Journal of Water Resources Engineering
Year:2011 | Volume:3 | Issue:5-6-7|Papers Count:12

Wavelet analysis was used to preprocess the river flow time series in the present study. Using continuous and discrete wavelet transforms the given signals which were the Ghar-e-Aghaj River flow time series in studying stations have been decomposed into approximation and detail signals. Approximation signal denoted the basic trend of the signal and the detail signal depicts the irregularities like jumps and sharp spikes. Using the fractal analysis the Hurst number of each time series was calculated and through that the time series correlation and persistency of the signals before and after the de-noising can be retrievable. The average power of signals was also achieved through a spectral method. Studying the signals correlation and the average power one can understand that the signals correlation grow significantly after the preprocessing while the average power decrease to half. Thus, it can be claimed that half of the signal’s energy is the irregularities participation in the total power. Preprocessed and non-processed time series have been predicted using a multi-layer Perceptron artificial neural network with a Levenberg Marquardt training algorithm. Results of the predicting model depicted significant enhancement in the preprocessed river flow time series prediction. Results also showed that the discrete wavelet transform is superior to continuous wavelet transform for data preprocessing.

Flood routing is one of the methods for flood forecasting in rivers to control and manage flood in it. Today, new techniques using Evolutionary Artificial Neural Networks (EANN) based on Artificial Intelligence (AI) is used widely in various fields, especially in water engineering. In this research, routed flood in Karun river, reach Ahwaz-Farsiat using Feed Forward (FF), Multi-Layer Perceptron (MLP) and Radial Basis Function (RBF) of artificial neural networks. The linear cross correlation method was used for efficient input variables selection. The Algorithm Genetic method was used for determining optimum number of nodes in hidden layer of EANNs. Results show that can select efficient input variables by using cross correlation method. In addition the output of models compared with actual values shows that selected MLP model rather to Muskingum and MIKE11 have ability, flexibility and greater accuracy in forecasting and flood routing in Karun river.

Flood is ranked the most disastrous natural phenomenon as it causes the highest financial damage and the largest number of casualties on the annual basis the world over. However, as it is the most important water resource in arid, semi-arid and sub-humid climates, it must be treated with respect. As the Ghareh Aghaj River is the backbone of agriculture in the southern half of the Province of Fars, acquiring reliable information on its characteristics during catastrophic events is of utmost importance. The Watershed Modeling System (WMS) is a newly developed powerful tool, which by benefiting from the geographic information system (GIS), the digital elevation model (DEM), and a few other hydrologic and hydraulic models, it can predict vital parameters urgently needed during major flooding. The objectives of this study were to predict, in rare events, i) the peak flow rate, ii) the time of peak flow occurrence, and iii) the runoff volume. Using the 1:25,000 scale topographic maps, the DEM, and the Topaz model, the physiographic features of the sub-basins, rivers and tributaries of the Ghareh Aghaj Basin (GAB) were delineated. Employing the HEC-HMS, unit hydrographs were constructed for all sub-basins using the rainfall-runoff data for 5 major events. It was observed that the generated results contained 11.0, 19.0, and 12.5% error for the peak flow rate, floodwater volume, and the time of peak flow occurrence, respectively. Sensitivity analysis revealed that both the peak flow rate and floodwater volume were more sensitive to the curve number (CN) than the delay time. This was mainly due to the effect of initial soil water content on infiltration rate and runoff generation. Furthermore, it was concluded that the Simakan sub-basin ranked first in the entire GAB in the water supplying potential rating.

Kor as an important large river in Marvdasht zone, has been utilized for agriculture, water supply, storage, industry and other consumption, Certainly hydrologic study is an important issue in these projects. Data deficiency in most of watersheds has forced us to use indirect methods such empirical relations for flood runoff prediction. Preventing over and underestimation in predictions, it is necessary to calibrate equations for the slightly watershed. In this research we are going to calibrate some common empirical equations like Horton and fuller. For this reason regionalization with cluster analysis to determine homogenous regions will be done at first. Statistical probability analysis, another issue to estimate peak flood runoff at different return period, and evaluation of Doroodzan dam effect on the statistical characteristics of river regime, also will be assessed in this research.

