r.carve
r.carve - Takes vector stream data, transforms it to raster and subtracts depth from the output DEM.
Raster (r.*)
ParameterRaster|rast|Elevation|False
ParameterVector|vect|Vector layer containing stream(s)|1|False
ParameterNumber|width|Stream width (in meters). Default is raster cell width|None|None|1
ParameterNumber|depth|Additional stream depth (in meters)|None|None|1
ParameterBoolean|-n|No flat areas allowed in flow direction|False
OutputRaster|output|Modified elevation
OutputVector|points|Adjusted stream points