مجله آبیاری و زهکشی ایران
سال نهم شماره 3 (امرداد و شهریور 1394)

The climatic conditions of the main problem in increasing agricultural production and water resources are limited. These factors turning more and more to the pressurized irrigation systems. Among these systems, subsurface drip irrigation. The design and proper management of these enterprises to reduce water loss and optimal use of water and soil nutrients, soil moisture distribution around the dropper knowing how to demand. Shape (diameter and depth of wet soil) and the wetting front in the soil on many factors including texture and layers of soil, soil homogeneity, intensity of water, soil moisture content, slope of the land and water volume depends. The study of the distribution of moisture in the loam and silt loam subsurface Emitters taken. The results showed that the moisture in the soil with loam, silty loam texture will appear later. And because of the shallow depth of the pipes in both the garden, the moisture in the soil surface appearance. According to soil texture and appearance of moisture on the soil surface is recommended depth will increase tubes.

Agricultureas one of the maintopics of development hasan important role in economic development. To achieve agricultural development, its transformation and modernization is inevitable. In terms of groundwater level, the most plains of our country are in the critical and dangerous conditions because of unsuitable spatial and temporal distribution of rainfall, incorrect management policies regarding the use of surface runoff and groundwater over exploitation. In this study, the effect of management approaches including modification of crop pattern and upgrading of irrigation efficiency from 37 to 55 percentage in the form of a management model was discussed on the Fariman-Torbat Jam balancing groundwater resources (6355 km2), in the field scale. This management model based on three scenariosin the form of linear programming was coded and implementedin MATLAB software. The results showed that although theactions of each of these management approaches has stopped the declination of groundwater level, however, the lack of the aquifer which is about 215 million cubic meters will not compensate completely. Also the results showed that upgrading of irrigation efficiency and modification of crop pattern will compensate the lack of the aquifer about 200 and 88 million cubic meters, respectively. Simultaneous application of these approaches not only completely will compensate the lack of the aquifer at the end of ten years management period, but also it saves about 45 million cubic meters of water in this plain. Although this model has good result son water resources management, how ever, it is necessary to study of its effect son employment and income of farmers, separately.

Subsurface drainage is required to eliminate drainage problems and to provide year-round cropping conditions in large areas of the Northern Iran,spaddy fields.With regard to the specific characteristics of these fields such as presence of hard layer of clay at shallow depth and high rainfall in the wet seasons, using an appropriate equation is important for the design of subsurface drainage systems.In this research, the applicability of four unsteady- state drainage equations including Glover–Dumm, Van-Shilfgard, Dezeeuw– Hellinga, and Kraijenhoff– Maaslandwas evaluated to determine subsurface drain spacing in paddy fields. Measurement of water table depth was made daily during a canola growing season, from November 2011 to April 2012, in different treatments of subsurface drainage pilotof Sari Agricultural Sciences and Natural Resources University. Performance of each equation was evaluated using the statistics including efficiency (EF), percent error (PE), coefficient of determination (R2), root mean square error (RMSE) and mean deviation (AD).Among different equations, the Dezeeuw– Hellinga was the best equationfor estimating water table depth during the study period.

Rapid soil erosion is an undesirable phenomenon that reduces soil fertility and water resources capacity and causes water pollution. Investigators have suggested variety of models for prediction of runoff and erosion from which EUROSEM is a distributed single event model that can predict erosion risk from a hydrologic wathershed with respect to space and time. Due to spatial and temporal variations of rainfall magnitude and intensity, soil physical characteristics and topography of watershed area, consideration of these required variables can not be ignored. In this study, the impact of slope and unevenness density of a micro-catchment with heavy clay loam soil texture on runoff and erosion was evaluated using EUROSEM. In the first series, the experiments were performed for three unevennesses with three different densities and three replications in the direction of slopes of 5, 10 and 20 percent. In the second series, the experiments were performed with the same densities and slopes, but in the opposite direction of slopes. Totally, seventy seven tests including witnesses were accomplished. The results showed that density of unevennesses were effective to reduce runoff and erosion, especially when they were set up in the opposite direction of slopes, by 54 percent and erosion by 56 percent. The EUROSEM evaluation also showed that the model was able to assess all hydrograph parameters with regression coefficients (R2) more than 97 percent at the level of 95 percent and RMSE less than 4 percent successfully. Modle also is able to predict some of sedigraph parameters such as time to start sediment, time to peak of sediment and mass flow of sediment with regression coefficients (R2) more than 97 percent at the level of 95 percent and RMSE less than 0.289 percent successfully, but time to peak sediment was not successfully predicted, due to low R2 = 25 percent and high RMSE = 7.56.

