The commune of Tamou, located in the Department of Say in Niger, occupies the southwestern part of the Liptako crystallophyllian basement domain. In this area, the problem of the drinking water supply of the populatio...The commune of Tamou, located in the Department of Say in Niger, occupies the southwestern part of the Liptako crystallophyllian basement domain. In this area, the problem of the drinking water supply of the populations is acute, because of the low flow rates of the drillings capturing the crystallophyllian formations and the Voltaian sandstones, the failure rates of the drillings are very high there. Therefore, the main objective of this study is to improve the knowledge of the areas potentially favorable for the implantation of drillings likely to give more satisfactory flow rates. The methodological approach, based on the collection of data (Landsat 7 ETM+ satellite imagery, borehole data, geological and topographical maps) and their processing by a combination of remote sensing and GIS tools and a field check, allowed the elaboration of maps of availability, accessibility and exploitability of the groundwater resources in the study area. The maps developed were analyzed with a Spatial Reference Hydrogeological Information System following the technique of aggregation by weighting to generate the map of productive drilling sites. The results show that the area is moderately rich in groundwater (58%) and that only 31% of the potential is exploitable. The groundwater potential map shows that 46% of the study area is suitable for drilling.展开更多
The study area, located in the Liptako basement of Niger, faces a serious problem of drinking water supply in recent decades. This is linked to exponential population growth and reduced rainfall. The purpose of this s...The study area, located in the Liptako basement of Niger, faces a serious problem of drinking water supply in recent decades. This is linked to exponential population growth and reduced rainfall. The purpose of this study is to map fracture networks from Landsat 7 satellite imagery to identify major subterranean flow corridors in the area. The methodological approach based on the collection of data (Landsat 7 images, DEM/SRTM, flow, transmissivity, static level) and the geological and hydrogeological field reconnaissance and the processing of these data with the following software (ArcGis, Envi, Surfer and RStudio) The results of this study yielded that the number of satellite lineaments is 995, the preferred directions of these satellite lineament are: N0°-10° (13%) and N90°-100° (12%). On the hydrographic network, in situ, the most frequent fracture, vein and dike directions are: N90°-100° (12%), N130°-150° (11%), and N50°-60° (10%). The structural domains identified probably correspond to the main corridors and reservoirs of underground flows. The values of the induced permeability are between 0.05 × 10-8 and 3.4 × 10-7 m/s. The permeability induced by satellite lineaments, which is strongly related to high fracturing densities and major water stream is involved in the hydrodynamic functioning of discontinuous aquifers in the study area.展开更多
This study was conducted in the region of Tahoua the northeastern part of the Southern Illulemeden sedimentary basin. In this region the transboundary aquifer system of Continental Intercalaire (CI) and the Continenta...This study was conducted in the region of Tahoua the northeastern part of the Southern Illulemeden sedimentary basin. In this region the transboundary aquifer system of Continental Intercalaire (CI) and the Continental Hamadien (CH) are potentially rich in underground water especially in free and captive aquifers. More, this water is the main source of drinking water for the populations, the animals and for agriculture and extractive industries. However, the population growth, the agricultural development, and the climate change have a real impact on the dynamics of groundwater and the exploitation of these resources. Hence, this study aims at analyzing the behavior of aquifers and assessing the impact of various natural and anthropogenic factors. Especially it matters to analyze the drilling parameters and cuttings, logging data and pumping test of nine new boreholes. The results reveal that the depths equipped with boreholes catching the CI/CH complex vary from 70 to 800 meters from East to West while the average thickness of the reservoir CH is 50 meters and it mainly consists of coarse sandstone. Drilling penetrated more than 100 meters into the CI without reaching the base. The CI tank is composed of several layers of gravel and clay whilst the CI/CH aquifers flow rates range from 0.2 to 22.8 m3/h/m. So this is cause of great variability of the water potential within this aquifer. Lastly, the transmissivity coefficients are more important in the CH than in the CI, and the water flow average rates range respectively from 29 m/year to 7 m/year.展开更多
文摘The commune of Tamou, located in the Department of Say in Niger, occupies the southwestern part of the Liptako crystallophyllian basement domain. In this area, the problem of the drinking water supply of the populations is acute, because of the low flow rates of the drillings capturing the crystallophyllian formations and the Voltaian sandstones, the failure rates of the drillings are very high there. Therefore, the main objective of this study is to improve the knowledge of the areas potentially favorable for the implantation of drillings likely to give more satisfactory flow rates. The methodological approach, based on the collection of data (Landsat 7 ETM+ satellite imagery, borehole data, geological and topographical maps) and their processing by a combination of remote sensing and GIS tools and a field check, allowed the elaboration of maps of availability, accessibility and exploitability of the groundwater resources in the study area. The maps developed were analyzed with a Spatial Reference Hydrogeological Information System following the technique of aggregation by weighting to generate the map of productive drilling sites. The results show that the area is moderately rich in groundwater (58%) and that only 31% of the potential is exploitable. The groundwater potential map shows that 46% of the study area is suitable for drilling.
文摘The study area, located in the Liptako basement of Niger, faces a serious problem of drinking water supply in recent decades. This is linked to exponential population growth and reduced rainfall. The purpose of this study is to map fracture networks from Landsat 7 satellite imagery to identify major subterranean flow corridors in the area. The methodological approach based on the collection of data (Landsat 7 images, DEM/SRTM, flow, transmissivity, static level) and the geological and hydrogeological field reconnaissance and the processing of these data with the following software (ArcGis, Envi, Surfer and RStudio) The results of this study yielded that the number of satellite lineaments is 995, the preferred directions of these satellite lineament are: N0°-10° (13%) and N90°-100° (12%). On the hydrographic network, in situ, the most frequent fracture, vein and dike directions are: N90°-100° (12%), N130°-150° (11%), and N50°-60° (10%). The structural domains identified probably correspond to the main corridors and reservoirs of underground flows. The values of the induced permeability are between 0.05 × 10-8 and 3.4 × 10-7 m/s. The permeability induced by satellite lineaments, which is strongly related to high fracturing densities and major water stream is involved in the hydrodynamic functioning of discontinuous aquifers in the study area.
文摘This study was conducted in the region of Tahoua the northeastern part of the Southern Illulemeden sedimentary basin. In this region the transboundary aquifer system of Continental Intercalaire (CI) and the Continental Hamadien (CH) are potentially rich in underground water especially in free and captive aquifers. More, this water is the main source of drinking water for the populations, the animals and for agriculture and extractive industries. However, the population growth, the agricultural development, and the climate change have a real impact on the dynamics of groundwater and the exploitation of these resources. Hence, this study aims at analyzing the behavior of aquifers and assessing the impact of various natural and anthropogenic factors. Especially it matters to analyze the drilling parameters and cuttings, logging data and pumping test of nine new boreholes. The results reveal that the depths equipped with boreholes catching the CI/CH complex vary from 70 to 800 meters from East to West while the average thickness of the reservoir CH is 50 meters and it mainly consists of coarse sandstone. Drilling penetrated more than 100 meters into the CI without reaching the base. The CI tank is composed of several layers of gravel and clay whilst the CI/CH aquifers flow rates range from 0.2 to 22.8 m3/h/m. So this is cause of great variability of the water potential within this aquifer. Lastly, the transmissivity coefficients are more important in the CH than in the CI, and the water flow average rates range respectively from 29 m/year to 7 m/year.
