Over the last two decades, repeated dry periods across the country have clearly highlighted the weaknesses in the balance of needs and surface water resources. The latter are increasingly failing due to the large inte...Over the last two decades, repeated dry periods across the country have clearly highlighted the weaknesses in the balance of needs and surface water resources. The latter are increasingly failing due to the large inter-annual rainfall variability and high exposure to evaporation. Because of their high inertial capacity, groundwater is less affected by interannual fluctuations and compensates for the irregularity of surface water availability. However, in addition to being overexploited, groundwater can be exposed to various types of pollution that can alter their quality, sometimes irreparably. The issue of delimiting the protection perimeters around catchments implies a local development policy that is coherent from the point of view of water management and spatial planning. The present work contributes to the delimitation of the perimeters of protection of groundwater catchments of the Berrechid aquifer. Thanks to the “particle tracking” method through the use of models MODPATH and MODFLOW interfaced to GMS 4.0 (Groundwater Modeling System Version 4.0), we delimited the closed protection perimeters, using the numerical MODPATH model, by drawing the 50-day isochrones. Within these perimeters, any bacteriological or chemical action is prohibited. We delimited also the distant protection perimeters (infinite transfer time) that serve as an extension to the closed protection perimeters (transfer time of 50 days). Feeding areas have been introduced to protect groundwater from substances with insufficient degradation and natural retention. The results obtained show that these wells (catchments (P1 to P9) intended for drinking water supply in the Berrechid region) could be contaminated if the part of the aquifer to the south, upstream of these wells, is polluted by persistent chemical substances. The agricultural activities must be controlled and regulated by the State authorities in order to avoid any risk of contamination of the new boreholes by phytosanitary products since Berrechid region is an agricultural zone.展开更多
文摘Over the last two decades, repeated dry periods across the country have clearly highlighted the weaknesses in the balance of needs and surface water resources. The latter are increasingly failing due to the large inter-annual rainfall variability and high exposure to evaporation. Because of their high inertial capacity, groundwater is less affected by interannual fluctuations and compensates for the irregularity of surface water availability. However, in addition to being overexploited, groundwater can be exposed to various types of pollution that can alter their quality, sometimes irreparably. The issue of delimiting the protection perimeters around catchments implies a local development policy that is coherent from the point of view of water management and spatial planning. The present work contributes to the delimitation of the perimeters of protection of groundwater catchments of the Berrechid aquifer. Thanks to the “particle tracking” method through the use of models MODPATH and MODFLOW interfaced to GMS 4.0 (Groundwater Modeling System Version 4.0), we delimited the closed protection perimeters, using the numerical MODPATH model, by drawing the 50-day isochrones. Within these perimeters, any bacteriological or chemical action is prohibited. We delimited also the distant protection perimeters (infinite transfer time) that serve as an extension to the closed protection perimeters (transfer time of 50 days). Feeding areas have been introduced to protect groundwater from substances with insufficient degradation and natural retention. The results obtained show that these wells (catchments (P1 to P9) intended for drinking water supply in the Berrechid region) could be contaminated if the part of the aquifer to the south, upstream of these wells, is polluted by persistent chemical substances. The agricultural activities must be controlled and regulated by the State authorities in order to avoid any risk of contamination of the new boreholes by phytosanitary products since Berrechid region is an agricultural zone.
