Environmental factors influencing streamwater composition on sandstone (Vosges Mountains)

Abstract

The influence of sandstone composition, precipitation, vegetation and relief on streamwater composition at base flow was studied in 95 forested catchments located in the sandstone part of the Vosges Mountains (N.E. France). Catchments lie on four main types of sandstone. Information was acquired for each catchment using a geographic information system (GIS) and spatially distributed databases. Sulphate concentration is mainly negatively correlated to the annual rainfall and positively to the relative area covered by conifers in the catchment. Nitrate is positively correlated to altitude. Sodium, Cl and Si concentrations are strongly inter-correlated and negatively related to the annual precipitation and the relative area of the conglomerate layer in the catchment. Calcium, Mg, ANC (Acid Neutralising Capacity) and pH are negatively correlated to precipitation, and positively correlated to the relative area of the sandstone layer containing dolomitic nodules. This study emphasizes the role of annual rainfall amounts in controlling stream chemistry at base flow. © INRA, EDP Sciences, 2006.