La recherche du pic de tritium thermonucléaire en zone non saturée profonde sous climat semi-aride pour la mesure de la recharge des nappes : première application au Sahel

The location of the bomb tritium signal at 20 and 12 m depth in the unsaturated sand dunes in the semi-arid part of North Senegal leads to a qualitative estimate of the effective infiltration of 22 and 26 mm. yr -1 . These figures correspond respectively to 6.5 and 8% of the total precipitation since 1963. Tritium content distribution in interstitial water is modelled by convolution of the analytical solution of the dispersion equation. Best fitting of the complete 12 m depth tritium peak is obtained with a dispersion coefficent of 0.03 m 2 .yr -1