topic Re: Watershed Delineation using Hec Geo HMS in Water Resources Questions

Watershed Delineation using Hec Geo HMS

AjayMore — Fri, 12 Jul 2013 15:57:10 GMT

Hello all,
I am trying to delineate watershed using HEC Geo HMS extension in Arc Map and watershed delineated is less than original extent and size of watershed. I loaded a polygon file of my actual watershed to the watershed generated by Geo HMS, but after that I am not getting how to proceed with Geo HMS to create the required data frame.

Any help will be highly appreciated.

Thanks very much.

Ajay

Re: Watershed Delineation using Hec Geo HMS

MattHamilton — Fri, 12 Jul 2013 16:06:22 GMT

Hey Ajay,

Have you taken a look at the HEC-GeoHMS User's Manual for your specific version of ArcGIS? By the way, which version are you running? A tad more information and I may be able to help.

Re: Watershed Delineation using Hec Geo HMS

AjayMore — Fri, 12 Jul 2013 16:15:20 GMT

Hello mhamilton,
I am using 10.1. Also I am using Dr. Merwade's tutorial 'Terrain Processing and HMS model development using Geo HMS. I am basically having problems in the 'Note' of this tutorial on page 8. I am attaching below some snaps that might help you understand my problem in depth. If I use the watershed generated by Geo Hms things work fine but I am stuck on how to proceed after I upload my data into ProjectArea_H (as is shows in attacthed Figures)

Thanks a lot.

Ajay[ATTACH=CONFIG]25898[/ATTACH][ATTACH=CONFIG]25899[/ATTACH][ATTACH=CONFIG]25900[/ATTACH]

Re: Watershed Delineation using Hec Geo HMS

MattHamilton — Fri, 12 Jul 2013 16:52:32 GMT

Hi Ajay,

Check out chapter 7 in the user's manual. Here is a link: http://www.hec.usace.army.mil/software/hec-geohms/documentation/HEC-GeoHMS_Users_Manual_10.1.pdf

Basically, you need to create the project, begin adding project points and this will start your data frame.

Does that help?

Re: Watershed Delineation using Hec Geo HMS

AjayMore — Fri, 12 Jul 2013 17:11:02 GMT

Hi,
I am able to create watershed using the default watershed delineated by Geo HMS, but that is not my extent of the watershed, my extent of watershed is more than that and so I have to upload data into ProjectArea feature class. After loading this data I am not getting how to proceed with Geo HMS.

Thanks

Ajay

Re: Watershed Delineation using Hec Geo HMS

MattHamilton — Fri, 12 Jul 2013 17:19:46 GMT

Hey there,

Have you tried submitting your issue directly through the HEC-GeoHMS site? Here is the direct link to do that: http://www.hec.usace.army.mil/software/hec-geohms/bug_report.aspx

I am at a loss. The only suggestion I can think of is more of a meandering in my mind. Maybe the layers that you didn't actually create in GeoHMS need to be amended or something. Like I said, I am at a loss. I'm sorry I couldn't be of any more help.

Would someone else on the forums like to take a crack at this problem?

Re: Watershed Delineation using Hec Geo HMS

AjayMore — Fri, 12 Jul 2013 17:21:46 GMT

Hi Hamilton,
Thanks a lot..may be this will help.

Ajay

Re: Watershed Delineation using Hec Geo HMS

MattHamilton — Fri, 12 Jul 2013 17:25:24 GMT

No problem Ajay. The more I think about it, and looking at the tutorial you are using, the more I think I am right you need to amend the data you didn't create in GeoHMS, ie. HydroID.

Re: Watershed Delineation using Hec Geo HMS

AjayMore — Fri, 12 Jul 2013 17:28:23 GMT

Hi,
I used the editor and made Hydro ID of Project area and Project point same, I am not sure if you are referring to this only.

Thanks

Ajay

Re: Watershed Delineation using Hec Geo HMS

MattHamilton — Fri, 12 Jul 2013 17:29:53 GMT

I was... interesting. Yea, I am at a loss.

Any other forumers want to give this problem a shot?

Re: Watershed Delineation using Hec Geo HMS

MarkBoucher — Fri, 19 Jul 2013 16:23:46 GMT

I looked closely at Ajay's image. In the upper right portion, there is a stream that goes outside of the watershed boundary. This is likely the problem. See the attached close up of the spot the creek leaves the boundary. If you modify your boundary to include the stream, things should get better. All your grid data (fdr, rawdem, str, strlnk, etc...) need to be inside the boundary also.

I once had a creek that went right up to the edge of a watershed. In the processing creek would end right near the boundary. I think it is because the burning streams lowered the DEM at the boundary and then the flow direction grid naturally choose that as the outlet. The solution was to use an "outer wall". This is likely what is needed here.

One problem could be with the "polygon file of [your] actual watershed"⁽¹⁾. In the hydrology geoprocessing, nothing is the "actual watershed". The DEM is a discrete grid. If you look close at the streams generated, they go from grid center to grid center. The watershed boundary's do the same. This does not follow the "actual" feature (stream or ridge). So, if you try to superimpose an "actual watershed" on the grid, you need to consider that the polygon you bring in may not line up just right with the DEM.

[ATTACH=CONFIG]26070[/ATTACH]

⁽¹⁾This assumes that I understand what your doing with the "actual watershed". Did you load your "actual watershed" just for comparisons, or did you load it to use it in the processing (Batch Watershed Delineation for Watersheds)?

Re: Watershed Delineation using Hec Geo HMS

MarkBoucher — Fri, 19 Jul 2013 16:26:33 GMT

An attached image instead of an imbedded one.

Re: Watershed Delineation using Hec Geo HMS

AjayMore — Sun, 28 Jul 2013 05:03:40 GMT

Hello,
After a lot of efforts and thanks to all you guys for helping me out, esp. Mark Boucher.
I am really thankful for your detailed reply and I apologize for replying so late.
The problem was the threshold of Agree DEM, since my threshold was high, stream network got disconnected and hence my watershed was only upto the point of disconnect. lowering threshold solved my problem.

Cheers !!!

Ajay