Delineating Urban Watersheds

[KateEkhator74]

Hello all,

Just wondering if I need to burn stormwater inlets into the DEM in addition to burning the pipeline network when delineating an urban watershed. I have accessed materials that referenced burning pipeline networks into DEM before running the different geo-processing tools to complete delineation. I was able to burn the pipeline network, but I recently came across some new materials referring inlets to sinks that should be incorporated when delineating urban watersheds. But these materials did not give clear description of how to accomplish this. I am also not clear on how I am required to burn both features (points and lines) into the same DEM. Please I would appreciate any hints on how to carry out the process of burning both (points and lines features) in to the raster.

Thank you.

[DanPatterson]

1. first thought would be to buffer the points and lines by a small amount so that the outlets meet the lines (perhaps 2x the desired cell size
2. now that they are both polygon files, merge them and use the result to locate the areas for burning

[KateEkhator74]

Thanks for responding. But I am not clear on how to carry out these steps you have mentioned, I have completed burning of the sewer lines into the DEM by reducing the pixel values for areas where these lines fall using a raster calculator. This method tricks the software into thinking that the sewer line are surface channels were flow will accumulate. My question is do I still need to consider the inlets by burning them into the DEM with the sewer lines already burned into it? Or the DEM with only the burned sewer lines is sufficient to generate the urban watershed. And if I needed to burn the inlets into the DEM, is it okay to lower the pixel values again for the same DEM at the inlet locations. I hope this gives more information?

Thank you.

Kate.