Aerated lagoons is a kind of the aerobic suspended growth process that can be used to treat domestic and industrial wastewater. Due to its considerable design flexibility, and time high of remained,the aerated lagoon has gained wide application s in both municipal and industrial wastewater treatment plants. this study aims to investigate the performance of aerated lagoons in the wastewater treatment plant in parkandabad 1 in mashhad, includes two aerated lagoons which includes surface aerators have been used for a period of six month from September to February 2013.Quality indexes such as 5BOD, TSS,, COD, Zn, Cu, Cr in plant influent and effluent were determined the average values of TSS, 5BOD, COD, Cr, Cu, Zn, in plant effluent were measured to be 117mg/l,99.5 mg/l,199 mg,0.00136mg/l,0.1 mg/l,0.and 0.1007mg/l respectively by comparison with standard limits recommended by Iranian EPO, wastewater treatment plant is certified for use agricultural purpose.

Required irrigation water in many of the country plain, supplies from groundwater resources. There are some tools for irrigation management, which we have few information about their performance in Iran. In the present study, the performance of some irrigation management tools, in two citrus gardens were evaluated. The gardens are located in Fasa city of Fars province, and the irrigation systems were in the form of trickle irrigation system. In this study, irrigation waters were scheduled using tensiometer, gypsum block, infrared thermometer, soil moisture meter and the national water requirement document. The irrigation water applied by the gardeners was measured as well. Also economical analysis was performed. Results shows that the irrigation scheduling tools reduce the gardener applied irrigation water about 56 and 46% in the two gardens. The garden yields did not affected by the irrigation scheduling treatments. The water productivity increased about 110 and 54%, comparing to the gardener treatment. All the irrigation scheduling tools were suitable in the both gardens. From economical aspects, the national water requirement document was better than the others.

Actual evapotranspiration (ETa) estimation is a main factor for irrigation scheduling, hydrological balance, design and management of irrigation systems and crop yield prediction. Therefore many researchers have been tried to achieve ETa in different spatial and temporal scales. Remote sensing is one of the newest methods that can be used for this purpose. Therefore, In present study, spatial distribution of daily Eta at a part of Mashhad plain was estimated using Landsat 8 satellite images on 9 June, 25 June, 28 August and 13 September 2013. For this purpose, soil adjusted vegetation index (SAVI) was optimized for SEBAL algorithm. The results showed that there was a correlation between normalized difference vegetation index (NDVI) and ETa in study events. Also, standard deviation of SAVI was the least for L=1 (correction factor of soil background effects). Therefore it can be concluded that optimum amount of L for study region is one. Also the trend of ETr was similar to ETa. It can be concluded that plant cover in agriculture lands had no limitation for accessible of water in study region.

Due to existence of drought periods, decreasing the discharge of the aqueducts and springs and also growing usage of water in study area, administrative sections are eager to do pumping from the groundwater aquifer so aquifer operation management can have an important role in preventing the adverse decrease in water table in this aquifer and creating the Irreparable disaster for attaining this necessity simulator-optimizer model of groundwater was offered. Offered model is a combination of aquifer simulating model (MODFLOW2005-NWT) and multi-objective optimizing algorithm (AMALGAM) in MATLAB programming. For determining the aquifer hydrodynamics parameters, this model was validated and calibrated. The objectives of this model were minimizing the three functions of shortage affected by the failure to supply the necessity, decreasing the water table and Modified Shortage Index (MSI). The presented model was run for a year period with 12 monthly Stress period and Optimal Pareto Front was determined. As one of pareto optimum calculated answers, it can be viewed that when water table remains unchanged, 14.4 million cubic meters of demands exhibit shortage and the amount of MSI will be 3.95. In order to specifying the best option of policy discharge, according to economic, social criteria and environmental effects by administrators and relevant policies, the appropriate optimum answer should been defined among the other optimum and selected pareto answers and also among the discharge amounts corresponding chosen answer. By analyzing the results of using the recommended structure, it can be found that the presented approach has good performance in determining the aquifer optimum policy.

