Package net.simplace.sim.components.experimental.runoff

Class CNEquations

java.lang.Object
net.simplace.sim.components.experimental.runoff.CNEquations
public class CNEquations extends Object
Shared equations for the components calculating runoff using the SCS curve number method and variants thereof. References: Cronshey, R., 1986. Urban hydrology for small watersheds (No. TR-55). US Dept. of Agriculture, Soil Conservation Service, Engineering Division. Neitsch, S.L., Arnold, J.G., Kiniry, J.R., Williams, J.R., 2011. Soil & Water Assessment Tool, Theoretical Documentation, Version 2009 (No. TR-406).
Author:
Roelof Oomen

  • Constructor Summary

    Constructors
    Constructor
    Description
    CNEquations()
     

  • Method Summary

    Modifier and Type
    Method
    Description
    protected static double
    CN(double S)
    Curve number calculated from the retention parameter (this is SWAT2009 eq. 2:1.1.2 rearranged).
    protected static double
    CN2s(double CN2, double slope)
    Slope adjustment of curve number 2 SWAT2009 eq. 2:1.1.12
    protected static double
    CN2slope(double CN2, Double slope)
    Slope adjustment of curve number 2 - if slope is null, no correction is made
    protected static double
    Q_surf(double R, double S)
    Surface runoff SWAT2009 eq. 2:1.1.1
    protected static double
    S(double CN)
    Potential maximum retention after runoff begins (unadjusted) SWAT2009 eq. 2:1.1.2
    protected static double
    S_3(double CN2)
    Minimum retention parameter value, i.e. retention parameter for CN3 SWAT2009 pg. 104
    protected static double
    S_ET(double S_max, double S_prev, double ET0, double CNcoef, double CN2, double R, double Q_surf)
    Retention parameter that varies with plant evapotranspiration SWAT2009 eq. 2:1.1.9
    protected static double
    S_frz(double S_max, double S)
    Retention parameter adjustment for frozen soil.
    protected static double
    S_max(double CN2)
    Maximum retention parameter value, i.e. retention parameter for CN1 SWAT2009 pg. 104
    protected static double
    S_SW(double S_max, double SW, double w1, double w2)
    Retention parameter that varies with soil water content SWAT2009 eq. 2:1.1.6
    protected static double
    w1(double FC, double S_max, double S_3, double w2)
    Shape coefficient 1 SWAT2009 eq. 2:1.1.7
    protected static double
    w2(double FC, double SAT, double S_max, double S_3)
    Shape coefficient 2 SWAT2009 eq. 2:1.1.8

    Methods inherited from class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

  • Constructor Details

    • CNEquations

      public CNEquations()

  • Method Details

    • Q_surf

      protected static double Q_surf(double R, double S)
      Surface runoff SWAT2009 eq. 2:1.1.1
      Parameters:
      R -
      S -
      Returns:

    • S

      protected static double S(double CN)
      Potential maximum retention after runoff begins (unadjusted) SWAT2009 eq. 2:1.1.2
      Parameters:
      CN -
      Returns:

    • CN

      protected static double CN(double S)
      Curve number calculated from the retention parameter (this is SWAT2009 eq. 2:1.1.2 rearranged). Used to determine the equivalent Curve Number after adjusting S for slope, antecedent moisture conditions, etc. SWAT2009 eq. 2:1.1.11
      Parameters:
      S -
      Returns:

    • S_max

      protected static double S_max(double CN2)
      Maximum retention parameter value, i.e. retention parameter for CN1 SWAT2009 pg. 104
      Parameters:
      CN2 -
      Returns:

    • S_3

      protected static double S_3(double CN2)
      Minimum retention parameter value, i.e. retention parameter for CN3 SWAT2009 pg. 104
      Parameters:
      CN2 -
      Returns:

    • CN2s

      protected static double CN2s(double CN2, double slope)
      Slope adjustment of curve number 2 SWAT2009 eq. 2:1.1.12
      Parameters:
      CN2 - curve number 2
      slope - as fraction
      Returns:

    • CN2slope

      protected static double CN2slope(double CN2, Double slope)
      Slope adjustment of curve number 2 - if slope is null, no correction is made
      Parameters:
      CN2 - curve number 2
      slope - in %
      Returns:

    • w1

      protected static double w1(double FC, double S_max, double S_3, double w2)
      Shape coefficient 1 SWAT2009 eq. 2:1.1.7
      Parameters:
      FC -
      S_max -
      S_3 -
      w2 -
      Returns:

    • w2

      protected static double w2(double FC, double SAT, double S_max, double S_3)
      Shape coefficient 2 SWAT2009 eq. 2:1.1.8
      Parameters:
      FC -
      SAT -
      S_max -
      S_3 -
      Returns:

    • S_SW

      protected static double S_SW(double S_max, double SW, double w1, double w2)
      Retention parameter that varies with soil water content SWAT2009 eq. 2:1.1.6
      Parameters:
      S_max -
      SW -
      w1 -
      w2 -
      Returns:

    • S_ET

      protected static double S_ET(double S_max, double S_prev, double ET0, double CNcoef, double CN2, double R, double Q_surf)
      Retention parameter that varies with plant evapotranspiration SWAT2009 eq. 2:1.1.9
      Parameters:
      CN -
      Returns:

    • S_frz

      protected static double S_frz(double S_max, double S)
      Retention parameter adjustment for frozen soil. SWAT2009 eq. 2:1.1.10
      Parameters:
      S -
      Returns: