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Tc always showing zero

RichardMarr

Civil/Environmental
Aug 26, 2024
2
Hi...
I am modeling 1176 acres of mostly woods in CT as a single subcatchment.
The land use and soil data extracted by HydroCAD from my AutoCAD files appear accurate and produces a CN=64.
Unfortunately, every HydroCAD run produces a Tc=0 with with approx 7,000 cfs 100 yr, more than double my WinTR55 result.
WinTR55 indicates Tc = .626 hour, but no matter what number I plug in the minimum Tc minutes value in the Settings, Advanced screen, the resulting report's Tc is always zero.
Any ideas?
 
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The minimum Tc is applied only if you enter a Tc value for the subcat. You can even enter zero, but there must be at least one Tc segment in order for the minimum Tc to be applied.

The minimum Tc is normally used to avoid very small values (a few minutes). Since you have a significant Tc of 0.626 hours, why not just enter this value directly into the subcatchment?
 
I had missed that entirely, thank you so much!!!!!!
 

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