@article{fdi:010074396,
  title = {{I}nteracting land use and soil surface dynamics control groundwater outflow in a montane catchment of the lower {M}ekong basin},
  author = {{R}ibolzi, {O}livier and {L}acombe, {G}. and {P}ierrete, {A}. and {R}obain, {H}enri and {S}ounyafong, {P}. and {D}e {R}ouw, {A}nneke and {S}oulileuth, {B}. and {M}ouche, {E}. and {H}uon, {S}. and {S}ilvera, {N}orbert and {L}atxachak, {K}. {O}. and {S}engtaheuanghoung, {O}. and {V}alentin, {C}hristian},
  editor = {},
  language = {{ENG}},
  abstract = {{G}roundwater contribution to streamflow sustains biodiversity and enhances ecosystem services, especially under monsoon-driven climate where stream baseflow is often the only available water resource during the dry season. {W}e assessed how land use change influences streamflow and its groundwater contribution in a small headwater catchment subject to shifting cultivation in {M}ontane {S}outheast {A}sia. {C}ontinuous time series of rainfall, reference evapotranspiration, groundwater level, stream discharge and electrical conductivity ({EC}) of surface and groundwater were monitored from 2002 to 2007. {W}ith the rainfall-runoff model {GR}4{J}, we investigated temporal changes in the hydrological behaviour of the study catchment to verify consistencies with observed land use change. {A}n {EC}-based hydrograph separation method allowed estimating the groundwater contribution to 104 stormflow events. {M}ean soil surface crusting rates corresponding to each of the nine land uses identified in the catchment were determined using 236 standard 1-m(2) micro-plots. {M}ean plant cover for each land use was assessed in 10 x 10-m(2) plots. {B}edrock topography and soil layers' structure were assessed by electrical resistivity tomography to determine pathways of subsurface storm flows. {O}ur results indicate that an increase in the catchment's areal percentage of fallow from 33% to 71% led to a decrease in the annual runoff coefficient from 43% to 26%. {T}he concurrent reduction of soil crusting rate over the catchment, from 48% to 30%, increased rainwater infiltration. {C}onsecutively, groundwater contribution to storm streamflow increased from 83% to 94%, highlighting the protective role of a dense vegetation cover against flash floods. {T}he overall reduction of the annual basin water yield for inter-storm streamflow from 450 to 185 nun suggests that the potential gain in groundwater recharge was offset by the increased root water uptake for evapotranspiration, as confirmed by the drop in the groundwater level. {T}his analysis illustrates how two different land uses with opposite impacts on soil permeability (i/ extensive soil surface crusting under annual crops resulting in limited runoff infiltration or ii/ fallow regrowth promoting both infiltration and evapotranspiration) both inhibit groundwater recharge. {T}he maintenance of strips of fallow buffers between annual crop plots can slow down runoff and locally promote infiltration and groundwater recharge while limiting evapotranspiration.},
  keywords = {{H}ydrologic connectivity ; {S}torm and inter-storm streamflow ; {H}ydrological modelling ; {T}racer-based hydrograph separation ; {E}lectrical resistivity tomography ({ERT}) ; {LAOS} ; {MEKONG} {BASSIN}},
  booktitle = {},
  journal = {{A}griculture {E}cosystems and {E}nvironment},
  volume = {268},
  numero = {},
  pages = {90--102},
  ISSN = {0167-8809},
  year = {2018},
  DOI = {10.1016/j.agee.2018.09.005},
  URL = {https://www.documentation.ird.fr/hor/fdi:010074396},
}