You can build a flower pond on the concrete floor, yes! But don't water it too much. It's good to have soil. First, make some holes in the concrete floor, then insert the pipe into the hole and pass through the flower bed. You can punch more holes in the pipe and wrap it with gauze.

This method is called perforated pipe drainage method, and the basements of many communities are cement floors. This method is used to drain water when designing green belts, and so is the flower bed.