@article{fdi:010063629,
  title = {{S}uspended sediment dynamics in a {S}outheast {A}sian mountainous catchment : combining river monitoring and fallout radionuclide tracers},
  author = {{G}ourdin, {E}. and {E}vrard, {O}. and {H}uon, {S}. and {L}efevre, {I}. and {R}ibolzi, {O}livier and {R}eyss, {J}. {L}. and {S}engtaheuanghoung, {O}. and {A}yrault, {S}.},
  editor = {},
  language = {{ENG}},
  abstract = {{S}oil erosion is intense in mountainous tropical regions where heavy storms result in the supply of large quantities of sediment to rivers. {T}he origin and dynamics of suspended sediment were analysed in a catchment located in northern {L}aos during the first erosive flood of the rainy season in {M}ay 2012. {T}he catchment was equipped with 4 successive gauging stations (draining areas ranging 0.2-11.6 km(2)). {F}allout radionuclides ({B}eryllium-7 - {B}e-7, unsupported {P}b-210 - {P}b-210(xs), and {C}esium-137 - {C}s-137) were determined on rainfall, overland flow, stream water, suspended sediment, soil surface and subsurface samples (with n = 3, 19, 75, 75, 65 and 14 respectively). {A}ssumptions underpinning the {B}e-7-labelling method were validated by implementing experiments in the laboratory (i.e., rainwater {B}e-7 sorption to soil particles) and in the field (i.e., {B}e-7:{P}b-210(xs) activity ratio evolution in rainwater and related overland flow during a natural storm event). {R}adionuclide analyses provided a way to quantify variations in sediment dynamics and origin throughout the flood: (1) a proportion of recently eroded sediment (labelled by {B}e-7, and referred to as "fresh sediment") ranging between ca. 8-35% in suspended loads; (2) higher contributions of fresh sediment at the beginning of the flood rising stage; (3) a progressive dilution of fresh sediment by particles remobilised from the riverbed/channel; (4) the dominance of particles originating from the soil surface (ca. 70-80% of total sediment load) in upper parts and a much larger contribution of subsurface material (ca. 64%) at the downstream station. {T}he original contribution of {B}e-7-labelled particles derived from collapsed riverbanks to sediment export was also demonstrated. {T}his pilot study supports the use of fallout {B}e-7 and {P}b-210(xs) in tropical catchments to constrain sediment dynamics. {I}t also puts forward the need to better characterize the sources of sediment in order to avoid possible misinterpretations.},
  keywords = {{S}uspended sediment ; {F}lood ; {B}e-7 ; {U}nsupported {P}b-210 ; {C}s-137 ; {R}iver monitoring ; {LAOS} ; {ZONE} {TROPICALE}},
  booktitle = {},
  journal = {{J}ournal of {H}ydrology},
  volume = {519},
  numero = {{B}},
  pages = {1811--1823},
  ISSN = {0022-1694},
  year = {2014},
  DOI = {10.1016/j.jhydrol.2014.09.056},
  URL = {https://www.documentation.ird.fr/hor/fdi:010063629},
}