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Article Dans Une Revue Journal of Hydrometeorology Année : 2019

Evaluation of Groundwater Simulations in Benin from the ALMIP2 Project

Mehnaz Rashid
  • Fonction : Auteur
Rong-You Chien
  • Fonction : Auteur
  • PersonId : 1050170
Pat J.-F. Yeh
  • Fonction : Auteur
Christophe Peugeot
Aaron Boone
Luc Seguis
Yutaro Yabu
  • Fonction : Auteur
Moussa Boukari
  • Fonction : Auteur
Min-Hui Lo
  • Fonction : Auteur
  • PersonId : 1050171

Résumé

A comprehensive estimation of water budget components, particularly groundwater storage (GWS) and fluxes, is crucial. In this study, we evaluate the terrestrial water budget of the Donga basin (Benin, West Africa), as simulated by three land surface models (LSMs) used in the African Monsoon Multidisciplinary Analysis Land Surface Model Intercomparison Project, phase 2 (ALMIP2): CLM4, Catchment LSM (CLSM), and Minimal Advanced Treatments of Surface Interaction and Runoff (MATSIRO). All three models include an unconfined groundwater component and are driven by the same ALMIP2 atmospheric forcing from 2005 to 2008. Results show that all three models simulate substantially shallower water table depth (WTD) with smaller seasonal variations, approximately 1-1.5 m compared to the observed values that range between 4 and 9.6 m, while the seasonal variations of GWS are overestimated by all the models. These seemingly contradictory simulation results can be explained by the overly high specific yield prescribed in all models. All models achieve similar GWS simulations but with different fractions of precipitation partitioning into surface runoff, base flow, and evapotranspiration (ET), suggesting high uncertainty and errors in the terrestrial and groundwater budgets among models. The poor performances of models can be attributed to bias in the hydrological partitioning (base flow vs surface runoff) and sparse subsurface data. This analysis confirms the importance of subsurface hydrological processes in the current generation of LSMs and calls for substantial improvement in both surface water budget (which controls groundwater recharge) and the groundwater system (hydrodynamic parameters, vertical geometry).

Domaines

Hydrologie
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Dates et versions

hal-02165400 , version 1 (05-07-2019)

Identifiants

Citer

Mehnaz Rashid, Rong-You Chien, Agnès Ducharne, Hyungjun J Kim, Pat J.-F. Yeh, et al.. Evaluation of Groundwater Simulations in Benin from the ALMIP2 Project. Journal of Hydrometeorology, 2019, 20 (2), pp.339-354. ⟨10.1175/JHM-D-18-0025.1⟩. ⟨hal-02165400⟩
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