cement concrete that can be used as a construction material. For this purpose، a small canal with a length of 60 meters was constructed and lined using sulfure concrete tiles. Then the seepage losses and roughness of lining were evaluated. Based on the results of the investigation، the seepage losses and Maning coefficient of lining were determined about 0. 14 m3/m2/day and 0. 013 respectivly. Also lake of improper equeipments for construction and application of sulfur concret was determined as the main excutive problem in lining of small irrigation canal using sulfure concrete tiles.
    Keywords: Water conveyance, Hydraulic structure, Maning coefficient, Seepage losses
  • A. Ahmadinik, A. Rahimikhoob* Pages 120-130
    The more accurate estimate of evaporation in Solar Stills is considered as an important step in the planning and design of condensation irrigation system in hot and dry region. Since received radiation to evaporation surface is different inside and outside the Still، to initial estimate of evaporation in Stills، can not apply the commonly techniques used in open surface water. The main purpose of this study is modification of Penman model (as a compound and base model to estimate evaporation from open surface) radiation component and Priestley – Taylor model (as a recommended radiation model for estimating evaporation from closed environments such as greenhouses) to estimate the evaporation rate from the Solar Stills. Comparison of measured and estimated values over the one-year period of the study showed that modification the radiation component have a positive effect in more accurate estimate of evaporation from Solar Stills. The results showed that the modified Penman model is capable of estimate evaporation from Still with R2 0. 950، MBE= 1. 116 (mm/day) and RMSE=1. 258 (mm/day).
    Keywords: Condensation Irrigation System, Desalination, Penman model, Priestley – Taylor model, Saline Water, Solar Stills
  • S. Seifi*, A. Alizadeh, K. Davari, M. Banayan Aval Pages 131-142
    A significant part of Iran lays in arid and semi-arid regions، that face with drought and salinity. In other hand، Water use efficiency under this condition is generally low. Mathematical models that simulate transpiration of plant as a function of soil moisture availability are useful tools for water productivity management. Various mathematical models have developed to estimate transpiration of plant reduction due to combined effect of drought and salinity stresses. This study compares six different macroscopic reduction functions; namely: Van Genuchten (additive and multiplicative، 1987)، Dirksen & Augustijn (1993)، Van Dam et al. (1997)، Homaee (1999) and Skaggs et al. (2006). These models were evaluated against measured transpiration of turfgrass (Lolium prenne) in greenhouse environment for 12 treatments. The factorial experiment was performed based oncompletly randomized design with four levels of salinity (0. 5، 5. 5، 7. 5 and 10 dS/m) and three levels of drought (water refills of 100، 75 and 50 %FC) and three replicates for each treatment. The results indicated that the crop response to water and salinity stresses is additive in low salinity level and is multiplicative at salinity level above 5. 5 dS/m. Among used models، reduction functions of Skaggs et al، Homaee and Van Genuchtenshowed better agreement with the measured data.
    Keywords: Drought Stress, Lolium prenne, Water Uptake Model
  • Kami Kaboosi* Pages 143-151
    In the current study، the effects of hysteresis on calibration curve of gypsum block affected by soil texture and compaction were investigated. For this، calibration curve of gypsum block in 3 soil texture including Sandy Loam، Loam and Silty Clay in three bulk density (natural in the farm and plus 10% and minus 10%) for two phases of wetting and drying were provided. The results showed that block calibration curves were different in two phases of wetting and drying in the different soil compaction and texture. By reducing soil compaction، hysteresis and its effect on shape of calibration curve of block were increased because of fine pores reduction and more non-uniformity of soil pores distribution. The effect of soil compaction on block calibration curve was different during drying and wetting phases such as for specific soil moisture، with increasing soil compaction، the block electric resistance increased and reduced during drying and wetting phases، respectively. During drying and wetting phases، increasing of soil compaction caused 16% increase and 3% decrease in field capacity، respectively. Accordingly، it is recommended that soil compaction of installation place of gypsum block and around be equal.
    Keywords: Bulk Density, Gypsum Block, Hysteresis, Soil Compaction, Soil Moisture
  • S. Akhavan*, V. Afshar, F. Soroush Pages 152-162
    The objective of this study was to investigate polyacrylamide (PAM) application and alternate furrow irrigation system on soil erosion. The study was conducted in Dastjerd Research Farm، Bu Ali Sina University، Hamadan، Iran. The experiment was designed as factorial، based on completely randomized design with three replications. Treatments were conventional furrow irrigation without PAM application (FS 0)، conventional furrow irrigation with PAM application (FSP1. 5)، alternate furrow irrigation without PAM application (FAP0)، and alternate furrow irrigation with PAM application (FAP1. 5). The results showed that there is significant difference (p-value <0. 01) in soil losses in alternate furrow irrigation treatment and PAM application (FA P1. 5). The FA P1. 5 treatment، in comparison with FSP0، lead to reduction of soil losses by 98، 98 and 99 percent in the first، second and third irrigations، respectively. Also، the shape of cross section of furrows didn’t have too much change in treatments with PAM application rather than without PAM application treatment. In general، PAM application could cause stability in soil and cross sections of furrows.
