net.simplace.sim.components.experimental.runoff.CNEquations
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).
public class CNEquations {
// Public Constructors
public CNEquations();
// Class Methods protected static double
Q_surf(double R, double S);
Surface runoff
SWAT2009 eq. 2:1.1.1
returns protected static double
S(double CN);
Potential maximum retention after runoff begins (unadjusted)
SWAT2009 eq. 2:1.1.2
returns 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
returns protected static double
S_max(double CN2);
Maximum retention parameter value, i.e. retention parameter for CN1
SWAT2009 pg. 104
returns protected static double
S_3(double CN2);
Minimum retention parameter value, i.e. retention parameter for CN3
SWAT2009 pg. 104
returns protected static double
CN2s(double CN2, double slope);
Slope adjustment of curve number 2
SWAT2009 eq. 2:1.1.12
- CN2 curve number 2
- slope as fraction
returns protected static double
CN2slope(double CN2, Double slope);
Slope adjustment of curve number 2
- if slope is null, no correction is made
- CN2 curve number 2
- slope in %
returns protected static double
w1(double FC, double S_max, double S_3, double w2);
Shape coefficient 1
SWAT2009 eq. 2:1.1.7
returns protected static double
w2(double FC, double SAT, double S_max, double S_3);
Shape coefficient 2
SWAT2009 eq. 2:1.1.8
returns 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
returns 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
returns protected static double
S_frz(double S_max, double S);
Retention parameter adjustment for frozen soil.
SWAT2009 eq. 2:1.1.10
returns
}
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