Hydrogeology and groundwater management in a coastal granitic area with steep slopes in Galicia (Spain)

Abstract Groundwater availability, management and protection are great challenges for the sustainability of groundwater resources in scattered rural areas Atlantic regions Europe where is only option water supply. This report presents a hydrogeological study coastal granitic area Oia northwestern Spain, which has unique geomorphological features with steep slopes favoring erosion weathered granite. The conceptual model includes: (1) regolith layer, present flat summit mountains; (2) slope debris colluvial deposits, intermediate lowest parts hillside; (3) marine terrace; (4) underlying fractured recharge from rainfall infiltration varies spatially due to variations terrain slope, geology land use. mean annual estimated hydrological balance ranges 75 mm steepest zone 135 areas. flows mostly through detrital formations, have largest hydraulic conductivities. discharges seepage areas, springs, along main creeks into sea. been implemented flow model, later used select best pumping scenario. Model results show that future needs domestic tourist supply can be safely provided eight wells maximum rate 700 m 3 /day.