river {topmodel}

Identification of rivers in a digital elevation model

Description

This function identifies river headwater cells based on threshold values in a topographic index and accumulated area river (generated using topidx. Rivers are then traced downslope using a single flow algorithm.

Usage

  river(DEM,atb,area,res,thatb,tharea)

Arguments

DEM

A matrix representing a digital elevation model [m] with equally sized pixels and equal NS and EW resolution

atb

Matrix with topographic index values generated by topidx

area

Matrix with drainage area values generated by topidx

res

Resolution of the digital elevation model (m)

thatb

A topographic index threshold for headwater cells

tharea

A drainage threshold for headwater cells

Details

Cells that exceed thatb or tharea in the respective maps are identified as headwater cells. The routine then traces down rivers from these cells based on a D8 algorithm and calculates the distance towards the outlet. Outlets are recognized by sinks, map borders or excluded areas (NA). The subcatch function can be used to set areas outside the target catchment to NA.

Value

A matrix of the same size as DEM.

Author(s)

Wouter Buytaert, Imperial College London, based on an implementation from the Hydrology Group of Lancaster University

References

See https://github.com/ICHydro/topmodel for examples.

See Also

subcatch, topidx