diff --git a/DESCRIPTION b/DESCRIPTION
index 5f014f72277a964380628787db60314355eb381e..b41a249601cb24568db7bb238e7900551a884073 100644
--- a/DESCRIPTION
+++ b/DESCRIPTION
@@ -1,7 +1,7 @@
 Package: airGR
 Type: Package
 Title: Suite of GR Hydrological Models for Precipitation-Runoff Modelling
-Version: 1.6.3.1
+Version: 1.6.3.2
 Date: 2020-10-05
 Authors@R: c(
   person("Laurent", "Coron", role = c("aut", "trl"), comment = c(ORCID = "0000-0002-1503-6204")),
diff --git a/NAMESPACE b/NAMESPACE
index 858dd29341805d13d3e204cccbaf6f19370498a3..2842ced5516139441e6696479699d690529ebd69 100644
--- a/NAMESPACE
+++ b/NAMESPACE
@@ -45,6 +45,7 @@ export(RunModel_GR5H)
 export(RunModel_GR4J)
 export(RunModel_GR5J)
 export(RunModel_GR6J)
+export(RunModel_LAG)
 export(SeriesAggreg)
 export(TransfoParam)
 export(TransfoParam_CemaNeige)
diff --git a/NEWS.md b/NEWS.md
index 842f8784a68a30da78cc2dea2d64569826215061..460eee0eabae7be8cafc4cb423bec5639f8c6d72 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -1,10 +1,12 @@
 ## Release History of the airGR Package
 
-### 1.6.3.1 Release Notes (2020-10-05)
+### 1.6.3.2 Release Notes (2020-10-05)
 
 #### New features
 
 - Change order of parameters: LAG is now the first parameter instead of the last
+- Add argument checks in RunModel_LAG
+- Add Documentation page with example for RunModel_LAG
 
 ____________________________________________________________________________________
 
diff --git a/R/RunModel_LAG.R b/R/RunModel_LAG.R
index 3f06a19d776dbf0929094780eefc9de02965ece6..20d858fd90eeb02cff1f24d5b31346f439e8e731 100644
--- a/R/RunModel_LAG.R
+++ b/R/RunModel_LAG.R
@@ -1,5 +1,24 @@
 RunModel_LAG <- function(InputsModel,RunOptions,Param) {
 
+  NParam <- 1
+  
+  ##Arguments_check
+  if(inherits(InputsModel,"InputsModel")==FALSE){ stop("'InputsModel' must be of class 'InputsModel'") }  
+  if(inherits(InputsModel,"SD"      )==FALSE){ stop("'InputsModel' must be of class 'SD'") }  
+  if(inherits(RunOptions,"RunOptions"  )==FALSE){ stop("'RunOptions' must be of class 'RunOptions'") }
+  if(!is.vector(Param) | !is.numeric(Param)){ stop("'Param' must be a numeric vector") }
+  if(sum(!is.na(Param))!=NParam){ stop(paste("'Param' must be a vector of length",NParam,"and contain no NA")) }
+  
+  if(is.null(InputsModel$OutputsModel)) {
+    stop("'InputsModel' should contain an 'OutputsModel' key containing the output of the runoff of the downstream subcatchment")
+  }
+  if(is.null(InputsModel$OutputsModel$Qsim)) {
+    stop("'InputsModel$OutputsModel' should contain a key 'Qsim' containing the output of the runoff of the downstream subcatchment")
+  }
+  if(sum(!is.na(InputsModel$OutputsModel$Qsim)) != length(RunOptions$IndPeriod_Run)) {
+    stop("'InputsModel$OutputsModel$Qim' should have the same lenght as 'RunOptions$IndPeriod_Run' and contain no NA")
+  }
+  
   OutputsModel <- InputsModel$OutputsModel
   OutputsModel$QsimDown <- OutputsModel$Qsim
 
@@ -11,7 +30,7 @@ RunModel_LAG <- function(InputsModel,RunOptions,Param) {
   }
 
   # propagation time from upstream meshes to outlet
-  PT <- InputsModel$LengthHydro / Param[length(Param)] / TimeStep
+  PT <- InputsModel$LengthHydro / Param[1] / TimeStep
   HUTRANS <- rbind(1 - (PT - floor(PT)), PT - floor(PT))
 