    Keywords: Furrow cross section, Sediment, Soil losses, Surface irrigation
  • H.Sharifan*, M. Kazemi Hasanvand Pages 163-169
    The shortage of suitable quality water resources is becoming one of the main challenges in arid، semi-arid، and coastal zones، sorghum yield declines with an increase in salinity، but its Sensitivity to salts varies with the salt composition in Water and the plant growth stage. The possible use of the Caspian Sea water، which its salinity is well below that of open seas، is desirable for irrigation. This research was conducted to study the effects of salinity levels and irrigation levels and determine the most appropriate mix of sea water and drinking water on yield and yield components of sorghum in research field experiment at Gorgan University of Agricultural Science and Natural Resource during 2012-2013 growing season. A factorial experiment was conducted using a randomized complete block design with four replicates. Salinity levels were S1، S2، S3، S4، S50%، 25%، 50%، 75%، and 100% mixture of Caspian Sea water and well water) and three irrigation levels included as A1، A2 (1. 5*A1) and A3 (2. 5*A1) crop water requirement. The results showed that there was a significant difference in plant height، tiller number، shoot weight and leaf weight per plant (1% level).
    Keywords: sorghum, Sea water, salinity, yield, Caspian Sea
  • M. Abdollahi-Siahkalroudi*, J. Nikbakht, M.H. Mohammadi, M.R. Khaledian Pages 170-179
    Having proper information of the wetted width and depth of soil for the appropriate design and management of a drip irrigation system is essential. This research was carried out to calculate the wetted depth and the maximum wetted width in both surface and subsurface drip irrigations with normal and magnetic waters. Measured values were compared with linear and nonlinear regression and neural network models. Experimental measurements were done on a clay loam soil in the greenhouse of Zanjan University. The results showed that the simple linear and multiple regression for Schwartzman and Zur (1986) and Mirzaei et al 2008) to estimate the wetted depth in surface drip irrigation with normal water was better (r=0. 988 and RMSE=0. 011 m). The difference between the estimated values using Schwartzman and Zur (1986) and Mirzaei et al (2008) in the wetted depth with magnetic water in surface drip irrigation (r=0. 974 and RMSE=0. 014 m) and the maximum wetted width in surface drip irrigation with normal water (r=0. 950 and RMSE=0. 028 m) and with magnetic water (r=0. 976 and RMSE=0. 023 m) with the observed data was minimal. Among the artificial neural networks models used in this study، multilayer perceptron model as compared with radial basis function model performed better.
    Keywords: Artificial neural networks, Drip irrigation, Normal water, Magnetic water, Regression
  • M.J. Nahvinia, A.M. Liaghat*, F. Abbasi Pages 180-194
    Diagnosis of water management at the irrigation district level is required for therational modernization of the irrigation schemes and the subsequent increase in the efficiency of water allocation and application. The objective of this study is to evaluate globally in 3079 ha of land under modern irrigation system Hamody. The main district’s water inputs (irrigation، precipitation and canal releases) and outputs (actual evapotranspiration of crops، outflow surface drainage and canal seepage) were measured or estimated during the 1385 to 1388 hydrological years. The annual average water outputs were 16% higher than the corresponding water inputs، presumably due to canal seepage and lateral groundwater inflows from neighbor dry-land watershed. The district-level irrigation performance was poor (mean 1385-88 seasonal irrigation consumptive use coefficient- ICUC were equal 44%)، due to the low distribution (68%) and on-farm (53%) efficiencies for the 1385-88 irrigation seasons. Thus، despite the high volume of applied irrigation water، the actual district ET was 19% lower than the maximum achievable ET، indicating that the water-stressed crops yielded below their maximums. The evaluation by using neoclassical approach indicated that the values of net (0. 77) and effective efficiency (0. 65) were more than classical efficiency (0. 53)، in surface irrigation systems. The results obtained in this study showed that effective efficiency has suitable expression about irrigation management and method at farm scale، whereas net efficiency only considers concept of reuse of beneficial losses on spatial scale larger than the field. Potential reductions in water allocation were analyzed for three ICUC values (65، 75 and 85%) and two scenarios of modernization (I and II). In scenario I، where the aim was to achieve maximum ET and crop yields، water allocation could be reduced from 0 to 23% of the current allocation. In scenario II، where the aim was to achieve the maximum conservation of water under the actual ET and crop yields، reductions in water allocation would be much higher (from 31 to 47% of current allocation). Thus، significant volumes of water could be conserved in the rehabilitation of this district by increasing the distribution efficiency and، in particular، the onfarm irrigation efficiency.
