Flood peligrosity analysis over a flat area affected by tides. Case study: General Daniel Cerri town, Buenos Aires, Argentina

Abstract

General Daniel Cerri, on the shores of the Bahía Blanca estuary, suffers from pluvial floods and extraordinary wind tides. Two basins drain a short distance from the town center and in turn the tide drowns the drains. A ring of terraced road and railway works modifies the natural runoff network, generating protection effects, but at the same time delaying evacuation due to tides. Field, satellite and chart data were collected to produce a terrain model. Boundary conditions were adopted and the terrain roughness was evaluated. Floods corresponding to storms of a certain recurrence that flow through the structures were simulated, incorporating the effect of the tide, to define the degree of drowning. Depending on the distances and speeds obtained in the simulation, the affected urban areas are delimited and the danger was defined based on international standards. The results of the simulations made it possible to describe the mechanics of the flood in the area and evaluate the degree of danger in the affected areas based on the values ​​of depth and flood speed simulated in each case. There are non-negligible differences between simulated flooded areas with and without tides. The results were put on maps and reveal the flood zones for the different recurrences, as well as the degree of danger.