do sump or steel sump tank buried underground need to be above water table? 1

[delagina]

i have a pre-fabricated sump tank that will be buriend underground and anchored to underground footing.
what happens if this sump tank is above water table?

i know on typical foundation we just consider buoyancy but am not so sure about sumps (concrete or pre-fab)

 

[Ron]

As long as the anchorage system considers hydrostatic uplift, it should not be an issue. I have designed numerous lift stations and partially buried package treatment plants that were installed below the water table.

 

[msquared48]

Agree with Ron here. Only thing is that you will need a pump unless you are draining by gravity to a closed system separate from the water table hydrostatics.

Mike McCann, PE, SE (WA)

 

[racookpe1978]

Sounds like the opposite is occurring this time: You normally bury the tank below the (underground) water level, and so you (normally) include the tank's buoyancy when calculating the anchors. This time, the tank is above the water table, so a new question comes up: "Do I include buoyancy if the tank is above the water table, when I used to include it because the tank was below the water table?"

If my assumptions above are correct, then my answer has to be the "safest" assumption: What happens if you do NOT account for worse-case buoyancy (empty tank with extra-deep water table (as if a flood or nearby water pipe breaking)?