topic Re: Null Values in the table for the Catchment polygon in Water Resources Questions

Null Values in the table for the Catchment polygon

JasonKarr — Thu, 03 Mar 2011 21:18:14 GMT

I ran the Catchment Polygon Process and it was successfull. However, upon further investigation of the polygon table, the ArcHydroID and GridID fields were Null. Later on in my workflow, I came to the "Ajoint Catchment Process" and got this error:

"Error occurered while computer Adjoint Catchment! Invalid use of Null."

Any ideas how to fix this?

Jason

Re: Null Values in the table for the Catchment polygon

StacieWolny — Tue, 08 Mar 2011 02:48:44 GMT

Hi, Jason -

I wish I could help, but instead this is a Me Too post. After 8 hours of running Drainage Line, I finally got to Adjoint Catchment, got the same Null error and see the same Null values in the Catchment layer. Sigh.

Too bad, as I was trying ArcHydro 1.4 because 1.3 also failed in Adjoint Catchment, but didn't throw an error, just returned an empty shapefile. So tantalizingly close to actually generating watersheds.

Does anyone know of any other tools out there that will delineate multiple, often nested watersheds at a time accurately given a point outlet layer? ArcSWAT seems to merge the resulting basins together, so you don't get a separate one for each outlet if they're nested or adjacent. AGWA only lets you do one at a time, and since I'm trying (fruitlessly) to generate watersheds for all of the major dams in the world, I want to do them in batch.

~ Stacie

Re: Null Values in the table for the Catchment polygon

GregMauldin — Mon, 28 Mar 2011 17:29:43 GMT

Hi,

I'm not sure if this addresses your particular problem but I ran into something related. I went through the entire terrain evaluation process, sucessfully I thought until I got to the point of creating the geometric network. The network creation process failed on an invalid Grid-ID error, (don't recall the specific error message...it was different from the error message you saw, but...) Now to the point. After many hours of painstaking backtracking, I traced the problem to an area near the edge of the DEM where there was enough data for the system to delineate a drainage line but no catchment was created during the catchment phase, so the Grid-ID was not correctly populated, a problem which was further propogated as I moved through the Arc Hydro workflow. The problem steemed from the fact that I used a political boundary to clip my original DEM, which resulted in interterminate flow along the edge. I reclipped using a hydrologic boundary and everything worked swimmingly. Again, not sure this is applicable to your problem but I didn't know it was applicable to mine until I discovered it!

Good Luck!

Greg