Cross Section Analysis

[corvette63]

I need to analyse a channel cross section using the manning equation to determine the 100 year flood elevation. Is there a free program that I can use to input the channel geometry and then apply different Q values to get the water surface elevation. I am only going to be doing one section so did not know if Hec Ras would be appropriate?

 

[francesca]

You won't get an answer worth anything using one x-section. HEC-RAS is the best software for this application, but you need to use it correctly. If you're looking for a quick-and-dirty analysis, calculate the normal depth, but please don't use it to set a 100-year flood elevation for anything meaningful like a plat.

 

[gbam]

For a single XSEC, try dl'ng Quick2. If you are only looking for normal depth in a natural channel, then HY8 will provide a rating curve/table for a single XSEC. HY8 is a culvert analysis program but it does compute tailwater conditions. Those are the only two that copme to mind, rt now.

 

[tsgrue]

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From the thread "Hydrology Software" (thread162-201630)

http://www.eng-tips.com/viewthread.cfm?qid=201630&page=1...

For stand-alone non-eroding channel hydraulic analysis and design, I suggesting use HLW (Dodson & Associates Channel and Culvert Hydraulics) or ECMDS (North American Green's Erosion Control Materials Design Software). Both are available for the MS Windows operating system. HLW is available as freeware/trialware or by purchase (full version). The only difference between the HLW freeware/trialware and HLW full version that I can tell is printing, but you can copy and paste all analysis results so that's not much of a limitation! Still, HLW is very inexpensive (I think) and Dodson seems to be a good company, so you might wanna purchase it. ECMDS is freeware. Even though it is targeted at analysis of North American Green erosion blankets, you can also use it for other channel liner types (soil, riprap, vegetation). SWMM5 can be used for stand-alone channel hydraulic analysis and design as well, but doesn't directly perform depth-variable roughness analysis (though irregular/overbank channel flow analysis can be undertaken).

For stand-alone eroding channel hydraulic analysis and design, I suggesting use GSTARS2.1 (USBR Quasi-2D Channel Hydraulics and Sediment Transport), BriSTARS (FHWA Quasi-2D Channel Hydraulics and Sediment Transport), CCHE2D (NCCHE 2D Channel Hydraulics and Sediment Transport), or MMS (USGS 2D Channel Hydraulics and Sediment Transport). All are available for the MS Windows operating system. Make sure you use the GSTARS2.1 version as it has a pretty good GUI whereas later versions do not. I wouldn't use BriSTARS outside WMS as the interface is not user-friendly. Both CCHE2D and MMS have GUIs, but I think MMS is the much better GUI.

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tsgrue: site engineering, stormwater
management, landscape design, ecosystem
rehabilitation, mathematical simulation

http://hhwq.blogspot.com

 

[RWF7437]

Or......................

For One Cross Section, pencil and paper works well.

good luck

 

[onyeuko]

If you can forecaste the worst condition(ie Qmax may be for the 100year flood), then use any hydraulic equation to solve for the depth in the channel. You can also vary your Q and get the relevant discharge heights(elevations). Test drive stormnet as to be able to forcaste the 100year storm. you can also use same soft ware to do the analysis and design(before your driving time runs over) or pass the information from stormnet to SWMM5(this is free and is almost the same as stormnet but lacked some information like storm forecaste)
Good luck