2nd International Conference on Civil Engineering: Recent Applications and Future Challenges
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Evaluating the temporal variation of groundwater level of the Nubian sandstone aquifer system under Dakhla Oasis using geostatistical analytical technique
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Volume Title: ICCE2021 Vol. 2
Authors
1Associate Professor, Civil Eng. Dept., Assiut University
2Civil Engineering Department, Faculty of Engineering, Assiut University, Assiut, Egypt
3Groundwater sector, Ministry of Water Resources and Irrigation
Abstract
An important area of Egyptian strategic storage is the Nubian Sandstone Aquifer System (NSAS). Dakhla Oasis is one of the most important depressions that depend on groundwater for anthropogenic, irrigation, and industrial activities. One of the applications and importance of the geostatistical analytical technique, such as kriging methods and Inverse Distance Weighted (IDW), is to estimate the groundwater level potential of an aquifer location. This study aims to map the temporal groundwater levels of the NSAS below Dakhla Oasis by selecting the most appropriate mapping technique. For that, a sensitivity analysis is used for selecting the most appropriate mapping techniques of the ordinary kriging, universal kriging, and IDW techniques by using the Geographic Information System (GIS). Digital Elevation Model (DEM) is used for extracting the topographic surface of Dakhla Oasis. Data on groundwater hydraulic heads are collected from the Ministry of Finance Resources and Irrigation. The results show that the IDW mapping technique produced more accurate interpolation than ordinary and universal kriging techniques with RMSE values of 0.98m and 0.845m for IDW and ordinary kriging. The produced maps of hydraulic heads show that, the hydraulic heads drawdown within the years from 1962 to 2007 is 24m in the middle region of the study area, with an average rate of 0.54m/year. On the other hand, drawdown for the western region was about 12m within years from 1969 to 2007 with an average rate of 0.27m/year. Conclusively, it is recommended to prevent excessive pumping rates in the middle and western regions.
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