Hydro - TI and Hydro methodology

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larsvankleef
Posts: 5
Joined: Fri Sep 02, 2016 8:36 am

Hydro - TI and Hydro methodology

Post by larsvankleef » Fri Oct 28, 2016 7:12 am

Hi,

I am using i-Tree hydro from Sweden and I have two questions.

Firstly, since I am not from the US I have to provide my own Topographic Index file(I am modeling a non-watershed area). I am wondering if there is a file that shows me how the file has to formatted. I have looked through the database which is used for projects inside the United States, but my file has to be .DAT and not a database.

My second question is about the Hydro methodology. I have searched for a file showing the assumptions and methods used in the model, but this file seems to be deleted. All the links to it on the website are dead links. Can this article be found anywhere else?

Best regards,
Lars
rcoville
i-Tree Team
Posts: 55
Joined: Fri May 08, 2015 9:29 am
Location: Syracuse, NY

Re: Hydro - TI and Hydro methodology

Post by rcoville » Fri Oct 28, 2016 11:56 am

Hi Lars,

A good place to start for international i-Tree Hydro users is our FAQ on Hydro's data requirements and international limitations: https://forums.itreetools.org/viewtopic.php?f=35&t=1257

You'll see there that we recommend you use a DEM file for elevation data. For a step-by-step description of how a DEM can be exported for use in i-Tree Hydro, go to step 15 of appendix 1 in the i-Tree Hydro User Manual v5.1.

That user manual can also be useful for understanding the Hydro methodology. For peer-reviewed, scientific papers on Hydro's methods, please see the first part of the i-Tree Hydro Resources section in the i-Tree Archives.

I notice in those Archives, the first paper from Wang & Endreny, 2008 is not loading. I'll try to get that corrected this afternoon. For now, you can view that paper on ResearchGate: https://www.researchgate.net/profile/Da ... 000000.pdf

Let me know if there are other dead links you found and I'll try to get that updated. Thanks for the notice about that, and sorry for any inconvenience.
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larsvankleef
Posts: 5
Joined: Fri Sep 02, 2016 8:36 am

Re: Hydro - TI and Hydro methodology

Post by larsvankleef » Mon Oct 31, 2016 4:29 am

Hi,

I have looked at the FAQ, but in the user manual I noticed it is recommended to use a Topographic Index when working with a non-watershed area. I have already made this and split all the values into 30 histogram bins, so I would only need to know how this data is formatted. I have no problem using a DEM though, if that also works.

The peer-reviewed article is indeed what I was looking for, thanks!

Kind regards,
Lars
rcoville
i-Tree Team
Posts: 55
Joined: Fri May 08, 2015 9:29 am
Location: Syracuse, NY

Re: Hydro - TI and Hydro methodology

Post by rcoville » Mon Oct 31, 2016 8:51 am

The recommendation to use Topographic Index files is intended for US states, counties, cities or other US Census places that we have pre-loaded data for. Otherwise, we expect it will be easier for users to work with DEM files than create their own TI files. I'll try to clarify that by updating our Hydro user manual.

Since you've already created a TI file, it may be easy to go ahead and use that. Below is the contents of a pre-loaded TI file for USGS stream gauge 01648000, saved in a file with the .dat extension. To get that file extension, simply open the ASCII (text) file in a text processor and save it with a .dat suffix.

Code: Select all

Washington, District of Columbia
30 1
6.1808517E-05     22.6
0     22.0137931034483
0     21.4275862068965
6.1808517E-05     20.8413793103448
0.00049446814     20.2551724137931
0.00049446814     19.6689655172414
0.00166883     19.0827586206897
0.0027195748     18.4965517241379
0.0022251066     17.9103448275862
0.0033994684     17.3241379310345
0.0026577662     16.7379310344828
0.0027195748     16.151724137931
0.0045120218     15.5655172413793
0.0061190432     14.9793103448276
0.0061808517     14.3931034482759
0.011434576     13.8068965517241
0.013845108     13.2206896551724
0.012547129     12.6344827586207
0.019655108     12.048275862069
0.025526918     11.4620689655172
0.024290747     10.8758620689655
0.036034366     10.2896551724138
0.045614686     9.70344827586207
0.057605538     9.11724137931034
0.10291118     8.53103448275862
0.15359417     7.9448275862069
0.1553248     7.35862068965517
0.21466098     6.77241379310345
0.083626924     6.18620689655172
0.01001298     5.6
If you can't get the TI file you made working, I recommend trying a DEM.
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