@article{PAR00006569,
  title = {{S}tructure and hydrogeological functioning of an insular tropical humid andesitic volcanic watershed : a multi-disciplinary experimental approach},
  author = {{C}harlier, {J}. {B}. and {L}achassagne, {P}. and {L}adouche, {B}. and {C}attan, {P}. and {M}oussa, {R}. and {V}oltz, {M}arc},
  editor = {},
  language = {{ENG}},
  abstract = {{T}he aim of the study is to establish an hydrogeological scheme of the structure and the functioning of andesitic volcanic systems in the insular and humid tropical context. {A} watershed has been instrumented at {F}efe in {G}uadeloupe ({F}rench {W}est {I}ndies) in the {L}esser {A}ntilles to measure rainfall, runoff and piezometric fluctuations between 2003 and 2006. {G}iven the heterogeneity of the volcanic deposits, a multidisciplinary approach has been used: a geological and an hydrogeological survey, an hydrodynamic approach (hydraulic tests and signal processing of hydrological time series), and finally, an hydrogeochemical approach (major elements and some trace elements). {T}wo main superposed aquifer respectively in aerial deposits, and in recent nuees ardentes (glowing ash) and lava flows, as well as the underlying aquiclude (the highly weathered older substratum) were identified. {A}t a local scale, some hydrogeological heterogeneities internal to the aquifers were highlighted and related to a polyphased building-up of the geological formations. {H}ydraulic relationships between the multi-layered aquifers, such as the confinement of the deep aquifer upstream of the basin, were identified. {G}roundwater/stream exchanges were characterised, detailing various contributions of the shallow and the deep aquifers to stream and spring waters; significant river losses were also observed. {A}t a global scale, within such relatively permeable volcanic formations, the aquifer recharge is about 85% of the annual effective rainfall for an average rainfall year. {T}he hydrogeological scheme appears to be coherent with a geological structure of cut-and-fill paleovalleys frequently observed in andesitic areas. {C}onsequently, groundwater drainage axis are mainly localised in recent nuees ardentes deposits, whereas the inversion of relief characteristic of volcanic areas explains the non-superposition of surface water and groundwater divides and both surface water losses and springs. {F}inally, this work shows the highly heterogeneous hydrogeological processes occurring in volcanic formations of andesitic-type. {I}t also shows the relationships between the geological structure and the hydrogeological functioning of such basins, and proposes an affordable methodological approach to investigate such a hydrogeological context in depth.},
  keywords = {{H}ydrogeology ; {A}ndesites ; {G}eology ; {H}ydrogeochemistry ; {S}ignal processing ; {V}olcanic aquifer},
  booktitle = {},
  journal = {{J}ournal of {H}ydrology},
  volume = {398},
  numero = {3-4},
  pages = {155--170},
  ISSN = {0022-1694},
  year = {2011},
  DOI = {10.1016/j.jhydrol.2010.10.006},
  URL = {https://www.documentation.ird.fr/hor/{PAR}00006569},
}