Khalid Nayl - Academia.edu (original) (raw)

Papers by Khalid Nayl

Research paper thumbnail of Groundwater Assessment using Numerical Flow Model: A Case Study in Gash Sub-Basin-Kassala State, Sudan

ASM science journal, Apr 12, 2023

The main objective of groundwater modelling in Gash River Sub-basin, is to investigate the effect... more The main objective of groundwater modelling in Gash River Sub-basin, is to investigate the effect of hydrologic, hydrogeological parameters and stresses on hydrodynamic behavio ur through the implementation of a realistic three-dimensional groundwater flow model. Severe decline of water level due to uncontrollable heavy abstraction, exposes a water scarcity problem especially in summer seasons. The model was developed for four geological layers encompassing two aquifer zones. The improved three-dimensional visual MODFLOW Code was selected, implemented and run using WHS method to solve the finite difference equation using trail-and-error calibration procedure at Kassala Area. The transient model was successfully calibrated with acceptable results of model calibration criteria. The contour maps of the simulated heads were performed as potentiometric surface. The general flow direction of the groundwater is from southeast towards northwest part of the area and from Gash River course towards the east and west directions as detected from gradual decreasing of potential line's values in those directions, confirming the aquifer recharge from Gash River. The similarity of potentiometric surface contour maps of the two aquifers confirm the aquifers hydraulic interactions. It is found that t he increasing pumping rate caused considerable increase in drawdown as detected from pumping rate incremental scenarios. Moreover, incremental pumping rate scenarios also reflected increasing river leakage into the aquifer system due to disturbance of water balance due to water level decline. The components of water budgets were calculated and its percentage was performed for the hydrologic balance. The difference between inflow and outflow of the water balance shows a deficit in most stress periods of the model simulations. Calibration fitness was accomplished at most of the observation wells suggesting that the groundwater model is an accurate representation of the actual historic groundwater system and confirm the validity of the model to forecasting purp oses. It was found that the model is more sensitive to hydraulic conductivity and least sensitive to specific yield (Sy). Hence, precaution should be revealed for hydraulic conductivity in forecasting model usage.

Research paper thumbnail of Groundwater Potentialities of the Atbara Valley Khashm Elgirba - Elsasareeb Strip Kassala state, Eastern Sudan

Thesis submitted to the Gr d a uate College in accordance with the Requirements for the Master D ... more Thesis submitted to the Gr d a uate College in accordance with the Requirements for the Master D ' ' egree of Science in Geology.

Research paper thumbnail of Geo-electrical Investigations for Groundwater Exploration in the Area Between Wad El Helew and Khashm El Girba Towns, River Atbara Valley, Eastern Sudan

Geophysical investigation has been carried out to explore the groundwater occurrence in the area ... more Geophysical investigation has been carried out to explore the groundwater occurrence in the area between Wad Elhelew and Khashm El Girba towns, Kassala and Gedaref States, eastern Sudan. Vertical electrical sounding technique was applied using Schlumberger Array (configuration), with a maximum half separation AB/2 = 900 -1000 m. The study area covered by (177) points of vertical electrical sounding (VES) measurements distributed to cover the study area at the both sides of the River Atbara and Setit, (Figure 9). The VES points distributed to fill the gabs where there are no wells and to detect the boundary of the aquifers. Based on variations in apparent resistivity of various formations and sequences the study area was divided into three sectors; upstream area, Middle area and downstream area. Three geo-electrical sections constructed in the study area in E-W direction. From the data interpretation; the Aquifer zones in the study area seems to be wider upstream and gets narrower do...

Research paper thumbnail of Groundwater potentialities assessment of the River Atbara alluvial sediments El Girba-New Halfa area, eastern Sudan

Research paper thumbnail of Groundwater Assessment using Numerical Flow Model: A Case Study in Gash Sub-Basin-Kassala State, Sudan

ASM science journal, Apr 12, 2023

The main objective of groundwater modelling in Gash River Sub-basin, is to investigate the effect... more The main objective of groundwater modelling in Gash River Sub-basin, is to investigate the effect of hydrologic, hydrogeological parameters and stresses on hydrodynamic behavio ur through the implementation of a realistic three-dimensional groundwater flow model. Severe decline of water level due to uncontrollable heavy abstraction, exposes a water scarcity problem especially in summer seasons. The model was developed for four geological layers encompassing two aquifer zones. The improved three-dimensional visual MODFLOW Code was selected, implemented and run using WHS method to solve the finite difference equation using trail-and-error calibration procedure at Kassala Area. The transient model was successfully calibrated with acceptable results of model calibration criteria. The contour maps of the simulated heads were performed as potentiometric surface. The general flow direction of the groundwater is from southeast towards northwest part of the area and from Gash River course towards the east and west directions as detected from gradual decreasing of potential line's values in those directions, confirming the aquifer recharge from Gash River. The similarity of potentiometric surface contour maps of the two aquifers confirm the aquifers hydraulic interactions. It is found that t he increasing pumping rate caused considerable increase in drawdown as detected from pumping rate incremental scenarios. Moreover, incremental pumping rate scenarios also reflected increasing river leakage into the aquifer system due to disturbance of water balance due to water level decline. The components of water budgets were calculated and its percentage was performed for the hydrologic balance. The difference between inflow and outflow of the water balance shows a deficit in most stress periods of the model simulations. Calibration fitness was accomplished at most of the observation wells suggesting that the groundwater model is an accurate representation of the actual historic groundwater system and confirm the validity of the model to forecasting purp oses. It was found that the model is more sensitive to hydraulic conductivity and least sensitive to specific yield (Sy). Hence, precaution should be revealed for hydraulic conductivity in forecasting model usage.

