EcoHydRology (version 0.4.9)

SoilStorage: Calculating S in the Curve Number Equation from soil water content

Description

This function calculates S, used in the SCS-CN equation, from the water content of the soil.

Usage

SoilStorage(S_avg, field_capacity, soil_water_content, porosity)

Arguments

S_avg

Average S, as used normally in the CN equation, calculated from the curve number, which is based on land-use. This is in units of depth, often mm or inches

field_capacity

field capacity - the amount of water that a soil can hold after drainage. (fraction)

soil_water_content

Soil water content (fraction) on a given day.

porosity

Saturated water content, approximately equal to the porosity of a soil (fraction)

See Also

SoilStorageSWAT

Examples

##---- Should be DIRECTLY executable !! ----
##-- ==>  Define data, use random,
##--	or do  help(data=index)  for the standard data sets.

## The function is currently defined as
function(S.avg,field.capacity, soil.water.content, porosity){
w2<-(log(1-(field.capacity/(1-0.4348*S.avg/(2.381*S.avg)))-field.capacity)-log(1-(porosity/(1-2.54/(2.381*S.avg)))-porosity
))/(porosity-field.capacity)##
w1<-log(1-field.capacity/(1-0.4348*S.avg/(2.381*S.avg))-field.capacity)+w2*field.capacity
return(2.381*S.avg*(1-(soil.water.content/(soil.water.content+exp(w1-w2*soil.water.content)))))
  }