Catchment integration
In order to estimate base water yields for different areas we considered that base flows were generated either by the full watershed as defined by its surface topography (i.e. topographically defined catchment) or, alternatively, by a more restricted zone that was defined considering the uniform spacing among the relatively parallel stream lines observed in the region and recognized as the typical fishbone structures of sapping erosion regimes (Grau Galofre & Jellinek, 2017). We observed distinctive regular spacings of 2.6 and 12.5 km in the higher-intermediate and intermediate-lower belts of the catchment (respectively upstream and downstream of the rock basement level drop line, Figure 2A), and used those widths combined with the length of streams crossing each zone to calculate their contributing area (i.e. geometrically defined catchment)