Im pretty sure the "water tanks" are above ground fuel tanks for an airport. Which would explain the vantage point of the photo (ie. from the air). Although it seems to small a structure the tower in the lower right kind of looks like a control tower. I looked at a few major airports on google maps and they all have tanks like that (different number and configuration of course). I would guess from what I've seen that this pic is from a medium size international airport.