In this study, the relationships between deficit irrigation with optimal cropping pattern were studied. This technique has been used widely, especially in regions facing water deficit. Since Fasa City of Fars Province is placed in warm climate and affected by water stress more than other climatic regions of the province, this city was selected as the study area. A nonlinear programming model with aim to maximize net revenue was used subject to the yield response functions to water and other limitations. The results showed that there is the possibility of increasing income of representative farm by applying full irrigation instead of deficit irrigation in the current pattern and reducing cultivation to use the available water. In addition, in drought conditions, depending on the severity of the crisis and water restrictions, how to decide strategy for irrigation and land is different to the way if the level of water supply reduce to more than half of the current available water, the deficit irrigation strategy is the best options for optimal use of land and minimum available water. In this regard, farmer can reduce his gross margin reduction to a minimum by adopting yield reduction for some crops and changes in their cropping pattern in accordance with their marginal revenue of each unit of water consumption.

The analysis of frequency curves of low flows is a method for estimation of droughts hydrologic and this method is one of the most important methods for estimation of low flow in regions without sufficient data. In this research we had selected suitable hydrometric stations for analysis of low flows and then we had calculated series of annual minimum flows for periods of 10 and 30 days and by use of frequency analysis and comparison of different distributions, we realized that log Pearson type ш is the best distribution. Then we had determined physiographic, ecological and other required parameters for selected areas and by use of analysis factor’s method, we realized the most important factors that affects low flows; survey area, annual average precipitation, drainage density and percent of land that have poor vegetation. To determine congenial regions, we used cluster analysis and then by use of regional analysis Homogenous regions and all regions and by use of multivariable regression models, we estimated low flows with different return period in the Homogenous regions. Investigation of the models showed the models for Homogenous regions had more determination coefficient and less standard error than the models for the total region of study.

Understanding the spatio-temporal distribution of precipitation is an important factor for planning and implementation of soil and water conservation, flood control and drought mitigation projects. Precipitation zoning maps and their variability play an important role in land management activities. The objective of the current research was to evaluate the capability of geo-statistical methods for estimating annual precipitation in the province of Fars. Data of 92 gauging stations with a common period of 20 years were collected and different approaches including ordinary kriging (OK), simple kriging (SK), and deterministic methods such as inverse distance weights (IDW), radial basis function (RBF), local polynomial interpolation (LPI) and global polynomial interpolation (GPI) were assessed based on R, MAE and RMSE. The results showed that the ordinary kriging had higher R and lower RMSE and MAE. Therefore, this method was implemented in the preparation of the isotheral map of the province of Fars. The results indicate advantages of the kriging method over those of the deterministic techniques. Moreover, the results revealed that 45.465% of the province has the annual precipitation range of 200-300 m while only 0.09 % of the province has the highest precipitation range of 900-1000 mm.

Now a day, the role of dams in the human life especially in countries like Iran is known as one of the underlying bases of sustainable development. The spillway is one of the important structures of any dams, that enables the bypass of flood flows or flows that exceed the capacity of the dam. Among the different types of the spillways, ogee spillways are mostly used, regarding their high hydraulic efficiency. The most precise method in studying the problems of this structure, is making physical models and modeling real flows. In order to investigate the flow regime on a part of Mollasadra dam ogee spillway, the physical model of the spillway was built to a 1:30 scale in the flume of the hydraulic laboratory of Marvdasht Islamic Azad University. Data was gathered with different discharges. Analyzing the gathered data by means of hydraulic regimes, it was found that the energy dissipater structures are working properly, due to tested discharges. The C coefficient of the ogee spillway was computed to be 2.86. In addition the regime of the flow was modeled up to the discharge of about 1680 m3/s in the prototype, but we did not see any special hydraulic problem.

