How are fluvial valleys formed? Why do rivers cut valleys? Which mechanisms control the rate of fluvial incision? These are universal questions in Geomorphology about river erosion, and researchers from the Centro Nacional de Investigación sobre la Evolución Humana (CENIEH) have addressed them through a comprehensive study centering on the upper course of the Ebro River where it runs through the zones of the Tobalina valley, Miranda depression, and Haro sector, which belong to the provinces of Burgos, Álava, and La Rioja.