Flood hazard has been considered for long as a threat to urban development. But stakes in relation to sustainable urban development change the view urban planner have concerning the future of flooding zones. The comparison between French and British situation shows us two different ways to produce and implement flood control legislation. In France, it is considered as a quite up-bottom approach, contrarily to Great Britain were negotiation, assessment and dialogue at a local level are developed. This manner to put into practice flood control strategy encourages a rooted risk culture, a better acceptability and a local management of flood policies. But this ambition is only possible because of the existence of knowledge construction promotion and diffusion tools, at a territorial level.