How did you add culverts?! Such a great question and I also wonder how you did. Short ago I knew about Itzï and its ability to do it with SWMM http://itzi.readthedocs.io/en/latest/tutorial.html#culvert-modelling. Looking forward to testing it -- Marco
2017-12-06 9:24 GMT+01:00 Shane Carey <[email protected]>: > Hi Mark, > > Thanks for your reply! Sounds great. > How did you add culverts or other artificial flow control features to > achieve water flowing through roads? > > I have a rivers layer and I compared it the streams I've obtained from > r.watershed and r.watershed appears to not match these streams (which were > accurately digitised) and I was wondering if I had a better resolution DTM > would it solve this problem? > > Also, why is sink filling needed for terraflow and not watershed? > > Thanks for your help :-) > > On Máirt 5 Noll 2017 at 23:43, Mark Seibel <[email protected]> wrote: > >> 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 >> >> -- > 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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