Expanding upon Chris’ discussion of where to place bank stations, what should you do about high terrain somewhere in the middle of your cross section? Here is an example: How should we treat the left overbank? It’s hard to tell if the high area next the left bank is isolated (i.e., it would be an […]
What are the implications of having a cross section that is too short and doesn’t extend all the way out to the highest computed water surface elevation? Does it affect the results? Take this cross section for example. It is missing much of the left overbank (presumably). Image courtesy of Adam Bohnoff First of all, […]
One of the limitations of HEC-RAS is that it is a one-dimensional model. Simply put, RAS assumes all flow moves along a singular dimension. For a given cross section, all of the flow is assumed to move either downstream, or all of it moves upstream, along the singular dimension (which can be defined as a […]
The traditional way of changing non-permanent ineffective flow areas to permanent involves going through each cross section, one at a time, in the cross section editor, selecting Options…Ineffective Flow Areas, and then manually checking which ineffective flow areas to make permanent. This can be long and tedious if you have a lot of cross sections […]