In that case, you need to use the HECGeoRAS extension in arcgis which automatically generates cross section lines. Afterwards, it has to be imported to HEC-RAS environment.
When specifying the steady flow boundary conditions, you were using arbitrary values. I'm currently learning how to use the HEC-RAS software. If one wanted to practice using real data, how could I find this information?
Thank you, when i open geometry data it gives me the following error "error plotting geometric schematic". When i accept it, it saves me just one cross section. How can i solve it?
Thank you for reaching out. I am not aware of this problem. I hope that you have drawn all river center, banks, etc in correct order (ie from upstream to downstream) and the cross section to be created in left to right direction when looking downstream. Please also try saving the geometric file with a different name(no spaces). Share your findings with us afterwards.
Hello, thank you very much. This was helpful but I have a question please. How do we know what value to input as the flow data. I saw you give a couple of values but looks like random values. I will like to know why we need to input a flow data and how to get what values to input. Thank you
Thank you for your kind words of appreciation. The input value depends upon what sort of data is available with you. Usually but not necessarily, flow discharge is used as input. If you have access to other data then you can use them. Yes, the values I have entered are random; just for tutorial purpose. You can fetch flow hydrograph, if available for your desired study area, from authorized agencies of government related to hydrology or meteorology. Or you can use empirical formula to calculate it.
Thank you very much for your feedback. I watched a video where I saw people calculating stream flow by going on field. They measured width of river, a length, velocity etc and averaged them and used them to calculate stream flow in cfs. Is that method (float method etc) used to get a value for the flow rate input also ? Or that experiment is different?
There are different ways to calculate. The method you have shared is one of them. In order to get the accurate result make sure the measurement is carried out with seriousness and precision. As many locations in world (especially in the developing nations), there are no sufficient hydrological stations. So one has to rely either on empirical formula or manually measure in field.
Your question is very valid. The choice of boundary condition is governed by the data and information available to you. I strongly suggest you (also all the users) to go through the HEC-RAS manuals that is available in the installed folder. It would offer more insights and clarity.
Hello sir. Thanks for this tutorial. But may I ask if this process is applicable in determining the adequacy of an Irrigation System to holds rainfall water? Thanks
@@_SolutionSeek I'm working on a research paper about Agricultural Irrigation System and I want to run a simulation of it to see if its capable to hold the rainfall intensity around the area of my study.
I noticed you gave a value of 0.001 to the upstream for subcritical flow. Could you kindly explain why subcritical flow had a value for upsteam boundary condition ?
These values have been entered just for the learning purpose. For actual and professional analysis, you have to calculate each and every parameters with preciseness. For the detailed information, I suggest you to reach out to the 'Steady Flow Data' section in 'Basic Data Requirements' of the User's Manual.
@@jeromemensah194 It depends upon whether you have discharge data or not. Say if you have discharge data then also it matters for how many years the data is available. The point is the choice of flood frequency is governed by availability of data and their distribution. The most popular are Gumbell's method and log pearson. However conditions are applied for their use. If you do not have data ie ungauged station then you have to resort to empirical formula.
Bro, always provide meaningful profile names. Use different return periods (example:50 year, 100 year, 1000 year) in profile discharge to observe the change. @@Jimbu1777
Go to any folder that has shapefile. You will find many files with the same name but different extensions. Out of them select the one with '.prj' extension. Hope it helps.
Thanks for your reply. Currently we are doing b-tech final year project, FLOOD INUNDATION MAPPING - we are done the HEC HMS model after that the obtained graphs in HEC HMS, We need to input in HEC RAS what is the next process ? Can you please help me. If possible can you share your Gmail id . Thank you sir
@@ysateesh1659 Wow. very cool. If you've accomplished the HEC HMS task, I'm sure you've already selected the dimensional model (1D or 2D) in HECRAS. If you go through HEC RAS tutorials and read the guidelines, hopefully it won't be a big issue. My best wishes for your project.
@@ysateesh1659 helloo broo actually we r also working for this same project for our b tech project, can u plz give me ur contact info for acquiring some doubts
Thank you very much. This is the most short, simple, effective flood mapping video I have seen till now.
Your kind response means a lot. Thank you. Hope the video was useful.
Is there any process so we can automate cross section lines? I wanted cross section data of whole stretch of river.
In that case, you need to use the HECGeoRAS extension in arcgis which automatically generates cross section lines. Afterwards, it has to be imported to HEC-RAS environment.
When specifying the steady flow boundary conditions, you were using arbitrary values. I'm currently learning how to use the HEC-RAS software. If one wanted to practice using real data, how could I find this information?
If you want to use real data, you need to fetch from from authorized sources such as the government agencies related to hydrology and meteorology.
that is the important point
Thank you, when i open geometry data it gives me the following error "error plotting geometric schematic". When i accept it, it saves me just one cross section. How can i solve it?
