boundary
building
canal
change
color
dam
day
dyke
edge
energy
falling
feature
flood
flowing
form
front
horizontal
hydroelectric
in
lake
lock
made
motion
nature
non urban
outdoors
park
power
rapid
reservoir
ripple
rippled
river
running
scene
sluice
small
stream
supply
technology
vertical
view
wall
water
waterfall
weir