Abstract:
Flooding events have been reported since 1920s in the Anhangabaú urban catchment located
in the commercial central area of São Paulo (Brazil). This catchment has approximately 95%
of the area occupied by buildings and roads (one of the roads services more than 200,000
vehicles per day). This paper presents the results of the assessment options for flood
attenuation in Anhangabaú catchment. The objective of this study was fulfilled by (i)
modelling the current urban drainage hydraulic conditions, (ii) analysing the effects of
building underground stormwater reservoirs, and (iii) analysing the consequence of
considering SUDS options to reduce flood extent and magnitude. The modelling was carried
out for all conditions/options using the EPA SWMM software. This study showed that the
existing system's capacity is insufficient to cope even with short return period storms. The
stormwater reservoirs considered in this study as a flood attenuation option have performed
satisfactorily. The options based on implementation of SUDS (e.g. infiltration trenches) can
also reduce the flood peaks for 2 year return period storms; however, they seemed not
adequate to this catchment because the catchment is fully developed and densely populated,
with high percentage of impervious areas, and, consequently, with limited free available areas
to build such structures.
