ABSTRACT
This chapter provides the basics of the development of water courses between the Lot and the Verdon. The ecological impacts of such development depend on its nature and its location on the water course. The hierarchy of ecological factors is modified in summer, during low water. The ecological impact of only the hydroelectric works is known, the navigation embankments having been built before the first fish census. That impact manifests itself differently according to the various levels of the Lot. A development model of phytoplankton of the Lot was constructed to simulate its dynamics as a function of water transit time, luminosity, temperature, and nutrients—nitrates, phosphates, and silica. The impact of regulated flows is different in the middle Verdon, which is subject to a sluice regime and daily leaching of the substrate, and the lower Verdon, where the slow, regular flow allows sedimentation of fine particles.
