A control gate is adapted to be installed across a channel for liquids. The Control gate has a barrier member capable of vertical or tilting movement and it is either slidingly or pivotally mounted to a frame of the control gate. In one instance, the control gate has at least one side member attached to the barrier member. A drive member co-operates with the side member(s) to allow raising and lowering of the barrier member to regulate flow of liquid through the control gate. A flow control member allow the liquid to flow over the gate substantially parallel to the floor of the channel. Also described is a method of measuring flow rate through a control gate.