@article{fdi:010052916,
  title = {{S}ediment dynamics during the rainy season in tropical highland catchments of central {M}exico using fallout radionuclides},
  author = {{E}vrard, {O}. and {N}emery, {J}ulien and {G}ratiot, {N}icolas and {D}uvert, {C}l{\'e}ment and {A}yrault, {S}. and {L}ef{\`e}vre, {I}. and {P}oulenard, {J}. and {P}rat, {C}hristian and {B}onte, {P}. and {E}steves, {M}ichel},
  editor = {},
  language = {{ENG}},
  abstract = {{T}ropical regions are affected by intense soil erosion associated with deforestation, overgrazing, and cropping intensification. {T}his land degradation leads to important on-site (e.g., decrease in soil fertility) and off-site (e.g., reservoir siltation and water pollution) impacts. {T}his study determined the mean soil particle and sediment residence times in soils and rivers of three subcatchments (3-12 km(2)) with contrasted land uses (i.e., cropland, forests, and rangelands) draining to a reservoir located in highlands of the transvolcanic {M}exican belt. {C}alculations were based on rainfall amount and river discharges as well as on fallout radionuclide measurements ({B}e-7, {C}s-137, and {P}b-210) conducted on rainfall precipitated samples, soil sampled in the catchments, and suspended sediment collected by automatic samplers in the river during most storms recorded throughout the 2009 rainy season. {C}alculations using a radionuclide two-box balance model showed that the mean residence time of particles in soils ranged between 5000 1500 and 23,300 7000 years. {I}n contrast, sediment residence time in rivers was much shorter, fluctuating between 50 30 and 200 70 days. {T}he shortest mean residence times were measured in a hilly catchment dominated by cropland and rangelands, whereas they were the longest in an undulating catchment dominated by forests and cropland. {C}alculation of the {B}e-7/excess-{P}b-210 in both rainfall and sediment allowed gaining insight on sediment dynamics throughout the rainy season. {T}he first heavy storms of the year exported the bulk of the sediment stock accumulated in the river channel during the previous year. {T}hen, during the rainy season, the two steeper catchments dominated by cropland and rangelands reacted strongly to rainfall. {S}ediment was indeed eroded and exported from both catchments during single heavy storms on several occasions in 2009. {I}n contrast, the agro-forested catchment with gentler slopes exported sediment at a constant and low rate throughout the rainy season. {O}verall, land cover and flood type clearly proved to exert more control on sediment export than slope steepness and rainfall erosivity. {O}ur results show the priority of stabilising old gully systems to prevent their extension by regressive erosion to cropland and to concentrate the implementation of on-site erosion control measures in cropland and rangeland of the most reactive catchments.},
  keywords = {{T}ropical environments ; {E}rosion ; {S}uspended sediment ; {R}esidence time ; {F}allout radionuclides},
  booktitle = {},
  journal = {{G}eomorphology},
  volume = {124},
  numero = {1-2},
  pages = {42--54},
  ISSN = {0169-555{X}},
  year = {2010},
  DOI = {10.1016/j.geomorph.2010.08.007},
  URL = {https://www.documentation.ird.fr/hor/fdi:010052916},
}