By Bioforsk SEALINK Team

Transkript

1 By Bioforsk SEALINK Team Csilla Farkas Johannes Deelstra Per Stålnacke SEALINK Meeting September, 2009 Bioforsk

2 Calibration period: 1 January, December, 1999 Validation period: 1 January, December, 2007 Land use types: Forest (31%) Grass (2%) Arable, No Autumn Tillage (18%) Arable, Autumn Tillage (41%) Wetland (0% between ; to be parameterised for the period of ) Urban (8%) Catchment structure No subcatchments, one reach No effluent No abstraction

3 1. Catchment and reach information Catchment area, reach length 2. Data on fertiliser application NO3 fertilisation input files 3. Crop data Multiple growth period input files 4. Soil data From reference soil profiles, belonging to the agricultural area Soils of the forest area were represented by a chosen reference soil profile from an arable land Setting up parameters (soil water deficit maximum; total/available water)

4 1. Driving variables HBV model run output, provided by NVE Soil moisture deficit; effective rainfall; air temperature; precipitation 2. Reference data Discharge measurements (daily data) Nitrate concentration data (composite sampling; approx. every 14 days) Changes with respect to previous runs, while trying to inprove the hydrology: Using new HBV output from NVE, obtained using manually recorded precipitation data Assuming the contribution of drain pipes as part of the water, rapidly flashed out from the catchment (discussion with Deborah L.)

5 1. Parameterisation Available data from the Skuterud catchment and reach Literature review Expert assumptions 2. Calibration procedure Stepwise calibration approach (flow; flow&nitrate) Incorporation of sensitivity analyses results 3. Validation procedure 4. Scenario analyses

6 Main hydrological parameters, against which the model appeared to be very sensitive Flow parameters a an b Base flow index Soil moisture deficit maximum previous, automatic raingauge Soil reactive zone time constant Ratio of total to available water in soil Groundwater sustainable flow (!) Rainfall excess proportion Direct runoff time constant (AtTill) current, manual prec. register Direct runoff time constant (Forest) Soil reactive zone time constant (Forest) From flow procesess (as dominants) towards parameters, controllin partioning of water

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8 Hydrology and NO3 optimized

9 Simulated N_NO3 Simulated (kg) Monthly sums, y = x R² = N_NO3 measured (kg) Summer period R² = Summer period R² = R² = R² = Winter period Spring period Autumn period R² = Measured

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14 Applying INCA-SED to the Skuterud catchment

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16 1. Driving variables HBV model run output, provided by NVE Soil moisture deficit; effective rainfall; air temperature; precipitation BUT! Switch between HER and rainfall available 2. Reference data Discharge measurements (daily data) Measured suspended sediment concentrations (composite sampling; approx. every 14 days)

17 1. Catchment and reach information Catchment area, reach length Mean slope of the catchment Slope of the reach Average channel width 2. Soil data From reference soil profiles, belonging to the agricultural area Soils of the forest area were represented by a chosen reference soil profile from an arable land Setting up parameters (soil water deficit maximum; total/available water) Detailed data on soil textureal classes from soil profile descriptions 3. Vegetation index Set according to available literature data (= 1 for forest, grass and urban; and = 7 for cereals)

18 4. Hydrological parameters The hydrological was fully set in accordance with the calibrated INCA-N model parameters. The most important data are: o o o Parameters, controlling the partitioning of water between the three pools (surface water; soil water and groundwater) ; rainfall excess proportion; maximum infiltration rate etc.) Parameters, controlling the residence time of water in each of the pools (direct runoff, soil water and groundwater residence times) Parameters of the flow-velocity relationship 5. Parameters, controlling sediment availability in the catchment Splash detachment parameters set according to literature data and corrected in order to get realistic amount of stored sediments in the catchment 6. Calibration parameters have been calibrated, using values within the suggested range and on the base of INCA-SED meeting in NIVA (consultation with Deborah L.)

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20 Simulated kg/ha Simulated kg/ha Yearly sums SS SS SS SS measured sim measured sim kg/ha kg/ha kg/ha kg/ha jan-feb 2 10 mar-apr may-aug sep-nov dec-feb mar-apr may-aug sep-nov dec-feb 2 11 mar-apr may-aug sep-nov dec-feb mar-apr may-aug sep-nov dec-feb mar-apr may-aug sep-dec y = x R² = INCA-SED, seasonal sums of sediment transport Calculated from measured data kg/ha INCA-SED, seasonal sums of sediment transport y = x R² = Calculated from measured data kg/ha

21 The improved driving variables, received from the NVE were used to improve the calibration of the INCA hydrology. In general, the output of the INCA-N and INCA-SED models for the Skuterud catchment are reasonable and meet our expectations Further attempts are needed to find out, how to use INCA-N and INCA- SED output graphs and tables for improving models performance The INCA-N model could give good results for autumn and especially winter periods, but failed to simulate N-transport processes during snowmelt The calibration of the INCA-SED model for winter conditions has to be improved considerably

22 Thank you for attention!