The main purpose of irrigation is to achieve an optimum amount of yield with an economical use of water according to the crop water requirement. An improved irrigation scheduling would lead to the reduction of the excess water use, and the enhancement of crop production. In order to develop a proper irrigation scheduling, actual crop water requirement must be determined. Accordingly, it was attempted to determine the water requirement of tuberose (Polianthes tuberose L.) irrigated by a drip irrigation system and grown in a glass greenhouse located in Varamin during 1392. In order to calculate the water requirement of the tuberose, a simple water balance method was applied.. Tensiometers were installed at two soil depths and were used to determine the time of irrigation events. Irrigation was applied at any time when the soil suction reached to 30 centibar. The Water requirement of Polianthes tuberose for a 144 day growing season (Jun. to Oct.) was found to be 350 mm. The average actual evapotranspiration of Polianthes tuberose was 2.5 mm/day. Based on the data collected from a Class A evaporation Pan located inside the greenhouse, the monthly crop coefficients for tuberose were between 0.5- 0.7.

The use of groundwater resource is very significant in regions such as plain of Birjand. Ease of removal from groundwater sources and potential exploitation of the weak area of surface water resources is one of the main reasons for this. As a result, the protection of groundwater in these areas is very important. Integrated urban wastewater project will impact directly on aquifer of plain. Balance conceptual model of aquifer was coded in VISUAL BASIC for assessment impacts of this plan. Three level of development (A, B, C) for this plan was considered until 2020. A, B levels show develop of plan in 60, 100 percent respectively and C level shows no plane. Precipitation was extracted of output of AOGCM models under three scenarios of A1B, B1, and A2. Head simulation results shows that maximum head loss occurs by 6.8 m in B, 5.5m in A and 3.57m in the scenario of C respectively on 2020. Also these results show that head loss in B is higher than A levels. Head loss in B level is longer than 1.3m in A level.

Numerical simulation is a fast and inexpensive approach to studying optimal management practices. Therefore different model to simulation water content distribution in drip irrigation have been developed in which the general equation of water flow in soil (Richards equation) numerically is solved. In this study 2D equation of saturated-unsaturated flow in soil (2D Richard’s equation) was solved using finite volume method and Crank-Nicolson scheme. The soil hydraulic properties were modeled using the van Genuchten-Mualem relationships. The derived equation set was solved using Jacobi iteration method. Model calibration was done using measured water content distribution around thin-walled drip tubing installed at a depth of 6 cm in irrigated sandy loam soil carried out by Skaggs et al.(2004). Also present model result compared with the result of HYDRUS-2D. The results show with considering suitable boundary condition around the drip, present finite volume model predictions of water content distribution are found with good agreement by the HYDRUS-2D model and measured data. Also present model predicts the water content distribution with mean error less than 7 percent. After, with calibrated model, water content distribution during and after irrigation was investigated when the drip tube was installed in oriented soil surface.

Freshwater lakes are considered one of limited water resources that in recent decades are faced with many problems of quality and quantity. Proper management of these resources requires accurate information of component of the water budget. Evaporation as most unknown term of water budget, have a large share of water losses. To have precise information on the spatial and temporal distribution contribute to principles of qualitative and quantitative planning at water resources. Chanimeh’s artificial reservoirs are located in the east part of the country, with an area 141 Km2 was selected as case study. In this research, evaporation rate were estimated by SEBAL model and using meteorological data and satellite images of MODIS. Pan method applied in the region was used as reference method. As a result, the mapping of evaporation by 25*250 m spatial resolution was obtained. In point compare SEBAL model results with pan observed amount, the model correlation coefficient R, 0.74 and the error average percentage, ±14.5 and RMSD is equal to 2.95 mm. The mean latent heat flux and evaporation in average daily rate for the 202th of Julian days of 2012 year from water surface are equal 308 W/m2 and 13 mm per day, respectively.

