1. Introduction

The QGIS Processing Toolbox gives access to many useful GRASS algorithms.

In this tutorial we're going to use the GRASS tools to delineate the Rur river and its catchment.

After this tutorial you're able to:

  • create a hydrologically correct DEM by filling the sinks
  • calculate flow accumulation
  • delineate streams using a flow accumulation threshold
  • delineate a catchment of a specified outlet
The tutorial data is an SRTM 1-Arc Second DEM that has been clipped and reprojected to UTM Zone 32N/WGS-84.