مجله پژوهش آب ایران
پیاپی 8 (بهار و تابستان 1390)

For performance optimization of irrigation canals a suitable combination of indicators must be chosen and optimized in an objective function using an optimization method. But the main problem is choosing appropriate indicators and the lack of a standard method to determine their relative values. The main aim of this research is assessing a proposed method to value indicators in their combination in an objective function in optimization process of irrigation canal performance. For demonstration the capability of ICSSDOM and proposed method, the model was applied on E1L4 of Distributarie's canal of Dez irrigation network. In ICSSDOM, SA (Simulated Annealing) technique is used in a combination with a hydrodynamic model (ICSS). In this research, the most appropriate weighting coefficients of indicators were appointed for performance optimization of irrigation canals using a logical approach which is independent of any professional judgment. According to the results while the weighting coefficient of indicator is considered as a direct proportion of difference between ideal and present performance (), the improvement percent is better than the other conditions. The other important aim in this research is assessing performance of irrigation canals according to different periods of operation (6hours, 8hours, 12hours and 24hours). The results showed that the eight-hour period of operation leads to the more performance improvement. In addition to, above mentioned results, a suitable composition of SA parameters was determined.

Surface irrigation is being the most known method of irrigation in the world and Iran.This is because the furrow irrigation produces tail runoff water in which, efficiency is not as much as the other surface methods. Improving the efficiency by block ending increases scalding probability and controlling discharge need modern facilities and specialist. One of the variable to be managed is furrow geometry. At a constant flow, a depth V-shape cross-section makes advance rate faster and amount of infiltration less than wide U-shape cross-section. In order to find this, a 120 meter furrow was mated in a salty loam soil with two different cross-sections in at Agricultural Station of Tehran University located in Karaj. Furrow cross-sections were made with one furrower mounted to a tractor without any change. Data were collected, using two irrigation processes. Results indicated that a narrow end furrow reduces by advance time 5%,constant of the Kostiakov equation coefficient (a) and infiltration by and increases flow depth, soil moisture content and k coefficient and distribution uniformity respective by 10,19 and 4 to 7 percents 36 % in efficiency but flow depth 10 %, water content in bottom 19%, coefficient (k) and distribution uniformity 7-4% are increased. On the contrary, results obtained for wide U-shape were opposite. Lowest volume of runoff (19.6% of inflow) was produce in completed wide and narrow furrows. However, these variables on the second irrigation were less.

Local scouring immediately downstream of stilling basin is unavoidable when a local velocity exceeds incipient motion. This phenomenon causes a difference in the level of basin concrete bed and natural river bed that is turn affects the rate of scouring. In this study hydraulic model of Namrood dam was used the experiments. Results of this study showed that the stable stone size increases with a reduction of tail water, promotion of critical depth and the level of degradation. Having discharge and tail water depth, the developed relationships in this study could be used to estimate the size of stable stone for any level of degradation

surface run off from different levels of a land carry many types of impurities and so it should be purified before any consumption. To separate these materials three processes can be used: sedimentation, filtration and flotation. The objective of this study is comparing the flotation and conventional systems in removed turbidity. This is an experimental - intervention in a pilot scale study that compare the turbidity, alkalinity, temperature, pH and TSS in conventional sedimentation system with those of dissolved air flotation. Method in this study, poly aluminum chloride used as a coagulants and kaolin was used to produce turbidity. The results showed that was turbidity removal efficiency of dissolved air flotation system in turbidities NTU20, NTU50-30 and NTU110-90,were respectively 14.7, 11.1 and 10.9 percent higher than those of the conventional deposition system, determined of the level of (p<0.01). According to these results to remove turbidity by dissolved air flotation system then is more effectively to common sedimentation. System Using this system for turbidity removal in a water treatment plant with a relative turbidity from stormy areas that often receives turbid water, is recommended.

