الفهرس | Only 14 pages are availabe for public view |
Abstract The need for groundwater resources has increased in Egypt due to the increase in population with the conditions of limited surface water resources. So that, the government takes a trend for the development projects of land reclamation projects specifically in the Western Desert to increase the agricultural area and decrease the pressure on Nile and Valley Delta regions. One of the most important new development areas is Moghra region. It is considered one of the areas of the one and a half million-feddan project that has recently received wide attention from the government. Moghra region has hundreds of pumping wells for agriculture development. It is a part of Matrouh governorate which is located in the northern part of the southern Mediterranean coast. This study answers how far these pumping wells will attract seawater to the aquifer system of the region. Seawater intrusion contributes effectively to water salinity increase. A regional three-dimensional finite-difference model for groundwater flow and solute transport has been built to simulate the flow and salinity distribution in Moghra aquifer using the transition zone approach. The model has been built taking into consideration the geological and hydrogeological characteristics of the aquifer system in addition to the hydraulic parameters, which are analyzed using pumping tests records by Aquifer test software then it has been calibrated for the steady-state conditions. The groundwater model of GMS software has been used for these aspects using the SEAWAT code. The SEAWAT code is a combination of two different modules. The first module is MODFLOW, which solves groundwater flow, and the second module is MT3DMS, which solves solute transport in groundwater. The SEAWAT code module takes into consideration the densities of the two different waters. The calibration process depended on two different approaches. The first approach described the dividing lines of the transition zone due to the SWI. The second approach was applied to conduct the perfect matching between the calculated and measured records of the aquifer system. Many scenarios have been operated to predict the behavior of the aquifer system under different pumping conditions including the flow and the salinity concentration of the aquifer system. The results show that the flow and salinity concentration of the groundwater aquifer are affected by pumping. The water level and salinity are predicted under different pumping rates, a fivefold increase in the pumping rate results that the salinity increased between 4% and 26.8% according to the well location. Moreover, the drawdown values reached 162 m, which is about 46.3% of the saturated thickness. The critical pumping scenario of 5000 m3 /d resulted in shifting the 10,000 mg/L iso salinity line to 0.97 km southerly. On the other hand, the effect of pumping on the local scale of the development area is illustrated as the development area was classified into four different zones according to salinity. This classification may help the decisionmakers in the development area planning and the crop patterns that may be suitable for agriculture there. |