transform {RHMS}

Transforms a rainfall event to runoff

Description

This function transforms an excess rainfall event to a direct runoff hydorgraph.

Usage

transform(rainfall,transformMethod,transformParams,Area,UH,simulation)

Arguments

rainfall

an object inherited from loss function

transformMethod

a string: the type of transformation method. available types: "SCS", "snyder", and "user". default to "SCS"

transformParams

a list of parameters associated to the selcted type of transformMethod:

• Tlag for "SCS" method

• Ct, Cp, L, and Lc for "snyder" method

Area

the area of drainage basin (Km^2)

UH

a data.frame: must be provided when transformMethod is set to "user". UH is the ordinates of a user defined UH by the which its first collumn is time (Hr) and the second collumn includes flow rates (cms)

simulation

a list of simulation time and dates as below:

• start: the date which simulation starts, must be in 'YYYY-MM-DD' format

• start: the date which simulation ends, must be in 'YYYY-MM-DD' format

• by: the interval of each steps in seconds

Value

Hydrogaph of direct runoff

Author(s)

Rezgar Arabzadeh

See Also

sim

Examples

Area=200
lossMethod<-"SCS"
lossParams<-list(CN=65)
transformMethod<-c("snyder","SCS","user")
simulation<-list(start='2000-01-01',end='2000-01-7',by=7200)
precipitation<-sin(seq(0.1,pi-0.1,length.out=10))*20
transformParams=list(Tlag=4,Cp=0.15,Ct=2,L=100,Lc=15)
UH<-data.frame(t=1:20,q=sin(seq(0,pi,length.out=20))*1)

SCS_loss<-loss(precipitation,lossMethod,lossParams)

snyder_transformation<-transform(rainfall=SCS_loss,
                                 transformMethod=transformMethod[1],
                                 transformParams,Area,UH=NA,simulation)
SCS_transformation   <-transform(rainfall=SCS_loss,
                                 transformMethod=transformMethod[2],
                                 transformParams,Area,UH=NA,simulation)
user_transformation  <-transform(rainfall=SCS_loss,
                                 transformMethod=transformMethod[3],
                                 transformParams,Area,UH,simulation)