Iranian Journal of Irrigation and Drainage
Year:2015 | Volume:9 | Issue:2|Papers Count:20

Due to the limited water resources in arid regions, using modern irrigation methods with high efficiency in agriculture is essential. One of the methods for increasing water use efficiency is the pitcher underground irrigation method. A proper design of these systems requires the enough information about water flow distribution pattern in both horizontal and vertical directions. Since the field experiments for detecting soil moisture distribution pattern is very hard and time consuming, analytical methods can be used to reasonably estimate the distribution of moisture in the soil though soil water flow equations having soil water factors. The aim of this study was to investigate the moisture distribution pattern in soil using three different heights of irrigation water source (i.e.1, 1.5 and 2 meters) in the certain time intervals. This study was done in a randomized complete blocks design with three replications. Volumetric soil moisture content within 1m-soil profile was measured by TDR. Simulation of water movement in soil was performed by HYDRUS-2D and the simulated values were compared with the measured values at the end. The results show that the model can simulate moisture variation trend with a relatively good accuracy. In the early stage of irrigation, simulator overestimated the moisture content. Moisture variation was not too much at distance 30 cm from vertical axis of the pitcher. This was confirmed by HYDRUS-2D simulated values.The best simulation results were obtained for the 10 cm distance from the vertical axis of pitcher where ME, RMSE and R2 were 0.0015, 0.018 and 0.95, respectively. Moreover it was observed that there is no significant difference between soil water distribution pattern obtained for two water supply elevations of 1.5 and 2 m above the soil surface. The results indicated that HYDRUS-2D can effectively use to simulate soil water distribution pattern under a porous clay pitcher irrigation system.

This main purpose of this research was to investigating of farmers ' knowledge level about agricultural water management technologies in Falavarjan country. Statistical population of this study was consisted of 20156 farmers; out of which 205 people were selected as sample using multi-stage sampling technique. This research was a sort of survey studies and a questionnaire was used for collection of data and information. Questionnaire's reliability was confirmed through computing cornbanch's Alpha coefficient which was more than 0.70. Face validity of questionnaire was confirmed by a panel of expert judgment. Correlation analysis findings revealed that there were significant relationships and positive among farmers' knowledge of agricultural water management technologies and other variables such as "used of information resources", "contacts of extension agents", "attitude of impacted of irrigation systems" and "degree of education", "application of agricultural water management technologies" and negative among "age" and "water scarcity". Regression analysis findings revealed that there were relationships both farmers' knowledge of agricultural water management technologies and "used of information resources", "attitude of impacted of irrigation systems", "water scarcity", "degree of education" and "contacts of extension agents". Also factor analysis results of farmers' knowledge of agricultural water management technologies revealed seven factors totally they explained 56.19 percent of total variance.

To design drip irrigation system, the distribution and changes in soil moisture should be determined in situ that it is very costly and time consuming. This study evaluated the performance of HYDRUS-2D model to estimate soil moisture after irrigation under subsurface line source was in a heterogeneous heavy soil. Irrigation was done at three tape installation depths of 10, 20 and 30 cm with three volumes of 10, 15 and 20 litters in silty clay soil with three repeating. Observed and simulated data were compared using statistical indices i.e. RMSE, nRMSE and CRM. Results showed that the minimum and maximum of RMSE values were 0.013 and 0.045 cm3.cm-3, respectively. nRMSE of all treatments except of one, the second replication of 10 liters of irrigation water with installation depth of 20 cm, were less than 10% categorized in the excellent class of soil moisture simulation. Maximum and minimum values of CRM were 0.100 and -0.065, respectively. Results from the model showed this model can be used in the design and management of subsurface drip irrigation systems in heterogeneous soils with heavy texture.

In this research, five-drip irrigation systems were selected in Sattarkhan Channels Network and technical performances of them were evaluated. In each system one manifold was randomly selected and four located lateral pipes, at the beginning, one-third, two thirds and end of each manifold were selected. By considering the same proportionality, four apple trees were identified a long each lateral pipe. Emitter discharges of two drippers at each of these trees, pressure at the beginning and at the end of the lateral pipes were measured in the all selected manifold pipes. Also, the minimum lateral inlet pressure at each manifold was identified by measuring the flow pressure of the all lateral inlets. Results showed that the water Emission Uniformities of the systems (EUs) were within the range of 48.1 to 82.8 percent and the systems performances based on this index were classified poor to good. Potential application efficiencies of the low quarter of the systems (PELQs) were varied from 43.3 to 74.5 percent. So that, only the irrigation system at one of the farms had relatively good performance and the systems' performances in the other farms were poor. Application efficiencies of low quarter of the systems (AELQs) were in the range of 52.7 to 80 percent. Based on AELQs index, only one system had good performance while the performances of the others were poor. In general, the reasons for the low system performances were pointed as inappropriate distribution of pressure, high-pressure difference in the systems, the unsuitable irrigation water depth, low skills of irrigators and poor operation management of the systems.

