"what are they for?"
The slab you see is actually an 18" thick concrete deck. Underneath is a large concrete tank. The tank receives water from the Microfiltration building that is ahead of it in the system. These pumps pump the water into and 84" pipeline down to the next building in the process, Revers Osmosis.
BTW: You can judge pretty well from the Carpenter in the background but the top of the motors are about ft above the slab. I was told the Millwrights set at least one of the 2250HP motors today. I'll try and get down to that part of the job in the next couple days to get a pic.
It's probably more info than most would want but here is a link to a website about the job. It explains the whole system and has monthly construction updates with pictures.
http://www.gwrsystem.com/
