Hi everyone, this is the first video for
channel and floodplain 2D modeling with HEC-RAS. The objective of this tutorial is to learn how to create a 2D model with HEC-RAS
of the main channel and floodplain. Through this tutorial, I will provide how to prepare terrain model
based on the TIN and DEM data, and create and edit new 2D flow area for
downstream of the dam, considering the confluence with multiple
river tributaries. And then, I will also give how to connect
flow data with flow boundary conditions using the RAS mapper, geometric editor,
and unsteady flow editor. And lastly, I will give how to develop an
unsteady flow simulation plan using the unsteady flow analysis editor
and run the program to see the simulation results in the RAS
mapper. So, before starting the 2D modeling work
for HEC-RAS, you need to download the data I prepared
for you. So, you need to go to my GitHub website,
and then download the data for this tutorial. So, in this GitHub webpage address, I will
also give the link on this video's descriptions. So, you can use to access this
my GitHub website. So in here, you can find HEC-RAS 2D model,
and then you need to download these three zip file.
This is some specific format with the zip. So, you can download these three data, and
then you need to unzip like this folder. So, after downloading these three data
files, and then you need to unzip, then you can find these three folders for this video's tutorial, okay. So, let's create a project file first. So, you
need to go to file and new project. And then in this case, I will use the same
temp directory from the previous videos, but in this case, I also made
another directory, another folder, working folder for HEC-RAS 2D flow, okay. So, in this folder, I will make new project
file. So in this case, I will use 2D model flow, okay. and then click OK. So... just use US customary units, OK. And then, you need to see the this 2D
model flow project file is created. And then, go to this RAS mapper to import
terrain data, first. So, now we can use this RAS mapper, so go
to set projection for this project, okay. And then, we need to find the project file.
So, in this case, you can see this GIS data folder. And just only one projection file is
included on here the directory. You can see some descriptions for that,
just apply and OK. Now we finished the projection, the
coordinate system for this RAS mapper to import terrain data. So, go to tool and
new terrain. And then, you can bring this new terrain
layer window, and then just click this plus button, and then just go to terrain. And then open this BEC 10 feet .flt file, first. This file contains gridded data at 10 feet
postings for channel created from a TIN, okay. So, open... and then, one more things... this
DEM, okay. So, this DEM file is downloaded from USGS
site for the represent the floodplain. So, it would be more lower resolution, okay.
And then just press this create button. Now you can see the status window to
open this terrain data, these two terrain data, okay. It requires some time to import all the
required terrain data. Almost done... So... After this job, you can see the terrain data
on this RAS mapper, okay. So, now we are completed, so just click
close button. So, if you are available so, let's make big
screen to see more details for this terrain data. And then, right-click to zoom to layer. Yes, we are ready to use this terrain data. And then, just double click this terrain data. And then, you can find this plot hillshade
function is checked, okay. So, this is kind of option to see this terrain
data with hillshade option, okay. So... now we selected this option, okay. In this terrain, you can see the big river on
here, this is upstream and this would be downstream, and then you can find many tributaries,
okay. So actually, in this dataset, we used...
would be... in here, in this point... There is one big dam on here. So, we will consider our simulation with
this dam site, okay. So, now let's make geometry file for this
terrain. So, go to geometry and right-click, and add new geometry. In this box, I will use just name of the initial,
okay. Click OK. And then, you can find this initial geometry
is created, okay. So, now we will make 2D flow area with
perimeter, first. So... just check and on this the perimeter. After that, just right-click to press this edit
geometry button So, now we can create this 2D flow area
with the perimeter, okay. Now I will start to create this perimeter.
Form here, I will roughly make the perimeter to have some simulation, 2D
simulation for this river. Okay, so... just roughly I will develop my 2D flow area
mesh here. so... I should reflect this terrain... So again, your this kind of 2D mesh would
be different from my one. So, you can draw more specifically
develop this kind of the 2D mesh areas, okay. So, this would be one tributary point. Just... go up on here, and then just... right-hand
side for the river. This is one more tributary I'm creating this
point. Again, your 2D area mesh would be
different from my one. But please consider this tributary that I
created on here, okay. So... because we should... make some boundary conditions, flow
boundary condition for this tributary to have some flow simulation for the... this
river system, okay. So, I should stop near on here, okay. I just
make this kind of perimeter, and then I will give
name of 2D area, just click OK. Now on here, you can right-click, and then
find edit 2D area property, okay. After that, we need to change this point
spacing with 500 feet, okay. And then, I also change this Manning's n with 0.04. After that, just click generate computation
point. Now we are succeeded to develop this
2D area points, just close. And then, as usual from previous video, we
should inspect this developed 2D mesh. So... just check this computation point, okay. And then, make zoom... so, let's see
this developed grid have any errors for that. So... You can find some the... all the grid have
just one computation point, okay. So, I think most of the this
kind of developed 2D area is not much caused these kind of errors... but sometimes, with breakline or
refinement regions, you can find some possible errors, okay. So, I think it is okay to use, so just go to
terrain and zoom terrain, okay. So, we are ready to use this the developed
terrain data. So, in that case, just... go to 2D area and stop editing, and just
yes, okay. After that, file and save again. So, this was part 1 video for another
tutorial for HEC-RAS 2D model. So, I will continue channel and floodplain
2D modeling with HEC-RAS for the following video. Thank you for
watching!
