Natural tracers and isotope techniques to definer groundwater recharge and salinization in the Bou Areg coastal aquifer (North Morocco).

The geochemical and isotopic (δ2H, δ18O, δ13C, δ15NNO3, δ18ONO3) characterization of the Bou Areg aquifer (North Morocco) based on samples collected during two surveys in November 2009 and June 2010 allowed the identification of runoff from the mountain regions and agricultural return flows as the main sources of aquifer recharge. The high salinization of the aquifer is not only due to the intensive agricultural activities but it is also associated with the natural quality of the catchment. The isotopic signal of dissolved nitrates allowed for the identification of two main sources of nitrogen in the system: (i) fertilizers and (ii) manure and septic effluents. The study, framed within the UNESCO-IHP sub component of the Strategic Partnership for the Mediterranean Large Marine Ecosystem, represents the first isotopic investigation of the area and will serve as a basis for the promotion of robust science based management practices in the region.