   NbUpBasins <- length(InputsModel$LengthHydro)
diff --git a/man/CreateCalibOptions.Rd b/man/CreateCalibOptions.Rd
index d250d6e6c7890063b935bdcb25dbfa0ba8e9e84c..0d9bbf3f569cf45642f4877ca24c8f91dee05fbb 100644
--- a/man/CreateCalibOptions.Rd
+++ b/man/CreateCalibOptions.Rd
@@ -85,7 +85,7 @@ the package must create their own \code{CalibOptions} object accordingly. \cr
 If \code{IsHyst = FALSE}, the original CemaNeige version from Valéry et al. (2014) is used. \cr
 If \code{IsHyst = TRUE}, the CemaNeige version from Riboust et al. (2019) is used. Compared to the original version, this version of CemaNeige needs two more parameters and it includes a representation of the hysteretic relationship between the Snow Cover Area (SCA) and the Snow Water Equivalent (SWE) in the catchment. The hysteresis included in airGR is the Modified Linear hysteresis (LH*); it is represented on panel b) of Fig. 3 in Riboust et al. (2019). Riboust et al. (2019) advise to use the LH* version of CemaNeige with parameters calibrated using an objective function combining 75 \% of KGE calculated on discharge simulated from a rainfall-runoff model compared to observed discharge and 5 \% of KGE calculated on SCA on 5 CemaNeige elevation bands compared to satellite (e.g. MODIS) SCA (see Eq. (18), Table 3 and Fig. 6). Riboust et al. (2019)'s tests were realized with GR4J as the chosen rainfall-runoff model. \cr
 
-If \code{InputsModel} parameter has been created for using a semi-distributed (SD) lag model (See \code{\link{CreateInputsModel}}), the parameter \code{isSD} should be set to \code{TRUE}.
+If \code{InputsModel} parameter has been created for using a semi-distributed (SD) model (See \code{\link{CreateInputsModel}}), the parameter \code{isSD} should be set to \code{TRUE}.
 }
 
 
diff --git a/man/RunModel.Rd b/man/RunModel.Rd
index fab3924e9860056f0bf03c1b446f74bce2147a87..ceae5f1dc480d3ef4516b31ad145db9d769749a0 100644
--- a/man/RunModel.Rd
+++ b/man/RunModel.Rd
@@ -37,7 +37,7 @@ If \code{InputsModel} parameter has been created for using a semi-distributed (S
 }
 
 \details{
-If \code{InputsModel} parameter has been created for using a semi-distributed (SD) lag model (See \code{\link{CreateInputsModel}}), \code{Param} parameter should contain one extra last parameter corresponding to a constant lag parameter expressed as a velocity in m/s.
+If \code{InputsModel} parameter has been created for using a semi-distributed (SD) lag model (See \code{\link{CreateInputsModel}}), the first item of \code{Param} parameter should contain a constant lag parameter expressed as a velocity in m/s, parameters for the hydrological model are then shift one position to the right.
 }
 
