فهرست مطالب

مجله آبیاری و زهکشی ایران
سال پنجم شماره 2 (تابستان 1390)

  • تاریخ انتشار: 1390/08/14
  • تعداد عناوین: 11
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  • A. Dindarlou, A. Kamgar Haghighi, A. R. Sepaskhah, Sh. Zandparsa, T. Honar, A. Dalir, A. Behnamifar Page 158
    The Ordibehesht canal is one of the main canals of Doroodzan Dam, covering 7000ha. In this canal water distribution has been by the volumetric method since 2002. The hydromodule index has been commonly used to evaluate water distribution equity in irrigation networks, and is based on water allocation. In order to evaluate equity in water distribution, among the tertiary canals the hydromodule index was computed as the ratio of delivered water by the doroodzan water district divided by the area covered by each tertiary canal. Following computation of this index, water distributions among the tertiary canals were evaluated. It was assumed that each farming area covered by a tertiary canal would remain constant during all seasons of the year. But in reality winter and summer season crops different cultivation areas, and thus require different quantities of delivered water. As results computed values are higher for summer crops. Application of this index for winter crops showed that equity in water distribution among the tertiary canals was not considered during winter season, to the extent that the index values for the T15, T17, T21 and T24 canals were quite low. But high values were obtained for the T16 and T20 canals. The results indicated about average index value for theT18, T19, T22, and T23 canals.
    Keywords: Ordibehesht channel, Doroodzan Dam, Hydromodul index, Evaluation, Equity
  • A. Kaviani, T. Sohrabi, P. Arasteh Page 165
    The world has finite water resources, which are under increasing stress as the human population and water demand per capita both increase. These problems are not new but are now becoming more widespread and their impacts more devastating. This has provided additional impetus for the search for solutions to problems arising from the mismatch between demand and supply in terms of water quantity, quality and timing. Increasing water productivity has been identified as one of the global challenges that require urgent attention. Agricultural water productivity (WP) between water and food politicians is so important on watershed scale.This concept is a measure of performance expressed as the ratio of dry biomass to actual evapotranspiration in watershed. Remote sensing techniques which used mostly in research on last decade make its use more necessary. This research was conducted on farms which are located on lower part of Qazvin irrigation network. Evapotranspiration and dry biomass were determined using MODIS images in SEBAL algorithm. In this study, five cloudless images were selected which coincided to lysimeter data. Then ENVI model and ILWIS software were used in SEBAL execution of images. Results obtained from of SEBAL algorithm with five images was compared with lysimeter data in each of five days (R2=0.80). This correlation indicates good agreement between SEBAL estimated WP directly derived from MODIS images and lysimeter data. SEBAL estimated WP in Qazvin plain w/o crop consideration was ranged from 0.12 to 1.3 kg/m3. This value for wheat as an indicator in Qazvin plain was 0.76 kg/m3 by SEBAL and 0.9 kg/m3 by lysimeter.
    Keywords: Evapotranspiration, Remote sensing, SEBAL algorithm, Water productivity, MODIS –ENVI
  • A. Alizadeh, M. Erfanian, H. Ansari Page 176
    Rainfall and mean temperature are the most important meteorological parameters in determining distribution of other meteorological variables and also in climatic classifications. In addition, they have undeniable effects on human, natural and especially agricultural activities. Therefore knowing the value, variation and prediction of these parameters could result in precise management in different sectors. This research was done for the assessment of teleconnection indices, which affect the two mentioned parameters in Mashhad during the period of 1956-2010. The stepwise regression model with limited input was used for training and also evaluation data to derive monthly and seasonal prediction models. The statistical results showed that these models have the suitable performance to predict the rainfall and temperature parameters. In general, this performance was more appropriate for monthly models than seasonal ones, and also for temperature than rainfall.
    Keywords: Teleconnection pattern, Rainfall, Mean temperature, Stepwise regression, Mashhad
  • S.A. Heydarian, M. Taleshi, M. Alinejad Page 186

    Process of Irrigation Management Transfer (IMT) is more complicated. Hence, inadequate processis probable. This conclusion refers to FAO research on IMT, within 43 Irrigation networks of 33 countries in five continents. This research identifies the impacts of IMT process on water users’ satisfaction and management improvement in Moghan Irrigation networks. This study focuses on two different levels of ownerships (with less and more than 5 hectares irrigated area). The research method is descriptive-correlation. The population size is 722 water user of 3200 hectares pressurized Irrigation area under Moghan pumping station No.8. Data collected by a questionnaire which its validity was obtained through pre-test. Data analyzed through one sample mean test, Pearson correlation and t-test. This research indicates that Result indicators (=management improvement) of two different levels of ownerships have no sufficient correlation, but in two mentioned levels the Satisfaction and Process indicators had 70% correlation with 90% significant level. Moreover, the mean values of Process indicators in two mentioned levels were higher than expected Mean value. In this case, the Mean values of groups of Satisfaction and Process indicators were also higher. Therefore, this research confirms the direct correlation between Satisfaction and IMT Process, in two different levels of ownerships.