    Keywords: Systemirrigation, Irrigation efficiency, Irrigation consumptive use coefficient, Water conservation
  • K. Khalili, M. Nazeri Tahrudi, F. Ahmadi* Pages 195-208
    Evaluation of the rainfall phenomenon is important as the most effective meteorological factors that influence the access to the water resources directly. In this research precipitation concentration index (PCI) calculated using of monthly precipitation time series of 34 synoptic stations in the recent half century (1961-2010) and their trends in two annual and seasonal scales investigated. The results of the zoning the mentioned index in annual scale showed that concentration of the precipitation in two 25 years time reach followed from the same pattern. Also results of PCI index showed that rainfall was scattered irregular in the center and southern regions of Iran in the Kerman، Bandar Abbas، Yazd، Zahedan، Shahrekord، Birjand، Bushehr، Ahwaz and Isfahan also in none of the mentioned stations uniform concentration (PCI <10) were not observed in the annual time scale. Results of winter trend investigation of PCI index in the period of 1961-2010 showed that non significant upward and downward trend occurred for the number of sixteen and fifteen stations respectively and in the Dezful، Saghez and Hamedan stations significant decreasing trend observed. Also in the spring season، PCI index results showed significant increasing in the PCI trend for two Kerman and Ramsar stations which means that scattering rainfall was irregular significantly in two mentioned stations. In summer، the Gorgan station showed high irregularity as the PCI index and in autumn، the Tabriz and Zahedan stations showed significant increasing trend while decreasing trend detected for Bablosar station. In annual scale about 50 percentages followed increasing of PCI index values.
    Keywords: Iran, Precipitation Concentration Index, Trend, Mann, Kendall
  • M. Khoshravesh*, M. Raeini, E. Nikzad-Tehrani, A. Koulaian Pages 209-220
    Urbanization development and residential constructions cause permanent changes in agricultural land use features. Therefore the outcome of these changes is an increase in impervious areas in cost of farm lands and natural resources ecosystems، which in turn results in devastating urban runoff. To reduce the cause of urbanization it is inevitable to control، conduct and manage urban flooding. Therefore، the aim of the present study is to assess the impacts of urbanization development on the watershed runoff of Sardaabrud basin، Kalardasht، using HEC-HMS hydrological model. Using the most recent satellite images the residential land areas in the sub-basin were determined. Results show that residential area in downstream of sub-basin (S2) has remarkable growth in compared to upstream sub-basin (S1). Residential area in S1 sub basin includes 0. 3 percent of total area، while in S2 sub-basin it took 8 percent of the total area. Four flooding events were employed to analyze the sensitivity of the model. Results showed that initial loss has high sensitivity compared to the other parameters. Based on this finding the model was validated. The RMSE، t test and correlation coefficient (r) values were acceptable for peak flow in model simulation. Finally، in order to determine the impacts of urban area on watershed runoff، the thunderstorm characteristics were estimated based on intensity – duration. For this purpose the frequency analysis of rainfall data was employed using extreme value type 1 and its curves for 2، 5، 10، 25، 50، 100 years return period. The results show that 25 years flood for S2 sub-basin is almost 4 times of S1 sub-basin. The potential runoff producing of the S2 sub-basin has increased compared to the S1 sub-basin، which is due to development of residential areas.
    Keywords: Urbanization development, Urban runoff, Rainfall, runoff model, Sardaabrud river
  • M.I. Kamali Pashakolaei*, A. Faridhosseini, H. Ansari, M. A. Gholami Sefidkouhi Pages 221-232
    Evapotranspiration (ET0) is a basic parameter for determination irrigation program which has to be estimated using interpolation methods due to its spatial variation. A factor which can affect interpolation results is interpolation stages sequence. Current study was conducted to compare two ways for preparation of spatial distribution maps of ET0. In the first way، ET0 was calculated using climatic data and Hargreaves-Samani method in weather stations positions and then were interpolated. In the second way، the Hargreaves-Samani equation components are firstly interpolated and then ET0 maps were produced by proper commands in GIS. So، 10-year climatic data (2001-2010) of 46 stations for preparation the maps and 5 stations as validation stations in Mazandaran province were gathered. The data were interpolated using Ordinary Kriging method and the interpolation error was compared using Root Mean Squared Standardized Error (RMSSE). The results showed that the temperature data has better spatial correlation and lower interpolation error. But for estimation verification، ET0 amounts derived from the two ways were compared to the computed ET0 in validation stations positions and showed that the two ways difference was not significant. So، these two ways have not differences for producing ET0 maps.
    Keywords: GIS, Interpolation, Ordinary Kriging, Reference evapotranspiration, Spatial distribution