Evaluation of flood exposure in anthropic environments applied to different areas in the region of Bucaramanga, Colombia

Abstract

Floods are natural conditions of the riverbeds, but these manifestations in recent decades have increased their frequency, duration and intensity led to a significant increase in the impacts generated on emerging elements of the social fabric in the regions evaluated for this study (Rio Frio, Rio de Oro, and Manco Rivers). This evaluation is based on the degree of exposure of the infrastructure in different return periods (Tr), where the hazard model created by the design of the flood and speed levels on the flooded areas classified into 5 categories (low, medium, high, very high and extreme) is taken as a basis, and, in turn, will estimate the thresholds and recurrence based on the historical flood record. From this, it is observed that, for the three selected areas there is a high probability of generation of a critical flood with a record of rainfall 24 h in a Tr of 25 years or the accumulation of rainfall of 10 days, with values for the Rio Frio River of 106.6 − 123.8 mm, for the Rio de Oro River of 108.6 − 125.2 mm, and for the Manco River of 116.8 mm, the latter being subjective to the Tr of 25 years or to the follow-up of 5 days and later. As well, it was observed that the three areas present a marked exposure on the Tr of 25 years. This evaluation is a tool of great value within environmental diagnostics, in urban planning, in the development of policies aimed at the insurability and protection of water resources and for the design of emergency plans and early warnings.

Keywords

• Return period
• hydraulic calibration
• basins
• HEC-HMS
• HEC-RAS
• hazard-exposure by flooding