HEC-RAS allows for four different gate types that will compute the stage-discharge relationship of that gate for you based on the physical size/shape of the gate and a few empirical coefficients: Sluice Gates, Radial Gates, Overflow Gates (closed top) and Overflow Gates (open air). However, sometimes the built-in gate types don’t quite fit the gate […]
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 […]
Question: When running an unsteady flow model with a single inflow hydrograph, why does my discharge decrease in the downstream direction for a given output profile? Answer: This is called flow attenuation. You see this to varying degrees in all unsteady flow models and it is a real phenomenon. The shallower the reach, or the […]