arch dam
backstop
bamboo curtain
bank
bar
barrage
barricade
barrier
bear-trap dam
beaver dam
blank wall
block
blockade
boom
breakwater
breastwork
brick wall
buffer
bulkhead
bulwark
cofferdam
dam
defense
dike
ditch
earthwork
embankment
fence
gate
gravity dam
groin
hinder
hindrance
hydraulic-fill dam
iron curtain
jam
jetty
leaping weir
levee
logjam
milldam
moat
mole
mound
parapet
portcullis
rampart
rock-fill dam
seawall
shutter dam
roadblocks
checkpoint
foul-up
hurdle
impediment
milestone
setback