Research paper thumbnail of Groundwater Assessment using Numerical Flow Model: A Case Study in Gash Sub-Basin-Kassala State, Sudan

ASM science journal, Apr 12, 2023

The main objective of groundwater modelling in Gash River Sub-basin, is to investigate the effect... more The main objective of groundwater modelling in Gash River Sub-basin, is to investigate the effect of hydrologic, hydrogeological parameters and stresses on hydrodynamic behavio ur through the implementation of a realistic three-dimensional groundwater flow model. Severe decline of water level due to uncontrollable heavy abstraction, exposes a water scarcity problem especially in summer seasons. The model was developed for four geological layers encompassing two aquifer zones. The improved three-dimensional visual MODFLOW Code was selected, implemented and run using WHS method to solve the finite difference equation using trail-and-error calibration procedure at Kassala Area. The transient model was successfully calibrated with acceptable results of model calibration criteria. The contour maps of the simulated heads were performed as potentiometric surface. The general flow direction of the groundwater is from southeast towards northwest part of the area and from Gash River course towards the east and west directions as detected from gradual decreasing of potential line's values in those directions, confirming the aquifer recharge from Gash River. The similarity of potentiometric surface contour maps of the two aquifers confirm the aquifers hydraulic interactions. It is found that t he increasing pumping rate caused considerable increase in drawdown as detected from pumping rate incremental scenarios. Moreover, incremental pumping rate scenarios also reflected increasing river leakage into the aquifer system due to disturbance of water balance due to water level decline. The components of water budgets were calculated and its percentage was performed for the hydrologic balance. The difference between inflow and outflow of the water balance shows a deficit in most stress periods of the model simulations. Calibration fitness was accomplished at most of the observation wells suggesting that the groundwater model is an accurate representation of the actual historic groundwater system and confirm the validity of the model to forecasting purp oses. It was found that the model is more sensitive to hydraulic conductivity and least sensitive to specific yield (Sy). Hence, precaution should be revealed for hydraulic conductivity in forecasting model usage.

Research paper thumbnail of Groundwater Potentialities of the Atbara Valley Khashm Elgirba - Elsasareeb Strip Kassala state, Eastern Sudan

Thesis submitted to the Gr d a uate College in accordance with the Requirements for the Master D ... more Thesis submitted to the Gr d a uate College in accordance with the Requirements for the Master D ' ' egree of Science in Geology.

Research paper thumbnail of Geo-electrical Investigations for Groundwater Exploration in the Area Between Wad El Helew and Khashm El Girba Towns, River Atbara Valley, Eastern Sudan

Geophysical investigation has been carried out to explore the groundwater occurrence in the area ... more Geophysical investigation has been carried out to explore the groundwater occurrence in the area between Wad Elhelew and Khashm El Girba towns, Kassala and Gedaref States, eastern Sudan. Vertical electrical sounding technique was applied using Schlumberger Array (configuration), with a maximum half separation AB/2 = 900 -1000 m. The study area covered by (177) points of vertical electrical sounding (VES) measurements distributed to cover the study area at the both sides of the River Atbara and Setit, (Figure 9). The VES points distributed to fill the gabs where there are no wells and to detect the boundary of the aquifers. Based on variations in apparent resistivity of various formations and sequences the study area was divided into three sectors; upstream area, Middle area and downstream area. Three geo-electrical sections constructed in the study area in E-W direction. From the data interpretation; the Aquifer zones in the study area seems to be wider upstream and gets narrower do...

Research paper thumbnail of Groundwater potentialities assessment of the River Atbara alluvial sediments El Girba-New Halfa area, eastern Sudan

Research paper thumbnail of Groundwater Assessment using Numerical Flow Model: A Case Study in Gash Sub-Basin-Kassala State, Sudan

ASM science journal, Apr 12, 2023

The main objective of groundwater modelling in Gash River Sub-basin, is to investigate the effect... more The main objective of groundwater modelling in Gash River Sub-basin, is to investigate the effect of hydrologic, hydrogeological parameters and stresses on hydrodynamic behavio ur through the implementation of a realistic three-dimensional groundwater flow model. Severe decline of water level due to uncontrollable heavy abstraction, exposes a water scarcity problem especially in summer seasons. The model was developed for four geological layers encompassing two aquifer zones. The improved three-dimensional visual MODFLOW Code was selected, implemented and run using WHS method to solve the finite difference equation using trail-and-error calibration procedure at Kassala Area. The transient model was successfully calibrated with acceptable results of model calibration criteria. The contour maps of the simulated heads were performed as potentiometric surface. The general flow direction of the groundwater is from southeast towards northwest part of the area and from Gash River course towards the east and west directions as detected from gradual decreasing of potential line's values in those directions, confirming the aquifer recharge from Gash River. The similarity of potentiometric surface contour maps of the two aquifers confirm the aquifers hydraulic interactions. It is found that t he increasing pumping rate caused considerable increase in drawdown as detected from pumping rate incremental scenarios. Moreover, incremental pumping rate scenarios also reflected increasing river leakage into the aquifer system due to disturbance of water balance due to water level decline. The components of water budgets were calculated and its percentage was performed for the hydrologic balance. The difference between inflow and outflow of the water balance shows a deficit in most stress periods of the model simulations. Calibration fitness was accomplished at most of the observation wells suggesting that the groundwater model is an accurate representation of the actual historic groundwater system and confirm the validity of the model to forecasting purp oses. It was found that the model is more sensitive to hydraulic conductivity and least sensitive to specific yield (Sy). Hence, precaution should be revealed for hydraulic conductivity in forecasting model usage.