Papers, Com. by Barrat Jean - marie
Recharge assessment and related spatial distribution remain a recurrent problem while addressing ... more Recharge assessment and related spatial distribution remain a recurrent problem while addressing groundwater flow modeling development. Hence the study objective was to develop an automated method for computing the groundwater recharge at the mesh scale and for each time step of the aquifer model. The process was applied to the “Iullemeden & Taoudeni Tanezrouft Aquifer Systems” case study spread over 2.5 M km², in Sub-Saharian and Sahel Region where isohyets are ranging from 50 to 1 300 mm yr with large inter-annual variations. The developed process for computerizing the recharge is based on i) literature and existing local studies review, ii) senior experts experience, and iii) land (for dry and wet periods) and morphological parameters obtained by satellite imagery processing and on the rainfall spatio-temporal distribution. Monthly rainfall data are issues from the 1960-2010 recorded measurements in meteorological stations equally spread over the studied area. Land-use was assessed from MODIS satellite images at wet (September) and dry (April) seasons. The SRTM Digital Elevation Model (90m) was used to define geomorphological classes (plateaux, slopes, valleys, drainage system). The developed recharge model is an automation of various developed applications and data processing using ArcGis™ Geographical Information System. Computerised recharge data at mesh level and for each time step are stored in a file at the format required by the groundwater flow model (Visual Modflow™). Recharge maps are also displayed at any time step. This fully automatized iterative process for computing the recharge greatly contributes to a far better assessment of the recharge and makes the recharge much more coherent and reliable than in classical cases of groundwater modelling where recharge is manually assessed by a trial and errors iterative process. Hence, groundwater flow model accuracy is greatly enhanced. This developed process is applicable under any geological and climatic conditions notwithstanding some adjustments to the parameters in accordance to the local climatic and geomorphological conditions.
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Papers, Com. by Barrat Jean - marie