نشریه مهندسی آب
سال دهم شماره 1 (بهار 1401)

Weirs are hydraulic structures used to control the water level in canals and rivers, and when the water reaches the height of the weirs, they start working and draw water out of the system. This laboratory study analyzes hydraulic changes on four types of congressional series with different lengths (L / P) in free and submerged flow modes. Also, the effect of Calvert placement downstream of the overflow at three distances (d / p = 0.2,0.4,0.6) on the upstream and downstream flow characteristics were investigated, and the results showed that in all four types of the congressional weir, with increasing The hydraulic load ratio increases to about h_0 / P = 0.1 of the flow rate and in this ratio reaches its value and then decreases after this value. Also, the immersion threshold increases with increasing overflow length (L / P). (t / h) ^ * also increases. Relatively longer overflow in the congressional mode than the sharp-edged overflow improves the coefficient of run and, on the other hand, increases the immersion threshold. The results showed that the Calvert at a distance closer to the overflow could affect the characteristics of the flow after the overflow due to the formation of the first wave passing through the overflow (Xw) and increased the flow after the overflow in the submerged state and increased. Immersion threshold and increase immersion ratio (t / h). Moreover,

Tides are affected by complex tidal hydraulic conditions. This study is the effect of constructing an upstream cell dam of Bahmanshir on Karun river from Ahvaz hydrometric station as an upstream border to Hafar three-way as a downstream model boundary. HEC-RAS model has been used to model river conditions in this research. The software output results showed that after the construction of the dam, the trend of changes in the upstream station changed drastically, so that the water level values ​​in Ahvaz, Darkhovin, upstream of the cell dam were measured 4.5, 8, 12 meters, respectively. شد. The average flow velocities in Ahvaz, Darkhovin, upstream and downstream sections of the cell dam are 1.24, 0.87, 1.53, 1.24 m / s, respectively, and the flow velocity after construction and location of thشThis study is the effect of constructing an upstream cell-dam of Bahmanshir on Karoon river from Ahvaz hydrometric station as an upstream border to Hafar three-way as a downstream model boundary. HEC-RAS model has been used to model river conditions in this research. The software output results showed that after the construction of the dam, the trend of changes in the upstream station changed drastically, so that the water level values in Ahvaz, Darkhovin, upstream of the cell dam were measured at 4.5, 8, 12 meters, respectively. The average flow velocities in Ahvaz, Darkhovin, upstream and downstream sections of the cell dam are 1.24, 0.87, 1.53, 1.24 m / s, respectively,

To achieve proper production in agricultural products, it is necessary to find suitable cultivation areas in terms of climate, geography and other parameters involved in growth and production. In this research, the possibility of cultivation and zoning of safflower susceptible areas in Dez basin has been investigated. For this purpose, water, soil, air and physiological information of the plant through library resources and opinions of experts of Khuzestan Agricultural Jihad Organization have been used for the study classification. Then, the effect of each factor on safflower yield was determined using AHP method. In order to locate and zoning the potential points of cultivation in the study area, the ordinary kriging model in GIS software environment was used. The results of data processing showed that 3% of the basin lands are in the appropriate range and 70% are in the medium range suitable for safflower cultivation.

Maroon River is one of the tributaries of Jarahi River and one of the important rivers of Khuzestan province. The importance of quality studies of Maroon River is clear from the fact that this river provides water for cities, villages and thousands of hectares of agricultural lands and industrial factories and finally leads to Shadegan Wetland. Attention and importance to this river is one of the requirements for sustainable development and water quality study of this river is of special importance. Water quality is determined by some physical, chemical and biological characteristics. In this study, the models of the relationship between the two parameters of electrical conductivity (EC) and total soluble solids (TDS) during the years 1346 to 88 fit and the amount of TDS in the future is estimated and finally the validity of this prediction is calculated. The results show that in a sampling period from 1346 to 1388 in Behbahan station, the best fitting model between TDS and EC in this station is the exponential model with a correlation coefficient of 0.913. Having the EC value during the years 1389 to 1392, the amount of TDS in this period was estimated and to select the best model, the amount of EF (model efficiency) was calculated for 4 models and it was found that the exponential model with an efficiency of 99.72% is appropriate. The most common model for estimating the amount of TDS is linear, power and logarithmic models in the next priority ranks in Behbahan station.

Surface runoff and water flow in rivers are always accompanied by soil erosion and sediment transport. Water is one of the most important causes of erosion of the earth's crust and in its path carries materials in solution, suspended and bed load. These materials settle wherever the right conditions require. The presence of these substances in water is very important for drinking, industrial exploitation, agriculture, aquaculture, creating dead volume of dam reservoirs, sedimentation of canals, reducing the capacity of rivers and canals, as well as flood control. These materials are washed from the slopes and plains and cause soil erosion and poor vegetation and environmental degradation.

Trapping efficiency shows the percentage of sediment material entering the reservoir that settles. Trapping efficiency is a function of the ratio of tank volume to annual inlet water volume:- The volume of Shahid Abbaspour Dam reservoir has been estimated at 3 billion cubic meters according to previous studies.- According to the statistics and information of Khuzestan Water and Electricity Organization, the average discharge rate of Karun 3 dam station in the period 1977 to 1999 is equal to 359 cubic meters per second, which the average annual input volume is 11321424000 cubic meters. Therefore, the ratio of reservoir volume to annual inlet water volume is 0.26 , which by extracting the result, trapping coefficients for fine-grained, medium-grained and coarse-grained sediments are 88%, 95% and 98%, respectively, the average total trapping coefficient. 94% sediments have been obtained.

Due to the population growth and their agricultural needs, access to water is considered a serious crisis. The objective of this paper is to simulate groundwater resources in Nobandegan plain, Fars, as a case study, to obtain the path and intensity of groundwater flow, and to determine the distribution and origin of groundwater quality pollutants using GMS software. First, groundwater flow hydraulics in the plain has been simulated, calibrated and validated. Then, having the intensity and direction of groundwater flow in the plain and its interaction with adjacent aquifers, the distribution of qualitative pollutants has been investigated and simulated. Finally, combining groundwater quality and quantity information, possible origin of pollutants in the plain has been investigated and determined. Maximum values for groundwater hardness and salinity in the plain were 1272 (mg / l.CaCO3) and 3178 (µ mho / cm), respectively, which are relatively high and indicate low groundwater quality in the plain. However, pollutant levels decreased in the central areas of the plain where the aquifer thickness increases and some dilution takes place. Groundwater quality is saline in terms of salinity and very hard in terms of hardness. Investigating land use over the plain shows that the possible origins of groundwater pollution are dense agricultural activities in the northern areas, and location of Nobandegan city and villages there. Pollutants concentration in central plain decreased, apparently due to the lack of any city, village, or agricultural activity, in addition to aquifer thickness increase there.