    Keywords: IMT, Process, Management improvement, Satisfaction, Moghan
  • H. Savari, S. Kouchakzadeh Page 194

    The baffle sluice modules are structures designed for delivering rather a constant discharge within a specific rang of upstream water depth variation. They consist of three fixed vertical baffles each has a constant height and constant opening. The height of baffles increases in the downstream direction, but their openings decreased in the same direction. For the modules employed in farm irrigation canals four design methods have been proposed so far. Though the distances between the fixed baffles play an important role in the design process, no agreement among researchers was reported yet. In this research a comprehensive investigation was conducted to determine the proper distance of the baffles. The optimum distance should limit the range of discharge deviation from the design discharge and take into account the construction and installation restriction as well as economic consideration. Also the optimum distance for modules with different discharge is determined and suggested.

    Keywords: Baffle sluice module, Sluice gate, Volumetric water delivery, Turnouts
  • J. A. Palangi, A. M. Akhondali Page 202
    In trickle irrigation, dripper spacing consider on the basis of wetting pattern and wetted area. Then, wetting pattern dimension that is named wetting bulb, is effective parameter in dripper choice and in optimal design of trickle irrigation systems, it is necessary to determinate its amount exactly. In order to study possibility of use of Schwartzan & Zur model to determinate of dripper spacing in trickle irrigation, this research have done in a sandy soil in Albaji region, Khuzestan province, Iran.this model has no suitable efficiency in wetting patterns approximation in this study conditions. so on the basis of measured data, Schwartzman & Zur model was calibrated. With mean relative error of 7%, R2=0.944 and RMSE=5/7 for predicting of wetted diameter and mean relative error of 6/8%, R2=0.914 and RMSE=5 for predicting of wetted depth was successful. Finally, in order to determine dripper spacing in optimal designation and management of trickle irrigation systems and for increase of irrigation efficiency in this study region a table was offered.
    Keywords: Trickle irrigation, Wetting pattern, Dimensional analysis, Schwartzman, Zur model
  • M. R. Keshavarz, M. Vazifedoust, A. Alizadeh, A. Asadi Page 209

    Soil moisture in the root zone is defined as soil moisture in depths of 1 to 2 meter from surface. This moisture is generally available for crop development and can be transported to the atmosphere through evaporation process. Due to the importance of soil moisture for plants growth and in the biology interactions, it is considered as a key factor for agriculture sector. In this research, to evaluate soil moisture routing, Soil Wetness Index (SWI) was derived from reflective and thermal satellite data. For this purposes, 8 day-products of land surface reflectance (MOD09Q1) and LST (MOD11A2) derived from MODIS satellite data over Esfahan in the period of 2000-01(dry year) and 2004-05 (wet year) 8-day time step were used. Trend of soil moisture variations was evaluated using statistical methods such as Mann- Kendall, linear Regression and Wald- Wolfowitz in the 5 percent confident level. The results indicated that in the more than 40 percent of study area, there are no considerable variations in amount of soil moisture. The results showed also that Wald-Wolfowitz is not a suitable method for soil moisture routing in our area. The results indicated that in the western and central parts of study area, number of points with negative amount of moisture trend is increasing (from about 23% in dry year to 53% in wet year). It means that a long term trend of moisture declination and probably drought has occurred in the region. The points with positive trend in amount of soil moisture are limited only in the low eastern parts, Zayande roud river side and Gawkhoni swamp.

