Analysis of urban flooding from a meteorological perspective applied to two temperate climate cities in Argentina.

CAMPO A.; ZAPPERI, P.; ALDALUR, B.; RAMOS, MA. B.

Toulouse

Congreso; 9th International Conference on Urban Climate jointly with 12th Symposium on the Urban Environment; 2015

In urban areas, flooding is considered the main environmental impact of heavy rains. Knowing in advance the synoptic conditions that can generate these types of events might contribute to the mitigation of damage. The city of Bahía Blanca and the coastal town of Ingeniero White, in the southwest of Buenos Aires Province-Argentina, are characterized by a template semi-arid climate. In intermediate seasons, heavy rainfall events usually occurs causing floods over different urban areas. The aim of this work is to map and analyze the effects of rainfall in Bahía Blanca city and Ingeniero White town considering the synoptic conditions that generated the precipitation events in May 2008 - September 2014 period. Weather conditions were analyzed through synoptic charts published by the National Weather Service and rainfall amounts were measured by means of a network of eleven rain gauges covering both towns. In addition, meteorological data taken from weather stations in Bahia Blanca downtown area and Ingeniero White coastal area were analyzed. To ascertain the effects caused by rainfall in these cities and having previously selected certain areas, the type of impact was assessed once the precipitation event has finished. Most of the heavy rains events were generated by the convective instability preceding cold fronts that reached the area after warm days. With regard to the effects of such events, the main impact is due to floods not only in flat areas, but also in downtown area when sewer drainage capacity overflows. Besides, these storms affect non-paved streets with steep slope rainfall runoff causing erosive processes which make traffic flow difficult.