الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
Lake Qarun is the one of the main lakes in Egypt .The lake water level is affected by several factors. In this thesis, the interaction between the lake water and groundwater considered as one of the main factors affecting the lake water level. Therefore, this interaction was numerically simulated and developed by using MODFLOW-200S.1t is considered a new version of the three dimension finite difference groundwater model developed by USGS (U.S. Geological survey). Challenge of using MODFLOW-NWT with MODFLOW-2005 led to improve the computational efficiency and the convergence of model. Input data of hydro- Metro logical requirements for one year were fed to the model packages. Other data of drains discharges, lake stage, ground levels, and soil texture of the study area were extracted from previous studies. The water table heads were also found, in previous woke done related to the same study area, as a data were produced by using remote sensing and land surveying. The potential evapotranspiration and the lake evaporation were calculated using Kharrufa Method and Bowen ratio energy budget (BREB) method respectively. The average rainfall was calculated by using the Meteorological data for the study area. The recharge of groundwater was internally and assigned stimulated by using the developed recharge (RCH) Package. The Stream Flow Routing (SFR) Package and lake Package (LAK) were used for controlling groundwater interactions with lakes and drains. The surface-ground water interaction is extremely important for several reasons; firstly, to manage the water flow into or out the lakes and upper aquifer. Secondly, to protect the aquatic ecosystem. Thirdly,to alleviate hazardous flow events. Finally, to optimize surface water and ground water resources.Therefore, there is a pressing need for a better understanding of the dynamic interactions between lake water and ground water in this region and the water balance between the lake and the groundwater. Furthermore, it is necessary to understand the effects of the hydrology of the study area. The study area of the EI-Fayum depression has a catchment area of ~ 1600 krrr’. The Lake Qarun is located in the lowest part of the el-Fayum depression and occupies an area of ~230 krrr’. The three dimensional numerical model of the study area was conducted horizontally by 500x500 m grid and vertically by two layers, including one inactive upper layer to simulate the lake. The simulation period of the transient model was from 1st January 2012 to 31st December 2012. The transient model was calibrated manually. The manual calibration progress was evaluated and the difference between the water table heads (in previous studies) and the simulated heads was within an acceptable range of error. In this study, the simulated heads matched the water table heads(in previous studies) with a determination coefficient equal to 0.996. Not only calibration but also verification were done to examine the probable extreme scenarios to ensure the capability of model to make successful predictions to simulate different future circumstances. The successful model calibration demonstrates that the model can simulate past behavior, whereas the verified model can predict the future. In other words, the calibrated and verified model increase the confidence of the model accuracy and its capability for future prediction.The model sensitivity was examined by changing some parameter such as the horizontal hydraulic conductivity, lake bed leakance, specific yield, and specific storage. The analysis of the model results showed that the model is sensitive to the horizontal hydraulic conductivity (Kj) and specific yield while the lake bed leakance and the specific storage is insensitive with the simulated groundwater heads. Results of calibrated model for the study area of EI-Fayoum depression, were presented as gird map as well as contour map to fully describe the water table levels. Several detailed cross-sections were also presented and contributed to more describing the behavior of water table levels. These sections demonstrated the trend of moving ground water direction from high levels of the depression (high topography) to low levels in the Qarun Lake. This means that groundwater inflow to the lake is significantly higher than the lake seepage to groundwater. The residual amount of the water balance equation is 29.65 million rrr’ /year. At the beginning of the simulation period, the lake stage was 43.00 m below sea level while at the end of simulation, the lake stage was 42.87 m below sea level. Therefore, there was an increase in the surface water level annually by 13.17 cm. The thesis also presented a warning map of surface area around the lake that will suffer a danger of flood plain effect.