Soil erosion models get more sophisticated



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Soil erosion models get more sophisticated

  • Soil erosion models get more sophisticated

  • Models more physically based and suitable for different kinds of situations.

  • Price: model require large amounts of input data

    • very temporally dense data (like 10 minute rainfall data)
    • difficult to obtain soil data such as the saturated conductivity.
  • If such data are unavailable: sediment yield models producing yearly averages.



BUT: yearly averages models: ignore lot of other detailed information like:

  • BUT: yearly averages models: ignore lot of other detailed information like:

  • Currently no models that model sediment yield



Make a model that can:

  • Make a model that can:

    • Model erosion in a meso-scale catchment (20-200 km2)
    • Is based on physical processes
    • Has a significant hydrological component
    • Can be run for daily time-step
    • Requires input data readily available for most catchments
  • Eventually: A GIS- model that can be used by catchment managers and non-modeller-scientist



Landscape evolution model LAPSUS (Schoorl, 2002) (LandscApe ProcesS modelling at mUlti-dimensions and Scales)

  • Landscape evolution model LAPSUS (Schoorl, 2002) (LandscApe ProcesS modelling at mUlti-dimensions and Scales)

  • LAPSUS model models water and sediment routing



LAPSUS has water balance as a base.

  • LAPSUS has water balance as a base.

  • has been adapted to model sediment yield on a daily basis: LAPSUS-D:

    • Calibrated with daily precipitation and discharges.
    • gives good indication of possible sediment transport.


This new version of LAPSUS was tested on both a catchment in SW Poland and Mediterranean Israel up till now.

  • This new version of LAPSUS was tested on both a catchment in SW Poland and Mediterranean Israel up till now.

  • Upper Nysa Szalona:

  • South western Poland: Temperate climate,

  • 23 km2



Nahal Oren:

  • Nahal Oren:

  • Mediterranean climate

  • Carmel mountains

  • 20 km2





Because of smaller time step of 1 day:

  • Because of smaller time step of 1 day:

  • Basic assumption of all water leaving the catchment in 1 time step no longer valid:

  • Therefore:

  • Cut rainfall-runoff in two parts:

    • Surface runoff  leaves catchment in 1 day
    • Subsurface runoff  moves with 1 cell/day










No base flow

  • No base flow

  • But due to geology: deep drainage which is not accounted for in model

  • With few adaptations, which need to be refined:

    • Peak duration and peak volume modelled with good accuracy
  • Sediment calibration: good results

  • Now looking for longer record for validation



Meso-scale catchment (20-200 km2)

  • Meso-scale catchment (20-200 km2)

  • Hydrological component

  • Daily time-step

  • Calibration with the discharge at the outlet

    • Using only:
        • DEM (10 to 30 m pixel size)
        • soil map
        • land use map
        • daily discharge and precipitation data
        • A general idea of the soil depths in the catchment.
  • With this: calibration for water flow part:

  • good indication of possible sediment transport



Thanks!

  • Thanks!

  • Questions?



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