Inflation of population and rising living standards in many countries need to be enhanced the high quality water suitable for different uses such as agricultural, industrial and drinking sections. Groundwater is one of the most important water supply sources which is encountered with many problems such as drawdown, recharge reduction due to low rainfall and different natural and man-made pollutions. Therefore, monitoring of groundwater quality is very important. In the present research, spatial and temporal analysis of monthly groundwater level fluctuations, from 2003 to 2007, through 50 point wells were investigated. World Health Organization standards and Wilcox method were used in order to classify the drinking and agricultural water usages, respectively. In order to analyze the groundwater quality criteria, Geographic Information System version 9.2 was used. The results indicated higher concentrations of salinity during the wet seasons compared to dry seasons. Therefore, with increasing decline of water level, TDS and EC concentrations had a downward trend. Spatial analysis of groundwater quality showed that the groundwater quality of Qazvin plane is desirable and undesirable for drinking and agriculture by respectively10&6 percent. Also 0.4 and 83.6 percent of the groundwater are desirable and moderate for agriculture usages, respectively.

Local scour hole around bridge piers occurs because of flow separation and developing several vortices. Such scour hole may cause failure of the bridge especially during the river floods. In this study, the use of collars to reduce local scour at a bridge pier is presented with respect to time of scour development. This study was conducted using a 180 degree laboratory flume bend with a relative radius of Rc/B=4.67 with Plexiglas sidewalls. Tests were conducted using one pier with 60 mm diameter in the positions of 60 degree under one flow 32 lit/s and depth 12 cm under clear-water conditions. In this study, the time development of the local scour around the pier fitted with and without collar plates and four sizes of collars fitted at four elevations was studied. The soil materials used in the study had a d50 = 2 mm and geometric standard deviation 1.3. The results of the model study indicated that the maximum depth of scour is highly dependent on the experimental duration. It was observed that, as the size of a collar plate increases, the scour decreases. So minimum depth of scour is dependent on the 3D collar and poisoned at -0.1D elevated.

Ground water resources of Yazd – Ardakan plain (as largest watershed basin in Yazd province) are exposed pollution because of existence 99/4 percent of industrial units. at this study was sampled from 36 drinking water wells. The aim of this study is investigate and predict the changes of qualitative indicators of ground water resources in order to simulate the natural aquifer conditions using several relations in the conceptual model. The results showed that the water quality of observed wells for all parameters were permissible except salt. The main challenges of this plain are the drop of water table about 1.2 m and reduction of water resources quality (by 5.2 percent salt per year) Intensity of salt concentration promotion in drought periods (9.5 percent) is higher than the of salt concentration reduction in the wet period (5.2 percent). If the water consumption was like now, the salt concentration will be 1670 mg/l in 1400 century, but if water consumption be 0/8 percent in 1400 century, it is expected that salt concentration will increase to 1950.

In the past, Geomorphologic Instantaneous Unit Hydrograph (GIUH) had been proposed as a tool to generation of flood hydrographs from storm rainfall data. Nowadays, Spatial Unit Hydrograph is used alternatively, with making use of Geographic Information Systems (GIS)., In this study, based on the concept of spatial unit hydrograph model for estimating the basin response is expressed and determined how the spatial size of the basin and hydrodynamic variables such as wave velocity and diffusion coefficient as advection and hydrodynamic processes affect the runoff basin. The parameter, W, was defined to quantify this important comparative. A series of simulations were performed for basins of different sizes and different spatial distributions of their hydrologic parameters. Result showed that if the hydrodynamic dispersion coefficient is null in all the cells, the flow is governed totally by the geomorphologic mechanisms and the value of W is equal to 1. In this case, a pure advection was done without changing the shape and hydrograph downstream spread and runoff hydrograph reflects the form of the time-area curve of the watershed and is characterized by high frequency oscillations. However, when hydrodynamic dispersion decrease, the hydrological response is influenced mainly by the hydrodynamic mechanisms and the value of the parameter W tends to zero. In this case, the hydrograph assumes a smoother form, presenting a well defined rising limb, peak value and falling limb.

One of the most simple and effective flood control solution is detention rock fill dam. Considerably less construction equipments, technology and cost requirement are the advantage at distension rook fill dams. To find the optimum thickness of such dams, series of experiments were carried out in the field Laboratory Shiraz University (Faculty of Water Engineering), using cobbles with average diameters of D50 = 5 cm, D50 = 7.5 cm and D50 = 10 cm. A relationship between rock fill dam thickness, outflow discharge and average diameter of the cobbles were developed.