Thank you for reaching out. I am not aware of this problem. I hope that you have drawn all river center, banks, etc in correct order (ie from upstream to downstream) and the cross section to be created in left to right direction when looking downstream. Please also try saving the geometric file with a different name(no spaces). Share your findings with us afterwards.
Hello, thank you very much. This was helpful but I have a question please. How do we know what value to input as the flow data. I saw you give a couple of values but looks like random values. I will like to know why we need to input a flow data and how to get what values to input. Thank you
Thank you for your kind words of appreciation. The input value depends upon what sort of data is available with you. Usually but not necessarily, flow discharge is used as input. If you have access to other data then you can use them.
Yes, the values I have entered are random; just for tutorial purpose. You can fetch flow hydrograph, if available for your desired study area, from authorized agencies of government related to hydrology or meteorology. Or you can use empirical formula to calculate it.
Thank you very much for your feedback. I watched a video where I saw people calculating stream flow by going on field. They measured width of river, a length, velocity etc and averaged them and used them to calculate stream flow in cfs. Is that method (float method etc) used to get a value for the flow rate input also ? Or that experiment is different?
There are different ways to calculate. The method you have shared is one of them. In order to get the accurate result make sure the measurement is carried out with seriousness and precision. As many locations in world (especially in the developing nations), there are no sufficient hydrological stations. So one has to rely either on empirical formula or manually measure in field.
@@_SolutionSeek okay, thank you very much. Very helpful
And why is one boundary condition for flow hydrograph and the second for stage hydrograph?
Your question is very valid. The choice of boundary condition is governed by the data and information available to you. I strongly suggest you (also all the users) to go through the HEC-RAS manuals that is available in the installed folder. It would offer more insights and clarity.
Hello sir. Thanks for this tutorial. But may I ask if this process is applicable in determining the adequacy of an Irrigation System to holds rainfall water? Thanks
Thank you for the question. I do not have detailed knowledge about the subject matter that you've raised. I will search for it and answer you.
@@_SolutionSeek I'm working on a research paper about Agricultural Irrigation System and I want to run a simulation of it to see if its capable to hold the rainfall intensity around the area of my study.
@@wrcstrshr Wow. That is so cool. My best wishes.
Hello, May I kindly ask another question please.
In unsteady flow data, how do we know what kind of values to input as boundary condition and why
Unsteady implies there is change in the discharge value.
@@_SolutionSeek thanks
@@_SolutionSeek please 1 more question. What do we have to draw cross sections. What role does that play in modeling
That's a very fair question. I guess it has to do with analyzing the change in discharge, slope and elevation at different places.
@@_SolutionSeek Thank you very much
How can we get manning number for a large river channel
I follow the Chow's Manning's 'n'.
I noticed you gave a value of 0.001 to the upstream for subcritical flow. Could you kindly explain why subcritical flow had a value for upsteam boundary condition ?
Second question is how do I get the upstream value for supercritical flow
These values have been entered just for the learning purpose. For actual and professional analysis, you have to calculate each and every parameters with preciseness. For the detailed information, I suggest you to reach out to the 'Steady Flow Data' section in 'Basic Data Requirements' of the User's Manual.
Thank you. May I ask this. What formula would you suggest is the best for calculating return period in hecras steady flow
@@jeromemensah194 It depends upon whether you have discharge data or not. Say if you have discharge data then also it matters for how many years the data is available. The point is the choice of flood frequency is governed by availability of data and their distribution. The most popular are Gumbell's method and log pearson. However conditions are applied for their use. If you do not have data ie ungauged station then you have to resort to empirical formula.
Okay thanks, but do you mean if I have discharge data I wouldn't have to use those formulae @@_SolutionSeek
And also when the profile names are changed to years (eg. 5yrs , 10 yrs etc), what does it mean. And why do we create 3 or 5 profiles.
The profile name means return period years.
Bro can we just put the profile name as yesterday today and tomorrow and provide the flow rate? Is it a right way?
Bro, always provide meaningful profile names. Use different return periods (example:50 year, 100 year, 1000 year) in profile discharge to observe the change. @@Jimbu1777
Can i use 2D model analysis for steady flow ?
@@Rahad557 For steady flow, use 1D model.
how to get projection file
please help me
Go to any folder that has shapefile. You will find many files with the same name but different extensions. Out of them select the one with '.prj' extension. Hope it helps.
Thanks for your reply. Currently we are doing b-tech final year project, FLOOD INUNDATION MAPPING - we are done the HEC HMS model after that the obtained graphs in HEC HMS,
We need to input in HEC RAS what is the next process ? Can you please help me. If possible can you share your Gmail id . Thank you sir
@@ysateesh1659 Wow. very cool. If you've accomplished the HEC HMS task, I'm sure you've already selected the dimensional model (1D or 2D) in HECRAS. If you go through HEC RAS tutorials and read the guidelines, hopefully it won't be a big issue. My best wishes for your project.
@@ysateesh1659 helloo broo actually we r also working for this same project for our b tech project, can u plz give me ur contact info for acquiring some doubts