As per the HydroCAD Owner's Manual, "In order for tailwater effects to be automatically accommodated, two conditions must exist: 1) The upper node must use a routing procedure that is "tailwater aware"." and "2) The lower node must use a routing procedure that defines-(this word is in italics) a...
As per the HydroCAD Owner's Manual, pond routing assumes basically a "zero-velocity level pool" and "If the velocity approaching the outlet device(s) is significant, pond routing may underestimate the discharge and overestimate the peak elevation and storage of the pond.".
Questions:
1. What...
Storage-Indication (SI) v Muskingum-Cunge (MC)
Is there a particular scenario or case where MC would definitely be the better option than SI? Other than a governing body's requirement or request....
Also, is there a major difference between the two other than the celerity aspects?
I have subareas I would like to combine and then compare that "total" to another watershed area that is coming in from further upstream. What is the best way to combine those subareas?
Situation:
Wet pond with a catch basin outlet structure that flows to a swale via a pipe (primary). Pretty standard outfall.
The emergency spillway (ES) is designed such that it would flow directly to the swale if needed for an extreme event of if the catch basin / pipe failed for some reason...
I'm trying to write out a statement for our in-house designers why HEC-RAS should be used for a water surface evaluation difference between a pre and post condition in a streambed. A few years ago, Peter wrote, "a reach is intended only for modeling normal flow with a constant cross section"...
If I extended the box higher, how would I separate out the 2 different void %'s?
If I did the custom storage option with a combined storage number, you would definitely not use a surface area component with void %, correct? Basically, "hand" calculate a volumetric number to put in the custom...
Great suggestion for the box, which would be the easiest solution I believe. And HydroCAD would not "look" at the top of the box as being a solid slab per say or maybe that doesn't matter since the water level would surround that top layer anyway? Or am I just way over-thinking it? :-)
BUT...
What is the best way to model the storage component of an infiltration trench that is on a slope, i.e. running inside a swale? At a particular elevation there would start to be two different void percentages, 40% for the stone and 100% for the open swale. And the higher the elevation, the 100%...
Played around with the outlets and removed the exfiltration limits (between EL 14 and 17) and just left it as exfiltration above EL 14 and it appears to be giving better results.
Also, just routed the exfiltration straight to the primary and the results are holding.
From a very technicality...
My real life setup (as it were) is a catch basin outlet with a pipe outfall (EL 14). Going to that pipe is an underdrain at EL 14, biosoil mix from EL 14 - 17, and the top of the catch basin (overflow) is at EL 18.
I set the model's pipe outlet as the primary and then tried modeling the...
Does HydroCAD tell you what the velocity is in a pipe? As per the resizing tool, I'm guessing it's sizing the pipe to handle the given flow, but what about maintaining a minimum cleanout velocity?
For the pipe resizing "tool" (which is an awesome feature by the way), I was trying to go back to my existing drainage area and run that procedure, but the 'Resizing' tab doesn't show up under the calculation settings.
I do have another diagram with a post-developed drainage area going to a BMP...
Also, under "Modeling Rain-Gardens", "Modeling Under-drains", the following statement is shown:
"B) If the growth media restricts the flow of water from the pond, then it becomes the effective outlet control, and the storage definition should include only the (open water) volume above this...