Wrong irrigation management is one of the farmer's problems in Jabot district. In other to achieve the best irrigation method and improve the efficiency of tomato water requirements under plastic coverage, the design was conducted to measure tomato water requirements at the level of 50, 75 and 100% in a randomized completely block in a (3.2) factorial method, on Jabot farms for two years long(2006, 2007). The executive results showed that the fruit diameter was not considerably influenced by irrigation level, method and level-method interaction (p>05).The results obtained by comparing the mean yields indicated that dropping irrigation had maximum yield at level of 100% plant water needs as compared with minimum that of surface irrigation one at 50% of plant ones. Totally. It was conducted that the best treat is dripping irrigation at level of 100%. The analysis of economic results was performed using a partial budgeting procedure and also investment preference confirmed that dropping irrigation method with the supply 100% of water requirements is preferable than the other irrigation levels and methods

This study was performed to determine the price elasticity of water demand, value of water marginal productivity in corn production, final price of water and comparison with value of water marginal productivity. Data were collected by using of Multi-stage cluster sampling method through interview with farmers and questionnaire in Bardsir city. Results indicated that in center-pivot irrigation method marginal productivity of 1m3 of water and value of marginal product were 0.26kg and 986 Rials and in basin irrigation system, Productivity of 1m3 of water and value of marginal product were 0.2kg and 371 Rials. Price elasticity of water demand in center-pivot and basin method was calculated -1.97 and -1.57 respectively. With regard to the elasticity of water demand, it can be said that water price has effective rule in rate application. Because of conservation of runoff water network system, decrease of irrigation water demand and proper management is necessary.

The complexity of known phenomenon of cavitations in hydraulic structures is due to different experiences in damage observation and varied effective factors influencing on cavitations initiation. The effective parameters on damage in the dam spillway, are flow velocity, system pressure and surface material strength, operation time duration and air content. In classical damage controlling method, capitation index was used. In this research the fuzzy logic was applied to arrange the damage levels, management and prediction of damage intensity, depending on two important factors, velocity and cavitations index. Verified numerical data of two spillway cases, reported real data, classical predicted damage, and predicted result of a prior fuzzy modeling were used in order to develop and verify the new fuzzy model and test it. The developed model estimated cavitations damage level similar to real damage intensity and predicted damaged region close to the real damaged zone.

In recent decades, consumption of nitrogenous fertilizers has increased environmental pollution. Using low ab cost effective sorbents such as zeolite has been more considered in recent years. In this study, the performance of natural and modified Semnan zeolite, using HDTMA-Br, for nitrate removal was evaluated. The results showed that the modified zeolite had a good performance in nitrate adsorption from laboratory solution and from an agricultural wastewater. By increasing the concentration of solution from 10 to 200 mg/lit, the amount of adsorption increases from 0.2 to 1.4(mg/g)as well. Initial kinetic experiments showed that 150 minutes is needed for reaching equilibrium condition. Furthermore, the amount of adsorption in shaking mode is more than stationary mode and with increasing nitrate concentration from 10 to 200 mg/lit, the difference between their adsorption will increase from 0.05 to 0.37 mg/g.the investigating governing isotherm in shaking and stationary mode showed that Langmuir isotherm has a good agreement for describing nitrate adsorption by zeolite. Modified zeolite by removing 56 percent of nitrate from agricultural waste water showed a good performance in nitrate removal.

Necessity to use envelope is one of the more importance requirements in the design of subsurface drainage system. Sodium adsorption ratio (SAR) and salinity of irrigation water (ECi) are affecting parameters on soil particles dispersion.This potentially causes the sedimentation in drain pipes where no envelope applied. In current research, permeameter test were done to determine gradient ratio and exit gradient in order to evaluate the clogging potential and the probability of soil particle movement into drain pipes using three water samples with different amount of sodium adsorption ratio and salinity. Permeameter tests were accomplished on three drainage systems including drainage system without envelope and drainage system with granular and synthetic (PLM) envelopes. Through this experiment, the values of outflow variation, system permeability, gradient ratio and exit gradient were investigated. Results showed that the values of gradient ratio in the system without envelope were between 1.34 and 2.74 which indicates considerable clogging potential in flow entrance location into drain. Nonetheless, soil particles movement into drain pipe was not observed. whereas in systems with envelope, values of these indicators often were less than one. With calculation of hydraulic failure gradient and comparing this gradient with exit gradient value in each gradient value, soil particle resistance against pressure head was studied. Results indicated that the difference between filtration function of systems without and with envelope were negligible whereas hydraulics function difference between them using the first and the second water samples were significant.

