How much water is too much?

[jtech1]

My pool is due to get plastered Sunday. It was pumped out and cleaned last week. in advance of the tropical storm moving up the east coast, I opened one of my drain plugs in the deep end... at the time a little water flowed in. I knew the ground water table was 6" or so above the deep end floor. I left the plug open to see how much change I got during the rain. I now have about 2 to 2.5 feet of water in the deep end. The plug is still open, so I am guessing that this reflects the true ground water level. The deep end is about 20 x 16 by 7.5 deep at the deep point. There is another 30 ft to the shallow end wall.

They are still scheduled to plaster tomorrow. I know there are calculations I can do to determine the approximate height of ground water needed to exert greater force than the weight of the deep end and cause a problem... but I am just looking for some general info about whether this is anywhere near enough to cause an issue... and how PBs plaster a new pool where the water table is up a bit... I have 4 drain pots in the deep end... I am guessing they will run a pump or two during the plastering? My concern is if that does not keep up with the inflow, they will just plug it and plaster.

 

[jtech1]

I will answer my own question...

I estimated the water table to be about 2' above inside edge of gunite (deep end only; still well below the gunite all together in the rest of the pool). They installed a direct hose and pump to my drain fitting and have a pump running at low speed continuously to remove water from under the pool and keep the pressure from building up. They will leave that in until it is fill time. I don't think the water table would have been enough to move the pool, but the pump ensures that I don't have to test that theory.

 

[jtech1]

Interestingly enough, when they removed the pump and hose, water did not rush in... but, instead, it slowly, over 10 minutes or so, rose a few inches... I expect that it may have taken an hour or more to get back to the 2' mark if the plus were left open. We closed them and started filling right away. They probably pumped enough out from under the pool in 30 hours to have filled it! Also interesting... the pump would run in spurts. It would pump a solid stream out of 1-1/2 pipe for 30 seconds or so, then slow to a trickle for a minute or more... then solid stream again... I am guessing that the ground water would flow in and fill up to the point the pump got its prime, then pump down like crazy, then lose prime and not get it again until enough water flowed back into the area. Does that sound accurate as far as how the pump would work?