Abstract: A flood defense apparatus including a channel 10 having a base 12 and side walls 14, 16 extending downwardly from a surface level opening 36 to the base 12 so as to be adapted to collect and transfer surface liquid, a channel dividing formation 18 extending generally downwardly from the opening of the channel towards but not to the base, so as to divide the channel into a drainage portion 20 open for the access flow of surface liquid and a chamber portion 22 and to define a liquid communicating portion 24 between the drainage portion and the chamber portion below the dividing formation, and at least one buoyant barrier member 26 received in the chamber portion to be selectively moveable between a first position within the channel and a second position where the barrier member at least partially extends from the channel.