Pros: First of all, I must point out that you included the nav file, which is a very nice thing of you to do. :). After getting into the map, the very first thing I noticed was the sounds, I was like "Holy shit, I'm at a pool" pretty much. Your use of sound scapes is amazing, they are all in the perfect places, such as the pipe. The tunnel system looks realistic and natural, something I would expect to see in a high quality mod. The broken pipe was a nice little thing to put by the destroyed wall, it added a odd sense of realism to the map. And I also must congratulate you on the lighting. It feels sort of broken down, worn out, grungy. Which is exactly the theme this map needs.
Cons: A main bad thing that I noticed was the bad transition on the walls from tile to plaster. It just looks really strange and unrealistic, it doesn't look like they put tile on the wall, but put a tile prefab over the wall. And while we are on walls, the ones in this map are simply boring, they are bland and unattractive in the destroyed sense of the word, they are too nice for the theme of the map. And when I looked up at the lighting, I saw the ugly florescent lights, they would have been fine, but you doubled them up, killing any realism that it had. Your map also has little to NO cover what so ever. With bots it came down to who could camp base longer. And your door ways were pretty boring, just blocks touching one another, like someone took a chainsaw and cut them out. It doesn't seem like they were meant to be there. And finally, one of the gates by an entrance to the tunnel was smaller than the hole, just looks odd.
Improvements: You should put more cover in the map, a very small bit in the tunnels, but more around the pool and in the side halls. You should also add stuff to the top area so it doesn't feel bland, maybe some sort of platforms (Construction), or impassable debris. The pool should be deeper on one end, and once you do that I would lower the water so that the shallow end of the pool is above the water level. You could also add a diving board, or a broken diving board if you want ;). And where the debris in the pool is, you need to put a broken hole in the roof above that. So that it looks like it came from somewhere, rather than someone hauling it in.
Notes: This is a really good map, with improvements it would be amazing. Good work, I can not wait to see more of your maps. (And I hope you do more stalker themed ones ;)).