An experiment was conducted in order to investigate the effect of deficit irrigation method on yield, yield components and water use efficiency of forage maize (KSC 704) an experiment was conducted during 2013 and 2014 growing seasons in mashhad. A factorial experiment based on randomized complete blocks design with four replications was carried out. Treatments included full irrigation treatment, deficit irrigations (regulated deficit irrigation and replacements of 80 and 60% of total water requirement, variable PRD at 100, 80 and 60% of water requirement and fixed PRD at 100, 80 and 60% of water requirement). Deficit irrigation resulted in water use saving at the rates of 14-28 %. Results showed that plant height, ear height and stem diameter decreased by deficit irrigation. The highest fresh forage yield (75095 kg/ha) was produced by full irrigation treatment. There was no significant difference between fresh forage yield of full irrigation treatment and plants which grew at 80% water replacement and variable PRD method (P≤0.01). The highest water use efficiency was 2.27 kg/m3 which belonged to variable PRD by 80% of water requirement.There was no difference between replacing 100 and 80% of water requirement by applying variable PRD. Overall, results showed that application of variable PRD method saved water by 14% compared with full irrigation treatment without significant reduction in yield and yield components of forage maize.

Study in mixing processes for the management of water quality of rivers is important and one of the environmental concerns. The substrates, such as dunes, are effective in control of transport, production of turbulence and flow resistance in rivers, canals and wetlands It is therefore essential that study is done in this subject. The objective of this study is to investigate the transversal mixing coefficient of dunes. For this purpose, measurements carried out on the fifth to the ninth of dunes in a series of ten dune sand of the synthetic twodimensional. The experiments carried out in a laboratory channel with dimensions of length, width and depth, 20, 0.6 and 0.6 respectively. The dunes had a wave-length of one meter, height 0.8 meters, downstream side slopes 28 degrees and width equal to the channel width. The average diameter of sand dunes used was 14 mm. To evaluate the effect of the delicately ratio on lateral mixing coefficients, two different depths were used. The results showed that dune plays an important role in increasing the lateral mixing coefficient so that in this case this rate was 2.36 times the flat bed. Complete mixing length in the channel bed dunes was 11 meters to the amount indicated on the flat bed of a third. This parameter showed a decrease with increasing depth over the dunes. The tests indicate that the self-purification power of the river on the dunes, comparing to a flat bed, with increasing water depth above of the dunes, increases.

Regarding to the increasing population growth and water consumption, there is a highly emphasis on making culture in modification of water consumption pattern via individual community participating. According to this, the Water Regional Company of Khorasan Razavi organized and performed a cultural project entitled agricultural water saving with participation of teachers and students in the schools of Khorasan Razavi province between 2009 to 2013 years. For this purpose by examination the learning cases which provided for design manager, a questionnaire was designed to determine the views and opinions of teachers who participated in the project. The aim of this paper is to investigate the effect of awareness and learning along with this project. The statistical analysis of various subjects in relation to performance of this design including attitude to saving of water consumption, understanding water crisis and the necessity of project performance in the coming years were performed with the Mann-Whitney and Kruskal-Wallis tests. The results show that the project implementation leads to increasing the participant knowledge of water crises and majority of them have suggested the implementation of project in future years. Furthermore, the highest effect of project (more than 91 percent) are occurred in teacher attitude to saving of water consumption and development of culture. It is recommended that the implementation of this project was not restricted only to agricultural water saving but it should be extended to other fields such as industry and environment (even quantity and quality futures of water). In addition, the formation of non-governmental organizations (NGOs) and campaign to save water, is recommended. It can reform the correct pattern of water consumption to a culture and become a public demand.

To supply discharge in some low pressure irrigation systems, a certain head is required and water is pumped to a tank at a constant height. This height is determined based on peak water requirement. Since the constant speed pump is used in this process, water and energy consumption efficiency are acceptable in only a small range of pressure and discharge. So when we need less discharge or less height, the extra discharge has returned from tank to the suction sump and also height has been provided more. It causes energy losses and reduction on system efficiency. The use of variable speed pumps, which are more flexible in operation conditions, energy loss can be largely avoided. Hence, variable speed and constant speed pumps can be combined so as to meet the real water and energy requirement of system. In this study, regarding to development of low pressure irrigation, hydraulic aspects of the proposed method, how to combine pumps, selection of required revolution of variable speed pumps and economic benefits of variable speed pump replacement in operation, is investigated in a practical problem. Results show that combined pumps in dynamic operation condition, had controlled entry power to the system and had reduced energy losses. Also the efficiency of pumping system increase in high discharges and overall efficiency of pumps decrease in low discharges.