OK, so the day after my last post I tried to remove the plug...no luck. I then started to chip away at the concrete, but didn't get far. Then, the next day my daughter was born and thi sfell of my radar. Now, 10 months later and I'm thinking about it again. In the past ten months I've had no problems with water, but still would like to be prepared for the next "big" rainstorm.
More about the "sealed spot" in the unfinished side of my basement. It's about 2' from the back wall of my house, and about 4' from the end wall, so roughly in the corner. The plug is not centered, but off to the side abit. There is an old unused water hookup in this part of the basement and I believe it used to be where the washer and dryer were. I took a few pics, but it's kind of hard to tell much from them. ANyone got any ideas? I'm still thinking it could be an old sealed sump pit, and if so there may be drain tiles running to it.
I thought of another thing. Bear with me because it's a very half a$$ed idea. Each time the water table rises, I can hear the water in my two radon remediation pipes well in advance of actually being "in danger" of flooding. If the rain continues on hard, eventually the gurgling stops as the radun pits fill to the top, then it's a matter of minutes before the water will start to seep in (again, each of the two times prior I lucked out as the rain subsided right as this happened, and the table lowered.). WHat I was thinking is, in an emergency situation, what if I turned off the radon fan, cut the PVC, and pumped the water out from the radon pits? Very half a$$ed, but in theory, if the ground is porous under my basement floor, which I think it is, that should relieve the water table much in the way having a sump pit/pump would. I would have to use a utility pump and snake the house down the pipe, but I believe the radon remediation pits are generally dug about 12-24" inches deep. It would be easy to repair the PVC pipe afterwards. Hell, I could add a cleanout type plug and use some silicone caulk so if I ever had to do it again I could just break the silicone and unscrew the plug. I know it's not really a solution, but it seems like it could work in a pinch.
My other thought was, each of the two times the water table rose to the level of my basement floor, I saw water start to come through gaps all over the floor. It didn't seem like one area was any more prone than the other, it just flowed up evenly. It makes me think that the ground below the floor is probably porous enough that if I installed a sump pit, even without drain tile, it would probably work because the water would flow through the porous soil to that spot.