The swamp there do not seem man-made, I think they are
natural.
The tower is located near to the maze garden, if you are coming
from NTUC, you have to cross a bridge over a river, after the
bridge, you turn left and continue walking until you see the top of
the tower on the left side, turn into the path which lead to the
tower and you will reach it.
The tower is next to the mangrove swamp and there's no lamp-posts
there. So it's completely dark at night.