The Penman FAO is one of the appropriate methods for the estimation of evapotranspiration at Bajgah experimental station, Shiraz University. Modeling and forecasting of weekly and monthly time series of evapotranspiration with Penman FAO method using seasonal auto-regressive integrated moving average (SARIMA) models as the linear stochastic models for this station were studied. The time series data of weekly and monthly average of evapotranspiration for the period 1366-1386 were separately considered as the input file of SARIMA models. On the basis of the corrected Akaike's information criterion (AIC) and significant coefficients, and models were selected for weekly and monthly time scales, respectively. The auto-correlation function plots of the residuals for these models have indicated that the residuals are uncorrelated. The weekly and monthly values of evapotranspiration from Khordad 1386 to Ordibehsht 1378 as the test data was forecasted using the fitted models. The results have indicated that the square of correlation coefficient between the observed and predicted values for weekly and monthly time scale is 0.92 and 0.99, respectively. The root mean square error for weekly and monthly time scale is respectively, 0.48 and 0.16 mm.

Sediments induced from the erosion of watersheds, in addition to soil loss and decline in soil fertility, causes the reduction of water quality and endangers the effective life of reservoirs due to sedimentation and managements. So, Estimation of sediment yield of streams is very important for water resources projects planning. So, to use of measurement data or empirical equals need to smaller data of stream and flow. However, sediment transport equations do not agree with each other and require detailed data on the flow and sediment characteristics. Aiming to prediction effect of land uses on soil erosion and sediment yield under various conditions of litho logy and vegetation, using Ilwis system. This study was performed in the Tange Gazi Watershed, a 832 square kilometer catchment, located in the Chahar Mahal and Bakhtiari, Iran. So, with three replications sampling for each homogonous unit, overall 200 samples were resulted and also Required data were provided by field study and Digital images processing. Results of current study shown that the most of the irreversible soil losses and sediment yield by USLE model occurred in the pastures and natural shrubs land uses that located on earthen mountain land units of study watershed. In these land uses, the effect of slope and overgrazing cause to increase of sediment yield in the spring season.

This study was conducted to determine the effect of water stress and nitrogen fertilization on sugarcane yield and the optimum irrigation and nitrogen levels. This experiment was conducted as a split plot with a randomized complete block arrangement at the experimental farm of Khuzestan sugarcane research center during in 2007. Irrigation treatments were full irrigation (I1), %85 (I2) and %70 (I3) of I1. N application consist of 150 (N1), 250 (N2) and 350 (N3) kg/ha. The results indicated that effect of stress on cane yield and sugar yield in I3 and I1 are significant and reductions of Cane and sugar yields were 18 and 17 percent respectively. But we did not observe significantly different between parameters in I1 and I2. Water productivity increased when the water use decreased, but this effect in spite of decrease of water using and increase of sugar purity was not significant because water stress had significant effect on sugar yield. Sugarcane responses to N application were more than irrigation treatments. Cane yield and sugar yield reductions were 26% and 20% in N1 comparison with N3. Water productivity was significant with increase of N application and these results showed that water use and N application are the important parameters to manage of sugarcane yield. Water production was decreased under irrigation treatments. The maximum and minimum cane and sugar yield was observed in I1N3 and I3N1, respectively. Highest and lowest Water productivity was observed in I3N3 and I1N1. According to results the I2 treatment was the best level to irrigation of Khuzestan sugarcane fields.

