Some of my current research:

Modeling sediment delivery on a daily basis

for meso-scale catchments:

a new tool: LAPSUS-D By: Saskia Keesstra and Arnaud Temme Wageningen University (Netherlands)with many thanks to:Agnieszka Czajka (University of Silesia)

Background (1)

Background Aims Study area Methodology Results Conclusions Outlook

• For management purposes important to assess sediment yield of a catchment.

• Currently: models designed for estimating sediment yield either:– give very detailed storm-based information– or yearly averages.

Background (2)

• 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.

Background Aims Study area Methodology Results Conclusions Outlook

Background (3)

• BUT: yearly averages models: ignore lot of other detailed information like:– daily discharge – precipitation data.

• Currently no models that model sediment yield– On temporal scale of one day– On spatial scale of a meso-scale catchment, without

making use of very detailed input data.

Background Aims Study area Methodology Results Conclusions Outlook

Research aim (1)

• 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

Background Aims Study area Methodology Results Conclusions Outlook

Research aim (2)

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

• LAPSUS model models water and sediment routing

Background Aims Study area Methodology Results Conclusions Outlook

Research aim (3)

• 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.

Background Aims Study area Methodology Results Conclusions Outlook

Study area (1)

• 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

Background Aims Study area Methodology Results Conclusions Outlook

Study area (2)

• Nahal Oren: • Mediterranean climate • Carmel mountains• 20 km2

Background Aims Study area Methodology Results Conclusions Outlook

J.M. SchoorlLaboratory of Soil Science & Geology

Modelling framework

RainfallErodibilityInfiltration

LanduseGeologySoil type Soil depthDEM

Scenarios

ErosionDepositionchanged DEM

LAPSUS model

Run-onRun-off

Changes to LAPSUS

Background Aims Study area Methodology Results Conclusions Outlook

• 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

Current status of model development

Background Aims Study area Methodology Results Conclusions Outlook

Precipitation

Interception by vegetation

Surface storage

Time step 1 Time step 2

Infiltration

Maximum infiltration rate

Maximum storage capacity Surface runoff

Groundwater Darcy: slope of groundwater level

Multiple flow: slope of surface

Run on

Infiltration Surface runoff

Run on

Explain water stocks, flows and losses:Stocks:Surface storage•Storage in unsaturated zone.Flows:Infiltration•Hortonian overland flow•Saturated overland flow•Groundwater to surface flow•Groundwater to groundwaterLosses:Soil evaporation• Interception

Repetition of processes in time step 1

Precipitation

Methodology: calibration in Poland

Background Aims Study area Methodology Results Conclusions Outlook

• With limited input no full hydrological simulation• Specially baseflow not well simulated.• BUT: only peak discharge is important for sediment

transport• Therefore focus on peak discharge

Results of calibration in Poland

Background Aims Study area Methodology Results Conclusions Outlook

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precipitation LAPSUS modelled discharge measured discharge evaporation

Results of calibration

Background Aims Study area Methodology Results Conclusions Outlook

• Our set calibration tool gave satifactory results as:• Peak height and peak duration and peak volume

was modelled with good accuracy

Calibration in Israel

• 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

Background Aims Study area Methodology Results Conclusions Outlook

Summary LAPSUS-D

• 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

Background Aims Study area Methodology Results Conclusions Outlook

Thanks!

Questions?