ksat: Estimating saturated hydraulic conductivity with water...

In gowusu/vadose: The estimation of saturated hydraulic conductivity and soil water retention Curves in the vadose zone

Description

This function estimates Ks based on 5 models that include (see references) Guarracino (2007), Nasta et al (2013), Mishra et al(1990), Rawls et al(1982) and Saxton & Rawls (2006). The model can also return tabulated Ks of Carsel and Parrish (1988) when soil texture is given as a "model" parameters.

Usage

ksat(ths = NULL, thr = 0, alpha = NULL, hb = NULL, th33 = NULL,
  th1500 = NULL, C = NULL, f = NULL, para = NULL, n = NULL,
  model = "nvr")

## Default S3 method:
ksat(ths = NULL, thr = 0, alpha = NULL, hb = NULL,
  th33 = NULL, th1500 = NULL, C = NULL, f = NULL, para = NULL,
  n = NULL, model = "nvr")

Arguments

ths	numeric. The saturated soil water content [m3/m3].
thr	numeric. Residual volumetric soil water content. This can be calibrated.
alpha	van Genuchten's water retention parameter. It is equal to 1/hb
hb	the bubbling capillary pressure parameter of Brooks and Corey. It is equal to 1/apha.
th33	The water content at field capacity [m3/m3] .i.e metric potential of 33 kPa
th1500	The water content at wilting point [m3/m3] i.e metric potential of 1500 kPa
C	clay percentage
f	porosity
para	a parameter for each model
n	van Genuchten's n that is realted to pore-size distribution.
model	model type. It can take "Nasta" (default), "Mishra", "RAWLS", "rawls2006", "Guarracino".

Value

• Ks: saturated hydraulic conductivity

• para: soil parameters

References

• Guarracino, L. (2007). Estimation of saturated hydraulic conductivity Ks from the van Genuchten shape parameter. Water Resour. Res., 43. doi: doi:10.1029/2006WR005766

• Paolo Nasta, Jasper A. Vrugt, & Romano, N. (2013). Prediction of the saturated hydraulic conductivity from Brooks and Corey's water retention parameters. WATER RESOURCES RESEARCH, 49. doi: doi:10.1002/wrcr.20269

• Mishra, S., & Parker, J. C. (1990). On the relation between saturated conductivity and capillary retention characteristics. Ground Water, 28, 775-777.

• Rawls, W. J., Brakensiek, D. L., & Saxon, K. E. (1982). Estimation of soil water properties. Transactions of the ASAE, 25, 1316-1320.

• Saxton, K. E., & Rawls, W. J. (2006). Soil Water Characteristic Estimates by Texture and Organic Matter for Hydrologic Solutions. SOIL SCI. SOC. AM. J., 70. doi: 10.2136/sssaj2005.0117

Examples

data=read.csv(system.file("ext","sys","retentionVG.csv",package="vadose"))
mod<-vg(data=data,h="h",theta="theta",thr=0.1, ths=0.1, alp=0.1, n=1,Ks="nvr")
nvr=ksat(ths=mod$ths,hb=1/mod$alp,n=mod$n-1,model="Nasta")
print(nvr)
g=ksat(ths=mod$ths,alpha=mod$alp,model="Guarracino")
print(g$Ks) 
soil=ksat(ths=mod$ths,alpha=mod$alp,model="Clay")
soil=ksat(para="soil",model="Clay")
mp=ksat(ths=mod$ths,alpha=mod$alp,model="Mishra")
print(mp)
r=ksat(ths=mod$ths,hb=1/mod$alp,n=mod$n-1,model="RAWLS",thr=mod$thr,f=mod$ths,para=86)
print(r)
sr=ksat(ths=mod$ths,th33=predict(mod,33),th1500=predict(mod,1500),model="rawls2006")
print(sr)

gowusu/vadose documentation built on May 17, 2019, 7:59 a.m.