Watershed Delineation Using LiDAR insted of DEM

[ClaireRose]

Hello Everyone, I'm new to ArcHydro and delineation. However, I've been assigned a project in which I need to take LiDAR data (I also have access to DEM and aerial photography) and I need to auto-delineate watershes.

I have just installed ArcHydro sucessfully (I'm using ArcGIS 10 in Windows 7) but I do not know where to start. Has anyone got any tips for delineation using LiDAR data? I can use the DEM and aerial if I need to, but I'm supposed to mainly use the LiDAR (of which I've never worked with before either!)

I've found some helpful tutorials using DEM, but can this be done using LiDAR?

Thanks so much for any guidance you can suggest.

-Cerose

[LornaMurison]

You need to use your LiDAR data to create a DEM which will presumably be of a higher resolution than the existing one you are referring to.  I'm not familiar with what LiDAR data look like in raw format.  The "Comprehensive Terrain Preprocessing Using ArcHydro Tools" document is quite useful though, for understanding how to get your DEM into a format appropriate for catchment delineation.

[ClaireRose]

Lady Jane, Thank you so much for your response. That looks to be very helpful, now that I know I just need to convert the LiDAR to DEM, I feel much better about this project. Your help is much-appreciated!

[DuncanHornby]

Claire,

Once you have converted your RAW lidar data into a DEM you'll need to fill in sinks before you create the flow accumulation and flow direction grids. I don't have ArcHydro currently installed but I remember it has a fairly comprehensive Help document to guide you. For a high level step by step guide of how to generate watersheds have a look at this section of the ESRI help.

Duncan