# hydraulic_diffusivity: Soil water Retantion Curve and Unsaturated Hydraulic... In ecor/soilwater: Implementation of Parametric Formulas for Soil Water Retention or Conductivity Curve

## Description

Soil Water Retention Curve 'swc', Hydraulic Conductivity 'khy' , Soil Water Capacity 'cap' , Soil Water (Hydraulic) Diffusivity 'diffusivity'

## Usage

 ``` 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15``` ```swc(psi = 0.5, alpha = 1, n = 1.5, m = 1 - 1/n, theta_sat = 0.4, theta_res = 0.05, psi_s = -1/alpha, lambda = m * n, saturation_index = FALSE, type_swc = c("VanGenuchten", "BrooksAndCorey"), ...) khy(psi = 0.5, v = 0.5, ksat = 0.01, alpha = 1, n = 1.5, m = 1 - 1/n, theta_sat = 0.4, theta_res = 0.05, psi_s = -1/alpha, lambda = m * n, b = NA, type_swc = "VanGenuchten", type_khy = c("Mualem", "BrooksAndCorey"), ...) cap(psi = 0.5, alpha = 1, n = 1.5, m = 1 - 1/n, theta_sat = 0.4, theta_res = 0.05, type_swc = "VanGenuchten", ...) diffusivity(psi = 0.5, v = 0.5, ksat = 0.01, alpha = 1, n = 1.5, m = 1 - 1/n, theta_sat = 0.4, theta_res = 0.05, ...) ```

## Arguments

 `psi` soil wwater pressure head `alpha` inverse of a length - scale parameters in Van Genuchten Formula `n` shape parameter in Van Genuchten Formula `m` shape parameter in Van Genuchten Formula. Default is `1-1/n` `theta_sat` saturated water content `theta_res` residual water content `psi_s` psi_s value (capillary fringe) in Brook and Corey formula. It is used in case `type_swc` and/or `type_khy` are equal to `BrooksAndCorey`. `lambda, b` lambda and b exponents in Brook and Corey formula. It is used in case `type_swc` and/or `type_khy` are equal to `BrooksAndCorey`. `saturation_index` logical index, If `TRUE` (Default) the function `swc()` returns soil water content, otherwise a saturation index between 0 and 1. `type_swc` type of Soil Water Retention Curve. Default is `"VanGenuchten"` and actually the only implemented type `...` further arguments which are passed to `swc()` and `khy()` `v` exponent in Mualem Formula for Hydraulic Conductivity `ksat` saturated hydraulic conductivity `type_khy` type of Soil Hydraulic Conductivity Curve. Default is `"Mualem"` and actually the only implemented type

## Examples

 ``` 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43``` ```library(soilwater) soiltype <- c("sand","silty-sand","loam","clay") theta_sat <- c(0.44,0.39,0.51,0.48) theta_res <- c(0.02,0.155,0.04,0.10) alpha <- c(13.8,6.88,9.0,2.7) # 1/meters n <- c(2.09,1.881,1.42,1.29) m <- 1-1/n v <- array(0.5,length(soiltype)) ks <- c(1.5e-1,1e-4*3600,3.3e-2,4.1e-4)/3600 # meters/seconds psi <- -(1:2000)/1000 D <- as.data.frame(array(0.1,c(length(psi),length(soiltype)))) names(D) <- soiltype for (it in names(D)) { i=which(names(D)==it) D[,i] <- diffusivity(psi=psi, v=v[i],ksat=ks[i],alpha=alpha[i], n=n[i],m=m[i],theta_sat=theta_sat[i], theta_res=theta_res[i]) } # plot diffusivity on log scale lty <- 1:length(names(D) ) plot(psi,D[,1],lty=lty[1],main="Diffusvity vs psi",xlab="psi [m]", ylab="D [m^2/s]",type="l",ylim=range(D),ylog=TRUE) for (i in 2:ncol(D)) { lines(psi,D[,i],lty=lty[i]) } legend("topleft",lty=lty,legend=names(D)) Dinv <- 1/D # pot diffusivity on log scale lty <- 1:length(names(D) ) plot(psi,Dinv[,1],lty=lty[1],main="1/Diffusvity vs psi", xlab="psi [m]",ylab="1/D [s/m^2]",type="l",ylim=range(Dinv),ylog=TRUE) for (i in 2:ncol(Dinv)) { lines(psi,Dinv[,i],lty=lty[i]) } legend("topright",lty=lty,legend=names(D)) ```

ecor/soilwater documentation built on May 15, 2019, 10:06 p.m.