Calculate a Unit Hydrograph from a DEM in QGIS

[@Desire_to_achievement]

This is one of the hardest tutorial i think you had made. Thanks a lot❤

[@aarizahmed4514]

Very informative video that will help to understand the hydrological characteristics of watershed

[@AbidAli-bv2gl]

Another Excellent video sir

[@НатальяСосонная-ц5м]

A big thank you for your work

[@robbieseehund7774]

Thank you very much for this great tutorial. I have a question regarding the tool "RasterDataPlotting" - I'm using QGIS 3.34 LRT and cannot find it in the PlugIn section. On the QGIS-PlugIn-Website it states "This plugin is deprecated!". Is there another more up-to-date plug-in that offers similar functions? Many thanks from Germany🙂

[@HansvanderKwast]

Hi. I don't know this plugin. Maybe you can describe what it does and I can see if there's an equivalent?

[@UdayKumar-ru1vz]

Sir, I have tried to install PCRaster tools in Qgis as explained in your other video session but still, I am getting an error ( PCRaster is not installed)

[@HansvanderKwast]

Then you're probably using an OSGeo4W installer that doesn't correspond with the QGIS you launch. Click right on QGIS Desktop in the Start menu and go to the folder. Run the OSGeo4W installer from that folder. The you're sure it's the correct one.

[@nikhilvinay6794]

Super tutorial sir I am exited to do this can u please send any documentation on this

[@HansvanderKwast]

Link to the method is in the description of the video.

[@krowf1161]

Great Tutorial Sir. But, What would be the units of the axes of the resulting hydrograph? Thanks for sharing with us!

[@HansvanderKwast]

Y axis: Discharge at outlet per unit of excess rainfall (sq. meters per second). X-axis: Time (seconds)

[@Pittyplaetsch]

Thank you for your amazing tutorials. PCRaster is indeed a great tool. I have one question: The documentation to ldddist is not mentioning any unit of the output and I can't find the theoretical background for it. Are you sure the output is in seconds? Would it also be possible to use mannings n values to incorporate land use for the weights raster? Thanks again for your great videos!

[@HansvanderKwast]

Ldddist calculates the distance over the flow direction. Distance units are in map units.

[@Pittyplaetsch]

@@HansvanderKwast thanks for your quick reply! In this video you save the results of ldddist as "traveltime" and mention at min 8:45 that it is in seconds, or did I get something wrong? Is it because of the Weight raster which has the unit T/L ?

[@preethyps1931]

Can this be done in ArcMap

[@onkarchothe6897]

sir, I have created all layers but column file to PCraster map not created that showing error . how to create outlet point?

[@HansvanderKwast]

Make sure your folder and file name has no spaces. Best to save your files on your local hard drive in a dedicated folder with a short name.

[@RP-qu9wk]

Great!! is it possible to export IUH in .CSV file?

[@HansvanderKwast]

Unfortunately, the plugin doesn't give that option. You'll have to export the rasters to separate CSV files using the gdal2xyz tool from the Processing Toolbox. Then in a spreadsheet programme you can merge them into 1 CSV. I'm planning to implement the PCRaster map2col tool that can create a CSV for values from multiple rasters. I hope to add it soon.

[@onkarchothe6897]

Sir, I got problem in create the layer outlet. Copy past coordinates in this form (386428.19,1839087.75,1). i have create notepad txt file. but when i attach the txt file, ldd file to Column file to PCRaster Map that showing me error. please help me to create outlet layer. is there any other method to create outlet layer?

[@onkarchothe6897]

Sir , can you please help me in that?.

[@onkarchothe6897]

I have try that 20-25 times.

[@HansvanderKwast]

It has most likely to do with your file/folder names. But if you can't solve that you follow these steps: 1. Go to the OSGeo4W shell. An easy way is to go to the Browser panel, click right on the folder where your data is and choose Open in terminal... 2. In the terminal type: col2map -N yourcsvfilename.txt outlet.map --clone yourlddmap.map 3. Click enter and if your files exist and are correct it will produce the desired output. It will also display issues on the screen.

[@onkarchothe6897]

@@HansvanderKwast thank you so much, sir. I will try this.

[@elisaurysuarez5927]

Great!!!

[@PerteTotale]

You were dividing water flow velocities into classes. Why? Perhaps following a script, perhaps that which you mentioned. That causes jagged curves. I learned that even using different time tempi 15m/60minute of sidestream outflows cause the same effect. And a unit hdg is not the sole answer to a very extreme diversing flow. Soil use diferentiation, soil wetness saturation, and so many things... I studied the Ahrtal flood disaster since it happened, got some eyeopening results, and I'm looking for a job into this area.

[@FormikFilms]

Hi there, I am currently doing my MSc thesis on the floods in the Ahr, Vesdre, etc. What are some of the most interesting results that you have found so far? My QGIS skills are not yet that great, so I have not yet been able to find any significant results.

[@PerteTotale]

@@FormikFilms I started work on Ahrtal at 15/07/21, as I had seen the weather forcast the day before... and I'm still working on it. The work is like a PhD now. Hans! First: I compared this flood with older flood info in that Ahr valley. Second: next fundament is (know your) history: most is written German, some in Eng. I can read D,F,E,G,and I. Third: I only started GIS-help in Oct 2021. So I think GIS is not ess., why use gis on shi te data? When you have good data analytic skills and can use many software pkgs, you can sieve it thru. 4th: I don't know what youre formation is, a geographer or a geologist, some engineer, human sciences... It matters much for your view/starting point and direction. 5th: getting good data on a golden plate: it is not there (for Ahr), too short timeseries on official websites, mostly it's dated, too coarse, nons, errors, data based on wrong calculations, or completely wrong forecasts... 6th: so that can be my cheapest hint: most official data is nuts ps, I did not get a notification of your reply here, so if I dont reply soon, it is not my fault, I try to remmeber this post

[@ΚωνσταντίνοςΠρούντζος]

could use pls link an email so i can send you a chart calculating the U.H. and the U.H. for a specific time

[@ethiogeotech4695]

hydraulics.lecture.ub.ac.id/files/2012/10/UNIT-HYDROGRAPH-DERIVED-FROM-A-SPATIALLY-DISTRIBUTED-VELOCITY-FIELD.pdf