Numerical investigation of groundwater balance and artificial recharge in the Kerman-Baghin Aquifer

In the present paper, the behavior of Kerman-Baghin aquifer has been investigated using the MODFLOW program and GMS 10.3 software. The piezometer data during October 2011 are applied for steady state condition of groundwater modeling. Then, the model is calibrated for 66 months for unsteady condition using observational information, and it is validated for 24 months. Finally, the results are compared with the available observed data and show acceptable accuracy in calibration and validation steps. After validating the model, the status of the aquifer is estimated for a period of 5 years. Management scenarios including 10, 20 and 30 percent reduction in groundwater abstraction as well as artificial recharge at eight selected aquifer sites have been investigated. The location of artificial recharge sites is selected based on seven parameters of land slope, distance from waterways, distance from faults, electrical conductivity, hydraulic conductivity, geology of the area and groundwater depth (thickness of unsaturated area). These parameters are combined with the index overlay method by Arc GIS 10.3 software. The results show that by continuing the current situation, the Kerman-Baghin aquifer could face an average annual deficit of more than 52 million cubic meters. It may cause various problems in the near future including abstraction water from groundwater sources and reducing water quality. The results of implementing different scenarios show that, the best scenario can be obtained by 10% reducing water withdrawal with artificial recharge in four zones 1, 2, 10 and 12

Numerical investigation of simultaneous effect of end sills and roughness on flow characteristics in V-shaped stepped spillways

The special configuration of V- shape stepped spillways increases energy dissipation and aeration compared to the smooth spillways due to the creation of many vortices near the steps. In this research, the energy dissipation in different types of stepped spillways with various horizontal face angles has been investigated using numerical modeling. The FLUENT, was used to model the flow over V-shape stepped spillway. The k-ɛ realizable turbulence model was selected to model the turbulent flow. The numerical results were compared with the available experimental data. The results showed a reasonable agreement between two sets of data. Then the effects of horizontal face angle, roughness and the efficiency of the end sill were investigated by numerical modeling. According to the model results, as the horizontal face angle increased, the energy dissipation also increased. Furthermore, the efficiency of end sill on the stepped spillways increased the rate of energy dissipation about 2.8 to 3.99 percent because the end sill acted like a stilling basin. Moreover, the energy dissipation increased slightly about 0.9 to 1.94 percent by increasing the roughness. Also, areas of steps under the negative pressure that could create cavitation were determined to define the minimum negative pressure and its location in all of models. Finally, the simultaneous effect of several parameters was considered to increase the energy dissipation and the minimum negative pressure

Numerical investigation of bed-load changes on sediment flushing cavity

The tanks' useful life will be reduced if their sediments are not discharged with a suitable method. Various hydraulic and mechanical methods can be used in many countries to discharge sediments from reservoirs. Pressure hydraulic sediment flushing is a method of sediment flushing without lowering the water level. In the present study, using the CFD based Flow-3D software, a model has been applied to investigate the pressure hydraulic sediment flushing, and evaluate the effect of blockage phenomenon on sediment flushing efficiency. Results were compared with the available laboratory model. The dimensions of the simulated tank were 2.5 x 1.3 x 1.5 m in length, width and height, respectively, the height of the bed load was 0.4 m, and the diameter of the sediment particles was 0.3 mm according to the laboratory conditions. The average relative error for the sediment flushing cone depth was about 3%. In addition, to investigate the blocking phenomenon, the height of the bed load was considered to be 0.41, 0.45 and 0.5 meters for each simulation. The simulation results showed that when the height of the bed load increases, there is the highest sediment flushing efficiency and more sediment can be removed from the bottom outlet