Déneigement routier par salage et flux de chlorure de sodium dans le lac du Luitel (massif de Belledonne, Alpes du Nord)

Institut de Géographie Alpine, Université J. Fourier, 14 bis, rue Marie Reynouard, 38100 Grenoble

Abstract

The salting of the Chamrousse road (Belledonne massif, northern Alps) produces an average amount of sodium chloride (NaCl) of 100 mg/l in the water of the lake of the Luitel natural reserve. With view to resolving this problem, the sampling of the lake and recording of measurements, coordinated by the National Office of Forest, shows the diffusion process of NaCl; the rate is determined by hydrolimatic an hydrologic conditions of site. Analysis of the amounts of the NaCl and of the conductivity of lake's water shows a series of peak values rising to 145 mg/l, related to different seasons and change in the weather. Variations are also due to hydrological characteristics of both natural and man-made (road) features of the catchment area. These fluctuations show of the one hand, the direct influence of salting in winter and, on the other, the existence of stocks of salt on the mountain slopes and along the road.