نشریه مهندسی آب
سال دهم شماره 2 (تابستان 1401)

The paper demonstrates a simulation-optimization framework for enhancing the real-time flood control with gated spillways at places where no flood forecasting data is available. A multi-objective modeling scheme is presented for flood management in a gated spillway in which the operator may specify the priorities on floods based on their different return periods. Two different operation strategies are devised. Both of the operating strategies employ ten-stage policies, which mainly rely on the reservoir water level as the input data. The second strategy benefits from both observed reservoir water level and flood peak. The optimal values of the models parameters are obtained using genetic algorithm. This is a novel approach because none of its policies needs flood forecasting data, thus, making them adaptable to any flood with any return period. To evaluate the performances of the proposed models, the flood control through gated spillway of Karkheh reservoir is considered where flood hydrographs with different return periods are routed through the reservoir.

Water consumption in agriculture, increasing irrigation efficiency, and reducing water consumption against the constant yield of the crop are very important. Therefore, the study of water consumption efficiency in different irrigation methods has a significant role in the macro-agricultural and industrial planning of the country. In the present study, the efficiency of gravity irrigation systems (channelet), low pressure, and pressure irrigation in the lands north of Karkheh Khuzestan (arayez 2&3 project) has been investigated. The results showed that the irrigation efficiency in the pressurized irrigation method was the highest so the total efficiency in the pressurized irrigation system is 64.2% higher than channelet irrigation and 55.8% higher than low-pressure irrigation. Also, irrigation efficiency in low-pressure irrigation methods is about 5.3% higher than in channelet irrigation. Economical studies and analysis of different irrigation systems showed that although the initial cost of setting up a pressurized irrigation system is higher than gravity and low-pressure irrigation, in a long time, it will be economically viable while the return on investment in this project is maximum 5 years.

Bridges are among the most important and most prolific river structures ever used. The three commonly used methods to deal with the scouring phenomenon around the bridges are to place the piers in a lower level than the depth of the erosive pit, to reduce the power of the vortex produced around the base, to use the shrub protection cover, or to use a collar, gaps, or submerged plates around the base bridges. Submerged plates are structures that are installed at the bottom of the river with an angle to the main stream and to prevent river erosion, rivets and base structures of the water and waterway reformation and morphology of the bed, which produces a secondary vortex and Changing the flow pattern in the river bed and, consequently, changing sediment transport and erosion. In this research, the effect of square cross-sectional diameter and the effect of submerged panels on scouring are investigated using SSIIM software.

Drought is one of the most important climatic phenomena that is caused by climatic anomalies. Which occurs periodically due to lack of moisture due to reduced rainfall. Drought duration may vary from month to several years. Therefore, by monitoring and evaluating the drought, the damage caused by it can be reduced. Drought is one of the most important and destructive phenomena that in recent years has left many economic and social effects in the city of Islamabad, West. Therefore, in this study, the drought situation of Islamabad West using rainfall data in 30 years (1991 to 2020) using DIP software on an annual basis of drought status based on PNI, SPI, ZSI, CZI was used as a measure to monitor meteorological drought. The results showed that these indicators were consistent with each other, so that based on the above indicators, the results show that in Islamabad West in 1999 and 2014, the most severe drought occurred in the statistical period. In 2005 and 2008, drought occurred with a moderate drought situation.

In order to investigate the effect of drought stress on yield and yield components of four bread wheat cultivars, an experiment was conducted in the form of split plots based on randomized complete blocks in three replications at Sanandaj Grizzah Agricultural Research Station. In this experiment, irrigation cessation as the main treatment at four levels, including cessation of irrigation in the spike stage, cessation of irrigation in the flowering stage, cessation of irrigation in the milking stage and normal irrigation, and bread wheat cultivars as a sub-treatment in four levels, including Sions were Gascogen, Zarrin and Alvand. The results of this study showed that irrigation cut-off treatment led to a significant reduction in traits such as spike length, 1000-seed weight and grain yield, but traits such as number of seeds per spike, number of spikelets per spike and number of seeds per spike were not significant. The results also showed that Alvand and Zarrin cultivars were the most resistant cultivars to different levels of stress, respectively. In addition, normal irrigation had the best results in increasing the yield and yield components of bread wheat cultivars.

In the present study, the drought of Siminehroud basin was investigated by intelligent Support Vector Machine (SVM) models, Artificial Neural Network (ANN) and Wavelet theory (W). Data from six rain gauge stations in the region were used and drought index was calculated in four time scales. The first-order autocorrelation was also selected as the optimal delay. Then the appropriate structure of the Artificial Neural Network was determined using Trial and Error Method and the three coefficients of the SVM model were determined and modeled. The results of evaluating individual models showed that there is no significant difference between two methods in predicting droughts. Then WANN and WSVM hybrid models were prepared. The results showed that the application of Wavelet theory greatly improved the performance of individual models and the amount of RMSE and MAE indices decreased by 19% and 21% and the correlation coefficient increased by 30%, respectively.