I’m starting a new series called “Exploring HEC-RAS”. Each post will discuss a feature in the menu items, starting with the Tools menu item in the Geometry Schematic. Today’s topic is “XS Interpolation Within a Reach”. There are two options for interpolating cross sections in HEC-RAS: “Within a Reach…”, let’s call this Option A, and […]
Another simple, yet very convenient tool not found discussed in the manuals is the ability to zoom in on one of the axes of a graphical plot. This is especially useful when trying to determine if you’ve captured the true peak discharge in a steeply rising hydrograph. Take the following example: an unsteady flow dam […]
I don’t think you’ll find this anywhere in the manuals, but HEC-RAS has a very convenient tool for measuring lengths and slopes in the Geometry window and just about any graphical plot. It only works in the geometry window if your RAS model is georeferenced, as it measures distances based on coordinates. However, in the […]
So you want to control HEC-RAS from a external program. Perhaps, you have a lot of plans to run and want to run in batch mode. Maybe you wish to run HEC-RAS, evaluate the results, make some changes, and rerun HEC-RAS-all automatically, on its own, while you’re at home with the family. The good news […]
As RAS model development is done more and more through GIS, using the HEC-GeoRAS extension, cross section point filtering is becoming a standard part of the HEC-RAS model development exercise. It’s not too uncommon for a model created in GIS to have multiple hundreds of cross section station elevation points. This is normally not a […]
If you have built enough HEC-RAS models, you’ve probably discovered that having data in different vertical datums is a bit of a pain. RAS lets you adjust the vertical datum of individual cross sections (under “Geometric Data”, “Cross Section”, “Options”, “Adjust Elevations”) or portions of the model (“Geometric Data”, “Tools”, “Datum Adjustment”). However, I have […]
Lateral structures can be used in HEC-RAS to transfer flow from a river/reach to a storage area, or to another river/reach. With the coming release of HEC-RAS with 2D capabilities (estimated beta release January/February 2014), you’ll be able to hook a river/reach to a 2-D area using a lateral structure. Although its primary function in […]
I am working on a dam breach project where I’m trying to simplify a complicated model with dozens of tributaries and storage areas. In the process, I’m converting a few tributaries into storage areas (which are surrounded by other storage areas). For example, I want to convert the reach below (from 5.43 to 0.55) to […]
One of the most frustrating aspects of unsteady HEC-RAS modeling can be the model stabilization process. You know, you’ve gone to great lengths collecting the best survey/topo data and solid hydrology. Then you’ve painstakingly spent hours…possibly days entered all of that data only to find that once you press the “Compute” button, the model crashes. […]
I just received this question about downstream boundaries in HEC-RAS, and thought it would make a nice post here on RASModel.com. “…regarding the boundary condition, if I use critical depth instead of normal depth will it be unacceptable? When choosing the normal depth I need to enter a slope, can i use just one slope […]