Study of mixed water between ground and river

Study of mixed water between ground and river Riparian woodlands depend on local hydrological resources and have to adapt to rapid changes in water levels and soil moisture conditions. This leads us to use stable oxygen isotope (180) and conductivity to trace the distribution and the origin of water. The two main water sources are the river water, coming from upstream rainfall, and the ground water, generally reflecting the mean local rainfall, which can be mixed in the river channel gravel bar. In case of rivers confluence, this model is more complicated due to the presence of a third source of water. Several cases will be presented, from a study realised in the South-West of France downstream of Toulouse and at the confluence of the Garonne and the Ariege rivers.