R: Lumped Variable Source Area (VSA) Watershed Model
Lumped_VSA_model
R Documentation
Lumped Variable Source Area (VSA) Watershed Model
Description
This model calculates streamflow and approximate saturated area percentage contributing to overland flow. It was developed in saturation-excess dominated watersheds, and is based on the Thornthwaite-Mather water budget and SCS Curve Number approach for overland runoff.
Average watershed soil depth (mm)
Not needed if SAT and AWC depth entered directly
SATper
Porosity of the soil (volumetric fraction, 0-1)
Not needed if SAT (porosity depth) entered directly
AWCper
Available water capacity, Field capacity - wilting point (volumetric fraction, 0-1)
Not needed if AWC entered directly
percentImpervious
Percent of the watershed that is impervious (percentage, 0-100
no_wet_class
Number of wetness classes to distribute runoff over. Default is 10.
Tp
Time to peak of hydrograph (hours)
latitudeDegrees
latitude (degrees)
albedo
Average surface albedo, defaults to average 0.23
StartCond
Watershed conditions before first day of run (options are "wet", "dry", "avg")
PETin
# User has the option to enter PET values (mm/day), otherwise this will be estimated from Priestley-Taylor equation, estimating radiation from temperature
AWC
# AWC depth (mm)
SAT
Porosity depth (mm)
SW1
Soil water on the first day (depth, mm)
BF1
Baseflow on the first day (mm/day)
PETcap
Cutoff for maximal PET allowed per day (mm)
rec_coef
Baseflow recession coefficient
Se_min
Minimal daily CN S value. (mm)
C1
Coefficient relating daily Curve Number S to soil water
Ia_coef
Initial abstraction coefficient for CN-equation. (range ~ 0.05 - 0.2)
PreviousOutput
If the model is run repeatedly, previous output can be provided so that the model only needs to calculate from that point forward.
runoff_breakdown
The proportion of runoff that reaches the outlet on a given day after the storm event. Can be calculated from Tp
Details
The model expects continuous input on a daily time-step, since the soil-water is calculated over time, and affects the amount of runoff that will be generated after a storm.
Also, note that precipitation values are actually Rain + Snowmelt (mm). Users can use the snowmelt function to determine this if needed.
Value
Returns a data frame with modeled streamflow, baseflow, ET, and maximum wetness class generating runoff for all dates. Soil water and other modeled intermediate results are also returned. All flow values (modeled_flow, baseflow, OverlandFlow, ShallowInterflow, totQ, quickflow_combined, impervRunoff, excess) are in depth of flow per day (mm/d)
Warning
This function cannot handle NA values in input, and can only be run for a daily time-step.
If Tx < Tn for any day, this will produce an error.
Currently, the crop coefficients used to estimate PET are specific for deciduous northeastern USA.
Note
This function is under development and might change substantially in further versions.