Evaporation process is considered to be one of the main components in hydrological cycle. Therefore, its accurate estimation plays a vital role in studies of irrigation management and river flow forecasting. In order to estimate evaporation from pan, 5 metrological parameters such as temperature, relative humidity, wind speed, vapor pressure deficit, and extraterrestrial radiation were daily collected during 1993-2007 at Shiraz Synoptic Station. In the first step, from 31 different combinations of input parameters, the best subset including relative humidity, vapor pressure deficit, and extraterrestrial radiation were detected by using the Gamma test (GT). Then, by applying M test, 1100 patterns were selected for an established training model and the rest of 3839 patterns were used for verification of the model. Afterward, based on the GT results, the evaporation model was established by applying adaptive neuro-fuzzy inference system (ANFIS). In addition, the results of this method compared with Marciano empirical equation, and calibrated Stephens–Stewart (S-S) equation. The results come from the evaluation of these models in the test period showed that the ANFIS model and S–S equation with determination coefficients of 0.9023 and 0.8604 on the line of (1:1) and RMSE with 1.342 and 1.614 mm day-1, respectively are more accuracy than other models.

River meanders are major features in rivers and investigation of their flow patterns are important part of river engineering. There are a variety of different models for identifying of flow patterns, but insight in the relevant meander processes is still incomplete and the available models to predict flow have high uncertainties. In this paper, Flow patterns and their changes across channel were investigated. The channel under experiment has curve radius of 1.7m in the centerline and 1.3m width. The experiments in this channel were undertaken with discharges of 63, 89, and 104 l/s on a developed topography. Result showed that, there is a specific interaction between the flow and the bed topography so that having a bed topography, flow patterns can be found. The bed topography leaves a strong footprint on transverse unit discharge and transverse velocity and they include a damped oscillation towards downstream, but longitudinal velocity pattern don’t follow them. Also, flow patterns are like together in these 3 discharges and it shows curve radius effects much more than other parameters on flow patterns.

Adequate and continuous statistical data is the base for hydrology and meteorology studies. Annual maximum 24-h rainfall can be used in different aspects of engineering and design of water course. As a flexible tool that may be adapted to many systems, fuzzy regression was employed to develop a new technique for estimating of missed annual maximum 24-h rainfall data. This research carried out to evaluate the performance of fuzzy regression for reconstruction of annual maximum 24-h rainfall data in Chaharmahal & Bakhtiyari province. To assess the above mentioned model RMSE, P%, R2 were used as statistical indices. The result of obtained from fuzzy regression model was compared with other methods such as normal ratio, graphical, simple linear regression and multivariate linear regression. The determination coefficients (R2) between observed and predicted values by fuzzy regression model were obtained 0.67, 0.75, 0.81 and 0.87 for very-humid, semi-humid, Mediterranean and semi-arid climate zones respectively. The results of reconstructed data indicated that fuzzy regression technique has significant preference comparing other usual method in all the four studied climates in the Province.

In this research, the efficiency of Philip, Kostiakov-Lewis, Soil Conservation Service (SCS) and Horton infiltration models in Verticals and non-Vertisols under two different land uses (rangeland and wheat) with the high and low initial water contents were evaluated. Therefore, the soil water infiltration of the selected sites was measured using single ring method. The parameters of the mentioned models were then obtained using least squares optimization technique. To compare the performance of the models, the mean error (ME), root mean square error (RMSE), mean absolute of mean error (MAME) model efficiency, and Wilmot's index were calculated. The results indicated that at the low initial water content of non-verticals with rangeland land use, the Kostiakov-Lewis model had the best accuracy in describing cumulative infiltration. While, the Philip and Kostiakov models had the highest prediction error of infiltration in the studied soils. The results showed that at the high initial water content of both rangeland and wheat soils the Horton and Philip models predicted the cumulative infiltration with the highest and lowest accuracy, respectively. At the high initial moisture condition the Kostiakov-Lewis and Kostiakov models overestimated and the Horton, Philip and SCS models underestimated the cumulative infiltration. What resulted is the Horton model has the best performance to describe infiltration process at the high initial moisture condition in verticals and non-verticals (RMSE= 0.0783). Whilst, at the low initial moisture condition the Kostiakov-Lewis model had the highest performance in non-verticals (RMSE=0.0596).

