Before using any hydrologic algorithms, regardless of the algorithm provider, we need to make sure that the DEM is hydrologically corrected. This means that we need to ensure that it behaves like the natural landscape, where surface flow moves across the land and does not get trapped in pits or depressions, in the DEM.
To accomplish this, we are going to use the Fill Sinks (Wang & Liu) tool from SAGA on our new DEM file, as illustrated in this screenshot:
Now, go to Layer Properties of Filled DEM and, under the Symbology tab, go to Color ramp | Create New Color Ramp... and select Catalog: cpt-city, and click OK