    Keywords: Isfahan, MODIS, Remote Sensing, Soil moisture, Trend
  • Y. Ostovari, H. Beigi Harchegani*, A.R. Davoodian Page 242
    Generalizing point measurements of water quality characteristics to maps can be useful for estimation purposes. Interpolation techniques may be used to estimate unknown parameter values. Such characteristics as EC, TDS, turbidity, TSS, pH, and Langelier Saturation Index (LI) play a role in drip irrigation system design. In this study, the spatial patterns of these water quality parameters in the Lordegan plain located in Charmahal-va- Bakhtiari is investigated using geostatistical interpolation techniques of kriging and inverse distance method (IDM). For this purpose 52 agricultural wells, well-scattered across the plain, was sampled four times during year 1389 and relevant water qualities were measured. For all studied parameters, kriging had a lower ME and R2 compared to IDM and was, therefore, selected for mapping. EC values were between 450 to 960 μS/cm that placing water in class C2 and C3 for irrigation. TDS in northern part of the aquifer reaches 500 mg/L which presents medium clogging risk in drippers. LI index was always positive ranging from 0.08 to 0.17 with a mean of 0.12, therefore indicating a slight potential for calcium precipitation in drip irrigation system. The presence of carbonatic geological formations in the plain may be the main reason for positive LI index. Overall, the values of water quality parameters in the northern part of the plain tended to be higher than in the other parts of the aquifer. Therefore, in the northern part of this plain there exist some restriction for drip irrigation and slight risk of system clogging. Overall, the water quality of this aquifer is suitable for drip irrigation particularly in the eastern and western parts of the aquifer.
    Keywords: Water quality, Drip irrigation, Spatial variability, Mapping
  • R. Bahramloo*, S.M. Seiiedan Page 254
    Apply of suitable lining in irrigation canals to enhance conveyance and distribution efficiency, is one of effective methods to control of water and capital losses in part of agriculture.Different kinds of materials were used as lining to control water loss. Therefore its necessary that in different area all various lining are evaluated and suitable lining are chsen based on durability and economic. The aim of this research was to study economic effect of concrete lining in main irrigation canals based on reduction of water seepage loss, area of extentable irrited cultural and extention expence of lining in cold area of Hamadan province. Total length of concrete-lined irrigation canals in this province is 500 km. 12 main lined and unlined canals with total length of 26 km were chosen to study in this area. Water seepage in these canals was measured by the inflow-outflow method. While water velocity was determined using a current-meter. extention expences were determined in unlined and concrete lining of canals. The volume water losses through seepage at unlined and concrete-lined canals was determined 9.4 MCM and 5.19 MCM respectively. So with usage of concrete lining in earth irrigation canals, the seepage water loss has been reduced about 4.21 MCM. With this volume of water about 430 hac. of agriculture areas will be irrigated. Totall extention expences of 13.47 km of concrete lined-canals was 8355 million rials. Benefit-cost ratio in studied unlined and concrete-lined was 315 and 23 respectively. So with usage of concrete lining in earth canals benefit-cost ratio has been redused to 1/14. application of concrete lining in this cold area is not economic. It’s becouse of cracking and destruction of concrete linings in such a this cold climate condition.
    Keywords: Economic evaluation, Concrete lining, Irrigation canals, Cold regions
  • H. Dehghan, A. Alizadeh, H. Ansari, S.A. Haghayeghi Moghaddam Page 263
    Because of the scarcity of water resources in Iran, agricultural water productivity indices measuring and analyzing is very important. Purposes of this study, are to simulate the components of water balance in field level, to predict moisture in soil profile and to analyze water productivity indices in wheat irrigated fields for Neyshabur plain. Three wheat farms were selected at different parts of Neyshabour plain in 2008 2009. All required data for running SWAP model were collected. The model was calibrated and validated for all soil hydraulic parameters and wheat agricultural characteristics in each field, separately. Results show that SWAP could predict moisture profiles satisfactorily, in different times and depths. Water productivity indices were calculated using components of water balance, by SWAP. Averages of these indices that hereafter we called as T WP (yield to crop actual transpiration ratio), ET WP (yield to crop actual evapotranspiration ratio), ETQ WP (yield to crop actual evapotranspiration plus deep percolation ratio) and Irr WP (yield to total applied water ratio) were 1.28, 0.99, 0.6 and 0.88, respectively. According to results of this study, it is possible to increase wheat yield by 14% if irrigation scheduling is planned correctly. Moreover, deficit irrigation by 30% show no significant effect on yield. These results indicate that using a appropriate irrigation scheduling, in addition to reducing consumptive water, ETQ WP and Irr WP indices will increase up to 48 and 61 percent, respectively. High evaporation rete at initial stages of crop growth due to traditional irrigation method, has decreased ET WP by 28% compared to T WP. The ET WP value could be improved employing agricultural practices like mulching or using subsurface irrigation. Decreasing applied water depth did not have notable effect on ET WP and T WP indices, but resulted in increasing ETQ WP and Irr WP values remarkably.
    Keywords: Wheat, Water Productivity Indicators, Irrigation Scheduling, SWAP Model, Neyshabur plain
  • J. Baghani*, Sh. Zarea, H. Sadrghaen Page 276
    In the past two decades, the use of pressurized irrigation methods has many applications to reduce losses and water consumption, increase efficiency and productivity of irrigation water, increase yield and reduce harvesting of ground water resources. To assess the effect of changing irrigation methods, a study was conducted on a number of fields of plains of Mashhad and Fariman in 2009. Results showed that, by changing the surface irrigation methods to pressurize, the average amount of water consumed by agriculture and gardens has decreased 27.5 percent and the weighted average total yield of products, about 36 percent and the average amount of irrigation water use efficiency has increased, 95.1. Using irrigation methods, with positive evaluation and a high rate of economic justification. Removal of underground water resources, 10.9 percent had been killed, but the total surface cultivated fields of study, 1532 ha (14.8 percent) to 1759 ha is reached. Reduce the harvest of underground water resources, often due to discharge from the wells has been reduced and has no connection with the irrigation method. On the other hands, the result showed that, use of drip irrigation at less than 10 ha, (part of a water source),were equivalent to 5.8% of total drip irrigation farm’s area and 39% of total of number of them. This could lead to fragmentation of land covered by a water source. Overall, although changes of irrigation methods were evaluated positively but still are harvested higher than the limit of underground water resources And it has not helping to agricultural sustainability of region And in the not too distant future, agricultural area will be unstable.
    Keywords: Drip irrigation, Surface irrigation, Yield, Water use, sustainable agriculture