Irrigation networks receive high amount of sediments annually, which cause operation and maintenance problems. The effects of sediments and debris, and their possible use in agriculture, were studied by field sediments sampling. Since most of the deposited sediments in irrigation networks are trunsferd from upper parts of the basin or the agricultural soils around them, they contain nutrients and could be used to enhance crop production. In this research, quantity and quality of the deposited sediments in Nekouabad and Abshar irrigation networks in Isfahan Province (taking water from Zayandehrud river), were studied from year 2000 and 2002. The chemical analysis of the sediments showed that average values of SP, EC, pH, OC, P, K, HCO3-, Cl-, SO4-2, Ca+2 and Mg+2, and Na+ were 71.4%, 4.31 ds/m, 7.03, 2.1%, 22.65 mg/l, 136.31 mg/l, 7.81 mg/l, 8.75 mg/l, 41.69 mg/l, 42.3 mg/l and 22.1 mg/l respectively. The texture of the sediments was loam or sandy loam. Comparison of average phosphorus concentration in the sediments showed that this element is more abundant in Abshar network than Nekouabad network (29 mg/l vs. 16.3 mg/l). But, there was no significant difference (p<0.05) between organic matter contents of the sediments (average of 2.11% for the two networks). Cadmium and lead content was negligible. It was also found that deposited sediments in canals were mainly debris and agricultural wastes and not much sediment was coming from. ..

Knowledge of the amount of flood occurrence has a significant impact on reducing human and financial damages caused by the flood. When a flood wave moves downstream a river, its characteristics such as the peak, the time to peak and the duration of the hydrograph will be modified by channel irregularities and roughness. In this study, the one dimensional Saint-Venant equations were simulated with Pressman method, an implicit finite difference scheme, by MATLAB software. Then, the sensitivity analysis of flood routing parameters was studied by using data from three catchments. Analytical investigation of the results indicated that the mean of the absolute value of the sensitivity index for the peak discharge and roughness coefficient parameters are more than other input parameters, and they are 59.33 and 29.95 percentage, respectively. Therefore, it can be said that the outputs of dynamic wave model are more sensitive than these parameters.

In the recent years, the importance of the linear landscape structures (hedge, embankment, and belt trees) increased, due to changes in the landscape and the needs for soil and water conservation. The objective of this research is to quantify the hedgerow impact on some of the hydraulic's soil properties and use of this knowledge for a better understanding the effect of hedgerow network on soil water transfer. Bulk density, hydraulic conductivity and soil retentions curves were established for any horizon and in different distance from hedgerow at a 2m depth ditch. Bulk density and hydraulic conductivity increased with soil depth at all distances. Decreased flood risk, peak flow, and erosion are potential consequences of hedgerow presence.

Suitable design of depth and time irrigation in irrigation systems prevents from water wasting or causing stress to plant. Depth and time irrigation are two basic parameters in trickle irrigation system. System evaluation in the time of operation often shows that these parameters don’t coincide with the wanted goal. As, the evaluation and desirable assigning of these parameters by performing field experiment need to spend much time and cost, so using simulation models for the purpose get to be much importance. Assessment and application chem. flow model for increasing water efficiency in trickle irrigation system is the purpose of this research. In this research, the designing parameters assigned for supplying water requirement of olive tree. After applying the mentioned parameters at the time of irrigation, the wetted depth was measured and it was known that the parameters were overestimated and wetted depth was much needed. By getting the full required data and calibrating the model, the desired value assigned and by applying more water, it was found that the wetted depth has reached to its ideal condition. Also, the results showed that the initial soil moisture and suitable cut off time on the flow had the desired effect on desirable wetted depth so, chemflow model provides the possibility of calibration of mentioned parameters after designing and caused to optimum use of water, reducing water loss and plant stress. ..

The paucity of data on temporal variation of sediment yield on storm basis is one of the fundamental problems for water resources projects and watershed management. However, comprehensive study on sedigraph has been rarely considered. The present study has been therefore conducted to analyze sediment graphs in Khamsan Representative Watershed with an area of 4193 ha in Kurdistan Province, Iran. For this purpose, 4 effective storm events occurred during study period were analyzed. Towards this attempt, suspended sediment samples, rainfall and runoff data were collected with respective to intervals of 60, 10 and 30 min. The conceptual analyses of collected data verified the general dependency of sedigraph from hydrograph and hyetograph and from time to peak of hydrograph.