Version 9, which I recently upgraded to, includes several CN values for impervious and unconnected impervious. A house out in the woods of a 2 or 5 acre (or however large)parcel that is sloped towards the woods seems a pretty straightforward candidate for using "roofs - unconnected impervious"...
Where I've noticed this can be an issue is when the impervious is NOT spread throughout the drainage catchment. For instance, I was reviewing a set of plans once for a condominium development. The pre-development was all woods, good condition. In one of the post-development subcatchments all...
TexasPE, I understand you are frustrated, but your last sentence is unjustified and just plain mean spirited. This forum is titled "HydroCAD Stormwater Modeling", which is a very specific modeling software, and this forum is listed under the heading of "Engineering Computer Programs". What...
Gotcha. Sorry about my typing. I'm not that intimately familiar with those units. Sounds like the manufacturers data would be the ticket. Good luck with it!
Wouldn't you be modeling it as two ponds? The first would be the manhole with the Vortex and overflow outlets and the second would be the subsurface detention pond?
If HydroCAD support answered FigureOuter's question, then that has certainly helped him out. Posting the same question here has reached everyone using the software who takes the time to read through these. I understand how you think it's redundant, but it's not a waste of time to anyone who...
Sometimes I'll model everything as one large subcatchment with a single outlet point (i.e. pond, stream etc.). Swales, culverts etc. would then just be part of the Tc calculation. Other projects I need to justify sizes of every ditch and cross-drain culvert to some reviewing authority so I...
