https://communities.bentley.com/products/road___site_design/f/geopak-inroads-mx-openroads-forum/201589/ir-ord---calculating-drainage-areasWe tried loading a DEM based DTM into InRoads to compute contributing areas using the Display Source Areas tool. Unfortunately, the point based surface does not really lend itself to this tool. Too often, the triangulation algorithm forms faces that cuten-USTelligent Community 12https://communities.bentley.com/thread/603704?ContentTypeID=1Thu, 13 Aug 2020 06:03:00 GMT6dad98f5-dbc9-4c4d-a9ba-e9da8dc6aa8e:f4bef3de-9175-47a5-92dc-b3fe28da9f0fErdem Atilir<p>I think it is better to use Global Mapper instead. You can&nbsp;export catchments areas and flow lines for the specific point of interest. I have tried many ways&nbsp;specifically in open roads but couldn&#39;t succeeded. It is relatively inexpensive application. I hope it helps.</p><div style="clear:both;"></div>