HEC-HMS for HEC-RAS Users Part 3 of 4: Using boundary and flow path shape files in HEC-RAS models

[@melodictube11]

what if you don't merge the subbasins and the streams and work with them as separate units?

[@felipeteixeira8285]

Hello, thank's for the video. I couldn't see how the runoff parameters (CN, Clark R, etc) are defined at HEC-RAS. Diferently than HMS, where you define each parameter (initial loss, Clark parameters, etc), here at RAS I couldn't identify this step. The Curve Number or soil equivalent Manning, can be defined at RAS?

[@18billmullen]

I just had the same question. Precipitation is brought in but no mention of land cover or hydrologic soil groups or identifying the parameters you've discussed.

[@octaviocervantes4965]

You have to insert a Manning and CN number shapefile in Ras Mapper before doing the simulation, with land cover layer and infiltration layer.

[@umairrasool9580]

@@octaviocervantes4965 Hi, i am learning HEC RAS, could you please guide me how insert a Manning and CN number in shapefile. Thanks

[@octaviocervantes4965]

@@umairrasool9580 hello Umair, first you have to make a shapefile in ArcGis or Qgis with polygons depending on the manning coefficients you have in the model. Subsequently, you have to introduce this shapefile with in RAS Mapper in the option Map layer, create a new Ras layer and land cover layer. In this option you load the shapefile and create the layer in the model.

[@umairrasool9580]

@@octaviocervantes4965 Thanks for your kind response. i am still confused on "polygons depending on the manning coefficients you have in the model". Could you please elaborate little more. Thanks