Warning Message 79 - Submerged Primary Device Outlet

[tpd67]

I'm trying to fully understand the cause of Warning Message 79 (HydroCADD Version 6.10). I received the following message:

"[79] Warning: Pond M020 Submerged Pond M019 Primary device #1 OUTLET by 0.37'"

This is a closed drainage system. Ponds M020 and M019 are manholes connected by a 12" RCP. As I understand the message, conditions in Pond M020 result in the peak elevation being 0.37' (4.44") above the RCP invert at Pond M019. This means the pipe is about 1/3 full at the peak flow.

Am I interpreting this correctly? What's the problem with this situation?

 

[ecwcee]

I'm pretty sure that this means Pond M020 is not discharging fast enough. It's building up water, and as that happens it goes back up the pipe and into Pond M019. When I get a message that an outlet is being submerged, I read it is the system is backing up to that level above the top of the pipe. So from what I understand of your message I would think that given the loading on the system, the water level at peak in Pond M019 is 0.37' above the top of the 12" RCP at the outlet. What's the inflow on M019 and the outflow on M020? I don't think that a 1/3 full pipe would necessitate a warning, but maybe I'm just more conservative when it comes to stormwater management.

 

[dirtRx]

You should post this on the HYDROCAD forum. There are many experienced users as well as the software developer Peter Smart who can respond to you question.