Hydrologic Modeling Using HEC-HMS: (3/9) - GIS pre-processing

[@sweetmemories4448]

Sir, you are doing a great service by answering the questions of most of the viewers. God bless you.

[@CLARISSEXOXO]

I am working with a similar tutorial from HEC-HMS for Salsipuedes Creek. I am following the exact same steps in the tutorial, but when I try to do any pre-processing, nothing happens, no layers are added. Have you heard of a similar issue?

[@hydrologyvideos8253]

make sure your data/dem is projected in the right coordinate system

[@muhammadzeeshan1752]

Sir I have my output location coordinates shapefile. Please help me how I can import it in HEC HMS

[@khadizatulkobranahin3877]

Hi, my HEC-HMS is computing flow accumulation for more than 3 hours now, it's still loading. I can't progress. I am using ASTER DEM (12.5m) and it shows the elevation in negative value. it is HEC-HMS 4.9. Can I get some help?

[@hydrologyvideos8253]

Make sure your data are correctly projected and your machine is able to handle the size of your data. If your projection is correct, try converting your DEM to 30m. That should reduce the computational burden.

[@khadizatulkobranahin3877]

@@hydrologyvideos8253 Many thanks. This problem has been solved. But the identified streamlines in my project doesn't match the terrain. Is there any way to edit them?

[@hydrologyvideos8253]

@@khadizatulkobranahin3877 the newer version of HEC-HMS has the option of reconditioning (burning of streams) which may solve this problem.

[@khadizatulkobranahin3877]

@@hydrologyvideos8253 Many Many thanks sir.

[@kaytang6507]

I ran it on my own DEM, but it resulted in hundreds of super small sub-basins after taking an hour to compute. I guess the software is getting way too precise. Is there a method to limit the number of sub-basin and set a minimum area for them.

[@hydrologyvideos8253]

what threshold area are you using to delineate streams? increase that area and number of sub-basins will decrease. try using 5% of your total watershed area for delineating streams

[@kaytang6507]

@@hydrologyvideos8253 Are you refering to the number we enter for "Identify Stream" ?

[@hydrologyvideos8253]

@@kaytang6507 yes

[@中國華仔]

sir, really appreciate your work, I pressed preprocess sinks and nothing happened, no mew layers added, do you know what went wrong? thanks

[@Jithakr]

While doing preprocess drainage it takes long time 😢 i did not get the results

[@nuruladhazahrahahmadfitri7707]

hi! mine was same as yours. may i know if u have solved this problem?

[@biembamwangala6175]

Yes, it takes long if your Dem is big, mine took about 11hrs, but managed to get the drainage

[@marufmuntasir284]

Thank you for the great videos! I was wondering where can I find your Arc Hydro tutorials. I went throught the playlist but nothing found related to Arc Hydro.

[@hydrologyvideos8253]

web.ics.purdue.edu/~vmerwade/tutorial.html

[@valteralbino362]

Great stuf, thanks a lot! I'm using HMS 4.9 and can't display the DEM nor do simple GIS things like terrain reconditioning. My reference system is OK (project in program settings and terrain) and since I'm outside USA, the regional settings are in english (USA), in my Windows10 x64 [with framework 4.8]. What could it be?

[@hydrologyvideos8253]

recreate or save your DEM again as TIFF. Open a new project and try again. I cannot think of anything else assuming that the program (HEC-HMS) was installed without any issues, or try installing version 4.8.

[@jibreelahmad1682]

Greetings sir, thankyou for your great video. How do you go about it suppose you want a specific point to be your outlet. assume you have the coordinates

[@hydrologyvideos8253]

You can create a point using the coordinates (in a GIS software0, and then add that point in hec-hms. Hope this helps!

[@KilasBerpikir]

Hello sir, could you share input data again? because link box can't open. thank you for the videos. It help me to understanding hec hms as beginner.

[@rabsranjit2321]

Thanks for the video. I have trouble while Preprocessing the sink. The whole catchment area gets the sink and hence there's problem in flow direction and accumulation. Any idea on how to solve it?

[@hydrologyvideos8253]

something may be wrong with your DEM. i cannot think of anything else.