The role of dams in the human well-being, especially in countries like Iran is known as one of the underlying bases of sustainable developments nowadays. The spillway is one of the important structures of any dam.[that enables the bypass of flood flows or flows that exceed the capacity. [In other words, controlling the height and the volume of the reservoir is another important function of the spillways. Among the different types of the spillways, ogee spillways are mostly used, regarding their high hydraulic efficiency. According to the fact that testing is proposed to be the most precise method in studying the problems of such structures, this has made the researchers and designers to investigate the hidden aspects of the subject by means of making physical models and modeling real flows. In order to investigate the flow regime on a part of Sivand dam ogee spillway, the physical model of the spillway was built to a 1:100 scale] in the flume of the hydraulic laboratory of Marvdasht Islamic Azad University. [Data were in 14 steps with different discharges. Analyzing the collected data, it was found that the Frude number had the maximum values on the chute structure according to the high velocity. And in the sections between the main and the control spillways the least values for the Frude numbers were observed resulted from submergence of the flow]. The C coefficient of the ogee spillway was computed to be 1/796. In addition, the flow was modeled up to a discharge of about 2000 m3/s in the prototype, Regarding the critical cavitation number in a number of the tests, the dam structure is threatened to damage. Hence, construction of air vents at the outlet section of the spillway is strongly recommended.

With population growing throughout the world, it is necessary to optimize water use especially in agriculture land. In order to investigate the determination of water use efficiency of Cotton using micro irrigation system, a field experiment was conducted in Agricultural and Natural Resource Research Institute of Orzoueyeh, Kerman province. The experiment was conducted in split plot design based on Randomized Complete Block Design (RCBD) with three replications. The treatments were comprised of three levels of crop water requirements (i.e. I1: irrigation based on 125 percent water requirement, I2: irrigation based on 100 percent water requirement, and I3: irrigation based on 75 percent water requirement, in main plot and two tape position patterns as sub plot consisted of conventional (r1) and alternative (r2). All treatments were assessed for productivity, water use and its efficiency, and economical issues as well. The results showed that the yield resulted from I1 was 379 and 1204 kg/ha higher than that of I2 and I3, respectively. In addition, the obtained yield due to r1 system was 377 kg/ha greater than the r2 pattern. Also interaction of treatments on crop yield indicates that the I1r1 treatment has the maximum yield. Despite of use water equality in sub plots, the WUE in r1 was 16 percent higher than r2. However, economical assessment exhibited that system cost in the r2 in comparison with the r1 was 11 percent lower.

Filtration systems including hydrocyclone, sand tank and micron filters are mostly used in under pressure draining projects for preventing physical obstructions. In this research we have studied set of disc and screen filter performance (more than one device) and comparison of the in different discharges more over efforts have been made to determine the applicable location of these two filters with respect to the discharge of project. For this purpose by installing disc and screen filters in the farm of water and soil and industries of agricultural jahad management assistance of karaj and by evaluating the decrement of each device in different discharges the performance of installed set of these filter had been evaluated. In this research the hydraulic drop from one side and economical problems from other side and the express of installing and start - up for each filter caused that in installing filter sets introducing one the results showed that. Using screen filters us suitable for net discharges less than 6 litters per second because of fewer expenses. With considering this point that in most of hydro model drop draining projects is about 0.5 to 0.6 litters per second. So we can say that in drop draining projects less than 10 hectares using screen filters are more suitable, and for conditions the 6 litters per second using disc filters are advised because the disc filters have fewer drops in this condition.

In arid climates, water was a limited resource, and green space could be irrigated with wastewater. Knowledge of quality and chemical composition of industrial Effluent water (EW) for safe and lawful reuses are required. The main reason of this research was to evaluate the effects of different percentages of advanced treated wastewater of Fars chemical industrial factory Wastewater Treatment Plant on 6 spices plant in Sandy Clay Loam soil for a period of 3 months. A factorial experiment was carried out using a complete randomized block design with 3 replications. The results showed that the treatments 50% and 100% of all species and treatments of 20% Cyperus alternifolius had die, but other treatments have grown well and all of them were matched with new conditions. The Most increased of sulfate in the soil was about Cortaderia Selloana 20% and Aloe vera 10% and Minimal increase in sulfate concentration was about Vetiveria zizanioides 10%. More increased of chlorine was a about Cortaderia Selloana 20% and the lowest increase was about Simmondsia chinensis 10%. Soil salinity in irrigation with wastewater shows little increase due to various ions enter the soil by the wastewater. Lowest salinity is about Vetiveria Zizanioides 10% showing success in attracting such high salinity.