Flood risk in northern basin of Río de las Avenidas in Pachuca's Metropolitan Core using multicriteria decision analysis and GIS

During the last two centuries, the municipalities of Pachuca and Mineral de la Reforma, Mexico, have been affected by several flood events, causing affectations in infrastructure, local economy, and fringe settlements. Heavy intensity of rainfall, new housing developments covering previously permeable grounds, probably old or bad design drainage systems are the main causes for this situation. This paper presents a simple approach of urban flood hazard assessment in a region where primary data are scarce. The objectives of this study are to develop a GIS aided urban flood hazard zoning of the two municipalities applying multicriteria decision analysis and to evaluate it by means of uncertainty and sensitivity analysis. The research methodology focused on the analysis of those variables that control the water routing when high peak flows exceed the drainage system capacity. The model incorporates four parameters: distance to the drainage channels, a social vulnerability index, slope and land use and vegetation. A final hazard map for each category is obtained using an algorithm that combines factors in weighted linear combinations.