In inrae/airGRiwrm: 'airGR' Integrated Water Resource Management

knitr::opts_chunk$set(
  collapse = TRUE,
  comment = "#>",
  fig.width = 6,
  fig.asp = 0.68,
  out.width = "70%",
  fig.align = "center"
)

library(airGRiwrm)

Presentation of the study case

The calibration results shown in vignette 'V02_Calibration_SD_model' for the flows simulated on the Avon at Evesham (Gauging station '54002') and on the Severn at Buildwas (Gauging station '54095') are not fully satisfactory, especially regarding low flows. These upper basins are actually heavily influenced by impoundments and inter-basin transfers [@higgsHydrologicalChangesRiver1988].

So, to cope with these influences, in this vignette, we use direct injection of observed influenced flows instead of modeling natural flow with an hydrological model.

We use observation on the Avon at Evesham (Gauging station '54002') and we choose to do the same on the Severn at Bewdley (Gauging station '54001') as if the observed flow at these locations would be the observed release of a dam.

Please note that the flow on the Severn at Buildwas (Gauging station '54095') is still simulated but its flows is no longer routed to downstream.

Conversion of a gauging station into a release spot

Modification of the GRiwrm object

The creation of the GRiwrm object is detailed in the vignette "V01_Structure_SD_model" of the package. The following code chunk resumes all the necessary steps:

data(Severn)
nodes <- Severn$BasinsInfo[, c("gauge_id", "downstream_id", "distance_downstream", "area")]
nodes$model <- "RunModel_GR4J"

To notify the SD model that the provided flows on a node should be directly used instead of an hydrological model, one only needs to declare its model as NA:

nodes$model[nodes$gauge_id == "54002"] <- NA
nodes$model[nodes$gauge_id == "54001"] <- NA
griwrmV03 <- CreateGRiwrm(nodes, list(id = "gauge_id", down = "downstream_id", length = "distance_downstream"))
griwrmV03

Here, we keep the area of this basin which means that the discharge will be provided in mm per time step. If the discharge is provided in m³/s, then the area should be set to NA and downstream basin areas should be modified subsequently.

The diagram of the network structure is represented below with:

• in blue, the upstream nodes with a GR4J model
• in green, the intermediate nodes with an SD (GR4J + LAG) model
• in red, the node with direct flow injection (no hydrological model)

plot(griwrmV03)

Generation of the GRiwrmInputsModel object

The formatting of the input data is described in the vignette "V01_Structure_SD_model". The following code chunk resumes this formatting procedure:

BasinsObs <- Severn$BasinsObs
DatesR <- BasinsObs[[1]]$DatesR
PrecipTot <- cbind(sapply(BasinsObs, function(x) {x$precipitation}))
PotEvapTot <- cbind(sapply(BasinsObs, function(x) {x$peti}))
Precip <- ConvertMeteoSD(griwrmV03, PrecipTot)
PotEvap <- ConvertMeteoSD(griwrmV03, PotEvapTot)
Qobs <- cbind(sapply(BasinsObs, function(x) {x$discharge_spec}))

This time, we need to provide observed flows as inputs for the nodes '54002' and '54095':

QobsInputs <- Qobs[, c("54001", "54002")]

Then, the GRiwrmInputsModel object can be generated taking into account the new GRiwrm object:

IM_OL <- CreateInputsModel(griwrmV03, DatesR, Precip, PotEvap, QobsInputs)

Calibration of the new model

Calibration options is detailed in vignette "V02_Calibration_SD_model". We also apply a parameter regularization here but only where an upstream simulated catchment is available.

The following code chunk resumes this procedure:

IndPeriod_Run <- seq(
  which(DatesR == (DatesR[1] + 365*24*60*60)), # Set aside warm-up period
  length(DatesR) # Until the end of the time series
)
IndPeriod_WarmUp = seq(1,IndPeriod_Run[1]-1)
RunOptions <- CreateRunOptions(IM_OL,
                               IndPeriod_WarmUp = IndPeriod_WarmUp,
                               IndPeriod_Run = IndPeriod_Run)
InputsCrit <- CreateInputsCrit(IM_OL,
                               FUN_CRIT = ErrorCrit_KGE2,
                               RunOptions = RunOptions, Obs = Qobs[IndPeriod_Run,],
                               AprioriIds = c("54057" = "54032", "54032" = "54029"),
                               transfo = "sqrt", k = 0.15
)
CalibOptions <- CreateCalibOptions(IM_OL)

The airGR calibration process is applied on each hydrological node of the GRiwrm network from upstream nodes to downstream nodes.

OC_OL <- suppressWarnings(
  Calibration(IM_OL, RunOptions, InputsCrit, CalibOptions))
ParamV03 <- sapply(griwrmV03$id, function(x) {OC_OL[[x]]$Param})

Run of the model with this newly calibrated parameters

OM_OL <- RunModel(
  IM_OL,
  RunOptions = RunOptions,
  Param = ParamV03
)

Plotting of the results

As can be seen below, compared to results of vignette "V02_Calibration_SD_model", the use of measured flows on upstream influenced basins largely improves the model performance at downstream stations (better low-flow simulations).

plot(OM_OL, Qobs = Qobs[IndPeriod_Run, ], which = "Regime")

The resulting flows of each node in m³/s are directly available and can be plotted with these commands:

Qm3s <- attr(OM_OL, "Qm3s")
plot(Qm3s[1:150, ])

References

inrae/airGRiwrm documentation built on Sept. 27, 2024, 6:08 p.m.