A Plan for the 3rd world Code PSC019 This work aims to propose a Plan of Steps in order to prevent and decrease the impact of a strong flood in a medium size city, in a poor tropical country, exposed to this catastopher because of its proximity to a river that has overstepped its normal bed many times. Despite all the science advances achieved by our society, we are still watching, several calamities in different cities all over the globe, most of them in poor countries, related to floods in urban areas, always meaning material loss and sometimes, human casualties. This work aims to propose a Plan of Steps in order to prevent and decrease the impact of a strong flood in a medium size city, in a poor tropical country, exposed to this sort of catastopher because of its proximity to a river that has overstepped its normal bed several times on its history, during the rain season. This river crosses all the urban area of the city as its four tributaries and because of the disorganised growing process it has had his slopes occupied for homeless families in poor houses without any planning or security. Nowadays, this city attracts industrial investments and aims to grow following the principles of a Sustainable Development but this community still suffers with the terrible losses after the strong rains and its effects are increased by the social situation of this country. This plan aims to create urban objectives for this city and it is formed by three points: - Objectives for the riverbed and slopes inside and outside the urban area; - Objectives for the consolidated urban areas; - The creation of a Settlement Model for the future growing areas. The first point is about the set of actions aiming decrease the effects of the flood on the riverbed and its slopes both inside and outside the urban area. It includes a campaign with the poor families all over the city limits to create conscience about the environmental problems and to prevent them from throwing domestic garbage on the river; the creation, on the urban area, of a intercept drain channel and drain treatment stations on the both edges of the river; the removal of legal or illegal houses built on the river slopes and that are clearly at the risk of crumble during the floods; the control of erosion both on the urban and rural areas; the substitution of bridges and ramps over the river that during the floods contribute to lower the river section by others designed following the principles of hydrodynamics. The second aspect is about the consolidate and dense central areas of the city. The first goal for this area is the creation of a mapping for the different levels of risk in each part. Based on this mapping, the activities of higher priority, such as hospitals, administrative buildings, schools, elderly rooms, could be removed from risk areas to safe ones. Inside the urban area, the central regions contain the most impermeable soils and so give the biggest contributions for the increase of the water volume on the riverbed. Therefore the plan aims the creation of public squares and parks in order to increase the permeability of the soil on these areas. Finally, this plan creates a Settlement Model for future growing urban areas, for social lower level people in substitution of the traditional models because it was thought for amphibious functioning. The basical principle of this model is the elevation of all the buildings above the maximum level reached for the water during the worst floods. Than, the residential, commercial and institutional buildings would be above pilotis saved from the floods. On the ground level there would be only the public ways, public yards and public squares between the buildings in order to increase the permeability of the soil, and car parking below the buildings. For the public mass transport, it would be create a line, connected to the central area for a monorail or any urban train, but also elevated from the ground level, to prevent this area from isolation and to avoid the crossing with the avenues and streets both the existing and the new ones. The several buildings would be linked by elevated ramps to avoid the isolation of any unity in case of flood. During the normal periods this ramps would let there be a direct connection between the buildings and the monorail stations without the need for walking through the ground level. The buildings would also have a solar system of energy impounding and accumulation to keep working the essential activities during a blackout or any emergency. With this plan, we expect the decrease of the damage caused by the floods that have been meaning large material losses for the communities on the poorest regions of the world.