Nutrient Transport Modelling in the Daugava River Basin - DiVA Portal

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Description of parameter/input Name Unit Initial valueCalibratedValueReferenceLichens and wetlands 0.02Snow and ice 0Coniferous forest 0.009Mixed forest 0.009Deciduous forest 0.01Water 0.01Artificial surfacesN buildup rate on artificial surfaces n k kg/ha/day 0.101 Dai et al., 2000P buildup rate on artificial surfaces n k kg/ha/day 0.0112 Dai et al., 2001Point sourcesPoint N DP m kg/month 91000 Latvian Environment Agency, 2002Point P DP m kg/month 17000 Latvian Environment Agency, 200230
Appendix B. Determination of surface runoffSurface runoff is computed from weather data by the U.S. Soil Conservation Service’sCurve Number Equation (equation B1) (Dai et al., 2001).Qkt( Rt+ Mt− 0.2 ⋅ DSkt)=R + M + 0.8 ⋅ DSttkt2(B1)whereQ kt = surface runoff from land use k on day t [cm]R t = rainfall on day t [cm]M t = snowmelt on day t [cm]DS kt = detention parameter for land use k on day t [cm]Precipitation is assumed to be rain when the daily mean air temperature is more than0 °C.If there is a snow cover, snowmelt is computed by a degreeday equation:M= TC ⋅for T t > 0 °C (B2)tT twhereTC = temperature coefficient for snowmelt [cm/°C]T t = mean air temperature on day t [°C]The detention parameter DS kt is determined from a curve number CN kt :DSkt2540 − 25.4CN= kt(B3)Curve numbers are determined from a function of antecedent moisture as shown infigure B1. Curve numbers for antecedent moisture conditions 1 (driest), 2 (average) and3 (wettest) are CN1 k , CN2 k and CN3 k respectively.31
Page 1 and 2: UPTEC W05 009Examensarbete 20 pFebr
Page 3 and 4: Nyckelord: avrinning, näringsämne
Page 6 and 7: APPENDIX C. DETERMINATION OF POTENT
Page 8 and 9: simulation system CatchmentSim. The
Page 10 and 11: Figure 1. The hydrological part of
Page 12 and 13: TemperaturePrecipitation20.00120deg
Page 14 and 15: 3.2 MODEL DESCRIPTION3.2.1 An overv
Page 16 and 17: Groundwater discharge to the river
Page 18 and 19: Groundwater nutrient loadsThe groun
Page 20 and 21: There is therefore no guarantee tha
Page 22 and 23: a) Streamflow, calibration periodb)
Page 24 and 25: 4.2 IMPACT OF THE CURVE NUMBER ON N
Page 26 and 27: the chosen value is a very rough ap
Page 28 and 29: all cultivated land will have winte
Page 30 and 31: HELCOM, 2004a. 30 years of protecti
Page 32 and 33: Appendix A. Input data and paramete
Page 34 and 35: Description of parameter/input Name
Page 38 and 39: moisture.Figure B1. Selection of cu
Page 40 and 41: wherea t = rainfall erosivity coeff
Page 42 and 43: Appendix F. Regression lines of rep

Nutrient Transport Modelling in the Daugava River Basin - DiVA Portal

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