storage-discharge relationship
storage-discharge relationship
(OP)
I am using HEC HMS to do river reach routing. I have an existing bridge and several proposed models as well. I am trying to compare the existing outflow at 100 year storm (and others) to the proposed outflow at the 100 year storm. I am using Modified Puls routing. I am trying to find out if I can use the rating curve points from HEC RAS as my elevation-flow values to use in the HEC HMS model? If so, from which cross section do I use the rating curve? Upstream of the bridge?, just inside the upstream face?, just inside the downstream face?





RE: storage-discharge relationship
Our justification for using Hydraflow's output in preference to HEC-RAS's for culverts with pressure flow was that HEC-RAS's 1-dimensional calculations were not as accurate in this particular instance as the 3-dimensional volume calculation used by Hydraflow.
Essentially, we modeled small culverts under pressure as normal detention basins, while we retained HEC-RAS's output for bridges with large flows. I should point out, however, that we were designing the culverts and did not want to have any weir flow as the culvert was under a road. When we modeled a bridge, however, we stuck with HEC-RAS as the component of pressure flow was minimal compared to the flow overtopping the abuttments. Also, HEC-RAS's input for bridges is more detailed than that for culverts.
RE: storage-discharge relationship
RE: storage-discharge relationship
it would be hard to find another analytical method that can beat HECRAS for bridge hydraulics.
RE: storage-discharge relationship
IMO this is a good approach to use when measured flows are not available to correlate stage to discharge, especially if the HEC-RAS is set up carefully. If measured flows are available, be sure to use them to validate the HEC-RAS or to directly develop the relationship in HEC-HMS.
RE: storage-discharge relationship
No one ever said if it mattered about which station's rating curve I should use. At and around the bridge station, the curve is a little different. Which station would accurately represent the relationship I need for routing in HEC HMS?
RE: storage-discharge relationship