# Modelling surface water and energy transfer in karstic mediterranean forests

Brune Raynaud-Schell, Jérôme Demarty, Jordi Etchanchu, Chloé Ollivier, Léna Collet, Jean Kempf, Jean-Marc Limousin, Marloie Olivier, Albert Olioso, Jean-Marc Ourcival, et al.

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To cite this version:

Brune Raynaud-Schell, Jérôme Demarty, Jordi Etchanchu, Chloé Ollivier, Léna Collet, et al. Modelling surface water and energy transfer in karstic mediterranean forests. EGU General Assembly 2024, Apr 2024, Vienna, Austria. 10.5194/egusphere-egu24-10997. hal-04551052

HAL Id: hal-04551052

https://hal.science/hal-04551052v1

Submitted on 18 Feb 2025

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Modelling surface water and energy transfer in karstic
mediterranean forests

**Brune Raynaud-Schell**<fnref n="1" />, Jérôme Demarty<fnref n="1" />, Jordi Etchanchu<fnref n="1" />, Chloé Ollivier<fnref n="1" />, Léna Collet<fnref n="1" />, Jean Kempf<fnref n="2" />, Jean-Marc Limousin<fnref n="2" />, Olivier Marloie<fnref n="3" />, Albert Olioso<fnref n="3" />, Jean-Marc Ourcival<fnref n="2" />, Guillaume Simioni<fnref n="3" />, and Véronique Leonardi<fnref n="1" />

Droughts are a major factor in the vulnerability of Mediterranean ecosystems, particularly forest
ecosystems, which are mainly located in karstic environments. Under the effects of global change,
these environments are exposed to increasingly frequent and intense droughts. Recent
ecophysiological and isotopic studies have shown that tree roots are able to feed deep enough in
the epikarst to support transpiration during periods of water stress. However, the quantification of
stocks and temporal dynamics are not yet fully established. This calls for the development of
models adapted to the complexity of the environment, with the aim of improving our knowledge
of both aquifer recharge and the hydric functioning of forests. The work carried out in this study
goes in this direction. It aims to suggest, implement and test a SVAT-type model of energy and
water exchanges at the soil-vegetation-atmosphere interface, adapted to Mediterranean forest
environments in karstic zones. The modelling objective is dual: i) to jointly simulate the processes
of diffuse infiltration into the soil (i.e. the superficial part of the root zone) and rapid infiltration
into the network of karstic fractures (i.e. the deep part of the root zone); ii) to simulate the
transpiratory and water extraction processes throughout the root zone. To do this, an adaptation
of the SiSPAT model was developed and then deployed for the first time on two sites in the ICOS
network, namely the forest sites of Font-Blanche (Bouches-du-Rhône, P.I. URFM) and Puéchabon
(Hérault, P.I. CEFE). The results highlight the importance to represent both diffuse and preferential
flows in SVAT modelling for karstic areas. It particularly shows that preferential infiltration builds
up deep water reserves throughout the year. It helps to reproduce better observed transpiration
by the plant canopy during periods of water stress. It also significantly affects the different
hydrological components of the surface, e.g. runoff and drainage to the aquifers.

<footnote n="1">¹Hydrosciences Montpellier, Université de Montpellier, CNRS, IRD, IMT, Montpellier, France</footnote>

<footnote n="2">²Centre d'Ecologie Fonctionnelle et Evolutive, Université de Montpellier, Université Paul Valery-Montpellier</footnote>

<footnote>3, CNRS, IRD, Montpellier, France</footnote>

<footnote n="3">³Ecologie des Forêts Méditerranéennes (URFM), INRAE, Avignon, France</footnote>