Explaining the hydrological behaviour of facultative phreatophytes using a multi-variable and multi-objective modelling approach

[EN] Trees in semiarid conditions survive despite water scarcity and shallow soils because they commonly have access to subsoil water resources. Currently, conventional models do not include groundwater transpiration and the results frequently underestimate the actual evapotranspiration and overestimate the net recharge. Therefore, in this work we focus on how a multi-variable calibration with a multi-objective approach may improve model robustness leading to a more realistic closure of the water balance in two models (LEACHM and TETIS) of different conceptualisation taking into account the specific characteristics of a facultative phreatophytic forest. The results suggest that the common single-variable and single-objective calibration is not able to measure all system¿s characteristics. However, the multi-variable and multi-objective calibration proved a good option to reproduce the water dynamics of a facultative phreatophytic forest and confirmed that groundwater transpiration is an important water source for them. Therefore, hydrological models should include this mechanism and both LEACHM and TETIS proved an acceptable tool to be applied in the regions covered by this species.
This work was supported by the Spanish Ministry of Science and Innovation through the research projects: TETISMED (CGL2014-58127-C3-3-R), SILWAMED (CGL2014-58127-C3-2-R) and TETISCHANGE (RTI2018-093717-B-100), and by the project LIFE17 CCA/ES/000063 RESILIENTFORESTS.