Given an undeveloped site ( with surveyor points, of course), can you tell where are the streamlines, and what catchment ( watershed) is going into those streamlines?
As a good engineer, when given a site, one must develop some intuitive feeling on where the streamlines are located, and which parts of the sites contribute to which streamlines. Fortunately in an area where computer is doing most of the traditional manual work, one can develop powerful algorithms to delineate streamlines and catchments, with good accuracy.
The have the accurate streamline and catchment delineation is essential to compute the Pre-development inflow-hydrograph. More specifically, it allows the engineer to compute the length of the flow path, \(L\) and the slope of the flow path, \(S\) more accurately.
In MiTS 2.1, we utilize TauDEM— the de facto software for watershed analysis to give user a feel where the streamlines and catchments are located for their sites. The Flow Direction algorithm that we use is D8, as this is the most robust method so far.
This is the watershed analysis result. Note that the thicker the line is, the bigger the stream is, consistent with our intuition. Also note that each color denotes one catchment. There is no special meaning in the color, we only use it to group all the DEM cells that contribute to the same drain.
The full project can be downloaded from here