The objective of this study was to determine the efficiency of the evaluation criteria for comparison some of soil water retention curve models. For this purpose, 70 soil samples were taken from Karaj, Urmia and Shahrekord plains. The soil Water retention curves were obtained using the result of the pressure plate device.Then, the mean of coefficient of determination (R2), the adjusted coefficient of determination (R2 adj) and root mean square error (RMSE) were calculated for each model and the efficiency of these criteria at the evaluation of mentioned models tested with statistical methods. Then, Akaike’s information criterion and Mallows criteria were used for comparison of reference model with other models for each soil. Difference the mean of R2, R2 adj weren’t significant for all soils and textural classes and for RMSE weren’t significant in six classes from eight textural classes (clay and silty clay) at among of the five models. So, R2, R2 adj and RMSE were not suitable criteria for the selection of optimum model (P≤ 0.05). According to Akaike’s information criterion tests Gardner, Pereira and Fredlund, Khlosi and Van Genuchten- Mualem models for 27.1, 10, 45.7 and 68.6% soils and on the basis of Mallows statistic mention models for 34.3, 10, 48.6 and 71.4% soils were better than the Van Genuchten model, respectively. Additionally, Van Genuchten, Van Genuchten- Mualem and Pereira and Fredlund models had the exact prediction from saturation moisture, but Gardner and Khlosi models had larger errors.

In order to evaluate the performance of the CERES-Rice model in rice biomass and grain yield estimation in large scale, this study was carried out in paddy fields of Guilan, Iran. First the model was calibrated and evaluated using data from a research at Rice Research Institute of Iran, then the model accuracy was assessed in 26000 ha of Some Sara region.110 common farmers fields were chosen, the soil, water, crop samples and other needed information were taken. The model was ran for each field. The results showed that the Error of yield and biomass estimation in research station were below 10 percent. The results in large scale showed that the model estimation of yield and biomass could be categorized in three different parts. While in fields with average biomass and yield observation the setimation error was negligible. Underestimation was observed in the fields with the yield above the average of the region while in high yielding fields overestimation was observed. The Normalized Root Mean Square Error was about 22.7 and 21% for biomass and yield prediction. Although in some cases the error was about 50%, in 75% of the region it was in range of 0-10%, and in 95 % of the region it was in range of 0-20%. Water productivity based on water used in most of the fields was in the range of 0.5-0.6 kg/m3 and the water productivity based on transpiration was 0.85-0.9 kg/ m3. The model showed a satisfactory accuracy to estimate both yield and biomass in large scale paddy fields.

Agriculture as the largest consumer of water, compared to other sectors, is faced with more challenges due to lack of water and the gap between supply and demand for water. The aim of this study is to identify the effective factors on irrigation water demand at farm-level. Data was collected from farmers of Mashhad-Chenaran plain by stratified random sampling method in 2013. The discriminate analysis was used to recognize effective variables on dividing farmers in two groups, low and high water consumption. Result showed that the most important of effective factors to distinguish farmers’ treatment to use of water at farm-level are crop, water saving, income of the farmer, soil texture, experience, education level and flow rate of water taken with correlation coefficients 0.69, 0.3, 0.28, -0.25, -0.22, 0.19 and 0.16 respectively. Also, the results indicated that the value of Lambda Wilkes of discriminant equation to distinguish low and high water used is equal to 0.61 that is significant at 99% level of probability. According to the results, raising awareness of farmers coupled with increasing facilities to improve water saving technologies and subsidizing for low withdrawal of water from wells, can be useful for efficient use of water, use of assessing tools, control the amount of irrigation water applied in farm and correct implementation of modern irrigation systems in the study area.

