private void CalcRunoff_USDA_SoilConservationService(double WaterForRunoff, SoilWaterSoil SoilObject)
{
//private void soilwat2_scs_runoff(double Rain, double Runon, double TotalInterception, ref double Runoff)
// {
//cn2_new (output)
//Runoff (output)
double cn; //! scs curve number
double cn1; //! curve no. for dry soil (antecedant) moisture
double cn3; //! curve no. for wet soil (antecedant) moisture
double cnpd; //! cn proportional in dry range (dul to ll15)
double s; //! potential max retention (surface ponding + infiltration)
double xpb; //! intermedite variable for deriving runof
double[] runoff_wf; //! weighting factor for depth for each layer
double dul_fraction; // if between (0-1) not above dul, if (1-infinity) above dul
double cover_fract; //! proportion of maximum cover effect on runoff (0-1)
double cover_reduction = 0.0;
double tillage_fract;
double tillage_reduction = 0.0; //! reduction in cn due to tillage
runoff_wf = new double[SoilObject.num_layers];
soilwat2_runoff_depth_factor(SoilObject, ref runoff_wf);
cnpd = 0.0;
foreach (Layer lyr in SoilObject)
{
dul_fraction = MathUtilities.Divide((lyr.sw_dep - lyr.ll15_dep), (lyr.dul_dep - lyr.ll15_dep), 0.0);
cnpd = cnpd + dul_fraction * runoff_wf[lyr.number - 1]; //zero based array.
}
cnpd = cons.bound(cnpd, 0.0, 1.0);
//reduce cn2 for the day due to the cover effect
//nb. cover_surface_runoff should really be a parameter to this function
cover_fract = MathUtilities.Divide(cover_surface_runoff, coverCnCov, 0.0);
cover_fract = cons.bound(cover_fract, 0.0, 1.0);
cover_reduction = coverCnRed * cover_fract;
cn2_new = _cn2_bare - cover_reduction;
//tillage reduction on cn
//nb. tillage_cn_red, tillage_cn_rain, and tillage_rain_sum, should really be parameters to this function
if (tillageCnCumWater > 0.0)
{
//We minus 1 because we want the opposite fraction.
//Tillage Reduction is biggest (CnRed value) straight after Tillage and gets smaller and becomes 0 when reaches CumWater.
//unlike the Cover Reduction, where the reduction starts out smallest (0) and gets bigger and becomes (CnRed value) when you hit CnCover.
tillage_fract = MathUtilities.Divide(cumWaterSinceTillage, tillageCnCumWater, 0.0) - 1.0;
tillage_reduction = tillageCnRed * tillage_fract;
cn2_new = cn2_new + tillage_reduction;
}
else
{
//nothing
}
//! cut off response to cover at high covers if p%cn_red < 100.
cn2_new = cons.bound(cn2_new, 0.0, 100.0);
cn1 = MathUtilities.Divide(cn2_new, (2.334 - 0.01334 * cn2_new), 0.0);
cn3 = MathUtilities.Divide(cn2_new, (0.4036 + 0.005964 * cn2_new), 0.0);
cn = cn1 + (cn3 - cn1) * cnpd;
// ! curve number will be decided from scs curve number table ??dms
s = 254.0 * (MathUtilities.Divide(100.0, cn, 1000000.0) - 1.0);
xpb = WaterForRunoff - 0.2 * s;
xpb = Math.Max(xpb, 0.0);
//assign the output variable
Runoff = MathUtilities.Divide(xpb * xpb, (WaterForRunoff + 0.8 * s), 0.0);
//sv- I added these output variables
cn_red_cov = cover_reduction;
cn_red_till = tillage_reduction;
//bound check the ouput variable
cons.bound_check_real_var(Runoff, 0.0, WaterForRunoff, "runoff");
}
//Initialise the Accumulating Variables
public void InitialiseAccumulatingVars(SoilWaterSoil SoilObject, IClock Clock)
{
//reset the accumulated Evap variables (sumes1, sumes2, t)
//nb. sumes1 -> is sum of es during stage1
//used in the SoilWater Init, Reset event
// soilwat2_soil_property_param()
//assign u and cona to either sumer or winter values
// Need to add 12 hours to move from "midnight" to "noon", or this won't work as expected
if (DateUtilities.WithinDates(winterDate, Clock.Today, summerDate))
{
cona = winterCona;
u = winterU;
}
else
{
cona = summerCona;
u = summerU;
}
//private void soilwat2_evap_init()
// {
//##################
//Evap Init --> soilwat2_evap_init (), soilwat2_ritchie_init()
//##################
//soilwat2_ritchie_init();
//*+ Mission Statement
//* Initialise ritchie evaporation model
double swr_top; //! stage 2 evaporation occurs ratio available sw potentially available sw in top layer
Layer top = SoilObject.GetTopLayer();
//! set up evaporation stage
swr_top = MathUtilities.Divide((top.sw_dep - top.ll15_dep), (top.dul_dep - top.ll15_dep), 0.0);
swr_top = cons.bound(swr_top, 0.0, 1.0);
//! are we in stage1 or stage2 evap?
if (swr_top < cons.sw_top_crit)
{
//! stage 2 evap
sumes2 = cons.sumes2_max - (cons.sumes2_max * MathUtilities.Divide(swr_top, cons.sw_top_crit, 0.0));
sumes1 = u;
t = MathUtilities.Sqr(MathUtilities.Divide(sumes2, cona, 0.0));
}
else
{
//! stage 1 evap
sumes2 = 0.0;
sumes1 = cons.sumes1_max - (cons.sumes1_max * swr_top);
t = 0.0;
}
}
