Command: swim

Usage: swim <dir|here>
    Swim allows you to enter the streams and rivers of Arda, and swim 
from room to room within them. Be aware that just keeping afloat is
a tiring task, and swimming in any direction requires even more energy.
It should be noted that swimming can become exceedingly dangerous if
attempted while encumbered or tired.  Drowning is a real possibility
while swimming, so watch your endurance closely.  To stop swimming
you must move onto dry land.  To start swimming, swim in the direction
of water, or if you are on a bridge or certain riverbanks or beaches, 
simply use 'swim here'.