Hi Shane. I'm happy to report that I've modeled overland water flow with r.watershed for over a quarter million acres, consisting of several large project sites, at 1 meter DEM resolution. The data source was LiDAR points to make the DEMs.
At this resolution, it becomes necessary to add culverts, or other artificial flow control features, to achieve water flowing through a road. Otherwise, water is routed along roads until a lowest point is reached for crossing. I also use r.terraflow outputs as ancillary data to help drop in culvert locations and help provide guidance in problem areas. My geographic area is central Florida, which is very flat and full of topographic depressions known as wetlands. These depressions interrupt the stream network continuity in reality, but r.watershed does a fantastic job making a continuous drainage network model, especially in these difficult areas. Happy Modeling! Mark On Tue, Dec 5, 2017, 3:49 PM Shane Carey <[email protected]> wrote: > Hi, > > I am trying to extract river network from a 5m DEM with some success using > r.watershed. Has anyone tested this algorithm on high resolution LiDAR data > for example - 1meter DTM and what kind of results have they obtained? > > Thanks > > -- > Le gach dea ghui, > *Shane Carey* > *GIS and Data Solutions Consultant* > _______________________________________________ > grass-user mailing list > [email protected] > https://lists.osgeo.org/mailman/listinfo/grass-user
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