Heh, no, we don't use any package software, just straight up TR-20's.
But from what you're describing, it sounds like you're on the right path. If you're using orifice flow, 0.6 is probably the correct coefficient to use, and 3.1 for the weir computation. The length and elevation would be...
It can generally work either way, but you may not be able to just change the coefficient without changing the modeling method. You can either keep it at the 3.1 coefficient for weir flow, and take that width out of the larger weir, or you can make it an orifice with 0.6 and the weir is the...
We've been discussing this around the office today, and can't really find a reason for 1.5 specifically.
In the jurisdictions that we design for, 1.5 (or 1.2 some places) is not a limit, but a design guideline for selecting the size of the pipe for the application. If you do not have...
I agree with cvg, you need to check your hydrology model, and see if the discharges that are being modeled in your HEC-RAS analysis are realistic for the more frequent storms. I would worry less about having more discharge points along the stream, as long as you're correct with the discharges...
There's no way I'd certify that the 100-year floodplain wouldn't increase in such a situation either without a full study. The only way such a widening wouldn't have an effect was if it was completely masked within the existing blockage of the bridge, and that is unlikely given that a widening...
I'd think the major con to something like an infiltration bed placed in a floodplain, as LCruiser gets at, is that the infiltration of such a facility may be minimal at best, as groundwater in a low area like a floodplain is likely to be very close to the surface, leaving you no depth to...