Author(s)
Josephine Archibald
References
Archibald, J.A., B.P. Buchanan, D.R. Fuka, C.B Georgakakos, S.W. Lyon, M.T. Walter. A simple, regionally parameterized model for predicting nonpoint source areas in the Northeastern US. Submitted to Journal of Hydrology: Regional Studies
Schneiderman EM. Steenhuis TS, Thongs DJ, Easton ZM, Zion MS, Neal AL, Mendoza GF, Walter MT. 2007. Incorporating variable source area hydrology into a curve-number-based watershed model. Hydrological Processes. 21: 3420-3430
Shaw, SB, MT Walter. 2009. Improving runoff risk estimates: Formulating runoff as a bivariate process using the SCS curve number method. Water Resources Research. 45
Thornthwaite CW, JR Mather. 1957 Instructions for computing potential evapotranspiration and water balance. Publ Climatol 3: 183-311
United States Department of Agriculture (USDA). (1986). SCS publication Technical Release 55: Urban Hydrology for Small Watersheds. Natural Resources Conservation Service
Weiler K. Unpublished. Determination of the Linear Bedrock Coefficient From Historical Flow Data
See Also
PET_fromTemp
Examples
data(OwascoInlet)
# First get rain and snow-melt input:
rsm <- SnowMelt(Date=OwascoInlet$date, precip_mm=OwascoInlet$P_mm, Tmax_C=OwascoInlet$Tmax_C,
Tmin_C=OwascoInlet$Tmin_C, lat_deg=42.66)
# Calculate streamflow based on watershed characteristics:
Results <- Lumped_VSA_model(dateSeries = OwascoInlet$date, P = rsm$Rain_mm+rsm$SnowMelt_mm,
Tmax=OwascoInlet$Tmax_C, Tmin = OwascoInlet$Tmin_C, latitudeDegrees=42.66, Tp = 5.8, Depth = 2010,
SATper = 0.27, AWCper = 0.13, StartCond = "wet")
# View results:
hydrograph(streamflow=ConvertFlowUnits(cms=OwascoInlet$Streamflow_m3s, WA=106, AREAunits="mi2"),
timeSeries=OwascoInlet$date, streamflow2=Results$modeled_flow, precip=rsm$Rain_mm+rsm$SnowMelt_mm)
Results
R version 3.3.1 (2016-06-21) -- "Bug in Your Hair"
Copyright (C) 2016 The R Foundation for Statistical Computing
Platform: x86_64-pc-linux-gnu (64-bit)
R is free software and comes with ABSOLUTELY NO WARRANTY.
You are welcome to redistribute it under certain conditions.
Type 'license()' or 'licence()' for distribution details.
R is a collaborative project with many contributors.
Type 'contributors()' for more information and
'citation()' on how to cite R or R packages in publications.
Type 'demo()' for some demos, 'help()' for on-line help, or
'help.start()' for an HTML browser interface to help.
Type 'q()' to quit R.
> library(EcoHydRology)
Loading required package: operators
Attaching package: 'operators'
The following objects are masked from 'package:base':
options, strrep
Loading required package: topmodel
Loading required package: DEoptim
DEoptim package
Differential Evolution algorithm in R
Authors: D. Ardia, K. Mullen, B. Peterson and J. Ulrich
Loading required package: XML
> png(filename="/home/ddbj/snapshot/RGM3/R_CC/result/EcoHydRology/Lumped_VSA_model.Rd_%03d_medium.png", width=480, height=480)
> ### Name: Lumped_VSA_model
> ### Title: Lumped Variable Source Area (VSA) Watershed Model
> ### Aliases: Lumped_VSA_model
>
> ### ** Examples
>
> data(OwascoInlet)
> # First get rain and snow-melt input:
> rsm <- SnowMelt(Date=OwascoInlet$date, precip_mm=OwascoInlet$P_mm, Tmax_C=OwascoInlet$Tmax_C,
+ Tmin_C=OwascoInlet$Tmin_C, lat_deg=42.66)
Warning message:
In Solar(lat = lat, Jday = JDay[1], Tx = Tmax_C[1], Tn = Tmin_C[1], :
In Solar(): Input latitude units are not specified and assumed to be radians
> # Calculate streamflow based on watershed characteristics:
> Results <- Lumped_VSA_model(dateSeries = OwascoInlet$date, P = rsm$Rain_mm+rsm$SnowMelt_mm,
+ Tmax=OwascoInlet$Tmax_C, Tmin = OwascoInlet$Tmin_C, latitudeDegrees=42.66, Tp = 5.8, Depth = 2010,
+ SATper = 0.27, AWCper = 0.13, StartCond = "wet")
> # View results:
> hydrograph(streamflow=ConvertFlowUnits(cms=OwascoInlet$Streamflow_m3s, WA=106, AREAunits="mi2"),
+ timeSeries=OwascoInlet$date, streamflow2=Results$modeled_flow, precip=rsm$Rain_mm+rsm$SnowMelt_mm)
>
>
>
>
>
> dev.off()
null device
1
>