r.watershed: multiple outlets points at once for watershed delineation

[hzambran]

I consider the 'r.watershed' a very efficient function for watershed delineation, in particular after the changes introduced in Grass7 (​http://lists.osgeo.org/pipermail/grass-user/2012-April/064500.html). However, there is a feature that I'm missing in order to start using it as a replacement of similar functionality available in TauDem5 (​http://hydrology.usu.edu/taudem/taudem5.0/):

The possibility of providing, in addition to the DEM file, an optional shapefile with the known locations of the desired outlet point(s), in order to be able to define the watersheds not only by using a threshold for the upstream area, but also by using the location of all the outlet points present in the main study area.

It would be great if you could consider implementing such a feature for the official release of Grass7.

This feature should be able to:

-) move all the outlet points provided by the user to nearest cell belonging to the river network. -) apply the current 'r.watershed' to each one of the outlets points obtained in the previous step.

Thanks in advance for considering this.

Mauricio Zambrano-Bigiarini

PS, More info about how TauDem5 perform this on: ​http://hydrology.usu.edu/taudem/taudem5.0/TauDEM5DelineatingASingleWatershed.pdf

[mmetz]

Replying to hzambran:

[...] there is a feature that I'm missing in order to start using it as a replacement of similar functionality available in TauDem5 (​http://hydrology.usu.edu/taudem/taudem5.0/):

The possibility of providing, in addition to the DEM file, an optional shapefile with the known locations of the desired outlet point(s), in order to be able to define the watersheds not only by using a threshold for the upstream area, but also by using the location of all the outlet points present in the main study area.

It would be great if you could consider implementing such a feature for the official release of Grass7.

This feature should be able to:

-) move all the outlet points provided by the user to nearest cell belonging to the river network.

-) apply the current 'r.watershed' to each one of the outlets points obtained in the previous step.

The addon module r.stream.basins already defines the catchment areas for one or more outlets, using the output of r.watershed. You could then set a MASK for each catchment and do further processing with the r.stream.* modules. BTW, you can also use the output of TauDem (DEM + flow accumulation) as input for r.stream.extract and then continue with other r.stream.* modules.

Markus M