Plants versus streams: Their groundwater-mediated competition at “El Morro,” a developing catchment in the dry plains of Argentina

JOBBÁGY, ESTEBAN G.; LORENZO, SANTIAGO; BUONO, NICOLÁS; PÁEZ, RICARDO; DIAZ, YÉSICA; MARCHESINI, VICTORIA; NOSETTO, MARCELO D.

HYDROLOGICAL PROCESSES

JOHN WILEY & SONS LTD

Año: 2021 vol. 35

0885-6087

Our understanding of how groundwater mediates evapotranspiration/streamflow partitioning is still fragmented and catchment studies under changing vegetation conditions can provide a useful frame for integration. We explored this partition in a flat sedimentary dry catchment in central Argentina in which the replacement of native vegetation with rainfed crops was accompanied by the abrupt formation of groundwater-fed streams by subsurface erosion (i.e., sapping) episodes. Historical records indicated widespread water table rises (~0.3 m y−1 on average). Groundwater level and stream baseflow fluctuated seasonally with minima in the warm rainy season, indicating that evaporative discharge rather than rainfall shapes saturated flows. Diurnal groundwater level fluctuations showed that plant uptake was widespread where water tables are shallow (