Federico Gómez-Delgado PhD Student Roger Moussa Bruno Rapidel Rintaro Kinoshita Alexis Perez
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Transcript of Federico Gómez-Delgado PhD Student Roger Moussa Bruno Rapidel Rintaro Kinoshita Alexis Perez
Impacts of shade trees on hydrological services and erosionin a coffee AFS of Costa Rica: scaling from plot to watershed
Federico Gómez-DelgadoPhD Student
Roger MoussaBruno RapidelRintaro KinoshitaAlexis PerezPhilippe VaastJean-Michel HarmandOlivier Roupsard
CAFNETProjectINRA
Research questionsWhat is the rate and type of erosion in coffee watersheds and how much do trees reduce it ?
we propose to assess and model the water balance and sediment yield from plot to watershed
Can AF practices be promoted and rewarded as hydrological services?
Hydropower profitability is limited by sedimentation of reservoirs. The tools here developed could help in the negotiation of hydrological services between coffee producers and hydropower institutes/companies in Costa Rica
Study site: Cafnet/CoffeeFlux experiment
Aquiares experimental watershedArea = 1 km2
Mean slope: 20%Max. slope: 89%
Turrialba river watershed
Area = 77 km2
Coffee plantations
Turrialba volcano
COSTA RICACENTRAL AMERICA
Cafnet / CoffeeFluxExperimental display CO2
H2O
Vapor, Carbon, Climate
Flux Tower
• LAI• Interception• Throughfall• Stemflow• Sapflow
Plants + Treesflow experiments
Soil Tubes
Soil water content
Rainfall Stations
Rainfall Streamflow + Turbidity
Hydraulic Flume
Water table level
Piezometers
Experimental Plots
S.Runoff + Erosion
• Infiltrability• Hydraulic conductivity
Soil properties experiments
Rainfall and streamflow
Energy balance, ET flux
Cumulative water balance
Potential and actual ET (AET)
Soil moisture (SM)
Water storage: upper GW box (STZ) middle GW box (SUZ)
Water storage: lower GW box (SLZ)
Observed precipitation (P)
Observed and simul. streamflow (Q)
Simulation of water balance HBV lumped model
very high infiltration => low runoff~> low laminar erosionthen: flooding events non-laminar erosion
Sediment loss by watershed
Surface Runoff (SR) and Sediment Yield (SY)in shaded and non-shaded experimental plots
Experimental Plots
Water balanceEvent 29/06/09, watershed scale
Sediment Yield (SY)Event 29/06/09, plot to watershed scale
Total SY = 564 kg (100%)(measured at theoutlet catchment)
- SY non-shade = 169 kg (30%) - SY shade = 51 kg (9% ) SY road+n.lam.= 344 kg (61%)
Scaled upScaled up
By diff.
2/3 of watershed sediment yield comes from non-laminar sources!
Conclusions
We designed an experimental display in a coffe AF system
(andosols, montaneaous) in order to assess and model:
· the water balance partitioning from plot to watershed
· the sediment yield from plot to watershed
A combination of techiques and models allowed to evidence that:· streamflow was dominated by the base flow (aquifer)
· the infiltration rate was enormous in these conditions (andosols, many roots)
· the laminar erosion was low as compared to the non-laminar erosion
Perspectives
• to close water balance on one full year at least
• to continue accumulating sediment yield
• to assess the influence of tree density and slope on plot erosion and scale up to watershed
• to explain the origin of non-laminar erosion and see how management can reduce it
• to validate in other contrasting watershed (other soil, other slope, other tree density...)
Many thanks!
End of presentation