نشریه مهندسی آب
سال ششم شماره 1 (بهار 1397)

For more accurate measurement of the water flow, it has been always attempted to design structures with least errors and highest accuracy. Nowadays, the use of artificial neural networks (ANN) models has been rapidly grew mainly due to the fact that these models are not confined to the physical parameters. Artificial neural networks are based on use of embedded knowledge between input and output variables of a problem, regardless of physical aspects and these networks are able to extract inherent relation of the input and output and they can generalize the obtained relation to other situations and cases. In the present research, the information related to the overflow of Marun Storage Dam was adopted. The input parameters of ANN model are as follows: day, month, water surface elevation, water sharing percent and output parameters overflow discharge of storage dam. The models employed in artificial neural networks include FF, JEN, MLP and RBF. Moreover, the genetic algorithm (GA

Underground water is one of the important sources of exploitation in arid and semi-arid regions. Therefore, in order to preserve the quality of groundwater, it is important to be aware of the local transmittal and temporal distribution of them. The purpose of this study was to investigate the local variations of groundwater quality in Sabili lands using interpolation method. Sabilly area is located in the north of Khuzestan province, north of Dezful city, which is under planting about 9100 hectares. After landing, reference and digitization of the map and data of the Sabilly area including meteorological parameters, groundwater quality in the area as well as soil science, geology and land classification, layers were created in the ArcCatalog layer. To prepare a variety of quality maps of the area, firstly, the wells studied by x and y (latitude and longitude) were created as points with qualitative information in the GIS software. Then, with the help of interpolation techniques (IDW), the quality maps of the region have been extracted. The results of groundwater quality zoning showed that TDS deviations from 160 mg / lit in the north of the area in al-Mahdi township to 1646 mg / lit in the east of the region in Sarbisheh village has changed.The amount of sodium and potassium in the Sarbisheh area is high and around the Gurpsifid is medium and the rest of the plain is low. The sodium absorption ratio (SAR) in the Sarbisheh area is high and around the Gurpsifid is medium and the rest of the plain is low. The results also showed that, in terms of the bicarbonate hazard of the region, is in the proper category for irrigation, Also the studied area was desirable for irrigation because of this place has been rich in calcium and magnesium.

In this research outputs of the general circulation model HadCM3 under the three climatic change scenarios A1, B1 and A1B are downscaled using LARS-WG model in Shahrekord synoptic weather station and the results were evaluated for the base period (1971-1995) and the future periods 2011-2030 and 2046-2065 for weather parameters of temperature and precipitation. The results of prediction of the model in future periods indicate that the maximum and minimum temperatures increase for all months and scenarios in the study area compared to the base period. Accordingly, the maximum increase in maximum and minimum monthly temperatures was 3.62 and 3.55 °C, respectively, which was observed under the A1B scenario during 2046-2065. Although, the results of the model for the precipitation were very fluctuating and no specific order was observed. However, rainfall decreased in the vegetative seasons of the plants, especially in spring and April and May.

In many water supply and energy projects, such as dams, releasing of a certain flow rate and development of a structure for discharging excessive capacity over a specific time is essential. The structures which are responsible for such task are called weir structure. Such weirs possess high complexity and it is so important to analyze their hydraulic parameters, especially with the use of physical and hydraulic models. Broad crested weirs are extensive used in water transfer system as a tool for measuring the intensity of the stream and controlling water level, due to their economic-effectiveness during construction. With regard to the abundant applications of broad crested weirs, applying any modification on dimension of the sections of these weirs will make these tools more effective in terms of economic. In the present research, the optimum discharge coefficient of the flow was computed by performing experimental studies on the various models. Moreover, variation of discharge coefficient, Froude Number, Upper water level and other hydraulic parameters were simulated using a physical model of broad crested weirs fabricated in hydraulic laboratory and by applying variations on height of the weirs and installing roughness on crown surface. Totally, 75 tests were performed and the results showed that increase in weir crown surface roughness, the discharge coefficient decreases up to 10 percent. Also, the discharge rate increases up to 22 percent, with increase of weir height.

Based on the water surface elevation, there is three types of flow control: flow control at the spillway crest, flow control at the shaft and flow control at the top of the shaft tunnel. In the following research, Flow3D software used for numerical modeling and the results were compared with experimental work, and good agreement was observed. Also, discharge - head graph is plotted for morning glory spillway, which shows by increasing the head, control point moves from the crest to the vertical shaft and then to downstream tunnel. In the case of complete submergence, significant changes in the head are observed with a low increase in flow rate. A parametric study has been done on the length of the vertical shaft and elbow radius. the results show the direct effect of these changes on head of the crest morning glory spillway, so that by increasing the length of the shaft, at a specified discharge increase head on crest, also by increasing the radius of the elbow, the head height on the crest reduced after the submergence elbow of morning glory spillway.

Groundwater quality assessment and site monitoring of these waters is very important for nitrate pollution. In this regard, the spatial variations of groundwater nitrate were investigated using interpolation methods and mapping of these changes. Made This cross-sectional descriptive-analytic study was conducted on drinking water sources in villages in Dezful. For this purpose, 20 drinking water wells were used according to the standard method and 80 samples for 4 season were analyzed. The results showed that the circle Kriging method with less error value than inverse distance weighting, spline and nearest neighborhood methods can perform the optimal zoning for the plain. The summer season has the lowest amount of nitrate and winter. Finally, by investigating the zoning map, it was determined that the eastern and central western regions had the highest amount of nitrate and the north of the plain had a desirable nitrate status.