 \examples{
diff --git a/man/RunModel_LAG.Rd b/man/RunModel_LAG.Rd
new file mode 100644
index 0000000000000000000000000000000000000000..fb3a500823e6603fbdb4166b2764544e4e2089f2
--- /dev/null
+++ b/man/RunModel_LAG.Rd
@@ -0,0 +1,98 @@
+\encoding{UTF-8}
+
+
+\name{RunModel_LAG}
+\alias{RunModel_LAG}
+
+
+\title{Run with the LAG model}
+
+
+\description{
+Function which performs a single run for the LAG model over the test period.
+}
+
+
+\usage{
+RunModel_LAG(InputsModel, RunOptions, Param)
+}
+
+
+\arguments{
+\item{InputsModel}{[object of class \emph{InputsModel}]  created with SD model inputs, see \code{\link{CreateInputsModel}} for details. The object should also contain a key \emph{OutputsModel}] of class \code{\link{CreateInputsModel}} coming from the simulation of the downstream subcatchement runoff.}
+
+\item{RunOptions}{[object of class \emph{RunOptions}] see \code{\link{CreateRunOptions}} for details}
+
+\item{Param}{[numeric] vector of 1 parameter
+  \tabular{ll}{
+    LAG \tab Mean flow velocity [m/s]
+  }}
+}
+
+
+\value{
+[list] see \code{\link{RunModel_GR4J}} or \code{\link{RunModel_CemaNeigeGR4J}} for details.
+
+The list value contains an extra item named \code{QsimDown} which is a copy of InputsModel\$OutputsModel\$Qsim, a numeric series of simulated discharge [mm/time step] related to the run-off contribution of the downstream sub-catchment.
+}
+
+
+\examples{
+library(airGR)
+
+## loading catchment data
+data(L0123001)
+
+## Simulating a reservoir
+# Withdrawing 1 m3/s with an instream flow of 1 m3/s
+Qupstream <- matrix(- unlist(lapply(BasinObs$Qls / 1000 - 1, function(x) {min(1, max(0,x, na.rm = TRUE))})), ncol = 1)
+# Except between July and November when releasing 3 m3/s
+month <- as.numeric(format(BasinObs$DatesR,"\%m"))
+Qupstream[month >= 7 & month <= 9] <- 3
+# Conversion in m3/day
+Qupstream <- Qupstream * 86400
+
+## The reservoir is not an upstream subcachment: its areas is NA
+BasinAreas <- c(NA, BasinInfo$BasinArea)
+
+## Delay time between the reservoir and the catchment outlet is 2 days and the distance is 150 km
+LenghtHydro <- 150
+LAG <- LenghtHydro / 2 / 86400 * 1000 # Conversion km/day -> m/s
+
+## preparation of the InputsModel object
+InputsModel <- CreateInputsModel(FUN_MOD = RunModel_GR4J, DatesR = BasinObs$DatesR,
+                                 Precip = BasinObs$P, PotEvap = BasinObs$E,
+                                 Qupstream = Qupstream, LengthHydro = LenghtHydro,
+                                 BasinAreas = BasinAreas)
+
+## run period selection
+Ind_Run <- seq(which(format(BasinObs$DatesR, format = "\%Y-\%m-\%d")=="1990-01-01"),
+               which(format(BasinObs$DatesR, format = "\%Y-\%m-\%d")=="1999-12-31"))
+
+## preparation of the RunOptions object
+RunOptions <- CreateRunOptions(FUN_MOD = RunModel_GR4J,
+                               InputsModel = InputsModel, IndPeriod_Run = Ind_Run)
+
+## simulation of dowstream subcatchment
+Param <- c(X1 = 257.238, X2 = 1.012, X3 = 88.235, X4 = 2.208)
+OutputsModelDown <- RunModel_GR4J(InputsModel = InputsModel,
+                                  RunOptions = RunOptions, Param = Param)
+
+InputsModel$OutputsModel <- OutputsModelDown
+OutputsModel <- RunModel_LAG(InputsModel = InputsModel,
+                             RunOptions = RunOptions, Param = LAG)
+
+## results preview of comparison between naturalised (observed) and influenced flow (simulated)
+plot(OutputsModel, Qobs = OutputsModel$QsimDown)
+}
+
+
+\author{
+Olivier Delaigue, David Dorchies
+}
+
+
+\seealso{
+\code{\link{RunModel}}, \code{\link{CreateInputsModel}}, \code{\link{CreateRunOptions}}.
+}
+
diff --git a/tests/testthat/test-RunModel_LAG.R b/tests/testthat/test-RunModel_LAG.R
index f46338dceae9e971ad0b0206f557df0c2d51b0ab..4dafb2f80a443a4a10509dde0851584ae5fc9ad2 100644
--- a/tests/testthat/test-RunModel_LAG.R
+++ b/tests/testthat/test-RunModel_LAG.R
@@ -54,6 +54,13 @@ RunOptions <- CreateRunOptions(FUN_MOD = RunModel_GR4J,
                                InputsModel = InputsModel,
                                IndPeriod_Run = Ind_Run)
 
+test_that("InputsModel parameter should contain an OutputsModel key", {
+  expect_error(
+    RunModel_LAG(InputsModel, RunOptions, 1), 
+    regexp = "'InputsModel' should contain an 'OutputsModel' key"
+  )
+})
+
 Param = c(257.237556, 1.012237, 88.234673, 2.207958) #  From vignettes/V01_get_started
 
 OutputsGR4JOnly <-
@@ -61,6 +68,33 @@ OutputsGR4JOnly <-
                 RunOptions = RunOptions,
                 Param = Param)
 
+test_that("InputsModel$OutputsModel should contain a Qsim key", {
+  InputsModel$OutputsModel <- OutputsGR4JOnly
+  InputsModel$OutputsModel$Qsim <- NULL
+  expect_error(
+    RunModel_LAG(InputsModel, RunOptions, 1), 
+    regexp = "should contain a key 'Qsim'"
+  )
+})
+
+test_that("'InputsModel$OutputsModel$Qim' should have the same lenght as 'RunOptions$IndPeriod_Run'", {
+  InputsModel$OutputsModel <- OutputsGR4JOnly
+  InputsModel$OutputsModel$Qsim <- c(InputsModel$OutputsModel$Qsim, 0)
+  expect_error(
+    RunModel_LAG(InputsModel, RunOptions, 1), 
+    regexp = "should have the same lenght as"
+  )
+})
+
+test_that("'InputsModel$OutputsModel$Qim' should contain no NA'", {
+  InputsModel$OutputsModel <- OutputsGR4JOnly
+  InputsModel$OutputsModel$Qsim[10] <- NA
+  expect_error(
+    RunModel_LAG(InputsModel, RunOptions, 1), 
+    regexp = "contain no NA"
+  )
+})
+
 test_that("Upstream basin with nil area should return same Qdown as GR4J alone", {
   UpstBasinArea = InputsModel$BasinAreas[1]
   InputsModel$BasinAreas[1] <- 0