velocity | R Documentation |

Estimate streamflow velocity in average over the catchment.

velocity(hl, ...) ## Default S3 method: velocity(hl, lagtime, method = "loire2016", ...) ## S3 method for class 'units' velocity(hl, lagtime = NULL, method = "loire2016", ...) ## S3 method for class 'stars' velocity(hl, ...) ## S3 method for class 'transfR' velocity(hl, ...)

`hl` |
hydraulic length of class |

`...` |
further arguments passed to or from other methods |

`lagtime` |
lag time of the catchment. If no unit is provided, |

`method` |
character string describing the method to estimate the velocity. One of "loire2016" (default), "brittany2013" or "lagtime" (see details). |

Estimate the average streamflow velocity of the catchment from three different approaches. Method "lagtime" estimates the velocity from the ratio between the mean hydraulic length and the lag time of the catchment. Method "loire2016" estimates the velocity from a regression based on hydraulic length only:

*a \cdot hl^b*

where *a=4.38e-4* and *b=0.69* have been calibrated over the Loire river basin \insertCitedeLavenne2016transfR.
Method "brittany2013" used a similar regression calibrated for the French Brittany region where *a=8.59e-4*
and *b=0.61* \insertCitedeLavenne2013transfR.

A numeric value of class units, or if `hl`

is a transfR object,
the same transfR object incremented by the "uc" attribute.

deLavenne2013transfR

\insertRefdeLavenne2016transfR

data(Oudon) velocity(Oudon$hl[[1]], method = "loire2016") object <- as_transfr(st = Oudon$obs, hl = Oudon$hl) object <- velocity(object) object$uc

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