[@alfred2011ful]

Good day sir, I need assistance on how to generate the CNgrid.tif use to derive the curve number in your HEC-HMS lecture series. I understand how you got the clipped cedar.tif file, my problem is how you got the CNgrid.tif. Thank you

[@hydrologyvideos8253]

look at this tutorial on how to create CN grid. you will need soil and landuse data: web.ics.purdue.edu/~vmerwade/education/qcngrid.pdf

[@andyharvielmawblei2671]

When delineating it says "cannot delineate because the breakpoints did not intersect the stream network" ...what could be the problem

[@hydrologyvideos8253]

Make sure you zoom-in as much as possible so you create the breakpoint on the stream

[@misspit2785]

@@hydrologyvideos8253 Amazing videos! I am facing the same problem no matter how much i zoom in!!

[@hydrologyvideos8253]

@@misspit2785 are you using your own dataset? sometimes issues with projection can cause this problem.

[@muhammadzeeshan1752]

Sir I have my output coordinates shapefile. Please help me how I can import it in HEC HMS

[@hebertlandu8195]

Thanks a lot for this great course. I enjoy watching and it’s very helpful for me. But I have a question : why do you put 25km as the area to define streams ?

[@hydrologyvideos8253]

The number that you use to define streams is little subjective. Many people use some percentage of their total watershed area (e.g., 1%, 5% etc) to define the stream network. In this case 25 km2 comes to around 3.5%. Lower number will give you more streams and higher number will give you less streams. It just depends on how detailed you want your discretization to be.

[@hebertlandu8195]

@@hydrologyvideos8253 thank you 🙏🏿.

[@gabrieldube9881]

Very helpful, thank you. Is there a reason you didn't automatically assign junctions? I've read the manuals, but I can't tell whether junctions at stream confluences are necessary for accurate computation of flow or not.

[@hydrologyvideos8253]

Junctions get created automatically where needed.

[@hamidehkazemi5458]

Thanks a lot for the awesome training. I am following the steps based on the video series. But I am stuck in catchment delineation. The software freezes after starting "delineate elements". Would you please be able to advise me on that? The catchment is very small so the complexity shouldn't be a problem. Cheers

[@hydrologyvideos8253]

I am assuming you are using your own dataset to delineate the sub-basins. Make sure your data are projected with proper coordinate system assigned. I cannot think of anything else.

[@hamidehkazemi5458]

@@hydrologyvideos8253 Perfect :). Thanks. The problem was with projection

[@srikanthvundavalli2890]

sir how can we get that input data file. we didn't get access to get that zip file

[@hydrologyvideos8253]

you can find the data here: web.ics.purdue.edu/~vmerwade/data/

[@rishaqgroup6588]

thanks for your video sir, but i want to teel about why my laptop can't run when drainage ? i was waited severy time . please help me thank you

[@hydrologyvideos8253]

I cannot help with your computer issues!

[@sumaiyayasmin1151]

why did you use a 25 square km stream area?

[@hydrologyvideos8253]

that area is about 4% of the drainage area. You can pick any percentage that you want depending on how many sub-basins you want to have in your discretization.

[@samsahb9428]

hello: Thanks a lot for great presentation. I am unable to download the data, it says its unavailable. Can you please share it

[@hydrologyvideos8253]

try this link: web.ics.purdue.edu/~vmerwade/data/

[@ogbolevictor5333]

The video is very helpful

[@nusratnasrinkhan1218]

Can you please provide the data? I can not find it in the tutorial.

[@hydrologyvideos8253]

The description is modified to include the link to the tutorial.

[@hydrologyvideos8253]

Here is the link to the dataset: ftp://ftp.ecn.purdue.edu/vmerwade/download/data/hms44.zip

[@paolaandreariverarangel5559]

​@@hydrologyvideos8253 Hi! I haven't been able to download the dataset. The link opens the Purdue University page but it says Error: 404 - Not Found. Thanks in advance.

[@hydrologyvideos8253]

@@paolaandreariverarangel5559 Please use windows explorer and past the ftp link without the actual zip file. You should then be able to see the folder and copy the dataset.

[@emperorgaming5885]

@@hydrologyvideos8253 still cant be able to download it on windows 11. can anyone else (who already have the data) will share drive link for the same?

[@itsmejr6165]

sir, really appreciate your work, I pressed preprocess sinks and nothing happened, no mew layers added, do you know what went wrong? thanks

[@amruthakb3807]

same for me ...i use 4.11 version

[@itsmejr6165]

@@amruthakb3807 same version.