This resource includes the code (written in Python 3.6) and the documentation of a technique which is presented for adjusting the slopes of a Digital Elevation Model (DEM) derived drainage network where the slope is zero. The procedure uses the stream river network delineated from the grid-based DEM using Terrain analysis using Digital Elevation Models (TauDEM) software and re-compute the slopes considering the length and slope of all the upstream, downstream, and side entrance reaches. The results of this procedure is that all of the DEM-derived drainage network will have a positive (“downhill”) slope which are constrained to be greater than 0 m/m even when the elevation smoothing process produces equal upstream and downstream elevations on a flow line.