Soil hydraulic conductivity and water retention curves are the most important factors that effect on water flow in soil. The aim of this study is investigation the effect of land use changing on soil hydraulic properties.Tension disk infiltrometer was used for measurement of in situ soil hydraulic properties. Infiltration experiments were conducted at 3 land uses (including range, Horticulture and Agriculture lands) in 5 tensions (including 0, 3, 6, 10, 18 cm H2O) and 3 replications for each land uses. Horticulture and Agriculture land use have been created of rang land use changing. Hydraulic conductivity and water retention curves were simulated by inverse method using Hydrus 2D software and 3 model of Rosetta, then compaired with observation data. Results showed, SSC+BD is the best model to predicting hydraulic conductivity curve in all 3 land use. Simulation of water retention curve showed, for all 3 models of Rosetta (including Textural class, SSC and SSC+BD), GMER parameter was less than 1, for therefore, inverse method underestimated the water content. Statistical parameters amount showed, in range land-use textural class model, in horticulture land use SSC model and in agriculture land use SSC+BD model are the best models for simulation retention curve. RMSE and MAE amounts for mentioned land uses and models are 0.055, 0.048 (range land use), 0.046, 0.03 (horticulture land use) and 0.05, 0.041 (agriculture land use) respectively.

In many countries across the world, surface irrigation is one of the most important and most common ways to irrigate the fields. So paying attention to improving surface irrigation methods and increasing their efficiency looks necessary. Thus the best design approach is optimized design in which the considered efficiencies in their linear combination are optimized in one goal function. So the purpose of this study is using Sirmod Model, artificial neural network and honey bee mating optimization algorithm for simulation and optimization the surface irrigation parameters like furrow length, inlet discharge and cutoff time. The obtained results showed that the artificial neural network with high R- square for all the outputs has a good ability in simulating surface irrigation’s systems which is so much depended on the variety of the data bank and proper training of the network. Also linking neural network and honey bee mating algorithm in order to develop a simulationoptimization model provided acceptable results which can be used as optimal values in designing. The average values of optimizing design parameters are 202 meter for furrow length, 2.13 liter per seconds for inlet discharge and 28.6 minutes for cutoff time.

Curved weirs in plan due to their special hydraulic conditions as well as long crest, have suitable capability in effective water surface regulation in irrigation canals and networks. Also, these weirs have high turbulence intensity in downstream and make better conditions for rivers, in environmental point of view. There are few studies regarding calculation of curved weirs’ discharge coefficient and their head-discharge equation. In this study, using new optimization method of genetic programming, a dimensionless equation for discharge coefficient has been proposed based on two non-dimensional parameters of weir angel and ratio of water head to weir height. For training and testing of the proposed equation, experimental data of Kumar et al, have been used.Comparison of results obtained from this equation with the experimental data reveals high accuracy of the new equation of genetic programming. Mean absolute errors of the proposed equation for discharge coefficient have been calculated as 1.36 and 1.65 percent, for training and testing phases, respectively. This error for non-linear equation of Kumar et al, is nearly 9.4 percent.

Underground water resources is One of the most important parts that supplies the human need, particularly in arid and semi-arid. At present, a considerable part of the drinking water is supplied from underground water sources, which are mostly free aquifer. Therefore, the Quality protection of this sources is important.Decontamination of groundwater is costly and lengthy process and is often diagnosed when the aquifer decontamination is impossible. Identify vulnerable areas of aquifers and land use management is one of the best ways to prevent contamination of groundwater.So in this study, the qualitative protection zone of tow drinking water wells located in the Alluvial area and plain of golestan province, using WHEAM2000 software and use the method of equations in groundwater flow in uniform flow conditions and constant radius, To compare the performance of two methods to calculate protection zone in these areas, was calculated. The results showed that in the presence of hydrological-reliable parameters for the establishment of wells area, the above software can be used as a useful tool for the determining protection zone of wells. Since in the plain area the hydraulic gradient (i) and hydraulic conductivity (k) is lower, so the protection zone calculated by method of equations in groundwater flow in uniform flow conditions and constant radius overlap more than the Alluvial area.

Simulation of Aquifer behavior has great importance in order to identifying the measurement of operation and planning for sustainable usage of these resources. That is why groundwater models predicts qualitative and quantitative aquifer behavior by hydrological, hydraulically and hydrogeological parameters. Since appropriate identification of these parameters increases aquifer simulating accuracy therefore estimating reasonable values of model parameters is crucial real situations planning. In this study one model is provided according to advanced optimization methods for calibrating aquifer hydrodynamics parameters (Sy and k) in Birjand plains. The recommended model is a combination of simulating and optimizing model (Cuckoo Optimization Algorithm) in MATLAB. Calibration period was one year (water year 2010-2011) with monthly13 Stress period. In order to evaluating the value of optimized parameter (calibration period) Validation period was one year period (water year 2011-2012) with 13 monthly Stress period. The accuracy of calibration and validation of model was evaluated by Mean Absolute Error (MAE), Root Mean Square Error (RMSE) and Mean Error (ME) criteria. The amounts of these criteria were respectively 0.48, 0.73 and 0.17 in calibration period and these were respectively 0.63, 0.89 and 0.32 in validation period. Results revealed that presented approach has high accuracy for reasonable estimation aquifer parameters.

