Titre

Simulated impacts of climate change and land‐clearing on runoff from a small Sahelian catchment

Année de publication

2004

Source

Hydrological Processes 18 3401 3413 17

ISSN
0885-6087
Résumé

In the Sahel, there are few long‐term data series available to estimate the climatic and anthropogenic impacts on runoff in small catchments. Since 1950, land clearing has enhanced runoff. The question is whether and by how much this anthropogenic effect offsets the current drought. To answer this question, a physically based distributed hydrological model was used to simulate runoff in a small Sahelian catchment in Niger, from the 1950–1998 rain‐series. The simulation was carried out for three soil surface states of the catchment (1950, 1975 and 1992). The catchment is characterized by an increase in cultivated land, with associated fallow, from 6% in 1950 to 56% in 1992, together with an increase in the extent of eroded land (from 7 to 16%), at the expense of the savanna. Effects of climate and land use are first analysed separately: irrespective of the land cover state, the simulated mean annual runoff decreases by about 40% from the wet period (1950–1969) to the dry period (1970–1998); calculated on the 1950–1998 rainfall‐series, the changes that occurred in land cover between 1950 and 1992 multiplies the mean annual runoff by a factor close to three. The analysis of a joint climatic and anthropogenic change shows that the transition from a wet period under a ‘natural’ land cover (1950) to a dry period under a cultivated land cover (1992) results in an increase in runoff of the order of 30 to 70%. At the scale of a small Sahelian catchment, the anthropogenic impact on runoff is probably more important than that of drought. This figure for relative increase in runoff contributions to ponds, preferential sites of seepage to groundwater, is less than that currently estimated for aquifer recharge, which has been causing a significant continuous water table rise over the same period. Copyright © 2004 John Wiley & Sons, Ltd.

Type de publication
  • journal
Type de document
  • article
Classification
 
Classification - Inist-CNRS
  • 1 - sciences appliquees, technologies et medecines
  • 2 - sciences biologiques et medicales
  • 3 - sciences biologiques fondamentales et appliquees. psychologie
Classification - Scopus
  • 1 - Physical Sciences
  • 2 - Environmental Science
  • 3 - Water Science and Technology
Classification - Science Metrix
  • 1 - applied sciences
  • 2 - engineering
  • 3 - environmental engineering
Classification - Clarivate Analytics (Subject Category)
  • 1 - science
  • 2 - water resources
Termes extraits

catchment; hydrological; sahelian; runoff; climatic; hydrology; wankama; recharge; copyright; annual runoff; john wiley sons; cappelaere; hydrol; valentin; favreau; savanna; sahel; leduc; groundwater; annual rainfall; anthropogenic; lebel; wankama catchment; niamey; sahelian runoff; casenave; environmental changes; rainfall; gui; iahs publication; hydrological sciences; iahs; aquifer; international association; peugeot; water table; anthropogenic effects; zone width; aquifer recharge; surface runoff; hydraulic; simulation; water resources; climate change; burkina faso; small sahelian catchment; hydrological model; hydraulic conductivity; continental terminal; wallingford; niger; natural vegetation; soil surface states; comptes rendus; climate variability; surface feature; zone widths; sahel region; drainage network; climatic changes; land surface conditions; surface feature maps; runoff production; lower part; niamey area; roughness parameter; whole catchment; rainfall simulation experiments; changements climatiques; raster grid; capillary pressure head; initial soil moisture; hydraulic parameters; uncalibrated model; model calibration; spatial distributions; niamey airport; parameter sets; soil surface features; study site; pond recharge; hydrological processes; rainfall depth classes; runoff increase; shrub savanna; natural savanna; wankama pond; water table rise; groundwater recharge; climatic variability; hydrologic regime; rainfall events; largest rivers; climatic change; same period; relative increase; small catchments; semiarid regions; hydrologic process simulation; endoreic catchment; west niger; west africa; international journal; hydrological modelling; pond water levels; vieux

Entité nommée
 
Entité nommée - Emplacement géographique
  • Montpellier
  • Niamey
  • Niger
  • Zimbabwe
  • Burkina Faso
  • France
Entité nommée - Organisme
  • Niger, Senegal
  • Sons, Ltd.
  • Niger River
  • Burkina Faso, Mah
  • Niger, Favreau
  • USACE
Entité nommée - Personne
B. Cappelaere; G. Favreau; John Wiley; G. Mil; The; S. Massuel; C. Peugeot; U.M.R. Hydrosciences
ark:/67375/WNG-WNJ6GX8T-1
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