Hint 61 and Error 62 in reach calculations

[jsf442]

Can someone please help me understand what

Hint[61] :
{node} Submerged xx% of Reach x bottom

and

Error [62]
{node} Submerged xx% of Reach x inlet

mean?

I clicked on the error messages in Hydrocad, but I do not understand the explanations. What is the difference between the hint and the error>

 

[psmart]

Please note the exact wording: Reach BOTTOM vs. INLET.

Hint 61 means that the tailwater elevation is covering part, but not all of the reach BOTTOM. In other words, the tailwater is above the outlet invert but below the inlet invert. Although the tailwater may effect the discharge, it isn't high enough to flow backwards and come out the reach "inlet"

Error 72 means that the tailwater is above the INLET invert. (so the bottom is fully submerged) In addition to possible tailwater effects, this level could cause an actual reverse flow (water coming out of the "inlet"), depending on how it compares to the water surface at the inlet.

The messages indicate a progressively more significant tailwater conditon. In either case, you need to verify that the assumption of normal Manning's flow in a reach is being met. For details see

http://www.hydrocad.net/reach.htm

 

[psmart]

Addition/correction to my last post:

HydroCAD also checks for reverse-head conditions at each time step. WARNING 62 (not Error 72) indicates that the tailwater is above the inlet invert, but is still below the upstream water surface elevation at all times during the routing. This indicates a greater likelyhood of reduced discharge due to tailwater, but NOT reverse-flow potential.

These messages correspond to four progressive reach conditions:

1) Tailwater below outlet invert, so no message.
2) Tailwater partially sumberges bottom, so Hint 61.
3) Tailwater above inlet invert, so Warning 62.
4) Tailwater above headwater, so Warning 63 (reverse head)

 

[jsf442]

Thanks for the explanation psmart