Entering turbidity current through reservoir dams and its sediment deposits by the dam body, it not only reduce dam's efficient life but also reduce effective reservoir volume, block intake structures (gates) and damage power-plants. One of the procedures for controlling turbidity current and its erosion through reservoir dams is to create barriers. So in this research, it is evaluated the impact of applying plate barriers and zigzag columnar barriers with tilt angles of 45, 60, 90 degrees against the dam body by using ANSYS-CFX software. the obtained results from a simulation indicates that in subcritical turbidity current, columnar barriers (with relative height of 0.52 equal to the flow depth and with zigzag arrangement) can cause a 60% decrease in discharge flow of turbidity current, and a 5 -fold increase in the density of the barricades, the discharge rate of the turbidity current is decreased by 6%. Furthermore, applying plate barriers with relative height of 1.26 equal to flow height and with deviation angles (tilt angles) of 45, 60, 90 degree to the floor can take under control 50 to 80 percent of the turbidity current. In some cases which it isn' t possible to use the plate barriers because the high altitude is required, it can be applied the column barriers with zigzag arrangement and low height. As well as if barriers are installed in perpendicular position (90 degree) to the turbidity current direction, it will be more efficient than installing barriers with the above-mentioned length in tilt position.

Todays, with population increases and technology advances, excessive use of fossil fuels has increased greenhouse gases in the atmosphere. Increased concentrations of these gases in the atmosphere, lead to an increase in average temperature and consequently the climate change. Also, the climate change can affect the rainfall and runoff. With attention to limited water resources in Iran, the study of this impact is very important for water resources management. In this study, the effects of climate change on Gorganroud river runoff to the Boustan and Golestan reservoirs located in Golestan province of Iran is studied. The minimum temperatures, maximum temperature, hours of sunshine and precipitation are downscaled with LARS-WG model for the period of 2015 to 2040 and under different emission scenarios. The results show about 20 – 25% decrease in rainfall and an increase of about 1 - 2 centigrade degrees in annual temperature. To investigate the effect of these changes on the river runoff, Artificial Neural Network is used to model the relation between rainfall and runoff.And the amount of runoff between years 2015 to 2040 is predicted. The results show a reduction in runoff about 18% in inflo to the Boustan reservoir and 24% in inflo to the Golestan resrevoir catchment in next years. These results represents that the basin needs adapataion and mitigation policies for effective water resourecs management.

Today, underground dams have very popular application for water storage. These dams due to special circumstances which require the choice of the construction site, surface dams are far less than the amount that will be important for the operational management of the dam.aquifer modeling and simulation with finite difference method was used for calibration and verification. The model was used to simulate the desired options.This modeling showed that with regard to the existing conditions at the time the first dam can corpse was in the reservoir and in near dam body dug due to limited network of the even to low as well as refilling possibility from the second year of the same wells and there is low in case the corpse was in distance possible harvesting more.Also the impact of underground gallery in different weird things was examined and it was clear that had no effect on the rate of harvest.The modeling showed that with the first dam and reservoir near the dam can’t be drilled a well that even the low level of the water. But the second year the possibility to withdraw from there as well as low in the case of a well in the distance, there is the possibility of further withdrawals. The effect of underground galleries in different states was investigated and it was found that there is little impact on the harvest rate.

use of unconventional water resources such as saline water has a special importance, especially in arid and semi-arid areas. Increase potential of emitter clogging with saline water can limit the use of saline water in trickle irrigation. In this research, the performance, the emission uniformity, the uniformity coefficient and other hydraulic characteristics of four kinds of pressure compensated emitters used in Iran, with 8 l/h discharge, while using salinity water (EC=12.75 ds/m), were investigated. To his end, the outlet discharge of emitters, after a month of operation, was measured in six consecutive months and analyzed by applying SAS statistical software.Results indicated that the type of emitter is effective on emission uniformity and hydraulic characteristics.According to statistics, time affected the performance of emitters and reduced it. Eu and qvar for the best emitter (micro flapper) were 94% and 19%, respectively.